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SA.22c Rubidium Oscillator

1. 05 67 1PPS Firmware VISIONS skeie ke ee eR ERR WEE E B s BEN ERE ME 69 Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 11 List of Tables 12 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 How to Use This Guide This section describes the format layout and purpose of this guide In This Preface m Purpose of This Guide a Who Should Read This Guide m Structure of This Guide a Conventions Used in This Guide a Warnings Cautions Recommendations and Notes a Related Documents and Information a Where to Find Answers to Product and Document Questions a What s New In This Guide Part Number TBD Revision A February 2007 SA 22c Rubidium Oscillator User s Guide 13 How to Use This Guide Purpose of This Guide Purpose of This Guide The SA 22c Designer s Reference and User s Guide provides basic recommendations for designing products to use Symmetricom s SA 22c Rubidium Oscillator The guidelines in this user guide are generic because specific product reduirements vary from application to application This material consists of a brief description of SA 22c design supported by block diagrams description of environmental issues installation guidelines reguired mating connectors and unit operation Who Should Read This Guide This document is intended for engineers and telecommunications professionals who are design
2. No Initialization Complete No Yes E 5 Exit SA 22c 1PPS SA220033 Figure C 5 SA 22c 1PPS Algorithm States Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 73 Appendix C One Pulse Per Second Source Connection 1PPS Algorithm Theory of Operation Initialization State Initialize Zero All Variables Is Coef y2 10 or 100 000 Set To Auto Mode No Set Up Time Constant And Damping Factor Set Startup Flag Set State To Holdover SA220034 Figure C 6 SA 22c Initialize State During initialization the algorithm sets up variables based on the time constant TC and damping factor DF The SA 22c checks for 1PPS input once per second and if present it enters the holdover state Automatic mode is used when the time constant is set to O The SA 22c 1PPS is in the initialization state when there is no 1PPS applied The j command shows the 1PPS count 74 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Holdover State Holdover Confirm DDS is set to value from 2 minutes before holdover adjust if not Add IDif to accumulators and increment count of data points Points gt Sample Size Set State to CalcSlope SA220035 Figure C 7 SA 22c Holdover State Appendix C One Pulse Per Second Source Connection 1PPS Algorithm Theory of Operation Durin
3. Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 57 Appendix B Symmetricom Serial Interface Protocol Using the Symmetricom Serial Interface Protocol Table B 1 Run Mode Commands Continued User Output to SA 22c ee fe Command Name and Description p None To be Specified Displays Control Register q Hex data to set or reset bits To be Specified Set Control Register in the Control Register Allows enabling or disabling of outputs immediately follows the command example q3A t SAVE command To be Specified Saves all changes made Example to SAVE changes Note if the t command is not used unit 5987717 cr defaults to factory settings at next power up Ww None To be Specified Displays Health Monitor data Table B 2 Factory Mode Commands Command Name and User Output to SA 22c Response to Host Description Command DATA a None a gt Goes to Administration mode None Outputs 7 lines of Banner same Displays Unit Information as power up information r Run Mode Enter RUN mode FC mode is Goes to RUN mode disabled enabled updates or reconfiguring defaults in the field It is not a normal Er Note This mode and ADMIN mode allow the loading of new code or operating mode 58 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Table B 3 SA 22c Administrative Mode Commands Appendix B
4. Symmetricom does not A word or term given special emphasis recommend Part Number TBD Revision A February 2007 SA 22c Rubidium Oscillator User s Guide 15 How to Use This Guide Warnings Cautions Recommendations and Notes Warnings Cautions Recommendations and Notes Warnings Cautions Recommendations and Notes attract attention to essential or critical information in this guide The types of information included in each are explained in the following examples Warning To avoid serious personal injury or death do not disregard N warnings All warnings use this symbol Warnings are installation operation or maintenance procedures practices or statements that if not strictly observed may result in serious personal injury or even death Caution To avoid personal injury do not disregard cautions All A cautions use this symbol Cautions are installation operation or maintenance procedures practices conditions or statements that if not strictly observed may result in damage to or destruction of the equipment Cautions are also used to indicate a long term health hazard ESD damage to equipment do not disregard ESD cautions All ESD cautions use this symbol ESD cautions are installation operation or maintenance procedures practices conditions or statements that if not strictly observed may result in possible personal injury electrostatic discharge damage to or destruction of sta
5. operating temperature 20 output frequency 33 ACMOS 31 output signals 37 P p command 56 PCS 20 phase noise 32 power requirement 20 power source and current pulses 36 power up 36 purpose of this guide 14 R recommendations defined 16 related documentation 17 Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 79 Index S Z RMA number 40 run mode commands 54 57 S SDH 20 serial port 21 service information 33 service signal 30 signal LOCK 30 37 lock alarm 21 signal accuracy 37 SONET 20 spur integrity 32 SSIP 21 37 frequency control 31 modifying operation 32 structure of this guide 14 Symmetricom Serial Interface Protocol see SSIP T temperature limits 36 range 20 thermal tape 29 troubleshooting 40 typical applications 20 U upgrades firmware 40 V voltage controlled crystal oscillator VCXO 30 39 W w command 55 warm up cycle 37 warnings defined 16 warranty 40 web address 17 wireless 20 Y y command 66 Z z command 66 80 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007
6. PEN Symmetricom SA 22c Rubidium Oscillator Designer s Reference and User s Guide Revision A May 2007 Part Number 097 16313 201 Symmetricom Inc 2300 Orchard Parkway San Jose CA 95131 1017 U S A http www symmetricom com Copyright 1999 2007 Symmetricom Inc All rights reserved Printed in U S A All product names service marks trademarks and registered trademarks used in this document are the property of their respective owners Warranty Symmetricom warrants the SA 22 Rubidium oscillator will perform in accordance with Symmetricom published specifications and will be free from defects in materials and workmanship under normal use in accordance with Symmetricom published specifications for a period of i one 1 year for the SA 22 electronics and ii twenty 20 years for the Rb lamp bulb and resonator cell The warranty period begins on date of shipment by Symmetricom The foregoing warranty does not cover failures or damages to the unit caused by i loss or damage in transit improper site preparation or acts of God including electrical or environmental conditions ii repairs or attempted repairs by customer iii improper use or misuse by customer iv modification or alteration by customer v customer or third party supplied software interfacing or parts or vi operations outside of Symmetricom published specifications Symmetricom at its own expense and as its sole obligation and custom
7. je LE RARR RR RR N RR AR ER RE Rg ERROR EE OE EGG Rg AR RR RE ER RR RR N RR RR RR RR RR N EGER OCHO Re RR BO Y ER RR RR ER Re qn rr rrr rrr 0 2 0 3 0 4 0 5 HOURS PPS seconds sample ns 4 3 CONSTANT TE REMOVE CONSTANT RMS WINDOW SIZE apoo 0 Processing sg ss Ia MIESE E 3 MINUTES E 0 if both PPS amp diff data FREO OFFSET Plot options FM A xs 999 wl 2 0E 10 1 0E 10 0 0E 0 dit 1 0E 10 2 0E 10 EE KLEE mi nemen nga 0 0 ditt econds t zamole of IPPS Records st of df f Records hes wna HS 10 FNOPPS data USE VINDOWS SHOV YI INFO FOR OPERATING INSTRUCTIONS MT vos el SA220032 Figure C 4 Flywheeling Recover with 1PPS offset gt 1usec In this test the antenna to the GPS receiver is removed The SA 22c is purposely put off frequency long enough to induce a 1PPS error over 1usec When the antenna is reapplied the SA 22c 1PPS recovers by resetting to 1PPS 0 nanoseconds JamSynch This procedure was repeated to cause both a leading and lagging 1PPS Note This test was performed on a unit started cold which is what causes the general curve in the frequency data excluding the intentional offsets Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 71 Appendix C One Pulse Per Second Source Connection 1PPS Algorithm Theory of Operation 1PPS Algorithm Theory of Operation SA 22c qualifies 1 pulse per seco
8. Table 2 1 Hardware and Software Selectable ltems Item Action Hardware 1PPS Output Enable Turn 1PPS output on or off Software Analog Frequency Adjust Enable or disable frequency control function Adjust Frequency Adjust output frequency from the factory preset value HELP Displays the HELP menu View Control Register Displays current settings of the control register Set Control Register Enable or disable outputs View Unit Information Displays SA 22c information stored in firmware View Health Monitor Data Displays history file of error or fault information Note 1 Minimum frequency change is 2E E or f 2 Values less than this are ignored Maximum frequency charge is not constrained Setting the frequency outside of its operating limits may render the unit non functional Susceptibility to Input Noise If you have an application where the output spectrum phase noise and spur integrity is crucial the SA 22c must have a comparatively clean source of dc power free of spurious current or voltage noise Connecting fans heaters and other switching devices to the dc supply powering the SA 22c can result in degraded phase noise and spur performance Best performance is achieved with only one output turned on and the other frequency outputs turned off 32 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Chapter 2 Design Integration Considerations Reliabil
9. a photo detector When the frequency of the applied rf signal corresponds to the frequency of the ground state hyperfine transition of the 87Rb atom an ultra stable high Q rubidium atomic resonance light is absorbed causing a change decrease in photo detector current lpp As the change in current is small modulation techniques are required to be able to extract the desired signal out of the noise background The photo detector current is used to generate a control signal with phase and amplitude information which permits continuous regulation of the VCXO frequency The servo section converts the photo detector current into a voltage then amplifies demodulates and integrates it for high dc servo loop gain RUBIDIUM PHYSICS PACKAGE IE pnt eg Se ER EE ER EE J leu fmon gt SYNTHESIZER Frequency Out fyoo GENERATOR l A fliko MICROWAVE GENERATOR Figure 3 3 Rb Control Loop Block Diagram 5 x 108 f x 10 1nA TYP 4 x 499 SA220017 Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 39 Chapter 3 Installation and Operation Troubleshooting Troubleshooting After installation if the SA 22c unit fails to provide outputs or the rubidium oscillator fails to achieve lock check the following a The external power supply is providing power m The external power supply is providing the correct power m The VO co
10. 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 49 Appendix A Using the Developer s Kit Options for Supplying Power to the Adapter Test Board Figure A 5 shows the physical power supply wiring and jumper settings needed for each option Warning Users need to use the power settings and connectors that are appropriate for one particular option at a time Mixing any combination of these options may result in a system failure and possibly cause damage to the existing circuitry OPTION 1 1 VDC 32VDC SUPPLIED TO E1 GND SUPPLIED TO E2 TB1 IS INSTALLED TB2 AND TB3 ARE OPENED THIS CONFIGURATION GOES THROUGH DC TO DC CONVERTER AND VOLTAGE REGULATOR WHICH SUPPLIES 15V AND 5V TO SA 22c J7 IS CONNECTED TO SERIAL INTERFACE J3 J5 J6 ARE USED FOR SIGNAL OUTPUTS J4 IS USED FOR 1PPS INPUT J2 MUST NOT BE CONNECTED TB1 TB2 TB3 ARE USED FOR MONITORS AND FREQUENCY CONTROL OPTION 2 5V SUPPLIED TO E3 GND SUPPLIED TO E4 15V SUPPLIED TO ES TB2 AND TB3 ARE INSTALLED TB1 IS OPENED THIS CONFIGURATION DIRECTLY SUPPLIES SA 22C WITH 5V AND 15V J7 IS CONNECTED TO SERIAL INTERFACE J3 J5 J6 ARE USED FOR SIGNAL OUTPUTS J4 IS USED FOR 1PPS INPUT J2 MUST NOT BE CONNECTED TB1 TB2 TB3 ARE USED FOR MONITORS AND FREQUENCY CONTROL OPTION 3 J2 26 PIN MOLEX IS INSTALLED 1 VDC TO 32VDC ARE SUPPLIED THROUGH PINS 1 THROUGH 7 TB1 IS INSTALLED TB2 AND TB3 ARE OPENED THIS CONFIGUR
11. Input 1PPS input positive edge triggered 16 DOUT Output UART data out at ACMOS logic levels 17 N A N A N A 18 N A N A N A connector manufacturer s drawings and specifications E Note Refer to Appendix A Using the Developer s Kit for the Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 23 Chapter 1 Description Specifications Table 1 2 SA 22c Design Absolute Maximum Ratings Characteristic 10 Cto 75 C pnl Unit in ambient still air convection Base plate pnis VDD Supply relative to ground 15Vdc Input 5 VCC Supply relative to ground 5Vdc Input 5 VIN Input voltage relative to DIN and 1PPS IN 0 25 to 5 25 V ground regardless of power Supply voltage FREO Analog External Control Freguency control 0 25 to 5 25 V CTRL Pwu Max Warm Up Power 18 5 Watts 10 C base plate 9 3 Watts Po Max quiescent power 25 C base plate 7 2 Watts 75 C base plate 4 6 Watts Twu Maximum warm up time Locktimeto lt 1E 7 5 Mins 25 C TsrG Maximum Storage Temperature 55 to 85 C Vibration operating GR CORE 63 4 4 4 and 5 4 3 up to 1 5g Maximum altitude With respect to sea 30 000 Feet powered unit level Maximum altitude With respect to sea 50 000 Feet unpowered level Table 1 3 SA 22c Design Operating Characteristics E 10 C to 75 C Characteristic Symbol T sn Base plate Units Uni
12. TE 15 i i soo EDD 76 NISI es OR ER Sie ET OE OR EE ET Abe 77 Bls se a EE EE TA OE EE 78 Tn de EE GE AE A hes Un EE eg EE Oe 79 Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 7 Table of Contents 8 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Figures C 1 C 2 C 4 C 5 C 6 C 7 C 8 C 9 C 10 oA 226 Rubidium Oscillator EE et ewe Rer RES EE et 20 SA 22c Rubidium Oscillator Simplified Block Diagram 21 oA dec DIMENSIONS z x ud nbus itt TED be EE orte f Sos tae tss ASE ean 22 Total SA 22c Quiescent Power Dissipation Typical free convection 26 Typical AP1 Level TEMPCO 10 C to 75 C Base Plate Temperature 26 Mounting an SA 22c to a Circuit Board 0 00 eee 28 Suggested Connections for SA 22c Initial Turn on 36 Sequence of Start up Events 38 Rb Control Loop Block Diagram EE EE SE EE Ee de ee 39 SA 22c Developer s Kit Without Heatsink Assembly 43 SA 22c Developer s Kit With Heatsink Assembly iss ss ee 43 Developer s Kit Interconnect Diagram saasaa EE Ee eee eee 44 Block diagram of suggested Test Setup 0000s 49 Power Supply and Output Options iss EE SS es ee se 50 Time and Frequency Control System EE EE EE ss ss ee eens 63 est Benchi io Sue AE OD e Pero bee ee OO EE 64 Flywheeling Recover with 1P
13. cost mass production and can be easily integrated into time frequency and synchronization systems It can be mounted directly onto a circuit board as a component of a module It offers the high reliability and accuracy of a rubidium oscillator in a new design concept benefiting from the many years of experience Symmetricom has gained in fielding tens of thousands of rubidium oscillators Typical Applications The elevated operating temperature range of the SA 22c sets a new high point for this type of atomic reference Compared with traditional quartz oscillators the stability of the SA 22c allows it to maintain excellent frequency control even when the base plate temperature goes above 75 C Even if the host system overheats in fault mode the SA 22c oscillator continues to produce a stable and accurate time or frequency reference The SA 22c is easily integrated into time and frequency systems because of its low profile The unit operates with a low power requirement 15V 45 5V 45 This design is being successfully applied as an OEM component in wireless telecom networks such as digital cellular PCS base stations and SONET SDH digital network timing Linked with a GPS receiver or other external timing reference the SA 22c provides the necessary timing requirements for CDMA cellular and PCS systems The low temperature coefficient and excellent frequency stability extend holdover performance when the GPS signal is not available Tempera
14. order to connect the Adapter Test Board to main power Users must observe proper polarity of the Adapter Test Board in order to avoid potentially damaging the Adapter Test Board as well as the SA 22c Er Note Users must supply a power supply with leads or interface cable Mounting the Unit with the Adapter Test Board The SA 22c along with the adapter test board is designed to mount onto a heat absorbing surface using the six mounting holes During demonstration testing if a heat absorbing surface is not available a suitable heat sink can be ordered as an option are 3 mm in length with a 0 5 mm thread pitch They should penetrate Er Note The mounting screws of the SA 22c are metric not SAE and no more than 3 mm into the SA 22c base plate Figure A 1 shows the mounting of the SA 22c onto the adapter test board Four 5 mm length screws are needed to properly mount the SA 22c onto the adapter test board if the optional heat sink is not used Note To achieve and maintain the highest level of performance for the SA 22c Symmetricom strongly recommends utilizing a suitable means for heat sinking if the user chooses not to purchase the optional heat sink 42 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix A Using the Developer s Kit Mounting the Unit with the Adapter Test Board SA 22C THERMAL TAPE ADAPTER TEST BOARD if A d fi 4 SCREWS 5 MM 5 MM scr
15. the Lock Pin pin 14 see Note 10 on page 69 Note that this 1PPS mode can be changed by the user but cannot be saved If power is cycled to the unit it reverts to the factory default The modes are 0 1PPS Disciplining Disabled Normal Rb Lock Pin functionality Only the Rb loop needs to be locked to indicate a locked condition on pin 14 1 1PPS Disciplining Enabled Normal Lock Pin functionality Only the Rb loop needs to be locked to indicate a locked condition on pin 14 2 1PPS Disciplining Enabled Requires both Rb loop to be locked AND 1PPS synchronization lock to indicate a locked condition on pin 14 Note that there are two types of 1PPS Customer firmware The 1PPS Standard firmware provides an Rb or Rb 1PPS lock indicator at pin 14 and a Service indicator on pin 12 of the SA 22c VO connector The 1PPS LED firmware uses the same functions for pin 14 but pin 12 is reserved for 1PPS lock indication only There is no Service pin on the 7 PPS LED versions The factory default mode set by the g command for each firmware version is a 1PPS Standard Firmware Mode 2 Rb lock and 1PPS lock indicated on pin 14 a 1PPS LED Firmware Mode 1 Rb lock only indicated on pin 14 and 1PPS lock indicated on pin 12 The key sequence to change the output lock indicator mode with the g command is as follows 68 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix C One Pulse Pe
16. 06 SA22 Version 6 01C of 7 2006 Loader Version 3 Mode CNO1 Flag 0004 Unit serial code is 0612SA3763 h current tuning state is 6 Crystal 3938700hz ACMOS 989680 00000000hz Sine 989680 00000000hz Ctl Reg 004C Res temp off BFC53F7D Lamp temp off BFF92B93 FC disabled Srvc high The following is an example of entering the letter h to get the help menu from the SA 22c r h a Set FC Mode f Adjust DDS Frequency delta e 11 i Info show program info j Display lpps Delta Reg k Set lpps TIC 1 Set Service Pin Sense o Set ACMOS Output Frequency N p Display Control Reg q Set Control Reg t Save Tuning Data w Display Health Data x Exit Run Mode H V The following print out shows the response to the command for w for SA 22c Health Data wellness row AData Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 55 Appendix B Symmetricom Serial Interface Protocol Using the Symmetricom Serial Interface Protocol SCont 6012 SerNum 3B8 PwrHrs 8A PwrTicks E291DB HHrs 85 HTicks 16CCE28 HHrs 85 HTicks 165353C P17 4156AE53 P5 3D3C8652 HtrVolt 41852146 Lmp 3F7E1248 Res 3FCS3EEOD LVthermC B8530000 RVthermC B9384000 LVolt 3FAOEAAC VoutC C87BD20F TempLo 412C0000 dTempHi 42B50000 dVoltLo 416156C8 dVoltHi 4185C42A iFpgaCtl 004C dCurTemp 42540000 dLVoutC 3DF9793A dRVoutC 3DE6A30F dMV2de
17. 07 SA 22c Rubidium Oscillator User s Guide 51 Appendix A Using the Developer s Kit Options for Supplying Power to the Adapter Test Board 52 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix B Symmetricom Serial Interface Protocol This appendix provides information on communicating with the SA 22c through the serial interface connector as provided in the Developer s Kit see Appendix A Using the Developer s Kit It includes output examples and a description of commands In This Appendix m Using the Symmetricom Serial Interface Protocol Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 53 Appendix B Symmetricom Serial Interface Protocol Using the Symmetricom Serial Interface Protocol Using the Symmetricom Serial Interface Protocol The Symmetricom Serial Interface protocol SSIP provides communication with the SA 22c through the serial port when connected to a host PC All developer mode commands are a single ASCII letter and require no termination Of the eight RUN MODE commands three require the host to supply data Host Terminal Emulator Setup Set up the comm port of the PC with the following configuration mu Data rate baud or B P S baud rate of the SA 22c is 57 6K No parity a 8 data bits m stop bit a No local echo unit echoes m No hardware or software flow control Note The SA 22c s UART connections
18. ATION GOES THROUGH DC TO DC CONVERTER AND VOLTAGE REGULATOR WHICH SUPPLIES 15V AND 5V TO SA 22c J7 IS CONNECTED TO SERIAL INTERFACE OPTIONAL J3 J4 J5 J6 MUST NOT BE CONNECTED TB1 TB2 TB3 ARE USED FOR MONITORS AND FREQUENCY CONTROL OPTIONAL SA220022 Figure A 5 Power Supply and Output Options 50 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix A Using the Developer s Kit Options for Supplying Power to the Adapter Test Board Option 1 allows the user to directly power the adapter test board with 10Vdc to 432Vdc going to E1 with E2 connected to supply ground Also TB1 needs to be installed while TB2 and TB3 need to be uninstalled In the adapter board this voltage travels through a DC to DC converter and a voltage regulator to supply the SA 22c with the 15Vdc and the 5Vdc it needs to operate For this option J7 is used for serial interface communications J3 J5 and J6 are used for signal outputs while J4 is used for 1PPS input TP1 and TP3 are used for Lock and Service monitor respectively and TP2 is used for providing the analog frequency control if needed In this option J2 must not be connected in order to avoid degraded signal integrity Option 2 allows the user to directly power the adapter test board with separate 15Vdc going to E5 and 5Vdc going to E3 supplies with E4 connected to supply ground Also TB2 and TB3 need to be installed while TB1 needs to be
19. Grounding Figure 1 3 shows the interface circuitry for the 18 pin SAMTEC VO connector and mechanical dimensions All signals including power power return RF output signal chassis ground and monitor lines are routed through this connector All voltage supply and ground lines must be connected at the mating connector for the SA 22c unit to operate properly The SA 22c is constructed with the chassis unit cover and signal grounds tied together at multiple points and with the power supply return isolated from both chassis and signal grounds only by a ferrite bead This robust grounding approach allows for ESD protection and low spurious emissions But it can also lead to ground loop issues for the user Workarounds commonly used to break DC ground loops at a higher level of integration are to use an rf isolation transformer for the sine rf output and or float the transformer secondary winding of the user s power supply Electrical Interface 1PPS Input and Output The 1PPS output signal of the SA 22c unit is positive edge triggered and gated with the rising edge of the clock Its duration for a 10 MHz unit is 400 ns 410 Rise fall time is 4 ns Lock Signal The LOCK signal indicates that the internal Voltage Controlled Crystal Oscillator VCXO is locked to the atomic transition If the Lock signal is LOW once warm up is completed the output frequency is locked to the Rb atomic clock If the LOCK signal is high atomic lock has bee
20. J1 Signal Pin Name Type Signal Function 1 VSS GND Power and signal ground All ground pins must be connected 2 VDD PWR Power Input 15Vdc All power pins must be connected 44 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix A Using the Developer s Kit Interfacing of the Adapter Test Board Table A 1 18 Pin Samtec VO Connector J1 Continued Signal Pin Name Type Signal Function 3 VSS GND Power and signal ground All ground pins must be connected 4 VDD PWR Power Input 15Vdc All power pins must be connected 5 FREQ Analog Frequency control analog voltage 0 to 5Vdc CTRL 6 VCC PWR Power Input 5Vdc 7 1PPS Output 1PPS output may be enabled disabled digitally OUT 8 VSS GND Power and signal ground All ground pins must be connected 9 FACMOS Output Frequency ACMOS signal output 10 VSS GND Power and signal ground All ground pins must be connected 11 VSS GND Power and signal ground All ground pins must be connected 12 SERVICE Output Service required within 30 days based on unit health 13 DIN Input UART data in to SA 22c 14 LOCK Output If low then the SA 22c is locked 15 1PPS IN Input 1PPS input positive edge triggered 16 DOUT Output UART data out at ACMOS logic levels 17 N A N A N A 18 N A N A N A J2 is a 26 pin Molex receptacle connector used for delivering power and transm
21. PS offset lt 1usec EE ss se 70 Flywheeling Recover with 1PPS offset gt 1usec 71 SA 22c 1PPS Algorithm States x 9 a ORE E EDE deae peo D ene 73 SA pet Initialize Stat E ohne E EDE n oed iab eos Es 74 OA 226 HOOVER State L2 x eoe here i Rei OS ra RR C Ese o in Rs 75 BAIE Caleslope SIEL doce ate sg aoe ese dd eR QUEE S 76 SA 226 JamSynch Stale cc ses HEESE Re pee eee dee 77 SA 226 Discipline State svo MERE SARA d Se IR OR ese te RE RR SE 78 Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 9 List of Figures 10 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Tables A 4 B 1 B 2 B 3 C 1 SA 22c Pin Assignment and Function Chart 2000055 23 SA 22c Design Absolute Maximum Ratings llle 24 SA 22c Design Operating Characteristics Es Es se 24 Hardware and Software Selectable Items Es ss se 32 18 Pin Samtec I O Connector J1 EE EE EE es ke ee 44 26 Pin Molex Connector J2 iss 0c eee 45 SMA Connectors Signal Information o oo anaana EE eee eee 47 9 Pin D Sub Connector J7 xd o esq RR RD EE REIR ER E s 47 Run Mode Gormrantds 5 sux tk eee RR A X XR TR RUE ERE be ROS OR 57 Factory Mode Commands EE Od dos Lh rect en lara dec D 58 SA 22c Administrative Mode Commands 0 00000 ee eee 59 1PPS States Returned with the j Command
22. Recovery Normal Flywheeling Recovery Normal FILE NAME selected 1PPS RMS make gx Boer app ists Plet options ite RR e i EE N N N OR N RUSS HEN N OE AU EAE SY EE REST 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 10 0 11 0 120 13 0 14 014 5 PPS seconds sample ns paca EE REMOVE CONSTANT RMS WINDOW SIZE P0 0 Procesin me TE na E BR MINUTES SEO jubemPPssanranta FREQ OFFSET Plot options pe MEE 2 0E 10 GE N N eene pene nen enn pen nenne qn nnn n nnn n pen nnne ng 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 10 0 110 120 130 14 014 5 HOURS dtit seconds i sample ofIPPSRecords ofdufRecords IS fed DS F dio ENOPPS data USE WINDOWS SHOY VI INFO FOR OPERATING INSTRUCTIONS WPS sss qni SA220031 Figure C 3 Flywheeling Recover with 1PPS offset 1usec In this test the SA 22c was synchronized to 1PPS before this data set Antenna is removed at hour 0 and reapplied at approximately hour 12 5 The SA 22c 1PPS output signal had reached an offset of 220 nanoseconds The subsequent frequency change is what returns the 1PPS offset to 0 nanoseconds 70 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix C One Pulse Per Second Source Connection Recovery with JamSynch Recovery with JamSynch 1500 10004 2 Ln en e eo o 500 8 1500 FILE NAME selected 1PPS RMS acing um 1PPS 33 Rs Plot options
23. Symmetricom Serial Interface Protocol Using the Symmetricom Serial Interface Protocol User Output to SA 22c Response to Host Command Name and Description Command DATA a None Outputs 7 lines of Unit Information Same as the i banner same as command in FACTORY mode and power up RUN mode b File from To be Specified Operating this command without valid Symmetricom file will not overwrite the existing self burning data stored in FLASH memory X None X f gt EXIT Administrative mode to FACTORY mode y None Y asks are you sure Soft reset Restarts processor Z None Z asks are you sure Puts unit into a mode where it will wake only when the power is recycled reconfiguring defaults in the field It is not a normal operating mode E Note ADMIN mode allows the loading of new code or updates or Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 59 Appendix B Symmetricom Serial Interface Protocol Using the Symmetricom Serial Interface Protocol 60 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix C One Pulse Per Second Source Connection This appendix describes how to connect a one pulse per second 1PPS source such as a commercial GPS receiver to an SA 22c to achieve long term accuracy and excellent holdover or flywheeling performance In This Appendix Connection Requirements a Backg
24. a low impedance source such as 50 O or any ACMOS gate as long as the input voltage level at the SA 22c pin is met as described above a The SA 22c rubidium oscillator subsystem must be locked to achieve synchronization a The SA 22c must be set up with the proper time constant and damping factor m SA 22c adapter kit is recommended to facilitate setup see Table C 3 for part numbers a PC running Microsoft Windows with terminal emulation program 57600bps 8 bits with no parity IPPS Algorithm Operation There are two parameters that can be modified by the user for 1PPS synchronization using the y command Damping Factor and Tau Damping factor determines the relative response time and ringing in response to each step Values should be between 0 25 and 4 Values less than 0 25 will default to 0 25 while values over 4 will default to 4 Tau or time constant expressed in seconds and determines the time constant of the PLL for following a step in phase for the reference The range of Tau is 5 to 100 000 seconds Values outside this range will cause both the Damping Factor and Tau to change to the factory default settings Factory Default The factory default requires no inputs to the rubidium oscillator from the user The default value for Damping Factor is 1 and the default Tau is 400 These values area good starting point and will work well for most GPS applications Setting the 1PPS Synchronization The followin
25. arding the status of your RMA you may reach our Repair Administration department at 888 367 7966 option 3 You may also e mail your requests or queries to TSDRMA Symmetricom com Our fax number is 559 961 5175 40 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix A Using the Developer s Kit This appendix provides information on using the SA 22c Developer s Kit It includes information on interfacing the Adapter Test Board as well as information on the various options for providing power and viewing signals from the SA 22c through the Adapter Test Board In This Appendix m Introduction a Mounting the Unit with the Adapter Test Board a Interfacing of the Adapter Test Board m Options for Supplying Power to the Adapter Test Board Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 41 Appendix A Introduction Using the Developer s Kit Introduction The SA 22c Developer s Kit is provided by Symmetricom as a design aid and development tool It permits a design engineer to experiment with Symmetricom s SA 22c product in various applications and to determine how to implement it in the most advantageous manner The developer s kit contains a hardcopy of this document the SA 22c unit the adapter test board an optional heat sink application notes and a CD with electronic files documenting the specifications and performance of the unit in
26. are based on 5 Vdc logic E levels However the Developer s Kit contains a TTL to RS232 converter that allows interfacing to a PC Data Format Run Mode Data Format Customer Mode SA 22c outputs are all decimal data as ASCII Coded Hex except for echoed characters Do not convert data to decimal when transmitting to the SA 22c All data are sent to the SA 22c and received back as ASCII Coded Hex The following example shows how data are encoded Er Note Flow control is not permitted in Run Mode Data sent to the SA 22c in run mode should not be encoded The following is an example of output from the SA 22c after power is applied to the unit SA22C by Symmetricom Inc Copyright 2006 SA22 Version 6 01C of 7 2006 Loader Version 3 54 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix B Symmetricom Serial Interface Protocol Using the Symmetricom Serial Interface Protocol Mode CNO1 Flag 0000 DO4D ok Unit serial code is 0612SA3763 h current tuning state is 6 Crystal 60000000hz ACMOS 10000000 0hz Sine 10000000 0hz Ctl Reg 004C Res temp off 1 5410 Lamp temp off 1 9466 FC disabled Srvc high Enter Run Mode FC mode is disabled lpps mode is disabled r The following is an example of the response one gets by entering the letter i to get serial number and other facts of information on the SA 22c rc SA22C by Symmetricom Inc Copyright 20
27. bruary 2007 How to Use This Guide Conventions Used in This Guide Chapter Title Description Appendix C One Pulse Per This appendix describes how to connect a one pulse per Second Source Connection second 1PPS source to an SA 22c Index Provides references to individual topics within this guide Conventions Used in This Guide This guide uses the following conventions a Acronyms and Abbreviations Terms are spelled out the first time they appear in text Thereafter only the acronym or abbreviation is used a Revision Control The title page lists the printing date and versions of the product this guide describes Typographical Conventions This guide uses the typographical conventions described in the table below When text appears this way it means TimeProvider User s Guide The title of a document LOCK An operating mode alarm state status or chassis label Press Enter A named keyboard key The key name is shown as it appears on the keyboard An explanation of the key s acronym or function immediately follows the first reference to the key if required FC mode enabled Text in a source file or a system prompt or other text that appears on a screen r w A command you enter at a system prompt or text you r gt a enter in response to a program prompt You must enter commands for case sensitive operating systems exactly as shown Lock in A word or term being emphasized
28. ce is 2 1 usec the state returns to holdover to collect a second data set When two consecutive slopes are in range the SA 22c s 1PPS output is synchronized to its 1PPS input If the difference is lt 1 usec the algorithm waits 6 more pulses and then advances to the Discipline state Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 77 Appendix C One Pulse Per Second Source Connection 1PPS Algorithm Theory of Operation Discipline State Discipline Move Baseline If Necessary 3E 9 Max Rate Is This 1PPS Inside TIC Window Set State To No Holdover Is IDif Bounce Between O And 1 Initialize Base Line Refine TIC Count Tum Off 1PPS With Estimator Lock Signal Calculate Proportional Integral Derivative Update DDS Save DDS Value Once Per Minute SA220038 Figure C 10 SA 22c Discipline State In the Discipline State the SA 22c uses a PID proportional integral derivative method to steer the 1PPS output of the SA 22c This method means the SA 22c average frequency offset is close to zero You can expect to see some frequency change when recovering from holdover If at any time a 1PPS input signal is more than 330 nanoseconds from its expected value the 1PPS algorithm returns to holdover state If the input source is very stable the SA 22c further refines the input estimate to provide a smoother frequency output Every m
29. d 14 VSS GND Power and signal ground All ground pins must be connected 15 VSS GND Power and signal ground All ground pins must be connected 16 VSS GND Power and signal ground All ground pins must be connected 17 VSS GND Power and signal ground All ground pins must be connected 18 VSS GND Power and signal ground All ground pins must be connected 19 1PPS IN Input 1PPS input positive edge triggered 20 1PPS Output 1PPS output may be enabled disabled digitally OUT 21 LOCK Output If low then the SA 22c is locked 46 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix A Using the Developer s Kit Interfacing of the Adapter Test Board Table A 2 26 Pin Molex Connector J2 Continued Signal Pin Name Type Signal Function 22 N A N A N A 23 VSS GND Power and signal ground All ground pins must be connected 24 FACMOS Output Frequency ACMOS signal output 25 VSS GND Power and signal ground All ground pins must be connected 26 SINE Output SINE signal output 50 ohm J3 J4 J5 and J6 are SMA connectors used for signal outputs J4 is a signal input provided by the SA 22c See Table A 3 for the SMA connectors signal information Table A 3 SMA Connectors Signal Information SMA Tn Type Signal Function J3 1PPS Output 1PPS output may be enabled disabled digitally OUT J4 1PPSIN Input 1PPS input po
30. er s sole remedy for any breach of the foregoing warranty whether express or implied howsoever arising will use commercially reasonable effort to repair or replace the defective unit upon return of such article to Symmetricom s factory Prior to any return customer must contact Symmetricom at www symmetricom com for a return material authorization RMA number authorizing such return Any unit returned to Symmetricom without an RMA number will be returned to customer at its expense Symmetricom reserves the right to disallow a warranty claim following an inspection of the returned unit EXCEPT AS EXPRESSLY SET FORTH ABOVE SYMMETRICOM HEREBY EXPRESSLY DISCLAIMS ANY AND ALL WARRANTIES OF ANY KIND OR NATURE WHETHER EXPRESS IMPLIED OR STATUTORY RELATING TO SYMMETRICOM S PRODUCTS INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTIES OF TITLE MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE OR NON INFRINGEMENT HOWSOEVER ARISING THE RIGHTS AND REMEDIES PROVIDED HEREIN ARE EXCLUSIVE AND IN LIEU OF ANY OTHER RIGHTS OR REMEDIES IN NO EVENT WILL SYMMETRICOM BE LIABLE FOR ANY INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES INCLUDING WITHOUT LIMITATIOM LOS OF REVENUES OR PROFITS BUSINESS INTERRUPTION COSTS LOSS OF DATA WHETHER IN AN ACTION OF CONTRACT TORT INCLUDING STRICT LIABILITY BREACH OF WARRANTY OR OTHERWISE EVEN IF SUCH PARTY HAS BEEN ADVISED OF THE POSSIBLITY OF SUCH DAMAGES Contents Watt MC 3 How to Use This G
31. ews must be used if a heatsink is not installed 5A220018 Figure A 1 SA 22c Developer s Kit Without Heatsink Assembly Figure A 2 shows the mounting of the SA 22c onto the adapter test board and to the optional heat sink Six 10 mm length screws are needed to properly mount the SA 22c with the adapter test board onto the optional heat sink ADAPTER TEST BOARD SA220019 Figure A 2 SA 22c Developer s Kit With Heatsink Assembly Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 43 Appendix A Using the Developer s Kit Interfacing of the Adapter Test Board Interfacing of the Adapter Test Board The adapter test board was designed to allow the user a flexible means of delivering power to and retrieving signals from the SA 22c Additionally the Adapter Test Board also allows the user to electrically integrate the SA 22c into an existing system via J2 Figure A 3 shows the top view layout of the Adapter Test Board with SA 22c attached ALTERNATE 5V AND 15V POWER 4 550 115 570 Figure A 3 DEVELOPER KIT INTERCONNECT DIAGRAM 6 505 165 227 i 3 625 92 075 a 1 950 49 530 n US 62 0 n SA220020 Developer s Kit Interconnect Diagram J1 on the adapter test board is an 18 pin Samtec 2x9 shrouded I O header used for electrically connecting the SA 22c to the Adapter Test Board See Table A 1 for the VO pin configuration Table A 1 18 Pin Samtec VO Connector
32. g assumes the SA 22c has a 1PPS enabled Customer version of firmware at revision 6 05c or higher installed a Connect the SA 22c to the Adaptor Test Board of the Developer s Kit or to a correctly configured equivalent system See Appendix A Using the Developer s Kit a Ensure the terminal emulation program is configured to 57 600 BPS 8 bits no parity no flow control and that the keyboard caps lock is off All input should be lower case Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 65 Appendix C One Pulse Per Second Source Connection Setting the 1PPS Synchronization Apply power to the system You will see header information from the SA 22c displayed similar to the following where you should confirm the firmware version SA22C by Symmetricom Inc Copyright 2006 SA22 Version 6 05C of 7 2006 Loader Version 3 Mode CN03 Flag 0000 C91Flok Unit serial code is 06128A3763 h current tuning state is 6 Crystal 60000000hz ACMOS 10000000 0hz Sine 10000000 0hz Ctl Reg 0044 Res temp off 1 5410 Lamp temp off 1 9466 FC enabled Srvc low Enter Run Mode FC mode is enabled lpps mode is enabled r Note It is not necessary for the SA 22c to be locked to enter the 1PPS configuration commands but it must be locked for actual synchronization to occur Changing the y Coefficients m Atthe r gt prompt type y then 1 then Enter 1 indicates that you wish to ente
33. g holdover 1PPS input statistics are accumulated and periodically the results are calculated CalcSlope State The sample size is set to 120 data points 120 seconds Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 75 Appendix C One Pulse Per Second Source Connection 1PPS Algorithm Theory of Operation Calcslope When the frequency difference between the SA 22c and the 1PPS source is calculated if the difference is lt 3E the state changes from holdover to JamSynch State CalcSlope Calculate Slope This state executes every 120 seconds And Intercept during holdover Set State To Holdover Absolute Slope 3E9 Save Intercept For Possible Use Later Is Startup Flag Set Yes No Set SA 22c Freguency Reset Startup Flag Is 1PPS Intercept gt 1 us Set JamSynch Flag Set State To JamSynch SA220036 Figure C 8 SA 22c Calcslope State 76 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 JamSynch State JamSynch JamSynch Flag Set Is This The Second Pass Set 1PPS Initialized PID Reset JamSynch Flag Turn On 1PPS Lock Signal SA220037 Figure C 9 SA 22c JamSynch State Appendix C One Pulse Per Second Source Connection 1PPS Algorithm Theory of Operation When the SA 22c 1PPS output is compared to the SA 22c 1PPS Input if the differen
34. icom Serial Interface Protocol EE EE se 54 Host Terminal Emulator Setup se SE Ee ee se ee eee 54 Dat Format A d i e ea potat dcc de iss ttr Oa REM s de Red DE walle 54 Factor MOGB Y cau ria edat o casas M acia a exit aas dex od at 56 Serial Interface Initialization llle 57 Appendix C One Pulse Per Second Source Connection Connection Requirements ss iek EE EDE EER EER eae eed DEE DE EG SETA 62 Backgro nd se EER Em 62 IPRS RUNCHONS ospeak eciam wx oos t OS OS te OD EE DER ed 63 System Requirements 000 cece eee eee ee ee ee 64 TIPPS Algatthim Operation EE DAE c e Red DE DER DE ee es 65 Factory Deta lte 25 Stand aaa BEDE ed DE EDE bi ES DR Medos de 65 6 SA22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Table of Contents Setting the 1PPS Synchronization 2 24 35 rupta es EE DE ae BE EER SE 65 Changing the y Coefficients a Dioec eee ee DA BES DEE 66 The y Coefficients Factory Default se EE Es es se 67 THE EO ers EE fore YEN ic d ada t reae Te Yo De GE 67 The SOIT AG EE RET TETTE ERIT QI S t 68 Flywheeling Recovery Normal EE EE EE EE ER ee EE ek ke 70 Recovery with JamSynch ss 2 EER OE PESE Dd eG eise um EE EE EED 71 1PPS Algorithm Theory of Operation cose Gan vehere RE 72 1PPS Algorithm High Level Flow Chart se Es Ee ee ee 73 ipti adi OM SE EE ie DE dece SE EG dk Stace de doses dE es aM ue 74 eso 7 MEC
35. ing installing operating or maintaining time freguency and synchronization systems having a reguirement for a low profile and highly precise frequency generator To use this document effectively you should have a good understanding of digital telecommunications technologies and analog frequency generation and synthesis techniques Structure of This Guide This guide contains the following sections Chapter Title Description Chapter 1 Description This section contains a description of the SA 22c and lists its typical applications It provides information on dimensions performance and connector pinouts Chapter 2 Design Integration Considerations This section contains mechanical issues pertaining to SA 22c mounting and mating recommendations including thermal and EMI considerations external interfaces and grounding frequency control susceptibility to noise and reliability goal Chapter 3 Installation and Operation This section contains the information necessary to properly install and operate the SA 22c unit including a simplified theory of operation and maintenance and warranty Appendix A Using the Developer s Kit This appendix describes the SA 22c developer s kit hardware Appendix B Symmetricom Serial Interface Protocol This appendix describes use of the external communications link software 14 SA 22c Rubidium Oscillator User s Guide Part Number TBD Revision A Fe
36. inute the SA 22c saves the DDS setting in case holdover occurs Since some receivers take a long time to produce 330 nanoseconds of error after signal loss the SA 22c reverts to the DDS value from 2 periods before the 1PPS becomes invalid 78 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Index A a command 56 accuracy of signal 37 ACMOS output freguency 31 administrative mode commands 57 B baud rate 54 Built in Self Test BIST 21 C cautions defined 16 CDMA 20 cellular 20 comm port 54 command control status dialog 21 commands 54 a 56 administrative mode 57 factory mode 57 h 55 help 55 i55 p 56 run mode 54 57 w 55 communication parameters baud rate 54 data rate 54 contamination 29 D data rate 54 digital network timing 20 documentation related 17 E embedded controller 21 ESD 30 external timing reference 20 F factory mode 56 factory mode commands 57 FC mode 56 firmware 21 37 40 firmware upgrades 40 FLL 39 frequency control 31 frequency control signal 31 frequency output 33 frequency locked loop 39 GPS 20 H h command 55 heat sink 29 heater circuits 21 help command 55 i command 55 L LOCK alarm signal 21 LOCK signal 30 37 M magnetic fields 36 mode administrative commands 57 factory commands 57 FC 56 run commands 54 57 modulation spurs 33 mounting recommendations 28 N noise 33 notes defined 16 O
37. itting receiving signals and data to and from the SA 22c all from one connector See Table A 2 for the Molex pin configuration Table A 2 26 Pin Molex Connector J2 Signal Pin Name Type Signal Function 1 VINPUT PWR Power Input 10Vdc to 32Vdc All power pins must be connected 2 VINPUT PWR Power Input 10Vdc to 32Vdc All power pins must be connected Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 45 Appendix A Using the Developer s Kit Interfacing of the Adapter Test Board Table A 2 26 Pin Molex Connector J2 Continued Signal Pin Name Type Signal Function 3 VINPUT PWR Power Input 10Vdc to 32Vdc All power pins must be connected 4 VINPUT PWR Power Input 10Vdc to 32Vdc All power pins must be connected 5 VINPUT PWR Power Input 10Vdc to 32Vdc All power pins must be connected 6 VINPUT PWR Power Input 10Vdc to 32Vdc All power pins must be connected 7 VINPUT PWR Power Input 10Vdc to 32Vdc All power pins must be connected 8 SERVICE Output Service required within 30 days based on unit health 9 DOUT Output UART data out at ACMOS logic levels 10 DIN Input UART data in to SA 22c 11 FREQ Analog Frequency control analog voltage 0 to 5Vdc CTRL 12 VSS GND Power and signal ground All ground pins must be connected 13 VSS GND Power and signal ground All ground pins must be connecte
38. ity and Maintenance The Rb atomic freguency source uses a modulation demodulation scheme with a modulation freguency of approximately 156 Hz Inherent in this approach is sensitivity to noise at multiples of the modulation freguency This noise is coupled through both the heater and electronic power lines to cause modulation spurs on the output freguency Note Avoid the modulation freguency and its lower harmonics EN roughly up to the tenth harmonic Reliability and Maintenance Reliability The SA 22c is designed with a goal of ten years of operation without retuning To accomplish this the major mechanisms impacting the need for maintenance were addressed Thus each SA 22c has been designed to have excess rubidium fill in the lamp to last for the required period sufficient pulling range for the voltage controlled crystal oscillator and sufficient dynamic range of the rubidium control loop Maintenance User Maintenance The SA 22c is considered to be factory serviceable only There is no user service adjustment or maintenance required A monitor signal is provided to allow the user to track indications of pending end of life for the unit with sufficient notice to avoid a total and sudden failure of the unit The key indicator of health is the service indicator that indicates when the Rb physics package or on board quartz oscillator are near their operating or control limits If the Lock signal does not indicate a Rb lock withi
39. ix C One Pulse Per Second Source Connection System Reguirements GPS taks RS 232 PC With Terminal Emulator 1575 MHz ACMOS GPS Receiver 1PPS Signal Time tog Ae ges 1PPS Out 3 3V or 5 0V Power Supply Power Supply HEV 5 5V 45 SA220030 Figure C 2 Test Bench setup System Reguirements The m S following information lists the requirements for 1PPS setup and operation A 22c with 1PPS output enabled m GPS receiver with less than 300 ns noise a One pulse per second input signals must have repeatable rise time with minimal ringing and must conform to the following 1PPS input can be driven by a standard 3 3 volt logic 5 volt CMOS or 5 volt TTL with normal operation at Input voltage logic high 2 00V minimum Input voltage logic high 5 50V maximum Input voltage logic low 0 00V minimum Input voltage logic low 0 80V maximum Maximum DC overshoot must be limited to 5 5V or 10mA whichever is easiest to achieve Maximum DC undershoot must be limited to 0 5V or 10mA whichever is easiest to achieve Minimum pulse width or hold time of 50 ns 64 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix C One Pulse Per Second Source Connection 1PPS Algorithm Operation Input impedance is 100K Q allowing the user to terminate the 1PPS at the input to the SA 22c with 50 Q at the SA 22c input pin or drive the SA 22c high impedance directly with
40. log Frequency Control Mode Example a lt zero or non zero integer gt This command toggles the analog input pin to the unit Freq Cntl between enable and disable In Factory mode the default cr is enabled During factory test the default is set to disable for shipping unless the customer ordered the default to be set enabled f Desired frequency change To be Specified Adjust Frequency from free running center frequency in parts to E 7 Example for a 100E 7 change 100 lt cr gt Example for a 100E 7 change 100 lt cr gt Adjust Unit output frequency Used to discipline the unit The smallest incremental frequency change is 2E e or f 2 Any value less than this will still be used Max value that can be used at one time is 4E 8 For larger frequency changes repeated steps equal to or smaller than 4E should be used Unit always powers up at free running factory set frequency This command is always relative to the free running frequency h None To be Specified HELP command Displays menu i None To be Specified Outputs Unit information While dumping data clock outputs are not guaranteed to meet specifications during the use of this command o N example of command and data to give 10 MHz for a VCXO of 60 MHz is o3 To be Specified The default frequency output is 10 MHz Consult factory for other frequency options
41. mAvg 3F259383 Q Oo OO YYODO TA YHH a The following print out shows how entering the letter a followed by an integer sets the enable disable feature of FC mode Integer zero followed by cr disables FC mode and any nonzero integer followed by cr enables the FC mode r a 5987717 FC mode enabled The following print out shows the control register contents by entering the letter p r gt p Control Reg 204C Factory Mode Data output from the SA 22c in factory mode is not intended for users outside the factory and is not described in this document beyond Table B 1 Caution Using factory mode can result in the erasure of firmware on A the SA 22c rendering it inoperable and making it necessary to return the unit to the factory for re programming 56 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Serial Interface Initialization The serial interface is initialized as follows Appendix B Symmetricom Serial Interface Protocol Using the Symmetricom Serial Interface Protocol Table B 1 defines the SA 22c s Run Mode Commands Table B 2 defines the bit functions of the factory mode commands of the SA 22c Table B 3 defines the administrative mode commands Table B 1 Run Mode Commands User Output to SA 22c bi WA fo Command Name and Description Command DATA a Set FC mode To be Specified Set Ana
42. minutes the unit should be within 1E of center frequency Thirty minutes after applying power to the SA 22c the rf output frequency will be very close to full accuracy refer to SA 22c specifications Note The output frequency of the SA 22c is more accurate than most counters Appropriate measurement equipment can be obtained from Symmetricom Inquire with Symmetricom Marketing or your local sales representative about Symmetricom s line of test and measurement standards Start up Sequence When power is connected the SA 22c begins its warm up cycle After five minutes the rubidium oscillator reaches a locked condition and its output signals will stabilize The accuracy at shipment is lt 5E at 25 C typical applied to the unit but these output signals are not stable until after EP Note Signals appear at the outputs immediately after power is the oscillator has locked After 7 5 minutes the accuracy of the SA 22c oscillator is 1E 9 Performance of the SA 22c unit varies according to the application profile specified by the customer at time of order Refer to the SA 22c product specification for information on application profiles and unit performance To monitor performance and selectively modify it using the SSIP firmware included in the unit connect the unit to the COM port of a PC running Windows Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 37 Chapter 3 I
43. mitations Symmetricom has pioneered the use of rubidium oscillators in telecommunications applications Telecommunications applications often require long term and short term stability beyond the range of free running quartz oscillators For example cellular CDMA systems often require 1PPS signals to be synchronized within 2 us over very long periods of time even when GPS signals are not available To achieve this performance system designers must combine the benefits of short term stability from a rubidium or low noise OCXO with long term stability from GPS Loran C Glonass or Cesium Symmetricom is the leader in system products with microprocessor driven circuitry that uses the GPS 1PPS system to steer various oscillators Cesium Rubidium and Quartz These products make it possible to combine the short term with long term stability Now with SA 22c the solution can be even more cost effective When used with a GPS receiver the SA 22c provides telecommunications system performance levels that rival levels obtained using Cesium oscillators 62 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix C One Pulse Per Second Source Connection 1PPS Functions 1PPS Functions The SA 22c can be configured to a Generate a rubidium controlled 1PPS signal a Measure the difference between an incoming 1PPS signal and the SA 22c 1PPS a Synchronize the SA 22c s frequency and 1PPS output to the i
44. n lost and the SA 22c goes into sweep mode to reacquire lock The sweep ranges from approximately 21 ppm to 21 ppm in approximately a 20 second period During the sweep outputs are maintained but you should not rely on signal accuracy during sweeping If the power source to the SA 22c is OFF the lock output line is low Service Signal The Service Signal is valid when the unit is operating and the rubidium oscillator is locked The Service Signal algorithm monitors the health of the Rb physics package which includes the Rb lamp bulb and resonator cell and the units crystal oscillator that is slaved to the Rb atomic clock 30 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Chapter 2 Design Integration Considerations Freguency Control Analog The Service Signal indicates low when any of the internal operating parameters are near the end of their tuning or adjustment range providing approximately one month s notice of this situation Frequency Control Signal The SA 22c frequency control signal is an analog input between 0 and 5 Vdc that can be enabled or disabled at the factory making it a default setting or by the customer at a later date using the SSIP The Service BIT can be selectable high or low When in use the smallest incremental frequency change is 2E 12 or f 2 The unit always powers up to the preset free running factory set frequency Adjustments to the frequency a
45. n the specified time or the Service signal indicates that the unit has reached the end of its effective life remove the unit and return to Symmetricom for service The Service indicator is valid only when the Lock signal indicates that the unit is locked For information on how to return a unit for service see Repairs on page 40 Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 33 Chapter 2 Design Integration Considerations Reliability and Maintenance 34 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Chapter 3 Installation and Operation This section provides information on details to consider when installing the SA 22c and the procedure to follow when turning on the unit There is an explanation of the start up sequence monitoring performance and theory of operation It also contains a troubleshooting guide customer support information and warranty information In This Chapter m Installation m Start up Sequence m Theory of Operation m Troubleshooting a Repairs Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 35 Chapter 3 Installation and Operation Installation Installation Site Selection The SA 22c can be mounted in any orientation In environments that approach the operating limits of the SA 22c ensure that the temperature limits are not exceeded The SA 22c is sensitive t
46. ncoming 1PPS and provide very long holdover times Figure C 1 shows the SA 22c 1PPS disciplining block diagram When an externally generated 1PPS signal is applied to the 1PPS input pin of a properly configured SA 22c the unit can provide the time interval error difference between the 1PPS input and the 1PPS generated inside the SA 22c see Table C 1 The difference is read using the RS232 communications j command The j command displays the difference between the 1PPS input and the 1PPS generated internally by the SA 22c The j command produces a number representing the number of TICS in a delta register If the SA 22c has a 60 MHz crystal each TIC is 16 7 ns 1 67E 9 Note that this number is in hex format A more convenient configuration is to allow the SA 22c to be disciplined by the incoming 1PPS signal Figure C 2 shows the test bench setup The 1PPS disciplining mode is enabled by default It can be temporarily disabled by issuing the g command followed by a 1 see The g Command on page 68 Typical performance data for this configuration is shown in Figure C 3 and Figure C 4 1PPS JamSynch Quartz Oscillator Rb Physics 1 PPS Divider Time Interval SA22c 1 PPS Counter Algorithm 60 MHz Divider SA220029 Figure C 1 Time and Frequency Control System Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 63 Append
47. nd 1PPS inputs by analyzing the time difference between the SA 22c s 1PPS output and the external 1PPS input This is referred to as the HoldOver state The SA 22c determines whether the 1PPS input is usable by calculating the rate of change in timing measurements that are taken once per second Once a 1PPS input is qualified the SA 22c 1PPS algorithm determines if it is necessary to adjust the counter that produces the 1PPS output JamSynch state The algorithm then begins to adjust the output frequency of the SA 22c to keep the 1PPS output aligned with the 1PPs input This is the disciplining state and the control method is a Proportional Integral Derivatives PID scheme The amount of frequency change and the length of time required to reach 1PPS accuracy can be adjusted by setting y1 damping factor and y2 time constant parameters During this disciplining state the timing of each 1PPS input is compared to the expected value If the offset exceeds 333 nanoseconds the algorithm changes to the HoldOver state and the process begins again Refer to the following figures for additional details 72 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix C One Pulse Per Second Source Connection 1PPS Algorithm Theory of Operation 1PPS Algorithm High Level Flow Chart SA 22c Generated 1PPS Arrives Get TIC Differences 1PPS Between 1PPS Output Yes And 1PPS Input Present Save As IDif
48. nnector may be defective perform a continuity check Note All pins must have a connection in the I O connector This is especially important in the case of the power and ground pins a ls there excess humidity or moisture inside the operating area a Is the ambient temperature below 10 C or above 75 C the unit will not startup properly in excessively cold or hot temperatures Repairs The SA 22c is not field repairable but some firmware upgrades can be done in the field as noted in Start up Sequence on page 37 If the unit fails do not remove the cover of the unit and attempt to make repairs seals covering the two tuning and adjustment holes are torn or EP Note Unit warranty is void if the cover is removed or if the protective removed If the unit no longer operates properly or if it has reached the end of its effective life please visit Symmetricom s web site at www symmetricom com and click the support warranty and repair link You can also use the following link www symmetricom com support warranty and repair repair form aspx prodtype TSD Once you submit your form through the Internet a confirmation will be sent back to you Requests are processed within 24 to 48 hours Once processed you will receive an e mail from the Repair Administration group that provides your RMA number warranty information or repair cost if applicable and the address of where to send the unit for repair If you have questions reg
49. nstallation and Operation Start up Sequence Dialog OK Serial 1 eaeoad Interface Mute maximum 185W Interval varies based on Quiescent Operation temperature of unit at turn on Typically Level varies from 4 6 W to 9 3 W Power 4 5W requires less than a minute depending on temperature of unit off TTL high Osc Lock The lock signal goes low once the unit has completed its warmup cycle 7 5 minutes TTL low active Outputs become present after the RS 232 baud rate is established 2 4 seconds Outputs Present off Service FEE EE i Signal Service signal is valid after oscillator has locked is valid i 2 4seconds 6 secs 7 5 minutes Elapsed Time SA220016 Figure 3 2 Sequence of Start up Events Note The Service signal can be Active High or Active Low depending E on the unit configuration 38 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Chapter 3 Installation and Operation Theory of Operation Theory of Operation The Model SA 22c makes use of the atomic resonance property of rubidium Rb to control the frequency of a quartz crystal oscillator via a frequency locked loop FLL The FLL function block is shown in Figure 3 3 A microwave signal is derived from a voltage controlled crystal oscillator VCXO and applied to the 87Rb vapor within a glass cell The light of a rubidium lamp also passes through this cell and illuminates
50. o external dc and ac magnetic fields refer to specification and should not be installed in locations subjected to strong magnetic fields from transformers or large power supplies A Rb frequency standard is a very precise component and you should employ optimum practices for its use Avoid using a power source that is also providing power to fans or equipment that generates high current pulses Turn on Procedure Use the following steps to power up the SA 22c Caution To avoid damage to the SA 22c do not apply power to the A unit in reversed direction 1 Verify the SA 22c voltage requirement refer to Appendix A Using the Developer s Kit 2 Verify that the power supply is set to the correct voltage and is turned off 3 Connect the power cable to the SA 22c assembly 4 Turn on power Refer to Figure 3 1 for a block diagram of a suggested hook up DC POWER SUPPLY DC POWER SUPPLY SA220015 Figure 3 1 Suggested Connections for SA 22c Initial Turn on 36 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Chapter 3 Installation and Operation Start up Seguence Once the SA 22c is plugged in and is receiving power wait five minutes while the unit achieves atomic lock During this period the monitored LOCK signal should be HIGH Once the unit achieves atomic lock the LOCK signal goes LOW Depending on base plate temperature within five to less than seven
51. ommunicate with the embedded controller through a serial port connection This allows precise frequency control the dynamic frequency selection the ability to enable and disable outputs to query the system s health and acquire information about the unit s serial number operating temperature fault history initiate a self test and other performance indicators The protocol used is Symmetricom s proprietary Symmetricom Serial Interface Protocol or SSIP The simplified block diagram below shows the importance of the digital control in the unit how it controls and monitors all aspects of operation such as the heater circuits of the physics package as well as the selection of outputs 1PPS 1PPS s In Out Discharge Lamp Resonance Cell Filter Amp Y Y Y Y Y Lamp Lamp C Field Cell Microwave Energizer Heater Control Heater Generator An r AT nme AO A i A i A A A A A A A l ACMOS Y Y Y Y Y L Y Proprietary Digital Control Kernel A A Status gt Serial Analog Control pe 15V 25 Power 5V 45 SA220002 Figure 1 2 SA 22c Rubidium Oscillator Simplified Block Diagram Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 21 Chapter 1 Description Specifications Specifications SA 22C UNIT BOTOM VIEW 9 30 Dis 8 25 352 DETAIL A SCALE2 1 A220003 Figure 1 3 SA 22c Dimensions Note The mating connector is a SAMTEC TMMH 109 01 G DV ES A 2 X 9 shrouded heade
52. on A May 2007 SA 22c Rubidium Oscillator User s Guide 25 Chapter 1 Description Specifications 9 3 Watts 10 C 7 2 Watts 25 C 4 6 Watts 75 C Power Dissipation Watts 15 10 5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 Base Plate Temperature C SA220004 Figure 1 4 Total SA 22c Quiescent Power Dissipation Typical free convection 1 00E 10 5 00E 11 Mm EET I N 5 0 00E 00 5 00E 11 1 00E 10 20 10 0 10 20 30 40 50 60 70 80 Ambient Temperature C SA220005 Figure 1 5 Typical AP1 Level TEMPCO 10 C to 75 C Base Plate Temperature Note Refer to the SA 22c Performance Characteristics document for more detailed information 26 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Chapter 2 Design Integration Considerations This section provides information on mounting and mating connectors operating temperature electrical interface and noise susceptibility In This Chapter a Mechanical Considerations m Thermal Considerations m External Interfaces and Grounding m Electrical Interface m Frequency Control Analog a Modifiable Unit Settings m Susceptibility to Input Noise a Reliability and Maintenance Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 27 Chapter 2 Design Integration Considerations Mechanical Considerations Mechanical Considerations Moun
53. r Caution To avoid damage to the SA 22c ensure that power and A ground are properly connected E Note All pins on the VO connector must be connected 22 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Chapter 1 Description Specifications Table 1 1 SA 22c Pin Assignment and Function Chart Pin Signal number TES Type 1 Signal Function 1 VSS GND Power and signal return ground all ground pins must be connected 2 VDD PWR 15Vdc power input all power pins must be connected 3 VSS GND Power and signal return ground all ground pins must be connected 4 VDD PWR 15Vdc power input all power pins must be connected 5 FREQ Analog Frequency control analog input between 0 5Vdc CTRL 6 VCC PWR 5Vdc power input 7 1PPS Output 1PPS output may be enabled disabled digitally OUT 8 VSS GND Power and signal return ground all ground pins must be connected 9 FACMOS Output FACMOS ACMOS output frequency selectable at factory 10 VSS GND Power and signal return ground all ground pins must be connected 11 VSS GND Power and signal return ground all ground pins must be connected 12 SERVICE Output Indicates unit is nearing limits of frequency control and that Service is required within several months 13 DIN Input UART data in at ACMOS logic levels 14 LOCK Output If low indicates Rb oscillator is locked 15 1PPS IN
54. r the Damping Factor a Enter a value between 0 25 and 4 and press Enter see Note 3 on page 69 and 1PPS Algorithm Theory of Operation on page 72 m Atthe r gt prompt type y then 2 then Enter 2 indicates that you wish to enter the Time Constant a Enter a value between 5 and 100000 and press Enter see Note 3 on page 69 and 1PPS Algorithm Theory of Operation on page 72 m Atthe r gt prompt type z This saves the 1PPS configuration data to non volatile memory If the y coefficients are not saved with the z command the SA 22c reverts to the previously saved configuration upon restart The SA 22c responds with the following output see Note 9 on page 69 r z Saving TData 2 serial number 3BE lpps Coefs saved 66 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix C One Pulse Per Second Source Connection Setting the 1PPS Synchronization The y Coefficients Factory Default If the factory default values of Damping Factor 1 and Tau 400 are acceptable for your application no modifications to the y coefficients are required The SA 22c 1PPS disciplining is enabled at the factory allowing the unit to work right out of the box If you wish to return the y coefficients to the factory defaults enter the value 0 for both the Damping Factor and Tau using the process described in Changing the y Coefficients on page 66 This causes the SA 22c to operate at the factor
55. r Second Source Connection Setting the 1PPS Synchronization a At the r gt prompt type g then type either 0 1 or 2 depending on the desired output mode and press Enter E Notes 1 These numbers are in HEX format 2 1ppsStates 0 to 2 Initialize 3 9 Holdover 6 to 8 Disciplining 3 When connecting to a GPS receiver the factory default mode is recommended Start with y1 1 DF and Y2 400 TC in seconds These values work well for most GPS receivers 4 Use z command to save your settings 5 SA 22c Rubidium system locks approx 5 minutes after startup 6 SA 22c initial frequency must be less than 3PPB for 1PPS to lock 7 Initial 1PPS lock occurs between 3 and 5 minutes after both lock and valid 1PPS are present 8 Confirm the firmware version by issuing the i command 9 xxis a value returned which is the hex equivalent of the number of times the table has been written to TData can be either 1 or 2 10 If using the J2 Molex connector on the Adapter Test Board then the Lock pin is 21 and the Service pin is 8 11 If measuring the Lock and Service voltages on the Adapter Test Board then the Lock signal is on TP1 and the Service signal is on TP3 Table C 2 1PPS Firmware Versions Customer Standard Customer LED 6 05c 6 06c Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 69 Appendix C One Pulse Per Second Source Connection Flywheeling
56. rature increases by 1 or 2 C and its power consumption at a given base plate temperature also increases by a few tens of milliwatts As the base plate temperature continues to increase the unit eventually loses lock Above a base plate temperature of 75 C the resonator or lamp heaters shut down as control point temperatures are exceeded and the unit temperature coefficients increase to approximately 6E 19 C Water Condensation and Excessive Humidity Condensation of moisture from the air onto electrical components produces frequency spikes or instability until the heat of the operating unit drives out the water vapor Condensation will not cause a problem for environments meeting the SA 22c specification if the SA 22c base plate thermal ramp rates are controlled so that they rise at less than 2 C minute Excessive Dust Operating the unit in dusty conditions may cause unexpected thermal effects if dust builds up on the top surface Excessive dust will also contribute to contamination in the shell of the mating connector and could cause intermittent loss of signals The SA 22c is shipped in a dust protected ESD resistant bag All connectors on any product must be suitably protected before mating in a dust controlled environment Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 29 Chapter 2 Design Integration Considerations External Interfaces and Grounding External Interfaces and
57. re always relative to the free running frequency of the unit see also Frequency Control Analog on page 31 ACMOS Output Frequency The ACMOS output frequency is equal to the internal crystal frequency divided by 2N N is a number from 1 to 65536 Consult the factory for a list of specific ACMOS output frequencies Frequency Control Analog Greater Than 1E Internal or External Control The external frequency control circuitry is designed so that with no voltage applied at Pin 5 the voltage will self bias to mid range or 2 5V This input can also be turned off via the SSIP to eliminate any source of noise In some versions of the SA 22c this function can be turned off by customer request on power up If it is to be used later it must be enabled through the SSIP refer to Appendix B Symmetricom Serial Interface Protocol Time Response of External Frequency Control The external analog frequency control is a sampled input with a typical response time constant of 154 ms Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 31 Chapter 2 Design Integration Considerations Modifiable Unit Settings Modifiable Unit Settings SA 22c operation is modifiable by the customer Refer to Appendix A Using the Developer s Kit and Appendix B Symmetricom Serial Interface Protocol for information on how to use the SSIP to use these functions Er Note You cannot alter the default power up conditions
58. rious inputs and outputs of the SA 22c depending on which option you use 48 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Appendix A Using the Developer s Kit Options for Supplying Power to the Adapter Test Board Block Diagram of suggested test SA 22C set up Option 1 ADAPTER TEST BOARD Once the SA 22C unit is receiving power wait 3 to 4 minutes while the unit achieves atomic lock During this period the monitored LOCK signal should be HIGH Once the unit achieves atomic lock the LOCK signal goes LOW Block Diagram of suggested test SA 22C set up Option 2 ADAPTER TEST BOARD It is recommended to power up 15V first Once the SA 22C unit is receiving power wait 3 to 4 minutes while the unit achieves atomic lock During this period the monitored LOCK signal should be HIGH Once the unit achieves atomic lock the LOCK signal goes LOW Block Diagram of suggested test SA 22C set up Option 3 or through Molex Connector 1 VDC 32v0C VSS GND e or through Molex Connector 1PPS IN 1PPS OUT ACMOS OUT SINE OUT 50 Ohms ADAPTER TEST BOARD Once the SA 22C unit is receiving power wait 3 to 4 minutes while the unit achieves atomic lock During this period the monitored LOCK signal should be HIGH Once the unit achieves atomic lock the LOCK signal goes LOW siio Figure A 4 Block diagram of suggested Test Setup Part Number 097
59. round m 1PPS Functions m System Requirements m 1PPS Algorithm Operation m Setting the 1PPS Synchronization a 1PPS Firmware Versions a Flywheeling Recovery Normal a Recovery with JamSynch a 1PPS Algorithm Theory of Operation Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 61 Appendix C One Pulse Per Second Source Connection Connection Reguirements Connection Requirements The following connections are required for 1PPS setup Power GPS antenna 1PPS from the source to the SA 22c No serial port communication is required for initial setup unless you want to make changes from the factory default settings Information on setup operation and integration is provided Background GPS technology has made time and frequency synchronization possible available worldwide Connecting the 1PPS output from a commercial civilian GPS receiver to an SA 22c provides a cost effective system that maintains highly accurate time and frequency even when GPS signals become unavailable for example during jamming and antenna maintenance The GPS system provides worldwide 1PPS signals with extremely good long term stability i e lt 1E 71 averaged over 24 hours However the short term stability of this signal is often compromised by various noise sources for example man made atmospheric conditions crosstalk RF multi path or intersymbol interference and GPS receiver oscillator li
60. scillator Contact your local representative or sales office for a complete list of courses and outlines Where to Find Answers to Product and Document Questions For additional information about the products described in this guide please contact your Symmetricom representative or your local sales office You can also contact us on the web at www symmetricom com Whats New In This Guide This is the initial release of this User s Guide Part Number TBD Revision A February 2007 SA 22c Rubidium Oscillator User s Guide 17 How to Use This Guide What s New In This Guide 18 SA 22c Rubidium Oscillator User s Guide Part Number TBD Revision A February 2007 Chapter 1 Description This section contains a description of the SA 22c and lists its typical applications It provides information on dimensions performance and connector pinouts In This Chapter m Overview m Typical Applications m Specifications Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 19 Chapter 1 Description Overview Overview The SA 22c rubidium Rb oscillator is the newest of Symmetricom s family of precision frequency generator components This fifth generation Rb oscillator reflects significant advances in physics miniaturization and integration SA220001 Figure 1 1 SA 22c Rubidium Oscillator Drawing on over 30 years of experience the SA 22c design has been refined for low
61. sitive edge triggered J5 FACMOS Output Frequency ACMOS signal output J6 SINE Output SINE signal output 50 ohm J7 is a 9 pin D Sub connector used for transmitting receiving data to and from the SA 22c via the Symmetricom Serial Interface Protocol SSIP See Table A 4 for the D Sub connector pin configuration AN Warning When using J3 J4 J5 and J6 it is required that J2 not be connected Having J2 connected will cause a loading effect on J3 J4 J5 and J6 which will result in degraded signal integrity Table A 4 9 Pin D Sub Connector J7 Pin rel Type Signal Function Name yp 9 1 N A N A N A 2 DOUT Output UART data out at ACMOS logic levels Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 47 Appendix A Using the Developer s Kit Options for Supplying Power to the Adapter Test Board Table A 4 9 Pin D Sub Connector J7 Continued Pin hate Type Signal Function 3 DIN Input UART data in to SA 22c 4 N A N A N A 5 VSS GND Signal Ground 6 N A N A N A 7 N A N A N A 8 N A N A N A 9 N A N A N A Options for Supplying Power to the Adapter Test Board The SA 22c adapter test board design allows three power supplying options to accommodate the users needs Figure A 4 shows block diagrams of the three options for powering and setting up the SA 22c with the adapter board It also show which connections are used to access the va
62. t in ambient still air convection Min Max Typ Digital Inputs Outputs Vpp Supply relative to 15Vdc input 14 75 15 25 15 V ground Voc Supply relative to 5Vdc input 4 75 5 25 5 V ground 24 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Table 1 3 SA 22c Design Operating Characteristics Continued Chapter 1 Description Specifications Characteristic E DE pymbol Unit in ambient still air convection Dio pnis Min Max Typ Vin High level input DIN 2 5 5 25 5 V voltage 1PPS IN 1 8 5 25 5 V ViL Low level input DIN 0 0 8 V voltage 1PPSIN 0 0 8 V Vou High level output DOUT SERVICE 3 5 5 25 5 voltage LOCK IOH 0 33mA QOH 0mA FACMOS 1PPS 3 5 5 25 5 V OUT IOH 3 5mA VoL Low level output DOUT SERVICE 0 0 4 V voltage LOCK IOL 0 1mA FACMOS 1PPS 0 0 4 V OUT IOL 1 7mA Analog Inputs Outputs VEC Frequency control Range of 1 5E 0 5 2 5 V input voltage with resolution of range 2 OE 12 or 6 5E FACMOS ACMOS 10MHz Consult 5E6711 BE AHz Hz Frequency Output factory for optional ACMOS frequencies Frequency Control AF FR Control Range Analog FREQ CTRL 1 5E 9 4 4 5E 9 AHz Hz pin 6 5E 4 6 5E 9 wide range Digital Interface 1 0E 1 0E 8 AHz Hz AF Fres Frequency Control Resolution 2 04 E 12 AHz Hz Part Number 097 16313 201 Revisi
63. tic sensitive components of the equipment ESD Caution To avoid personal injury and electrostatic discharge Electrical Shock Caution To avoid electrical shock and possible AN personal injury do not disregard electrical shock cautions All electrical shock cautions use this symbol Electrical shock cautions are practices procedures or statements that if not strictly observed may result in possible personal injury electrical shock damage to or destruction of components of the equipment Recommendations indicate manufacturer tested methods or known functionality Recommendations contain installation operation or maintenance procedures practices conditions or statements that provide important information for optimum performance results Recommendation All recommendations use this symbol Note All notes use this symbol Notes contain installation operation or maintenance procedures practices conditions or statements that alert you to important information which may make your task easier or increase your understanding 16 SA 22c Rubidium Oscillator User s Guide Part Number TBD Revision A February 2007 How to Use This Guide Related Documents and Information Related Documents and Information See your Symmetricom representative or sales office for a complete list of available documentation Note Symmetricom offers training courses designed to enhance your knowledge of the SA 22c Rubidium O
64. ting Recommendations To mount the SA 22c to a custom designed circuit card use the SAMTEC mating connector see Figure 1 3 Use the six mounting holes located on the base plate Note Contact Symmetricom for information on an adapter test board P and for information on designing your own interface circuit board Figure 2 1 shows how to mount an SA 22c to a circuit board Use six M3 stainless steel screws with a minimum penetration depth of 2 mm and a maximum of 5 mm SA220006 Figure 2 1 Mounting an SA 22c to a Circuit Board 28 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Chapter 2 Design Integration Considerations Thermal Considerations Thermal Considerations Thermal Tape In order to achieve the highest ambient operating temperature for the SA 22c operating base plate temperature Symmetricom recommends that the bottom base plate of the SA 22c have good thermal contact to the mounting surface It is also very important to maintain a uniform temperature into the base plate of the SA 22c through its mounting points The SA 22c unit operates normally without thermal tape In some field applications the tape may simplify customer system thermal design requirements Warning To avoid personal injury attach the SA 22c to a heat sink to N prevent it from becoming too hot to touch If there is air flow over the unit s top cover the SA 22c s maximum operating base plate tempe
65. trol Signal nannaa ss EE ES cee EE se es ee 31 ACMOS Output Frequency 2 3 225 c5 AE HI EI DRR de Gene C ETRAS 31 Frequency Control Analog is MOER ESE oe p ER EE DROS DR ene RED YE 31 Greater Than 1E 9 Internal or External Control 31 Time Response of External Frequency Control iss Ese 31 Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 5 Table of Contents Modifiable Unit Settings 2 ox x ted ee EE eg DE E DC EE EO 32 Susceptibility to Input Noise llli 32 Reliability and Maintenance is EE eee eee 33 Reliability x p ui aedi tt De ACER ER ls req dee Et SR a 33 MaintenalleB ss wate VER e E EDE E Id d DE ER O E 33 Chapter 3 Installation and Operation liv tea AON POI EE DR RS g a a e a aA Bre 36 Site DC IECHOM is Ss wie DRR ESE DR ig a E EEEE N fee 36 Turn on Procedure RCM 36 Start up Sequence ARE MEES ER ps TP RE eR RD ER RE 37 Theory of Op raioN essi EE KERRIE EDE BOE ER DE RES DE AEE es 39 Troubleshooting tz Cr 40 Repas e EE EO te nade ees iE eee ERA he ETE 40 Appendix A Using the Developer s Kit Gt GCOLIOHOLDE EE DE RS eI ER ae Bol Re eae a Red tee egent 42 Mounting the Unit with the Adapter Test Board EE EE EE Ee 42 Interfacing of the Adapter Test Board EE cece eens 44 Options for Supplying Power to the Adapter Test Board 48 Appendix B Symmetricom Serial Interface Protocol Using the Symmetr
66. ture compensated units are available for those special applications requiring even better temperature performance 20 SA 22c Rubidium Oscillator User s Guide Part Number 097 16313 201 Revision A May 2007 Chapter 1 Description Typical Applications The SA 22c produces a stable frequency with good short and long term stability with excellent spur performance The microprocessor based SA 22c is a more cost effective system design that allows serial command selection and enabling of TTL level digital output frequencies This allows the oscillator output to be divided to a number of different frequencies as opposed to older oscillators with a single fixed output frequency The ACMOS output frequency is selected at the time of order A 1PPS output is an integral part of the design An optional 1PPS input allows the unit to track a GPS or other external reference For more information refer to Appendix C One Pulse Per Second Source Connection For simple applications the SA 22c provides a 5V CMOS compatible Built in Self Test BIST Service and a LOCK alarm signal derived from the basic physics operation This lock signal indicates when the output frequency is locked to the atomic resonance of rubidium When more control over the device is desired an extensive command control status dialog is available In addition to controlling the operation of the oscillator the microprocessor s built in firmware allows an external host computer to c
67. uide Purpose of This GUIDE cp PERE SERE RS EE DR DE be beeen EERS 14 Who Should Read This Guide ow SEE ites wale a EN eot ees 14 Structure of This CUldes creek EE EES SIE EE HE WE BR DR EG 14 Conventions Used in This Guide 2 2522 s ecc Bebe IE Ee Dee KERE SS 15 Warnings Cautions Recommendations and Notes 16 Related Documents and Information 0 0 00 cece eee eee 17 Where to Find Answers to Product and Document Questions 17 Whats New In This Guide 5 ahorra tin qe dos Seed de See CENA eed gee ened 17 Chapter 1 Description OVOIVIGW 1o a san idet uox desti oe Mette ed ede ese E 20 Typical Applications dou eur Pe rto rod P order Hos Skew ane ROS AA DR vd 20 Specifications dence otio tA xau e Ee SE Ea E OU FH S ER 22 Chapter 2 Design Integration Considerations Mechanical Considerations lille 28 Mounting Recommendations cee eee eee eee 28 Thermal Considerations llle 29 Thermal TapB Es RE DE ee Rete S ERE tee Pe EE SS 29 Water Condensation and Excessive Humidity is ss ee ss se 29 Excessive DIO E 5 2 ER E DS ate teg EE EE deleto oe 29 External Interfaces and Grounding anaana ES SS SS SE es eee 30 Electrical Interface SS SS a 30 1PPS Input and Output 2 222 antes WE RE dta tat eed MINAS 30 DOCK SIGN Alas feed aor ue AE iss ete OG c T Luca ee DE he 30 Service Signal rs sere at olive ee fe ee e ee RD Ge un m d 30 Frequency Con
68. uninstalled In the adapter board these voltages travel directly to the SA 22c for operation the 15Vdc should be applied before the 5Vdc For this option J7 is used for serial interface communications J3 J5 and J6 are used for signal outputs while J4 is used for 1PPS input TP1 and TP3 are used for Lock and Service monitor respectively and TP2 is used for providing the analog frequency control if needed In this option J2 must not be connected in order to avoid degraded signal integrity Option 3 allows the user to power the adapter test board with 10Vdc to 32Vdc through the 26 pin Molex connector J2 Also TB1 needs to be installed while TB2 and TB3 need to be uninstalled In the adapter board this voltage travels through a DC to DC converter and a voltage regulator to supply the SA 22c with the 15Vdc and the 5Vdc it needs to operate For this option J7 is used for serial interface communications however J2 also can be used for serial interface communications if the user would rather do so J2 is also used for input and output signals TP1 and TP3 are used for Lock and Service monitor respectively and TP2 is used for providing the analog frequency control if needed however J2 can also provide these monitors and frequency control as well See Table A 2 for Molex pin configuration In this option J3 J4 J5 and J6 must not be connected in order to avoid degraded signal integrity Part Number 097 16313 201 Revision A May 20
69. y default Damping Factor of 1 and Tau of 400 The j Command Press the j key at any time to return the current value in hex format from the Delta Register see Note 1 on page 69 as well as the 1PPS state see Note 2 on page 69 and Table C 1 The output format appears similar to the following r j lpps Delta Reg 0 ppsState 3 r Table C 1 1PPS States Returned with the j Command Description poids Action Being Performed INITIALIZEOSTATE 0 Start up initialization INITIALIZE1STATE 1 Start up initialization INITIALIZE2STATE 2 Start up initialization HOLDOVERSTATE 3 Seeking usable 1PPS JAMSYNCISTATE 4 Synch SA 22c output 1PPS to input JAMSYNC2STATE 5 Synch SA 22c output 1PPS to input DISCIPLINESTATE 6 Keep SA 22c output 1PPS aligned to input by controlling SA 22c frequency PIDCALCSTATE 7 Calculations for disciplining algorithm PDATEDDSSTATE 8 Update SA 22c DDS based on PIDCALCSTATE output ALCSLOPESTATE 9 Calculate slope of incoming 1PPS vs SA 22c 1PPS during holdover See 1PPS Algorithm Theory of Operation on page 72 for additional information on 1PPS states Part Number 097 16313 201 Revision A May 2007 SA 22c Rubidium Oscillator User s Guide 67 Appendix C One Pulse Per Second Source Connection Setting the 1PPS Synchronization The g Command The g command allows you to change the SA 22c to operate in any of three modes which affect the output of

SA.22c Rubidium Oscillator

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