EO Modulator Driver and Source
Contents
1. 1A 24 Customer Service NEW FOCUS Inc Appendix Changing the Frequency of the Model 3363 B The option port on the back of the Model 3363 B is a standard RS 232 serial port The frequency can be changed using a couple of simple commands This appendix will describe how the user can change the frequency if necessary Note that changing the frequency by a drastic amount from the factory setting more than 20 up or down may change the output power range that you see and is not recommended Connect the Option port of the unit to a standard serial port cable plugged into the serial port of your computer The cable is typically a DB 9 male to DB 9 female Note that only GND RX and TX signal lines of the RS 232 cable are used If you are running Windows 2000 launch Hyperterminal on the computer This is a standard program on Windows 2000 and is accessible via Start gt Programs gt Accessories gt Communications gt HyperTerminal You will need to create a new connection with the following settings 19 200 bit s 8 data bits parity none 1 stop bit flow control none If you are running on another operating system any terminal server program that allows you to send and receive characters over the serial port set to the above communications setting will work If you are running another operating system any serial port communications program with its parameters set EO Modulator Driver and Source Append2. All models are meant for indoor use to be operated at altitudes upto 2000 meters and within 0 40 C temperature range Maximum allowed non condensed humidity is 95 with mains supply voltage fluctuation upto 10 of the nominal value Rated degree of pollutions for all models is 2 Ideal for EOM models 4001 4003 4001 4003 4001 4003 4103 44721 4103 4103 44721 4423 4423 Compatible with EOM 4002 4004 4002 4004 4002 4004 models 4104 4104 4104 Frequency range 25 1000 MHz 0 05 40 MHz 45 2000 MHz in 0 001 Hz in 25 100 kHz steps steps Frequency stability Tracks EOM 1 5 ppm 1 ppm resonance when locked Frequency adjust range 5 of center Fixed at fac Fixed at fac aaa tory gt EO Modulator Driver and Source Characteristics 15 Model 3363 A 3363 B 3363 C t RF monitor 16 V V ms 16 Vins 16 Vins aaa ee typical typical Ext osc input x dBm max dBm max a dBm max Extosc input conn OSC Extosc input conn conn Disable input a TTL logic a TTL logic TTL logic high to disable high to disable r to disable Disable RF attenuation RF Disable RF attenuation 45 dBtyp 45 dBtyp 45 45 dBtyp AM modulation input 0 5V 5V pro 0 5V 5V pro 0 5V 5V pro duces max RF duces maxRF duces max RF output output output AM modulation range 0 30 dBm 0 30 dBm 0 30 dBm Option connector buffered VCO RS 232 DB 9 Parallel pot mon SMA fem DB 9 male Power requirement
3. soe j j MHz ree j OO Maaa Awaq mu PATTER PET kid WWW Pld add pad ace La Ld da adil START 151 7500 MHz STOP 152 2500 MHz RBW 3 0 kHz VBW 3 0 kHz SWP 140 ms Figure 9 below shows the resonances of several models of EOM with frequencies ranging from 150 MHz to 1 8 GHz These are typical responses provided here to show the typical range of quality factor Q and return loss you might expect to see results vary with NEW FOCUS Inc modulator model and exact frequency These data were taken under small sienal conditions and at room temperature These plots are intended to help you understand the change in backreflected power and observed modulation depth as you tune either the frequency of the 3363 or the resonant frequency of the modulator itself As you observe the depth of modulation in your system you may observe the modulation depth change over time temperature or drive level Use of the locking function on the 3363 A or use of the tuning slugs in the EOM itself can be used to minimize these variations Practically speaking due to heating of the modulator crystal by the RF power incident upon it you may note that it takes a minute or two for the modulation depth to stabilize as the temperature of the crystal settles at that particular drive level Figure 9 Return loss plots near resonance of several EOM models Return Loss dB Return Loss dB 4001
4. 152 MHz Q 38 4421 450 MHz 0 54 145 150 155 160 440 445 450 455 460 Frequency GHz Frequency GHz 25 35 1 Return Loss dB Return Loss dB 4421 1 2 GHz Q 226 Special 1 8 GHz Q 455 45 i J 7 1 16 1465 117 1475 1 18 1775 177 1779 1781 1 783 Frequency GHz Frequency GHz EO Modulator Driver and Source Characteristics 21 22 Characteristics NEW FOCUS Inc Customer Service Technical Support Service Information and advice about the operation of any New Focus product is available from our technical support engineers Engineers are on duty from 8 00 5 00 PST Monday through Friday excluding holidays For quickest response ask for Technical Support and have the model number option frequency and serial number of your unit which can be found on the back panel of the unit Phone 408 919 1500 Fax 408 980 8883 Support is also available by email techsupport newfocus com We typically respond to email within one business day In the event that your unit malfunctions or becomes damaged please contact New Focus for a return authorization number and instructions on shipping the unit back for evaluation and repair When calling to request an RMA number be sure you have the option letter A B C frequency and serial number handy EO Modulator Driver and Source Customer Service 23 Fuse Replacement Time Lag Fuse Slo Blo Fuse 239P Series 250VAC
5. is a user friendly EO modulator driver which mates a frequency source and a power amplifier with several handy user features in a compact package The unit runs from standard line voltage US or international It is ideal for use with the New Focus line of resonant modulators It can also be used with our broadband EOMs as well with lower resultant modulation depth The Model 3363 A contains a voltage controlled oscillator VCO as the frequency source which is available from 25 to 1000 MHz The VCO source can be tuned over a limited range via a convenient front panel knob In addition the VCO frequency can be set to track the resonance peak of the EOM this locking mode is selectable via a front panel toggle switch The Models 3363 B and 3363 C contain a high stability synthesized frequency source available from 50 kHz to 2 GHz The synthesized source is stabilized to a crystal oscillator for excellent long and short term stability The output frequency is selected to match your EOM at time of shipment however the user may also adjust the frequency over a limited range through the use of an external computer port A front panel toggle switch allows the user to select whether to use the internal frequency source or to use an external source EO Modulator Driver and Source Operation 5 A matched output RF amplifier provides about 30 dBm of power enough to drive any of our resonant EO modulators to provide approximately
6. the switch is expected to be set to Int Source for proper operation The bandwidth of the TTL enable input is in excess of 1 MHz The RF output level and thus modulation depth is provided by a voltage variable attenuator The front panel knob is normally used to adjust this level however an analog voltage from 0 to 5V on the AM modulation input can duplicate this functionality NEW FOCUS Inc When using the external AM modulation the output level knob is expected to be fully counterclockwise minimum output The bandwidth of this input is in excess of 1 MHz A low level preamplifier and an RF power amplifier boost the signal to approximately 30 dB at maximum output The DC power to the RF power amplifier is controlled by the RF out on off switch 3 allowing the RF amplifier to be disabled to change loads EOMs This button effectively attenuates this output by 16 30 dB depending upon the specific RF amplifier model used A directional coupler operated in reverse samples any power reflected back from the EOM The reflected RF signal from the coupler is sent to a power detector which turns this RF into a DC voltage proportional to the reflected RMS signal An amplified version of this signal is provided to the user When the lock free switch is in the lock setting this signal is also used to adjust the VCO voltage to force the frequency to track the resonance of the EOM The locking circuit adds a smal
7. 3 radians of phase modulation The output modulation depth is controlled through a convenient front panel knob providing adjustment from no modulation to full output power A reflected RF power monitor provides a DC signal proportional to the voltage reflected back from the EO modulator For the VCO based option this feature allows you to manually tune the frequency of the drive box to the resonance of the modulator for maximum modulation efficiency or monitor the frequency locking circuit For our fixed frequency synthesizer option it can also be used to fine tune the resonance of our high frequency EO modulators using the integral tuning slug Other usability features include an RF output enable switch to eliminate damage to the amplifier and or EOM while connecting and disconnecting the output an analog AM modulation input and a TTL output disable input Overview of the Unit 6 Operation Shown in Figures 1 and 2 are the front and rear panel of the unit Figure 1 details the layout of A option of the Model 3363 and Figure 2 details the layout of the B and C options 1 Power switch Turns AC power to entire unit on and off 2 AC indicator Lights when unit is powered RF amplifier enable When depressed and LED is lit the RF power amplifier is turned on This switch allows you to disable the RF amplifier when connecting or disconnecting the EO modulator to the RF output 9 without damaging
8. 3363 A configuration and the bottom reflects the Models 3363 B and C configurations EO Modulator Driver and Source Operation 11 Figure 3 Simplified block diagram of Model 3363 12 Operation 90 250 gt Ne Power supply Bea VAC Power Fuse vco Voltage ctrl d be S amp oat DE 1s Directional Q coupler Option Frequency Lock Ext Osc Int TTL AM Output RF Out Reflected VCO aux Free Input Source Enable Modulation Level On Off RF Monitor Ext Osc Internal Source Option A F Synthesi requency Synthesizer RF Voltage ctrl d Fixed I power amp V ae attenuator anes reamp Directional us SN BF out to mod Option Ext Osc Int TTL AM Output RF Out Reflected parallel or serial Input Source Enable Modulation Level On Off RF Monitor Ext Osc Internal Source Options B amp C In the Option A configuration a voltage controlled oscillator VCO provides the sinusoidal frequency source A front panel knob controls the frequency by changing the applied voltage to the VCO The main VCO output is the input to an RF switch and an auxillary output is sent to the option port for monitoring The RF switch provides the ability to use the internal frequency source or an external user provided source If the external oscillator is not connected this switch can be used to provide approximately 45 dB of attenuation The RF switch can also be actuated by an external TTL input When using this external input
9. 63 A model you will likely need to adjust the frequency knob to adjust the output 10 Operation NEW FOCUS Inc frequency to be in resonance with the driver By attaching a common voltmeter to the reflected RF monitor port 10 you can determine if you are at resonance by adjusting the frequency until the signal on the voltmeter is minimized When you are near the minimum you can flip the lock free switch 7 to the lock position to have the VCO frequency track the EOM resonance For the 3363 B and 3363 C models the frequency is fixed at the factory to the frequency specified at time of order By attaching a common voltmeter to the reflected RF monitor port 10 you can monitor the power reflected back by the EOM Some of our high frequency EOM models have a user accessible slug that allows you to tune the resonance of the EOM to match and thus minimize the signal from the monitor port For an FM modulator the easiest way to check for modulation and measure modulation depth is to use an optical spectrum analyzer For an AM modulator one of our detectors is ideal for measuring modulation Using one of our DC coupled receiver models to observe the output signal from the EO modulator is an ideal way to carefully measure modulation depth Operation Details Below in Figure 3 we show a simplified block diagram The top schematic shows the power supply configuration common to all options the middle shows the Model
10. RF voltage reflected back from the modulator When the EOM resonance and the frequency of the driver are equal the signal is a minimum The exact value of the minimum varies depending on drive level and each individual modulator EO Modulator Driver and Source Operation 7 11 TTL Enable Internal Source The allows an external TTL signal to perform the function of the Int Ext Source switch 4 When no external source is connected to 5 a low level nominal 0 V on this input allows the internal generator signal to pass through a high level nominal 5 V disconnects the internal frequency source 12 AM modulation input This allows an external analog voltage 0 to 5 V to modulate the output RF level The output level knob 8 should be fully counterclockwise minimum output when using this input 13 Option port Option A For the option A VCO based models this provides an auxiliary frequency monitor with a fixed output of approximately 10 dBm 14 EAC power input connector AC power to the unit can range from 90 to 250 VAC The door above the power connector contains the fuse The fuse installed in the unit will be appropriate for your location s voltage 15 Frequency Lock indicator Option B or C only This LED should remain lit when the unit is operating properly it indicates that the internal phase locked loop circuit is locked to the internal crystal source 16 Option port Option B or C only For Opti
11. USER S GUIDE EO Modulator Driver and Source Models 3363 A 3363 B and 3363 C V New Focus A Newport Company 3635 Peterson Way Santa Clara CA 95054 USA Phone 408 919 1500 email contact newfocus com www newport com newfocus AX Please read the manual for safety information Warranty New Focus a Newport Company guarantees its products to be free of defects for one year from the date of shipment This warranty is in lieu of all other guarantees expressed or implied and does not cover incidental or consequential loss Refer to Newports Terms and Conditions of Sale for warranty coverage Information in this document is subject to change without notice Copyright 2007 Newport Corporation All rights reserved Document Number 330044 Rev C Contents Operation 5 ISOU DC OB zy t ayka EN dd Joc ATO eco ees 5 Oyerview Ofthe 6 Quick Start We 10 11 Safety NOCE wasn m uuu wp saa usus wau ushussa aha 14 Characteristics 15 SPECINCALONS eisten eeen aR E EN 15 Permormiance Details 44 ti 1 it no atecta EE EEEE A 16 Customer Service 23 Technical SUP POU reces ren Daun guns i qaa 23 T O es accieea enemas ues hata 23 Appendix 25 Changing the Frequency of the Model 3363 B 25 Appendix I 27 Changing the Frequency of the Model 3363 C 27 EO Modulator Driver and Source Contents 3 4 Contents NEW FOCUS Inc Operation Introduction The Model 3363
12. be how the user can change the frequency if necessary Note that changing the frequency by a drastic amount from the factory setting more than 20 up or down may change the output power range that you see and is not recommended Connect the Option port of the unit to your computer using a cable with a DB 9 female connector to DB 25 parallel port connector This cable is available as a separate item from New Focus contact customer service to order this item Launch the control panel software on the computer If the software is not yet installed on the computer you are using please follow the instruction provided with the cable or with the software when you download it as instructed by customer service The display should come up without any error dialogues If there are error dialogues the unit is not connected correctly powered up or you may have to configure your parallel port correctly as per the software installation instructions Type the desired user frequency in MHZ into the Frequency box Click Store Note that making changes to any other configuration parameters may cause unstable or improper operation of the unit EO Modulator Driver and Source Appendix Il 27 Once the computer indicates the new frequency was successfully stored you may disconnect the parallel cable and exit the control panel on the computer 28 Appendix II NEW FOCUS Inc
13. ix l 25 to 19200 bit s 8 data bits no parity 1 stop bit and no flow control will work fine Check that the connection is working and on the status of the synthesizer by typing QUE into the terminal screen The unit should respond with a hexidecimal string of characters for example 0000 12309CE54000 2710 14050060 0A3A 02 20 The actual string will likely differ from this one based on the settings for your unit You can change the frequency by typing FO note the space followed by the frequency in megahertz For example to set the output frequency to 27 34 MHz type FO 27 34 followed by a return the enter key The unit should reply OK on the terminal program Now type S followed by a return into the terminal window This step records the settings into the EEPROM of the synthesizer If you skip this step the frequency adjustment you made will be lost the next time the unit is powered off The unit should again respond OK on the terminal program If desired you may disconnect the serial cable and exit HyperTerminal or whatever terminal program you are running on the computer 26 Appendix NEW FOCUS Inc Appendix ll Changing the Frequency of the Model 3363 C The option port on the back of the Model 3363 C is a standard parallel printer port The frequency can be changed using a small control panel computer program available from New Focus This appendix will descri
14. l dither approximately 40 kHz to the output frequency which is used to track the minimum of the EOM resonance Note that some models frequencies of EOM typically the 4001 4003 series can have spurious resonances that are not at the actual main resonance these can be avoided by first tuning the synthesizer to be very near the main resonance before toggling the switch from free to lock The 3363 B and C models shown at the bottom of Figure 3 replace the VCO based source with a PLL based synthesizer and dispenses with the locking circuit The Option B synthesizer has a RS 232 serial port interface and the Option C synthesizer has a parallel port interface The synthesizer frequency is factory set to the user s desired frequency and use of the computer port is optional only EO Modulator Driver and Source Operation 13 Safety Notice The output RF must be disabled using the RF out on off switch 3 whenever the output 9 is connected or disconnected or damage to the RF amplifier may result There are no user serviceable parts inside Opening the unit is not recommended and will violate the New Focus warranty 14 Operation NEW FOCUS Inc Characteristics Specifications The specifications for all three models in a comparison format are shown in the table below The primary performance difference between the three units is determined by the use of a VCO based versus a synthesizer based frequency source
15. ly for the EOM and driver to be this far off resonance as the VCO tuning range of the option A units is explicitly limited to 5 of the center frequency and the option B and C units are factory tuned to be at the EOM center frequency EO Modulator Driver and Source Characteristics 17 Figure 5 Typical response of the Reflected RF Monitor port Figure 6 Nominal RF Out in Vpp versus AM modulation input voltage Output level knob is turned fully counter clockwise 18 Characteristics s CD 50 kHz 100 kHz 1 MHz 10 MHz 100 MHz 1 GHz m 2 GHz Reflected Power Monitor Vdc 0 0 1 0 2 0 3 04 05 06 07 08 Reflected Signal Vrms Figure 6 shows the typical transfer function of the AM modulation input item 12 Figure 1 This input mimics the front panel output level knob with a 0 to 5 volt input range This analog input is designed to operate with the output level knob set to minimum fully CCW ashi a N O Nominal Output Vpp O N A O Co 0 05 1 15 2 25 3 35 4 45 AM Modulation Voltage Vmod V Figure 7 shows the input return loss of the external oscillator input item 5 Figure 1 for the source selector switch item 4 Figure 1 in both positions The reflection is less than 9 dB when the external oscillator input is enabled but one should note that it is slightly reflective when disabled NEW FOCUS Inc Figure 7 Inp
16. on B this is a RS 232 DB 9 female connector For Option C this is a parallel port DB 9 male connection This port allows the synthesizer frequency to be adjusted from a computer 8 Operation NEW FOCUS Inc Figure 1 Front and rear panel of the 3363 A RF Out Ext Osc Se LY Reflected RF Ext Osc Input Monitor 9 ee EO Modulator Driver amp Source NEW FOCUS Made in USA TTL Enable Internal Source EO Modulator Driver and Source Operation 9 Figure 2 Front and rear panel of the 3363 B and 3363 C l D Ext Ose Ext Ose Input Power Model 3363 any 30 oe EO Modulator Driver amp Source L NEW FOCUS Made in USA Quick Start Instructions The unit is ready to use straight out of the box Check that the power switch 1 is off and that the RF out on off switch 3 is out Plug the line power cord into the back of the unit 14 and into a wall socket Connect your EOM to the RF out port 9 using the supplied 48 long SMA to SMA cable and secure both ends properly standard SMA torque is 9 in lbs Turn power on to the unit by pressing the toggle 1 It will take 2 3 seconds for the power supply and thus front panel indicator 2 to come on Set the output level knob 8 to the most counterclockwise position for minimum output Press the RF out on off button 3 to turn on the power amplifier Turn up the level knob 8 until you see modulation For the Model 33
17. s 100 240VAC 100 240VAC 100 240VAC 50 60 Hz 50 60 Hz 50 60 Hz 1 0 0 5 A 1 0 0 5 A 1 0 0 5 A Performance Details In Figure4 below we show a typical plot of the output voltage providedto the EOM versus the angleof the output level knob item 8of Figure 1 The substantially flat portions at either endof the knob travel act to indicate the unit isproviding either minimum or maximum available output This curve shows performance of a typical unit the exact voltage and angle will vary slightly from unit to unit depending upon option andfrequency chosen 16 Characteristic s NEW FOCUS Figure 4 Output of RF Out in Vpp versus Output Level knob angle NS Nominal Output Vpp 0 50 100 150 200 250 300 Knob angle deg Figure 5 illustrates the typical response of the reflected RF monitor port item 10 Figure 1 for several frequencies The typical slope is 16 V of reflected port signal for every RMS volt reflected back from the EOM Note that this port monitors power reflected back from the load typically an EOM and not the forward power transmitted to the load For reference the coupler that captures the backreflected power has 20 dB typical coupling to the coupled port The return loss or S11 of our EOMs varies by model and by frequency but a typical value of S11 is less than 25 dB on resonance This value rises to nearly 0 dB highly reflective far off resonance Note that it is very unlike
18. the EOM or NEW FOCUS Inc power amplifier Note that when this button is off there may still be some signal leaking through the attenuation ranges from 16 30 dB depending upon option and frequency chosen 4 Internal Source External Oscillator switch When in the up position Int Source the internal VCO or synthesizer is used to produce the output When in the down position an external frequency source can be used 5 External oscillator input SMA female When the switch 4 is in the down Ext Osc position this input provides the oscillation source for the EOM amplifier 6 Frequency adjust knob Option A only Adjusts the frequency of the VCO Factory adjustment is typically 5 around the user specified center frequency This is a one turn potentiometer 7 Lock Free switch option A only When down in the free position the frequency adjust knob 6 acts normally to adjust the output frequency of the unit When up in the lock position the unit tracks the resonance of the EOM 8 Output Level knob Adjusts the output power delivered by the driver from approximately 3 dBm on the low end to approximately 30 dBm on the high end 9 RF output The high level RF signal provided to the modulator This must be connected to the EOM or a 50 ohm load when the RF enable 3 switch is on or damage may occur to the amplifier 10 Reflected RF monitor This provides a DC voltage proportional to the RMS
19. ut return loss of external oscillator input port for both internal and external oscillator switch settings Ext Source Input S11 dB Ext sc nt Source 0 900 1000 1900 2000 2500 Frequency MHz Figure 8 shows the output of the VCO aux output for the 3363 A Option item 13 in Figure 1 ona spectrum analyzer with the system running free in the top spectrum and locked in the bottom spectrum Lock Free switch is item 7 in Figure 1 In both figures the horizontal scale is 50 kHz division and the vertical scale is 10 dB division The effect of the locking circuit on the output spectrum is to broaden it by approximately 40 kHz the locking dither frequency is approximately 900 Hz Since the resonance of most models of EOM is greater than 1MHz the dither of the locking circuit should have no direct effect on the modulation depth EO Modulator Driver and Source Characteristics 19 Figure 8 Frequency spectrum from 3363 A with locking circuit disabled left and enabled right The horizontal scale is 50 kHz per division and the vertical scale is 10 dB per division 20 Characteristics ATTEN 30 dB MKR 71 17 dBm RL 20 0 dBm 10 dB 151 8250 MHz sowe MHz Mia teh iki WA NON WOW START 151 7500 MHz STOP 152 2500 MHz RBW 3 0 kHz VBW 3 0 kHz SWP 140 ms ATTEN 30 dB MKR 73 33 dBm RL 20 0 dBm 10 dB 151 8250 MHz
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