TIMS Modules Manual
Contents
1. AC ANALOG INPUT X ANALOG INPUT Qlanaocoutur FRONT PANEL BLOCK DIAGRAM USE The input coupling switch may be used to remove input DC components by switching to AC coupling It should be noted that any DC component in the output will not be removed The k factor a scaling parameter associated with four quadrant multipliers is approximately one half It is defined with respect to the OUTPUT from the module and may be measured ex perimentally BASIC SPECIFICATIONS Bandwidth approx 1MHz Characteristic k X t Y t k approx 1 2 PARAMETERS TO NOTE linearity k factor carrier leak phase response DC off set performance as a squarer frequency response conversion gain as a de modulator TIMS 301 User Manual 12 PHASE SHIFTER The PHASE SHIFTER introduces a phase shift between its input and output This phase shift is adjustable by the user The frequency range of operation can be selected by PCB mounted switch BLOCK DIAGRAM PHASE SHIFTER COARSE PHASE ADJUST FINE PHASE ADJUST 180 PHASE CHANGE HI FREQUENCY ANALOG INPUT ANALOG OUTPUT RANGE JLO IN OUT FRONT PANEL PCB VIEW USE This variable PHASE SHIFTER is capable of varying the magnitude of the phase shift through 360 degrees in two steps The 180 degree switch selects the step or region of interest the COARSE and FINE controls are used to then obtain the required phase shift If the input is COS2. 1 1 11 2048 TIMS 301 User Manual 17 BASIC SPECIFICATIONS Input Clock Range TTL 1Hz to 1MHz Analog lt 500Hz to gt 10kHz Number of Sequences 4 pairs Sequence Lengths 25 28 28 aM Sync indicates start of sequence PARAMETERS TO NOTE sequence distribution noise generation using pseudorandom sequences TIMS 301 User Manual 18 TRUNKS PANEL The TRUNKS PANEL provides inputs and outputs to signals which are transmitted along the OP TIONAL TIMS BUS classroom network The three outputs SIGNAL 1 SIGNAL 2 and SIGNAL 3 present signals from the lecturer s master system IN and OUT allow for signals to be respec tively received from and transmitted to a neighboring TIMS system TRUNKS PANEL SIGNALS 1 2 amp 3 COME FROM THE MASTER TIMS SYSTEM IF TRUNKS IS CONNECTED INCOMING SIGNAL FROM ADJACENT STUDENTS TIMS SYSTEM IF TRUNKS IS CONNECTED OUT SENDS A SIGNAL TO THE NEXT STUDENTS TIMS SYSTEM IF TRUNKS IS CONNECTED FRONT PANEL USE Note that the TRUNKS PANEL is a module that differs from the TIMS front panel color code and alignment conventions Though the inputs and outputs are YELLOW analog either analog or digital signals may be used Also the signal input OUT which accepts a signal that is to be transmitted to a neighbor ing TIMS system is on the right hand side BASIC SPECIFICATIONS when TIMS TRUNKS is installed Master Channels 3 SIGNAL 1 SIGNA
3. GAIN CONTROL ANALOG INPUT OF SECOND AMPLIFIER FRONT PANEL BLOCK DIAGRAM USE These buffers may be used to amplify small signals or attenuate large signals Each amplifier has its own gain control on the front panel Care should be taken to ensure that later modules are not overloaded due to excessive gain Overload will not cause any damage but it means non linear operation which is to be avoided in analog systems If overload occurs turn the gain control counter clockwise BASIC SPECIFICATIONS Bandwidth DC to approx 1MHz Gain 0 to 10 TIMS 301 User Manual 6 DUAL ANALOG SWITCH Two identical analog switches are controlled by digital TTL level signals The outputs of the two switches are added internally and presented at the output of the module DUAL ANALOG SWITCH ANALOG INPUT 1 IN 1 TTL CONTROL FOR INPUT 1 CONTROL 1 TTL CONTROL FOR INPUT 2 CONTROL 2 ANALOG INPUT 2 OUTPUT FRONT PANEL USE IN 1 CONTROL 1 OUTPUT CONTROL 2 IN 2 J LA BLOCK DIAGRAM Each switch may be closed independently by a TTL HIGH at the respective control input The switch outputs are combined internally and are presented at the common output socket Open circuit voltage gain between each input and the module output is unity when the switch is closed BASIC SPECIFICATIONS Analog Input Bandwidth gt 300kHz Maximum CONTROL clock gt 100kHz CONTROL Input Levels TTL only Maximum Anal
4. TIMS 301 USER MANUAL Telecommunications Instructional Modelling System TIMS 301 USER MANUAL Author Alfred Breznik and Carlo Manfredini Issue Number 1 6 October 2004 All specifications are subject to change without notice Published by EMONA INSTRUMENTS PTY LTD a c n 001 728 276 86 Parramatta Road Camperdown NSW 2050 Sydney AUSTRALIA web www tims com au telephone 61 2 9519 3933 fax 61 2 9550 1378 Copyright C 1988 2004 Emona Instruments Pty Ltd and its related entities All rights reserved No part of this publication may be reproduced distributed or translated in any form or by any means including any network or Web distribution or broadcast for distance learning or stored in any database or in any network retrieval system without the prior written constent of Emona Instruments Pty Ltd For licensing information please contact Emona Instruments Pty Ltd The TIMS logo FSA is a registered trademark of Emona TIMS Pty Ltd Printed in Australia CONTENTS Part TIMS INTRODUCTION TIMS OVERVIEW SYSTEM CONVENTIONS Front Panel Sockets Plug in Modules Labelling Basic Modules List Basic Specifications Part II BASIC MODULES USER INSTRUCTIONS Adder Audio Oscillator Buffer Amplifiers Dual Analog Switch Frequency and Event Counter Headphone Amplifier and 3kHz LPF Master Signals Multiplier Phase Shifter Quadrature Phase Splitter Scope Selector Sequence Generator Trunks Panel Tuneab
5. CARRIER signals are 100kHz which for modelling purposes is sufficiently far from the audio channel bandwidth of 3kHz The SAMPLE CLOCK of 8 3kHz which may be used to sample bandwidth limited 3kHz audio message signals MESSAGE provides an audio frequency signal which is synchronized to a sub multiple of the carrier to enable text book like displays of simple modulation schemes to be achieved The five signals are derived from a master crystal oscillator resulting in low frequency drift Their frequencies are fixed internally The output levels are also fixed To vary the amplitude the sig nals may be applied to the neighboring buffers The analog signals are sinusoidal in shape having a distortion of less than 0 1 Digital signals are all standard TTL level with rise times of better than 80nsec TIMS 301 User Manual 10 BASIC SPECIFICATIONS Output Frequencies 100kHz carrier 8 333kHz sample clock 2 083kHz audio carrier sub multiple Output Levels 4V pk pk analog TTL level digital Distortion lt 0 1 analog outputs only PARAMETERS TO NOTE short term frequency stability relative phase of quadrature outputs harmonic content TIMS 301 User Manual 11 MULTIPLIER Two analog input signals X t and Y t may be multiplied together The resulting product is scaled by a factor of approximately 1 2 so that with standard level inputs later stages are not overloaded MULTIPLIER INPUT COUPLING SWITCH
6. is scaled amplified by the front panel GAIN control A DC voltage can be added to Vin inter nally thus setting the start or CENTER FREQUENCY fo The CENTER FREQUENCY is defined as the VCO output frequency when no voltage is applied to the Vin connector The Vin input is internally tied to ground if no signal is applied The Vin OVERLOAD LED is lit when the sum of these voltages scaled Vin plus CENTER FRE QUENCY DC offset exceed the oscillator s internal operating limits Decrease the GAIN turn counter clockwise and or shift the CENTER FREQUENCY fo to extinguish the LED The frequency range switch selects between the HI or carrier band and the LO or audio band Both sinewave and digital outputs are available TIMS 301 User Manual 26 SPECIAL VCO OPERATION FINE FREQUENCY CONTROL In some applications fine control may be required over the output frequency of the VCO This may be easily achieved by following these four steps MODULES REQUIRED VCO and VARIABLE DC STEP 1 Set the VARIABLE DC module s output close to zero marker knob at 12 o clock position STEP 2 1 Turn the GAIN control of the VCO to zero fully counter clockwise STEP 2 2 Now turn the GAIN control up clockwise just a little only a few degrees STEP 3 Set the VCO module s output frequency as close as possible to the frequency of interest Use the frequency adjust knob fo Use the FREQUENCY COUNTER to measure the VCO s output
7. CONTROL OUTPUT i AC COUPLED DIGITAL CLOCK TTL LEVEL OUT A ty Bi E t tp KI tp DELAY ty WIDTH TIMING DIAGRAM FRONT PANEL USE A digital TTL level signal is applied to the CLK input The GENERATOR then outputs one or two pulses depending upon the operating mode selected Use the PCB mounted MODE switch to select either SINGLE or TWIN operating mode TWIN MODE TWIN mode is used when two sequential pulses are needed Two equal width positive pulses oc cur as a result of each CLK signal positive edge Pulse Q1 always occurs before pulse Q2 The width of both pulses is controlled by the front panel WIDTH control The DELAY control varies the spacing between the two pulses Note that TWIN mode will only accept CLOCK input signals of up to 50kHz depending upon front panel settings If WIDTH and DELAY have been incorrectly set causing anomalous operation the ERROR LED will be lit To eliminate the error reduce DELAY and then WIDTH by turning counter clock wise TIMS 301 User Manual 21 SINGLE MODE SINGLE mode is used to obtain a train of equal width pulses from any TTL level signal Equal width positive pulses occur at Q1 output as a result of each CLK signal positive edge The width of the pulses is controlled by the front panel WIDTH control Q2 simultaneously outputs the compliment of Q1 The DELAY control is not used in this mode Note that Q1 includes both a TTL level and an AC coupled output pulse BASIC SPECIFI
8. frequency STEP 4 Finally patch the VARIABLE DC module s output to the VCO module s frequency control input Vin with a standard patching lead FINE FREQUENCY CONTROL of the VCO module is now achieved by turning the VARIABLE DC module s voltage control knob FSK USE A PCB mounted slide switch selects between FSK and VCO modes of operation The two out put frequencies FSK1 and FSK2 MARK and SPACE are set by varying the PCB mounted fin ger adjustable trimmers As in VCO mode the frequency range switch selects between the HI or carrier band and the LO or audio band The digital data input accepts only TTL level signals Both sinewave and digital outputs are available GAIN and CENTER FREQ fo controls and the Vin connector are not used in the FSK mode BASIC SPECIFICATIONS VCO MODE Frequency Ranges 1 5kHz lt LO lt 17kHz sinewave and TTL lt 300Hz with external input voltage Vin 70kHz lt HI lt 130kHz sinewave and TTL Input Voltage 3V lt Vin lt 3V Overload limit indication LED Vvco gt _ 3V Vvco is the internal voltage finally applied to the VCO circuitry GAIN G Vin 1 lt G lt 2 Center Frequency Voltage Range 3V lt Vic lt 3V Vic is a DC voltage added INTERNALLY to G Vin FSK MODE Frequency Ranges 1 5kHz lt FSK1 Lo lt 9kHz 500Hz lt FSK2 Lo lt 4kHz 80kHz lt FSK1 Hi lt 200kHz 20kHz lt FSK2 H lt 120kHz Data Input TTL level message TIMS 301 User Manual 27 60kHz
9. 0 mm Plug in Card Bus Connectors 64 way 2 row Eurocard MODULES Specifications for each module are listed in the following pages TIMS 301 User Manual 3 ADDER Two analog input signals A t and B t may be added together in adjustable proportions G and g The resulting sum is presented at the output G GAIN CONTROL FOR INPUT A A gt GA gB g GAIN CONTROL FOR INPUT B ANALOG INPUT O ANALOG OUTPUT B GA gB FRONT PANEL BLOCK DIAGRAM USE Care must be taken when adjusting the gains to avoid overloading the following modules Over loading will not cause any damage but it means non linear operation which is to be avoided in analog systems The ADDER is capable of delivering a signal well in excess of the standard refer ence level 4V pk pk given a standard level input The ADDER can also be used as a normal amplifier by using only one input and turning the gain of the other input to minimum It is not necessary to ground the unused input Note that gains G and g are negative All inputs and outputs are DC coupled BASIC SPECIFICATIONS Gain Range 0 lt G lt 2 0 lt g lt 2 Bandwidth approx 1MHz Output DC Offset lt 10mV open circuit inputs PARAMETERS TO NOTE maximum output level linearity polarity inverting phase shift TIMS 301 User Manual 4 AUDIO OSCILLATOR The AUDIO OSCILLATOR is a low distortion tuneable frequency sinewave source with a fre quency range from 500
10. CATIONS TWIN MODE Clock Frequency Range lt 50kHz Pulse WIDTH 3us lt tw lt 25us Pulse DELAY Q2 Q1 10us lt ta lt 120us Error Indication 2tw td gt tcLK SINGLE MODE Clock Frequency Range lt 200kHz Pulse WIDTH 3us lt tw lt 25us TIMS 301 User Manual 22 UTILITIES MODULE The Utilities Module houses 4 independent functional blocks i A signal COMPARATOR with TTL output and CLIPPER with bipolar output for squaring analog waveforms The COMPARATOR s threshold level may be set as required by applying a DC volt age to the REF input The CLIPPER s gain may be set by adjusting DIP switches SW1 and SW2 ii Precision halfwave RECTIFIER iii Simple diode and single pole audio range RC Lowpass Filter Swi sw2 iv Single pole audio range RC Lowpass Filter BIPOLAR UTILITIES OUT ANALOG REFERENCE CLIPPER Ai Dg TTL INPUT BIPOLAR OUTPUT our REF CLIPPER ANALOG SIGNAL COMPARATOR RER INPUT TTL OUTPUT COMPARATOR IN gt OUT ANALOG INPUT ANALOG OUTPUT gt PRECISION ANALOG INPUT ANALOG OUTPUT me DIODE LPF IN gt eur RC ANALOG INPUT ANALOG OUTPUT Ox IN OUT RC FRONT PANEL BLOCK DIAGRAM USE COMPARATOR The COMPARATOR will square any analog signal and provide a standard TTL level output The switching threshold level is determined by the voltage level applied to the REF input NOTE For correct COMPARATOR operation the REF input must never be left unconnected The REF in
11. Hz to 10kHz Three outputs are provided Two outputs are sinusoidal with their signals in quadrature The third output is a digital TTL level signal AUDIO OSCILLATOR INPHASE SR ANALOG cos at SYNC cos wt OUTPUT 20 sin ot FREQUENCY ADJUST TTL TTL LEVEL OUTPUT SQUARER QUADRATURE ANALOG OUTPUT FRONT PANEL BLOCK DIAGRAM USE The frequency of each of the three outputs is the same and is varied by the front panel A f con trol Both the in phase and quadrature analog output signals have fixed amplitude Their shape is sinusoidal having a distortion of less than 0 1 The AUDIO OSCILLATOR may be synchronized to an external periodic signal by connecting such a signal to the front panel SYNC input A signal of about 1 volt peak is adequate for this purpose For synchronization to be achieved the AUDIO OSCILLATOR must be manually tuned to within a few percent of the frequency to which synchronization is desired BASIC SPECIFICATIONS Frequency Range 300Hz to 10kHz Analog Output Level 4V pk pk Distortion lt 0 1 analog outputs only Digital Output TTL level PARAMETERS TO NOTE frequency range relative phase of outputs amplitude stability with frequency range harmonic content short term stability synchronizing characteristic TIMS 301 User Manual 5 BUFFER AMPLIFIERS Two independent variable gain amplifiers are provided BUFFER AMPLIFIERS GAIN CONTROL ANALOG INPUT OF FIRST AMPLIFIER
12. L 2 and SIGNAL 3 Master Channel Bandwidth 700kHz typ ac coupled Local Channels 2 IN brings the incoming signal FROM an adjacent TIMS OUT port OUT carries the outgoing signal TO the other adjacent TIMS IN port Local Channel Bandwidth 350kHz typ ac coupled TIMS 301 User Manual 19 TUNEABLE LPF The cutoff frequency of this LOWPASS FILTER can be varied using the TUNE control Two frequency ranges WIDE and NORMAL can be selected by a front panel switch The GAIN control allows signal amplitudes to be varied if required TUNEABLE LPF CLK for TLPF modules V1 to V3 CLK 880 f 34B NORMAL CLK 360 f 3aB WIDE CLK for TLPF modules V4 CLK 100 f 3aB NORMAL amp WIDE CUT OFF FREQUENCY ADJUST GAIN ADJUST FREQUENCY ii Rir OUT RANGE SELECT ON TUNEABLE ANALOG INPUT ANALOG OUTPUT IN OUT BLOCK DIAGRAM USE FRONT PANEL This lowpass filter has an elliptic filter characteristic The stopband attenuation is typically 50dB and passband ripple is approximately 0 5dB The GAIN control is used to vary the amplitude of the output signal Care should be taken to avoid overloading saturation Two frequency ranges are provided NORMAL range provides more precise control over the lower audio band used for telecommunications message channels The WIDE range expands the filters range to above 10kHz The CLK output provides an indication of the filter s cutoff frequency BASIC SPECIFICATIONS for TLPF m
13. LOWPASS FILTER An elliptic lowpass filter is provided with a cutoff point of approximately 60kHz The input signal amplitude can be adjusted with the gain control 6OkHz LPF mw ANALOG INPUT O ANALOG OUTPUT IN OUT FRONT PANEL BLOCK DIAGRAM USE The 60kHz LPF allows carrier signals to be removed from a given signal spectrum For example as the lowpass filter for envelope detector applications The GAIN control allows input signals to be attenuated to avoid overloading the filter BASIC SPECIFICATIONS Cutoff Frequency approx 60kHz Passband Gain variable 0 to 5 approx Stopband Attenuation 50dB typ Passband Ripple 0 1dB typ PARAMETERS TO NOTE corner point response shape passband ripple phase shift out of band attenuation TIMS 301 User Manual 28
14. MS modules conform to the following mechanical and electrical conventions A FRONT PANEL SOCKETS Signal interconnections are made via front panel 4mm sockets Sockets on the LEFT HAND SIDE are for signal INPUTS All inputs are high impedance typically 56k ohms Sockets on the RIGHT HAND SIDE are for signal OUTPUTS All outputs are low impedance typically 330 ohms YELLOW sockets are only for ANALOG signals ANALOG signals are held near the TIMS standard reference level of 4V pk pk RED sockets are only for DIGITAL signals DIGITAL signals are TTL level 0 to 5 V GREEN sockets are all common or system GROUND Note that input and output impedances are intentionally mismatched so that signal connections may be made or broken without changing signal amplitudes at module outputs B PLUG IN MODULES Any plug in module may be placed in any of the 12 positions of the upper rack All modules use the back plane bus to obtain power supply only the DSP modules not part of the BASIC SYS TEM use the bus to transfer signals The modules are designed so that they may be plugged in or removed at any time without turning off the system power The modules are not locked into position and may need to be held while interconnecting leads are removed C LABELLING All modules are identified as to the function they perform Inputs outputs controls and switches are labelled so that a student who has had only a brief in troduction to TIMS c
15. TCHING LPF OUTPUT TO n our AMPLIFIER INPUT AMPLIFIER GAIN ADJUST k AMPLIFIER AND HEADPHONE FILTER INPUT OUTPUT LOWPASS FILTER OUTPUT FRONT PANEL BLOCK DIAGRAM USE This module serves as an electro acoustic interface between the audio signals within the system and the user Included within the HEADPHONE AMPLIFIER module is an independent LOW PASS FILTER with a 5th order elliptic characteristic The filters cutoff frequency is 3kHz stop band attenuation is 50dB and passband ripple is 0 2dB BASIC SPECIFICATIONS AUDIO AMPLIFIER Bandwidth lt 100kHz THD 0 2 RL 80hms P 125mW Maximum Gain 20 Maximum Output Power 500mW Output Impedance 8 ohms LOWPASS FILTER Cutoff Frequency 3kHz Stopband Attenuation 50dB Passband Gain approx 1 Passband Ripple 0 2dB PARAMETERS TO NOTE filter corner point filter shape passband ripple out of band attenuation amplifier distortion TIMS 301 User Manual 9 MASTER SIGNALS Five synchronized analog and digital signals are available ranging from 2kHz to 100kHz The function and frequency of each signal is indicated on the front panel MASTER SIGNALS sin ct QUADRATURE ANALOG CARRIER SIGNAL cos at fO0kH2 0O INPHASE ANALOG CARRIER SIGNAL TTL TTL LEVEL CARRIER SIGNAL TTL TTL 8 3kHz SAMPLE TTL LEVEL CLOCK TTL 100kHz sin ut v e Q ANALOG SIGNAL sin yt FRONT PANEL BLOCK DIAGRAM USE Signals are labelled as follows
16. VARIABLE DC module is a stable bipolar DC source VARIABLE DC DC VOLTAGE CONTROL DCV Q pc outeut DC GROUND GND REFERENCE FRONT PANEL BLOCK DIAGRAM USE The DC voltage output varies from about 2 5V when the control is fully counter clockwise through zero to 2 5V when control is turned fully clockwise If greater resolution or wider range is required then one of the BUFFER AMPLIFIERS can be used in conjunction with the VARIABLE DC module BASIC SPECIFICATIONS Voltage Range 2 5V DC Short term Stability lt 2mV hr Resolution approx 20mV Output Current lt 5mA TIMS 301 User Manual 25 VCO The Voltage Controlled Oscillator module functions in two modes either as a VOLTAGE CON TROLLED OSCILLATOR with analog input voltage or as an FSK GENERATOR with digital input Both modes have two frequency ranges of operation which are selected by a range switch The VCO frequency and input sensitivity can be controlled from the front panel Vin VCO OUT FSK DATA INPUT EIEL VEO MODE TTL LEVEL 2 UUT SET SENSITIVITY TTL DATA VCO FSK OF INPUT CONTROL VOLTAGE Vin OVERLOAD FSK MODE INDICATION LED SET CENTER BLOCK DIAGRAM FREQUENCY FREQUENCY RANGE SELECTION CONTROL VOLTAGE ANALOG OUTPUT INPUT Vin sin wt FSK1 FSK2 Q FSK VCO O FRONT PANEL 2 O OO PCB VIEW VCO USE STANDARD VCO OPERATION The VCO output frequency is controlled by an analog input voltage The input voltage Vin
17. WORK 2 ANALOG OUTPUT FROM NETWORK 2 FRONT PANEL BLOCK DIAGRAM USE The QUADRATURE PHASE SPLITTER consists of two wideband phase shifting networks The networks phase responses vary with frequency in a complimentary manner giving a 90 degree phase difference between the outputs over a wide frequency range In communications the most important application is the generation and demodulation of Single Sideband by the phasing method BASIC SPECIFICATIONS Frequency Range 200Hz to 10kHZz typically Phase Response 90 degrees between outputs given the same input signal to both networks PARAMETERS TO NOTE Phase error from 90 degrees This may be measured directly difficult or calculated from side band suppression measurements TIMS 301 User Manual 15 SCOPE SELECTOR OSCILLOSCOPE DISPLAY SELECTOR The OSCILLOSCOPE DISPLAY SELECTOR allows 2 of 4 different signals to be viewed simultane ously on a2 channel oscilloscope A third input labeled TRIG is ideal for connecting a trigger sig nal to the oscilloscope s external trigger input SCOPE SELECTOR INPUT SELECTOR CH1 INPUT A HCH1 OUTPUT CH1 INPUT B CONNECT TO TRIGGER INPUT Qne SCOPE TRIGGER INPUT INPUT SELECTOR CH2 INPUT A CH2 INPUT B FRONT PANEL USE A a ee CH1 Be e TRIG A or Wage area CH2 DIAGRAM Connection to the oscilloscope is via BNC sockets Inputs are standard 4mm sockets Although th
18. an use the modules without needlessly referring back to this USER MANUAL It should be noted that no variable controls have calibration marks This is intentional as the phi losophy behind TIMS is that students setup and adjust systems by observing and measuring sig nals This assists the student in gaining a much greater understanding feel and insight into the operation of a communications implementation TIMS 301 User Manual 2 D BASIC MODULE LIST Below are listed all the BASIC SYSTEM MODULES FIXED modules are located in the lower rack while PLUG IN modules can be positioned anywhere in the upper rack Adder plug in Audio Oscillator plug in Buffer Amplifiers fixed Dual Analog Switch plug in Frequency and Event Counter fixed Headphone Amplifier and 3kHz LPF fixed Master Signals fixed Multiplier plug in Phase Shifter plug in Quadrature Phase Splitter plug in Scope Display Selector fixed Sequence Generator plug in Trunks Panel fixed Tuneable LPF plug in Twin Pulse Generator plug in Utilities Module plug in Variable DC fixed Voltage Controlled Oscillator plug in 60kHz Lowpass Filter plug in BASIC SPECIFICATIONS POWER SUPPLY Input 120 127 220 or 240V AC 47Hz to 63Hz Output 15V 2 2A DC 15V 2 2A DC Protection short circuit overload thermal Regulation 0 2 PHYSICAL Case Dimensions 490 W x 330 D x 310 H mm System Weight 10kg Plug in Card Dimensions 160 x 10
19. e input sockets are YELLOW analog either analog or digital signals may be examined TIMS 301 User Manual 16 SEQUENCE GENERATOR PSEUDORANDOM SEQUENCE GENERATOR Using a common external clock signal the sequence generator outputs two independent pseudorandom sequences X and Y A SYNC output is provided which is coincident with the start of the sequences The sequences may be stopped and restarted at any time via front panel controls Sequences X and Y are available as either standard TTL or analog level output SEQUENCE GENERATOR RESET ANALOG OUTPUT PUSH BUTTON TTL LEVEL RESET ANALOG OUTPUT Y BEGINNING OF SEQUENCE SYNCH RESET eine X SEQUENCE TTL OUTPUT Y SEQUENCE SYNC ANALOG CLOCK TTL CLOCK TTL OUTPUT Y FRONT PANEL BLOCK DIAGRAM USE An external clock signal must be provided to operate the SEQUENCE GENERATOR This may be sinusoidal or TTL separate input sockets are used The sequences may be stopped at any time by either depressing the RESET button or applying a TTL HI signal to the RESET input To restart the sequences from the beginning release the RESET button or apply a TTL LO to the RESET input The length of the sequences may be selected by a PCB mounted dip switch Four independent sequence pairs are available from lengths of 25 to 211 The sequences are selected as follows DIP SWITCH CODE n SEQUENCE LENGTH 2 msb 0 0 5 32 0 1 8 256 1 0 8 256
20. le LPF Twin Pulse Generator Utilities Module Variable DC Voltage Controlled Oscillator 60kHz Lowpass Filter TIMS INTRODUCTION TIMS OVERVIEW TIMS is a telecommunications modelling system It models mathematical equations representing electrical signals or block diagrams representing telecommunications systems TIMS is primarily a hands on rather than demonstration style teaching system which combines both the theoretical and practical aspects of implementing systems We are confident that TIMS will provide the student with a clearer understanding of the concepts behind telecommunications theory Physically TIMS is a dual rack system The top rack accepts up to 12 Eurocard sized compat ible black boxes or modules The lower rack houses a number of fixed modules as well as the system power supply The modules are very simple electronic circuits which function as basic communications build ing blocks Each module fixed or plug in has a specific function functions fall into four general categories Signal Generation oscillators etc Signal Processing multipliers filters etc Signal Measurement frequency counter Digital Signal Processing TMS320C50 based DSP amp Advanced Modules are not included in the BASIC TIMS 301 SYSTEM Modules are patched together via the front panel sockets using interconnecting leads to model the system under investigation TIMS 301 User Manual 1 SYSTEM CONVENTIONS All TI
21. odules V1 to V3 Filter Ranges 900 Hz lt NORMAL lt 5 kHz and 2 0 kHz lt WIDE lt 12 kHz continuously variable over each range Filter Order 7th order Elliptic Stopband Attenuation gt 50dB and Passband Ripple lt 0 5dB BASIC SPECIFICATIONS for TLPF modules V4 Filter Ranges 200 Hz lt NORMAL lt 5 kHz and 200 Hz lt WIDE lt 12 kHz continuously variable over each range Filter Order 5th order Elliptic Stopband Attenuation gt 50dB and Passband Ripple lt 0 5dB Maximum Input Voltage 5V to 5V TTL level input signal is acceptable PARAMETERS TO NOTE corner point phase shift gain range passband ripple out of band attenuation TIMS 301 User Manual 20 TWIN PULSE GENERATOR TWIN PULSE GENERATOR VERSION 2 0 A positive going edge applied at the CLOCK input causes a positive pulse to occur at the out put terminals There are two operating modes TWIN and SINGLE Only TWIN mode is limited to low frequency CLOCK inputs In TWIN mode Q1 outputs the leading pulse and Q2 outputs the delayed pulse The time be tween pulses Q1 and Q2 can be varied as can the pulses widths In SINGLE mode only Q1 outputs a positive going pulse while Q2 outputs the inverse of Q1 The pulse width can be varied TWIN PULSE GENERATOR CLOCK meer PULSE Q Tl DELAYED PULSE Q ERROR LED INDICATES IF 2tw tb gt tcLk BLOCK DIAGRAM PULSE WIDTH CONTROL CLK OUTPUT t TTL LEVEL i tek DELAY TIME LEADING PULSE 1 E w
22. og Input Level 8V PARAMETERS TO NOTE switch On Off ratio linearity switching speed analog bandwidth channel cross talk DC off set TIMS 301 User Manual 7 FREQUENCY COUNTER The TIMS counter is an 8 digit 10MHz frequency and event counter FREQUENCY COUNTER COUNTS ANALOG O 1s GATE TIME O COUNTS 6 TTL TTL ENABLE BASIC SPECIFICATIONS 1 OVERflow indication LED 2 ANALOG input Bandwidth 40Hz to 1 MHz Sensitivity 250mV typically 100kHz Maximum input 12V 3 TTL Input Bandwidth DC to 10MHz Input TTL level signals only 4 TTL ENABLE may be used to gate the TTL input signal Specifications are same as for the TTL input 5 Mode and Range rotary switch Frequency counter mode Gate time selection of 0 1s 1s or 10s with reading in kHz Event counter mode displays number of pulses counted since the last RESET 6 RESET Push Button resets the count of the Event Counter to zero 7 kHz LED is lit when counter is in FREQUENCY COUNTER mode 8 8 digit 7 segment display of frequency or pulse counts maximum display 99999999 9 COUNTS LED is lit when counter is in EVENT COUNTER mode TIMS 301 User Manual 8 HEADPHONE AMPLIFIER and 3kHz LPF The HEADPHONE AMPLIFIER is a wideband variable gain audio amplifier which will drive stand ard 80hm headphones or a speaker An independent 3kHz LOWPASS FILTER may be switched in before the audio amplifier if required HEADPHONE AMPLIFIER LPF SELECT FOR SWI
23. put may be connected to GROUND VARIABLE DC or any other signal source CLIPPER The CLIPPER will amplify any analog TIMS level signal and then clip the amplitude of the ampli fied signal to a fixed level of approximately _1 8V The clipping action is performed by stand ard small signal diodes NOTE The REF input is NOT used by the CLIPPER TIMS 301 User Manual 23 Adjusting the gain of the CLIPPER determines whether the clipping action is SOFT MEDIUM or HARD The following table UTIL 1 relates DIP switch settings to CLIPPER gains and clip ping action CLIPPING GAIN DIP SWITCH SETTINGS ACTION approx SW1 both a amp b SW2 both a amp b SOFT x0 8 ON ON OFF OFF MEDIUM x8 OFF OFF OFF OFF HARD x40 OFF OFF ON ON not applicable ON ON ON ON Table UTIL 1 CLIPPER gain settings DIP switches SW1 and SW2 will be found in the middle of the UTILITIES module s circuit board NOTE Both halves bits of each switch must be in the SAME position at all times BASIC SPECIFICATIONS COMPARATOR Operating Range gt 500kHz TTL Output Risetime 100nsec typ CLIPPER Operating Range gt 500kHz Output Level 1 8Vpk typ Adjustable Gains 3 steps x0 8 x8 and x40 approx RECTIFIER Bandwidth DC to 500kHz approx DIODE amp LPF LPF 3dB 2 8kHz approx RC LPF LPF 3dB 2 8kHz approx TIMS 301 User Manual 24 VARIABLE DC The
24. ut then the output is COS ut amp where lies between 0 and 180 degrees Although the PHASE SHIFTER will operate from a few hertz up to 1MHz it has been optimized to operate in the neighborhood of two frequencies around 100kHz in the HI range and around 2kHz in the LO range A PCB mounted switch is used to select the frequency range The open circuit gain through the PHASE SHIFTER is essentially unity for all phases but note that the amount of phase shift is a function of frequency This is NOT a wideband phase changer thus all the frequency components of a complex signal s spectra are not shifted by the same phase TIMS 301 User Manual 13 BASIC SPECIFICATIONS Bandwidth lt 1MHz Frequency Range HI approx 100kHz LO approx 2kHz For 0 to 360 degree range of phase shift The phase shift range increases i e resolution decreases as the input frequency increases Coarse approx 180 degrees shift Fine approx 20 degrees shift PARAMETERS TO NOTE Variation of phase change with frequency change TIMS 301 User Manual 14 QUADRATURE PHASE SPLITTER When the same analog signal is applied to both inputs the two output signals will differ in phase by 90 degrees The phase splitter networks are wideband typically covering the range from 200HZ to 10kHz QUADRATURE PHASE SPLITTER cos ut renee b 90 error ANALOG INPUT TO NETWORK 1 ANALOG OUTPUT cosi FROM NETWORK 1 ANALOG INPUT TO NET
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