Gould os4001-outputunitmanual 电路图.pdf

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1、054001 OUTPUT UNIT Instruction Manual -GOULDADVANCE Telephone 01-5001000 Telegrams AttenuateIlford Telex 263785 RadioFans.CN 收音机爱 好者资料库 SECTION1Introduction3 SECTION5Maintenance12 5.1Fitting the 4001 to the OS400012 SECTION2Specification4 5.2Access13 5.3Fault finding14 SECTION3Operating Instructions

2、5 5.4Setting up Procedure15 3.1General5 3.2Chart recorder speed5 SECTION6Circuit Diagrams and Components 3.3Driving a chart recorder5 Schedules17 3.4The Read-out cycle5 3.5Remote start5SECTION7 Guarantee and Service Facilities21 3.6Function Generation7 3.7Digital Outputs7 ILLUSTRATIONS Fig. 1Typical

3、 read-out cycle6 SECTION4Circuit Description8 Fig. 2Connectionsto back panel socket 7 4.1General8 Fig. 3Block diagram8 4.2D-A Converter9 Fig. 4Data Selector - mechanical 4.3Latches and latch control9 equivalent10 4.4 X-ramp counter9 Fig. 5Clock delay - timing diagram 11 4.5Data Selector9 Fig. 6Inter

4、nal view of 4001 12 4.6Clock delay10 Fig. 7Fixing details 13 Fig. 8Circuit diagram 19 RadioFans.CN 收音机爱 好者资料库 Introduction The 400 I option is designed to be added to a standard OS4000 Digital Storage Oscilloscope to enable the infor- mation in store to be retransmittedin both analogue and digital f

5、orm.Two analogue outputs are provided, and these are intended primarily to drive strip chart and X-V recorders.Channel I and 2 signals are available simultan- eously at a read-out rate which can be varied to suit the chart recorder, with a slowest time of 200 seconds representing the 10 division dis

6、play.In addition, a correspondingX-ramp signal is provided for X-Y recorder use. The unit also incorporatesrelay contacts for pen lift or chart motor control.There is a variable delay between the closing of these contacts and the start of read out which can be preset to allow a chart drive motor to

7、accelerate. .A socket on the rear panel presents the outputinfor- mation in digital form as two eight bit parallel signals for Y and one ten bit parallel signal for the X ramp.Control facilities for remote start and continuousreadout are also provided.The latter can be used for continuous generation

8、 of a recorded transient or frequencyshift of recorded waveforms. RadioFans.CN 收音机爱 好者资料库 Specification ANALOGUEOUTPUTSVia B.N.C. connectors Channels 1 and 2 AmplitudelOOmV per cm of screen height. Bipolar with OV correspondingto middle of screen AccuracyOutput voltage per cm of display3% Output to

9、input voltage (ca!)3% X Ramp Amplitude lOOmV per cm of screen width. Positive ramp resetting to OV Output voltage/cm of displayJ% Output voltage/unittime recorded3% Time outputaccuracy of Y Channel outputs1% (Record to replay ratio) Output ImpedanceCHI, CH2 and X-ramp100H/0.IJ.lF Continuousshort cir

10、cuit protected DIGITALOUTPUTSVia back panel socket All outputstrue binary from open collector T.T.L. buffers 8 bit parallel, negative logic 10 bit parallel, negative logic Y Channelfull scale=9cm of display5% X Rampfull scale=II.3cmof display 5% Channels I and 2 X Ramp Accuracy READ OUT RATE Set on

11、OS4000 time base range switch Range 20sec/cm to200J.ls/cm Read-out bandwidthD.C. -16kHz (-3dB) CONTROLS Front panel start buttonto initiate single read-out cycle. Remote start by T.T.L.lowor contact closure to ground. Section 2 Remote continuousread-out by T.T.L. low or contact closure to ground. De

12、lay between start command and initiation of read-out cycle set by front panel preset control fromI sec. (lOJ.lsec. to lOsec. by internal component change) Front panel access via 4mm sockets to isolated single pole contact which closes from start command to end of read-out cycle Contact rating 200V D

13、.C. 0.5 A D.C. IOWD.C. Isolation 400V max. OUTPUTS Oocks I and 2 Negative T.T.L. pulses, 100nsec. duration marking the change of each digital word. T.T.L. low, commencingat the end of delay, for the durationof the read-out cycle. DIMENSIONS3.75cm extra height to OS4000 WEIGHT570gm extra (l%Ib) to OS

14、4000 approx. ACCESSORIES36 way plugAmpheno157-30360 2 x 4mm plugs Handbook PN 36896 Operation 3.1ANALOGUEOUTPUTS The 4001 may be used to drive strip-chart, T-Y or X-V recorders.Both Y channels are available simultaneously for chart recorders with two pens. Alternatively,the two channels may be repro

15、ducedsequentially on single pen recorders.A synchronisedX-ramp is available to drive X-V recorders as Y-t. Alternatively,the CHI and CH2 outputs can drive an X-Y display directly. The internal contacts can be used to control chart motor and/or pen lift if required. 3.2CHARTRECORDERSPEED The 4001 off

16、ers a very wide range of read-out rates to suit the recorder being used. The rate should be chosen by considering the following: 1)A slow read-out rate, while faithfully reproducing the stored signal, will also show the discrete levels in the output waveform, (there is no dot-joining on the 4001 out

17、puts).A faster read-out rate and chart recorder speed will tend to smooth the output wave form. 2)If too high a read-out rate is chosen, the chart recorder may be unable to follow any large ampli- tude fast change of the signal. This is slew-rate limitation of the recorder. The optimum read out spee

18、d for any particular stored waveform is thus the maximum at which the chart recorder is capable of tracking the signal. This may be determinedby increasing the readout/chart recorder speed each sweep until waveform degrad- ation can be observed. The bandwidth of the outputamplifier is d.c. to 16kHz

19、(-3d B) which is well above the limitationof most chart recorders.However this limitationmay be reached if the outputis required for other purposes when the replay frequencyis a function of recorded waveform and replay rate. (See Function Generator) 3.3DRIVINGA CHARTRECORDER 1)Connect to the CHI, CH

20、2 and X-ramp sockets as reqUired. In single trace operation,the same signal will be present at CHI and CH2 outputs. Set the sensitivity of the chart recorder inputs to accommodate400rn V f.s. on CHI and CH2 and oto 1V on the X-ramp. When the 4001 is not reading out, the CHI and 2 and the X-ramp outp

21、uts return toOV.Ov on the V-channel outputcorrespondsto mid-screen on the OS4000 display and thus the chart recorder pen should be set to mid-scale unless specifically required otherwise. The X-ramp moves positive fromOVand thus the pen should be positionedto allow at least 1V positive travel. 2)Con

22、nect, if required for remote start/penlift. NOTE:The relay contacts are unprotectedand inductive loads should be suppressed to stay within the contact rating. 3)The delay time (from closing of relay contacts to start of read-out) is set by a front panel screwdriver preset.The minimum delay time of20

23、rns is sufficiently short for recorders for which no delay is required.The preset control range allows the delay time to be set to a maximum of 1 second but this can be increased to approx.10 sec. by increasing the internal capacitor C80I to I5tlF. 4)Obtain the required trace on the OS4000 and STORE

24、 or LOCK it. If the 50% hold facility is being used, the trace stored by the 50% hold will appear at the CH2 output,the other trace appearing at CHI. 5)Set the required read-out rate on the timebase range switch. 6)Press the start switch to initiate the read-out cycle. Note the display is inhibited

25、during read-out.At slow read-out rates, this will result in a blank screen for considerable periods.Similarly the OS4000 is prevented from accepting new data into the store during this period. 7)At the end of the read-out cycle, reset the timebase range switch as required to record subsequentdata. 3

26、.4THE READ-OUTCYCLE Fig. 1 shows a typical read-out cycle. The cycle is initiated by a negative edge on the start input produced by the push button or by remote start (see section 3.5). The relay contacts close within 0.5msec. of the start command and the preset delay period is started.At the end of

27、 this delay, the read-out is primed to start at T1 the end of the current display sweep on the 0S4000. Periodt3 has any value from 0 to I.2msec. depending on when the button was pushed but is unlikely to be a significant delay at chart recorder speeds.If required, the read-out marker, available at t

28、he back panel socket SK A.C. pin 2, can be connectedto the chart recorder event marker to indicate the exact start of read-out.At the end of read-out, the relay contacts open again within 0.5ms and all analogue outputsreturn toOV. 3.5REMOTESTART The remote start input appears on contact 3 on the bac

29、k panel socket SK AC. Read-outs may be initiated by a T.T.L.lowon this contact or by connecting it to contact 4 which is logic earth.This action has the identical effect to pushing the front panel button. CLOCKS 1 AND2 0 SINGLE CHlAND 1 TRACE CH2DATA 0 CHlANDCH2 ANALOGUE Dv OUTPUTS Operation DELAY O

30、IP CH ANALOGUE OUTPUT CH2 ANALOGUE OUTPUT X-RAMP ANALOGUE OUTPUT Section 3 START COMMAND ,:-j-: 1_11-.j , -I1-1-1- II 10.5msecI -Ft2iI II II , -_I9-0 j CHl OUT 1 CH2 OUT BUFFERS 0 separate the two channels and present them simultan- eously, the incoming data is held in two sets oflatches, one clocke

31、d on even addresses, the other on odd.The latched informationis then passed on to the digital to analogue converters (D to A) and also to the buffers, which protect the internal data from external effects such as short circuits or line reflections.At the end of read-out, the latches are cleared to b

32、inary 1000,0000 which producesav(mid range) at the analogue outputs. (b)X Ramp The X-ramp is produced digitally by a 10 bit counter clocked at each change of data input.The counter is cleared to all zeros at the end of read-out.The output of this counter feeds a third D to A and is buffered as is th

33、e Y data for the digital output. Circuit Description (c)Timing The start of read-out is initiated by triggering the delay. This immediatelyenergises the relay.At the end of the delay period, the start latch is set, holding the relay and putting a 1 on the D of the enable latch.The next sweep reset f

34、rom the OS4000 clocks this l to the out- put and enables the read-out. The start latch is cleared after two clock pulses putting a 0 on the D of the enable latch.The relay is now held on by theQof the enable latch.When the next sweep reset pulse arrives at the end of the slow scan, this 0 is clocked

35、 to the outputand the read-out enable goes low clearing the Y channel latches and resetting the X-ramp, thus terminatingread-out. The NORM input inhibits read-out when the OS4000 is in the normal mode, by puttinga 0 on the D input of the start latch and on the clear input of the enable latch. 4.2D/A

36、 CONVERTERS The D/A converters,IC821, 822, 823, are similar to those used in the OS4000.The outputcurrent produced at Pin 4 is converted into an output voltage by the following operationalamplifiers, IC 824, 825, 826.The current injected into Pin 14 of the D to A defines the output scaling, and the

37、external current injected into Pin 4 of the D to A, sets the zero.Each has a preset control to com- pensate for componenttolerances.Both pins are virtual earth points and so the currents can be completely defined by a reference voltage and a series resistor.The reference voltage is provided by regul

38、ator, IC827.The resistor and capacitor on the outputremove any high frequencypick up. Each channel has a half scale offset current introducedby R848, 849 and R841, 842 such that mid-screen on the display produces OVout. The X-ramp operates on 10 bits.The least significant eight are convertedto an an

39、alogue current by IC821. The two most significant bits are generated separately for current summationat the input of IC824. These additionalbinary weighted currents are provided by R822, R823 and R824 representing bit Dl, and R832, R833 and R834 representing bit D2. Transistors, TR802 and TR803, whe

40、n switched on, reverse bias diodes, D807 and D805/D806respectively, diverting the current from the summing junction.D804 is included in series with R854 to ensure thermal tracking between the current from IC821 and the two additional currents.IC821 draws a current toward -6Vfrom the summing junction

41、,proportionalto the digital input. Correspondinglythe two additional currents are normally on when their digital inputs are zero and their total current is balanced by that through R825 and R827. R824 and R834 adjust the currents representing D2 and Dl respectively.R829 adjusts the overall scaling w

42、ithout changing the matching between the three currents. 4,3LATCHESANDLATCHCONTROL Refer to the circuit diagram, Fig.8. The incoming data stream enters two 4-bit latches in each Channel, IC819, 815 and IC814, 818.TheQoutputs are used for all but the most significant bit, which arrives inverted by IC

43、804 (d) and is taken out from theQoutput. This ensures that at the end of read-out when the clear is taken low and all the latches cleared, the digital infor- mation presented to the D/A is binary 1000,0000 which is half full scale (OV at the analogue output). IC807 gates the clock pulses such that:

44、- (a)In dual trace or Lock alternate samples mode, informationfrom odd and even locations is clocked into CHI and CH2 latches respectively. (b)Informationfrom all store locations is clocked into both channels when in single trace operation. The operationis as follows:- The signal arriving at Pins 13

45、 and 2 of IC807 is the clock to be gated.The signal arriving at Pins 5 and 9 is the read- out enable.When low it inhibits clocks to both latches and clears them.When high, it enables clocks. The input dual trace is inverted by IC802 (b). In single trace operationit puts a 0 on IC805 Pins 13 and 9 wh

46、ich in turn puts a 1 on IC807 Pins 12 and 1. This allows clocks to reach both Y Channel latches simultaneously, fulfilling condition(b) above. In dual trace operationor lock alt. samples, IC802 Pin 4 is high, enabling the read address LSB to arrive at IC807 Pin 1 and its inverse at Pin 12. Thus when

47、 the LSB is High, the CHI latches receive clocks, when it is low CH2 receive clocks.This fulfils conditions(a). 4.4XRAMP COUNTER IC817 and IC820 are each four bit synchronousbinary counters and with IC816 are cascaded to form a 10 bit divider.They are cleared to zero at the end of each sweep and ste

48、pped with each change of Y Channel data, Le. following the read address through the read-out cycle. 4.5DATA SELECTOR Switches shown with 0 on select. The data selector, IC808 functions as 4 changeover switches as shown in FigA. The OS4000 normally reads out from the stores at a fixed Circuit Descrip

49、tion rate.Switch (a) changes this rate to one set by the Time- base switch, i.e. the write-rate pulses. The flip-flop, IC805 (a) and (b), retimes the write-rate pulses from P2 to PI to drive the read address counter.(See Fig.5.) In dual trace operation,the OS4000 normally reads even store locations only on one sweep and odd only on the next.(See section 4.5.4 of 0S4000handbook.) In the read-out mode, switch (c) ensures that the LSB address is taken from Cl rather than Cl, retaining read- out from all the store location.Switch (b) sends