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        PRELIMINARY

 

Document type: 

Title: 

Revision date: 

Revision: 

User's Manual (MUT) 

Mod. V1729 4 Channel 12 Bit Sampling ADC 

22/06/2005 

3 

 
 
 

NPO: 

Filename: 

Number of pages: 

Page: 

00109/04:V1729.MUTx/03 V1729_REV3.DOC 

38 

9 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Fig. 2.3: simplified description of the trigger selection chain 

2.2  Validation of the trigger by a second subsequent signal. 

In the case where one would like to validate the data stored in the MATACQ chips before 
their transfer towards the RAM, it is possible to make use of the 

EXT_EN_TRIG 

input to 

introduce therethrough a validation signal (see figure 3c). This is particularly useful if the 
system produces such a signal with a delay greater than the maximum sampling depth 
(2560/Fp i-e 1.25

μ

s at 2GS/s and 2.5

μ

s at 1GS/s) and smaller than the transfer time 

towards the RAM (650

μ

s). This can thus permit a big decrease of the potential dead-time 

linked to the readout. In this case, the usual use of the 

EXT_EN_TRIG 

signal (which 

permits inhibiting the trigger as described on figure 3b) is inhibited. 
In order to perform the validation, a programmable 8-bit latency counter ( called 
POST_STOP_LATENCY) with steps of 2.5

μ

s is started at the end of the POSTTRIG, 

and if the external validation signal hasn’t arrived before the end of that delay, the 
Matacq chips switch back into the analog input signal writing mode thus waiting for the 
next trigger. If on the other hand the validation signal did arrive, the waiting data is 
digitized then stored into the RAM. This mode is validated thanks to the bit 5 of the 
TRIGGER_TYPE register (see IV.4). Moreover, a second 8-bit register ( called 
POST_LATENCY_PRETRIG) with the same steps of 2.5

μ

s permits the programming of 

the time to wait before enabling the trigger again if the validation didn’t occur. The 
minimum time for refilling is of 1.25

μ

s at 2GS/s and of 2.5

μ

s at 1GS/s. The minimum 

value in that register is thus 1. 

 

 
 
 

TRIGA 

Ch0 

Ch1 

Ch2 

Ch3 

DAC threshold 

TRIG enable 

Select 

Select 

Select 

TRIG_OUT 

TRIG_AUTO 

EXT TRIG 

    EnCh0 

+ 

- 

       EnCh1 

+ 

- 

       EnCh2 

+ 

- 

       EnCh3 

+ 

- 

EXT EN TRIG 

In italics with arrows : front panel signals. 

Содержание V1729

Страница 1: ...Technical Information Manual MOD V1729 22 June 2005 Revision n 3 4 CHANNEL 12BIT SAMPLING ADC MANUAL REV 3 NPO 00109 04 V1729 MUTx 03...

Страница 2: ...he User accident or any abnormal conditions or operations CAEN declines all responsibility for damages or injuries caused by an improper use of the Modules due to negligence on behalf of the User It i...

Страница 3: ...NIZATION BETWEEN THE CHANNELS 16 3 1 1 Channels from the same board 16 3 1 2 Channels situated on different boards 16 3 2 SYNC_OUT AND BUSY SIGNALS 16 3 3 CALIBRATIONS 17 3 3 1 Calibration of the inte...

Страница 4: ...ASES 7 FIG 2 3 SIMPLIFIED DESCRIPTION OF THE TRIGGER SELECTION CHAIN 9 FIG 2 4 SIMPLIFIED DESCRIPTION OF THE TRIGGER VALIDATION SYSTEM 10 FIG 2 5 BLOCK DIAGRAM OF A STANDARD ACQUISITION 12 FIG 2 6 TWO...

Страница 5: ...al of a trigger signal initiates the stopping phase of the sampling 2 1 1 At the end of this phase the state of the memory is set it then contains the last 2560 points sampled of which 2520 are valid...

Страница 6: ...not work properly with a pilot frequency Fp lower than 50MHz 1 3 Input signals Dynamic range The V1729 board integrates 4 analog channels The inputs of these channels are connected through double LEMO...

Страница 7: ...of the stopping of the acquisition The POSTTRIG programmable by the user permits defining and displacing the position of the trigger signal in the acquisition window It is adjustable in the 1 Fp to 6...

Страница 8: ...eral boards in order to produce at the exterior of the boards via their output TRIG_OUT a trigger which will be sent back to them in a synchronous way see figure 2 2 This mode is selected by the bit 4...

Страница 9: ...signal which permits inhibiting the trigger as described on figure 3b is inhibited In order to perform the validation a programmable 8 bit latency counter called POST_STOP_LATENCY with steps of 2 5 s...

Страница 10: ...his servo has to get locked again This implicates a typical waiting of 150 s before being able to reach the optimum of the sampling performances For this reason at each restarting of the acquisition t...

Страница 11: ...nowledge the request by writing a 0 in the INTERRUPT register but the latter is anyhow reset by the START_ACQ command The first solution has the big advantage of being less noisy for the front end of...

Страница 12: ...estal of a data cell is extremely reproducible 250 V RMS Due to the structure of the chip the dispersion of the pedestals presents a principal periodicity of 20 cells followed by a tiny individual dis...

Страница 13: ...eration necessary for the treatment of the data is therefore to unfold the circular memory in order to obtain a table of 2560 temporally ordered data see Fig 2 6 This can be done by example by realizi...

Страница 14: ...a jitter of a period of Fp The information of the 4 verniers from the same board being redundant in order to realize the temporal adjustement it is therefore possible to use solely the vernier from th...

Страница 15: ...o 0 due to signal propagation times in the board of which the calibration is described in 3 1 1 An alternative but equivalent solution consists in generating the reordered table through a rotation tow...

Страница 16: ...boards to generate the trigger signal on a fixed board master which triggers itself and to send its TRIG_OUT signal output to the external trigger input of the other boards via a NIM buffer if there...

Страница 17: ...value on the left side MINVER will be the zero of the vernier and the one on the right side MAXVER will correspond to a vernier of 1 Fp in other words 10 or 20ns The intermediate values will next be d...

Страница 18: ...n of the verniers The codes which implement the register setting is the following void TCAENADC Vernier char s 30 SetNCols 0 Setto PRETRIG SetPreTrig 1 Setto POSTTRIG SetPostTrig 1 SetTriggerType 0x08...

Страница 19: ...vernier channel 0 vernier It is then necessary to rearrange the buffer in order to obtain 4 arrays one per channel of 16384 samples each With such settings we send on each channel a slope signal with...

Страница 20: ...ither automatic or external The acquisition procedure is the same as for a standard acquisition but the reading of TRIG_REC can nevertheless be skipped Of course not the least temporal correction is m...

Страница 21: ...oard by software which corresponds to a sampling frequency Fe 20 Fp of 1 or 2 GHz 4 3 Input signals Dynamic range The V1729 board integrates 4 analog channels The inputs of these channels are connecte...

Страница 22: ...Filename Number of pages Page 00109 04 V1729 MUTx 03 V1729_REV3 DOC 38 22 4 4 Front panel Mod V1729 4 CH 12 BIT VCC EXT CLK ADC 8 TO 12 V 8 TO 12 V VME GPIB RESET CLOCK BUSY ACQRUNNING TRIG WR RAM IN...

Страница 23: ...uration elements on the V1729 The V1729 board is of VME 6U mechanical format The two connectors P1 and P2 of the VME crate are usable both for the supply and the VME dialogue However these boards can...

Страница 24: ...alf double LEMO I NIM EXT_TRIG External Trigger Half double LEMO I NIM EXT_DIFF_TRIG External Trigger Double pin I DIFF ECL EXT_CLK External clock LEMO I NIM TRIG_OUT Trigger Output LEMO O NIM BUSY SY...

Страница 25: ...is dominant in relation to the time spent awaiting the event Y depends on the bandwidth mode 4 5 5 Pinout of the non standard connectors GPIB Connector HE10 26 points male Reference J2 1 D1 2 D5 3 D2...

Страница 26: ...er up S12 and S13 address of the board J3 adaptation for the EXT_DIFF_TRIG input Place 100 ohms between the pins 1 and 2 and between the pins 3 and 4 J4 pull down for the GPIB Place an 8 resistor netw...

Страница 27: ...ust be identical The range is saturated with 2k that is therefore the minimum value The tabulation below displays the different resistor values necessary to obtain the targeted shifts It is also neces...

Страница 28: ...e same INTERRUPT register However it should be avoided because it is a source of noise during the data acquisition The reading of the data stored in the RAM is executed by realizing N successive readi...

Страница 29: ...TERRUPT register Broadcast Mode A writing at the address 30 decimal permits realization of a writing in all the V1729 boards present on the GPIB bus 4 7 Reading of the data in the RAM mapping During t...

Страница 30: ...ata The access to reading in the RAM is done by secondary addressing Its internal address is indeed controlled by a 16 bit counter RAM_INT_ADD located in the controller placed on the board in the FPGA...

Страница 31: ...O 1C YES YES W Com SOFTWARE TRIGGER NO 0A YES NO W R Reg TRIGGER THRESHOLD DAC LSB byte GPIB 8 0 0B YES NO W R Reg TRIGGER THRESHOLD DAC MSB half byte GPIB 4 0 0A NO YES W R Reg TRIGGER THRESHOLD DAC...

Страница 32: ...g is indirect the internal address of the RAM being defined by the RAM_INT_ADD counter located in the ALTERA RAM_INT_ADD this 16 bit counter fixes the internal address of the RAM for the bus access in...

Страница 33: ...his 8 bit register gives the distance between the column where one finds the column pointer at the arrival time of the synchronous trigger and the last column 128 It permits in practice to roughly dat...

Страница 34: ...xing of the Fp period It is initialized at 1 Bits Function 0 1 Val 1 Fsample 2GHz Val 2 Fsample 1GHz FPGA VERSION this 8 bit read only register permits reading of the version number of the FPGA The 3...

Страница 35: ...ower readout of the MATACQ chips The management of writing and of re reading the digital memory RAM The interfacing with the acquisition system The last four blocks except the RAM itself as well as th...

Страница 36: ...The elementary block of the analog acquisition is represented in Fig 4 4 It includes The 50 Ohm adaptation of the input A large bandwidth amplifier making it possible to feed the MATACQ chip in diffe...

Страница 37: ...channel 15ps RMS typical Time precision between two channels 20ps RMS typical Depth per channel 2560 points of which 2520 are usable Trigger Threshold setting dynamic range 0 5V Threshold setting ste...

Страница 38: ...6 2005 3 NPO Filename Number of pages Page 00109 04 V1729 MUTx 03 V1729_REV3 DOC 38 38 6 BIBLIOGRAPHY 1 E Delagnes D Breton Echantillonneur analogique rapide grande profondeur m moire French patent n...

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