Digital Delay Generator / Pulse Generator

PCI-Card: BME_G02p
 
 

BMEG02p.gif
 
 


for precision Timing with low Jitter

Circuit Description

The BME_G02 is a PCI delay generator with 3 outputs generating signals delayed from 50nsec to 429sec, in steps of 25 picoseconds, with respect to a trigger event. The trigger event can be generated by an internal counter or by an external signal fed to the trigger input connector.
The BME_G02 can acheive repetition rates between 0.002Hz and 8MHz.

A trigger circuit starts the delay counters. There are 4 counters, T, A, B and an auxiliary counter. The T, A and B counters actually produce an output signal, while the auxiliary counter can only be used to produce an interrupt.
Three different output modes can be selected:
- Pulse-Mode: a delayed pulse of specified pulse-length
- Edge-Mode: each elapsed delay causes level transition of the output signal. After the last delay expires, all outputs are reset together.
- Gate-Mode: the outputs A and B can be combined to form a gate signal, i.e. a rising(falling) edge after delay A has elapsed and a falling(rising) edge after delay B has elapsed, so you get an pulse with a variable(25ps resolution) pulse-width from 2ns to 429s.

The BME_SG02 card synchronizes the delayed ouputs to an external trigger with an RMS Jitter of less than 250ps.
An external clock can be fed to the external trigger input connector, which can additionally be gated and prescaled.
If more than 3 outputs (or more than 1 gate output) are needed, two ore more cards can be slaved with a ribbon-cable, resulting in 6 or more synchronous delayed outputs.


Specifications

Delays Delayrange 50ns - 429s (44bit)
  Delayresolution 25ps
  min. Dalaytime : 50ns (Insertion-Delay)
  Error :    <(1ns + 25ppm * delay)    )1
  RMS Jitter:      Output to Output: <(50ps + 10-8 * delay)       )1
Trigger to Output: <(250ps + 10-8 * delay)     ) only BME_SG02
Trigger to Output: <(50ns + 10-8 * delay)     ) BME_G03, BME_G05
Trigger External: Threshold Range: -2.5V to 2.5V in Steps of 1.2mV
    Slope :                rising or falling edge
    Input impedance : 10kW or 50W
  Internal: by a modulo-N counter running with the main clock
    Repetition Rate :     0.002Hz - 8MHz
Outputs T,A,B Mode : Edge, Pulse or Gate (AB) output
  Load :  50W or 25W,
    T0 output can be configured for NIM output pulse
  Risetime :  <2.3ns for TTL 
<1.4ns for ECL or NIM (typical)
  Levels :  TTL: 0 to 4V normal or inverted      (optional 5V amplitude)
    ECL: into -2.0 normal or inverted
    NIM
General Clock Source:  Internal:    10Mhz (80MHz)
             accuracy: 25ppm        T.C.: <1ppm/C        )1
    External:    max. 250MHz with prescaler
  Interface :  PCI-Bus;        signal compatibility 3.3V and 5V
  Interrupts : can be fired with the finish of any of the delays T, A, B or after the auxiliary delay has elapsed.
    It is also possible to fire an interrupt with the main trigger of the delay generator(s), or after a fixed number of triggers has occurred.

 )1 Accuracy and Jitter depend on Clock Source (specs with 25ppm clock source)
     optional 1ppm clock source available


Options


  

  • BME_SG02p:  Outputs synchronized to external trigger. 

  • BME_G03p:  Delays individually resettable with a resolution of 100nsec. 

  • BME_G04p:  Delays can be individually fired a second time after main trigger. 

  • BME_G05p:  the ouputs can be vetoed with a modulo-counter 

Software


  

Application:    Laser Timing

Download pdf:      bme_g02p.pdf(143kB)


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