Hi Dan,

I have to ask.. if all four syncs are the same, why are there four of them? ;)

-Paul

On Thu, 4 Mar 2010, Dan Werthimer wrote:



hi randy,

the sync outputs from the adc yellow block are a copy of the signal that is injected into the adc's sync input SMA connector. (in your case, the 1 PPS signal). all four syncs are identical.

to know which adc sample is taken on the 1 second tick, one needs to calibrate by looking at a known source on the sky, or by coupling the 1 PPS signal into the analog input. this offset can change everytime the boards are powered up (there is a divide by four counter in the adc).

best wishes,

dan

On 3/4/2010 11:06 AM, Randy Mccullough wrote:
Given the following scenario...

A high speed sampler comprised of...

  1 iBOB with logic fabric running at 200MHz, derived from ADC0
  1 ADC2x1000-8 operating in its interleaved mode with an 800MHz
    sampling clock
  1 1PPS Site Timing Reference applied to the ADC's SYNC IN

Is it possible, using the four SYNC outputs of the ADC block, to
ascertain which of the 8 samples presented during a logic clock
cycle was most closely aligned with an in-coming 1PPS signal?

Randy

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