TICC-TAC-TADD! Opinions wanted. (mainly TAPR stuff question)

[tkamiya]

I am making a TAPR TICC and TADD2-mini combination unit.

TADD2-mini allows output to be synchronized with external standard.  Say there is a 10MHz coming in.  TADD makes it into 1pps.  If there is another pps connected (say from GPS) it can synchronize with that.  As I  understand it, this happen once only.  Next count is on its own without syncing.

I could, for example, sync it with reference input, or sync it with second TADD2-mini.  Either way, two signal will start exactly in sync first then let it drift.

What I am not sure is, with TICC, is it even necessary? 
Does anyone think there will be a need for it?

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My current plan
2 TADD2-minis.  In and out connector on front panel.  1/2.5/5/10MHz selector on front panel.  1 pps LED on front panel. 

1 PICC.  In connector on front panel.  "now measuring A" and "now measuring B" LED on front panel.  Reference input, on front panel.  (no internal reference)  USB on front panel.  I am not quite sure why I need the LED...  doesn't "reading" happen simultaneously?  Are there a mode that I'm not aware of where counting happens only on one or alternately?

I don't plan to make this into a Swiss army knife.  Flexible to a degree but nothing more.

Opinions and Ideas, please.

[awallin]

I could, for example, sync it with reference input, or sync it with second TADD2-mini.  Either way, two signal will start exactly in sync first then let it drift.

re "exactly": I believe the sync input of a PICDIV/tadd2 synchronizes the output 1pps to within one cycle of the input-frequency, e.g. 100ns for 10 MHz.

What I am not sure is, with TICC, is it even necessary? 
Does anyone think there will be a need for it?

if the single-shot noise of the TICC is acceptable for you then it is a cheap time-interval counter for measuring how the two 1PPSs move relative to each other.
The TICC has on-board LEDs which show when ch1 and ch2 trigger IIRC. The TICC will need a 10MHz reference frequency that defines the timebase.
Something like a SR620 or Keygilent 53230A is lower noise but costs more.

If you want to DIY there are lots of variations of the picdiv out there. I've made a board like this: https://github.com/aewallin/PICDIV_Board_v3

AW

[tkamiya]

Thank you.

Now I have/had the unit, it appears syncing isn't necessary at all.  So I have it not set up that way.  Yes, there are two LEDs, one for each channel.  But what they do is, illuminate when each channel enters LOOP in the program.  Because it measures both channels almost simultaneously, they blink together for human eyes.  I thought it will detect arrival of input pulse, but it really doesn't look that way.

Thanks for your reply.

[texaspyro]

I thought it will detect arrival of input pulse, but it really doesn't look that way.

On mine, they seem to blink with the pulses.  I can see two distinct blinks when feeding it non-synchonized inputs.