[time-nuts] ACAM GP22 Chip

ed breya eb at telight.com
Wed Nov 25 17:19:02 EST 2015


I don't want to muddy the water too much, but I'd second going 
all-digital, along the lines of what Bob L. recommended earlier. It 
seems like you just need to make some specific delay times, so various 
logic counting or shifting circuits should be just fine - and 
well-defined and understood.

If you go with coaxial delays, the loss and dispersion may cause much 
analog grief to determine how much compensation and amplification is 
needed, and the thresholds for comparison for squaring it up. This is 
especially aggravated with long lines.

In the hundreds of meters range, it may be better to go with optical 
fiber instead. The bandwidth can be huge, and losses will be tiny, even 
into km lengths, and all kinds of E/O and O/E conversion parts are 
available for the ends. There can be some timing jitter due to the noise 
of the conversions, and AGC issues, but probably less than the noise 
associated with adapting long coax cables to this task.

Another option may be acoustic glass delay lines. I don't know if any 
are made nowadays, but they were common in TVs and VCRs, with time delay 
somewhere in the horizontal line duration range, and very compact. It 
could be that there are many more kinds for various applications (or 
maybe all obsolete - replaced by digital).

Ed


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