[time-nuts] 5 MHZ PIC PPS Divider?

Bruce Griffiths bruce.griffiths at xtra.co.nz
Wed Apr 16 00:31:06 EDT 2008


For one version of a classical time to amplitude converter (TAC) with an 
ADC connected across the ramp capacitor see:

- Datasheet for LTC1276 towards the end.

With an increased power supply for the current sources a somewhat more 
linear version that doesnt require the non linearity correction is possible.
Alternatively you can do the linearity correction in software.

When sampling using a sinewave style interpolator one takes sine and 
cosine samples hence the phase angle is can be calculated from the samples.
If the same sinewave clocks the counters then one can interpolate the count.
A dual simultaneous sampling ADC is needed for each input.
Expanding to multiple channels is easy particularly if they all sample 
the same continuously clocked counter.


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