Something like this? (see image)
On Wed, Dec 25, 2019 at 1:02 AM Magnus Danielson <[email protected]> wrote: > > Hi, > > I realize that I lack a microstepper. Consider that I have a stable and > low-noise 5 or 10 MHz but I want to resynthesize to correct frequency > and do phase-steps, and doing so without too much loss of noise. > > This has traditionally been done using a variation of techniques, but if > we would use some of the things that happened lately, pretty OK > performance should be possible to achieve without too much hardware. > > OK, so after a discussion with Bob, here is one sketch for a > possibility, just to toss one proposal to crush into pieces and propose > improvements or better versions. > > So, consider using a modern Silabs chip clocked from an oscillator, > producing a offset generator with I/Q and then do an I/Q mixdown to a > beat frequency, which is digitized by a pair of ADCs. A pair of DACs > produces I/Q which is used to mixed to produce the output signal using > the signals from the Silab. The ADCs/DACs can be either be fed to some > CPU platform or FPGA. With this platform one can choose to servo the > reference oscillator, or just modify the beat received. Maybe use a > Raspberry Pi as platform. Rotating the vector and steering the rate of > rotation should not be extremely hard to do. The input vector can be > added internally or used to steer the oscillator. Either way, the in > loop noise from the Silabs will be fairly well suppressed since it only > acts as a transfer oscillator. > > So, suggestions, thoughts and improvements? > > God Jul and Merry Christmas! > > Cheers, > Magnus > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.
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