Re: PLL to generate low frequencies

On Jun 3, 6:34 am, "paryanz" <dr.asth...@xxxxxxxxx> wrote:
Hi,

This is my first post to this forum. I have a reference oscillator of 12.7
MhZ, how do I generate the following frequencies using this oscillator

  16.863406408094434  Hz
  16.722408026755854
  16.694490818030051
  13.755158184319120
  12.562814070351759
  12.531328320802006
  12.062726176115802
  11.148272017837234
  10.405827263267431
  10.060362173038229
  10.040160642570282
  10.010010010010012

I would need roughly a 0.01Hz frequency resolution. Would a fractional PLL
be a solution to this problem.

Most of the papers I have read deal with increasing the output freq to
several Mhz or Ghz for implementing a PLL. But this implementation of mine
requires to reduce the generated freqs, I would appreciate any help advice
 or some kind of code which would help me solve this problem.

Thanks
Aryan

A PLL is not required for this problem. Have you read about direct
digital synthesis (DDS) or the numerically controlled oscillator
(NCO)? A DDS with a 32-bit phase accumulator should be capable of
0.003 Hz resolution at 12.7 MHz; to realize the frequencies you gave,
a 64-bit phase accumulator may be needed (7e-13 Hz resolution).

John
.

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