Monday, November 23, 2009

3.5999MHz QRSS frequency

Having had my brains chewing on the problem for a while, the solution is really obvious, sort of.
Remember, the task is to generate a frequency of 3.5999MHz, using cheap and available components.

And here it is:
  1. generate 6.400MHz
  2. generate 8.000MHz
  3. mix! => 14.400MHz & 1.600MHz
  4. filter ...
  5. divide by four (FlipFlops) => 14.400MHz/4=3.600MHz
  6. filter ...
Regular CW could be done by enabling/disabling one of the flipflops.
FSK by pulling on one of the crystals.
In my design, I would probably pull one crystal for modulation and the other for the TX frequency.

Now, that was not that hard, or was it?