Stephan Schaa wrote: > > > Thanks for your explanations, Bob! > > I understand the principles of driving the mixer with a squarewave > signal and that you use a comparator to change sine to squarewave. > > Where I'm failing at is the trick how to receive 30 mhz with a DDS > that make 37 MHz max without getting problems with nyquist. Can you > use a comparator to double your VCO frequency without getting > problems at the duty cycle? > > > Stephan > > > Stephan: He uses 2 DDS chips that are locked in quadrature. An I and a Q sample at 37 MHz is 2 samples at a 37 MHz rate, or 74 Meg samples per second. This satisfies the Nyquest \.
Dave - WB6DHW <http://wb6dhw.com>
