Then again, direct sampling SDR don't have an LO to leak, but do have a stable clock. There are some power supplies and digital systems with spread spectrum clocks. No reason one could not use a spread spectrum ADC clock, heavily over sampled of course, then average the samples where needed. There are some ADC they randomize the data bus for EMC.
Do they still have vans in the UK that driving around looking for un-taxed TV?
Do they still have vans in the UK that driving around looking for un-taxed TV?