06-05-2017, 06:15 PM
(06-05-2017, 05:44 PM)Nowhere-Man Wrote: I read some stuff on the BFO that frankly confused me. As I understand it at this point the BFO oscillator will be set 1000 cycles above the IF. The carrier is CW for the morse so just a continuous unmodulated wave with breaks (as dots and dashes).
The point being that, when mix two frequencies together you end up with four - the two you started off with and the sum and difference products. In the example you cited, the difference frequency is 1000Hz which is what makes the CW audible - otherwise you would just hear a kind thumping as the carrier turns on and off, assuming that the signal level is high enough.
It is the same principle as a mixer/oscillator where the difference frequency is 470kHz, 1700kHz or whatever other IF frequency you require.
