Question
I get an unwanted 1 kHz tone in the demodulated AF spectrum after starting the generator in the Expert Mode using dialing.
Where does this tome come from?
CMA180 Expert Mode - unwanted tone in demodulated audio
Answer
After presetting the Expert mode the CMA180 will reload the following RF generator settings:
If now for example FM would be choosen in combination with free dialing, the generator mode has to be set to to "Free Dialing" in addition.
In standard it is set to "Single Tone"
This means, that this 1 kHz single tone will be sent out between the dialing phases.
If the timing of the dialing phases is changed to a higher level, one can see, that the 1 kHz tone disappears while the dial tones are sent out.
After changing the AF mode to "Free Dialing", the 1 kHz tone no longer will be sent:
