Loris,
I do not claim to be an expert on mixers.? I am only an amateur at understanding how they work.? Here is what I think would happen.
The DC voltage would be a 0Hz signal that is being added to the BFO frequency which would put the BFO signal on the input to the SSB filter.? So yes to your question.? Biasing the product detector would pass the BFO signal to the SSB filter.? In the ?BITX v6 That would send an 11.056Hz signal to a filter that is designed to pass signals from 11.057MHz to 11.059MHz so there would be a much-reduced signal being sent to the following stages for frequency mixing and amplification.? In a properly adjusted rig that could be as much as 30db to 40db down.
Note that the above BFO and Filter frequencies are approximate for description only.? They would vary depending on the specifics set for the rig under test and the actual SSB filter characteristics.
If the intent is to use it for CW like is done in the first mixer of the ?BITX, then as is done there you would need to adjust the BFO frequency on key down so that it will generate the correct signal to get through the SSB filter, then further adjust one of the later mixers to be on the correct frequency to transmit.
Again, these are my thoughts.? I am open to any comments or corrections.
73
Evan
AC9TU
