Pete KE9OA wrote:

Quasi synchronous detection is a non-PLL type of sync detection.......like
the type that was used in the Drake R7 receiver. Basically, it consists of
using a mixer to demodulate the AM signal in this way: the I.F. signal is
split into two paths.
The unprocessed I.F. signal (one of the paths) is applied to the RF port of
a mixer, while the other path is squared up through a limiting amplifier and
applied to the LO port of this same mixer.
The demodulated audio is taken from the I.F. port (output port in this case)
of the mixer.
I did a similar design a couple of years ago, using a Philips SA637 Digital
FM Receiver chip. Philips discontinued that device so I went with the AD607
for my subsequent design.
I hope this helps.

Ahhhhh yes, in the Drake R7 it's known as "synchro-phase" detection.

dxAce
Michigan
USA