[TenTec] Superhet Receiver Types?

[Ken Brown]

Hi Mario,

A BFO and a product detector perform frequency translation, IF to AF. So 
while "single conversion" receivers with only one LO and one IF and an 
AM detector are correctly called single conversion, as soon as you use a 
BFO for CW or SSB there are two heterodyne conversions going on, and it 
is really dual conversion, even if the common terminology fails to 
recognize that.

By the way, the first use of the term "heterodyne" was by Fessenden, who 
used two CW carriers beating against each other as a way to make AM 
detectors work with CW. Later they moved one of the oscillators to the 
receive end of the path, and it became a "local oscillator". This was 
before Armstrong's "superheterodyne".

73 DE N6KB

>N6KB> A "direct conversion" superhet just has one local oscillator and
>converts the incoming signal directly to audio.
>
>Conversion or mixing is frequency translation (DC = 0 IF) with local
>oscilator and should not be confused with signal detection (BFO for CW/SSB
>or DSP software).
>
>73 de Mario, S56A, N1YU
>
>
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