[Elecraft] New K3 SN#207 built but question on AM Filter

[David Woolley]

David Woolley (Elecraft) wrote:

Oops. I calculated this with one sideband equal in amplitude to the 
carrier, well that may well be true if you are trying squeeze the last 
Hz out of the receiver filter, the corrected  values are:

> If  you do that with standard AM (envelope) detection, you will get up 
> to about 20% (even) harmonic distortion.  You will probably get better 

22% (need to double check this, but no time now.)

> audio treating it as SSB, in spite of frequency and phase errors.
> 
  (For Scroggie fans, consider the phasor diagram for 100% modulation at
> the point where the sideband is at 90 degrees to the carrier.  That 
> gives an amplitude of sqrt(2) when you should just have the nominal 

sqrt (1.5)

> carrier amplitude of 1.  At 0 and 180 degrees, you get the expected 

Half the nominal carrier amplitude.

> amplitudes of 1.5 and 0.5)
> 
> 


-- 
David Woolley
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