[BC] agile AM Tx with LP filter

[John Lyles]

Instead of a microprocessor controlled filter tied to the rigs frequency selector, a push pull amplifier (assume good cancellation of second harmonic) might have low enough second harmonic that only a single low pass filter for the higher order harmonics would be adequate.  However, for a station at the low end (540 KHz) the third harmonic would still be in band, so it would have to have at least some switched components in the filter. Also, I don't know what sort of second harmonic attenuation one gets with a push-pull class E rig like a BE - before the filter. 

John

> Message: 24
> Date: Tue, 24 Apr 2007 12:54:32 -0400
> From: "Jim Tonne" <tonne at comcast.net>
> Subject: Re: [BC] Freq agile AM transmitters
> To: "Broadcasters' Mailing List" <broadcast at radiolists.net>
> Message-ID: <000701c78691$3c6a0730$2602a8c0 at jim177093b3dd9>
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> 
> 
> Willie:
> 
> Yes, just like the ham rigs, it looks like about 6 (maybe 7)
> band would be needed.  Each band would be about 20%
> in width.
> 
> So the transmitter would have to have 6 or 7 output
> filters to get harmonics under control.
> 
> Nevertheless, this is quite a complication when compared
> to a simple rig with no output tuning at all.
> 
> - JimT