At 05:14 PM 6/9/97 -0700, you wrote:
>Yes, RF amplifiers can and do modify the audio responce of a signal, both
>"good and bad". A few of the AM broadcast transmitters I've dealth
>with have sections in their manuals regarding amplifier operation for
>certain "types of fidelity". This also includes interfacing to various
>antennas which also modify the audio.
Modification of audio response by AM transmitters has absolutely no bearing
to amateur radio. In the case of AM radio, the desired audio bandwidth is
+/- 10 KHz at (approximately) 1 MHz. In an AM broadcast station one must
have a *SYSTEM* bandwidth (amplifier and antenna) of 2 % ... the equivalent
of an antenna and amplifier that would allow one to QSY from one end of 20
Meters to the other without any change in power output or antenna SWR!
In AM one needs to stragger tune the entire SYSTEM in order to get the
required bandwidth. The music vs. talk tuning is an acknowlegement that
one need not be quite as "broadbanded" for a talk radio format.
A properly designed amateur amplifier will have an output bandwidth of
at least 10 times the 3 KHz bandwidth of the normall SSB signal. Unless
the amplifier deisgn is such that it generates in-band distortion products
(IMD, clipping, etc.), it should have *NO* effect on transmitted audio
quality. If it effects transmitted audtio quality, it will only degrade
... Joe Subich, W8IK ex-AD8I
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