Thread: WWRB ?
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Old January 10th 05, 04:17 PM
Art Harris
 
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HankG wrote:

O.K., guys, I got it. Don't really need to know the station's

bandwidth.
It's just that I've never heard a station sound exactly like that.

How about my question modulation (limit ?),


You can't exceed 100% modulation on negative peaks because the
modulation envelope can't be less than zero. There are "super
modulation" techniques that allow a bit over 100% on positive peaks.

As for bandwidth, if there is no distortion, the bandwidth of an AM
station should be twice the highest audio frequency transmitted. For
high fidelity voice modulation, the sibilants (mostly "s" and "t"
sounds) may have frequency components up to nearly 10 kHz. Music can go
higher than that. So unless the higher audio frequencies are filtered,
the bandwidth of an AM station could be 20 or 30 kHz (not good with the
5 kHz channel spacing on shortwave). Just for reference, I believe the
allowable bandwidth for an AM broadcast station in the US is 10 kHz.
Art N2AH