[AMRadio] Frequency Response


Edward B Richards zuu6k at juno.com
Sat Sep 25 13:54:00 EDT 2004


Hi Jim;

For the 55 years I have been in electronics, bandwidth has always been
defined as the half voltage points (-6dB). We all know that band passes
don't have vertical sides. Therefore it will be narrower above the -6 dB
points and wider below. Thanks for your input. 

73, Ed Richards K6UUZ


On Sat, 25 Sep 2004 10:29:14 -0700 (PDT) Jim Candela
<jcandela at prodigy.net> writes:
> Ed,
>  
>     You make a good point. I do however need to bring up that 
> bandwidth needs to be specified with a certain roll off in DB. For 
> example a mechanical filter in a receiver is often specified at -6, 
> and -60 db and with a certain shape factor.
>     A clean AM ham rig may be 30 Khz wide at the - 60 db points +/- 
> 15 Khz away from the carrier. That same rig may be 6 Khz wide at the 
> -6 db points, and 8 Khz wide at the -20 db points. So what bandwidth 
> is this rig? 





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