Cingular cell phone service - Re: AM electromagnetic waves: 20 KHz

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Re: AM electromagnetic waves: 20 KHz

Don Bowey

2007-07-06, 12:33 pm

On 7/6/07 9:36 AM, in article
isw-F124E8. 09362406072007@newsg
roups.comcast.net, "isw" <isw@witzend.com>
wrote:

> In article <C2B399E5. 6DB60%dbowey@comcast
.net>,
> Don Bowey <dbowey@comcast.net> wrote:
>
>
> And requires, for proper reception, that a carrier be recreated at the
> receiver which has not only the amplitude of the original,

There is no need at all to match the carrier amplitude of the original
signal. You can use an excessively high carrier injection amplitude with no
detrimental affect, but if the injected carrier is too little, the
demodulated signal will be over modulated and sound distorted.

> but also its exact phase.

Exact, not required. The closer the better, however.

> Absent some sort of "pilot" to get things synchronized,
> this makes reception very difficult.
>
> Isaac

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