On 6/30/07 8:01 PM, in article
1183258907.121760.316050@g37g2000prf.googlegroups. com, "Radium"
<glucegen1@gmail.com> wrote:

> On Jun 30, 7:43 pm, Jeff Liebermann <j...@cruzio.com> wrote:
>
>> The carrier does NOT vary in amplitude. If
>> it did, that would be modulating the carrier, which is the job of the
>> modulator, not whatever is producing the carrier.
>
> Exactly. The modulator signal modulates the carrier wave. If there is
> no modulator signal, then the carrier does not vary by amplitude or by
> anything.
>
> One poster stated that the signal with the higher-frequency is
> automatically the carrier wave while the signal with the lower-
> frequency is automatically the modulator wave. This is not true. What
> I was trying to say is that an AM radio carrier wave cannot vary
> significantly by anything other than its amplitude [though, as one
> poster pointed out, the AM carrier can experience extremely-negligible
> variations in frequency]. If an AM radio signal has that restriction,
> it is the carrier wave. If an AM radio signal does not have that
> restriction, then it is the modulator wave. This is true, even if the
> AM carrier wave is of a lower-frequency than the modulator wave.
> That's what I was trying to say.
>
> In AM radio, determining which is the carrier wave and which is the
> modulator wave is not by which has the higher frequency but rather by
> which has the restriction that I stated.
>
> If there is no modulator signal, then no carrier signal of any type
> [AM, FM, etc.] will vary by any quality [frequency, amplitude, phase,
> etc.]
>

You should just recall that post.