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On Fri, 24 Feb 2006 01:00:08 GMT, Lancer wrote:
+On Tue, 21 Feb 2006 21:04:25 GMT, james wrote: + +On Tue, 21 Feb 2006 04:24:38 -0800, Jay in the Mojave wrote: + ++james wrote: ++ ++ On Sun, 19 Feb 2006 15:40:53 -0800, Jay in the Mojave ++ wrote: ++ ++ +++Hello All: +++ +++I am hearing that many guys are addeding in another modulation IC, and +++Modulation transformer to double the audio power, allowing a higher +++carrier power to be 100% modulated. +++ +++Jay in the Mojave ++ ++ ++ ****** ++ The carrier in Double Sideband Full Carrier Amplitude Modulation ++ should remain constant during modulation. If not, then you have a far ++ greater problem. ++ ++ james ++ ++Hello James: ++ ++No thats not how AM works. The Modulation increases and decreses the ++amptitude during Modulation. Thats how double sidband full modulation ++works. Look in a old ARRL Book. ++ ++ ++Jay in the Mojave +***** + +I think you need to go back and reread and comprehend what those old +ARRL handbooks say. Then m aybe I suggest a good university textbook +on Communications. Oh by the way you may want to brush up on y our +Calculus and Differential Equations at the same time. + +Whats your damn problem james, does being a pompous ass come natural +to you? + ****** Really now. Maybe you should go back and comprehend what told me. I just responded in a manner that reflected my education and skills. If that is pompous to you then so be it. But mathematically to truely understand AM modulation does require a higher level of mathematics than just adding two plus two. ******** + +AM(t) = f(t)*cos(wc*t) + A*cos(wc*t) + +where AM(t) is your Amplitude modulated signal with respect to time. +f(t) is the function that mathematically describes the modulating +frequency. +wc is the carrier frequency +t is time +A is amplitude + +Taking the Fourier Transform of the carrier portion (A*cos(wc*t) +yields an impulse function with amplitude A at frequency wc. The rest +of the equation is your double sideband suppressed carrier and when +the Fourier transform of this is taken it will yield a frequency that +is the audio frequency plus and minus the carrier frequency at +amplitude of half the audio power. + +I hope that this helps in your understanding of what Double Sideband +Full Carrier Amplitude modulation, more commonly called AM, is. + +As long as you understand it, thats all that matters... + ***** Yes I very well do! **** + +james + +Does your formula show that SSB is AM also? ******* Yes, remove the A*cos(wc*t) term and you have Double Sideband suppressed carrier. Add a term for a bandpass filter and you will have single sideband suppressed carrier. Yes DSB and SSB are AM signals. james |
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