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#1
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Are you crazy... that unit can be made to have tremendous modulation.
Professor www.telstar-electronics.com |
#2
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Are you crazy... that unit can be made to have tremendous modulation
Was that directed at me or Scotty?..They way Google displays the posts it came out under mine so I`m not sure....I actually said that it sounds like crap and has no modulation BEFORE you do anything to it..I`m very aware it can be made quite loud and proud with the right tricks ![]() |
#3
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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 Professor wrote: Are you crazy... that unit can be made to have tremendous modulation. Professor www.telstar-electronics.com |
#4
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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 |
#5
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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 |
#6
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******
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 Jay, I respectfully disagree. An AM carrier doesn't change, just sidebands are added in the mixing (modulation) process, and the instantaneous voltage shown on an o-scope will be 4 times greater then the carrier power itself. Since the audio added is 50% of the carrier, the RMS power will be 150% of the unmodulated carrier. The peak to peak voltage is greater. Put a 1000 Hz tone on a signal and look at it on spec-an. (make sure to do this test with an unmodified radio, "swing kits" ruin proper AM) |
#7
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On Tue, 21 Feb 2006 12:29:25 -0500, Scott in Baltimore
wrote in : ****** 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 Jay, I respectfully disagree. An AM carrier doesn't change, just sidebands are added in the mixing (modulation) process, and the instantaneous voltage shown on an o-scope will be 4 times greater then the carrier power itself. Since the audio added is 50% of the carrier, the RMS power will be 150% of the unmodulated carrier. The peak to peak voltage is greater. Put a 1000 Hz tone on a signal and look at it on spec-an. (make sure to do this test with an unmodified radio, "swing kits" ruin proper AM) It's about time to put this argument to rest...... you're both right. The amplitude of the -signal- changes according to the modulation, but the -carrier- is steady. The difference is that the signal (as seen on an o-scope) is the vector sum of the carrier and the sidebands, while the -carrier- (as seen on the spectrum analyzer) is only an isolated component of the total signal. Does that clear things up a bit? ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#8
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Hello Scott:
I think we are getting the Time Domain mixed up with the Frequency Domain. My comment was on a Oscilloscope voltage measurements which are in the time domain. Without the RF Carrier voltage being modulated, increasing and decreasing you would not have modulation of course. I never said the power in the carrier changes. Or maybe I said it poorly?!??!?!? But by added in more modulation power, like I said will allow for the finial rf amplifier to have more modulation power, allowing for more RF Carrier to be fully modulated, if it can handle the extra power. Simple stuff. More power and modulation kicking a high drive amp will cook! I have seen where the radios have been somehow modified to allow unlinear modulation, that is the upper and lower envelopes are not identical, and the radios still sounds ok. Yeah I don't know what they do for the swing mods?!??!!?! I put in Amplitude Modulation Envelope into Goggle and got a bunch of neat web sites on the subject. Jay in the Great Mojave Desert, ....just down the road ah ways from the fillin station. Scott in Baltimore wrote: ****** 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 Jay, I respectfully disagree. An AM carrier doesn't change, just sidebands are added in the mixing (modulation) process, and the instantaneous voltage shown on an o-scope will be 4 times greater then the carrier power itself. Since the audio added is 50% of the carrier, the RMS power will be 150% of the unmodulated carrier. The peak to peak voltage is greater. Put a 1000 Hz tone on a signal and look at it on spec-an. (make sure to do this test with an unmodified radio, "swing kits" ruin proper AM) |
#9
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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. 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. james |
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