Need advice!

[ken white]

The one and only thing I know for sure in that entire post, and have know for 15 years is that modulation is the percentage of information reproduced expressed in degrees of the sign wave. I understand you have taught yourself mostly on the net, do me a favor and google modulation. The class of amp indicates the percentage of modulation. Class a = 360 degrees. Class AB>180 but <360. Class b= 180. Class C<180. Class D=0.

If what lords is saying by saying "over 100% modulation" is that the modulated input drives output power to a level that is greater than double the carrier power level then the term modulation shouldn't be there. I guess it is better to say that the jargon is different.

The modulation of a transmitter will be the exact same, expressed in degrees or as a percentage, weather you are outputing just above dead key, or if your swinging up as hot as the amp circuit will be stable. Distortion comes when the increased power gets to a point where the amplifier circuit is overdriven and the modulated signal breaks down (bad,bad,bad if you are underwater and using a microphone for your eyes!) or if, because of the design of the circuit overmodulation occurs. ( usually only in class a, or in a class A/B of high percentege.) I have literally put my life on this electical fact for 6 of the last 10 years. If the jargon is different, GREAT!! Then I think I understand where all my confusion comes from. But if you look at any text book ( I personaly like the Navy NEETS mods,) it will explain to you the exact thing I just did.

Thanks again for all your help
Ron

You need to re-read your NEETs modules as I don't believe they describe what you are describing.

Modulation in simple terms is intelligence applied to a carrier and has absolutly nothing to do with Amplifier bias. In an AM or SSB signal, there are no degrees associated with the modulated signal and the carrier. If you are talking about FM or Phase shifted signals, then modulation is associated with an angle, or time shift.

Distortion comes from any non-linear amplification, so any class of amplifier other than Class "A" will distort the signal even if the modulation is not greater than 100%.

Ken White, ETCM, USCG retired...

 

[mopar2ya]

mopar, just so you dont feel alone in this one; i thought the same thing that you did about what noyb wrote.
i thought, "how rude. mopar is a very helpful guy."

glad to know it was just a misunderstanding, as these things can easily escalate for no reason.

Thanks loosecannon. I am glad it was a misunderstanding as well. Good call on the Lou Franklin material. I love that book. With his electronics background, noyb72 will understand it much more completely than I do.

Mopar