Difference between positive and negative modulation

[koushikr_in]

positive modulation advantage

can somebdy explain the difference between positive and negative modulation?

 

[sergio mariotti]

I don't know exactly, and i don't know if answer to your question, but I write about a function present in a syntetizer with modulazion option and a "switch" called +/-. It's an old Wiltron Synt.

If +, and modulation AM, as modulating level increase, also modulated level increase.
If -, and modulation AM, as modulating level increase, the modulated level decrease.

 

[Borber]

For positive modulation, when modulation signal goes positive the amplitude of AM signal increases or at FM instantenious frequency increases. At negative modulation the result is oposite.

 

[koushikr_in]

i suppose that positive modulation is used in AM.
but what abt the application of negative mod?

 

[echo47]

Television is broadcast with negative polarity. White is low amplitude, black is high amplitude. One advantage, the blacker-than-black sync tips become steady maximum-amplitude pulses, so it's easier to design a receiver AGC circuit. Another advantage, noise spikes appear black rather than annoying white.