What cause amplitude changed after 'multiply'?

1. What happens when you multiply two signals?
2. How do you reduce the amplitude of a signal?
3. Is modulation addition or multiplication?

What happens when you multiply two signals?

Multiplication of signals is exploited in the field of analog communication when performing amplitude modulation (AM). In AM, the message signal is multiplied with the carrier signal so as to obtain a modulated signal.

How do you reduce the amplitude of a signal?

The amplitude of a sound is controlled by multiplying the sound wave by a certain factor. A multiplier of 1 represents "unity gain", meaning no change. Multiplying by a factor between 0 and 1 reduces the amplitude of the sound.

Is modulation addition or multiplication?

Modulation is the process of merging two signals to form a third signal with desirable characteristics of both. This always involves nonlinear processes such as multiplication; you can't just add the two signals together.