1. Basic operations performed over the dependent variables
2. Basic operations performed over the independent variables

In Part I, we discussed addition and subtraction operations which belong to the first category.

Now, in this article, we continue our analysis so as to know more regarding three more signal operations which belong to the same group (i.e., the basic operations which are performed over the dependent variables representing the signals).

### 3. Multiplication

The next basic signal operation performed over the dependent variable is multiplication. In this case, as you might have already guessed, two or more signals will be multiplied so as to obtain the new signal.

Mathematically, this can be given as:y(t) = x1(t) × x2(t)                     … for continuous-time signals x1(t) and x2(t)andy[n] = x1[n] × x2[n]                  … for discrete-time signals x1[n] and x2[n] the resultant discrete-time signal y[n] obtained by multiplying the two discrete-time signals x1[n] and x2[n] shown in Figures 1(a) and 1(b), respectively.

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