Signals and Systems

Appendix

RANDOM SIGNALS

The signals like noise voltage in a resistor due to thermal voltage, temperature in a city every morning or during the whole day, load on a power station etc. cannot be expressed any suitable mathematical expression. Therefore it is impossible to represent them by any definite graph. These signals are termed as non-deterministic or random signals shown in Fig. A1.

 

 

Fig. A1 Random signal

 

Figure A2 shows the readings obtained by a digital multimeter for a random signal which may not be able to assume all the values but only the certain values in which case it is a continuous time discrete random signal. If we take samples ...