Lecture 17 Information Signals ECE 205 Prof Ali

Lecture 17 Information Signals ECE 205 Prof. Ali Keyhani

Signum Function A function which is a combination of two step functions:

Exponential Rise Composite waveform generated by subtracting an exponential from a step function: - Signal is referred to as charging exponential - Characterizes the voltage build up in resistor-capacitor circuits

Damped Sine Multiplying sin signal by an exponential:

Waveform Partial Descriptions • Instantaneous value: The value of a waveform v(t) and i(t) at time t is called the instantaneous value • Partial descriptions: Parameters that characterize important features of a signal but do not give a complete description

Amplitude Descriptions • Peak Value: maximum of the absolute value of the waveform • Peak-to-peak Value: total excursion of v(t)

Amplitude Descriptions • Average value : average value or dc component is the area under the waveform over some period of time T divided by the time period: • The net area is the area above the time axis minus the area bellow the time axis • ac components such as sine wave have zero average value

Amplitude Descriptions • Root-mean-square value or Vrms is a measure of the average power carried by the signal • The instantaneous power delivered to a resistor R: • Average power:

Example 1 Find the average value of the waveforms