Signals: Time Domain We are concerned with electromagnetic signals used as a means to transmit data A signal is generated by the transmitter and transmitted over a medium The signal is a function of time but it can also be expressed as a function of frequency Time domain concepts: an electromagnetic signal can be either analog or gita Analog signal The signal intensity varies in a smooth fashion over time. Or, there is no breaks or discontinuities in the signal Digital signal The signal intensity maintains a constant level for some period of time and then changes to another constant level Time domain function of a signal: s(t/ pecifies the amplitude(in volts )of the signal at each instant in time 99 Signals: Time Domain • We are concerned with electromagnetic signals used as a means to transmit data. • A signal is generated by the transmitter and transmitted over a medium. • The signal is a function of time, but it can also be expressed as a function of frequency. • Time domain concepts: an electromagnetic signal can be either analog or digital — Analog signal • The signal intensity varies in a smooth fashion over time. Or, there is no breaks or discontinuities in the signal. — Digital signal • The signal intensity maintains a constant level for some period of time and then changes to another constant level. • Time domain function of a signal: s(t) — Specifies the amplitude (in volts) of the signal at each instant in time