Analog Waveforms

Analog Waveforms

Analog signals constantly vary in one or more values, and these changes in values can be used to represent data. Analog waveforms frequently take the form of sine waves. The two characteristics that define an analog waveform are as follows:

Frequency. Indicates the rate at which the waveform changes. Frequency is associated with the wavelength of the waveform, which is a measure of the distance between two similar peaks on adjacent waves. Frequency generally is measured in Hertz (Hz), which indicates the frequency in cycles per second. Frequency is illustrated in Figure 7.2.
Amplitude. Measures the strength of the waveform. Amplitude is illustrated in Figure 7.3.

Some analog devices can encode data using a property of waveforms called phase. Figure 7.4 illustrates waves that differ in phase. These waveforms have identical frequency and amplitude, but they do not begin their transitions at the same time.

Each of these characteristics—frequency, amplitude, and phase—can be used to encode data.