Sideband

A graph of that concept, called a Fourier transform (or spectrum), is the customary way of visualizing sidebands and defining their parameters.

Amplitude modulation of a carrier signal normally results in two mirror-image sidebands.

This is sometimes called double sideband amplitude modulation (DSB-AM), but not all variants of DSB are compatible with envelope detectors.

The receiver locally regenerates the subcarrier by doubling a special 19 kHz pilot tone.

In another example, the quadrature modulation used historically for chroma information in PAL television broadcasts, the synchronising signal is a short burst of a few cycles of carrier during the "back porch" part of each scan line when no image is transmitted.

This is common in digital transmission systems such as BPSK where the signal is continually present.

In SSB, the carrier is suppressed, significantly reducing the electrical power (by up to 12 dB) without affecting the information in the sideband.

This makes for more efficient use of transmitter power and RF bandwidth, but a beat frequency oscillator must be used at the receiver to reconstitute the carrier.

The part of the sideband that would overlap the neighboring channel must be suppressed by filters, before or after modulation (often both).

Amateur radio and public service FM transmitters generally utilize ±5 kHz deviation.

To accurately reproduce the modulating waveform, the entire signal processing path of the system of transmitter, propagation path, and receiver must have enough bandwidth so that enough of the sidebands can be used to recreate the modulated signal to the desired degree of accuracy.

In a non-linear system such as an amplifier, sidebands of the original signal frequency components may be generated due to distortion.