Demodulation

Demodulation is the recovery of the useful signal in the baseband, which has been previously modulated by modulation on a carrier.

This is dependent on the modulation and on the occupancy of the frequency band with parallel transfer, knowledge of certain parameters of the carrier ( for example, frequency, phase angle) of the modulation (e.g., modulation index ) and the useful signal (bandwidth, if necessary, symbol rate ) is necessary. For stable parameter ranges a one-time notification, less stable must be determined from the received RF signal. Help remaining shares of the carrier, pilot tones, zero symbols.

The useful signal in the baseband can be represented differently in the receiver than the transmitter, such as a history of a Tastverhältnises or sequence of binary coded numbers instead of a voltage waveform.

Circuits for demodulation are called demodulator. Circuits containing both the modulator and demodulator, called abbreviated modem.

For the history, significance and methods, see modulation.

• Modulation (technology)