modulator (redirected from modulators)

modulator [′mäj·ə‚lād·ər]

(electronics)

The transmitter stage that supplies the modulating signal to the modulated amplifier stage or that triggers the modulated amplifier stage to produce pulses at desired instants as in radar.

A device that produces modulation by any means, such as by virtue of a nonlinear characteristic or by controlling some circuit quantity in accordance with the waveform of a modulating signal.

One of the electrodes of a spacistor.

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Modulator

Any device or circuit by means of which a desired signal is impressed upon a higher-frequency periodic wave known as a carrier. The process is called modulation. The modulator may vary the amplitude, frequency, or phase of the carrier.

There are many ways to accomplish amplitude modulation, but in all cases a nonlinear element or device must be employed. The modulating signal controls the characteristics of the nonlinear device and thereby controls the amplitude of the carrier. See Amplitude-modulation detector, Amplitude modulator

The frequency modulator usually changes the effective capacitance or inductance in the frequency-determining LC circuit of the oscillator. However, other techniques can be used. For example, a multivibrator can be used to generate carrier frequencies up to a few megahertz, and the multivibrator frequency can be modulated by controlling the base, gate, or grid bias supply voltage. See Frequency modulator