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The receivers were tuned at the pilot's control box by electrical cables and long mechanical tuning shafts, allowing remote control of power, mode, frequency, and volume. AN/ARC-5 set composition and control differed markedly from the earlier systems. Three-unit receiver racks were still predominant, but the receiver line-up was quite different.
ASTEC UM 1286 UHF modulator, top cover taken off. An RF modulator (radio frequency modulator) is an electronic device used to convert signals from devices such as media players, VCRs and game consoles to a format that can be handled by a device designed to receive a modulated RF input, such as a radio or television receiver.
It was used as a local oscillator in some radar receivers and a modulator in microwave transmitters in the 1950s and 1960s, but is now obsolete, replaced by semiconductor microwave devices. In the reflex klystron the electron beam passes through a single resonant cavity. The electrons are fired into one end of the tube by an electron gun. After ...
These terms are traditionally used in connection with radio receivers, but many other systems use many kinds of demodulators. For example, in a modem , which is a contraction of the terms modulator /demodulator, a demodulator is used to extract a serial digital data stream from a carrier signal which is used to carry it through a telephone line ...
DSB-SC is basically an amplitude modulation wave without the carrier, therefore reducing power waste, giving it a 50% efficiency. This is an increase compared to normal AM transmission (DSB) that has a maximum efficiency of 33.333%, since 2/3 of the power is in the carrier which conveys no useful information and both sidebands containing identical copies of the same information.
In the Armstrong method, the audio signal and the radio frequency carrier signal are applied to the balanced modulator to generate a double sideband suppressed carrier signal. The phase of this output signal is then shifted 90 degrees with respect to the original carrier. The balanced modulator output can either lead or lag the carrier's phase.
A tuned radio frequency receiver (or TRF receiver) is a type of radio receiver that is composed of one or more tuned radio frequency (RF) amplifier stages followed by a detector (demodulator) circuit to extract the audio signal and usually an audio frequency amplifier. This type of receiver was popular in the 1920s.
An optical modulator is a device which is used to modulate a beam of light. The beam may be carried over free space, or propagated through an optical waveguide (optical fibre). Depending on the parameter of a light beam which is manipulated, modulators may be categorized into amplitude modulators, phase modulators, polarization modulators, etc.