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The amplifying devices in audio and radio equipment are vulnerable to a variety of feedback problems, which can cause distinctive noise in the output. The term motorboating is applied to oscillations whose frequency is below the range of hearing, from 1 to 10 hertz , [ 3 ] so the individual oscillations are heard as pulses.
The primary concern was the main transmitter, the 416A, which was raised from about 2000 hours when it entered service to about 6 to 8000 hours by 1952, and 20,000 hours by 1967. Likewise, problems with the 417A used in the intermediate frequency pre-amplifier were successfully addressed, raising its useful life from as little as 100 hours to ...
Local oscillators are used in the superheterodyne receiver, the most common type of radio receiver circuit. They are also used in many other communications circuits such as modems, cable television set top boxes, frequency division multiplexing systems used in telephone trunklines, microwave relay systems, telemetry systems, atomic clocks, radio telescopes, and military electronic ...
A radio-frequency power amplifier (RF power amplifier) is a type of electronic amplifier that converts a low-power radio-frequency (RF) signal into a higher-power signal. [1] Typically, RF power amplifiers are used in the final stage of a radio transmitter , their output driving the antenna .
Joint Tactical Information Distribution System Users, 1990. The Joint Tactical Information Distribution System (JTIDS) is an L band Distributed Time Division Multiple Access (DTDMA) network radio system used by the United States Department of Defense and their allies to support data communications needs, principally in the air and missile defense community.
For directional antennas, the Yagi antenna is the most widely used as a high gain or "beam" antenna. For television reception, the Yagi is used, as well as the log-periodic antenna due to its wider bandwidth. Helical and turnstile antennas are used for satellite communication since they employ circular polarization.
In this case, an external push–pull amplifier can be controlled by the current into and out of the operational amplifier. Thus, the operational amplifier may itself operate within its factory specified bounds while still allowing the negative feedback path to include a large output signal well outside of those bounds. [1]
All of these devices took time to operate. Normally the radio operator would first use conventional radio tuners to find the signal in question, either using the DF antenna(s) or on a separate non-directional antenna. Once tuned, the operator rotated the antennas or goniometer looking for peaks or nulls in the signal. Although the rough ...