Search results
Results from the WOW.Com Content Network
A 5-tube superheterodyne receiver manufactured by Toshiba circa 1955 Superheterodyne transistor radio circuit circa 1975. A superheterodyne receiver, often shortened to superhet, is a type of radio receiver that uses frequency mixing to convert a received signal to a fixed intermediate frequency (IF) which can be more conveniently processed than the original carrier frequency.
That circuit is called the mixer. The result is a fixed, unchanging intermediate frequency, or I.F. signal which is easily amplified and detected by following circuit stages. In 1919, Armstrong filed an application for a US patent of the superheterodyne circuit which was issued the next year. This patent was subsequently sold to Westinghouse. [24]
Superheterodyne transmitter is a radio or TV transmitter which uses an intermediate frequency signal in addition to radio frequency signal. Types of transmitters
Besides its use in the superheterodyne circuit found in almost all radio and television receivers, it is used in radio transmitters, modems, satellite communications and set-top boxes, radar, radio telescopes, telemetry systems, cell phones, cable television converter boxes and headends, microwave relays, metal detectors, atomic clocks, and ...
The term All American Five (abbreviated AA5) is a colloquial name for mass-produced, superheterodyne radio receivers that used five vacuum tubes in their design. These radio sets were designed to receive amplitude modulation (AM) broadcasts in the medium wave band, and were manufactured in the United States from the mid-1930s until the early 1960s.
The increased complexity of the superheterodyne circuit compared to earlier regenerative or tuned radio frequency receiver designs slowed its use, but the advantages of the intermediate frequency for selectivity and static rejection eventually won out; by 1930, most radios sold were 'superhets'.
Most superheterodyne receivers designed for broadcast FM (88 - 108 MHz) use an IF of 10.7 MHz. TV receivers often use intermediate frequencies of about 40 MHz. Some modern multiband receivers actually convert lower frequency bands first to a much higher frequency (VHF) after which a second mixer with a tunable local oscillator and a second IF ...
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 ...