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Superette (radio)
In 1931 RCA introduced a new line of Superette radio receivers. These used the superheterodyne principle but were lower cost than earlier products, in an attempt to maintain sales during the onset of the Great Depression. Background Edwin Howard Armstrong invented the superheterodyne receiver in 1918. Armstrong and RCA (under David Sarnoff) had a business and technical relationship, that would last into the 1940s. Funded by RCA, Armstrong designed a radio that can receive stations easily without complex tuning or interference from other stations. Early radio designs by Armstrong and others produced radios that were very sensitive but hard to keep under control due to the nature of radio waves operating at higher frequencies. Armstrong's superheterodyne receiver converted these high frequencies into one lower frequency. This allow the radio to be more stable or easier to tune, with less interference. The result was the RCA Radiola AR-812 and Radiola VIII Superheterodynes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superheterodyne
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. It was long believed to have been invented by US engineer Edwin Armstrong, but after some controversy the earliest patent for the invention is now credited to French radio engineer and radio manufacturer Lucien Lévy. Virtually all modern radio receivers use the superheterodyne principle; except those software-defined radios using ''direct sampling''. History Heterodyne Early Morse code radio broadcasts were produced using an alternator connected to a spark gap. The output signal was at a carrier frequency defined by the physical construction of the gap, modulated by the alternating current signal from the alternator. Since the output frequency of the alternator was generally in the audible range, this produces an audible a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
