Superheterodyne receiver

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In electronics, a superheterodyne receiver (sometimes shortened to superhet) uses frequency mixing or heterodyning to convert a received signal to a fixed intermediate frequency (IF), which can be more conveniently processed than the original radio carrier frequency. Virtually all modern radio and television receivers use the superheterodyne principle.

Although the superheterodyning principle was quickly adopted for military radios in the 1920's, manufacturers of commercial radios prefered tuned radio frequency receivers; TRF radios were cheaper, easier for a non-technical owner to use, and less costly to operate.

By the 1930's, improvements in vacuum tube technology eroded TRF's cost advantage and the proliferation of radio stations led to greater demand for superheterodyne receivers in commercial radios.