Rudolf Goldschmidt
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Rudolf Goldschmidt was a German engineer and inventor, best known for the development of the Goldschmidt alternator radio transmitter, and the tone wheel receiver.
Goldschmidt demonstrating a heart monitor (1927)
Goldschmidt tone wheel used at the Tuckerton, New Jersey transatlantic receiving station.
Beat frequency oscillator
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In a radio receiver, a beat frequency oscillator or BFO is a dedicated oscillator used to create an audio frequency signal from Morse code radiotelegraphy transmissions to make them audible. The signa
Rudolf Goldschmidt
…interrupted the incoming radio signal at a slightly different radio frequency rate than the one used by the transmission. The tone wheel acted as a simple beat frequency oscillator (BFO), and its radio frequency, when combined with the received signal, created an audible "beat" (heterodyne) tone with a frequency that was the…
455 kHz BFO unit for SSB reception
Separate BFO oscillators were manufactured for receivers that didn't have them; a Rohde und Schwarz STI4032 from 1944.