Beat frequency oscillator
Videos
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
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.
One of the first crude examples of a BFO, the Goldschmidt tone wheel. Before vacuum tube oscillators were invented, the first CW receivers used a wheel with electrical contacts around its rim, spun at a high speed by a motor, to interrupt a current to create a radio frequency signal to beat with the incoming radio signal. This example, at the Tuckerton transatlantic receiving station in New Jersey in 1917, created a 40 kHz signal.
Tonewheel
Videos
A tonewheel or tone wheel is a simple electromechanical apparatus used for generating electric musical notes in electromechanical organ instruments such as the Hammond organ and in telephony to genera
Beat frequency oscillator
…were manufactured for receivers that didn't have them; a Rohde und Schwarz STI4032 from 1944. One of the first crude examples of a BFO, the Goldschmidt tone wheel. Before vacuum tube oscillators were invented, the first CW receivers used a wheel with electrical contacts around its rim, spun at a high speed by a…
Rheotome-cylinders and electric-brushes used on Telharmonium (1896)