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en:bfo [2019/03/28 21:37] (aktuell)
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|+||===== BFO (Beat Frequency Oscillator) =====|
|+||The **Beat Frequency Oscillator** is used to demodulate [[A1|A1 (CW)]] transmissions. In these morse code transmissions, only a carrier signal is transmitted. In a normal AM radio, one would only hear a very slight hiss in the rhythm of the morse code signals, or even nothing.|
|+||So a RF signal very near to the intermediate frequency is added and the mixed signal is demodulated; CW signals are audible as a high pitch tone; in most high grade sets, the BFO frequency and therefore the pitch of the morse code signal is variable.|
|+||The BFO also be activated to demodulate [[SSB|single sideband]] transmissions, the BFO pitch note has to be regulated, so that the human speech sounds natural.|