Discriminator output

In a frequency modulated signal (FM) receiver , the FM modulated signal is demodulated in the discriminator , i. H. converted into the original low frequency signal. In audio receivers, this signal is then amplified so that it is available at the loudspeaker output with the appropriate power. This amplification usually results in distortions ( high-pass , low-pass , de-emphasis , phase distortion ) of the signal, which have no influence on the sound quality, but which make it difficult to use the signals with a digital modem.

If the signal for digital data transmission is to be received with an audio receiver , the corresponding modem must be connected directly to the demodulator output (discriminator output ) without further amplification . Modern amateur radio devices or radio scanners have, in addition to the audio output, an output for connecting digital modems (data output).

The signal level at the discriminator output is usually 0.1 to 0.5 volts (rms).

literature

• Robert Richard Kühn: radio technology. Basics of transmission, reception and radio location technology, Friedrich Vieweg & Sohn Verlag, Braunschweig 1963.
• Jens Johann: Modulation method. Basics of analog and digital transmission systems, Springer Verlag, Berlin / Heidelberg 1992, ISBN 978-3-540-55769-2 .
• Hans-Georg Unger: High-frequency technology in radio and radar. 4th revised and expanded edition, Springer Fachmedien, Wiesbaden 1994, ISBN 978-3-519-30018-2 .