Large community aerial system - has pilot control circuit for compensation of frequency and temperature dependent attenuation changes

摘要

The attenuation changes affect coaxial cables through which a pilot signal is transmitted; the circuit comprises an equaliser which corrects attenuation-frequency characteristic at an average temperature; a Bode equaliser with at least one controllable impedance is provided; its attenuation in the working frequency range is about proportional to a control signal applied to the variable impedance, so that its attenuation-frequency characteristic compensates that of the cable at least at one temperature; the pilot signal is separated from the Bode equaliser output signal, and a control signal, proportional to the pilot amplitude is delivered. The attenuation-frequency characteristic of the Bode equaliser (27) compensates that of the cable (23) at the mean temperature.