Community antenna system having at least one amplifier

摘要

To be able to retain the drop in carrier level of the first sound subcarrier (1) with respect to the picture carrier (BT), which is usually 16 dB in the two-channel sound transmission for TV in modern community antenna systems, without dropping below the 20 dB of the second sound subcarrier (2) with respect to the picture carrier (BT), a special filter (TF) is placed in the transmission branch. In the simplest case, this filter (TF) consists of a band-pass filter with slightly overcritical coupling with unsymmetric tuning of one stage. This results in the required 4 dB margin between the two sound subcarriers. <IMAGE>