| 摘要 |
A frequency dependent circuit is located in the main signal path of a dual path compressor or expander in which the main signal path is linear with respect to dynamic range and a further path provides a signal which boosts or bucks the main path by way of a combining circuit, but which is so limited that in the upper part of the input dynamic range the further path signal is smaller than the main path signal. The frequency dependent circuit in the compressor is called an antisaturation network with a characteristic FAS such as to effect a reduction in frequency response in the frequency band affected by overload in a transmission channel fed by the compressor, typically the upper end of the overall frequency band. The expander which is fed by the channel has a complementary antisaturation circuit with a characteristic F'AS providing a complementary increase in frequency response. The arrangement provides level dependent equalization without significantly affecting the noise reduction effect of a compressor/expander system because in dual path compressors and expanders the output of the circuits at very low signal levels is provided mostly by the further path. Thus, at high levels, where channel overload is a problem, the frequency dependent circuit is effective, while at low levels, where it is not desired or needed, the equalization effect is reduced. <IMAGE> |
