Digital dynamic range converter.

摘要

A digital dynamic range converter of the forward control type for varying the dynamic range of an audio signal which is available in digital form and is constituted by a sequence of audio signal samples. In the multiplier device 5, each audio signal sample x(n) is multiplied by a control signal sample s(n) which is delivered by a digital control signal generator 7. This control signal generator 7 has applied to it unipolar signal samples x(n) which are derived by means of a transmission channel 9 from the audio signal samples x(n).

In order to cause this dynamic range converter to respond rapidly to abrupt variations in the audio signal and to render it moreover universally usable, the control signal generator is provided with a digital peak-value detector 11 which converts the sequence of unipolar signal samples x(n) into a sequence of peak-value samples x(n). The latter are applied to an adjustable digital non-linear amplitude transformation circuit 12 which has an adjustable amplitude transmission characteristic curve determined by adjustment quantities R and a. It delivers the transformation samples sin) which are preferably converted in a digital low-pass filter into the control signal samples s(n) which are applied to the multiplier device.