Abstract: An electric low-pass filter with blocking behavior for a predetermined rejection frequency, comprising a series connection including a FIR filter and an IIR filter, with the parameters of the FIR filter being matched in essence with respect to the blocking behavior at the rejection frequency and the parameters of the IIR filter being matched in essence with respect to the low-pass behavior. It is possible with such a filter to obtain good low-pass behavior with very high attenuation of the frequency to be rejected, with relatively low circuit expenditure and high stability with respect to oscillation tendency.

Abstract: A method of signal compression of a signal to reduce the large dynamic range, for example, of the output signal of a CD player in such a way that soft passages of a piece of music are reproduced in somewhat louder manner and very loud passages of a piece of music some are reproduced in somewhat less loud manner. The signal compression circuit used therefor can be integrated completely. The audio signal is fed over a volume control, which can be adjusted by the user, and to this end, a digital setting signal in accordance with the adjustment made on the user side, is supplied via a bus line. When the audio signal is strongly increasing, a tracking signal is formed of said signal, with the amplitude thereof being dependent on the medium amplitude of the audio signal. A window comparator compares the tracking signal with a reference value, as a consequence of which the contents of the up/down counter are reduced. This reduced value is added via an adder to the digital setting signal for the volume control.

Abstract: A method of signal compression of a signal to reduce the large dynamic range, for example, of the output signal of a CD player in such a way that soft passages of a piece of music are reproduced in somewhat louder manner and very loud passages of a piece of music some are reproduced in somewhat less loud manner. The signal compression circuit used therefor can be integrated completely. The audio signal is fed over a volume control, which can be adjusted by the user, and to this end, a digital setting signal in accordance with the adjustment made on the user side, is supplied via a bus line . When the audio signal is strongly increasing, a tracking signal is formed of said signal, with the amplitude thereof being dependent on the medium amplitude of the audio signal. A window comparator compares the tracking signal with a reference value, as a consequence of which the contents of the up/down counter are reduced. This reduced value is added via an adder to the digital setting signal for the volume control.