Abstract: A circuit arrangement for converting of a stereo signal having a mid-plane signal and a side signal into an output signal for each of two audio signal channels. By this circuit arrangement, a simplified and also automatic crosstalk cancellation is possible.

Abstract: An AM demodulator circuit arrangement includes an operational amplifier having at least two alternate input networks and at least two alternate feedback networks which can be selectively activated by switching signals so as to establish an amplifier gain factor having at least two different predetermined values. The switching signals are derived from a square wave clock control signal of a frequency which is an integral multiple of the carrier frequency of the AM input signal supplied to the demodulator. As a result of the periodic variation of the amplifier gain factor, the demodulated signal is produced at the output of the amplifier. Such a demodulator avoids offsets or interference frequencies due to manufacturing tolerances. Sensitivity to interference at higher harmonics of the carrier frequency can be suppressed by appropriate selection of the waveform of the gain factor variation, which is determined by the waveform of the switching signal.

Abstract: The invention relates to a circuit arrangement comprising two identical amplifier circuits which each comprise two cross-coupled transistor pairs. The input signal is applied to the transistor pairs of the two amplifier circuits with equal amplitude but opposite phase, and the output signals are subtracted from each other. As a result the fundamentals and the odd harmonics in the output currents of the two amplifier circuits are added to each other, whereas the even harmonics, in particular the second harmonics, cancel each other.

Abstract: Volume control circuits generally vary the overall gain of a low-frequency amplifier by varying the gain in a negative-feedback branch. At very high gain, at which very large output signals are obtained, the negative-feedback is then very small, which may produce a non-linear distortion. In accordance with the invention the gain of a frequency-compensation stage is varied so that it increases when the overall gain increases. The loop gain at higher output amplitudes is now higher than it would otherwise be so that non-linear distortion is reduced.