Patent ID: 7433477
Filing Date: 2008-10-07
Classification: H03G

Abstract:
1. A circuit for superpositioning different audio signals of an audio device comprising: more than one audio input channels; a configuration of switches to activate different audio input channels; a configuration of resistors for each audio input channel; an inverting voltage amplifier, having inputs and an output, to control as output stage the superpositioned audio signals without requiring an intermediate stage amplifier wherein a first input of the inverting voltage amplifier is a reference voltage and a second input of the inverting voltage amplifier is connected to a second terminal of an entry resistor and to a means of setting a gain of said amplifier and said output, which is also connected to a means of setting the gain in a feedback loop, can be used to drive a loudspeaker; said entry resistor for said voltage amplifier, wherein a first terminal of said entry resistor is forming a summation point of said audio input channels; and said means of setting the gain of said amplifier.