Patent ID: 7463743
Filing Date: 2008-12-09
Classification: H04R

Abstract:
1. A driving circuit for selectively operating a hands-free loudspeaker and an earpiece speaker of a mobile terminal, comprising: a voiceband electronic circuit that is configured to provide an output on two output ports, wherein a phase of a signal at a first one of the output ports has a defined relationship to that of a signal at a second one of the output ports, the output being switchable between an in-phase mode in which the signals at the first one and second one of the output pods are in phase and an opposite phase mode in which the signals at the first one and the second one of the output ports are in opposite phase; an interconnection means for connecting the earpiece speaker directly to the output on the two output ports of the voiceband circuit; and an adder circuit configured to add the signals supplied by the two output ports and to provide a sum-signal to the hands-free loudspeaker.