Cordless telephone station with two parallel loudspeakers - has two series phase-opposition microphones, in transformed link with phase-opposition loudspeakers preventing acoustic feedback

摘要

The telephone station has two loudspeakers with their sound outlet holes facing one another. The sound level in the centre between the two loudspeakers (L1,L2) extinguished by driving the loudspeakers in phase opposition in parallel to one another. The sound response level of the station is increased by connecting two microphones in phase opposition in series. The loudspeakers and the microphones (M1,M2) are connected to operation amplifiers supplied from a shared supply. Acoustic feedback is avoided and the range of the microphones increased.