| 摘要 |
A two channel audio switcher includes two analog switches, which may be implemented as a CMOS integrated circuit, receiving at their control input ports a complementary pair of drive signals, typically square wave, so as to toggle their outputs at a supersonic rate, which may be made variable. The switcher may receive as input two channels of a stereophonic source, two independent audio sources or a common monophonic source. The outputs typically drive an audio output unit such as the transmitter of a radio broadcasting system, an audio recording system, or amplifiers, controls and loudspeakers of a sound reinforcement system in an auditorium or studio. The system may be monophonic or stereophonic. In a stereophonic a.m. broadcasting system such as the Kahn independent sideband system, alternate switching allows each sideband to be modulated to full available power, thus allowing an increase in the apparent radiated power. In audio recording, the switcher prevents peak levels of each channel from summing instantaneously and thus enables an increase in the effective recorded level on each channel. In a sound system where the source includes one or more microphones, an auxiliary microphone is made to provide intentional feedback to one channel of the switcher, providing flexibility in processing the toggled feedback to break up standing waves to suppress system feedback "howl", thus increasing the usable acoustic power and improving auditorium coverage.
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