| 摘要 |
Apparatus and method for allowing an operator of a transit vehicle to make public address announcements to passengers internal and external to the vehicle. The safety of the vehicle and passengers is maintained through providing a hands-free directional microphone having noise canceling characteristics. The microphone is used as an input device for receiving an audio signal and provides the signal to a processing module that converts the signal into a digital signal. The digital signal is than processed by a digital signal processor to cancel undesirable noise common to a transit vehicle. The noiseless signal can then be converted into an analog signal and recorded within the memory of the public address system where, upon needed, the signal can be transferred to an output device such as a speaker system internal or external to the vehicle. After playback, the recorded message can also be easily repeated by means of a.repeat-switch.
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