| 摘要 |
Fig. 1 illustrates the construction of an audio signal processor according to the present invention. An audio signal enters from a microphone 1 and a bandpass filter 2 extracts the frequency band of the human voice. The resulting signal is amplified by an amplifier 3. A level detecting circuit 4 detects the level of the amplified signal. A level discriminating circuit 5 determines if the level is greater than the value. If yes, the circuit 5 outputs a switch-on signal. Or else, the circuit 5 outputs a switch-off signal. An A/D converter 6 converts the analog signal entering from the circuit 5 into a digital signal. A pitch detecting circuit 7 detects the pitch of the digital signal. A pitch discriminating circuit 8 determines if the pitch of the signal agrees with a prescribed pitch. If yes, the circuit 8 outputs the switch-on signal to the voice-output control switch 13. On the basis of the switch-on or switch-off signal, the switch 13 generates an on/off control signal, which causes a voltage-controlled amplifier 9 to amplify and output the voice signal and output to a mixer 10. Voice processing circuits S and S' are identical in construction. Microphones 1, 1' of the processing circuits S, S' are connected to a mixer 10. The latter mixes the audio outputted by the microphones 1, 1'. An amplifier 11 amplifies the mixed voice signals. A speaker 12 outputs the audio. <IMAGE> |
