| 摘要 |
A voice detector for supplying a control signal in an automatic telephone answering apparatus in response to a voice signal received from a telephone line. A first one of two parallel signal channels generates a first digital signal for an incoming signal having a minimum amplitude with a minimum duration. The second signal channel generates a second digital signal for an incoming signal having a minimum number of consecutive cycles with periods within a predetermined range corresponding to the frequency range of a ringing signal. A logic element combines the first and second digital signals to produce the control signal if simultaneously the first digital signal is present and the second digital signal is absent. Thereby, the control signal is produced only in response to an incoming voice signal, but not in response to a ringing or a noise signal. |
