| 摘要 |
PURPOSE:To save man-power of statistical investigation of service quality and to quicken the service, by automatically discriminating the audible tone on a telephone line. CONSTITUTION:An audible frequency signal to be discriminated which is inputted to a preamplifier 1 is amplified to a required level, split into components per each frequency zone at band pass filter grouos 2, 3, 4, and applied to an audio energy integrator 5. On the other hand, an output signal of the preamplifier 1 is applied also to an input signal detector 6, where the signal is compared with the threshold value indicated in advance by a control section 7, and if the signal level exceeds the threshold value, an input signal detector 6 outputs signal presence information to an audio energy integrator 5. The integrator 5 integrates the signal applied from filter groups 2, 3, 4 with the information given from the detector 6 at the integration time instructed from the control section 7, and it is digitized and transferred to the control section 7. The control section 7 collects and discriminates the information per each filter. |
