| 摘要 |
PURPOSE:To detect a MODEM training signal by allowing a MODEM signal detector to detect a 2nd signal pattern being the inversion of a 1st signal pattern in succession to a 1st signal pattern in a MODEM training signal. CONSTITUTION:Power is calculated by a signal power calculation section 11 from a reception signal S converted into a digital signal at an A/D converter 10. Moreover, the power of components other than bands of 500Hz, 1700Hz and 2900Hz blocked by a band stop filter 15 is calculated by a signal power calculation section 12 and the power of pass band components through band pass filters 16, 17 is calculated by signal power calculation sections 13, 14. A comparison discrimination section 18 detects the start of MODEM communication and the end of MODEM communication by using output signals S0, R0, W2 of the signal power calculation sections 11-13 and an output signal Y of the band pass filter 17. |
