| 摘要 |
PURPOSE:To improve remarkably the detecting accuracy of a PB signal by detecting a digital PB signal after a digital signal from a time division multiplex switch is processed as it is so as to eliminate the need for inverting the signal into an analog signal once. CONSTITUTION:A parallel signal (digital signal) transmitted from a time division multiplex switch TDSW1 and a serial/parallel converting circuit S/P2 is subject to digital signal processing at a digital filter circuit DFIL6 such as multiplication, addition and delay to attain filtering with high accuracy. Then a digital PB signal detecting circuit DDET7 detects the digital PB signal from an output signal of the said DFTL6. Thus, it is not required to invert the digital signal into an analog signal once thereby improving remarkably the detecting accuracy of the PB signal. |
