| 摘要 |
PURPOSE:To attain accurate demodulation even at high speed transmission, by sampling an FSK-modulated signal twice and providing a filter passing through a spectrum corresponding to prescribed space frequency and a mark frequency. CONSTITUTION:A signal inputted to a terminal 1 is sampled at an A/D converter 2 in equal time intervals T. This signal is sampled at a sampling circuit 11. The 2nd sampling is executed in an integer multiple of the 1st frequency. Harmonic spectrums generated at the circuit 11 are picked up at a high pass filter 12. Resulting from the fact, the spectrum corresponding to the space and the mark frequencies are brought to a high frequency. Since the carrier signal is separated at a low pass filter easily, the operation of a band path filter separating the sapce from the mark is made stable. |
