| 摘要 |
PURPOSE:To digitize a succeeding demodulator circuit and averaging process circuit by making the modulating frequency band of transmitting carriers sufficiently narrower. CONSTITUTION:Since the frequency band of transmitting signals is narrowed and a receiver is constituted in such a way that the signals received by the receiver are converted into digital signals after they are converted into signals having a sufficiently narrow frequency band, an A/D converter having a low sampling frequency can be used as the A/D converter 28 of the system and a digital delaying device 42 can be used as the succeeding demodulator circuit 40 instead of a one-bit delaying device to be used for performing two-phase DPSK demodulation. Therefore, the devices after the demodulator circuit 40 can be digitized and the constitutions of the A/D converter 28 and demodulator circuit 40 can be simplified. |
