| 摘要 |
PURPOSE:To regenerate a binary signal directly from a signal after continuous phase FSK modulation without generating a ternary signal temporarily and to simplify the hardware of a demodulator by using a delay cosine detector which has one-bit time delay to an input signal and sends out an output signal with a cosine function to the phase of the input signal, and identifies the binary signal directly from the output of this delay cosine detector. CONSTITUTION:The binary signal is modulated by a modulating circuit 2 into a duobinary code. The output signal of this modulating circuit 2 is converted by a continuous phase FSK modulating circuit 3 into a continuous phase FSK signal, which is transmitted from an antenna 5 through a transmitting circuit. A receiver converts the signal received by an antenna 6 into a base-band signal by a receiving circuit 7 and the signal is inputted to the delay cosine detector 8. The output of this detector 8 is supplied to a binary identifying circuit 9 to be regenerated into a binary code, which is outputted. The detector 8 includes a delay circuit 12 which delays the input signal by one-bit time, mixing circuit 13 which multiplies the output signal of the circuit 12 by said input signal, and low-pass filter which extracts a basic frequency component from the output signal of the circuit 13. |
