| 摘要 |
PURPOSE:To obtain a demodulation circuit with matched impedance by allowing a delay detection mixer to reproduce data from an output signal applying delay detection to the output of a SAW matched filter delayed by a delay line and allowing an absolute value circuit to take an absolute value of a delay detection output signal so as to recover a timing clock. CONSTITUTION:In the demodulation circuit of the spread spectrum modulation system, a spread spectrum signal is given to a SAW matched filter 1, a correlation peak signal from a filter section is delayed via a delay line 2 and the delayed signal is outputted from an output terminal 3 and given to one input terminal 6 of a mixer 5. Furthermore, the correlation signal of the SAW matched filter 1 is given to the other input terminal 7 of the mixer 5. Then the signals are multiplied by the mixer 5, the product,passes through a low pass filter 9 and given to a comparator 10, the output of the comparator 10 is outputted as data and the output of the low pass filter 9 i,s given to a comparator 12 via an absolute value circuit 11 and the output from the comparator 12 is used for a clock signal. |
