| 摘要 |
PURPOSE:To provide a demodulation circuit supplying a stable clock to a spread spectrum modulation demodulator. CONSTITUTION:The demodulation circuit is made up of a SAW matched filter 5 receiving a spread spectrum signal and detecting the correlation, a delay line 6 connecting to the output of the SAW matched filter 5, a mixer 7 whose one input terminal receives the output from the delay line and whose other input terminal connects to the output terminal of the SAW matched filter 5, a low pass filter 8 connecting to the output of the mixer 7, a data comparator circuit 11 connecting to the low pass filter 8, an absolute value circuit 9 generating the absolute value of an input signal connecting to the output of the low pass filter 8, a clock signal comparator 10 connecting to the output of the absolute value circuit 9 and a PLL circuit 30. |
