SPREAD SPECTRUM SIGNAL DEMODULATION CIRCUIT

摘要

PURPOSE:To simplify the circuit constitution by holding a value relating to an output of a filter means at a different time and comparing held values so as to control the oscillating frequency of a frequency variable oscillator. CONSTITUTION:A 1st holding circuit 119 and a 2nd holding circuit 121 hold a level of an integrated output of an envelope detector 111 at a different time respectively as a digital data by holding an output of a digital integration circuit 118 section with the 1st holding circuit 119 and the 2nd holding circuit 121. An integration value data held in the 1st holding circuit 119 and an integration data held by the 2nd holding circuit 121 are both inputted to a comparator circuit 122. A current integration value and a just preceding integration value are compared by the comparator 122 and an oscillating frequency of a VCO 102, that is a phase of a demodulated N code from a PN code generator 108 is controlled based on the result of comparison.