JPS6481538A - Digital spread spectrum signal demodulator - Google Patents

Abstract

PURPOSE:To facilitate the maintenance by constituting a carrier tracing loop and a code tracing loop in parallel so as to simplify the circuit constitution and to reduce number of adjusting positions. CONSTITUTION:An I/F signal subject to spread spectrum modulation is AD- converted by an AD converter 2 by using a sampling pulse of a numeral control oscillator 1 at an AD converter 2 and becomes a signal (b). The output of the oscillator 1 activates generators 3, 4 to generate a sinusoidal and cosine amplitude, a code (c) of a local PM code generator 6 is multiplied with the amplitude, multiplies further the signal (b) to obtain an I data (d) and a Q date (e). Then addition filters 9, 10 are passed through to form a carrier tacing loop. Moreover, the codes h, i of the generator and the multiplication signal of sinusoidal amplitude are multiplied with the signal (b) to obtain an E data (j) and an L data (k) to constitute the code tracing loop 21 through addition type filters 13, 14.