Spread spectrum modulating apparatus using either PSK or FSK primary modulation

摘要

A spread spectrum modulating apparatus includes an oscillator outputting a carrier. A frequency multiplier multiplies a frequency of the carrier by a predetermined integer N1. A frequency divider divides the frequency of the carrier by a predetermined integer N2. A spread code generator uses an output signal of the frequency divider as a clock signal, and generates a spread code in response to the clock signal. A power supply feeds a dc bias voltage. An operation device executes a predetermined logic operation between the spread code and the dc bias voltage of the power supply. A switch selectively feeds an input information signal to either the oscillator or the point of connection of the power supply to the operation device, selecting between PSK and FSK as primary modulation. An output signal of the operation device and an output signal of the frequency multiplier are multiplied to execute a spectrum spreading process.