US 6,747,524 B2 · Modulator and demodulator

Abstract

A modulator for modulating carrier wave signals with an in-phase component signal and a quadrature component signal includes a fixed frequency signal generator for generating two fixed-frequency signals differing 90 degrees in phase, a variable frequency signal generator for generating a signal whose frequency can be varied according to a modulated signal, in-phase and quadrature component carrier wave signal generators for mixing respective ones of the fixed-frequency signals and the variable-frequency signal to generate carrier wave signals for in-phase and quadrature components, an in-phase component modulator for modulating the in-phase component carrier wave signal with the in-phase component signal, and a quadrature component modulator for modulating the quadrature component carrier wave with the quadrature component signal. Also, a demodulator is able to demodulate an in-phase component modulated signal and a quadrature component modulated signal from the modulator.

Claims9

Dependent claims

A modulator for modulating an in-phase component carrier wave signal with an in-phase component signal and modulating a quadrature component carrier wave signal with a quadrature component signal, the modulator comprising:

fixed frequency signal generating means for generating two signals of fixed frequency differing 90 degrees in phase;
variable frequency signal generating means for generating a signal whose frequency can be varied according to a modulated signal to be produced;
in-phase component carrier wave signal generating means for mixing one signal generated by the fixed frequency signal generating means and the signal generated by the variable frequency signal generating means to generate a carrier wave signal for an in-phase component;
quadrature component carrier wave signal generating means for mixing the other signal generated by the fixed frequency signal generating means and the signal generated by the variable frequency signal generating means to generate a carrier wave signal for a quadrature component;
in-phase component modulating means for modulating the in-phase component carrier wave signal generated by the in-phase component carrier wave signal generating means with the in-phase component signal;
and
quadrature component modulating means for modulating the quadrature component carrier wave signal generated by the quadrature component carrier wave signal generating means with the quadrature component signal.

4 more elements

A communication device equipped with a modulator for modulating an in-phase component carrier wave signal with an in-phase component signal and modulating a quadrature component carrier wave signal with a quadrature component signal and adapted to conduct communication using carrier waves of multiple frequencies, modulate signals with the modulator and transmit the modulated signals,

the modulator of the communication device comprising fixed frequency signal generating means for generating two signals of fixed frequency differing 90 degrees in phase;
variable frequency signal generating means for generating a signal whose frequency can be varied according to a modulated signal to be produced;
in-phase component carrier wave signal generating means for mixing one signal generated by the fixed frequency signal generating means and the signal generated by the variable frequency signal generating means to generate a carrier wave signal for an in-phase component;
quadrature component carrier wave signal generating means for mixing the other signal generated by the fixed frequency signal generating means and the signal generated by the variable frequency signal generating means to generate a carrier wave signal for a quadrature component;
in-phase component modulating means for modulating the in-phase component carrier wave signal generated by the in-phase component carrier wave signal generating means with the in-phase component signal;
and quadrature component modulating means for modulating the quadrature component carrier wave signal generated by the quadrature component carrier wave signal generating means with the quadrature component signal.

3 more elements

Dependencies are inferred from the claim text.

Modulator and demodulator

Life of this patent

Modulator and demodulator

Life of this patent

Abstract

Claims9