Modulation and demodulation method, modulator and demodulator

A modulator comprising:

• a code mapping means for mapping a plurality of data to be transmitted to a code corresponding to a signal point in a signal space;
• an amplitude ratio setting means for providing an amplitude ratio corresponding to said mapped code;
• a n-symbol delay means for providing an instantaneous amplitude at n symbols previously in time (n is a natural number);
• an instantaneous amplitude production means for producing a current instantaneous amplitude based upon a product of the amplitude ratio and the instantaneous amplitude at n symbols previously;
• an amplitude ratio control means for controlling the amplitude ratio to be one of a first amplitude ratio value equal to or smaller than 1 and a second amplitude ratio value equal to or greater than 1 so as to prevent said current instantaneous amplitude from converging to zero and from diverging;
• and
• an amplitude modulation means for modulating a carrier with a radio frequency or an intermediate frequency by said current instantaneous amplitude.

A demodulator comprising:

• an amplitude detection means for detecting an instantaneous envelope level of a received signal;
• a n-symbol delay means for providing an instantaneous envelope level of said received signal at n symbols previously in time (n is a natural number);
• an amplitude ratio calculation means for calculating an amplitude ratio of an instantaneous amplitude in a signal space and an instantaneous amplitude in the signal space n symbols previously in time from said instantaneous envelope level and said instantaneous envelope level at n symbols previously;
• and
• a decision means for deciding a code transmitted in accordance with said calculated amplitude ratio.

A demodulator comprising:

• a logarithmic amplifying means for amplifying a received signal;
• an amplitude detection means for detecting an instantaneous envelope level of the logarithmically amplified received signal;
• a n-symbol delay means for providing an instantaneous envelope level of said logarithmically amplified received signal at n symbols previously in time (n is a natural number);
• an amplitude ratio calculation means for calculating an amplitude ratio of an instantaneous amplitude in a signal space and an instantaneous amplitude in the signal space n symbols previously in time from said instantaneous envelope level and said instantaneous envelope level at n symbols previously;
• and
• a decision means for deciding a code transmitted in accordance with said calculated amplitude ratio.

A modulation and demodulation method for communication between a transmitting side and a receiving side, said method comprising the steps of:

• at the transmitting side, producing a modulating signal, an absolute phase in a signal space of said modulating signal and also an amplitude ratio of a current instantaneous amplitude of said modulating signal and an instantaneous amplitude at n symbols previously in time (n is a natural number) of said modulating signal being set to correspond to a code to be transmitted;
• at the transmitting side, modulating a carrier with a radio frequency or an intermediate frequency by said modulating signal to provide and transmit a modulated signal;
• at the receiving side, receiving the transmitted modulated signal to provide a received signal;
• and
• at the receiving side, deciding the transmitted code from an absolute phase of said received signal in a signal space and from an amplitude ratio of an instantaneous amplitude of a signal point in the signal space and an instantaneous amplitude of the signal point in the signal space n symbols previously in time with respect to said received signal,
• a first amplitude ratio value equal to or smaller than 1 and a second amplitude ratio value equal to or greater than 1 being prepared, said amplitude ratio being selected one of said first and second amplitude values so as to prevent said modulating signal from converging to zero and from diverging.

A modulator comprising:

• a code mapping means for mapping a plurality of data to be transmitted to a code corresponding to a signal point in a signal space;
• a phase setting means for providing an absolute phase corresponding to said mapped code;
• an amplitude ratio setting means for providing an amplitude ratio corresponding to said mapped code;
• a n-symbol delay means for providing an instantaneous amplitude at n symbols previously in time (n is a natural number);
• an instantaneous amplitude production means for producing a current instantaneous amplitude based upon a product of the amplitude ratio and the instantaneous amplitude at n symbols previously;
• an amplitude ratio control means for controlling the amplitude ratio to be one of a first amplitude ratio value equal to or smaller than 1 and a second amplitude ratio value equal to or greater than 1 so as to prevent said current instantaneous amplitude from converging to zero and from diverging;
• and
• an amplitude and phase modulation means for modulating a carrier with a radio frequency or an intermediate frequency by said absolute phase and said current instantaneous amplitude.

A demodulator comprising:

• an amplitude and absolute phase detection means for detecting an instantaneous envelope level in a signal space and an absolute phase in the signal space of a received signal;
• a n-symbol delay means for providing an instantaneous envelope level of said received signal at n symbols previously in time (n is a natural number);
• an amplitude ratio calculation means for calculating an amplitude ratio of an instantaneous amplitude in a signal space and an instantaneous amplitude in the signal space n symbols previously in time from said instantaneous envelope level and said instantaneous envelope level at n symbols previously;
• and
• a decision means for deciding a code transmitted in accordance with said absolute phase and said calculated amplitude ratio.

A demodulator comprising:

• a logarithmic amplifying means for amplifying a received signal;
• an amplitude and absolute phase detection means for detecting an instantaneous envelope level and an absolute phase in a signal space of the logarithmically amplified received signal;
• a n-symbol delay means for providing an instantaneous envelope level of said logarithmically amplified received signal at n symbols previously in time (n is a natural number);
• an amplitude ratio calculation means for calculating an amplitude ratio of an instantaneous amplitude in a signal space and an instantaneous amplitude in the signal space n symbols previously in time from said instantaneous envelope level and said instantaneous envelope level at n symbols previously;
• and
• a decision means for deciding a code transmitted in accordance with said absolute phase and said calculated amplitude ratio.

A modulation and demodulation method for communication between a transmitting side and a receiving side, said method comprising the steps of:

• at the transmitting side, producing a modulating signal, a phase difference between a current instantaneous phase of said modulating signal in a signal space and an instantaneous phase at n symbols previously in time (n is a natural number) of said modulating signal in the signal space and also an amplitude ratio of a current instantaneous amplitude of said modulating signal and an instantaneous amplitude at n symbols previously in time of said modulating signal being set to correspond to a code to be transmitted;
• at the transmitting side, modulating a carrier with a radio frequency or an intermediate frequency by said modulating signal to provide and transmit a modulated signal;
• at the receiving side, receiving the transmitted modulated signal to provide a received signal;
• and
• at the receiving side, deciding the transmitted code from a phase difference between a current instantaneous phase of a signal point in the signal space and an instantaneous phase of the signal point in the signal space n symbols previously with respect to the received signal and from an amplitude ratio of an instantaneous amplitude of the signal point in the signal space and an instantaneous amplitude of the signal point in the signal space n symbols previously in time with respect to said received signal,
• a first amplitude ratio value equal to or smaller than 1 and a second amplitude ratio value equal to or greater than 1 being prepared, said amplitude ratio being selected one of said first and second amplitude values so as to prevent said modulating signal from converging to zero and from diverging.

A modulator comprising:

• a code mapping means for mapping a plurality of data to be transmitted to a code corresponding to a signal point in a signal space;
• a phase difference setting means for providing a phase difference corresponding to said mapped code;
• a first n-symbol delay means for providing an instantaneous phase at n symbols previously in time (n is a natural number);
• an instantaneous phase production means for producing a current instantaneous phase based upon a sum of the phase difference and the instantaneous phase at n symbols previously;
• an amplitude ratio setting means for providing an amplitude ratio corresponding to said mapped code;
• a second n-symbol delay means for providing an instantaneous amplitude at n symbols previously in time;
• an instantaneous amplitude production means for producing a current instantaneous amplitude based upon a product of the amplitude ratio and the instantaneous amplitude at n symbols previously;
• an amplitude ratio control means for controlling the amplitude ratio to be one of a first amplitude ratio value equal to or smaller than 1 and a second amplitude ratio value equal to or greater than 1 so as to prevent said current instantaneous amplitude from converging to zero and from diverging;
• and
• an amplitude and phase modulation means for modulating a carrier with a radio frequency or an intermediate frequency by said current instantaneous phase and said current instantaneous amplitude.

A demodulator comprising:

• an amplitude and phase detection means for detecting an instantaneous envelope level in a signal space and an instantaneous phase in the signal space of a received signal;
• a first n-symbol delay means for providing an instantaneous phase at n symbols previously in time (n is a natural number);
• a phase difference calculation means for calculating a phase difference between said detected instantaneous phase and said provided instantaneous phase n symbols previously;
• a second n-symbol delay means for providing an instantaneous envelope level of said received signal at n symbols previously in time;
• an amplitude ratio calculation means for calculating an amplitude ratio of an instantaneous amplitude in a signal space and an instantaneous amplitude in the signal space n symbols previously in time from said instantaneous envelope level and said instantaneous envelope level at n symbols previously;
• and
• a decision means for deciding a code transmitted in accordance with said calculated phase difference and said calculated amplitude ratio.

A demodulator comprising:

• a logarithmic amplifying means for amplifying a received signal;
• an amplitude and phase detection means for detecting an instantaneous envelope level and an instantaneous phase in a signal space of the logarithmically amplified received signal;
• a first n-symbol delay means for providing an instantaneous phase of said logarithmically amplified received signal at n symbols previously in time (n is a natural number);
• a phase difference calculation means for calculating a phase difference between said detected instantaneous phase and said provided instantaneous phase n symbols previously;
• a second n-symbol delay means for providing an instantaneous envelope level of said logarithmically amplified received signal at n symbols previously in time;
• an amplitude ratio calculation means for calculating an amplitude ratio of an instantaneous amplitude in a signal space and an instantaneous amplitude in the signal space n symbols previously in time from said instantaneous envelope level and said instantaneous envelope level at n symbols previously;
• and
• a decision means for deciding a code transmitted in accordance with said calculated phase difference and said calculated amplitude ratio.

A demodulator comprising:

• means for branching a received signal;
• a differential detection means for detecting a phase difference between an instantaneous phase and an instantaneous phase n symbols previously (n is a natural number) in a signal space of the branched received signal;
• an amplitude detection means for detecting an instantaneous envelope level in the signal space of the branched received signal;
• a n-symbol delay means for providing an instantaneous envelope level of said branched received signal at n symbols previously in time;
• an amplitude ratio calculation means for calculating an amplitude ratio of an instantaneous amplitude in the signal space and an instantaneous amplitude in the signal space n symbols previously in time from said instantaneous envelope level and said instantaneous envelope level at n symbols previously;
• and
• a decision means for deciding a code transmitted in accordance with said detected phase difference and said calculated amplitude ratio.

A demodulator comprising:

• means for branching a received signal;
• a differential detection means for detecting a phase difference between an instantaneous phase and an instantaneous phase n symbols previously (n is a natural number) in a signal space of the branched received signal;
• a logarithmic amplifying means for amplifying the branched received signal;
• an amplitude detection means for detecting an instantaneous envelope level and an instantaneous phase in the signal space of the logarithmically amplified received signal;
• a n-symbol delay means for providing an instantaneous envelope level of said branched received signal at n symbols previously in time;
• an amplitude ratio calculation means for calculating an amplitude ratio of an instantaneous amplitude in the signal space and an instantaneous amplitude in the signal space n symbols previously in time from said instantaneous envelope level and said instantaneous envelope level at n symbols previously;
• and
• a decision means for deciding a code transmitted in accordance with said detected phase difference and said calculated amplitude ratio.