A radio communications method includes carrying out, by a transmitter, transmission operations that include generating digital transmission signals carrying symbols to be transmitted and having a predefined time length; and transmitting a radio frequency signal carrying, in successive, non-overlapped time frames or slots having the predefined time length, the digital transmission signals generated. The method further includes carrying out, by a receiver, reception operations that include receiving the radio frequency signal transmitted by the transmitter; processing the received radio frequency signal to obtain a corresponding digital incoming signal; applying an oversampling operation to the digital incoming signal thereby obtaining an oversampled digital incoming signal; detecting successive, non-overlapped time frames/slots with the predefined time length in the oversampled digital incoming signal; and, for each detected time frame/slot, estimating respective symbols carried by the oversampled digital incoming signal in the time frame/slot with a predefined reception matrix incorporating a predefined Kalman filter.

The present disclosure discloses an M-ary DCSK method based on chaotic shape-forming filtering. The method includes the following steps: at S1, parameters of a communication system are set; at S2, HP information and LP information to be sent in each time slot are prepared; at S3, the information to be sent is modulated; at S4, a chaotic carrier is generated through a chaotic shape-forming filter; at S5, a transmitted signal is prepared; at S6, down-carrier frequency and matched filter is performed to a received signal; at S7, the sampling of a maximum SNR point is performed to an output signal of a matched filter; at S8, the decision of high priority information bits is resumed; and at S9, the decision of low priority information bits is resumed.

A communication system comprises a transmitter and a receiver that communicate differential phase modulated data over a wireline channel pair. The transmitter encodes data symbols by generating first and second data signals with differentially phase shifted signal transitions with respect to one another. The receiver receives the first data signal and the second data signal and samples the first data signal based on a signal transition timing of the second data signal to generate a first output data symbol. The receiver furthermore samples the second data signal based on signal transition timing of the first data signal to generate a second output data symbol.

A method of demodulating a signal that is phase modulated to convey R chips having phase transitions between adjacent ones of the R chips to represent chip states, and an overlay symbol spanning the R chips, wherein R>1, and wherein the phase transitions are rotated in a same direction according to an overlay symbol state, comprises: first processing the signal including: accumulating a respective phase of each chip into a respective first chip magnitude, to produce R first chip magnitudes; and accumulating the R first chip magnitudes to produce a first magnitude; second processing the signal including: accumulating a respective phase of each chip into a respective second chip magnitude, to produce R second chip magnitudes; and accumulating the R second chip magnitudes to produce a second magnitude; and determining the overlay symbol state based on the first magnitude and the second magnitude.

The present invention relates to communication technologies and provides a method and a device for FSK/GFSK demodulation, the method comprises: determining a digital information vector group {V.sub.l(i)} of a codeword a[k] to be demodulated and a corresponding phase matching vector group {.sub.i(i)} within the duration of (2M+1)T; determining a received phase vector {tilde over ()}(i) of a received FSK/GFSK baseband signal (t,a); determining an average phase difference .sub.l between {tilde over ()}(i) and .sub.l(i); calculating the phase matching degree Q.sub.l between {tilde over ()}(i) and .sub.l(i) after removing the impact of the average phase difference .sub.l, and determining an l value corresponding to the phase matching degree Q.sub.l being the maximum; and determining the a[k], corresponding to the l value, in the digital information vector V.sub.i(i) as a demodulation result. Because the impact of the average phase difference is removed during phase matching, the accuracy of phase matching is increased, and the performance of the phase domain demodulation technology is improved.

Systems and methods for improved digital RF transport in a DAS are provided. In one embodiment, a transceiver comprises: a receive path circuit including an RF reception interface coupled to an ADC, the ADC receiving a down-converted analog RF spectrum from the RF reception interface and producing a digitized RF spectrum at an input sampling rate; a logic device receiving the digitized RF spectrum and producing a first set of baseband data samples at a first sampling rate, corresponding to a first spectral region of the analog RF spectrum and a second set of baseband data samples at a second sampling rate, corresponding to a second spectral region of the analog RF spectrum. The logic device maps the first set and second sets of baseband data samples to a respective first set and second set of timeslots of a serial data stream transport frame.

The present invention discloses a real-time normalization apparatus and method of the PGC demodulation in a sinusoidal phase modulation interferometer. An optical setup containing a measuring interferometer and a monitoring interferometer is constructed. An electro-optic phase modulator is placed in the common reference arm of the two interferometers. High-frequency sinusoidal wave modulation and low-frequency triangular wave modulation are applied to the electro-optic phase modulator at the same time. Sinusoidal modulation is used for generating phase carrier, and PGC demodulation is performed to obtain quadrature signals containing the phase information to be measured. Triangular wave modulation makes the quadrature signals change periodically. Ellipse fitting is performed on the Lissajous figure corresponding to the quadrature signals, and real-time normalization of the PGC demodulated quadrature signals is achieved. By calculating the variation of the phase difference between the two interference signals, the measured displacement is obtained, and nanometer scale displacement measurement is achieved.

The present invention relates to communication technologies and provides a method and a device for FSK/GFSK demodulation, the method comprises: determining a digital information vector group {V.sub.l(i)} of a codeword a[k] to be demodulated and a corresponding phase matching vector group {.sub.i(i)] within the duration of (2M+1)T; determining a received phase vector {tilde over ()}(i) of a received FSK/GFSK baseband signal (t, a); determining an average phase difference .sub.l between {tilde over ()}(i) and .sub.l(i); calculating the phase matching degree Q.sub.l between {tilde over ()}(i) and .sub.l(i) after removing the impact of the average phase difference .sub.l, and determining an l value corresponding to the phase matching degree Q.sub.l being the maximum; and determining the a[k], corresponding to the l value, in the digital information vector V.sub.i(i) as a demodulation result. Because the impact of the average phase difference is removed during phase matching, the accuracy of phase matching is increased, and the performance of the phase domain demodulation technology is improved.

A method and apparatus are provided for demodulating a wireless signal modulated by phase-shift keying. The signal comprises a plurality of symbols. The method includes: obtaining a first sequence of samples based on the signal; converting the first sequence of samples to a first sequence of frequency domain samples; selecting, as a decision variable, the sample that has the maximum magnitude among the first sequence of frequency domain samples; and identifying a symbol or a symbol-transition based on the decision variable.

The present invention discloses a real-time normalization apparatus and method of the PGC demodulation in a sinusoidal phase modulation interferometer. An optical setup containing a measuring interferometer and a monitoring interferometer is constructed. An electro-optic phase modulator is placed in the common reference arm of the two interferometers. High-frequency sinusoidal wave modulation and low-frequency triangular wave modulation are applied to the electro-optic phase modulator at the same time. Sinusoidal modulation is used for generating phase carrier, and PGC demodulation is performed to obtain quadrature signals containing the phase information to be measured. Triangular wave modulation makes the quadrature signals change periodically. Ellipse fitting is performed on the Lissajous figure corresponding to the quadrature signals, and real-time normalization of the PGC demodulated quadrature signals is achieved. By calculating the variation of the phase difference between the two interference signals, the measured displacement is obtained, and nanometer scale displacement measurement is achieved.