97 results about "Differential quadrature phase shift keying" patented technology

A high capacity optical transmitter implemented on a photonic integrated circuit chip comprises a single light source which supplies a continuous wave having a particular wavelength to a plurality of modulators to form modulated optical information signals. A phase shifter is coupled to at least one of the modulators and is used to shift the phase of the corresponding modulated optical information signal associated with a particular modulator. A polarization beam combiner receives each of the modulated optical information signals from the modulators and the modulated optical information signal from the phase shifter and combines each of these signals to form a polarization multiplexed differential quadrature phase-shift keying signal. The light source, the plurality of modulators, the phase shifter and the polarization beam combiner are all integrated on the chip.

A method and an apparatus relating to an OFDM data communications system where the sub-carriers are modulated using differential quadrature phase-shift keying (DQPSK). The multi-carrier transmitted signal is directly generated by means of summation of pre-computed sample points. As part of the multi-carrier signal generation, a signal for the guard interval is established. In an acoustic application of this approach, direct radiation of the sub-carrier approach is facilitated. Symbol synchronization in the receiver is based on signal correlation with the missed sub-carrier. Separation of the sub-carriers in the receiver by means of correlation of the received signal and reference signals that are derived from a table of pre-computed values. Optimal non-coherent processing of the sub-carriers without any phase tracking procedures is achieved.

The disclosure is directed toward improved methods and apparatus for producing PSK signals. Commonly, such signals as Differential Quadrature Phase Shift Keying (DQPSK) are produced by coupling the outputs of an encoder to finite impulse response (FIR) filters. The filters shape the path that the signal takes between the transmission of one symbol and the next symbol The present disclosure discloses a method of generating a signal so that the path taken between transmitted symbols is determined by looking up the intermediate values along the path, using a look-up table. An embodiment of the disclosure receives the present symbol and the next symbol to be transmitted and then serially accesses a series of intermediate points comprising a preferred signal path between the present symbol and the next symbol to be transmitted. Commonly some PSK signals are transmitted by processing the phase and the amplitude of the signal separately. In those applications it is common to delay the amplitude portion of the signal in an analog delay line in order to ensure that the recombined signal will have the proper relationship of phase and amplitude. One preferred embodiment adds a phase offset to the phase signal instead of adding a delay to the amplitude signal. Another preferred embodiment performs phase amplitude synchronization by introducing phase offsets in the look-up table values which represent the signal path between sequentially transmitted signals. The phase offset achieves the same result as the traditional amplitude delay mechanism in synchronizing the phase and amplitude portions of the signal without the traditional delay line hardware.

An optical sender is disclosed that operates in a Differential Quadrature Phase Shift Keying modulation scheme for high speed optical transmission and is capable of performing logical calculations at a low speed. The optical sender transmits a Differential Quadrature Phase Shift Keying (DQPSK) signal generated with modulation signals ρ_k and η_k so that a signal directly output from a signal receiver corresponding to the optical sender is in agreement with data signals I_k and Q_k to be transmitted. The signal receiver is capable of modulation by DQPSK, and the modulation signals ρ_k and η_k are precoded by using the data signals I_k and Q_k and the modulation signals one symbol earlier (ρ_k−1 and η_k−1) . The optical sender includes plural precoders that perform logical calculation simultaneously and in parallel on plural data signals one period after another period.

The invention discloses a method and a device for producing a differential quadrature phase-shift keying code optical signal, which belong to the field of communication. The method comprises the steps of: performing light-splitting processing on an optical signal to obtain two polarized light signals; performing modulation and phase-shift processing on one of the polarized light signals to obtain a polarized light signal after the phase shift, and modulating the other polarized light signal to obtain another polarized modulated light signal; performing light combination processing on the polarized light signal after the phase shift and another polarized modulated light signal to obtain a polarization-multiplexed optical signal; and performing polarization processing on the polarization-multiplexed optical signal to obtain the differential quadrature phase-shift keying code optical signal. The device comprises a polarization light splitter, a modulator, a phase-shift controller, a polarization light combiner and a polarizer. The method and the device can steadily produce the differential quadrature phase-shift keying code optical signal through light-splitting processing, modulation and phase-shift processing, light combination processing and polarization processing.

A data-aided, multi-symbol phase estimation (MSPE) scheme is described for improving receiver sensitivity in the direct-detection of optical differential multi-level phase-shift keying (ODmPSK) signals including optical differential quadrature phase-shift keying (ODQPSK) signals, ODQPSK signals with amplitude shift keying (ODQPSK+ASK), optical differential 8-level phase-shift keying (OD8PSK) signals with eight phase levels, and optical differential phase-shift keying signals with more than eight phase levels. The use of data-aided MSPE substantially reduces the “differential detection penalty,” with receiver sensitivity approaching that of coherent detection schemes.

The invention relates to a receiving device of difference orthogonal phase shift keying DQPSK signals and a method thereof, wherein the device comprises a splitter, wherein the splitter is connected with two optical band pass filters and the two optical band pass filters are respectively connected with a photodetector. DQPSK signals are filtered and demodulated through the optical band pass filters, photoelectric conversion is carried out through the photodetector to restore data signals, which not only avoids the problems of bad stability and polarization independence due to MZI, but also greatly improves the performance of an optical transmission system, simultaneously, the transmission rate of the DQPSK signals is higher, the operation of the optical band pass filters is easier, the problem that the manufacture of the MZI has high difficulty along the improvement of the signal transmission rate is solved, and the cost of the DQPSK signal receiving device is greatly saved. The method is used to demodulate the DQPSK signals through filtering, and the problems of complex demodulation, bad transmission performance and high cost due to the MZI are solved.

The present invention utilizes field programmable gate arrays (FPGAs) to implement a parallel differential quadrature phase shift keying (DQPSK) precoder and a DQPSK optical transmitter with an automatic realignment process. The present invention can perform DQPSK preceding, modulation, and data stream realignment at any lower rate, and its upper rate is determined by capability in speed and logic resources and external connections of available integrated circuit technology.

The invention provides a monolithic integrated orthogonal balanced light detector, which comprises two double-balanced polarization light detectors and a biasing circuit of the double-balanced polarization light detectors, wherein the double-balanced polarization light detectors can be used for detecting transverse electric (TE) and transverse magnetic (TM) polarized light. The orthogonal balanced light detector can be used as a core device of an orthogonal balanced receiver for detecting differential phase shift keying (QPSK)/ differential quadrature phase shift keying (DQPS) signals. The biasing circuit comprising an on-chip capacitor, a high-frequency current suppressing resistor and a load resistor is also integrated in the device. The detector has light signal polarization selectivity, so a polarizing beam splitting mirror is not needed, the size of a light receiver can be greatly reduced, the work speed of the device is accelerated, and the reliability of the device is improved.

A differential quadrature phase shift keying (DQPSK) system, method, and device are disclosed. The DQPSK system includes: a transmitter, configured to: pre-code an input first signal and second signal, and generate an in-phase signal and a quadrature signal; modulate the in-phase signal to generate a first differential phase shift keying (DPSK) signal, and modulate the quadrature signal to generate a second DPSK signal; perform a 90 degree phase shift on the first DPSK signal or the second DPSK signal, and interfere with the other DPSK signal to obtain a DQPSK signal; and send the DQPSK signal to a receiver; the receiver, configured to: demodulate the DQPSK signal sent from the transmitter in detuned filter mode, and restore the first signal and the second signal through optical/electrical (o/E) conversion. With the present invention, the accurate control on the phase difference between two arms of an Asymmetric Mach-Zehnder Interferometer (AMZI) is avoided, thus facilitating the signal control and adjustment, and greatly lowering the system cost.

The invention provides a carrier communication multi-service access platform system. The carrier communication multi-service access platform system comprises at least one piece of carrier communication equipment which serves as a node to form a communication network, wherein an orthogonal frequency division multiplexing (OFDM) technology with differential binary phase shift keying (DBPSK), differential quadrature phase shift keying (DQPSK) and differential 8-ary phase shift keying (D8PSK) modulation and forward error correction, a self-adaptive carrier frequency selection technology and a programmable trapped wave mechanism are adopted among the nodes; cross transformer data transmission is performed through a medium/low voltage distribution wire; and the at least one piece of carrier communication equipment is communicated with external network equipment and/or a server through a data interface. The invention also provides a carrier communication multi-service access method. The invention can be applied to data transmission of power wires of power distribution networks with medium voltage of 10 to 35 KV and low voltage of 380 to 220 V, has multiple bus modes, is convenient with the external network equipment or server conveniently and can adopt a network structure with a master and multiple slavers. The main node has a network management function, can realize full-carrier network node management and is flexible in networking mode.

The invention discloses an FPGA (Field Programmable Gate Array)-based multimode demodulating system, belongs to the technical field of communication, and aims to solve the problems of waste of hardware resources and low universality in an existing hardware platform based on software radio. The FPGA-based multimode demodulating system comprises a DPSK/DQPSK (Differential Phase Shift Keying/Differential Quadrature Phase Shift Keying) demodulating module, an FSK (Frequency Shift Keying) demodulating module and a dynamic switching module which are implemented on the basis of an FPGA; the DPSK/DQPSK demodulating module is based on the FPGA, and used for realizing DPSK demodulation and DQPSK demodulation; the FSK demodulating method is based on the FPGA, and used for realizing FSK demodulation; the dynamic switching module is used for realizing switching among the DPSK demodulation, the DQPSK demodulation and the FSK demodulation through the FPGA; and the FPGA is an FPGA obtained after reconstruction of a dynamic part of the FPGA through a Microblaze soft-core processor. The FPGA-based multimode demodulating system is applied to demodulation in a communication receiver.

The invention relates to a monolithically integrated multi-wavelength differential quadrature phase shift keying (DQPSK) demodulator and a manufacturing method thereof. The demodulator is provided with a 1*D wavelength division demultiplexer and D DQPSK demodulators which are integrated on the same waveguide substrate to form a waveguide structure chip. The method comprises the following steps of: monolithically integrating the wavelength division demultiplexer AWG and a plurality of multi-wavelength optical DQPSK demodulators with delay line interferometers on the same waveguide substrate by planar optical waveguide technology to manufacture the waveguide structure chip; manufacturing a metal film micro-heater on one of two arms of each optical delay line interferometer forming the DQPSK demodulator by a photoetching, sputtering and stripping semiconductor process to realize phase control; adhering a thermoelectric cooler (TEC) to a chip substrate to control the temperature of the whole chip; and respectively connecting the metal film micro-heater and the TEC with an error signal from a control feedback loop. The DQPSK demodulator has low cost, the process is simple and the method contributes to mass production.

The invention relates to a multi-speed difference quadrature phase shift keying demodulator and a control method thereof. The demodulator comprises more than one first equipartition coupler, second equipartition coupler and third equipartition coupler sequentially arranged on the light path of a chip of the demodulator, first directional couplers and second directional couplers corresponding to the output of each second equipartition coupler or third equipartition coupler, first metallic film heaters and first thermistors arranged on lower arms between the second equipartition couplers and the first directional couplers, second metallic film heaters and second thermistors arranged on the lower arms between the third equipartition couplers and the second directional couplers, third thermistors arranged on the chip of the demodulator, and a microprocessor connected to the chip of the demodulator. The temperature TTEC (Temperature of Thermal Electrical Cooler) of a TEC (Thermal Electrical Cooler), the temperature TI of the metallic film heater 5 and the temperature TQ of the metallic film heater 6 are respectively configured according to different signal rates when the devices utilize different signal speeds in different transmission networks, thus the invention is adaptive to the application of the different transmission rates in the different transmission networks.

A delay-line demodulator for demodulating a differential quadrature phase shift keying (DQPSK) signal is provided. The demodulator includes two Mach-Zehnder interferometers individually comprising two waveguides having different lengths therebetween and through which a light signal branched from the DQPSK signal propagates, respectively. A phase of the light signal propagating at one of the waveguides is delayed as compared to a phase of the light signal propagating at another one of the waveguides, wherein a divergence amount of polarization is adjusted by driving sets of heaters that are facing each other and sandwiching a half wavelength plate therebetween.

The embodiment of the invention relates to the field of communication transmission, and particularly discloses methods, devices and systems for generating and receiving difference quadrature phase shift keying (DQPSK) codes. The device for generating the difference quadrature phase shift keying (DQPSK) codes comprises a laser, a time division multiplex device, a precoding unit, a first control unit, a delay adjustable unit, a third delay adjustable unit and a double parallel modulator. The device for receiving the difference quadrature phase shift keying (DQPSK) codes comprises an optical splitter, a second control unit, a first interferometer, a second interferometer, a first balance receiver, a second balance receiver and a time division multiplex device. By adopting the technical scheme of the embodiment of the invention, the nonlinear effect of signals in the optical fiber transmission is reduced, and the optical transmission performance is improved.

The invention relates to the field of optical communications, in particular to a bias point control device and method of a DQPSK (Differential Quadrature Phase Shift Keying) demodulator, which can accurately acquire the minimum value of a peak value detection signal and lock the DQPSK demodulator to an accurate bias point. The device comprises a sampling resistor, a peak value detector, a DLI (Data Link Interface) locking controller, a driver and a pi/2 driver, wherein the peak value detector is used for acquiring a voltage peak value signal of a voltage signal according to the voltage signal collected by the sampling resistor, the DLI locking controller is connected with the output end of the peak value detector and outputs a periodic bias point control voltage signal, the input end of the driver is connected with the output end of the DLI locking controller and used for adding the periodic bias point control voltage signal to an I-path signal or Q-path signal of the DQPSK demodulator, the pi/2 controller is used for adding a third bias point control voltage signal to the Q-path signal of the DQPSK demodulator and controlling the phase difference between the I-path signal and the Q-path signal of the DQPSK demodulator to be pi/2.

The invention discloses a coherent demodulation device of non-geostationary orbit satellite DQPSK (Differential Quadrature Phase Shift Keying) communication. The coherent demodulation device is used for carrying out down-conversion and lowpass filtering on initial signals output by a receiving antenna and a radio frequency system, and then Doppler frequency shift is eliminated through revolution de-differential operation. After the de-differential is completed, the signals are sent to a bit synchronization loop to complete bit synchronization, and then sent to a phase locked loop for carrier phase tracking, so that coherent demodulation is realized.

In some aspects, the disclosure is directed to methods and systems for an enhanced data rate, low energy wireless communication. Devices may communicate over predetermined wireless bands such as the 2.4 GHz and 5 GHz ISM bands, using π/4-differential quadrature phase shift keying, with physical layer rates of 1, 2, 4, 8 Mbps or higher. Symbol timing may be at any frequency, and may be 256 ns in some implementations. In some implementations, to extend device battery life, devices may use a low latency reconnect mechanism allowing frequent hibernation or shutdown of transmitters and/or carriers.

A colorless optical DQPSK demodulator and system operating over multiple, equally-spaced DWDM channels with fixed optical delays—capable of demodulating DQPSK within signals within DWDM communications wave bands on ITU grids using delay interferometers having fixed free spectral range at 20 GHz or 25 GHz.