1556 results about "Modulation demodulation" patented technology

Systems, apparatus, and methods for new generations of wireless systems, including multiple standard, interoperable Third-Generation (3G) and Second-Generation (2G), Spread Spectrum CDMA, WCDMA, GSM, Enhanced GSM systems and CSMA, TDMA and OFDM. Bit Rate Agile (BRA), Modulation and Code Selectable processing techniques of Gaussian Minimum Shift Keying (GMSK), Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM), and of Mis-Matched demodulator filters in which the demodulator filter set is mismatched to the filter set of the signal modulator.

An illuminating light communication device, which is for establishing a communication system capable of controlling fluctuation in intensity of illuminating light when transmitting data using a power line and illuminating light, and satisfactorily carrying out communication using the power line and communication using the illuminating light, is provided. When data is transmitted through the power line, a signal component is extracted by a filter unit 12, and the demodulated by a power line modulator-demodulator 13, thereby retrieving the data. The retrieved data is temporarily stored in a protocol converter 14. Afterward, the data is converted to the optical communication protocol, and blinking or amount of light of a semiconductor light emitting element 16 is controlled according to the data transmitted from a light source control unit 15, thereby modulating the illuminating light. This allows transmission of data utilizing the illuminating light. Multiple-valued PPM, which defines that existing pulses correspond to OFF while no pulse corresponds to ON, may be used as a modulation system for optical communication.

Method and process for receiving, demodulating, equalizing and processing of Modulation Demodulation Format Selectable (MFS) received signal, received from two or more than two antennas and from diversity receivers. Baseband processing filtering and adaptively equalizing demodulated signals and providing filtered equalized burst operated Time Division Multiplexed (TDM) cross-correlated in-phase and quadrature phase signal, spread spectrum Code Division Multiple Access (CDMA) signal and Orthogonal Frequency Division Multiplexed (OFDM) signals. Demodulation of peak limited cross-correlated OFDM signals. Demodulation and adaptive equalization of receive filtered signal, wherein the received filtered signal is mis-matched to transmit filtered signal. Process for receiving and demodulating MFS signals received from modulated linearly amplified and transmit filtered modulated non-linearly amplified (NLA) signal transmitters. Demodulation and processing of cross-correlated TDM, spread, spectrum and OFDM signals.

The present invention relates to a space form detection device of fine-long flexible bar and its detection method. Said device is composed of fine-long flexible bar, fiber-optic grating sensor array, fiber-optic grating modulator-demodulator, local area network router, data acquisition and data processing module and display equipment. The space form detection method of fine-long flexible bar includes the following steps: utilizing a group of grating array formed from four optical fibers arranged on the fine-long flexible bar, utilizing scale factor between the off-line labeled curvature and wavelength and utilizing fiber-optic grating modulator and demodulator to measure wavelengths of 20 raster points in five discrete points of fine-long flexible bar in the space so as to obtain the space curvature size and direction of discrete point position, then utilizing data processing module to reconstruct the form of said fine-long flexible bar in space. Said device can be used for making real-time tracking detection of human body cavity channel and fine-small vessel forms in the therapeutic process.

Modulation-demodulation format selectable (MFS) processor, cross-correlator and transmit filter for processing, cross-correlating and filtering in-phase and quadrature-phase baseband signal and providing a first bit rate and a second bit rate baseband signal to a modulator and a transmitter for modulation and transmission of the processed filtered baseband signal. Transmit amplifier operated in a first radio frequency (RF) band for amplification of the first bit rate modulated signal and a second RF amplifier operated in a second RF band for amplification of the second bit rate modulated signal. Switch for selecting the first or the second bit rate or first or second modulation format signal and providing selected signal to a transmitter. Receiver for receiving transmitted signal. Demodulator and demodulator filter mismatched to transmit baseband filter. Receive processor for receiving and processing quadrature demodulator demodulated baseband filtered signal and for providing first and second format cross-correlated in-phase and quadrature-phase baseband signal. Time division multiplex (TDM) and Orthogonal Frequency Division Multiplex (OFDM) processor and transmit baseband filter for processing, filtering and providing TDM and OFDM processed and filtered signal to a modulator, transmitter and receiver. Receiver and demodulator for demodulating and baseband filtering received modulated TDM signal. Demodulator of TDM signal has a demodulator baseband filter which is mismatched to the transmit baseband filter and provides demodulated baseband mismatched filtered cross-correlated in-phase and quadrature-phase signal.

The invention discloses a multi-band frequency spectrum aggregating wireless transmitter-receiver device which is characterized in that multi-band simulating radio frequency front ends are aggregated; different radio frequencies are divided into 20 MHz and 60 MHz processing frequency bands; analog-to-digital conversion while receiving a base-band signal and digital-to-analogue conversion while sending are performed in low and intermediate frequencies; and a signal treatment relative to a base-band NC-OFDM modulation-demodulation is performed by a sending base-band processing channel and a receiving base-band processing channel which are dynamically arranged. The invention solves the problem that the prior mobile communication terminal cannot work in multi-band at the same time during the communication process and only can use continuous frequency spectrums. The frequency spectrum aggregating function of the transmitter-receiver device realizes a data rate required by an IMT-Advanced system.

The embodiment of the invention discloses a method, a system and a terminal capable of improving the safety of a trusted execution environment. The method comprises the following steps of: acquiring the connection request initiated by a trusted application to a target server, the connection request containing the identification of the target server; acquiring a server list stored in a smart card through a modulator-demodulator; judging whether the target sever is contained in the server list according to the identification of the target server; if so, then allowing the trusted application to establish connection with the target server, or else, then refusing the trusted application to establish connection with the target server. The embodiment of the invention is capable of improving the safety of the TEE through the smart card.

Disclosed is a digital television system carrying out modulation/demodulation by VSB (vestigial side band) . A VSB transmitter includes an additional error correction encoder designed in a manner that a signal mapping of a TCM encoder is considered, a multiplexer (MUX), a TCM encoder operating in a manner corresponding to state transition processes of the additional error correction encoder, and a signal transmission part including an RF converter. And, A VSB receiver includes a signal receiver part receiving a signal transmitted from the transmitter, a TCM decoder, a signal processing part including a derandomizer, and an additional error correction decoder part.

A mechanical quantity measuring apparatus is provided which can make highly precise measurements and is not easily affected by noise even when it is supplied an electricity through electromagnetic induction or microwaves. At least a strain sensor and an amplifier, an analog/digital converter, a rectification/detection/modulation-demodulation circuit, and a communication control circuit are formed in one and the same silicon substrate. Or, the silicon substrate is also formed at its surface with a dummy resistor which has its longitudinal direction set in a particular crystal orientation and which, together with the strain sensor, forms a Wheatstone bridge. With this arrangement, even when a current flowing through the sensor is reduced, measured data is prevented from being buried in noise, allowing the sensor to operate on a small power and to measure a mechanical quantity with high precision even when it is supplied electricity through electromagnetic induction or microwaves.

The invention is DCPL field bus of network intelligent meter gauge end. The host connects with several field slave machines which are several network intelligent water meter end, gas meter end and home distribution end respectively. Connects several field slave machines and addressing remote digital correspondence function through a twisted pair line, and provides the field bus of direct current power. The network prepaying bridge sets CPU, data storing chip, analog switch, displaying circuit, light coupler and correspondence chip connected through MODEM chip, the CPU also connects with radiofrequency read/write model, the user forms outdoor card brushing information interactive. The host of bridge connects with DCPL field bus ports of slave machines; connects with RS485 or CAN bus portsof housing estate managing computer. The IC card is brushed without contact through bridge, and the data are transmitted to user network intelligent meter gauge end through DPCL.

An efficient system and method for modulation and demodulation to achieve a high data rate using Bit-Interleaved Coded Modulation and OFDM uses either a coherent or a non-coherent transmission scheme using differential modulation. In order to maintain a high data rate impervious to sudden phase changes, a communication system uses an efficient constellation having multiple rings with different sizes and modulation/demodulation schemes utilizing this constellation. In power line communications, the channel gain information is obtained easily at a receiver (100) while the phase information is not. Thus, the communication system uses an absolute magnitude and differential phase coding for modulation and demodulation of the signals.

The invention relates to an underwater communication system. The underwater communication system comprises a sensor, a transmitting sub-system and a receiving sub-system, wherein the sensor is used for sensing an external environment, and assisting an underwater wireless communication node in automatically selecting a proper communication mode and a corresponding modulation-demodulation mode; the transmitting sub-system consists of an encoding unit, an adaptive modulation unit and an transmitting unit; the transmitting sub-system is used for transmitting a signal to be transmitted to a corresponding channel of the transmitting unit after the signal is encoded by the encoding unit and demodulated by the adaptive modulation unit, and converting an electric signal into an acoustic signal or an optical signal to transmit the acoustic signal or the optical signal; the receiving sub-system consists of a receiving unit, an adaptive demodulation unit and a decoding unit; and after a corresponding channel of the receiving unit receives the acoustic signal or the optical signal and converts the acoustic signal or the optical signal into the electric signal, the electric signal is demodulated by the adaptive demodulation unit, and an original signal is demodulated by a decoder of the decoding unit lastly. Through adoption of the underwater communication system, reliable transmission of data or instructions within a communication network range is realized.

The invention provides a method for acquiring parameters of a permanent magnet synchronous motor (PMSM), which comprises the following steps: measuring direct-current bus voltage; controlling an inverter to output current to the PMSM by adopting a digital hysteresis loop-type pulse modulation demodulation control mode; detecting line voltage and phase current which correspond to input current in the PMSM; and calculating the stator resistance of the PMSM, the magnetic induction strength psif of a permanent magnet excitation flux linkage and/or the inductance value Ld of the d axis and the inductance value of the q axis according to different current output to the PMSM under controlling the inverter. By adopting the method for acquiring parameters of the PMSM, three parameters in the PMSM are accurately calculated, and the control effect of the vector control technology on the PMSM is effectively improved.

An anti-phase noise amplitude phase combined keying modulation and demodulation method belongs to the technical field of modulation and demodulation, the method is characterized in that, a circular constellation diagram construction method and a circular constellation diagram selection method are firstly utilized for designing a constellation diagram structure with good symbol error performance; secondly, a bit mapping algorithm which is proposed by the invention is utilized for solving the difficulty of carrying out the Gray-code mapping of other constellation diagrams except the quadrature amplitude modulation (QAM), thereby ensuring the bit error performance of the proposal; the demodulation proposal with high reliability and low complexity is further matched for use, the actual bit error performance is not only far better than the QAM which uses the Gray codes under the phase noise, but also has no obvious loss compared with the Gray-code QAM when in only consideration of Gaussian white noise; finally, the design method which is proposed by the invention is simple and easy to operate, thereby being easily expanding to any order, facilitating the application in a communication system with serious phase noise of global digital broadcasting and the like and possibly reducing the costs and the complexity of a receiver at the same time of ensuring the symbol error performance of the system.

The invention provides a liftable communication relay system and method for information interaction between underwater users and a ground control center. The liftable communication relay system comprises an antenna cabin for information transmission and receiving between the underwater users and the ground control center, a relay control cabin for controlling upward floating or downward diving of the antenna cabin under the water and managing underwater and ground users, and a lifting device for specifically carrying out lifting actions of the antenna cabin, wherein the antenna cabin comprises a first water sound modulator-demodulator and a satellite communication terminal at the top of the antenna cabin. The first water sound modulator-demodulator and the relay control cabin located under the water perform bidirectional wireless water sound communication, and the satellite communication terminal and the ground control center perform data or instruction interaction in a wireless mode. The lifting device achieves upward floating or downward diving of the antenna cabin under the water under the control of the relay control cabin. The relay control cabin manages data transmission among the underwater and ground users and monitors the depth and posture data of the antenna cabin through water sound wireless communication to control work and stopping of the lifting device.

The invention provides a deep-sea observing buoy system based on inductive coupling and satellite communication techniques and belongs to the technical field of an ocean buoy platform. The deep-sea observing buoy system comprises a data collecting control satellite communication subsystem, a shore-station satellite communication subsystem, a power supply subsystem, a buoy subsystem and a mooring subsystem. A principle of a transformer is adopted by the deep-sea observing buoy system; an underwater plastic coated steel cable is taken as an iron core of the transformer, an inductive coupling connector is taken as a primary coil, the coils in various data sensors under the water are taken as secondary coils, an inductive coupling module is taken as a modulator-demodulator, and a half-duplex communication mode is established by a data-acquiring control satellite communicator in a broadcast mode through various sensors under the water, so that the real-time collection for underwater data is realized. Meanwhile, a mature satellite communication system is selected, a dial-up service supplied by the satellite communication system is utilized to establish a real-time, large-data-volume and stable communication link between a deep-sea buoy and a user data center, and the real-time transmission for deep-sea observed data is realized.

The invention discloses a mobile terminal. The mobile terminal comprises that a first modulator-demodulator is used for obtaining the information of a first user identification card and communicating with a first 4G (the 4th Generation Mobile Communication Technology) network based on the obtained information of the first user identification card so as to carry out voice businesses and data businesses; a second modulator-demodulator is used for obtaining the information of a second user identification card and communicating with a second 4G network based on the obtained information of the second user identification card so as to carry out voice businesses and data businesses; a second application processor is used for setting a second logic port; a first application processor is used for setting and configuring a first logic port corresponding to the first logic port so as to build a connection with the second application processor; and the second application processor is also used for forwarding the data and/or control instructions received through the second logic port to the second modulator-demodulator. The invention also discloses a communication method. According to the mobile terminal and the communication method, normal control instruction and data interaction between two application processors can be realized.

The invention discloses an intelligent housing system and a control method. The intelligent housing system is mainly composed of a gateway server, a client, a modulator-demodulator, a wireless router, a wireless coordinator and at least one wireless node, wherein the wireless router is connected with the Internet through the modulator-demodulator; the client is connected with the wireless router, and the wireless router is connected with the gateway server through a network cable and/or a mobile Internet; the gateway server is connected with the wireless coordinator through a serial port; the wireless coordinator is wirelessly connected with all the wireless nodes. The intelligent housing system disclosed by the invention has the characteristics of being convenient to install and maintain, low in cost, capable of realizing dynamic management for a housing control node, convenient to operate the client, high in system safety, stable, efficient, energy-saving and environment-friendly, and the like.

Disclosed is a method for configuring a pilot frequency in a wireless communication system, comprising: on the basis of at least one item among a current wireless channel characteristic parameter, device capability information of a correspondent node, and system requirement information, configuring in real-time a pilot frequency for different transmissions during a transmission process; and transmitting the configuration result to the correspondent node. Also disclosed is a corresponding device for configuring the pilot frequency. The present invention allows for configuration in real-time of the pilot frequency. This facilitates improved transmission reliability and guaranteed communication quality, and reduces pilot frequency overhead, and at the same time, is applicable in additional number of channel environments and application scenarios.

A method for signal transmission of a relay, includes estimating a first modulation/demodulation channel between a transmitter and the relay and a second modulation/demodulation channel between the relay and a receiver, and an interference channel of the relay, receiving a radio frequency signal from a transmitter, generating a transformation vector using the channel estimate in order to reduce self-interference of the relay under a predetermined level, converting the radio frequency signal using the transformation vector, and transmitting the converted radio frequency signal to the receiver.

The invention provides a joint LDPC encoding recursive MSK modulation and demodulation system, which comprises a transmitting end and a receiving end. The transmitting end comprises an LDPC external encoder and a recursive MSK modulator, and the receiving end comprises a quadrature down conversion and low-pass filter, a coarse carrier frequency offset estimation module, a buffer, a demodulation selector, an MSK differential demodulator, an N frame synchronization head-related detector, an MSK coherent demodulator, a carrier and timing synchronization processing module, a parallel/series conversion module and an LDPC decoder. The invention completely eliminates the performance loss caused by MSK differential encoding by fully integrating the recursive MSK differential encoding part into LDPC codes, fully utilizes the characteristic that the recursive MSK can carry out the differential demodulation, rapidly realizes the detection of frame synchronization head sequence of the LDPC codes under the premise of having no need of precise carrier synchronization, further switches to the MSK coherent demodulation, carries out synchronization and LDPC decoding and realizes the functions of rapid demodulation and decoding.

The invention discloses a modulation and demodulation circuit of fiber option gyroscope (FOG) open-loop signals. The circuit adopts a monolithic LVDT integrated circuit (IC) for modulating and demodulating an FOG open-loop signal, generating a sinusoidal signal, synchronously detecting and dividing one odd harmonic amplitude and one even harmonic amplitude and acquiring the tangent value of a mobile signal phase by low-pass filtration. The invention uses the monolithic LVDT IC to realize the four functions, i.e., sinusoidal signal generation of a drive phase modulator, synchronous detection, the elimination of light-source light-intensity fluctuation influence and low-pass filtration and greatly simplify a signal-processing circuit; the monolithic LVDT IC outputs the tangent value of a mobile signal phase so that when the phase increases and trends to pi/2, the tangent value bends upwards, does not trend to saturation and reduces the error of a complementary tangent operation; and a division operation is internally realized by the monolithic LVDT IC so that a digital signal processor at a high price can be replaced by a monolithic computer at a low price for non-linear corrosion.

The invention discloses an intelligent audio key device connected to a wired earphone interface of a mobile terminal and also discloses a method for utilizing the device to realize the data communication between the device and the mobile terminal. The device comprises an earphone interface module, a data modulation-demodulation module and a safety processing module. The device is connected to a mobile terminal device through wired earphones, thereby realizing the security functions such as digital certificate management, identity authentication, data encryption and decryption, electronic signature, and the like. The device can be widely applied to the mobile terminals, such as a mobile phone with the wired earphone interface, a flat computer, and the like.

The invention discloses an underwater acoustic anti-Doppler multicarrier modulation and demodulation method based on linear frequency modulation. The method comprises the following steps: step one, transmitting terminal multicarrier modulation is performed; step two, Doppler frequency shift factor estimation is performed; and step three, receiving terminal demodulation is performed. The invention also discloses a modulation and demodulation device of the underwater acoustic anti-Doppler multicarrier modulation and demodulation method based on linear frequency modulation. The device comprises a transmitting device and a receiving device which are interconnected. The method has advantages of being high in anti-Doppler capability, wide in applicability, diverse in realization method, low in cost, easy to realize, high in efficiency, etc.