150 results about "Channel modulation" patented technology

Methods and apparatus for optimizing wireless communications channels by employing multi-channel modulation techniques in wireless communication systems is disclosed. The wireless communications channel may comprise tones, and data may be allocated differently among the different tones according to the channel characterization measurements. In one embodiment, a method may include: transmitting data over a wireless channel using a first station (e.g., an access point), receiving the data using a second station, performing calculations on the received data, and allocating subsequent data transmissions among the tones according to the calculations. Other embodiments may utilize superfluous data transmissions-for example, data coming from the access point that is intended for other stations-in order to calculate channel characterization. Preferably, any portion of the transmitted data (e.g., preamble, header, data, etc.) may be used to calculate channel characterization.

A stereoscopic imaging apparatus (200) has an illumination source (110) providing polarized illumination beams and at least one uniformizing element (22) for uniformizing first and second illumination beams. A left channel modulation apparatus (220l) modulates the first polarized illumination beam to provide the left eye portion of the stereoscopic image and a right channel modulation apparatus (220r) modulates the second polarized illumination beam to provide the right eye portion. Each channel modulation apparatus has a color separator (78) for separating the polarized illumination beam into at least a first component wavelength illumination and a second component wavelength illumination. Each channel modulation apparatus also has at least two component wavelength modulating sections, each component wavelength modulating section being a portion of a monochrome transmissive liquid crystal modulator panel (60) that accepts a corresponding component wavelength illumination and modulates the component wavelength illumination to provide a modulated component wavelength beam.

A highly-efficient, cost-effective technique for multi-channel QAM modulation is described. The technique employs an inverse fast-Fourier transform (IFFT) as a multi-channel modulator. QAM encoding expresses QAM symbols as constellation points in the complex plane such that each QAM symbol represents a specific phase and amplitude of a carrier frequency to which it is applied. In multi-channel systems, the carrier frequencies are generally uniformly spaced at a channel-spacing frequency (6 MHz, for digital cable systems in the United States). The IFFT accepts a set of complex frequency inputs, each representing the complex frequency specification (i.e., phase and amplitude) of a particular frequency. The inputs are all uniformly spaced, so assuming that the IFFT is sampled at a rate to provide the appropriate frequency spacing between its frequency-domain inputs, the IFFT will produce a time domain representation of QAM symbols applied to its various inputs modulated onto carriers with the desired channel separation. Since the channel spacing and the symbol rate are different due to excess channel bandwidth, interpolation is used to rectify the difference. An efficient scheme for combining this interpolation with baseband filtering and anti-imaging filtering is described.

The invention discloses a data transmission method for supporting sub-channel modulation coding, which is used in a wireless local area network. The method comprises the following steps of: acquiring sub-channel modulation coding information which contains spatial stream information, sub-channel modulation mode of each spatial stream and coding rate through a first site; packing the sub-channel modulation coding information by adopting a physical layer data unit frame of a predetermined format; and sending a physical layer data unit of a predetermined format to a second site through the first site to demodulate the physical layer data unit frame so as to obtain received data. The invention also provides a corresponding wireless local area network system. As the modulation mode is selected according to the information condition of each sub-channel, the invention improves the data transmission efficiency, supports adaptive modulation coding on the sub-channel consisting of sub-carrier packets, effectively overcomes the frequency selectivity in the system, improves the performance of the system, and is backward compatible with the existing system.

A multi-channel radio frequency generator for high-frequency thermal treatment is used in combination with a plurality of electrodes. The multi-channel radio frequency generator includes an oscillator for producing a high-frequency, a waveform modulator part for modulating an waveform of the high-frequency generated by the oscillator, first to third amplifying channels for amplifying the high-frequency outputted from the waveform modulator part to have a root mean square output of 30-200 Watts and then supplying the root mean square output to the electrodes, a channel selection part for allowing a user to select one or more of the first to third amplifying channels, a key part for enabling the user to set a voltage, a current and an impedance for the first to third amplifying channels, and a microcontroller unit for controlling a power, a time and a phase of the high-frequency outputted from each of the first to third amplifying channels.

A method for receiving -transmitting ground mobile multimedia broadcast of compatible DAB includes receiving service data of multimedia broadcast, carrying out source and channel coding on service data, embedding coded data in main service channel MSC, identifying sub-channel information and carrying out channel coding on data in FIC channel, carrying out channel modulation and OFDM modulation as well as radio frequency modulation on data in FIC and MSC channels then sending modulated data out.

Wideband, direct-to-RF multi channel QAM modulation is described whereby IFFT processing is employed to modulate a plurality of encoded symbol streams in parallel onto a like plurality of uniformly spaced carriers. A high-frequency master clock and high-performance, high-frequency D / A converters are employed. The IFFT modulation process yields a multi-channel multiplex at an intermediate “baseband” frequency. The multi-channel multiplex is then synchronously converted to analog form and synchronously frequency shifted upward by one-half the master clock frequency using a quadrature doubly-balanced mixing scheme. The resultant multi-channel encoded multiplex occupies a frequency band centered around one half the master clock frequency. Multi-rate techniques can be employed to yield high-speed digital processing from digital logic incapable of operating directly at the master clock frequency.

The invention discloses a capturing and tracking system based on a relay terminal and an automatic target tracking method. The system comprises a Ka relay antenna, a filter module, a low noise amplifier module, a single-channel modulation module, a Ka / C frequency conversion module, a capturing and tracking module and a servo control module. Due to the adoption of the automatic target tracking method, a relay satellite beacon antenna forward single-beacon signal can be captured and tracked by a low-track satellite relay terminal. Compared with the technology that TM01 is adopted as a difference mode and an analog processing method is adopted in the prior relay satellite technology, the automatic target tracking method has the advantages that a TE11 sum mode and TE21 difference mode higher-order mode error generation method meets the requirements that any polarization signal can be tracked by the relay terminal and azimuth and pitching error cross coupling is small; due to the utilization of a method for capturing and tracking a beacon signal large in frequency offset and low in signal to noise ratio, large-frequency-offset frequency compensation and dynamic tracking are achieved, and system sensitivity is high; due to the utilization of a digital azimuth error delta A and pitching error delta E extraction, separation and filter method, requirements for high-precision target orientation and tracking are met.

The invention relates to the wireless communication field and discloses a communication method and a device thereof in a multi-input and multi-output system; the utilization ratio of spectrum can be improved under the same total power by centrally distributing undistributed power to sub channels modulation coding orders of which can be improved most easily. By the optimization for a plurality of times, the undistributed power can be used fully; when the undistributed power can not improve the modulation coding orders of any sub channels, the undistributed power can be evenly distributed to the sub channel of each transmission data so as to further improve the error performance of the system. A codebook is used for feedbacking power distribution vector, which can effectively reduce the feedback amount of information; the use of two codebooks are used at the same time, thus respectively feedbacking the power distribution vector and pre-code matrix and improving the transmission performance of the system under the condition of limited feedback.

A stereoscopic imaging apparatus (200) has an illumination source (110) providing polarized illumination beams and at least one uniformizing element (22) for uniformizing first and second illumination beams. A left channel modulation apparatus (220l) modulates the first polarized illumination beam to provide the left eye portion of the stereoscopic image and a right channel modulation apparatus (220r) modulates the second polarized illumination beam to provide the right eye portion. Each channel modulation apparatus has a color separator (78) for separating the polarized illumination beam into at least a first component wavelength illumination and a second component wavelength illumination. Each channel modulation apparatus also has at least two component wavelength modulating sections, each component wavelength modulating section being a portion of a monochrome transmissive liquid crystal modulator panel (60) that accepts a corresponding component wavelength illumination and modulates the component wavelength illumination to provide a modulated component wavelength beam.

Characters of the voltage follower are that a feedback loop is composed of one PMOS input tube M1, first current source I2, two NMOS tubes M2 and M3, a current sink I1, and second current source I3. The feedback loop reduces output resistance, and increases output amplitude of the voltage follower remarkably. At same time, drain electrode of the input tube of the voltage follower becomes a node with low impedance so as to make fluctuation of drain voltage of the input tube become smaller as well as reduce effect of channel modulation of input tube. Advantages are: small output resistance, large output amplitude, high linearity, and suitable to be operated at low voltage.

A unique new modulation scheme is employed to add the auxiliary channel. This is realized, in one embodiment of the invention, in a quadrature phase shift keying (QPSK) transmission system, by utilizing a “large” phase variation component to modulate the primary channel and a relatively “small” amplitude variation component to modulate the new auxiliary channel. There are a number of known transmission schemes in which applicant's unique auxiliary channel modulation scheme can be used to realize his unique invention. One example for such a transmission system an enhanced QPSK transmission system. The primary channel, or the original transmission system, uses PQSK where every two bits of data is mapped to a symbol I+j Q, where j is the imaginary unity. In the enhanced QPSK transmission system, every two bits from the primary channel data, and every two bits from the auxiliary channel data are mapped to the symbol I(1+ / −a)+j Q(1+ / −a). The mapping between the two bits from the primary channel data and I, Q is the same as in the prior QPSK system. However, in the enhanced QPSK system, the auxiliary channel data is carried in the system by the variation + / −a. The sign “+ / −” depends on the polarity of the auxiliary channel bits. The amplitude “a” can be adjusted to adjust the data rate of the auxiliary channel and the interference to the primary channel.

The inventions relate to compositions and articles of manufacture comprising connexin modulators, pannexin modulators, gap junction modulators, hemichannel modulators, and pannexin channel modulators and their use, alone or in combination, in treating ocular and other disorders.

A concatenated coded modulation communication system and method combines Trellis Coded Modulation with non-Gray code constellation mapping, interleaving, and non-binary Low Density Parity Check coded channel modulation with Gray code constellation mapping to improve error performance.

The invention discloses a method for obtaining a sub-information channel modulation code, comprising the following steps: sending a request message requiring for providing sub-information modulation code information to an opposite terminal station, wherein the request message contains a control field in a preset format, and the control field comprises a sub-information channel modulation code information request, a training request, an MCS request or an antenna selection indication, an MCS feedback and an antenna selection order / data; and receiving a response message from the opposite terminal station, wherein the response message comprises a data frame structure packaged with sub-information channel modulation code information in the preset format, the sub-information channel modulation code information data frame is carried with spatial stream information, sub-information channel modulation mode and encoding speed of each spatial stream, and subcarrier grouping information. In the invention, frame structure and frame interactive sequence are designed reasonably, and adaptive modulation encoding on each sub-information channel which is composed of subcarrier groupings is supported, thereby effectively overcoming frequency selectivity of a system, improving system performance, and securing backward compatibility with current system to the greatest extent.

A modulator, and demodulator, apparatus and method for use in a multiple sub-channel communication system is taught. A commutator is employed for fractionally sampling, or distributing, signals from, or to, a multiple channel polyphase filter. The filter is coupled with a discrete Fourier transform, or its inverse, such that the relationship between the base-band sampling rate of a plurality of sub-channel signals, the frequency spacing of the sub-channel signals, and the sampling rate of a composite signal can be related by any rational number, thereby freeing designers to optimize system design respecting channel spacing, bandwidth, and signaling rates. The advantages of the present invention are realized by adjusting the interpolation and decimation rates of the filter, and by adjusting the resolution and decimation rates of the transform.

Systems and methods for producing multi-dimensional parametric audio are provided. The systems and methods can be configured to determine a desired spatial position of an audio component relative to a predetermined listening position; process the audio component for a predetermined number of output channels, wherein the step of processing the audio component comprises determining the appropriate phase, delay, and gain values for each output channel so that the audio component is created at the desired apparent spatial position relative to the listening position; encode two or more output channels of the audio component with the determined phase, delay, and gain values for each output channel; and modulate the encoded output channels onto respective ultrasonic carriers for emission via a predetermined number of ultrasonic emitters

The invention provides a band-gap reference voltage source design with high gain and a high rejection ratio. A band-gap reference voltage source circuit is composed of an operational amplifier circuit, a starting and biasing circuit, a rejection ratio increasing circuit and the band-gap reference voltage source circuit. A high-gain operational amplifier is adopted for effectively guaranteeing precision and stability of Delta VBE, and offset is reduced by means of multistage amplification; the starting and biasing circuit provides starting voltage and bias for the other circuits, and is closed after the other circuits are started; the rejection ratio increasing circuit increases rejection of the whole circuit on power supply change in a current feedback mode, a locally supplied power supply VDDL is generated, and anti-interference performance of the circuit is enhanced; the band-gap reference voltage source circuit increases the power supply rejection ratio of output voltage by adoption of a current mirror of a self-bias cascade structure, and coordinates with an external circuit to generate reference voltage with stable performance and zero-temperature coefficient. Due to the adoption of the high-gain two-stage operational amplifier, a voltage source isolation technique, an RC compensation network and the current mirror in the self-bias cascade structure, the circuit has low offset voltage, high phase margin, high gain and high rejection ratio, and impact caused by MOS (metal oxide semiconductor) device channel modulation effect is reduced.

The invention discloses methods for extracting and modeling Chinese speech emotion in combination with glottis excitation and sound channel modulation information. The method for extracting Chinese glottis excitation information comprises the following steps of: setting an electric glottogram emotion speech database standard; collecting glottogram emotion speech data; and objectively evaluating glottogram emotion speech, i.e., evaluating the glottogram emotion speech with at least ten evaluators. The method for modeling Chinese emotion in combination with glottis excitation and sound channel modulation information comprises the following steps of: firstly, extracting glottis excitation information according to a glottogram; secondly, extracting sound channel modulation information in a speech signal according to the relation between the glottogram and the speech signal; and lastly, selecting an appropriate emotion characteristic for each emotion by using the Fisher rates of all standby characteristics, and training a one-to-many support vector machine model. In the invention, the glottis excitation information is extracted through a glottogram signal, and the glottis excitation information is separated from the sound channel modulation information in the speech signal, so that the emotion information in the speech can be reflected more accurately.

The present invention relates to a limited innovation rate-based pulse string signal undersampling system and method, and relates to the signal processing technology field. According to the present invention, by utilizing the parameterized characteristics of a pulse string signal, and by the four-channel modulation, amplification, low-pass filtering and undersampling processing, the discretely distributed Fourier coefficients in the frequency spectrum of the pulse string signal are obtained, and then the unknown amplitude and time delay parameters are reconstructed by few obtained Fourier coefficients. According to the present invention, the time delay reconstruction precision is very high, and the amplitude estimation only has a very small error.

The invention discloses a testing system for radio frequency consistency of a satellite mobile communication terminal and a testing method of the testing system. The system comprises a logic channel information generator, a frequency correction channel modulation module, another service and control channel modulation module, a channel multiplexing module, a radio frequency up-conversion module, a satellite-to-ground channel simulator, a duplexer, an attenuator, a radio frequency down-conversion module, a channel demultiplexing module, a terminal random access channel demodulation module, a terminal service data channel information acquisition module and a radio frequency consistency testing module. The testing system constructs a satellite-to-ground channel environment by matching the satellite-to-ground channel simulator with the radio frequency up-conversion module, the radio frequency down-conversion module and the attenuator, and simulates a ground station to test the satellite mobile communication terminal. The testing system tests the radio frequency consistency of the satellite mobile communication terminal, is simple in structure and easy to realize, and can lower the testing cost, thereby promoting industrial development of satellite mobile communication.

A bit / power loading method in an adaptive modulation-based multicarrier communication system computes ratios of modulation mode values to transmission power values sub-channel-by-sub-channel, selects a combination of sub-channels in which a sum of the ratios is maximized for a total number of bits to be simultaneously transmitted, and transmits signals in modulation modes corresponding to ratios of modulation mode values to transmission power values associated with the selected sub-channels. Because the bit / power loading method selects a combination of sub-channel modulation modes with the minimum total transmission power for a given number of bits on the basis of transmission power in each sub-channel modulation mode, the bits can be transmitted at the minimum transmission power in a given environment.

The invention discloses a field effect transistor gas sensor and an array preparation method thereof. The field effect transistor (FET) gas sensor is a gate-sensitive FET gas sensor with a gate electrode modified by quantum dots, and a gate-sensitive electrode layer (5) of the FET gas sensor is of a two-layer composite structure or of a single-layer structure made of a composite material. The two-layer composite structure comprises a metal film layer and a quantum dot layer deposited on the surface of the metal film layer. The single-layer structure made of a composite material is specificallya single-layer structure made of a composite material formed by combining quantum dots and a metal or metalloid material. According to the invention, improvement is made on the internal composition and structure of the gate-sensitive FET, the corresponding preparation method and the like, quantum dots are used as a gate electrode and a gas sensitive layer at the same time, and the bias voltage ofthe gate electrode and the channel modulation effect are regulated and controlled by utilizing the adsorption characteristic of a quantum dot gate-sensitive electrode to different gases. A room-temperature gas sensor with high sensitivity, low power consumption and high selectivity can be obtained, and low-concentration target gases (such as H2) can be detected.

The invention discloses a indication method for high speed downlink shared physical channel modulation mode, relates to indication technology of channel modulation mode, and aims to solve the current problem that HSDPA system can not display 64QAM modulation mode. The adopted technical solution comprises: expanding HS-PDSCH code track distribution indication signaling in shared control channel HS-SCCH, and indicating HS-PDSCH modulation mode together with the modulation mode signaling. The invention further discloses a determining method for high speed downlink shared physical channel modulation mode, and a high speed downlink shared physical channel modulation mode indicating and determining apparatus for realizing the above method. The invention designs out a method for indicating three downlink modulation mode and code track distribution, without changing the length of each signaling of HS-SCCH in existing standard, and minimizes the complexity of system to determine adjustment mode through simple mapping relation.

The invention discloses wireless transmission environment-oriented IEEE1588 protocol optimization system and an IEEE1588 protocol optimization method thereof. The system comprises a master clock node, a channel modulation / demodulation module, a transmitting antenna module, a receiving antenna module, a power adjustment module, a synchronization processing module, a signal processing module and a slave clock node, wherein the master clock node, the channel modulation / demodulation module, the transmitting antenna module, the receiving antenna module, the power adjustment module, the synchronization processing module, the signal processing module and the slave clock node are successively connected. According to the wireless transmission environment-oriented IEEE1588 protocol optimization system and the IEEE1588 protocol optimization method provided by the invention, application limitation of an existing IEEE1588 time synchronization protocol in a wireless environment is improved and the application range is extended, thereby improving precision of time synchronization in the wireless network.

The invention discloses an implementation method and a system for a super-high speed multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) wireless LAN, and belongs to the wireless communication technical field. By the implementation method and in the system, a transmitting site can simultaneously transmit one or a plurality of independent data sub-streams through a transmitting antenna set and can adopt different signal modulation modes for the OFDM sub-channels of the independent data sub-steams. In a certain space-time coding mode and error correcting code mode, the signal modulation modes adopted for the OFDM sub-channels are decided by the receiving site according to the signal-to-noise ratios before the modulation at the sub-channels, before the independent data sub-steams are space-time coded. The information about the signal modulation modes of the independent sub-streams at the OFDM sub-channels (sub-channel-modulation mode information) is transmitted from the receiving site to the transmitting site in a request-response manner or an active transmission manner.

A modulated optical system with anti-clipping reduces or corrects clipping that might occur in the laser as a result of negative spikes or peaks in a multichannel RF signal. The system generally detects an envelope of the RF signal to generate an anti-clipping signal that follows at least a portion of the envelope and prevents one or more negative peaks from causing clipping by adjusting a bias current in response to the anti-clipping signal. The system may also reduce cross modulation by clamping the anti-clipping signal at an anti-clipping limit during lower power periods of the RF signal.