377results about "Pulse position modulation" patented technology

A respiratory mask assembly for use in the delivery of non-invasive positive airway pressure to a user. The assembly includes a rigid shell having a channel portion defined by an inner wall, an outer wall and a channel floor, a face-contacting cushion acting to space the shell away from the user's face and a sealing tab extending from the cushion to engage a portion of the shell to provide a continuous airtight seal between the cushion and the shell. A retaining ring within the mask assembly is configured to secure the cushion to the shell. The retaining ring has a first portion including at least one clip configured to pass through at least one slot portion such that an underside surface of the at least one clip engages a section of the shell when the retaining ring is positioned within the channel.

Embedded piezoelectric sensors in large civil structures for structural health monitoring applications require data communication capabilities to effectively transmit information regarding the structure's integrity between sensor nodes and to the central processing unit. Conventional communication modalities include electromagnetic waves or acoustical waves. While guided elastic waves can propagate over long distances on solid structures, their multi-modal and dispersive characteristics make it difficult to interpret the channel responses and to transfer useful information along pipes. Time reversal is an adaptive transmission method that can improve the spatiotemporal wave focusing. The present disclosure presents the basic principles of a time reversal based pulse position modulation (TR-PPM) method and demonstrates TR-PPM data communication by simulation. The present disclosure also experimentally demonstrates data communication with TR-PPM on pipes. Simulated and experimental results demonstrate that TR-PPM for data communications can be achieved successfully using guided elastic waves.

This invention extends the range of optical data of mobile device by trading speed for distance as well as integrating a plurality of pulses over time to define a single bit of information. The present invention uses a number of integrated pulses to represent a single bit instead of utilizing a one to one correspondence between pulses and bits. The present invention executes a range extender application which executes on the mobile device without any hardware modification to the mobile device. The range extender application causes the optical transmitter to “stutter” or repetitively emanate the identical pulse representing a bit of information. Sufficient photons are thereby gathered at a receiver to reach a predetermined threshold. A tradeoff of the data transmission frequency in this invention is that a signal intensity drops by a factor of 100 when distance increases by a factor of 10 yielding a distance / intensity ratio of {fraction (1 / 10)}.

[Problems] To realize a reliable and stable transfer of digital data that does not require a reference clock and a handshake operation. [Means for Solving the Problem] The present invention provides a digital data transfer method for alternately and periodically transferring first information and second information respectively in a first period and in a second period, wherein: an amount of information of the first information per unit time in the first period is greater than an amount of information of the second information per unit time in the second period; and the second information in the first period is transferred as pulse-width-modulated serial data.

[Problems] To realize a reliable and stable transfer of digital data that does not require a reference clock and a handshake operation.[Means for Solving the Problem] The present invention provides a digital data transfer method for alternately and periodically transferring first information and second information respectively in a first period and in a second period, wherein: an amount of information of the first information per unit time in the first period is greater than an amount of information of the second information per unit time in the second period; and the second information in the first period is transferred as pulse-width-modulated serial data.

An ultra-wideband pulse modulation system and method is provided. One method of the present invention includes transforming data into a ternary data set with data being represented with states of zero, positive one and negative one. The modulation and pulse transmission method of the present invention enables the simultaneous coexistence of the ultra-wideband pulses with conventional carrier-wave signals. The present invention may be used in wireless and wired communication networks such as hybrid fiber-coax networks. This Abstract is provided for the sole purpose of complying with the Abstract requirement rules that allow a reader to quickly ascertain the subject matter of the disclosure contained herein. This Abstract is submitted with the explicit understanding that it will not be used to interpret or to limit the scope or the meaning of the claims.

A system, method and computer program product for positioning pulses, including positioning pulses within a specified time layout according to one or more codes to produce a pulse train having one or more predefined spectral characteristics where a difference in time position between adjacent pulses positioned to produce a spectral characteristic differs from another difference in time position between other adjacent pulses positioned to produce the spectral characteristic. The present invention may include shaping a code spectrum according to a spectral template in order to preserve a pre-defined code characteristic. A pre-defined code characteristic can include desirable correlation, or spectral properties. A transmitter incorporating the present invention can avoid transmitting at a particular frequency. Similarly, a receiver can avoid interference with a signal transmitting at a particular frequency. A radar system, can avoid a radar jammer attempting to jam a particular frequency.

An apparatus and method for amplifying a Transmit (Tx) signal according to an Envelope Tacking (ET) scheme in a wireless communication system are provided. A transmitting end apparatus includes an envelope gain controller for controlling a gain of a digital baseband Tx signal in accordance with power control, a detector for detecting an envelope signal from the digital baseband Tx signal whose gain is controlled, and for shaping on the envelope signal, a first Digital to Analog Converter (DAC) for converting the shaped envelope signal into an analog signal, and an envelope modulator for generating a drain bias of a power amplifier that amplifies a Radio Frequency (RF) Tx signal by using the analog envelope signal. Accordingly, a digital-based ET scheme is implemented, and by using a plurality of shaping tables, efficiency of the ET scheme can be maximized in a transmitting end that uses power control.

A coding method specifies pulse positioning over time according to a time layout about a time reference where a pulse can be placed at any location within the time layout. The method generates time-hopping codes having predefined properties, and a coded pulse train based on the time-hopping codes and the time layout. The time reference may be fixed or non-fixed and can be a time position of a preceding or a succeeding pulse. In addition, the predefined properties can be autocorrelation, cross-correlation, or spectral properties.

A signal filtering system and method that may be used in conjunction with a repeater or an input stage of a base-station. The system may include an analog to digital converter adapted to sample a received signal and to produce a data stream corresponding to the received signal in the time domain, a filtering block having one or more digital filter elements, wherein each of said one or more filter elements is adapted to filter one or more sets of frequency bands associated with one or more communication channel, and a controller adapted to configure said one or more digital filter elements based on parameters stored on a database and / or based on parameters received via a modem.

A method of space time coding for UWB transmission system including a plurality of radiative elements, the method coding a block of information symbols S=(σ1, σ2, . . . , σP) belonging to a M-PPM-M′-PAM modulation alphabet, as a sequence of vectors obtained from elements of the matrix:C=(σ1σ2…σPΩσPσ1⋱⋮⋮⋱⋱σ2Ωσ2…ΩσPσ1)a row of the matrix corresponding to a use of the transmission channel and a column of the matrix corresponding to a radiative element, the matrix C being defined to within a permutation of its rows and / or its columns and Ω being defined as the combination of a permutation (ω) of the modulation positions of the M-PPM alphabet and a symmetry operation (π) of the M′-PAM modulation alphabet for one of the modulation positions (m±).

A coding method, specifies temporal and / or non-temporal pulse characteristics, where pulse characteristic values are relative to one or more non-fixed reference characteristic values within at least one delta value range or discrete delta value layout. The method allocates allowable and non-allowable regions relative to the one ore more non-fixed references. The method applies a delta code relative to the allowable and non-allowable regions. The allowable and non-allowable regions are relative to one or more definable characteristic values within a characteristic value layout. The one or more definable characteristic values are relative to one or more characteristic value references. In addition, the one or more characteristic value references can be a characteristic value of a given pulse such as a preceding pulse or a succeeding pulse.

A hybrid wireless and wired system distributes precise timing and synchronization information among the nodes over a wired interconnect structure while data is transmitted wirelessly using ultra-wideband radio over short distances. The timing information communicated over the wired interconnect structure is used to establish a baseline timing reference for the wireless transmitters, receivers and transceivers on the nodes of the communication network. Using a common timing reference, a mesochronous communication system is established for chip-to-chip wireless data transmission.

A template pulse generating circuit that generates a template pulse used for detection of a received pulse in pulse communication includes an output mode switching circuit for switching an output mode in accordance with a supplied control signal between a continuous output mode that continuously outputs the template pulses and an intermittent output mode that intermittently outputs the template pulses so that the template pulse is generated in either one of the continuous output mode and the intermittent output mode.

A signal filtering system and method that may be used in conjunction with a repeater or an input stage of a base-station. The system may include an analog to digital converter adapted to sample a received signal and to produce a data stream corresponding to the received signal in the time domain, a filtering block having one or more digital filter elements, wherein each of said one or more filter elements is adapted to filter one or more sets of frequency bands associated with one or more communication channel, and a controller adapted to configure said one or more digital filter elements based on parameters stored on a database and / or based on parameters received via a modem.

A system and a method for encoding and decoding ultra-wideband information are provided. An ultra-wideband transmission is encoded by positioning bipolar pulse pairs. The bipolar pulse pairs assist in detecting errors in the ultra-wideband transmission, before the entire transmission has been received. The transmission is analyzed for errors and an error rate is calculated. The calculated error rate is compared to one or more predefined acceptable error rate levels to determine whether the calculated error rate of the transmission is within at least one of the predefined acceptable error rate levels.

A method for processing a signal propagated through a nonlinear channel is disclosed. The method comprises modeling the channel characteristics to produce a linearized channel model, wherein the linearized channel model has a linearized transfer function that includes a plurality of first order polynomials and nonlinear operators. The method further comprises deriving an inverse linearized channel model from the linearized channel model and filtering the signal using the inverse linearized channel model.

An electrosurgical system is disclosed. The electrosurgical system includes an electrosurgical instrument configured to generate a first and second data streams and a transmission circuit configured to convert the first and second data streams into a pulsed transmission signal. The first signal property of the transmission signal is representative of the first data stream and the second signal property of the transmission signal is representative of the second data stream. The transmission circuit is further configured to process the transmission signal to decode the first signal property into the first data stream and the second signal property into the second data stream.

In a modulation system, in order to provide a two-level signal with a desired modulation which is suited to be amplified by a switching mode power amplifier, the modulation system may include a first constant envelope modulator modulating a signal according to a first control signal, a second constant envelope modulator modulating a signal according to a second control signal, and a combining portion combining the output signal of the first and said second constant envelope modulator to a single, two-level pulse-width-modulated signal. The information which is to be represented by the modulation of the single, two-level pulse-width-modulated signal is coded in the first and the second control signals. The invention relates equally to a corresponding method for generating a modulated signal.

According to one embodiment of the invention, an integrated circuit comprises an encoding module, a modulation module and a spectral shaped module. The encoding module includes an interleaver that adapted to operate in a plurality of modes including a first mode, a second mod and a third mode. The interleaver performs repetitive encoding when placed in the second mode and even greater repetitive encoding when placed in the third mode.

Methods and systems for generating a variable spacing pulse position modulated (VSPPM) signal for transmission across an ultra-wideband communications channel. The variable pulse position modulated spread spectrum signal is created by encoding every M input data bits from an input data stream into a symbol consisting of Nc chips. Each chip is divided into 2M sub-chips and each sub-chip is further divided into Np time slots. A pulse is transmitted for each chip in the symbol. During each chip period, the pulse is placed in the sub-chip corresponding to the binary M-tuple (or symbol) value. A time hopping code sequence consisting of Nc elements with a one-to-one chip association is then applied to each symbol so that the position of each pulse is shifted to the appropriate time slot that corresponds to the time hopping code value.

Circuits and methods of dynamic modulation are disclosed. A dynamic modulator is used to reduce measurable conducted and / or radiated electromagnetic interference (EMI). The dynamic modulator is configured to generate either a set of optimal frequency modulation depths or discrete frequencies or both, and dynamically selects them to use over a series of programmable time durations (dwell time). Together with the utilization of Peak, Average or Quasi-Peak (QP) method of measurement, the dynamic modulator can reduce the spectral amplitude of EMI components, in particular the lower harmonics, to effectively pass regulatory requirements. In alternative embodiments, the dynamic modulator is used in a closed loop system to continuously adjust the frequency and the duty cycle of a PWM signal to reduce conducted and / or radiated EMI.

The present invention provides for a methods, system, and apparatus relating to data transmission. One method of the present invention includes representing data using at least one ultra wideband pulse, sending the at least one ultra wideband pulse over an electrically conductive guided media, and recovering the data from the at least one ultra wideband pulse. The present invention can be used in conjunction with telephony applications, cable TV applications, power line applications, fiber optic applications, and data bus applications.

Methods, systems and devices are described for a direct-sequence spread-spectrum communication scheme that increases the number of users by utilizing a plurality of closely spaced orthogonal carriers that produce overlapping spectra. A method includes overlapping a plurality of direct-sequence spread-spectrum signals using carrier frequencies that are orthogonally spaced relative to a bit rate. The methods, systems and devices provide advantages because they can accommodate an increase in the number of normalized users and can optimize the loading of users across multiple frequency channels.

A method of communicating information from first and second transponders (or multiple transponders) to a central monitoring device, and a communications apparatus, are disclosed. The method includes receiving a starting indication at the transponders, determining start times for the transponders in response to that indication, and transmitting first and second sets of bursts from the first and second transponders, respectively. The bursts of the first set occur at at least some of a first set of potential transmission times within an interrogation period, and the bursts of the second set occur at at least some of a second set of potential transmission times during that period. Each of the potential transmission times of the burst sets are respectively determined in relation to the start times of the respective transponders. The potential transmission times of the respective burst sets are separated from one another by one of a bit-cell period and a multiple thereof.

A DTV transmitter includes an encapsulation unit which encapsulates enhanced data having an internet protocol (IP) format into a plurality of addressable sections. The encapsulation unit inserts burst time information into each addressable section. The DTV transmitter further includes a first multiplexer multiplexing the encapsulated enhanced data with program and system information, a pre-processor pre-processing the multiplexed enhanced data, a data formatter generating enhanced data packets including the pre-processed data and inserting the known data into the enhanced data packets, and a second multiplexer generating one or more bursts of data by multiplexing the enhanced data packets.

A parallel channel timing recovery circuit. The parallel timing recovery circuit comprises multiple prefilters receiving parallel channel outputs and providing prefilter outputs. Multiple sampling filters receive the prefilter outputs and provide multiple discrete time signal samples. A self-timing circuit has multiple inputs receiving the multiple discrete time signal samples. The self-timing circuit provides a sampling control output to the sampling filters. The sampling control output is based on a composite of the multiple discrete time signal samples. Each of the sampling filters generates a discrete time signal sample based on the sampling control output and the prefilter outputs.

A 1 / n-rate decision feedback equalizer (DFE) and method include a plurality of branches. Each branch includes a summer circuit configured to add a feedback signal to a received input, and a latch configured to receive an output of the summer circuit in accordance with a clock signal. A feedback circuit includes a multiplexer configured to receive as input, an output of each branch, the multiplexer having a clocked select input and configured to multiplex the output of each branch to assemble a full rate bit sequence, and a filter configured to provide cancellation of intersymbol interference (ISI) from the received input to be provided to the summer circuit of each branch.

A system and method for accurately measuring a pulse run length in a high frequency (HF) data signal while utilizing a low analog-to-digital conversion (ADC) sampling rate. Four bits are added to the most significant end of an oscillator's accumulator register so that the oscillator generates a sawtooth clock waveform ranging in phase from zero (0) to 32pi radians. An interpolator detects a first zero-crossing transition of the HF data signal at the leading edge of the pulse run length, and a phase detector measures a first phase increment at that time. The MSBs of the accumulator register is then initialized to place the measured first phase increment in a range between zero (0) and 2pi radians. The accumulator register then accumulates phase increments until the interpolator detects a second zero-crossing transition of the HF data signal at the trailing edge of the pulse run length, and the phase detector measures a second phase increment when the second zero-crossing transition is detected. An accumulated phase difference is calculated by subtracting the initialized first phase increment from the measured second phase increment. The pulse run length is then obtained by dividing the accumulated phase difference by 2pi.

To improve the reliability of channel estimation, data symbols at determined positions of the transmitted data stream are replaced by quasi-pilot symbols. The quasi-pilot symbols carry data modulated onto the carrier with a different modulation scheme than the original symbols. The modulation scheme for the quasi-pilot symbols has a lower amplitude and / or phase ambiguity than the modulation scheme for the original data symbol.