Abstract: A method and a device are proposed for the conversion of a quantized signal into a pulse width modulated signal, wherein dependent on a signal value of the quantized signal in each case a pulse duration of a pulse is determined within a period of the pulse width modulated signal, in which the pulse width modulated signal assumes a first value, while in the remainder of the period it assumes a second value, and wherein a phase position of the pulse is varied within the period of the pulse modulated signal from period to period in such a manner that energy of the pulse width modulated signal is distributed across a broad frequency spectrum. In one case, this takes place by means of parallel switched SD modulators and a vector controller.

Abstract: The pulse train of a signal is modulated by a DPIM modulation involving a discrete random time parameter. A first processing is performed on the signal to deliver a sampled signal. A second processing is performed on the sampled signal, comprising a correlation processing including at least one elementary correlation processing with a correlation mask corresponding to the shape of at least part of a sampled pulse, and delivering second information items. A third processing is performed for detecting the pulses following a first pulse by taking account of the position of the first pulse, on packets of second information items, which are separated by a duration related to the discrete random parameter.

Abstract: The invention relates to a method for determining the position xp of a peak of a pulse in a signal received at a receiver. In order to improve the accuracy of this determination, the method comprises taking samples of said received signal, determining at least three samples, at least one of which has a signal strength exceeding a threshold value, and determining the position xp of the pulse peak based on an interpolation of at least two of the determined samples, which at least two samples are selected based on the signal strengths of the at least three determined samples, and which interpolation includes an evaluation of the signal strength of the at least two samples. The invention relates equally to a device and to a cellular communication system comprising means for realizing this method.

Abstract: A microcontroller having digital to frequency converter and pulse frequency modulator capabilities. The digital to frequency converter (DFC) generates a 50 percent duty cycle square wave signal that may be varied in frequency, wherein the 50 percent duty cycle square wave signal is directly proportional and linear with a count value put into an increment register. The pulse to frequency modulator (PFM) generates pulses having pulse widths of the input clock for each rollover of a counter. The frequency of these pulses is directly proportional and linear with the count value put into the increment register.

Abstract: A ranging and communication multifunction system processable by integrating a ranging function and a communication function is provided. The ranging and communication multifunction system 1 of the present invention includes a transmission unit 2 and a receiving unit 3, and integrates two functions of ranging and communication. The transmission unit 2 includes a transmission circuit 4, a carrier wave modulation device 5, and a transmission antenna 6, and the receiving unit 3 includes a receiving circuit 7, a wave detector 8, a low noise amplifier (LNA) 9, and a receiving antenna 10. The data modulation performed in the transmission circuit 4 uses a PPM system. The receiving circuit 7 provides a ranging circuit 11 and a communication circuit 12 separately, so that the demodulation processing of ranging and communication can be performed in parallel.

Abstract: The present invention concerns channel codes particularly well adapted to transmission in channels in which errors tend to occur in bursts. Moreover, the codes according to one embodiment of the invention using an algebraic geometric curve are easy to decode and have a relatively high minimum distance. The invention also relates to the corresponding encoding and decoding methods, as well as the devices and apparatuses adapted to implement those methods. Application is in particular to mass storage, and to systems of communication by OFDM.

Abstract: 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.

Abstract: A digital automatic gain control circuit is disclosed. The circuit includes a selector, a scaler, a detector, a gain adjustor and a controller. In one exemplary aspect, the selector receives an input signal having two components, namely, the in-phase (I) and quadrature (Q) components, in digital form. The selector then selects a subset of bits from each component based on a control signal provided by the controller. The two subsets are then forwarded to the scaler. The scaler then multiplies the two subsets respectively against a gain value to generate two multiplication results. A portion of each multiplication result is then provided as output by the scaler. The gain value and the subset selection are periodically adjusted in response to the scaler output. The adjustments with respect to the gain value and the subset selection are effectuated collectively by the detector, the gain adjustor and the controller.

Abstract: Described herein are ultra wideband (UWB) receiver systems, and applications thereof. Such a UWB receiver includes a receiver front end and a correlator coupled to the receiver front end. The receiver front end is configured to receive a UWB signal having a plurality of multipath components. The correlator is configured to correlate the UWB signal with a reference signal. The UWB signal includes a plurality of pulses, wherein each pulse has a plurality of multipath components. The reference signal also includes a plurality of multipath components of the pulse. The correlator includes at least one correlator module configured to correlate a plurality of the multipath components of the pulse with the reference signal.

Abstract: A method and apparatus to improve modulation efficiency. A symbol is created in which the relative position of a second pulse is a symbol period encode at least one bit. The symbol is transmitted across a communication channel. The one or more bits modulated by the position of the second pulse are recovered such that high bit rate communication may occur without channel compensation.

Abstract: A system and method is provided for implementing forced frequency “hops” if the time it takes to perform a particular transaction is greater than the time available on a particular carrier frequency. In one embodiment of the present invention, a radio frequency identification (RFID) base station processor (in conjunction with program information stored in a base station memory) is adapted to (i) determine the amount of time available on a particular carrier frequency (e.g., pursuant to Federal Communications Commission (FCC) regulations, European Telecommunications Standardization Institute (ETSI) regulations, etc.), (ii) determine the amount of time it would take to perform a particular transaction, and (iii) force the base station to “hop” to another carrier frequency if the transaction time is longer than the available time. In one embodiment of the present invention, the time it would take to perform a particular transaction is the time it would take to perform the next transaction.

Abstract: A Time-to-Digital Converter (TDC) is constructed using simple digital delay circuits. The design uses a clock compensation scheme to modify and adjust the TDC's operation under integrated circuit fabrication process variations. The TDC design is based on a novel digital processing algorithm that produces one conversion every clock cycle. Therefore, this TDC is the “first” single cycle latency TDC targeted at high speed circuit applications such as (but not limited to) time-based Analog to Digital Converters (ADCs) for direct analog to digital conversion of radio frequency signals in wireless communication systems and high speed signal measurement applications. Due to its hierarchical design approach, the TDC design uses an optimized number of delay circuits and therefore requires very little power consumption and silicon area.

Abstract: The burst oscillation device 20 includes the data generation part 21, the operation part 11, the signal selecting part 40 and the burst generation part 50. The generation part outputs the encoded data encoded based on data for communication. At the signal selecting part 40, the pulse release timing of predetermined repetition period is randomly delayed by the PPM and further delayed randomly by the minimal time by means of the PSK modulation, thereby realizing the decreasing of the peak value of the average power spectral density.

Abstract: A system and method are disclosed for processing a signal propagated through a nonlinear channel. The method includes modeling the channel characteristics to produce a linearized channel model, deriving an inverse linearized channel model from the linearized channel model, and filtering the signal using the inverse linearized channel model.

Abstract: A digital controller for dc-dc switching converters can operate under light load conditions. The controller can be suitable for the use in switch-mode power supplies providing regulated output voltage for handheld devices and other low-power electronics. To create long time intervals, compared to the propagation time of digital logic a DPFM/DPAM can use a ring oscillator with two sets of delay cells and two signals racing around the ring.

Abstract: A system includes a transceiver circuit to transceive at least a first analog signal and a digital signal. The system also includes a controller circuit, coupled to the transceiver circuit, to deliver at least one control signal thereto, the controller circuit including executable instructions defining a data frame for communication of the first analog signal and the digital signal, endpoints of the data frame defined by portions of successive first and second synchronization signals and defining a corresponding frame interval, the data frame including a first data band for transceiving a first data pulse therein. A relative position in time of the first data pulse represents the first analog signal, and a modulation of the frame interval represents the digital signal. The system further includes an analog signal interface circuit, coupled to the transceiver circuit, to provide at least the first analog signal representative of acquired data.

Abstract: In a method and a circuit for timing pulse generation, a frame pulse of a corresponding system is masked when an alarm signal of either a working system or a protection system is received, a monitoring window which indicates an absorbable range of delay time difference between the frame pulses is generated upon an arrival of the frame pulse of the system selected by a switching signal, when the alarm signal of a system not selected is generated upon selection of the switching signal. Alternatively, a request signal for regenerating the monitoring window which indicates an absorbable range of delay time difference between the frame pulses is provided upon an arrival of the frame pulse of the system selected by the switching signal, when a slip signal is generated upon selection of the switching signal.

Abstract: A method for communicating data is disclosed. The method includes receiving a sequence of electrical pulses during an interval having a pre-determined time period, the sequence of electrical pulses representing a message from one of a plurality of devices, determining the number of received electrical pulses in the sequence of electrical pulses, and decoding the message based on the determined number of electrical pulses received during the interval.

Abstract: A PPM signal demodulator for demodulating a PPM signal transmitted in a UWB radio communication system includes a rectifier for rectifying a received PPM signal to obtain an absolute value signal, integrator and comparators for integrating the absolute value signal for every first, second and third integral times and comparing the integrated values for the integral times, absolute value circuits for converting respective outputs of the integrator and comparators to corresponding absolute values, moving average circuits for moving-averaging respective outputs of the absolute value circuits, a determining circuit for generating demodulation data on the basis of the integrated and compared result by the integrator and comparator, and a main control for generating, on the basis of the outputs of the moving average circuits, integral interval control signals that control the first, second and third integral times to supply them to the respective integrator and comparators.

Abstract: It is an object of the present invention to provide a communications system for communication between two remote terminals, where even at very long distances between these two terminals and/or at very small signal-to-noise ratios a robust communication is possible. The invention achieves the goal set before by suggesting an inventive pulse position modulation scheme and a corresponding optical communications system. The system and method according to the invention are very well suited for communication with a satellite in deep space, for instance.

Abstract: According to an embodiment of the invention, a method and apparatus for signal modulation are described. According to an embodiment of the invention, a method comprises producing and transferring a modulated signal. The modulation of the signal is over a plurality of amplitude levels, including at least a first amplitude level, a second amplitude level and a third amplitude level, and over a plurality of time slots, including at least a first time slot, a second time slot, and a third time slot. The modulated signal transitions from the first amplitude level to the second amplitude level in the first phase slot, remains at the second amplitude level in the second time slot, and transitions from the second amplitude level to the third amplitude level in a third time slot.

Abstract: A system and method to optimize the quality of a modulated signal. In one aspect, an AM demodulator is used in conjunction with proper bandwidth selection of an FM signal. For example, the AM demodulator can be used to generate an instantaneous absolute value of the FM signal. The average value of the FM signal over a period of time is subtracted from the instantaneous absolute value in order to determine a variance in amplitude in the FM signal. In another aspect, several filters may be tested and the one having the lowest variance in amplitude may be used in order to select the filter having the desirable bandwidth.

Abstract: A method determines a duration of a frame in an impulse radio system for radio ranging. Channel state information of a channel between two transceivers is estimated periodically. A signal to noise and interference ratio is also estimated periodically. The frame duration of the frame is then determined according to the channel state information and the signal to noise and interference ratio.

Abstract: 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.

Abstract: A system in which one or more alarm sources (10) can wirelessly communicate with a receiver (30) to activate an alarm and does not contain any identification that indicates the communication's source (10). The system may include “repeaters” (40) whose function is to relay the communication from one station to another over distances longer than can be reached by a single transmitter (10). Apparatuses for transmitting (10), repeating (40), and receiving (30) are also disclosed, as well as a communication system comprised of various elements of these.

Abstract: A digital generator of phase shift modulation receives two binary coded numbers (F) and (P), that represent a requested frequency value and a requested phase value, respectively, and generates two pairs of phase-shifted signals a, b and c, d. One pair of the phase-shifted signals is intended to control one half bridge of a full-bridge converter, and the second pair is intended to control the other half bridge. Signal b is complementary to signal a having a 50% duty cycle with addition of dead times created by a first delay line (5). Signals c and d have the same parameters as signals a and b, with the exception that dead times are created by a second delay line (6). The frequency of generated signals is proportional to the requested frequency value (F) and the phase shift between pairs of signals is proportional to the requested phase value (P).

Abstract: An FM broadcast transmitter transmits a broadcast signal having a carrier at a broadcast frequency and sidebands, able to be transmitted at full power, within a transmission bandwidth around the carrier. It includes a source of a modulated FM stereo signal having a carrier at the broadcast frequency and having sidebands with a bandwidth less than the transmission bandwidth representing a stereo signal. It also includes a source of a modulated in-band-on-channel (IBOC) signal, having carrier pulses spaced relative to each other to represent the IBOC digital data signal encoded as a variable pulse width encoded signal, and a bandwidth within the transmission bandwidth not overlapping the FM stereo signal sidebands. A signal combiner combines the modulated FM stereo signal and the modulated IBOC signal to form the broadcast signal.

Abstract: The method is for decoding an incident UWB signal including successive incident pulses respectively received during successive Pulse Repetition Periods (PRP). The method includes determining a correlation matrix, whose terms respectively represent the correlation between all the M possible symbols transmitted in a current (PRP), and at least in the previous and in the next (PRP), and performing a correlation between an incident current pulse received during a current PRP and the M possible symbols transmitted in the current PRP and at least in the previous and in the next PRPs for obtaining a correlation vector. The method also includes preprocessing the correlation vector including reducing the effect of ISI from the correlation vector by using the correlation matrix, and decoding the preprocessed correlation vector for obtaining the bits of the transmitted symbol included in the incident received current pulse.

Abstract: Optimum usage of time diversity and significantly higher data rates are achieved by utilizing an adaptive Ultra-wideband impulse radio (UWB IR) transmission scheme based upon information about the channel state at a particular time instant. Through the use of channel state information, the transmission scheme is adjusted for the particular channel state. In particular, the system is adapted dynamically for each user by varying the number of pulses transmitted per bit in response to the channel state. The channel state is a dynamic parameter of the transmission system that is typically measured or estimated by the receiver. An adaptation element responds to the channel state information to determine a desired number of pulses per bit to be utilized in a transmission channel for subsequent UWB IR communication. This desired number of pulses per bit is then supplied to and used by an adaptive transmitter for subsequent transmission by a particular mobile station.

Abstract: A method and system for storing and transmitting data using variable pulse symbology over a fiber optic or ultra wide band system. Data is stored in memory, accessed and transformed into an electronic or photonic pulse and/or space which has a variable duration, the duration corresponding to the bit of data to be transmitted. The duration of the pulse and/or space is selected from a list of predetermined durations, each corresponding to a different base 10 number. The pulses and spaces may both be used to represent data, or the spaces may be used for meta data. Variable duration pulses may also be used to store data on an optical storage medium or fiber optic cable.

Abstract: A decoding method is carried out in a receiver configured to accept format information relating to sequences of input data, to use format information in the decoding of each input sequence, and to issue an acknowledgement signal in the event that an input sequence is successfully decoded. The method involves receiving a format message pertaining to a new input sequence, searching a candidate set of format indices an index best satisfying a criterion for matching to the format message, and selecting the index giving the best match. Before searching, the receiver reads the acknowledgement signals issued in response to the decoding or attempted decoding of recent input sequences. If the acknowledgement signals satisfy an appropriate condition, the search is limited to fewer than all the indices in the candidate set. The format information that corresponds to the selected index is used in decoding the new input sequence.

Abstract: A demodulated signal is to be generated by use of a first detection signal detected a presence/absence of a signal according to a correlation between a reception signal PPM-modulated at a pulse interval of T and a pulse variation width of ? and the reception signal delayed with a time (T+?), a second detection signal detected a presence/absence of a signal according to a correlation between the reception signal and the reception signal delayed with a time (T), and a third detection signal detected a presence/absence of a signal according to a correlation between the reception signal and the reception signal delayed with a time (T??). By thus combining a plurality of delayed detections, it is possible to obtain a UWB demodulating apparatus configured with a circuit suited for integrated circuit fabrication.

Abstract: The invention relates to an automation device, in which a multiplicity of physically distributed functional units communicate with each other by means of a common transmission protocol. The device has a microcontroller (110), which is assigned at least one clock generator (120) and one memory unit (150), and which is connected at least to one data source (140), which is designed to output a data bit-stream to be transmitted. A sequential sequence of equidistant samples of a sinusoidal time profile is stored in the memory unit (150), such that it can be called up, in such a manner that the samples can be output using either the clock of the first clock generator or the clock of the second clock generator, depending on the data bit-stream.

Abstract: A method estimates a channel impulse response in an ultra wide bandwidth (UWB) system. Multiple training sequences modulated at a chip rate are received. Each training sequence is sampled by parallel with multiple correlators at sampling rate substantially slower than the chip rate to obtain a samples over a time interval of the impulse response at a resolution substantially equal to the chip rate, and then estimating the channel impulse response from these samples.

Abstract: A method is provided for operating a wireless device. In this method, a first operation is performed on a wireless signal using a first group of wavelets arranged according to a first analog code word format (720). A second operation is then performed on the wireless signal using a second group of wavelets arranged according to a second analog code word format (740). The first code word format can be different in content and in size from the second code word format. By choosing different properties for each analog code word format, the device can optimize the performance of each operation. These operations can be performed in receiving process (800) or a transmission process (900).

Abstract: A communication receiver (30) includes a data receiver (34) that receives a pulse-position modulated signal (38). A clock circuit (70) separates a reference clock signal (36) into multiple coordinating clock signals A, B, and C. Multiple time integrators (78) are gated to generate multiple time-integrated signals in response to the pulse-position modulated signal (38) and the coordinating clock signals A, B, and C. A combiner (96) forms a demodulated signal from the time-integrated signals IntA, IntB, and IntC.

Abstract: Estimating error signals in a communication system may include determining a frequency error of a received RF signal utilizing a plurality of correlators, where one or more of the correlators may be fed with a carrier frequency of the received RF signal and a remaining portion of the plurality of correlators may be fed with one or more other carrier frequency. This carrier frequency fed to the remaining portion of the plurality of correlators may differ from the carrier frequency of the received RF signal. The received RF signal may comprise a primary synchronization channel (PSC) code for wideband code division multiple access (WCDMA). The carrier frequency of the received RF signal may be rotated in an I and Q coordinate system so as to generate the other carrier frequency.

Abstract: The invention allows the detection and processing in a radio signal received by a receiver, of any signal of “pulsed” type present in radio signals applied to the input of a radiofrequency receiver, the receiver having an analogue/digital converter for performing the coding into digital on N bits of P successive samples of the analogue signal applied to the input of the receiver and a computer for processing the said digital signals, characterized in that on the basis of a histogram of the rate of occupancy of the digitized samples, graded in ranges Fx of amplitude-increasing sample levels, is determined, from among the ranges Fx, a range Fn onwards of which the total number of digitized samples Nnor contained in the ranges Fn and those below Fn is greater than or equal to a normality threshold Nn, Nn being a number predetermined as a function of the sensitivity of the detection of pulsed signals that one wishes to achieve.

Abstract: This invention relates to a cooperation procedure between terminals in a UWB pulse telecommunications system. A source terminal transmits a data symbol for a recipient terminal in the form of a signal, called a source signal, constituted by a sequence of identical frames, each frame containing a pulse that is position-modulated by means of a PPM modulation alphabet. A relay terminal, receiving said source signal, detects a modulation position of a pulse in at least one frame of the signal received and transmits a relayed signal containing, in at least one predetermined subsequent frame of this signal, a pulse the position of which is obtained on the basis of the first position by a permutation of the PPM modulation alphabet.

Abstract: A data transmission apparatus is provided, which is capable of performing good communication with a noncontact data carrier under the circumstances where pulse noise is generated. A noise detection circuit in a reader/writer detects a generation period of noise contained in received signals. A communication time calculating circuit calculates estimated time for communication to be performed for an IC card. A timing signal generation unit determines transmission start timing based on the noise generation period and the estimated communication time.

Abstract: A pulse step modulator employs a plurality of series connected unit step power amplifier modules. Each module is turned on by a turn-on signal to provide a unit step voltage of a given value. An output circuit is connected to the modules for providing an output voltage to a load and wherein the output voltage is a multiple of the unit step voltages in dependence upon the number of modules that are turned on. The modules are sequentially turned on in a given order and are turned off in the reverse order. An encoder provides turn-on signals with each turn-on signal being applied to a selected one of the modules. The number of turn-on signals provided varies as a function of the magnitude of a time varying input signal. A controller alternately turns enables or disables (in a swapping manner) one of a pair of associated modules as the magnitude of the input signal increases and decreases.

Abstract: Aspects include methods and apparatuses for communicating in an ultra-wideband transmission. For example, some aspects include methods and apparatuses for multi-hop communication. For example, some aspects include a method of communicating data. The method includes receiving pulses indicative of a frame during a first time period and transmitting pulses indicative of the frame during a second time period to at least one device. The first and second time periods at least partially overlap. Other aspects include apparatus and devices for multi-hop communication.

Abstract: A direct sequence spread spectrum (DSSS) receiver (100) consistent with certain embodiments has a frequency generator (112) that generates a local oscillator signal without use of a piezoelectric crystal. A frequency converter (108) receives the local oscillator signal and mixes the local oscillator signal with a received DSSS signal to produce a down-converted signal. The received DSSS signal is encoded using a first set of DSSS code. A differential chip detector (116) receives the down-converted signal and converts the down-converted signal to a differentially detected signal. A correlator (120) receives the differentially detected signal and correlates the detected signal with a set of DSSS codes that are time-shifted from the first set of DSSS codes. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: A pulse frequency modulation oscillating circuit includes a reference voltage generator for generating a first reference voltage and a second reference voltage, a first comparison circuit for comparing a state signal with the first reference voltage, a second comparison circuit for comparing the state signal with the second reference voltage, an output circuit for outputting a pulse frequency modulation signal according to an under-voltage signal, and signals outputted from the first comparison circuit and from the second comparison circuit, a mode generation circuit for generating the state signal, and a mode decision circuit for outputting inverse signals of the signals outputted from the first comparison circuit or signals outputted from the output circuit to the mode generation circuit according to the pulse frequency modulation signal, the under-voltage signal, and the signals outputted from the first comparison circuit and from the second comparison circuit.

Abstract: Pulses of a signal, which are respectively contained in successive time windows, may be generated by a generator, and a control device may formulate a control signal for the generator including, for each pulse, an indication of its position in the corresponding window. The control device may include a processor to deliver for each time window, at a delivery frequency Fe greater than the pulse repetition frequency, successive groups of N bits together defining a digital cue of position of a pulse inside the window. Also, a converter may convert this digital position cue into the control signal temporally spread over the length (T) of the window and including the indication of position at an instant corresponding to the digital position cue. This makes it possible to position the pulse inside its window with a temporal precision equal to 1/N*Fe.

Abstract: A communication system compensates pulse positioned modulated data signals for channel induced intersymbol interference and extracts pulse positioned encoded data from a received signal corrupted with the channel induced intersymbol interference. The communication system has a transmitter and a receiver. The transmitter includes a modulation apparatus that has a symbol mapping circuit, which receives data symbols to be transmitted and maps the data symbols to a transmission code. The receiver has a demodulation apparatus to recover data symbols in the presence of the channel induced intersymbol interference. The demodulation apparatus has a sampling circuit in communication with a signal receiving circuit within the receiver to sample at a regular period received data symbols acquired by the receiving circuit. The samples of the data samples are retained by a sample retaining circuit in communication with the sampling circuit.

Abstract: A modulation method, referred to as dual phase pulse modulation (DPPM), represents digital data as a series of high and low pulses whose widths represent groups of M data bits, with both the high and low pulses representing successive M-bit groups. Each of the 2M possible data values for a group of M data bits uniquely corresponds to one of 2M distinct pulse widths. This modulation method is essentially clockless, with data being decoded from a signal by detecting each pulse's width with respect to the last transition. Power consumption is reduced by having M data bits represented for each pulse transition, and by using both the high and low pulses to represent data.

Abstract: A method is provided for performing a clear channel assessment in a wireless network. The method involves first listening for channel energy on a wireless channel. Whatever channel energy is heard over the wireless channel is demodulated into non-synchronized in-phase and non-synchronized quadrature phase components. Each of the non-synchronized in-phase and non-synchronized quadrature phase components are squared, and then the non-synchronized in-phase component is multiplied by the non-synchronized quadrature phase component to produce an I?Q product. The sum of the squared non-synchronized in-phase component, the inverse of the squared non-synchronized quadrature component, and double the I?Q product is determined as a clear channel assessment input value. A carrier signal detection function is then performed on the clear channel assessment input value to produce a clear channel assessment output value, which is used to determine whether a signal is present in the wireless channel.

Abstract: A radio transmitter and receiver arrangement includes a transmitter and a receiver. The transmitter generates an electromagnetic carrier that varies in frequency throughout a channel interval, and modulates the carrier with an information signal during the channel interval, whereby the carrier is modulated both in frequency and in accordance with the information signal during the channel interval. The receiver receives the carrier that is modulated both in frequency and in accordance with the information signal, generates a detection signal that varies in frequency throughout the channel interval, and mixes the carrier and the detection signal to recover the information signal.

Abstract: The invention is a method for pulse position modulating signals which are synchronized to clocked bit periods using a clock comprising the steps of generating two, three or n signals to mark the presence of digital ones during corresponding n time slots occurring during the same bit period. The two, three or n signals are combined into a single data channel to utilize abrupt phase changes of pulses in a carrier signal at a carrier frequency, the phase changes having a very short duration to mark the presence of digital ones only. The combination of the n signals into a single data channel comprises gating each of the n signals in a sequence of serially delayed time slots corresponding to each of the n signals during a portion of the same bit period in the single data channel during time positions reserved for unexpressed zeroes.