Abstract: Embodiments of the present invention pertain generally to methods and systems of processing a global positioning satellite (GPS) signal. More particularly, embodiments of the present invention provide an improved discriminator function that utilizes the early, prompt, and late correlator values. For example, the improved discriminator function may be normalized based on all three of the early, prompt, and late correlator values. The improved discriminator function behaves linearly across a prescribed region whose width depends on the separation between correlators.

Abstract: A frequency generation unit (FGU) in a communication device includes a voltage controlled oscillator (VCO), an adjustable filter having a capacitive element for wideband operation, a current source with variable gain, and chirp generation control circuitry (CGC) that is used to generate location signals. The FGU receives, from a reference device, at least one location signal control parameter that defines linear frequency slope characteristics for a location signal. The CGC configures, based on the at least one location signal control parameter, the gain and a polarity of the current source to generate a first current during a first time period for charging the capacitive element to generate a control signal that is coupled to the VCO to generate a first part of the location signal having the defined linear frequency slope characteristics, wherein the first part of the location signal is transmitted using a transceiver of the communication device.

Abstract: A pre-correlation filter determines the timing of a second pseudorandom number (“PRN”) code, using an image of the average chip shape formed for a first PRN code. The filter collects measurements corresponding to samples of a received signal over multiple code chips of the first PRN code at sample times that are asynchronous to code rate. A code phase decoder directs the measurements to accumulation registers that are associated with code chip ranges that are fractions of a code chip of the first PRN code based on the code phase angles of the samples in the first PRN code, to accumulate measurements relating to chip transitions in the first PRN code and measurements relating to chip transitions in the second PRN code. The chip edges of the second PRN code are detected from the image of average chip shape for the first PRN code formed from the accumulated measurements.

Abstract: A surface acoustic wave (SAW) expander based transmitter and correlator based receiver comprises SAW devices that perform expander or correlator functions based on the types of signals inputted to the SAW devices. The SAW devices incorporate chirp with adaptive interference and programmable coding capabilities. The SAW devices and method of operating the devices allow the implementation of very low power radios that overcome problems with temperature drift, lithography constraints and interference and jamming suffered by prior art implementations.

Abstract: Reduction in the detection accuracy of synchronization timing at the receiving end is prevented even if a GCL system changes in response to a GCL ID. A transmitter (100) has a GCL system generating section (101) for generating a GCL system signal, a scramble processing section (102) for scrambling the GCL system signal, and a sub-carrier mapping section (103) for arranging the scrambled GCL system signal in a sub-carrier in the direction of a frequency. With this, the peak width of the differential correlation value of the GCL system at the receiving end is narrowed, so that accurate synchronization timing can be detected at the receiving end.

Abstract: A low cost method and system for efficiently implementing channel estimation in a wireless communication system using any desired length of a fast Fourier transform (FFT) independent of burst type or signal structure. The hardware complexity required to perform the channel estimation to process a plurality of different burst types is reduced. Simple tail zero-padding is used when the length of FFT is extended to a desired length for more efficient computation.

Abstract: Aspects of a method and system for detection of long pulse bin 5 RADARs in the presence of Greenfield packets are presented. In one aspect of the system, a processor in a wireless communication device may receive a plurality of pulses via a received signal. The processor may select at least a portion of the received plurality of pulses. The processor may compute a time duration value and a pulse count value based on the selected at least a portion of the received plurality of pulses. The processor may determine whether the received signal comprises a RADAR transmission signal based on the computed time duration value and the computed pulse count value when the time duration value is greater than or equal to a threshold time duration value and the pulse count value is greater than or equal to a minimum pulse count threshold value.

Abstract: An identification tag is provided in which radio frequency (RF) circuitry and ultrawide bandwidth (UWB) circuitry are both provided on the same tag, along with some UWB-RF interface circuitry. The RF circuitry is used to detect when the identification tag must be accessed, and is used to connect the UWB circuitry with a power supply. The UWB circuitry then performs the necessary communication functions with a distant device and the power supply is again disconnected. In this way the power supply is only accessed when the UWB circuitry is needed and it's usable lifetime can be maximized.

Abstract: Methods and systems relating to Weil-based spreading codes are described herein. In an embodiment, a method includes generating a set of Weil sequences, adapting a plurality of sequences of the set of Weil sequences to form a first plurality of codes, and selecting a second plurality of codes from the first plurality of codes. A code of the first plurality of codes is selected based at least on a correlation associated with the code. Each code of the first plurality of codes has a predetermined length.

Abstract: A cellular communication system employs a plurality of bandwidths. The cellular communication system comprises a plurality of base stations (101, 103) each of which transmits a reference signal comprising a Generalised Chirp-Like, GCL, sequence. The length of the GCL sequence is dependent on the bandwidth employed by the base station (101, 103). A sequence generator (105) provides a first subset of GCL sequences for a first bandwidth selected from a set of possible GCL sequences for the first bandwidth in response to properties of a sub-sequence of GCL sequences. The sub-sequence has a length corresponding to a different bandwidth. Sequence processors (107, 109) select GCL sequences for base stations (101, 103) employing the first bandwidth from the first subset of GCL sequences. The invention exploits characteristics of GCL sequences to enable, facilitate or improve multiple bandwidth operation.

Abstract: A transmitter, receiver and communication technique. The transmitter is adapted to interleave a first pseudo-noise sequence with a second pseudo-noise sequence to provide a third pseudo-noise sequence. The third sequence is transmitted and then received by the inventive receiver. The first and second sequences are chosen so that an XOR of the two sequences produces a third, known-valid pseudo-noise sequence. The receiver includes an arrangement for receiving and correlating the third pseudo-noise sequence to provide a measure of a frequency of the transmitted signal. The receiver further includes an arrangement for downconverting and filtering the received signal to provide a filtered complex signal. A complex multiplier is included for effecting a complex multiplication of the filtered complex signal with a delayed version of the filtered complex signal to provide a product. The delayed version of the filtered signal is delayed by a chip period.

Abstract: Disclosed is a shared correlator for processing signals with different chip rates from respective channels. The shared correlator comprises a mode controller, a plurality of sub-correlators, a PRN code generator and a plurality of accumulators. The mode controller arranges channel allocations for respective IF signals down converted from the signals. The PRN code generator generates respective PRN codes for the respective IF signals according to the respective chip rates thereof. The sub-correlators perform correlation to the respective IF signals with the respective PRN codes to obtain respective correlating results. The accumulators accumulate the respective correlation results to obtain respective overall correlation gains of the respective IF signals according to the respective chip rates. Each sub-correlator comprises a plurality of correlator cells, correlating one IF signal with one PRN code corresponding thereto according to the chip rate of the IF signal.

Abstract: This document discusses, among other things, a system and method of detecting wideband signals of bandwidth X within a communications system having a coherency time constant of T. A synchronization signal is generated as a function of a chirp signal that sweeps a portion of bandwidth X. The synchronization signal is transmitted and a received as a wideband signal at a receiver. The receiver detects the synchronization signal within the wideband signal received at the receiver by generating a detection signal, correlating the received wideband signal with the detection signal and indicating when the synchronization signal is detected within the wideband signal. The detection signal is a complex conjugate of the synchronization signal.

Abstract: A method estimates a time of arrival of a signal received in a wireless communication system. An energy in a frame of a received signal is measured to determine a block in the frame, the block representing a coarse time of arrival of the received signal. Multiple time-delayed versions of a template signal are combined with the block of the received signal to select a particular template signal. The particular template signal identifies a particular chip representing a fine time of arrival of the received signal.

Abstract: A radio broadcast receiver is provided which reduces the degradation in quality of diversity-received signals. When a difference in level between a reception signal of a main antenna and a reception signal of a sub antenna is less than a predetermined threshold value, and when a difference in phase between the reception signal of the main antenna and the reception signal of the sub antenna exceeds another predetermined threshold value, a combination ratio of a combiner for combining outputs of a main tuner and of a sub tuner is set to 1:1, where in-phase combination type diversity is carried out. In other cases, the combination ratio of the combiner is switched between 1:0 and 0:1 depending on the occurrence of a multipath, where selection diversity is carried out.

Abstract: Disclosed is a method and an apparatus for channel estimation regarding electromagnetic wave multi-path characteristics between a sender and a receiver by using a chirp signal.

Abstract: The present invention presents a simple and novel channel estimation scheme for UWB communication systems. As disclosed herein, the present invention maximizes the extraction of information by incorporating a new generation of transmitted-reference (Tr) transceivers that utilize a single reference pulse(s) or a preamble of reference pulses to provide improved channel estimation while offering higher Bit Error Rate (BER) performance and data rates without diluting the transmitter power.

Abstract: A differential orthogonal modulation method and a differential orthogonal modulation apparatus using a repetition time interval difference of a chirp signal are disclosed. Such a differential orthogonal modulation method performed in a transmitter unit of a digital communication system comprises the steps of converting data having a serial bit format to be transmitted in the transmitter unit into a parallel format to create parallel input data, inputting the parallel input data into a symbol mapper, orthogonally modulating the parallel input data inputted into the symbol mapper to create modulated data comprised of differential bi-orthogonal functions, differentially encoding the modulated data to output encoded data, converting the encoded data into a serial bit format to create a baseband signal, and processing the baseband signal to create a transmission signal in a form of a chirp signal having a specific repetition time interval difference.

Abstract: A noise reduction circuit for improving a signal-to-noise ratio of an input signal corresponding to a predetermined sequence of chips, each of the chips having a value corresponding to Logic 0 or Logic 1. The noise reduction circuit comprises a sampling circuit for generating a first sequence of samples of the input signal; a controller for identifying samples in the first sequence of samples corresponding to Logic 0 chips and Logic 1 chips; and a randomizing circuit. The randomizing circuit generates a second sequence of samples by at least one of: i) shifting-positions within the first sequence of samples of some of the identified Logic 0 samples; and ii) shifting positions within the first sequence of samples of some of the identified Logic 1 samples corresponding to Logic 1 chips. The first and second sequences of samples may then be combined to generate an improved composite signal.

Abstract: A digital broadcast receiving apparatus for receiving a broadcast signal generated by combining sub signals modulated using a random sequence generated based on an initial value set in accordance with a frequency of a broadcast channel by a signal transmission control use signal and a main signal generated based on information source data and reproducing the information source data contained in the received broadcast signal.

Abstract: A code division, multiple access (CDMA) receiver includes an RF section for receiving a CDMA signal through a channel; a circuit for determining an instantaneous total received power (Io) of the received CDMA signal; and a searcher that is one of enabled for operation or disabled from operation in accordance with value of Io. The circuit includes a comparator for comparing Io against a threshold, and for generating a searcher trigger signal only when Io exceeds the threshold or, preferably, for generating the searcher trigger signal if Io does not exceed the threshold, within some predetermined period of time.

Abstract: A method of minimizing detectability of an electronically communicated message is disclosed. A predetermined frequency modulation pattern about a nominal transmission frequency is defined. The predetermined frequency modulation pattern is suitable to vary the nominal transmission frequency during a dwell period. The dwell period is divided into a plurality of sub-dwell periods. Each sub-dwell period has a nominal sub-frequency assigned thereto according to the predetermined frequency modulation pattern. The plurality of sub-dwell periods and the respective assigned nominal sub-frequencies are randomly or pseudo-randomly ordered. The message is transmitted according to the random or pseudo-random ordering of the nominal sub-frequencies.

Abstract: A method including searching for a communication channel by activating a receiver having a radio frequency (RF) module and a baseband module for storing a portion of received signals within a first time period, de-activating the RF module of the receiver, and background processing the portion of the received signals with a variable clock rate within a second time period.

Abstract: A new modulation scheme in UWB communications is introduced. This modulation technique utilizes multiple orthogonal transmitted-reference pulses for UWB channelization. The proposed UWB receiver samples the second order statistical function at both zero and non-zero lags and matches the samples to stored second order statistical functions, thus sampling and matching the shape of second order statistical functions rather than just the shape of the received pulses.

Abstract: A compound chirp is provided in a received signal to permit a receiver to synchronize to the received signal. The compound chirp has temporally overlapping up frequency and down frequency components.

Abstract: Methods and systems for communication systems are disclosed. Chirp signals generated according to a chirp rate and carrier frequency are used for communication. The chirp rate can be determined by solving integrals or by simulation of transmission parameters. A chirp signal is transmitted from a base station and delayed versions of the chirp signals are created. The delayed versions are generated by the chirp signal reflecting off of reflectors. A receiving station receives an incoming signal. The incoming signal includes the LOS signal plus delayed versions, noise and/or interference. Unwanted signals, either LOS or delayed versions, noise and/or interference are removed from the incoming signal to obtain the desired chirp signal. Using the chirp rate, the chirp signal is converted to a corresponding digital signal.

Abstract: Systems and methods are described here for locating the position of a mobile terminal in a cellular communications system. A base station in the cellular communication system broadcasts a communication signal having embedded therein a navigation signal. The navigation signal uses a chirp technique in which the chirp signal includes two portions, an up-chirp portion and a down-chirp portion. Each portion of the chirp signal is synchronized with a frame in the communication signal. The chirp navigation signal is at a power level much lower than the communication signal so as not to interfere with the communication signal. A mobile terminal generates a corresponding chirp signal to correlate with the incoming signal and to extract the navigation signal. The mobile terminal uses the detected navigation signal to determine a time of arrival of the communication signal for use in determining the position of the mobile terminal either at the terminal or to send to a network center for location processing.

Abstract: This invention modulates data onto a radio channel in such a way that the deleterious effects of the channel are reduced. This is accomplished in three steps: first, the information signal is modulated using a phase-differential modulation scheme. Second, the modulated signal is spread in both time and frequency by passing it through a dispersive filter, transmitting it through the channel, and removing the spreading using a dispersive filter in the receiver with the opposite characteristics of the filter in the transmitter. The third step, after demodulation, is to pass the signal through a low-pass filter to gather up the signal energy which has been dispersed by the channel. All three of these steps can be implemented with simple functional blocks, making this system very inexpensive to implement. Also included are two methods for enhancing the data throughput of the basic system, making it more bandwidth efficient.

Abstract: A circuit and method for controlling a spread spectrum transition are presented comprising a first circuit and a second circuit. The first circuit may be configured to generate a clock signal in response to (i) a reference signal, (ii) a sequence of spread spectrum ROM codes, and (iii) a command signal. The second circuit may be configured to synchronize the command signal to a feedback signal. The sequence of spread spectrum ROM codes may be generated according to a predetermined mathematical formula and optimized in accordance with predetermined criteria.

Abstract: In a chip radio communication system, a novel technique for increasing the number of transmitters, or users, that can be simultaneously accommodated in the communication system and the data capacity of the system without increasing frequency bandwidth. A system may include plural transmitters, receivers, and a central station for establishing chirp radio communications. Each receiver may discriminate between chirp radio transmitter type based on the differing chirp signal characteristics.

Abstract: An optical binary code transmission system comprising a sender comprising: means for generating a light beam; phase-shifter means; attenuator means whereby the intensity of the lateral modes is sufficiently low for there to exist at the most only one photon in the lateral modes. The phase-shifter means of the sender impose a phase-shift that is chosen randomly to be equal either to 0 or to &pgr;/2 for a first bit value or either to &pgr;/or to 3&pgr;/2 for a second bit value, and the receiver comprising means for detecting the presence of a photon in the first lateral mode and means for detecting the presence of a photon in the second lateral mode, a first bit value being detected if the presence of a photon is detected in the first lateral mode and a second bit value being detected if the presence of a photon is detected in the second lateral mode.

Abstract: The transmission/reception apparatus of the present invention, on its transmitting side, performs sweeping by sweep circuit 106 that changes with time the central frequency of a modulated signal according to a predetermined sweep pattern of frequency change controller 107 and then transmits the signal. On its receiving side, it detects a received signal while sweeping the central frequency with the same sweep pattern as that on the transmitting side created by frequency change controller 112. In this way, signals are transmitted correctly.

Abstract: Methods and apparatus for detecting a transmission of digital radio frequency chirps are disclosed. A series of digital chirps, which are emitted from a remote transmitter, are received by an antenna and then fed into an RF receiver. In one preferred embodiment of the invention, noise is extracted from the received RF chirp waveform using a Kalman filter. Useful information is then extracted from the received RF chirp waveform using one of several novel detection methods.

Abstract: An RF transceiver with a low power chirp acquisition mode includes a pulse detection circuit, which initiates a low power chirp acquisition mode when an appropriate input pulse is received. While in chirp acquisition mode, all transceiver circuitry not required to determine the chirp rate is powered down, a low power fast-hopping LO generator is powered up to provide one or more LO signals to demodulate the incoming signal, and an active bandpass filter connected to filter the demodulated output is arranged to extend the width of its passband to include the chirp rate. The filtered signal is digitized with an ADC and processed to determine the incoming signal's chirp rate. The low power LO generator comprises a look-up table which provides a plurality of digital output word sequences, each of which represents a discrete LO frequency, to a sine-weighted DAC. The resulting varying frequency analog output signal is multiplied to produce the discrete LO signals needed to demodulate the input signal.

Abstract: A system and method for generating an ultra-wide band communication signal having data occurring a specific frequencies precisely excised at baseband. The data to be transmitted is transformed into a function of time where the data to be excised can be removed in the time domain. After the data has been successfully removed in the time domain, the data is then transmitted in the frequency domain in which no data is transmitted at the frequencies where the data was precisely excised.

Abstract: A chirp waveform is employed in establishing timing synchronization between nodes of a data communication network. In one embodiment, the chirp waveform is combined with a waveform modulated with data to form a synchronization waveform. The receiver of the synchronization waveform determines an alignment of the chirp waveform to a template chirp waveform to synchronize timing between nodes.

Abstract: A fast-tracking discrimination approach provides rapid acquisition useful for direct-sequence spread spectrum applications. In one example embodiment, the present invention is directed to a communication system receiver that operates a linearly normalizing discrimination process on a signal modulated by a waveform having a bit rate defined in terms of a bit-pulse duration (chip). For at least one reference code, correlation results are obtained from several timing offsets of the signal, where each timing offset is separated by a fixed chip offset. Using at least three consecutive ones of these correlation results, assuming that the correlation energy of band-limited signals is approximately quadratic, an accurate phase error is obtained for synchronizing the received signal.

Abstract: Transmission method in which angle-modulated pulses with temporally opposite angle modulation are generated in the receiver during the duration of the pulse, which pulses are superimposed by means of a first superimposing element (8, 9), in each case in pairs, into a folded pulse, whereby the folded pulses transmitted to the receiver, after a modulation process, carry information impressed upon them, and these folded pulses are filtered at the receiver through two parallel-connected, complementary dispersion filters with frequency-dependent group delay characteristics, whereby the frequency-dependent group delay characteristics of the two dispersion filters are matched to the angle-modulation, in each case, of one of the two pulses forming in their superposition the folded pulse, in such a way that at the output of the dispersion filter, in each case, a combined signal appears that consists of one compressed pulse with increased amplitude and one expanded pulse with decreased amplitude, whereby the signals at

Abstract: A system for communicating with plural remote transmitters in which the transmitters send messages without a common synchronization source or polling by a controlling receiver. In one embodiment, the system uses the time position of frequency chirp signals to encode the identity and/or other information sent from the receiver. The system may use relatively low cost transmitters because the transmitters do not need to have a message or clocking signal receiving capability and the internal clocking signal source within the transmitter may be a relatively inexpensive device or circuit.

Abstract: Methods and systems for communication systems are disclosed. Chirp signals generated according to a chirp rate and carrier frequency are used for communication. The chirp rate can be determined by solving integrals or by simulation of transmission parameters. A chirp signal is transmitted from a base station and delayed versions of the chirp signals are created. The delayed versions are generated by the chirp signal reflecting off of reflectors. A receiving station receives an incoming signal. The incoming signal includes the LOS signal plus delayed versions, noise and/or interference. Unwanted signals, either LOS or delayed versions, noise and/or interference are removed from the incoming signal to obtain the desired chirp signal. Using the chirp rate, the chirp signal is converted to a corresponding digital signal.

Abstract: A novel and useful windowing mechanism for reducing the out of band harmonics of an output transmit signal. The windowing mechanism functions to smooth the transition between two consecutive transmit waveforms. The mechanism of the present invention is particularly useful in communication systems characterized by consecutively transmitted symbols whereby the concatenation of transmitted waveforms causes discontinuities between symbols. The windowing mechanism is operative to reduce the effect of these discontinuities to reduce out of band harmonics of the transmitted output signal. The windowing mechanism extend each transmit waveform both earlier and later in time thus creating extending waveform portions on either end of the transmit waveform. The extended portions are then multiplied by a suitable windowing function and the result is summed with the next transmit waveforms.

Abstract: A method and system generates a modulated chirp signal in accordance with the present invention. A phase-locked loop output signal is generated, together with a sampled feedback signal from a voltage controlled oscillator. The sampled feedback signal is received within a quadrature I/Q phase modulator. I/Q quadrature signals are generated from an I/Q generator circuit to the quadrature I/Q phase modulator to produce a desired modulation of a sampled feedback signal as a string of +/−90 degree phase shifts to create a desired offset at the voltage controlled oscillator. The I/Q quadrature signals are chirp modulated and the resultant phase-locked loop output signal is chirp modulated by the chirp signal that comprises a sequence of chirps having a reference chirp followed by a plurality of data chirps.

Abstract: The present invention includes a chirp transmission means for generating and emanating chirps. In general, a chirp is a pulse, waveform or propagated signal which may be characterized by a mathematical function. In one embodiment, the mathematical function comprises a relationship between frequency and time. The invention also includes a chirp reception means for receiving chirps without the need for tuning to a carrier waveform. The reception means is capable of extracting digital data from the received chirps. In alternative embodiments of the invention, the chirps may convey voice, video or other signals.

Abstract: To surely detect a frequency shift and a timing difference of a received signal making use of a chirp signal even when the C/N ratio of the received signal is low by resolving the problem of resolution of FFT processing, a frequency and timing synchronization circuit comprises: a chirp signal generator (6) for generating a reference chirp signal and a conjugate complex signal of the reference chirp signal; a first demodulator (7) for obtaining a first in-phase complex signal and a first quadrature-phase complex signal by demodulating the received signal with the reference chirp signal and the conjugate complex signal a frequency offset circuit (5) for obtaining an offset signal by shifting a frequency of the received signal; a second demodulator (8) for obtaining a second in-phase complex signal and a second quadrature-phase complex signal by demodulating the offset signal with the reference chirp signal and the conjugate complex signal; and a detector unit (9) for detecting the frequency shift and a differen

Abstract: Method for wireless information transfer, in particular for mobile communications, in which an input signal (s1, g4) is subjected to a modulation in a transmitter (2 to 8) and reaches a receiver (11 to 15) through a transmission channel, whereby angle modulated pulses, carrying information and possessing a frequency spectrum, are generated in the transmitter in such a way that they can be time compressed in a receiver by means of a filter (13) with frequency dependent, differential delay time, also known as group delay, in such a way, that pulses arise with shortened duration and increased amplitude compared to the emitted pulses, and at least a portion of the information is imprinted onto the pulses using an additional modulation, independent of the angle modulation, and/or is used for controlling a parameter of the angle modulation that can then be registered in the receiver.

Abstract: Method for wireless information transfer, in particular for mobile communications, in which an input signal (s1, g4) is subjected to a modulation in a transmitter (2 to 8) and reaches a receiver (11 to 15) through a transmission channel, whereby angle modulated pulses, carrying information and possessing a frequency spectrum, are generated in the transmitter in such a way that they can be time compressed in a receiver by means of a filter (13) with frequency dependent, differential delay time, also known as group delay, in such a way, that pulses arise with shortened duration and increased amplitude compared to the emitted pulses, and at least a portion of the information is imprinted onto the pulses using an additional modulation, independent of the angle modulation, arid/or is used for controlling a parameter of the angle modulation that can then be registered in the receiver.

Abstract: The present invention is to provide a phase offset calculation method of binary code being used in a mobile communication system, a binary code error detection method for detecting errors occurred in the received binary code by using the phase offset of the binary code and a synchronization method of binary code greatly reducing an acquisition time by using the error detection. The present invention to calculate the phase offset of binary code includes a step of receiving the binary code Ti(C) shifting with a period n, a step of calculating a binary code weight accumulation value by selecting the accumulator function weight value l of the binary code and then by applying the weight value to said binary code, a step of obtaining a phase shift value by shifting the phase of the binary code weight accumulator value, and a step of calculating the phase offset of the binary code by performing an operation of modulo n on said binary code weight accumulator value.

Abstract: A waveform to be transmitted as a burst within a channel that is used for the synchronization of unsynchronized wireless communications terminals in a wireless communications system, and a method of synchronization involving the waveform, that consists of a composite waveform. The composite waveform comprises two or more component waveforms, wherein each of the two or more component waveforms has a known frequency variation throughout the burst. The composite waveform has a composite bandwidth on an order of an available channel bandwidth and each of said two or more component waveforms have a component bandwidth on the order of the available channel bandwidth. Furthermore, a range of values for the differences between the instantaneous frequencies of two of said two or more component waveforms is on an order of twice of said available channel bandwidth.

Abstract: A method of acquiring a communications signal is provided. The method includes the steps of storing a forward chirp sync segment (106) of an auto-correlating forward chirp sync (102) and storing a reverse chirp sync segment (108) of a symmetric auto-correlating reverse chirp sync (104). A header comprising of either a forward chirp sync FCS (102) or a reverse chirp sync RCS (104), a predetermined number of data blocks comprising a data frame (308), and the symmetric auto-correlating trailer is received. The header, the data blocks, and the symmetric trailer are susceptible to frequency error. The method correlates the FCS segment (106) with the auto-correlating FCS (102) to provide a FCS correlation signal (312) and correlates the RCS segment (104) with the auto-correlating RCS (108) to provide a RCS correlation signal (314). The method determines the frequency error, symbol timing, and frame timing based upon the FCS correlation signal (312) and the RCS correlation signal (314).

Abstract: Identity transform filters, such as sin(x)/x filters, are used to coherently fragment the frequency continuum of a wideband waveform, such as an ultra wideband radar signal, into a plurality of spectral segments that are capable of fitting into unoccupied spectral regions of a partially occupied electromagnetic spectrum. The wideband waveform has a bandwidth that falls within the partially occupied portion of the electromagnetic spectrum, and exceeds that of any unoccupied spectral region. The total useable bandwidth of the unoccupied regions is at least equal to that of the wideband waveform.