Abstract: A technique for demodulating secondary data from a hierarchically modulated signal includes a number of steps. A gray coded eight phase shift key (8-PSK) hierarchically modulated signal is received that includes primary data and secondary data. An imaginary portion of the signal is determined and a real portion of the signal is determined. An absolute value of the real portion of the signal may then be subtracted from an absolute value of the imaginary portion of the signal to provide the secondary data. The gray coded 8-PSK hierarchically modulated signal may be a uniform gray coded 8-PSK hierarchically modulated signal or a non-uniform gray coded 8-PSK hierarchically modulated signal.

Abstract: The method of selecting an optimum mode of operation of the QAM modem comprising (A) using a host interface to select a pair of states, the first state being an initial state; the second state being an intermediate state; and (B) causing a state machine to progress from the initial state to a final state via the intermediate state to optimize the performance of the QAM modem.

Abstract: A transceiver system including a common receiver and transmitter oscillator. The transceiver system may include transmitter circuitry, receiver circuitry, and a first oscillator. The first oscillator may provide a transmit frequency to a mixer in the transmitter circuitry to generate a transmitter RF signal. Furthermore, the first oscillator may also provide the transmit frequency to a first stage mixer in the receiver circuitry to down-convert a receiver RF signal from a receive frequency to an intermediate frequency (IF). The receiver circuitry may include a second oscillator and a second stage mixer. The second oscillator may provide an IF frequency to the second stage mixer to down-convert receiver signals at IF to a lower frequency. The receiver circuitry may filter out transmitter RF feedthrough signals without using a SAW filter. The transmitter circuitry, the receiver circuitry, and the first oscillator may be included in a single IC.

Abstract: A mixer (114) includes a phase clock generator (404), a latch (420), and a multiplier (118). The phase clock generator (404) provides a plurality of phase clock signals. The latch (420) is coupled to the phase clock generator (404) via a first plurality of conductors (410) and provides a plurality of resynchronized phase clock signals. The multiplier (118) is coupled to the latch (420) via a second plurality of conductors (430) and mixes an input signal using the plurality of resynchronized phase clock signals to provide a mixed output signal. The second plurality of conductors (430) is characterized as having a lower end-to-end impedance than an end-to-end impedance of the first plurality of conductors (410).

Abstract: Methods and apparatuses employing symmetrical phase-shift keying (SPSK) for data modulation and demodulation. Each symbol in a transmission signal carries n-bit information and is transmitted with one of 2n+1 directions. Half directions among the 2n+1 directions are regarded as default directions and the remaining are regarded as complementary directions. Each default direction has a corresponding complementary direction with a phase difference of ? and representing the same n-bit information as the default direction. The phase difference between any two successive symbols after modulation is less than or equal to ?/2.

Abstract: Briefly, a method and apparatus to calculate cross-correlation values of complex binary sequences are provided. The apparatus may include a transformation unit and a cross-correlator. The cross-correlator may include a cross-correlation controller to provide, based on a type bit and a sign bit, a real component and/or an imaginary component of signals of complex binary sequences to a real accumulator and/or to an imaginary accumulator.

Abstract: In one embodiment, a demapper uses two hybrid-QPSK constellations to demap pairs of equalized data symbols recovered from 16-QAM, DCM OFDM symbols, wherein the equalized data symbols in a pair correspond to the same four-bit group. A first hybrid-QPSK constellation is generated by combining the real components of both 16-QAM mapping constellations onto one coordinate plane. The demapper generates a first set of two decision variables by combining the real components of each equalized data symbol in a pair to correspond to the first hybrid-QPSK coordinate plane. A log-likelihood ratio is then calculated for both decision variables in the set to determine likelihood estimates for the first and second bits of the four-bit group. This process is repeated for the imaginary components of each corresponding pair of equalized data symbols to generate likelihood estimates for the third and fourth bits of the four-bit group.

Abstract: The invention is a terminal, system and method for providing inter-frequency and inter-system handovers. A terminal 20? in accordance with the invention includes at least one radio transceiver including P radio receivers and at least one transmitter (16) with P being an integer at least equal to 2. Each radio receiver includes an antenna (41) which receives M encoded data streams. A terminal controller 18 controls the that at least one radio transceiver.

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: The invention relates to a method for determining the sampling instant of a clock signal (ti) for a circuit for determining symbols (Se) from a digitized signal (sd, S) which is coupled to at least one quadrature signal pair of a modulation method (QAM), wherein the digitized signal is converted to polar signal coordinates (R, ?) with a radial component (R). In order to implement an optimization of the sampling instant independently of the frequency or phase offset of the carrier control on which the symbols depend, it is proposed that the rate-of-occurrence distribution of the signals over the radii, which are assigned to the modulation method within the complex plane, be considered at different sampling phases (?i, ?i2) as the quality value (G, G*), and that the better quality value be selected from among the multiple rate-of-occurrence determinations. The variation of the sampling phase assigned to this value is subsequently employed to correct the sampling clock signal (ti).

Abstract: A demodulator with a phase-adjusting function including a detector including a delay detector delaying an input signal in delaying stages using a first clock obtained by frequency-dividing a sampling-clock at a first-ratio to output a delayed modulated signal, the sampling-clock having a predetermined frequency and a predetermined clock number, and a phase-adjustor which, when the stage number of the delaying stages obtained by dividing the predetermined clock number at the first-ratio does not become an integer, delays the input modulated signal using a second clock, the second clock obtained by frequency-dividing the sampling clock at a second-ratio, a ratio between the second-ratio and the first-ratio corresponding to a shortage in a final delaying stage to produce a phase-adjusted modulated signal that has been adjusted to cause the phase of the input modulated signal to coincide with the phase of the delayed modulated signal.

Abstract: A pipelined adaptive decision feedback equalizer (DFE). The pipelined ADFE comprises a pre-processing unit, an adder, a feedback filter (FBF), a slicer, a delay unit, a weight-update block and a mapping circuit. The pre-processing unit comprising a plurality of PP coefficients filters a signal received from a channel, and outputs a PP output signal to the adder. The slicer outputs a decision signal based on an added signal output from the adder. The FBF comprising a plurality of FBF coefficients receives the decision signal and generates a FBF output signal to the delay unit. The delay unit outputs a delayed signal to the adder. The weight-update block adapts the FBF coefficients to cancel the post-cursor ISI and selects a plurality of coefficients from the FBF coefficients. The mapping circuit translates the FFF coefficients by a predetermined method to generate the PP coefficients output to the pre-processing unit.

Abstract: A quadrature bandpass-sampling analog-to-digital demodulator (QBS-ADD) is provided. A radio frequency (RF) signal is received by a junction summer, which subtracts an in-phase feedback signal and a quadrature feedback signal from the RF signal to produce an error signal. The error signal is then bandpassed and amplified by the RF bandpass filter/amplifier. The amplified signal is bandpass-sampled by two low-resolution analog-to-digital converters clocking in quadrature, and is demodulated and converted into a digital in-phase signal and a digital quadrature signal. The down converted in-phase and quadrature signals are multiplied with two quadrature clocks. The results are converted to two analog signals and fed back to the RF input at the junction summer.

Abstract: A communications system reduces downconverter inaccuracies in time-domain measurements or samples of received microwave communications I and Q complex signals by converting received signal to baseband taking measurements or samples of the I and Q waveforms at differing phase shifts of a demodulating carrier signal for a local oscillator or carrier tracking loop used during downconversion so that I and Q imbalances may be detected and removed by lowpass equivalent averaging for improved characterization of downconverters or for improved signal reception. In the preferred form, the phase shifts are 0 and ?/2 for a conventional measurement, and then at ?, and ?+?/2, with ?=?/4+m?/2 for an integer m for the second measurement where I and Q imbalances and baseband nonlinearities are indicated by differences between the two measured or sampled signals, where ? provides for optimum error detection for reducing the errors by averaging the measurements.

Abstract: A wireless receiver includes a hardware (HW) block, a converter block and a digital signal processor (DSP). The HW block receives a wireless signal having a first DC Offset Component (DCOC), removes a portion of the first DCOC to produce a residual DCOC centered at DC, and generates parameters that estimate the residual DCOC. The converter block is coupled to the HW block and receives the residual DCOC centered at DC and converts it to a residual DCOC centered at IF. The DSP is coupled to the HW block and the converter block and receives the residual DCOC centered at IF from the converter block and the parameters from the HW block, and uses the parameters to eliminate the residual DCOC, and generate a baseband signal that is substantially free of the first DCOC and the residual DCOC.

Abstract: A method for compensating Inphase-Quadrature (IQ) imbalance in a receiver includes: generating a gain compensation parameter, a first phase compensation parameter, and a second phase compensation parameter according to a first signal on the I path and a second signal on the Q path of the receiver; and performing compensation on the I path and the Q path according to the gain compensation parameter, the first and the second phase compensation parameters.

Abstract: A technique of decoding a biphase signal comprises sampling the biphase signal to obtain phase sample values and sampling the biphase signal to obtain magnitude sample values. A first digital signal is derived from the phase sample values and associated bit combinations are formed from the first digital signal. A decision is made whether the bit combination is an erroneous bit combination, and a probability check is performed to obtain probability values that decide which parts of the erroneous bit combination are true and which are false. A corrected bit combination is generated from the obtained probability values, and a second digital signal is generated whose data states are formed from the valid bit combination and, in the presence of an erroneous bit combination, from the corrected bit combination.

Abstract: A carrier lock detector for a QPSK or 4-QAM system implements a lock detection algorithm that maps detected signals onto one of first and second areas associated with nominal states defined by (I2?I3)·(Q2?Q3) and Q1?Q2·(I1 I2I3+ I1I2I3)+( I1?I2)·(Q1 Q2Q3+ Q1Q2Q3), or alternatively, by ( I1?I2· Q2?Q3)+( Q1?Q2· I2?I3), respectively. When detected signals map onto one of the first areas, a first signal is generated. When detected signals map onto one of the second areas, a second signal is generated. When a difference between the first and second signals exceeds a threshold, a carrier lock detection signal is generated to enable a decoder. The carrier lock detector is able to detect carrier lock at a raw BER of 1e-2 or greater at a very low signal-to-noise ratio.

Abstract: According to some embodiments, distances associated with a Trellis decoder are determined.

Abstract: A system for estimating the modulation index and frequency offset of a CPM signal. An estimator filters the received signal and utilizes a training sequence to determine the modulation index and frequency offset of the CPM signal. The estimator can also include a post-processing step to eliminate all or part of a bias that might be created by the estimator.

Abstract: An encoder sampling a first phase (A) signal and second phase (B) signal with phases differing from each other by about 90 degrees at the same timing, converting them from an analog to digital format, and detecting an angle signal based on the obtained digital signals, provided with offset detection circuits using a second phase A/D converted value (BD) of when a first phase A/D converted value (AD) is near a first value (XA) to find a second phase (B) offset value (Bofs), using a first phase A/D converted value (AD)of when a second phase A/D converted value (BD) is near a second value (XB) to find a first phase (A) offset value (Aofs), and using the currently found first offset value (Aofs) for the first value (XA) and the currently found second offset value (Bofs) for the second value (XB)when calculating the next first offset value (Aofs) and second offset value (Bofs) and a subtraction circuits using a first offset value (Aofs) and second offset value (Bofs) to correct offsets of the first phase signal an

Abstract: A system and method for estimating the frequency offset experienced between carrier and local oscillator frequencies in communication systems using quadrature modulation. The invention exploits the geometry of the quadrature modulation constellation and estimates actual offset within a predefined carrier offset value without requiring data estimation.

Abstract: An integrated circuit arrangement is provided for converting a high-frequency bandpass signal to a low-frequency quadrature signal with a first in-phase component and a first quadrature-phase component, which has: an amplifier arrangement, which is designed to generate an amplified signal and has a first amplifier stage for amplifying the high-frequency bandpass signal, a mixer unit with a first mixer to provide the first in-phase component and a second mixer to provide the first quadrature-phase component, and a driver amplifier, which is designed to generate a local oscillator signal. According to the invention, between the amplifier arrangement and the mixer unit a polyphase filter is disposed, which converts the amplified signal to a complex-valued polyphase signal with a second in-phase component and a second quadrature phase component.

Abstract: An apparatus for recovering a carrier is disclosed, for recovering a carrier correctly even though ghost exists in a signal received in a television, which includes a signal converter outputting baseband I, Q signals by multiplying digitized passband I, Q signals by a complex carrier according to a phase error; first and second filters removing data components of the baseband I, Q signals; a divider dividing a signal outputted from the second filter by a signal outputted from the first filter; a multiplier multiplying a signal outputted from the divider by the baseband I signal delayed for a predetermined time period; and an oscillator generating a complex carrier according to a signal outputted from the multiplier.

Abstract: A demodulation circuit can perform a capturing operation although afrequency error is large. A phase comparator out puts a predetermined value other than 0 as a determination result of a phase error when a phase error of a carrier wave is large and a signal point is located at a predetermined position. A loop filter outputs a negative minimum value to an integrator when an integrated value of a determination result reaches a positive maximum value of a limiter. Thus, when a phase error is large, a value changing from a negative minimum value to a positive maximum value is output from the loop filter, thereby realizing a broad synchronous capture range.

Abstract: An improved apparatus for receiving BS digital broadcast is disclosed. The apparatus for receiving BS digital broadcast of the present invention has first to third filters and a selective complex calculator circuit. Each of the first to third filters 18 to 20 identifies the modulation technique applied to the received signal, by the modulation identification signals A0, A1 received from a timing generator circuit 25, and filters a phase error signal PED according to the identified modulation technique. The selective complex calculator circuit 21 shifts the phase of a signal point indicated by an I signal ADI1 and a Q signal ADQ1 absolute-phased by an absolute-phasing section 14, by a phase corresponding to the phase error signal filtered by the first to third filters 18 to 20.

Abstract: Improved signal reception is provided in a digital television signal received by identifying and mitigating multipath signal effects prior to demodulation and equalization. According to an exemplary embodiment, a digital television signal is received having multipath signal effects which cause a plurality of ripples in the received signal. The amplitude of at least one of the ripples and the frequency separation between at least two of the ripples are detected. At least one of an antenna and a tuner is controlled in dependence upon the detection. Signal demodulation and equalization operations may be performed after at least one of the antenna and the tuner is controlled.

Abstract: Briefly, a method and apparatus to calculate cross-correlation values of complex binary sequences are provided. The apparatus may include a transformation unit and a cross-correlator. The cross-correlator may include a cross-correlation controller to provide, based on a type bit and a sign bit, a real component and/or an imaginary component of signals of complex binary sequences to a real accumulator and/or to an imaginary accumulator.

Abstract: A direct conversion circuit that includes an in-phase and quadrature-phase feedback path that reduces Direct Current (DC) offset. Each feedback path includes a compensating mixer that generates an error correction voltage that is passed through a loop gain circuit and an integrator. The integrated signal is applied to the output of a low pass filter that operates on the down-converted baseband signal. The direction conversion circuit may not only down convert the received modulated signal using a down-converting mixer into a baseband signal, but also, after performing a passive low pass filtering to remove higher-order components, performs up-conversion of the baseband signal using an up-converting mixer. This allows active elements operating on the up-converted signal to introduce less 1/f noise.

Abstract: A direct conversion receiver (DCR) calibrated for phase and gain mismatch is provided. The DCR comprises a poly-phase filter that generates mismatched in-phase and quadrature-phase differential signals; the in-phase differential signal is mixed with first and second local oscillation signals; the quadrature-phase differential signal is mixed with third and fourth local oscillation signals; the first and second local oscillation signals have a first adjustable phase mismatch, and the third and fourth oscillation signals have a second adjustable phase mismatch; A mismatch estimation unit (MEU) estimates the entire phase/gain mismatch (signal distortion) of the DCR, The first and second adjustable phase mismatches are adjusted so that the signal distortion of the DCR, as estimated by the MEU is minimized. Thereafter, reduced-component DCRs (without an MEU), calibrated for the mismatches of a poly-phase filter, may be mass produced.

Abstract: A method for multi-user detection includes receiving a complex input signal due to a superposition of waveforms encoding symbols in a constellation of fixed magnitude and variable phase, which symbols are transmitted respectively by a plurality of transmitters in a common frequency band. The complex input signal is sampled at sampling intervals over the duration of an observation period to provide a sequence of complex samples. The sequence of complex samples is processed to determine soft decision values corresponding to the symbols transmitted by the plurality of the transmitters in the observation period, while constraining the soft decision values to a circle in a complex plane. The soft decision values are projected onto the constellation to estimate the transmitted symbols.

Abstract: At the transmitter side, carrier waves are modulated according to an input signal for producing relevant signal points in a signal space diagram. The input signal is divided into, two, first and second, data streams. The signal points are divided into signal point groups to which data of the first data stream are assigned. Also, data of the second data stream are assigned to the signal points of each signal point group. A difference in the transmission error rate between first and second data streams is developed by shifting the signal points to other positions in the space diagram. At the receiver side, the first and/or second data streams can be reconstructed from a received signal. In TV broadcast service, a TV signal is divided by a transmitter into, low and high, frequency band components which are designated as a first and a second data stream respectively.

Abstract: A digital signal gating method and apparatus of a preprocessor in a detection system wherein the detection system includes a central processing unit, a main memory and a receiver, whereby the apparatus and method bifurcate received digital signals, delays them along a first path while subjecting the digital signals along a second path to detection, delay, and thresholding and thereby generates a gating signal from the second path so that digital signals of the first path, including pre-threshold amplitudes, may be recorded.

Abstract: A method and an apparatus relating to a fine frequency synchronization compensating for a carrier frequency deviation from an oscillator frequency in a multi-carrier demodulation system of the type capable of carrying out a differential phase decoding of multi-carrier modulated signals, the signals comprising a plurality of symbols, each symbol being defined by phase differences between simultaneous carriers having different frequencies. A phase difference between phases of the same carrier in different symbols is determined. Thereafter, a frequency offset is determined by eliminating phase shift uncertainties related to the transmitted information from the phase difference making use of a M-PSK decision device. Finally, a feedback correction of the carrier frequency deviation is performed based on the determined frequency offset. Alternatively, an averaged frequency offset can be determined by averaging determined frequency offsets of a plurality of carriers.

Abstract: A cellular communications system may include one or more cellular base stations and a plurality of mobile cellular communications devices for communicating therewith. More particularly, the cellular base station and the mobile cellular communications devices may each include an encoder for generating an information signal. Furthermore, a modulator may generate a modulated waveform based upon the information signal, a carrier signal having a frequency and phase associated therewith, and at least one carrier phase reference symbol. The modulator may also include an offset circuit so that the modulated waveform includes a carrier frequency indicator. A transmitter may also be included for transmitting the modulated waveform to the desired cellular base station or mobile cellular communications device.

Abstract: To transmit information with the aid of a transmit signal exhibiting a number of frequency-specific subcarriers from a first unit to a second unit via a transmission medium, the frequency-selective transmission characteristics of the transmission medium are determined in the first unit and then the subcarriers of the transmit signal are adapted to the transmission characteristics determined. All subcarriers of the transmit signal can be advantageously modulated with the same number of modulation levels as a result of which maximum utilization of the transmission resources of the transmission medium is achieved.

Abstract: A phase tracking circuit for use in a receiver having a raw in-phase (I) signal and a raw quadrature (Q) signal, where the raw I and Q signals have M discrete signal levels defining an M×M constellation. The phase tracking circuit corrects a phase error rotation angle ? associated with the M×M constellation.

Abstract: A method for slewing a bandwidth characteristic of a digital filter within a range between a first bandwidth characteristic and a second bandwidth characteristic. The digital filter includes a plurality of cascaded filter sections and each of the sections has respective coefficients. The method establishes a polynomial having an order greater than or equal to two for modeling a changing value of one of the coefficients at the bandwidth characteristics within the range. An index value is determined for identifying a desired bandwidth characteristic within the range. The index value is input into the polynomial to obtain a corresponding coefficient value for the one coefficient. The coefficient value is then loaded into a respective filter section.

Abstract: One example of symbol or bit error probability estimation in a communication system using soft decision information determines soft decision metric(s) for each symbol that is received over a communication channel and employs the soft decision metric(s) to obtain an estimate of symbol or bit error probability.

Abstract: The performance of forward error correction decoders for digital communication systems can be improved if soft information relating the reliability of the value representing the demodulated signal is provided to the decoder with a value for the signal. On the other hand, soft information increases the quantity of information that must be processed, increasing the cost and complexity of the decoder.

Abstract: This invention is regarding a frequency shifting circuit suitable for a digital demodulator in a multi-carrier communications system. After converting analog signal vectors to the input signal vectors according to a predetermined sampling clock, control data is generated from a frequency difference between sub-carrier bands and center carrier band. A signal vector rotator is provided corresponding to each of the sub-carrier bands and rotates the input signal vectors on the I-Q plane by an angle determined depending on corresponding control data to shift the sub-carrier bands of the input signal vectors to the center carrier band. A band-pass filter passes an output signal vector of the center carrier band.

Abstract: A receiver section recovers the in-phase and quadrature components of a linear modulated data signal. The in-phase signal is sampled and quantized producing an in-phase sample stream, and the quadrature phase signal is sampled and quantized producing a quadrature sample stream. The in-phase sample stream and the quadrature sample stream are both over-sampled at a rate of N times a symbol rate of the data signal. A decimation section filters the quantized in-phase sample stream and the quantized quadrature sample stream to produce a reduced in-phase sample stream and a reduced quadrature sample stream at a rate of M times the symbol rate, wherein M is less than or equal to N.

Abstract: A method for weighting orthogonal frequency division multiplexed soft symbols is provided, including the steps of receiving a plurality of sub-carriers modulated by digital information and filtering the sub-carriers to produce complex soft decision outputs. The magnitudes of the soft decision outputs are used to creating a first sequence of data. The differences between successive samples in the first sequence are used to create a second sequence of data. The first and second sequences are used to determine a plurality of weights and the weights are applied to the complex soft decision outputs. A receiver which incorporates the method is also disclosed.

Abstract: A method for simultaneously receiving and processing multiple channels of data at independent rates which share a same frequency spectrum begins with receiving a multichannel data communication signal having multiple data channels at independent data rates on the same frequency spectrum. Next, selected channels of data of the received signal are separated and the data rate for each channel is identified. Then each separated channel of the received signal is decoded at an assigned data rate using a common decoding memory. Lastly, each separated channel is directed to a different decoding means and each decoding means is assigned a data rate responsive to the identification of data rates when the channels were separated.

Abstract: A apparatus and method for estimating a sequence of transmitted quadrature amplitude modulation (QAM)-modulated signals and space-time block coded signals using an optimal expectation-maximization (EM)-based iterative estimation algorithm in a multiple-input and multiple-output (MIMO)-orthogonal frequency division multiplexing (OFDM) mobile communication system. An initial sequence estimation value is produced on the basis of a predetermined initial value using a pilot sub-carrier contained in each of OFDM signals received by a receiving side. A normalized value of a received signal on a channel-by-channel basis is produced by a predetermined equation using orthogonality between the OFDM signals received by the receiving side. At least one subsequent sequence estimation value is produced using the initial sequence estimation value and the normalized value of the received signal on the channel-by-channel basis.

Abstract: A system analyzer may generate an estimated frequency response of a device, system, communication medium, or combination thereof by utilizing a stimulus signal that is robust against IQ modulator impairments. A stimulus generator may be used to generate a plurality of discrete tones according to a frequency spacing and a frequency offset. The frequency spacing and the frequency offset cause spectrally inverted spurs (generated by impairments of the IQ modulator) to occur at frequencies other than frequencies of said modulated signal that are associated with said plurality of discrete tones. Additionally, by implementing a Discrete Fourier Transform (DFT) to possess a frequency resolution equal to the frequency offset, there is no leakage of power associated with the spectrally inverted spurs into frequency bins of the DFT associated with the desired frequency components. Likewise, leakage between the desired frequency components and leakage associated with the local oscillator may be avoided.

Abstract: A method for transmitting and receiving an uncompressed HDTV signal over a wireless RF link includes steps of: providing a clock signal synchronized to the uncompressed HDTV signal; and providing a stream of regenerated data from the uncompressed HDTV signal, with the clock signal synchronized to the stream of regenerated data. The clock signal is then used for demultiplexing the stream of regenerated data into an I data stream and a Q data stream. The method further includes steps of: modulating a carrier with the I data stream and the Q data stream; transmitting the carrier over the wireless RF link; demodulating the carrier so that the I data stream and the Q data stream are recovered; multiplexing the I data stream and the Q data stream into a single stream of HDTV data; and recovering the uncompressed HDTV signal from the single stream of HDTV data.

Abstract: A single, common correlation filter (CF) core is provided in a wireless system using CDMA. A plurality of channels with different data rates are provided in the wireless system. The channels provided in the wireless system include the access channel, the maintenance channel, and the traffic channel in which information (e.g., pilot or data symbols or both) is transmitted at the tier 1, tier 2 and tier 3 rates. The data rate for transmitting the information is programmable by digital signal processor (DSP). A user-unique code, such as a PN code, is applied to the information being transmitted in the channels of the wireless system. The information is QPSK modulated and transmitted in any one of the channels at any data rate. The transmitted information is correlated at the smallest data rate (i.e., the tier 1 rate) in the correlation filter (CF) of the wireless system by time multiplexing delayed versions of the PN code to the correlation filter core.

Abstract: A QPSK modulation scheme uses a data spreading mechanism to rob a relatively limited portion of available transmitter power, and inject into the QPSK waveform a prescribed amount of carrier signal power, through which detection and non-regenerative extraction of the carrier at the receiver may be achieved without incurring a signal-to-noise degradation penalty. In addition, the injected carrier-based modulation scheme of the invention may employ high performance forward error correction coding, to significantly reduce the signal power required for achieving a very low energy per bit-to-noise density ratio (Eb/N0)—on the order of one to zero dB.

Abstract: At the transmitter side, carrier waves are modulated according to an input signal for producing relevant signal points in a signal space diagram. The input signal is divided into, two, first and second, data streams. The signal points are divided into signal point groups to which data of the first data stream are assigned. Also, data of the second data stream are assigned to the signal points of each signal point group. A difference in the transmission error rate between first and second data streams is developed by shifting the signal points to other positions in the space diagram expressed at least in the polar coordinate system. At the receiver side, the first and/or second data streams can be reconstructed from a received signal. In TV broadcast service, a TV signal is divided by a transmitter into low and high frequency band components which are designated as first and second data streams respectively.