Abstract: A demodulator (604) demodulates (802) a block of symbols of a signal through a single-symbol matched-filter technique, thereby generating a first set of data; and demodulates (804) the block of symbols through a multi-symbol matched-filter technique, thereby generating a second set of data. The demodulator obtains (806-810) a measurement of a characteristic of the signal, and chooses (814-816) one of the first and second sets of data for output, based upon the measurement.

Abstract: A processor (202) delays (906) a baseband digital signal by a symbol duration, thereby generating a delayed baseband digital signal. The processor adds (908) the baseband digital signal to the delayed baseband digital signal, thereby generating a summed signal; and divides (910) the summed signal by two, thereby generating a threshold signal. The processor also delays (912) the baseband digital signal by one-half the symbol duration, thereby generating a half-delayed signal; and subtracts (914) the threshold signal from the half-delayed signal, thereby generating a candidate signal. In addition, the processor searches (916) for a zero crossing in the candidate signal, and generates (918) a pulse in response to finding the zero crossing.

Abstract: In a zero intermediate frequency (ZIF) receiver (300) a desired signal is detected (902) and downmixed (924) to baseband, off-centered by an amount determined by at least one of (a) whether (906) pilot symbols are present in the desired signal, and (b) signal levels (908) of the desired signal and adjacent channel signals.

Abstract: At least two non-collocated transmitters (116) transmit (1604) a synchronization signal such that it includes at least three predetermined tone frequencies. A receiver (122) receives (1606) the synchronization signal, and separates (1608) the synchronization signal into a plurality of segments (404). The receiver then calculates (1610) segment Fourier transform values corresponding to the at least three predetermined tone frequencies, for ones of the plurality of segments, thereby creating a set of segment Fourier transform values. The receiver also computes a set of segment time-of-arrival (TOA) values corresponding to the set of segment Fourier transform values. In addition, the receiver determines (1612) a set of segment weights from the set of segment Fourier transform values, and estimates (1616) the TOA of the synchronization signal from the set of segment TOA values and the set of segment weights.

Abstract: In a wireless communication system a first transmission (612, 614) is sent (802) over a first channel to a first receiver (122) that requires a transmission-free guard band (620) during a tuning period, and the first receiver accommodates a second transmission (616) sent concurrently with the first transmission on a second channel that overlaps with spectrum occupied by the guard band. During the tuning period, the system disallows the second transmission, and the first receiver adjusts (804) a pass band of a radio frequency (RF) filter (302) therein such that the pass band includes the guard band. Thereafter, the first receiver tunes (806) to the first channel. During a time other than the tuning period, the first receiver readjusts (810) the pass band of the RF filter such that the pass band excludes the guard band. After the tuning period, the system allows the second transmission to be sent (812).

Abstract: In a messaging system having a plurality of simulcasting base transmitters (104), a plurality of pseudorandom sequence generators (216) are provided (402) for the plurality of base transmitters. The plurality of pseudorandom sequence generators are arranged (403) to ensure that they generate a plurality of pseudorandom sequences having sub-sequences that are different from one another during concurrent transmissions by the plurality of base transmitters. A cancellation-affecting parameter of the plurality of base transmitters is adjusted (404, 406, 408) in accordance with the plurality of pseudorandom sequences during the simulcast transmission from the plurality of base transmitters to limit intervals of carrier cancellation.

Abstract: A radio signal is digitized and filtered to derive a digitized pilot signal (210) modulated by channel amplitude and phase distortion. A numerator and a denominator are formed for dividing the digitized radio signal (208) by the digitized pilot signal, the numerator and the denominator requiring a first predetermined number of bits per sample. The bits of the numerator and the denominator are shifted (518) by equal amounts until a highest order bit of one of the numerator and the denominator is non-zero. A second predetermined number of highest order bits of the numerator are divided (524) by the second predetermined number of highest order bits of the denominator in a divider utilizing less than the first predetermined number of bits, to generate a channel compensated radio signal (536) having a minimum number of bits that can accommodate a predetermined maximum dynamic range.

Abstract: A method and apparatus samples (902) a currently received symbol to form sampled values corresponding to sampling times, and evaluates (904) the currently received symbol to determine (906) its value. The method and apparatus recalls (908) a last previously received symbol and selects (916), from a plurality of thresholds (302), a threshold based upon the currently received symbol and the last previously received symbol. The threshold is known to be crossed consistently midway in time between the centers of two adjacent nominal symbols determined by the currently received symbol and the last previously received symbol. The sampled values are compared (920) to locate two adjacent samples, one having a first sampled value greater than the threshold and one having a second sampled value less than or equal to the threshold. A timing phase error is then computed (922, 924) from the first and second sampled values.

Abstract: A radio receiver circuit (100) is used for receiving a multi-level signal from a radio communication system. The multi-level signal includes a plurality of symbols, wherein each level is representative of a symbol of data. The receiver circuit (100) includes a demodulator circuit (106) and a digital circuit (112). The demodulator circuit (106) is used for receiving the multi-level signal and for generating baseband samples for each symbol, whereby each sample has a phase and a signal level. The digital circuit (112) is coupled to the demodulator circuit (106), and is adapted to tally, by category, occurrences of the baseband samples, whereby each category is representative of one of a plurality of phases, and one of a plurality of signal level ranges. The digital circuit (112) is further adapted to correlate the categories to at least one predetermined template, and to classify the multi-level signal according to the correlation results.

Abstract: A receiver (109) and a method therein arranged and constructed to receive a signal using a noncoherent matched filter structure including a frequency detector (205) arranged to process a first portion (602) of the signal to provide a frequency error; a timing detector (206), responsive to the frequency error, arranged to process a second portion (604) of the signal to provide a timing error; and a symbol detector (209), responsive to the frequency error and the timing error, arranged to process a symbol portion (606) of the signal to provide a detected symbol.

Abstract: A data receiver (110) for processing multiple signals includes a receiving circuit (120) for demodulating at least first and second signals and a selector (125) coupled to the receiving circuit (120) for comparing the at least first and second signals to estimated peak and valley values. The selector (125) generates error values associated with the at least first and second signals and selects a data symbol associated with one of the estimated peak and valley values based on the error values. A timing circuit (140, 150) activates the selector (125) at predetermined times, and a controller (140) coupled to the selector (125) and the timing circuit (140, 150) recovers information in accordance with the data symbol and other data symbols.