Abstract: A receiver front end (604) receives sequence of symbols. A processor (606) coupled to the receiver front end computes a metric corresponding to the sequence of symbols. The metric is selected from one of: (a) a recursive metric having a structure m({overscore (a)}k)=m({overscore (a)}k−1)+{circumflex over (m)}(ak−N, . . . , ak−1, ak), wherein m({overscore (a)}k−1) and m({overscore (a)}k) are the cumulative metrics for symbols up to ak−1 and ak, respectively, and {circumflex over (m)}(ak−N, . . . , ak−1, ak) is the incremental metric, a function of (N+1) symbols {ak−N, . . . , ak−1, ak}, and (b) a non-recursive metric m({overscore (a)}k) that is an arbitrary function of a set of L submetrics {z1({overscore (a)}k), z2({overscore (a)}k), . . . , zL({overscore (a)}k)} m({overscore (a)}k)=m[z1({overscore (a)}k), z2({overscore (a)}k), . . .

Abstract: A communication receiver (300) receives (404) a modulated signal, and demodulates the modulated signal to recover a timing signal (202) and a data signal (204) including data symbols. A processing system (316) of the communication receiver determines (406) a rough symbol timing from the timing signal, and forms (408) a timing-carrier search matrix by computing signal quality metrics from the data symbols as a function of predetermined trial variations of the carrier frequency about a nominal carrier frequency and as a function of predetermined trial variations of the symbol timing about the rough symbol timing. The processing system then estimates (410) the symbol timing and the carrier frequency by locating a minimum one of the plurality of signal quality metrics in the timing-carrier search matrix.

Abstract: Apparatus in a receiver (109) and analogous method for detecting or acquiring a timing reference or error for a data signal, including a receiver front end (201) for receiving a sequence of symbols, and a signal processor (218) programmed to correlate, using a recursive procedure, the sequence of symbols to a predetermined sequence of symbols to provide a correlated magnitude corresponding to a timing error (212) and then adjust a timing reference in accordance with the timing error.

Abstract: A Positive Temperature Coefficient Resistivity (PTC) element has a resistivity that increases as the temperature increases. Circuit breakers having PTC elements can achieve better overload and short circuit protection than existing products. Breakers with PTC elements can also be combined with ground fault detection circuits to activate the circuit breaker under ground fault conditions that are less severe than the overcurrent conditions that would normally activate the circuit breaker. A shunt trip assembly incorporating a PTC resistor reduces the required power rating of the clearing switch.

Abstract: A method and apparatus receives a symbol and subdivides (720) the symbol into a plurality of fragments. The method and apparatus perform (704) for the plurality of fragments a plurality of correlations with at least one possible symbol value, thereby producing a plurality of complex values corresponding to each fragment and further corresponding to the at least one possible symbol value. From the plurality of complex values a plurality of overall Fourier transforms are computed (706) across a frequency range, and a peak value in the plurality of overall Fourier transforms is located (708). The symbol is then determined (710) from the peak value.

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 signal processor arranged and constructed to provide a discrete time Fourier transform (DTFT) corresponding to a sequence of samples, including a current, preferably, last sample, of a signal, the signal processor including a recursive structure (303), coupled to the signal and operating on the sequence of samples, for providing an output (309) and a first previous output (310), the output proportional to a combination of the current sample of the signal, and the first previous output weighted by a sinusoidal function, less a second previous output (316), the sinusoidal function having an argument corresponding to an arbitrary frequency, and a combiner (330) coupled to the output and the first previous output for providing a DTFT signal proportional to a DTFT evaluated at the arbitrary frequency for the sequence of samples.

Abstract: A signal quality detector (206) and analogous method thereof for operation on a signal having at least one predetermined frequency, the detector including a symbol detector (209), coupled to the signal, for providing a maximum discrete time Fourier transform value for a time period, the maximum discrete time Fourier transform value corresponding to one of the at least one predetermined frequency, an energy detector (217) for providing an energy estimate corresponding to a energy value of the signal over the time period, and a combinatorial logic (219) for combining the maximum discrete Fourier transform value and the energy estimate to provide a signal quality estimate or signal power or noise power.