Abstract: A system and method in a communication device (10) uses timing tracking to correct timing drifting due to the difference in frequency of a transmitter clock and a receiver clock. With the timing tracking, correlation values of three consecutive samples are calculated using the receive signal and the recovered symbols and then summed. A timing signal, (nk, frack) is updated based upon a metric calculated from a previous correlation value, R−1, present correlation value (R0) and a next con-elation value (R+1). Adjustment of timing signal is based on the relative location with respect to the current timing of a peak of a second order polynomial curve formed by the first correlation value R−1, the second correlation value Ro and the third correlation value R+1.

Abstract: A receiver (200) receives (402) a first signal including a sync portion (308) having a carrier acquisition segment (302) and a timing synchronization pattern (304), and a processing system (216) of the receiver calculates (404) a first plurality of squared magnitude Fourier transforms at a first plurality of frequencies on the carrier acquisition segment. The processing system derives (406) an initial carrier frequency error estimate by locating a peak in the first plurality of squared magnitude Fourier transforms, and corrects (408) the sync portion according to the initial carrier frequency error estimate, thereby producing a carrier-corrected sync portion. The processing system then removes (410) the timing synchronization pattern from the carrier-corrected sync portion, thereby producing a second signal having a residual carrier error.

Abstract: The present invention provides an electrical contactor for connecting and disconnecting an electrical power source to an electrical device wherein the electrical power source is electrically connected to a line terminal having a line terminal electrical contact and the electrical device is electrically connected to a load terminal electrical contact. The electrical contactor contains a plurality of electrical contacts which contact the line and load terminal electrical contacts.

Abstract: An adaptive Reed-Solomon(RS) decoder (207) and analogous methods arranged and constructed to decode a RS(n,k) encoded symbol stream, including; a code register (211), coupled to the symbol stream, for storing a received code word including code symbols, an index register (213) for storing a location information corresponding to each of a portion of the code symbols, a processor (215), coupled to the code register (211) and the index register (213), for performing soft decision decoding using an error parameter (217) and an erasure parameter (219) to provide corrected data (215) when the decoding is successful and to provide a failure indication (221) when decoding is unsuccessful, and a controller (223), coupled to the processor (215), for providing the error parameter and the erasure parameter and for adjusting the error parameter and the erasure parameter when the processor provides the failure indication.

Abstract: A receiver architecture includes a selectivity filter (206) for selectively passing a wanted channel and rejecting unwanted channels. The selectivity filter has a filter BT of about one-half the BT of the transmitter filter. A discriminator (208) is coupled to the selectivity filter for converting received symbols from the frequency domain to the time domain symbols. A symbol recovery processor (210) is coupled to the discriminator for recovering the symbols through a two-state maximum likelihood sequence estimation (MLSE) technique in which templates are optimized with a BT substantially less than the BT of the transmitter filter.

Abstract: A signal analyzer (303) and method thereof using short-time signal analysis, preferably recursive, to obtain a time variant feature from a signal, the signal analyzer including a signal sampler (401) with an input register (403) for storing a sequence of samples of the signal, a multiplier (405) for weighting in accordance with, alternatively, a half-sine, cosine, 2nd order complex pole, or 3rd order complex pole function the sequence of samples to provide weighted samples of the signal, and a combiner (407) for combining the weighted samples to provide a signal feature estimate, such as a signal average or frequency dependent energy estimate, for the signal.

Abstract: A signal processor and method therein that is arranged and constructed to recover a sequence of symbols from a received signal is discussed. The processor includes a symbol selector for selecting a symbol based on the received signal over a time period including previous symbol periods, said symbol period, and a number of additional symbol periods, where said number of additional symbol periods depends on the inter symbol interference associated with the received signal. The processor utilizes an MLSE approach that is adapted to be especially calculation efficient.

Abstract: The present invention provides a current limiting circuit breaker having a plurality of current responsive devices for opening a pair of contacts upon short circuit conditions. One such device is a conventional magnetic tripping mechanism. The other device utilizes an insulating object driven by a magnetic force caused by the short circuit current. Upon opening of the contacts with the use of the insulating object, let-through current flows through a secondary contact, positioned on the insulating object, to a positive temperature coefficient resistivity element which limits the current and arcing in the contacts. In an alternative embodiment, at least one steel component is added to increase the magnetic force, thereby providing a greater force on the insulating object. An insulation component is also added to further suppress any arc generated between the contacts when going from a closed state to an open state.

Abstract: A processor (306) is assigned a predetermined synchronization signal for use in communicating in a wireless communication system (100) The processor calculates (402) a total energy of the predetermined synchronization signal. A receiver front end (302) coupled to the processor receives (404) a signal which may include the predetermined synchronization signal, and calculates (406) a plurality of cross-correlation values between the received signal and the predetermined synchronization signal to locate a correlation peak. The processor also calculates (408) a plurality of detection metrics as a function of the plurality of cross-correlation values, the received signal, and the predetermined synchronization signal.

Abstract: The present invention provides a current limiting circuit breaker having a current responsive device for opening a pair of contacts or switch upon short circuit conditions. The current responsive device utilizes an insulating object driven by a magnetic force caused by a short circuit current. Upon opening of the contacts with the use of the insulating object, let-through current flows through a secondary contact, positioned on the insulating object, to a positive temperature coefficient resistivity element which limits the current and arcing in the contacts. The PTC elements could be pure metallic materials such as pure tungsten, pure iron, etc. Conductive polymer and ceramic PTC materials could also be used for some specific applications. The present invention also provides a method of electrically connecting a drive plate and a line terminal on the current limiting circuit breaker.

Abstract: The present invention provides a current limiting circuit breaker having a current responsive device for opening a pair of contacts or switch upon short circuit conditions. The current responsive device utilizes an insulating object driven by a magnetic force caused by a short circuit current. Upon opening of the contacts with the use of the insulating object, let-through current flows through a secondary contact, positioned on the insulating object, to a positive temperature coefficient resistivity element which limits the current and arcing in the contacts. The PTC elements could be pure metallic materials such as pure tungsten, pure iron, etc. Conductive polymer and ceramic PTC materials could also be used for some specific applications. The present invention also provides a method of electrically connecting a drive plate and a line terminal on the current limiting circuit breaker.

Abstract: A receiver architecture for receiving an FSK signal having a predetermined number of modulation levels includes a selectivity filter (206) for selectively passing a wanted channel and rejecting unwanted channels. The selectivity filter has a filter bandwidth of about one-half the bandwidth of a pre-modulation filter in a transmitter sending the FSK signal. A discriminator (208) is coupled to the selectivity filter for demodulating the signal. A symbol recovery processor (210) is coupled to the discriminator for recovering the symbols through a maximum likelihood sequence estimation (MLSE) technique utilizing N states for each symbol time, wherein N equals the predetermined number of modulation levels, and wherein templates used in the MLSE for symbol transitions are optimized with a bandwidth substantially less than the bandwidth of the pre-modulation filter.

Abstract: A processing system (216) selects (1004) a portion (702-706) of a received signal including an evaluation symbol (702), along with a preceding symbol (704) received immediately before the evaluation symbol, and a following symbol (706) received immediately after the evaluation symbol; and prefixes (1006) to the portion of the received signal a previously estimated symbol (708) received immediately before the portion, thereby producing an evaluation portion (712, 904). The processing system then compares (1008) the evaluation portion with templates equal in length to the evaluation portion and including different combinations of trial symbols and the at least one previously estimated symbol, prefixed to the trial symbols; and estimates (1010) the evaluation symbol to be equal to a trial symbol in one of the templates having a highest correlation with the evaluation portion, the trial symbol having a position matching that of the evaluation symbol in the evaluation portion.

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.