Abstract: “Reliability-related” values are assigned to received signal samples containing noise and distortion. The samples are then sent to a Viterbi decoder in order to regenerate originally transmitted messages.

Abstract: The performance of wireless devices is improved using methods and devices which comprise novel SPEED and NOISE metrics. The SPEED metric is generated from a mean value of a differential signal while the NOISE metric is generated from a variance value of a differential signal. The generation of both metrics assumes the use of a limited number of symbols used to generate the mean and variance values. One example of a signal used to generate the metrics comprises the 14 synchronization symbols which make up part of an IS-136 standard signal. The SPEED metric was discovered to comprise a value which is equal to the magnitude of the mean value of the differential signal while the NOISE metric was discovered to comprise a value which is approximately equal to twice the variance of noise in a received baseband signal, while at the same time being independent of the speed at which an object, such as a wireless device, moves.

Abstract: A phase-modulated signal such as a quadrature phase-shift-keyed (QPSK) signal in a wireless communication system is demodulated using sample timing based at least in part on frequency information generated by frequency demodulating the phase-modulated signal. The phase-modulated signal is separated into first and second portions, the first portion is phase demodulated to generate demodulated symbols, and the second portion is frequency demodulated to generate, e.g., a measure of the instantaneous frequency of the phase-modulated signal. The instantaneous frequency measure is processed to identify one or more symbol transitions, and the identified transitions are used to establish the sample timing such that proper sampling of the symbols is ensured.

Abstract: A computer implemented method and apparatus utilizing a multi-diversity synchronization technique for improving time synchronization in wireless applications, such as TDMA applications is disclosed. The multi-diversity synchronization technique utilizes cross-correlations between multiple diverse received signals to determine relative offsets between the signals. The signals are then time aligned. An absolute synchronization word location is determined using the time aligned signals and is used along with the relative offsets to determine respective synchronization word locations for each received signal in an accurate, efficient and improved manner.

Abstract: Non-intrusive monitoring and analysis of real-time facsimile transmissions is accomplished. Analog impairment measurements are made on the high speed page signal in those transmissions and protocol analysis is made on the low speed control messages in those transmissions. These measurements and analysis are a powerful tool for trouble shooting service problems afflicting facsimile transmissions. Real customer traffic can be monitored to detect circuit impairments and to evaluate service being provided. A selected incoming trunk of a central office switch is accessed and a monitoring function with respect to that trunk is established. A signal classification operation is performed, which identifies the presence of a facsimile transmission and what kind of facsimile transmission it is.

Abstract: Non-intrusive monitoring and analysis of real-time facsimile transmissions is accomplished. Analog impairment measurements are made on the high speed page signal in those transmissions and protocol analysis is made on the low speed control messages in those transmissions. These measurements and analysis are a powerful tool for trouble shooting service problems afflicting facsimile transmissions. Actual customer traffic can be monitored to detect circuit impairments and to evaluate service being provided. Customer complaints can be handled by providing them with a special phone number which may be called to provide the ability to have the facsimile transmission experiencing a problem specially directed through the facsimile analyzer and forwarded to the intended destination while it is being non-intrusively monitored by service personnel who then can quickly provide the customer with a diagnosis of the problem.

Abstract: An unknown voiceband digital data modem signal is classified as being generated by one of a plurality of possible digital data modem signal sources, e.g., CCITT V.29, CCITT V.32, CCITT V.33 or the like digital data modems. Classification is achieved by employing a blind, i.e., self-recovering, adaptive equalizer to remove effects of linear channel impairments and to generate a sequence of magnitude estimates at the symbol rate of the unknown voiceband digital data modem signal. The sequence of magnitude estimates is compared to predetermined representations of known possible voiceband digital data modem signals and the results of the comparison are used to identify the digital data modem signal source of the signal. In one example, the predetermined representations are templates of conditional density functions of magnitude estimates obtained from known voiceband digital data modem signals generated by corresponding digital data modem signal sources.

Abstract: During a training sequence, a speaker-trained speech recognizer detects and signals the speaker when vocabulary word pairs are potentially confusing to the recognizer. Each vocabulary word is converted into feature signals and then parameters representing a predetermined reference model of that word. The feature signals of a subsequent potential vocabulary word are compared against the reference model of each vocabulary word previously stored in the recognizer memory. The speaker is signaled when the potential vocabulary word is confusingly similar to one of the existing vocabulary words.

Abstract: An electronic musical instrument wherein purely digital techniques are utilized for generating the basic waveform train and also keying the waveform train so as to have the customary keying envelope with attack, sustain and decay portions. The wavetrain is a cyclically repeated series of four-term Blackman-Harris window functions, wherein there are preferably eight such functions in each series. A plurality of individual keying envelopes are generated by a piecewise linear technique, and these envelopes are assigned respectively to the waveforms in the series so that the relative amplitudes of the waveforms can change with time over the life of the tone. This results in modulating with time the harmonic content of the tone.