Abstract: In an example, a method comprises defining an object comprising a plurality of discrete components, each of which comprises a set of discrete formulas having a predefined order. The method initiates an evaluation of each discrete component by looping over each formula of that discrete component to produce a result set according to the predefined order by evaluating without specifying a dimensionality to produce the result set with a single row, or evaluating the formula with a specified dimensionality to produce the result set with a plurality of rows. The method displays a calculation user interface, determines that an action exists that is associated with at least one formula of at least one discrete component, displays a user-selectable element corresponding to the action, and automatically pauses computation of at least a portion of the evaluation until input selecting the user-selectable element is received.

Abstract: A voice processing method, a voice communication device, and a computer program product thereof are disclosed. The method comprises the steps of: receiving a transmitting voice signal from a receiver end communication device; determining a frequency range of the transmitting voice signal; receiving an original voice signal from a first user; processing the original voice signal to a processed voice signal, wherein the processed voice signal is generated based on the frequency range of the transmitting voice signal; and outputting the processed voice signal to the receiver end communication device.

Abstract: A system and method for processing a plurality of channels, for example audio channels, in parallel is provided. For example, a plurality of telephony channels are processed in order to detect and respond to call progress tones. The channels may be processed according to a common transform algorithm. Advantageously, a massively parallel architecture is employed, in which operations on many channels are synchronized, to achieve a high efficiency parallel processing environment. The parallel processor may be situated on a data bus, separate from a main general purpose processor, or integrated with the processor in a common board or integrated device. All, or a portion of a speech processing algorithm may also be performed in a massively parallel manner.

Abstract: A new method for processing search radar data is revealed using the mathematics of random matrix theory. During the time that the radar receiver is listening for return target echoes, the raw data stream is fed to an analog to digital converter to create a sample voltage file. This sample voltage file is processed by a digital signal processor that computes the eigenvalues of a sample covariance matrix generated for each pulse duration interval. The ratio of the largest to smallest eigenvalue is determined and compared to the system noise eigenvalue ratio. The sensitivity for detecting targets over the present state of the art is expected to be an approximate enhancement factor of one thousand, due to the detection of coherent energy instead of a transmitted waveform. The increase of detection distance for same radar cross section is expected to be an approximate 5.6 enhancement factor.

Abstract: In one aspect, a method of processing a voice signal to extract information to facilitate training a speech synthesis model is provided. The method comprises acts of detecting a plurality of candidate features in the voice signal, performing at least one comparison between one or more combinations of the plurality of candidate features and the voice signal, and selecting a set of features from the plurality of candidate features based, at least in part, on the at least one comparison. In another aspect, the method is performed by executing a program encoded on a computer readable medium. In another aspect, a speech synthesis model is provided by, at least in part, performing the method.

Abstract: In one aspect, a method of processing a voice signal to extract information to facilitate training a speech synthesis model is provided. The method comprises acts of detecting a plurality of candidate features in the voice signal, performing at least one comparison between one or more combinations of the plurality of candidate features and the voice signal, and selecting a set of features from the plurality of candidate features based, at least in part, on the at least one comparison. In another aspect, the method is performed by executing a program encoded on a computer readable medium. In another aspect, a speech synthesis model is provided by, at least in part, performing the method.

Abstract: A method for decoding a DTMF tone which includes collecting the width of serial signals by measuring the time interval between zero-crossing points within a predetermined time; counting within the predetermined time the number of signal zero-crossing points; performing interpolation on the data produced by the collecting and counting steps with a Fourier transform; identifying a first frequency that has the strongest magnitude from the resulting data; and calculating the lower frequency of the tone being decoded by subtracting the first frequency from the average frequency of the digitized signal.

Abstract: Disclosed is an integrated tone detection processor for discriminating between tone and voice signals and determining the tones. The tone detection processor performs Automatic Gain Control (AGC) to normalize the power of the tone or voice signal. Further, the energy of the tone or voice signals are determined at specific frequencies utilizing a Goertzel Filter process. The tone detection processor determines whether or not a tone is present, and if a tone exists, determines the type of tone. Based upon determining the two maximum energy levels of the Goertzel filtered tone, whether the tone is a single tone, dual tone, silence, or other (e.g. speech) can be discriminated. The tone can then be identified by a user-defined dictionary of tones. Based upon various ON and OFF cadence checks in combination with the use of TONE ON and TONE OFF counters, tones can be declared.

Abstract: A method of detecting frequency errors exceeding a predetermined limit in a sampled signal includes the step of determining a peak amplitude of the signal at a tone frequency for a first frame of samples of the sampled signals using a filter having a first amplitude versus frequency response. A peak amplitude of signal at the tone frequency is determined for a second frame of samples of the sampled signal using a filter having a second amplitude versus frequency response. A ratio between the peak amplitude of the first frame and the peak amplitude of the second frame is calculated and compared against a threshold to detect frequency errors exceeding the predetermined limit. Among other things, this method decouples the frequency error detection problem from the twist factor estimation problem.

Abstract: System and methods for determining an optimized transmit spectra (spectral distributions of transmission power) for a set of communications channels that experience cross-talk among themselves and for transmitting data on the channels. The transmit spectra are preferably constructed so that largely contiguous frequency bands are allocated to each signaling direction (upstream/downstream) on each communications channel and/or to each channel in the set of channels. In one embodiment, each communications channel is restricted to a maximum time-averaged power. The method preferably includes steps of determining the channel transfer functions of the communications channel, determining interference characteristics of the channels, calculating substantially optimal transmit spectra for the communications channels, and redistributing the frequency bins so that they are contiguously grouped in each transmit spectra. The contiguous groupings allow wider frequency bands for signaling in the channel.

Abstract: A signal detector includes a transform unit and a post processing test unit. The transform unit is adapted to a transform unit adapted to receive at least first and second frames of input samples, determine a first plurality of energy values for the first frame based on a first set of transform coefficients, and determine a second plurality of energy values for the second frame based on a second set of transform coefficients. The post processing test unit is adapted to identify at least one target frequency based on the first plurality of energy values. The second set of transform coefficients is based on the target frequency, and the post processing unit is adapted to determine the presence of a first signal in the input samples based on the second plurality of energy values. A method for detecting a signal is provided. A first frame of input samples is received. A first set of transform coefficients is determined based on a first plurality of frequencies.

Abstract: A signal detector includes a transform unit, a gain control unit, and an energy level threshold unit. The transform unit is adapted to receive a plurality of input samples and calculate a first plurality of delay values based on the input samples. Each delay value is based on at least one previous delay value and a current input sample. The transform unit is adapted to calculate a first energy value based on at least a subset of the first plurality of delay values. The gain control unit is adapted to determine if a selected delay value of the first plurality of delay values exceeds a predetermined threshold and scale the selected delay value, the at least one previous delay value used to calculate the selected delay value, and subsequent input samples received after the current input sample by a first amount in response to the selected delay value exceeding the predetermined threshold.

Abstract: A method for inhibiting the use of dual tones over an established voice channel of a telecommunications network. The method inhibits a call tone by removing at least one frequency selected from a group of frequencies used for in-band signaling. The method may also determine a time for inhibiting the call tone.

Abstract: A voice encoding device according to the present invention includes an encoder having a first quantizing block suitable for voice encoding and a second quantizing block suitable for non-voice encoding and compressively encoding input signals, a voice/non-voice signal identification unit for identifying whether an signal input to the encoder is a voice signal or a non-voice signal and outputting a determination result, and a multiplexer portion for multiplexing respective outputs from the first quantizing block and the second quantizing block in order to output to a transmission path. In this case, the encoder has a selector for selecting either one of the first quantizing block or the second quantizing in accordance with the determination result from the voice/non-voice signal identification unit, and the first quantizing block and the second quantizing block compressively encode signals by using a same quantization table.

Abstract: Detection of alerting or other tone signals in a composite signal are reliably detected with an improved false tone detect suppression technique which employs the use of a moving window analysis on a subset of frequencies detected within an underlying speech signal performed during each of a plurality of data frames. The composite signal is transformed during each data frame using a discrete Fourier transform comprising the so-called Goertzel Algorithm. All of the Goertzels relating to the tone detection are analyzed during each data frame, but only a subset of the Goertzels relating to the sweeping harmonic analysis of the underlying speech signal are analyzed during any particular data frame.

Abstract: In a telecommunication system having a network switch capable of independently controlling inbound and outbound call legs, a system for, and method of, redirecting in-band control of signaling pertaining to a call placed by a calling party and a system for providing automatic call completion from the calling party to a called party. The control redirecting system includes: (1) call control circuitry, associated with the network switch, for routing the call from the calling party to another party through the network switch, the call thereby having an inbound leg from the calling party to the network switch and an outbound leg from the network switch to the other party and (2) call control redirection circuitry for treating the outbound leg of the call as a second inbound leg from the other party to the network switch and monitoring in-band control signals received from the other party via the second inbound leg.

Abstract: A touch-tone receiver (TTR) simulator is disclosed to analyze DTMF signals and facilitate the investigation of call failure problems. The TTR simulator captures DTMF data received by a private branch exchange (PBX) switch and utilizes the instruction set of the TTR being simulated to process the received DTMF signals on the simulated TTR. Diagnostic tools allow step-by-step tracing and recording of the instructions performed by the simulator. The TTR simulator allows the underlying cause of a call failure problem due to DTMF signals to be identified. Results of digit interpretation can be compared to expected results.

Abstract: Apparatus and methods for adaptively, reliably, and accurately measuring the frequency of an alerting or other signaling tone. A tone detector measures the frequency of a tone (continuous or pulsed) with a high degree of accuracy (e.g., to within 1 part in 10,000). Two lower order or smaller DFTs measure the energy level in two separate but intersecting frequency ranges. A simple ratio is determined from the relative energy measured from discrete Fourier transforms relating to each of the two separate frequency ranges, and an actual measured frequency is determined.

Abstract: In a telecommunication system having a network switch capable of independently controlling inbound and outbound call legs, a system for, and method of, redirecting in-band control of signaling pertaining to a call placed by a calling party and a system for providing automatic call completion from the calling party to a called party. The control redirecting system includes: (1) call control circuitry, associated with the network switch, for routing the call from the calling party to another party through the network switch, the call thereby having an inbound leg from the calling party to the network switch and an outbound leg from the network switch to the other party and (2) call control redirection circuitry for treating the outbound leg of the call as a second inbound leg from the other party to the network switch and monitoring in-band control signals received from the other party via the second inbound leg.

Abstract: In a transmission system, a tone is transmitted by a transmitter to a receiver via a transmission channel. In the receiver, a tone detector is used to detect the presence of a signalling tone. In order to improve a reliability of the tone detector when the arrival of the signalling tone is unknown, a number of correlators having mutually displaced measuring periods are used. More than two correlators are used in order to reduce the measuring period, also resulting in an improved reliability of the tone detection.

Abstract: In a transmission system, a signalling tone is transmitted by a transmitter to a receiver via a transmission channel. In the receiver, a tone detector detects the presence of a signalling tone. In order to improve a reliability of the tone detector, a number of correlating elements which determine a correlation value between an input signal and a reference signal are used. Absolute output signals of the correlating elements are added by an adder to derive a combined correlation signal to be used for detection.

Abstract: An improved dual tone multifrequency (DTMF) or multitone signal detector which more efficiently detects DTMF signals. For each received frame, the present invention initially performs only a portion of the Goertzel DFT algorithm for each of the possible tone frequencies and then analyzes the interim accumulated energies. The DTMF detector then selects one or more frequencies from each of the tone groups which have the largest energy values, and the detector only completes calculation of the Goertzel DFT algorithm on those selected one or more frequencies. In other words, the DTMF detector discontinues calculation of the Goertzel DFT algorithm on one or more frequencies which have low accumulated interim energies. This reduces the computational requirements and provides improved performance.

Abstract: A system for detecting the presence, in an audio channel which may contain voice signals, of a tone at a frequency selectable from among a plurality of selectable frequencies. A bandpass filter receives the audio input; its center frequency is selectable in response to a control signal. A first detector circuit provides from the output of the bandpass filter an output signal when a tone containing substantial energy at about said center frequency is input to the filter. A band-stop filter having the same center frequency as the bandpass filter also receives the input audio; a second detector circuit demodulates and thresholds the band-stop filter output.

Abstract: An improved dual tone multifrequency (DTMF) or multitone signal detector which more efficiently and reliably detects DTMF signals. The present invention performs twist computations only when the signal has become stable, thus achieving more accuracy and reliability. The DTMF detector receives a plurality of digital samples of a received signal and calculates energy values for each of the plurality of different uncorrelated frequencies. The DSP then determines maximum values of the energy values for each of the two or more frequency groups, referred to as M(1) and M(2), to detect the plurality of tones in the received signal. The DTMF detector then performs improved twist computation and thresholding. The DTMF detector first determines if the M(1) and M(2) values of the respective frame being examined have the same indices.

Abstract: A telephone exchange enables subscribers to use voice dialing more easily with existing telephone systems. The voice dialing does not require special input operations or preregistration of called parties. Rather, a subscriber can make a telephone call easily without having to perform multiple operations. The telephone exchange includes structure for discriminating dial pulse information, push-button tone information, and spoken information so that one or more of these types of information can be input by a caller to achieve connection to the called party.

Abstract: In a voice processing system, a voice detection algorithm is disclosed wherein the sensitivity is adjusted based upon whether or not tones (e.g.; DTMF) are presently being received. In an additional embodiment, the adjustment is made only when the voice processing system is in a predetermined mode.

Abstract: A method for detecting the presence of voice, single tone and dual tone signals compares a ratio r which equals the square of the maximum value of the received signal (A max) during a sampling period divided by a measure E of the energy to three different thresholds. If r is less than the first threshold (3), a single tone is indicated. If it is greater than the first but less than the second, the received signal level is compared to the third threshold (-43 dB) and receipt of a voice signal is indicted if the level of the received signal exceeds this threshold.

Abstract: This tone detector which is suited for dual tone multifrequency (DTMF) digit detection, separates the pairs of tones into a low frequency and high frequency group in which the other frequency group is attenuated by filtering. The amplitude of the low and high frequency groups serve as separate variable threshold reference signals. Individual tones are bandpass filtered with their corresponding outputs converted into an amplitude signal. The amplitude of the individually bandpass filtered tone signals are compared against the corresponding low or high frequency variable threshold signal for a determination of whether a tone is present. Preferably, additional validation steps are applied to the preliminary tone decisions to provide improved digit detection accuracy, especially in the presence of other signals such as speech.

Abstract: An improved dual tone multifrequency (DTMF) or multitone signal detector which uses both static and dynamic thresholding techniques to provide an increased functional dynamic range, improved speech immunity for improved detection and reduced error, and simplified signal to noise ratio control. The DTMF detector receives signals from the transmission media, calculates energy values for the different frequencies, and then determines maximum values of the energy values for each of the frequency groups, referred to as M(1) and M(2). The DTMF detector then performs both static and dynamic thresholding according to the present invention to ensure valid tone detection. The static thresholding compares each of the M(1) and M(2) values with a static threshold value to ensure that the maximum energy values have a minimum energy to warrant detection.

Abstract: DC level control for an electronic telephone line card which filters the DC component from the input audio signal, determines the gain setting of the transmit path, develops a DC adjust voltage opposite to that of the DC shift component and subtracts the DC adjust voltage to the input voltage to cancel the DC shift component. A quantized, discontinuous feedback path is implemented to respond only to DC shifts so the AC operation remains substantially unaffected. Such discontinuous feedback eliminates stability and impedance matching problems introduced with continuous feedback solutions. A DC control circuit according to the present invention includes a low pass filter for detecting DC shifts, a quantizer for asserting an incremental signal, a threshold detector for activating adjustment functions, and an accumulator for developing the DC adjust voltage by incremental steps.

Abstract: A DTMF digit detecting method and apparatus includes signal state identifier (32) for identifying whether the received signal is in a DTMF-digit-detect state, a no-detect high-energy state, or a no-detect low-energy state, digit candidate identification processor (34) for identifying a digit candidate when the presence of a state other than the no-detect low-energy state is detected following a detection of the presence of the no-detect low-energy state for a first predetermined period of time, digit identifier (32) for identifying a DTMF digit corresponding to a sample group in a DTMF-digit-detect state, and valid digit identifier (34) for identifying a valid DTMF digit when at least a first predetermined number of sample groups are all in the DTMF-digit-detect state or in an allowable combination of states.

Abstract: A method for detecting the presence of voice, single tone and dual tone signals compares a ratio r which equals the square of the maximum value of the received signal (A max) during a sampling period divided by a measure E of the energy to three different thresholds. If r is less than the first threshold (3) a single tone is indicated. If it is greater than the first but less than the second (5.2) a dual tone is indicated. If it is greater than the second, the received signal level is compared to the third threshold (-43 dB) and receipt of a voice signal is indicated if the level of the received signal exceeds this threshold.

Abstract: A method and apparatus for detecting a dual tone alerting signal in the presence of speech for the purpose of initiating transfer of special service information on a telephone line is described. The apparatus includes two channels for separately detecting each tone. Each channel includes means for comparing the signaling energy around one of the tones with the energy in a selected weighted guard band portion of the voiceband. Based on this comparison, a determination is made whether a tone is or is not present. A pulse signal formed from the coincidences of tone detection in each channel is used by timing circuitry to determine whether the dual tone alerting signal is actually present or whether speech energy caused both tones to be erroneously detected (talkoff). Characteristics of this pulse signal are analyzed to determine whether an alerting signal is present.

Abstract: A method for detecting the presence of single tone and dual tone signals compares a ratio r which equals the square of the maximum value of the received signal (A max) during a sampling period divided by a measure E of the energy to three different thresholds. If r is less than the first threshold (3) a single tone is indicated. If it is greater than the first but less than the second (5.2) a dual tone is indicated. When a single tone is indicated the received signal is subjected to a second order autoregressive process to determine the frequency of the single tone. If a dual tone is indicated the received signal is subjected to a fourth order autoregressive process to determine the frequencies of the dual tones.

Abstract: A technique for improved DTMF detection utilizes a speech detector, either alone or in combination with other information from a voice processing arrangement, to adjust the sensitivity of the DTMF detector. The DTMF detector is turned completely off when the voice processing application is in the record mode, and when speech is detected.

Abstract: A method of improving the sensitivity and speech immunity of a receiver in conjunction with DTMF-reception is disclosed. The number of zero-crossings of the input signal are counted during one of a number of measuring intervals in real time at frequencies which occur in the low frequency group and the high frequency group of a DTMF-signal. At the end of each of the measuring intervals, the number of zero-crossings in a current measuring interval is compared for each frequency group, with a corresponding number of zero crossing in a number of nearest preceding measuring intervals, and the magnitude of any difference is established. The input signal is treated as a DTMF-signal when the difference is at most equal to a permitted limit value.

Abstract: A substantially-universal detector (FIG. 2) of far-end call disconnect-indicative tones detects the foreseeable forms of tone-based signalling of remote-end call disconnect that are likely to be employed anywhere in the world, without reconfiguration or reprogramming for different tones or countries. Implemented in the digital signal processor (DSP 30) of port circuits (14, 20) of switching systems (11) or adjunct processors (12), the detector determines parameters (204) of signals carried by the call to the near end and uses them, along with already-present linear predictive coding (LPC) predictor coefficients (202) and indications of energy (203) in the signals, in a multivariate classification (230) of call progress tones from other tones. When presence of any call progress tones is thus detected substantially without interruption for a predetermined minimum time in the received signals, the call is considered (240) to have been disconnected at the far end.

Abstract: In a preferred embodiment, a method of automating configuration of a voice processing system including automating telephone tone parameter determination, including the automated functions of: generating a first telephone line tone; scanning the first telephone line tone for frequency parameters and cadence parameters; arranging the frequency and cadence parameters in a tone definition block structure; and storing the tone definition block structure into memory of the voice processing system for future use in recognizing the first telephone line tone.

Abstract: A method of dual-tone multifrequency (DTMF) detection which decimates and adaptively filters an input signal is provided to efficiently detect a presence of a DTMF signal. The input signal is provided to a half-band filter (14) to be decimated in frequency in accordance with Nyquist's theory. A decimated input signal is subsequently processed to form a low frequency component signal and a high frequency component signal. The low frequency component signal is again decimated by a decimator (24). The decimated low frequency component signal and the high frequency component signal are each filtered by an adaptive fir filter (22, 26) to provide a first and a second frequency parameter and a first and a second gain factor, respectively. The first and second frequency parameters and the first and second gain factors are then tested by a tone identifier (28) to determine if the input signal includes a valid DTMF signal.

Abstract: A method of operating a digital signal processor to detect DTMF tones in a digital voice telephone system in which the digitally encoded signals appearing on the telephone channel are decimated to compress the spectrum to be monitored for the appearance of call signalling tones. The signals received in a decimated block are "correlated" or convolved with one another on a forward and backward time-shifted basis and each forward and backward correlation product is summed to form the elements of a 5.times.5 modified covariance matrix. The modified covariance matrix exhibits the desirable property that its eigenvectors will be symmetric. Since all eigenvectors of the modified covariance matrix are orthogonal and the eigenvectors associated with the signal span the signal subspace, the signal subspace is orthogonal to the eigenvector associated with the noise. The dot product of the noise eigenvector with the signal subspace is set to zero.

Abstract: A process for determining the presence of either speech or one of a plurality of expected single-frequency signals on a line includes the steps of measuring the total signal energy on the line; measuring the signal energy present in each one of a plurality of selected separate frequency bands and identifying the two frequency bands having the highest signal energies; determining whether the highest signal energy exceeds a first selected threshold value; determining whether the highest signal energy exceeds the second highest signal energy by greater than a second selected threshold value; determining the amount of out-of-band signal energy; and determining whether the highest signal energy exceeds the out-of-band signal energy by greater than a third selected threshold value.

Abstract: A password controlled switching system and method of operation for enrolling and storing passwords identifying lines and trunks of the switching system denied access thereto by other lines and trunks and which is operable upon a match of a calling party command with an enrolled and stored password for selectively interconnecting the calling party via a line with ones of the restricted lines and trunks.

Abstract: A signalling receiver has its signal input (E) connected to a central-office trunk (a, b) in a trunk junctor and includes a variable bandpass filter (BP) connected to a clock line (TL). The signal input (E) is connected via an attenuator (DG) to a variable high-pass filter (HP) which is connected to the clock line (TL) and, via a signal evaluation and conversion unit (SE), to the bandpass filter (BP). A bandwidth switch (BU) is connected to the clock line (TL), the variable bandpass filter (BP), and the attenuator (DG). The cutoff frequency of the high-pass filter (HP) and the midband frequency of the bandpass filter (BP) are adjusted with a clock signal having a frequency related to the signal frequency to be received, the cutoff frequency being lower than the midband frequency.

Abstract: In a telephone switching system, a multifrequency code receiver unit is replaced by a voice-controlled dial signal receiver unit connected to the switching network via an adapter unit. The voice-controlled dial signal receiver unit contains a voice recognition unit, a voice output unit, and a control unit. A multifrequency code receiver is connected in parallel with the voice-controlled dial signal receiver unit and coupled to the adapter unit. The subscriber can enter dial information and service-feature-control information through the microphone of the handset of a telephone station and/or through a numeric keypad of the station. Instead of being informed of the respective line condition by tone signals, the subscriber receives this information in the form of speech from the voice output unit.

Abstract: A telephone switching network including a remote line switch that couples digital voice signals from a plurality of subscriber lines onto a lesser number of communications links connected to a central office. The remote line switch also includes an intra-nodal switch that switches telephone calls between subscriber lines connected thereto, so that the digital voice signals for the calls need not be transmitted to the central office for switching. The line switch, on receiving a request from the central office for a termination connection to a called line, determines whether both the calling and called lines are connected to it. If they are, and if the line's classes of service as supplied by the central office permit, the line switch establishes a path through its intra-nodal switch to switch the call.