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7602902 |
Method and apparatus for decoding DTMF tones
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...
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7529363 |
Tone detector and method therefor
A tone detector able to detect multicomponent tones for various tone formats is disclosed. An input signal is received and frequency and amplitude components, if any, of each sample of the incoming...
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7388954 |
Method and apparatus for tone indication
A communication system having an echo canceller is disclosed. One embodiment of the echo canceller includes an adaptive filter used to provide an estimate of reflected echo which is removed from...
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7277537 |
Tone, modulated tone, and saturated tone detection in a voice activity detection device
In a voice activity detection (VAD) device a method for defining tone signals comprises defining a threshold for zero amplitude change, calculating a zero crossing rate of a signal, extracting a...
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7272233 |
Acoustic shock prevention
Acoustic shock is reduced by attenuating an input signal based on tones detected through frequency domain analysis. The spectrum of the input signal is obtained. A relative energy signal includes a...
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7272136 |
Dual tone multi frequency signal detection
A signalling tone detector for use in a communications network for the detection of dual frequency multi-tone (DTMF) pairs of signal tones in a time division multiplex (TDM) signal. The detector...
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7245637 |
Methods and apparatus for suppressing signaling tones in telephony signal
In some embodiments, a method includes detecting a tone in each data frame of a sequence of telephony signal data frames. A first data frame of the sequence of telephony signal data frames may be...
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7236585 |
Apparatus and method for noise immunity during signal detection
A noise calculation mechanism is incorporated into a cadence tone detector which upon a miss in either a energy or silence interval allows for retention of those periods corresponding to noise and...
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7227943 |
Tone detector
The present invention provides a tone detector that is capable of performing accurate tone signal detection in a short period of time. Specifically, the tone detector according to the present...
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7187656 |
Method and system for processing tones to reduce false detection of fax and modem communications
A tone processing method and communications system which reduce the probability of falsely detecting modem and facsimile communications that occur on a communications link. The link connects a...
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7184542 |
DTMF tone detection
The present invention relates to the field of tone detection and, more particularly, to the detection of dual tone multi-frequency (DTMF) tones in software based telecommunications systems. As...
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7158543 |
V.8bis suppression method and apparatus for modem relay
The invented method involves one or more gateways sniffing the voice channel during the voice mode. If it is determined that V.8bis signals are being initiated, then the gateway breaks these...
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7139380 |
System and method for performing signaling-plan-specific call progress analysis
Call progress analysis is performed in a telephone system employing different in-band signaling plans are used. From address information for a call destination in a call initiation message, it is...
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7133521 |
Method and apparatus for DTMF detection and voice mixing in the CELP parameter domain
A method and apparatus for DTMF detection and voice mixing in the code-excited linear prediction (CELP) parameter space, without fully decoding and reconstructing the speech signal. The apparatus...
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7095845 |
Dual hysteresis signal detection circuit
A dual hysteresis signal detection circuit is proposed for detecting a duration of a signal with two hysteresis comparators. There is a first band pass filter for inputting the signal and...
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7088817 |
Method and apparatus for performing high-density DTMF, MF-R1, MF-R2 detection
Detectors determine the presence of valid sinusoids for DTMF, MF-R1 and MF-R2 protocols for encoding dialed digits. The detectors split electrical signals into subbands. Energies within the...
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7085371 |
Push-button signal receiving device and a gain control method
A push-button signal receiving device and a gain control method whereby error in validity determination of a received signal that accompanies the insertion of an AGC circuit can be prevented. An...
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7085370 |
Ringback detection circuit
A ringback detector determines whether ringback by comparing measurements of a characteristic of the received signal, such as the energy of the received signal, to a threshold. The threshold is set...
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7068781 |
Alarm of a telecommunications terminal connected to a LAN
Before any supply of remote power to a telecommunications terminal connected to a local area network, the Ethernet equipment must recognize the power class of the terminal by measuring a specific...
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7068734 |
Passive redundant digital data receiver with schmitt-trigger
A passive coupling structure constructed using printed circuit board traces is used to separate the low and high frequency components of an incoming digital signal. The low and high frequency...
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7054435 |
Apparatus and method for determining a minimal time bound for performing tone detection
Performing tone detection for an amount of time that is calculated from the tones that the detector is designed to detect.
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7050570 |
DTMF signal transmission method and communication apparatus
A communication apparatus connected to a PBX and an ATM network is provided with a DTMF signal detecting portion for detecting whether or not a DTMF signal is contained in a voice signal from the...
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7043012 |
Method and apparatus for ring again feature for a telephone system
A method and apparatus for an automatic ring again feature on a telephone set for a user that answers a telephone call not intended for that user is disclosed. If a user has answered an incoming...
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7035394 |
Tone detector judging a detection of a predetermined tone signal by comparing a characteristic quantity of the tone signal with characteristic quantities of other signals
A tone transmission part transmits a tone signal. A tone signal detection part detects data representing an echo signal of the tone signal transmitted by the tone transmission part, and detects...
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7023981 |
Method and apparatus for signal detection
A signal detector for detecting a signal having a first nominal frequency, F 1 and a second nominal frequency F 2 , the signal intermixed with an interfering signal to form a composite signal, the...
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7020274 |
Universal apparatus and method for interfacing signals with telephony networks
A communication apparatus is used to interface signals with any one of a plurality of telephony networks having different impedances. The apparatus includes memory, a processor, a digital-to-analog...
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7020272 |
High density signal classifier for media gateways
A signal classifier decomposes a subject signal into subbands. The signal classifier then analyzes the subbands for a presence of energy and uses detection logic to classify the energy as being...
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7010117 |
Multi-frequency tone detector
A multi-frequency tone detector with analysis window (i.e. filter size) chosen such that spectral nulls are located at adjacent frequencies of interest. The decision logic block of the tone...
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7003093 |
Tone detection for integrated telecommunications processing
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)...
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6950511 |
Detection of both voice and tones using Goertzel filters
A plurality of Goertzel filters whose operating frequencies are distributed across the voice baseband are used to detect voice and control tones in a signal. Filters operating at frequencies of...
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6940966 |
Method and apparatus for detection of a telephone CPE alerting signal
A method and apparatus for detecting a signaling tone within a communications channel, such as a telephone line, is presented. The energy level of the communications channel signal is measured at...
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6937717 |
Low power signal detection
The present invention provides a low power method and apparatus for detecting a signaling tone. The apparatus comprises a resonator which can be configured to resonate at a specified frequency, a...
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6925170 |
Wire-bound telecommunication device and a circuit for use in such a device
In known telephone subscriber end stations a caller_ID IC detects a tone alerting signal TAS alerting that successive caller_ID information can be received for displaying on a display of the phone....
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6914979 |
Tone detection
A DFT is used to compute the magnitude and phase of the frequencies desired to be detected in a frame of sampled data by performing 2 dot products for each such frequency. The two dot products are...
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6873701 |
System and method for DTMF detection using likelihood ratios
A system and method for determining DTMF coefficients stores a plurality of reference templates, at least some of said reference templates representative of likelihood ratios. A plurality of LPC...
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6868156 |
Non-voice signal repeater for speech coders
A method of repeating a non-voice signal such as a dual tone, multiple frequency (DTMF) signal, by inserting a delay sequence of data values into an output data sequence of data values, a portion...
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6850616 |
Frequency error detection methods and systems using the same
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...
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6842517 |
Meter pulse filtering circuit for analog modems
A filtering circuit is described for filtering out meter pulses of analog telephone communication, for example in analog modems. The circuit is mainly composed of resistors and capacitors and is...
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6813529 |
Method and apparatus for signal frequency decoding without an analog bandpass filter
An apparatus and method are provided for decoding single-frequency or multi-frequency signals, such as DTMF signals, without the use of analog bandpass filters. The method of the present invention...
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6813350 |
Method and apparatus for detecting dual tone alerting signal in telephone systems
An apparatus for detecting a dual tone alert signal in a telephone system capable of at least off hook mode operation includes a processing channel for each tone. Each channel consists of a...
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6801622 |
Devices, software and methods for passing DTMF signals under voice compression
Devices, software and methods are provided for encoding DTMF signals for telephone connections between digital voice communication systems that use compression, such as wireless connections or...
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6798880 |
System and method for suppressing in-band stimuli and telecommunications infrastructure incorporating the same
For use with analog telecommunications equipment that responds to in-band stimuli, a system for, and method of suppressing an in-band stimulus and a telecommunications infrastructure employing the...
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6782095 |
Method and apparatus for performing spectral processing in tone detection
A general purpose network tone detection method and apparatus that allows the precise and accurate recognition of North American tones (MF, DTMF (Dual-Tone Multifrequency), and CPT (Call Progress...
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6771767 |
Signal detector with coefficient swapping transform unit
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,...
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6763106 |
Signal detector with duration-based frame width
A signal detector for detecting at least a first signal having a first frequency and a first minimum duration is provided. The signal detector includes a matched transform unit and an energy level...
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6754324 |
Systems and methods for no-answer redial and connect
A calling party dials a called party, a no-answer status is received, and the called number is automatically redialed at intervals until receiving an answer status or reaching a maximum limit....
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6731747 |
Signal detector with echo cancellation
A system is disclosed for accurately detecting an alert signal. Improving detector accuracy decreases missed detects and false detects. In one example embodiment the detector monitors received...
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6728369 |
Method and device for distinguishing among a plurality of devices and data elements with a sequence of signals
A method and device for decoding a sequence of signals in which information is derived, in part, from a duration of (a) one of the signals and/or (b) an inter-signal pause between two of the...
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6711205 |
Tone detector for use in a modem
A tone detector for a modem detects the presence of a tone, such as that sent during a retraining request, using a complex adaptive FIR filter of the form 1−z −1 . The filter will detect the...
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6694011 |
Method and system for reliably detecting voiceband signaling tones
Reliably detecting voiceband signaling tones at a subscriber or network device in the presence of near-end and far-end speech occurs by eliminating, rather than balancing, near-end talk-off and by...
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