Advanced Micro Devices Corporation

Legerity, Inc.

John G Bartkowiak

Safdar M Asghar

Mark A Ireton

Saf M Asghar

Michael A Nix

Joseph W Peterson

Zheng-yi Xie

Jacqueline E Mullins

Alan F Hendrickson

Thang M Tran

Dale E Gulick

Munehiro Yoshikawa

Thomas W Lynch

Miki Z Moyal

Shin Saito

James E Bowles

Hiroshi Matsubara

Daren L Allee

Costas S Xydeas

Dimitris Hiotakakos

Eric A Suss

An apparatus for detecting at least one tone having a known frequency and duration in an input signal. The input signal is input over a period of time which is divided into frame portions including at least an initial frame portion and a last frame portion. An energy signal indicative of the energy of the input signal during each frame portion is generated. A signal filter receives the energy signal and generates a noise indicator for each frame portion based on whether noise is detected in the energy signal. A dynamic threshold determiner generates an energy threshold for each frame portion. The energy threshold for the initial frame portion is generated based on a minimum expected value of the energy signal for a subsequent frame portion. The energy thresholds for frame portions subsequent to the initial frame portion are generated based on values of the energy signals during previous frame portions and the noise indicator. A signal processor determines when the input signal includes the at least one tone based on the energy threshold, the noise indicator, and the energy signal.

Tone detector with noise detection and dynamic thresholding for robust performance

A transcoder-codec circuit arrangement that supports voice-switched hands-free radio operation. A first register is arranged to store a value indicative of a peak signal in a receive signal path, a first attenuator is coupled to the receive path, a second register is arranged to store a value indicative of a peak signal in a transmit signal path, a second attenuator is coupled to the transmit signal path, and a digital signal processor is coupled to the first and second registers and configured and arranged to update the value in the first register with a present peak receive signal level if the value in the first register is less than the present peak receive signal level. The digital signal processor is further arranged to update the value in the second register to a present peak transmit signal level if the value in the second register is less than the present peak transmit signal level. A microcontroller is coupled to the first and second registers and to the first and second attenuators and is configured to read values from the first and second register and adjust the first and second attenuators in response to the values.

Transcoder-codec circuit arrangement and method that supports voice-switched hands-free radio operation

A method and system for improved detection of analog signals, where the analog signals may be composed of one or more analog frequencies. In the method and system, an analog signal is received. A stream of data samples is created from the analog signal. Based on the stream of data samples, a confidence factor regarding the presence of the one or more analog signals is created. The confidence factor is created based upon a confidence factor calculated for each of the one or more analog frequency signals. The confidence factor calculated for each of the one or more analog frequency signals is calculated utilizing incremental energies associated with each of the one or more analog frequency signals.

Method and system for improved analog signal detection

A signal detector includes a transform unit and a cross-frame energy level unit. The transform unit is adapted to receive at least a first and a second frame of time domain input samples. The transform unit generates at least a first frequency energy value for the first frame and a second frequency energy value for the second frame based on the time domain input samples. The cross-frame energy level unit is adapted to compare the first frequency energy value to the second frequency energy value to determine the presence of a first tone in the time domain input samples. A method for detecting a signal includes receiving at least a first and a second frame of time domain input samples. At least a first frequency energy value for the first frame and a second frequency energy value for the second frame are generated based on the time domain input samples. The first frequency energy value is compared to the second frequency energy value to determine the presence of a first tone in the time domain input samples.

Cross-frame dual tone multifrequency detector

An apparatus for determining energy threshold detection values for detecting at least one tone having a known frequency and duration in an input signal. The input signal is input over a period of time that is divided into frame portions including at least an initial frame portion and a last frame portion. An energy value is determined for the at least one tone during each frame portion. A set of control flag signals are set for the at least two frame portions based on the energy values being below a threshold value in previous frame portions and the presence of noise in previous frame portions. An offset into a data table is determined based on the control word, the offset being used to retrieve a scaling coefficient and an address of an energy value for the at least two frame portions from the data table. A second set of control flag signals provide information on the number of comparisons to energy values from previous frames that are required to determine the energy threshold detection value for each frame portion.

Efficient dynamic energy thresholding in multiple-tone multiple frequency detectors

A method and system for improved detection of analog signals, where such signals are composed of one or more analog frequencies of defined duration. In the method and system, an analog signal is received. A stream of data samples is created from the received analog signal. Based on the stream of data samples, a duration is calculated for one or more analog frequencies contained within the received analog signal. The duration is calculated for the one or more frequencies by utilizing a calculated signal energy for each of the one or more analog frequencies. The calculated signal energies for each of the one or more analog frequencies are used to determine a number of frequency-specific data samples. The number of frequency-specific data samples are then utilized with a sampling rate to calculate the duration of the each of the one or more analog frequencies. The one or more calculated durations of each of the one or more analog frequencies are utilized to determine whether the analog signal, composed of the one or more analog frequencies of defined duration, is present.

Method and system for improved detection of analog signals

A communications device is presented including a DTMF detector for detecting a DTMF signal. When the DTMF signal is a Mode 2 Caller ID CAS, the first DTMF tone has a frequency of about 2130 Hz, and the second DTMF tone has a frequency of approximately 2750 Hz. An input signal includes signal energy within a first portion of the input signal frequency range which includes the first DTMF tone, signal energy within a second portion of the input signal frequency range which includes the second DTMF tone, and signal energy within a third portion of the input signal frequency range which excludes the first and second DTMF tones. The DTMF signal detector includes a first and second tone detection units, an extraneous signal detection unit, and detection logic. The first and second tone detection units receive the input signal and produce an output signal dependent upon the signal energy within the respective first and second portions of the input signal frequency range. The extraneous signal detection unit also receives the input signal and produces an output signal dependent upon the signal energy within the third portion of the input signal frequency range. The detection logic receives the output signals produced by the first and second tone detection units and the extraneous signal detection unit, and produces a DTMF detect signal dependent upon the output signals.

Communications device including an improved CPE alerting signal (CAS) detection system

The communications processor of the present invention comprises, in a single integrated circuit chip, the combination of a central processing unit (CPU) having an execution unit with an arithmetic logic unit and accumulators, a program counter, memory, a clock generator, a timer, a bus interface, chip select outputs, and an interrupt processor; a digital signal processor (DSP) having an instruction set to carry out a digital signal processing algorithm, an execution unit for carrying out multiply and accumulate operations and an external interface; an address bus connected between the CPU and the DSP; a data bus connected between the CPU and the DSP; and a static scheduler for statically scheduling execution of the signal processing algorithm between the digital signal processor and the CPU.

Communications processor for voice band telecommunications

A signal detector includes a transform unit and a signal alignment unit. The transform unit is adapted to receive a plurality of frames of time domain input samples and generate a plurality of energy values based on the frames of time domain input samples. Each energy value is associated with one of the plurality of frames. The signal alignment unit is adapted to identify at least a first partial energy frame and a second partial energy frame from the plurality of frames. The first partial energy frame is associated with a first frequency and has a first energy value. The second partial energy frame is associated with a second frequency and has a second energy value. The signal alignment unit determines a misalignment between the first and second partial energy frames based on the first and second energy values. A method for detecting a signal is provided. The method includes generating a plurality of energy values based on the frames of time domain input samples. Each energy value is associated with one of the plurality of frames. At least a first partial energy frame and a second partial energy frame are identified from the plurality of frames. The first partial energy frame is associated with a first frequency and has a first energy value. The second partial energy frame is associated with a second frequency and has a second energy value. A misalignment between the first and second partial energy frames is determined based on the first and second energy values.

Method and apparatus for detecting signal misalignment

The present invention comprises an improved vocoder system and method for estimating the pitch of a speech signal. The speech signal comprises a stream of digitized speech samples. The speech samples are partitioned into frames. For each frame of the speech signal, an optimal order-two inverse filter is determined. The optimal order-two inverse filter is determined by computing an order-two inverse filter at various locations within the speech frame. For each order-two inverse filter an energy value is calculated which represents the proportion of energy which would remain if the speech signal were filtered with the order-two inverse filter. The order-two inverse filter which minimizes the energy proportion is chosen to be the optimal order-two inverse filter. The optimal order-two inverse filter is then used to filter the samples of the speech frame. An autocorrelation is performed on the filtered signal for a range of tine-delay values. The peaks of the autocorrelation function are analyzed to determine the pitch period.

System and method for determining a first formant analysis filter and

A vocoder system and method for estimating the pitch of a speech signal. The speech signal comprises a stream of digitized speech samples. The speech samples are partitioned into frames. For each frame of the speech signal, the following processing steps are performed. First, an optimal order-two inverse filter is determined based on the samples of the speech frame. Second, a dominant formant frequency is calculated from the coefficients of the optimal order-two inverse filter. Third, an autocorrelation function is calculated on the samples of the speech frame. The autocorrelation is performed for a range of time-delay values over which the pitch period and its multiples might be expected to occur. Fourth, the peaks of the autocorrelation function are analyzed incorporating the knowledge of the dominant formant period (which is the inverse of the dominant formant frequency). Normally, the dominant formant is the first formant. Thus, the dominant formant period defines the expected time-delay for the first formant peak in the autocorrelation function. As such, any peak in the autocorrelation function occurring with a time-delay equal to the dominant formant period is treated with increased caution before being accepted as the pitch period.

First formant location determination and removal from speech correlation

Disclosed is a system for selectively enabling intermediate data processing of digital signals external to an integrated circuit (IC). The system comprises a transcoder, a codec connected to the transcoder, and a data processor located externally to the IC. In response to a strobe signal, a programmable switch diverts digital signals between the transcoder and the codec to a data path from the IC to the external processor. The digital signals are formatted within the IC for processing by the external processor. The externally processed digital signals are returned to the IC via a data path from the external processor. The digital signals are then reformatted within the IC for further processing by the IC.

Method and apparatus for external intermediate data processing

An improved vocoder system and method for estimating pitch in a speech waveform which pre-filters speech data with improved efficiency and reduced computational requirements. The vocoder system is preferably a low bit rate speech coder which analyzes a plurality of frames of speech data in parallel. Once the LPC filter coefficients and the pitch for a first frame have been calculated, the vocoder then looks ahead to the next frame to estimate the pitch, i.e., to estimate the pitch of the next frame. In the preferred embodiment of the invention, the vocoder filters speech data in a second frame using a plurality of the coefficients from a first frame as a multi pole analysis filter. These coefficients are used as a 'crude' two pole analysis filter. The vocoder preferably includes a first processor which performs coefficient calculations for the second frame, and a second processor which performs pre-filtering and pitch estimation, wherein the second processor operates substantially simultaneously with the first processor. Thus, the vocoder system uses LPC coefficients for a first frame as a 'crude' multi pole analysis filter for a subsequent frame of data, thereby performing pre-filtering on a frame without requiring previous coefficient calculations for that frame. This allows pre-filtered pitch estimation and LPC coefficient calculations to be performed in parallel. This provides a more efficient pitch estimation, thus enhancing vocoder performance.

System and method for improved pitch estimation which performs first

A microprocessor configured to detect a memory operation having a predefined data address is provided. The predefined data address indicates that subsequent instructions belong to an alternate instruction set. In one embodiment, a second memory operation having the predefined data address indicates that instructions subsequent to the second memory operation belong to the original instruction set. The memory operations effectively provide a boundary between the instructions from dissimilar instruction sets. Instructions are routed to an execution unit configured to execute the instruction set indicated by the most recently detected memory operation having the predefined address. Each instruction sequence within the program may be coded using the instruction set which most efficiently executes the function corresponding to the instruction sequence. The program may be executed more quickly than an equivalent program coded entirely in either instruction set. In one embodiment, the microprocessor executes the x86 instruction set and the ADSP 2171 instruction set.

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Austin, TX, United States of America

John G Bartkowiak