General Electric Company

Overtone Labs, Inc.

Analog Devices,inc.

Other

David Byrd Ribner

David Henry Hoe

David H Robertson

Michael A Wu

Jerome Johnson Tiemann

William E Engeler

Richard D Baertsch

Ravinder David Koilpillai

Sunder S Kidambi

Mark A Russell

Juha Mikko Hakkarainen

A resonance tuner receives and digitizes an analog signal in response to a resonance of a structure thereby creating a plurality of time samples. A series of the time samples are buffered upon burst detection. A power spectrum is estimated by computing a Time-To-Frequency-Transform of the series of time samples and a magnitude of each of the resulting frequency samples is squared. At least one subset associated with at least one spectral peak is selected from the frequency samples. Each spectral peak has at least one sample with a sufficient magnitude and being spectrally adjacent to any other sample in another spectral peak by less than a threshold. A fundamental spectral peak is determined in a fundamental subset including a spectral peak with a sample at the lowest frequency greater than zero. The fundamental spectral peak has the sample with the largest magnitude within the fundamental subset.

Drum and drum-set tuner

Provided are a percussion instrument tuning system and method. A position sensor determines at least one first position of a tuning mechanism of a timpano. A control unit generates a calibration result by measuring a first pitch of the timpano corresponding to the at least one first position of the tuning mechanism and estimates a second pitch of the timpano corresponding to at least one second position of the tuning mechanism from the calibration result.

Timpani tuning and pitch control system

Provided are systems and methods for resonance tuning. A signal is received in response to a resonance of a structure. A frequency or musical note related to an overtone is determined from the signal. The frequency or musical note related to the overtone is selected as a filter mode reference frequency or musical note. A display of frequencies or musical notes from a subsequent signal that deviate from the filter mode reference frequency or musical note by a predetermined threshold is suppressed.

A processor of a tuning apparatus receives a desired fundamental frequency or note and determines a frequency or note of at least one drumhead of a drum in response to the received desired fundamental frequency or note. An output at the processor outputs a value corresponding to the determined frequency or note of the drumhead.

Drum tuning processor

Drum-set tuner

A direct-digital synthesizer for generating a waveform includes a digital accumulator fed by a phase increment word and a series of clock pulses for successively adding the phase increment word to produce a series of N bit phase words. A table or trigonometric engine produces sine and cosine digital signals related to the M most significant bits of the phase word produced by the accumulator. A feedback loop is fed by truncation error words comprising at least a portion of N-M least significant bits of the N bit phase words producing truncation error compensation words. The feedback loop includes a digital filter. The feedback loop includes a digital filter. The feedback loop including the digital filter provides a low pass truncation error response to the truncation error having at least one zero in the transfer function thereof at DC. The truncation error response has a transfer function comprising the term (1&minus;az ) where: z is the discrete time frequency variable and a is a unity or non-unity weighting n factor. One such filter includes an adder fed by the truncation error words and a storage device fed by the clock pulses and by the truncation error words for producing at an output thereof the truncation error words delayed by each one of the clock pulses fed thereto. The adder is fed by the output of the storage device to produce an algebraic sum of the truncation error words fed to the adder and the delayed truncation.

Direct-digital synthesizers

An asymmetrical modem system wherein a modem at a first location transmits information to a modem at a second location on a downstream signal and the modem at the second location transmits information to the modem at the first location on an upstream signal. The system includes a first location transmitter section, having an N-point inverse frequency transform, for converting information into the downstream signal having up to (N/2)-1 carriers. A second location transmitter section having, an [(NL)/(2K)-point inverse frequency transform, converts information into the upstream analog signal having up to [(NL)/(2K)]-1 carriers, where K is the ratio of downstream signal bandwidth to upstream signal bandwidth and L is greater one. A receiver section at the first location, having an [NM/K]-point frequency transform, separates the upstream signal into up to [(NM)/(2K)]-1 upstream carriers, where M is greater than one. A receiver section at the second location, having an N-point frequency transform, separates the downstream analog signal into up to (N/2)-1 downstream carriers.

Asymmetric digital subscriber loop transceivers

A discrete multi-tone, asymmetrical transceiver and method wherein a modem at a central office transmits information to a modem at a remote terminal on a down-stream signal and the modem at the remote terminal transmits information to the modem at the central office on an up-stream signal. The up-stream signal comprising data carried by a lower portion of a predetermined band of frequencies and the down-stream signal comprising data carried by an upper portion of the predetermined band of frequencies. The system includes an interpolator, at the remote terminal, for adding interpolated data into a stream of data distributed by the remote terminal modem among the lower portion of the predetermined band of frequencies for transmission in the up-stream signal. An ADC is provided at the modem of the central office, for converting the down-stream signal into digital samples at a sampling rate greater than the frequency of the highest frequency in the down-stream signal. A decimator is fed samples from the ADC at the ADC sampling rate and produces output samples at a lower sampling rate. A demodulator is fed the samples produced by the decimator at the lower sampling rate and converts such samples into the lower portion of the predetermined band of frequencies. The interpolator increases the rate of samples produced on the up-stream signal and thereby increases the frequency of images in such up-stream signal for more effective removal by the band pass filter of the remote terminal. Images in the up-stream signal which may couple into the receiver at the central office are increased in frequency and then are effective filtering by the decimator.

Asymmetric digital subscriber loop transceiver and method

A method and apparatus for operating an asymmetric digital subscriber loop modem system. A modem at a central office transmits information to a modem at a remote terminal on a down-stream signal having a predetermined bandwidth and the modem at the remote terminal transmits information to the modem at the central office on an up-stream signal having a bandwidth lower than the predetermined bandwidth of the down-stream signal. Digital samples of the up-stream signal in the central office modem are produced. Digital samples representative of an estimated echo signal in the central office modem are also produced. The digital samples of the up-stream signal and the digital samples representative of an estimated echo signal are both fed to a subtractor at the same rate. In a preferred embodiment, the up-stream signal is oversampled (i.e., is sampled at a rate greater than the Nyquist sampling rate) in producing the digital samples thereof. Samples of the down-stream signal are fed to an echo cancellation filter. The filter output is decimated to a predetermined rate. The samples of the oversampled up-stream signal are decimated producing samples at the predetermined rate. Both the decimated samples of the oversampled up-stream signal and the decimated samples of the filter are fed to the subtractor at the predetermined rate.

Asymmetric digital subscriber loop modem and method

Delta sigma modulators for accepting input signals having amplitudes up to -1 dB of full-scale and a center frequency (F.sub.S) in the range �F.sub.S /90, 44F 90!, and which are not prone to internal overflow, require few circuit parameters, and yield a signal transfer function with the inherent property that the modulator magnitude response is close to unity gain in the frequency region of interest include, in one embodiment, a pair of cascaded integrators, a unit delay element coupled to the output of the second integrator, an analog-to-digital (A/D) converter, and a one-bit digital-to-analog (D/A) converter controlled by output signals from the A/D converter. A first differential summing junction coupled to the output of the D/A converter is responsive to delta sigma modulator input signals. A second differential summing junction, coupled to the output of the first differential summing junction, is also coupled to receive a feedback signal from the second integrator. A third differential summing junction, coupled to the output of the unit delay element, also receives feed-forward signals from the second integrator.

Feed-forward bandpass delta-sigma converter with tunable center frequency

A data transmission system including a telephone service subscriber loop utilized for transmission of data including telephone service signals; a splitter operable for splitting the subscriber loop into a first transmission path including a low pass filter which accommodates a continuation of telephone service signal transmissions along the subscriber loop and a second transmission path, said second transmission path including a capacitive element for attenuating the telephone service signals; and a digital subscriber loop transceiver coupled to the second transmission path for implementing high rate digital data transmission over the subscriber loop, the transceiver including a frontend processing circuit having a transmit path and a receive path, at least said receive path comprising a high pass filter for further attenuating said telephone service signals. The capacitive element in the second transmission path and the high pass filter in the receive path of the transceiver frontend operate in conjunction to maintain transhybrid loss.

Pots splitter assembly with improved transhybrid loss for digital

A delta sigma modulator that has a low power dissipation without sacrificing modulator resolution includes, in one embodiment, a current mode digital to analog converter (DAC) in shunt with a conventional op amp in the first stage of the delta sigma modulator. By adding the current mode DAC in shunt with the first (or only) stage op amp of the delta sigma modulator, the slewing current needed during transients is provided by the combination of the op amp and DAC output signals. Since the DAC provides the slewing current required for the output signal change, the op amp need not apply the slewing current and therefore need only operate at low quiescent power.

Low power delta sigma converter

A delta sigma modulator which enables each cascaded integrator to settle independently within a full clock period and uses binomial coefficients in the feedback paths to obtain the required sinusoidal shaping of quantizer error, achieves an increase in both the sampling rate and the order to improve resolution. Using a multi-bit quantizer also improves modulator resolution. In one embodiment, the modulator includes a plurality of cascaded unit-delay integrators and utilizes binomial coefficient scaling in the feedback loop. A multi-bit analog-to-digital converter is coupled to receive the output signal of the cascaded unit-delay integrators. The feedback loop includes a multi-bit digital-to-analog converter coupled to the output of the multi-bit analog-to-digital converter. The output of the digital-to-analog converter is coupled to the inputs of at least the first and second differential summing junctions.

Growing community of inventors

Andover, MA, United States of America

David Byrd Ribner