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Class 708/311 - Frequency detection


Subclass of Class 708 - Electrical computers: arithmetic processing and calculating
Definition: Subject matter in which a subset of frequencies from a known
No. of patents: 53
Last issue date: 07/01/2008


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NumberTitleIssue Date
7394844Code division multiple access employing orthogonal filter banks
Wavelet filters computed from a wavelet transform are used for encoding, transmitting, receiving, and decoding spread spectrum signals on multiple parallel frequency channels. The transmitter encodes the data stream via a mapping to a basis set of wavelets which are...
07/01/2008
7239259Digitizer with enhanced accuracy
Systems and techniques for converting an analog input signal to a digital code are described. A system includes a differential stage to produce a sign bit indicative of a sign of the analog input signal and to generate a first analog signal that is approximately equ...
07/03/2007
7165130Method and system for an adaptive multimode media queue
Embodiments of the invention may provide a method for implementing an adaptive multimode media queue. A mode of operation may be determined for a received media stream based on a sampling rate of the media stream. The mode of operation may be a wideband mode and/or ...
01/16/2007
7003451Apparatus and method applying adaptive spectral whitening in a high-frequency reconstruction coding system
The present invention proposes a new method and a new apparatus for enhancement of audio source coding systems utilizing high frequency reconstruction (HFR). It utilizes adaptive filtering to reduce artifacts due to different tonal characteristics in different frequ...
02/21/2006
6948043Management of a memory subsystem
A method of optimizing performance of a memory subsystem in a computer system. This method including the step of informing the computer system of what type of memory module loading is present in the memory subsystem. The method also includes operating the memory sub...
09/20/2005
6943711Frequency-digital signal conversion circuit
There is provided a frequency-digital signal conversion circuit for automatically converting a clock frequency into a digital signal. The frequency-digital signal conversion circuit includes: a frequency detecting unit for detecting a frequency of an input clock sig...
09/13/2005
6928495Method and system for an adaptive multimode media queue
Embodiments of the invention may provide a method for implementing an adaptive multimode media queue. A mode of operation may be determined for a received media stream based on a sampling rate of the media stream. The mode of operation may be a wideband mode and/or ...
08/09/2005
6898214Technique for monitoring SONET signal
A technique for performance-monitoring of a standard SONET signal involves first converting the optical signal to an electrical signal, removing in the framing signal time slot the framing signal for leaving only the framing signal noise in such time slot, and separ...
05/24/2005
6856926Frequency margin testing of bladed servers
A frequency margin testing blade is adapted for use in a bladed server. The testing blade is further adapted to provide one or more output clock signals for use as clock inputs to one or more server blades internal to the bladed server in which the testing blade is ...
02/15/2005
6847598Servo with digital filter to control gain in a frequency band where open loop characteristic is higher than the phase cross-over frequency and lower than resonance frequency
The present invention implements a servo system which can support changes of the higher resonance frequencies of the actuator with a simple configuration at low cost. The servo system comprises a head 3 which at least reads a disk 1, a carriage 5
01/25/2005
6819731Frequency searching method and apparatus
The invention provides a method for searching the frequency range of a digital data receiving device, said method including the steps in one embodiment of firstly identifying and disregarding analogue carrier frequencies in the range, then proceeding to estimate the...
11/16/2004
6668057Apparatus for receiving tone signal, apparatus for transmitting tone signal, and apparatus for transmitting or receiving tone signal
An arithmetic processing section is designed to repeatedly execute product-sum arithmetic processing a number of times equal to the number of samples corresponding to each of the frequencies, in which a value obtained by subtracting a product-sum arithmet...
12/23/2003
6370555Method and system for improved detection of analog signals
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 recei...
04/09/2002
6026489Signal processor capable of executing microprograms with different step sizes
A signal processor stores at least one microprogram having m steps in total smaller in number than n steps which are to be executed within one sampling repetition period. A count corresponding to each of the n steps are generated. M steps of the at least ...
02/15/2000
5910905System and method for detection of dispersed broadband signals
A system and method for detecting the presence of dispersed broadband signals in real time. The present invention utilizes a bank of matched filters for detecting the received dispersed broadband signals. Each matched filter uses a respective robust time ...
06/08/1999
5796637Apparatus and method for filtering event signals
A system for filtering multiple event signals from multiple event-generating sources. A selection circuit receives the multiple event signals and selects one of the event signals. A filter circuit is coupled to the selection circuit and receives the selec...
08/18/1998
5699421Telephone answering device with low cost dual tone multi-frequency detector
A telephone answering device (TAD) includes a remote access mode which is operative responsive to dual tone multi-frequency (DTMF) signals. At least three bandpass filters each receive an input signal from a telephone line interface provided in the TAD. A...
12/16/1997
5583952Method and apparatus for representing an image by iteratively synthesizing high and low frequency components
An apparatus for decompressing an image that has been compressed by an image compression system in which the image is first repetitively filtered in one direction to produce a series of sub-images which are then repetitively filtered in a second direction...
12/10/1996
5477465Multi-frequency receiver with arbitrary center frequencies
A multi-frequency receiver for detecting the presence of one or more of a plurality of m frequency tones in an incoming signal. A digital signal processor executes a fast algorithm for accurately calculating the spectral energies in a plurality of m frequ...
12/19/1995
5272446Digitally implemented fast frequency estimator/demodulator for low bit rate maritime and mobile data communications without the use of an acquisition preamble
A low-bit-rate, low-cost, all-digital preambleless demodulator for maritime and mobile data communications operates under severe high noise conditions, fast Doppler frequency shifts, large frequency offsets, and multipath fading. Sophisticated algorithms,...
12/21/1993
5165051Modified fast frequency acquisition via adaptive least squares algorithm
This is a method and associated apparatus for accurately and quickly estimating the amplitude, frequency and phase of a signal of interest. The method comprises the steps of, inputting the signal of interest; generating a reference signal with adjustable ...
11/17/1992
5068911Method and apparatus for representing an image
An improved image compression system is disclosed in which the image is first repetitively filtered in one direction to produce a series of sub-images. These sub-images are then repetitively filtered in a second image to produce an image representation ha...
11/26/1991
4954961Method of digitally evaluating the frequency and the phase of signals, and a device for implementing such a method
A method of digitally evaluating the frequency and the phase of signals in the form of digitized samples, the method being wherein it comprises in succession: a stage during which numbers corresponding to the samples of the signal to be analyzed are proce...
09/04/1990
4614909Apparatus for identifying digital multi-frequency signals
An apparatus for identifying multi-frequency signals, the received signals being processed in selective receivers after having passed through a digital bandpass filter. The input signal to the receivers is multiplied at sampling times by a coefficient fro...
09/30/1986
4573135Digital lowpass filter having controllable gain
A digital lowpass filter having controllable gain produces a filtered digital signal by adding to the digital input signal a feedback signal produced from the filtered digital signal. The feedback signal is produced by a delay element and by a gain elemen...
02/25/1986
4570235Digital receiver of multifrequency signals with frequency recognition device
The present invention relates to a digital frequency recognition device for a receiver of multifrequency PCM signals, and consists essentially in forming characteristic values V(fi) for each frequency fi, in forming characteristic va...
02/11/1986
4484035Dual tone multi frequency digital detector
Dual tone multi frequency signals, such as those used in Touch-Tone.RTM. telephones, are digitally detected. In an eight tone frequency regime of four low frequencies (697 hz, 770 hz, 852 hz and 941 hz) and four high frequencies (1209 hz, 1336 hz, 1477 hz...
11/20/1984
4479188Digital detector for a multi-frequency code in an analog signal
This disclosure concerns a system for digitally detecting one or more of a plurality of fixed frequencies in an analog signal according to a correlation method, the fixed frequencies occurring in a first group and in a second group wherein a third harmoni...
10/23/1984
4455617Multiple simultaneous tone decoder
The invention is a decoder for decoding serially received signals. The decoder includes circuitry for calculating the period of each signal in a group of the serially received signals. The decoder averages the periods of the group and calculates the group...
06/19/1984
4442513Sonar transceiver system and method
A sonar transceiver system and method includes an oscillator and programmable divider which are arranged to cause a transmitting transducer to transmit a plurality of four consecutive closely spaced tones in the manner of a pseudo-chirp. The receiver incl...
04/10/1984
4399536Convolution filter arrangement for digital multifrequency receiver
A digital multifrequency (MF) receiver for use in telephone switching systems is disclosed. Input MF signals in a PCM (pulse code modulation) format are detected by simultaneously computing the convolution of the digital input signal with discrete portion...
08/16/1983
4363100Detection of tones in sampled signals
A tone detector in the form of a digital correlator is disclosed in which PCM signal samples are delayed in a RAM for the correlation period. Using PROMs, the products of the current and delayed samples with samples of a sine signal at the frequency to be...
12/07/1982
4361875Multiple tone detector and locator
A system (1000) for estimating the frequency of a tone input utilizes sample rate reduction in successive stages and processing by digital cyclotomic filters at each stage. The tone input (2001) is first transformed in network (1100) to yield two quadratu...
11/30/1982
4355405Digital signalling system
A digital MFC receiver using single band and multiband filters. The single band filters are tuned to respective ones of the signal frequencies. The multiband filters are used as guard filters producing interleaved guard bands between the signalling freque...
10/19/1982
4354248Programmable multifrequency tone receiver
A multifrequency tone receiver is disclosed for detecting simultaneous tone signals in a sampled digital signal. The tone receiver includes a microprogrammed sequence controller, a time-multiplexed digital filter and a signal processing microcomputer. For...
10/12/1982
4333150Signal receiving apparatus and method
A signal receiving apparatus and method are provided to decode an input signal to determine the presence of at least one desired frequency component in that input signal. A number of signal samples are taken in relation to the known frequency of that sign...
06/01/1982
4328398Digital multi-frequency receiver
A digital multi-frequency receiver for the use in an electronic telephone exchange system for detecting MF signals (700,900, 1100, 1300, 1500 and 1700 Hz) in the CCITT No. 5 system. The digital multi-frequency receiver comprises a recursive digital filter...
05/04/1982
4319325Digital processor for processing analog signals
An integrated circuit processor real time processing of analog signals is described. The programmable processor duplicates filters, waveform generators and non-linear functions, such as rectification, with a high degree of stability and at a relatively lo...
03/09/1982
4286326Digital devices for spectrum analysis
This invention relates to digital devices for spectral analysis. Signal x(t) of spectrum X(f), sampled at frequency 1/T and encoded, is processed by a temporal digital filter having a width NT followed by one or more perfect digital resonators in parallel, eac...
08/25/1981
4245325Digital multifrequency signalling receiver
Disclosed is a digital multifrequency signaling receiving system in which a first operation device executes an operation to multiply multifrequency signals composed of N samples as input signals by a window function including coefficients required for fas...
01/13/1981
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