scispace - formally typeset
Search or ask a question

Showing papers on "Digital signal published in 2004"


Journal ArticleDOI
TL;DR: An improved algorithm with one-period prediction of current for a voltage-source inverter controller that was realized in an experimental system with DSP and field-programmable gate array circuits.
Abstract: A new predictive current controller for a voltage-source inverter is presented in this paper. Practical aspects of realizing the new controller in a system with a digital signal processor (DSP) are considered. Delays introduced by measurements are considered and an improved algorithm with one-period prediction of current is presented. The controller was realized in an experimental system with DSP and field-programmable gate array circuits. Results of the simulations and experiments are presented.

263 citations


Journal ArticleDOI
TL;DR: A new biochip consisting of an array of microelectrodes with fully-integrated analog and digital circuitry realized in an industrial CMOS process addresses signal degradation and array size issues, thereby facilitating simultaneous stimulation and recording of electrogenic cell activity.

177 citations


Patent
11 Feb 2004
TL;DR: In this paper, the authors propose an all-metallic transmission-line structure is maintained from the output interconnections in the driver to the input interconnection in the receiver.
Abstract: Apparatus for transmitting a digital signal within, for example, an integrated circuit includes a signal transmission line with a directional coupler at one or both ends. The directional coupler blocks the direct-current component of the digital signal while transmitting the alternating-current component, including enough higher harmonics to transmit a well-defined pulse waveform. A suitable directional coupler consists of two adjacent line pairs in materials with different dielectric constants. The apparatus may also include a driver of the inverter type, a receiver of the differential amplifier type, a terminating resistor, and a power-ground transmission line pair for supplying power to the driver. An all-metallic transmission-line structure is preferably maintained from the output interconnections in the driver to the input interconnections in the receiver.

169 citations


Patent
Jang Hyun Jeong1
08 Dec 2004
TL;DR: In this article, a solid-state image-sensing device that compensates for brightness at edges of a screen and a method of driving the device is provided, which consists of an active pixel sensor array including pixels disposed in a two-dimensional matrix, each pixel for outputting a photoelectrically converted image signal generated by a photodiode in response to one of a plurality of transmission control signals transmitted to a selected row of the APS array, and for generating and outputting an analog signal corresponding to a difference between the image signal and the reset signal into a
Abstract: A solid-state image-sensing device that compensates for brightness at edges of a screen and a method of driving the device are provided. The solid-state image-sensing device comprises: an active pixel sensor (APS) array including pixels disposed in a two-dimensional matrix, each pixel for outputting a photoelectrically converted image signal generated by a photodiode in response to one of a plurality of transmission control signals transmitted to a selected row of the APS array, and for generating and outputting a reset signal in response to a reset control signal; a row driver for selecting a row of the APS array by generating row selection signals and for generating the reset control signal; an integration time control driver for generating the transmission control signals for setting non-uniform integration times of the photodiodes in each pixel; and an analog-digital converter for converting an analog signal corresponding to a difference between the image signal and the reset signal into a digital signal.

162 citations


Patent
27 Oct 2004
TL;DR: In this paper, a transmission system for transmitting digital information via a power supply network is described, which consists of a generator for generating a simulated digital wave-form carrying the digital information to be transmitted, and a high-voltage injector to inject the generated simulated digital signal into the power supply.
Abstract: Disclosed is a transmission system for transmitting digital information via a power supply network. In one embodiment, there is a transmission device which comprises a generator for generating a simulated digital wave-form carrying the digital information to be transmitted, and a high-voltage injector to inject the generated simulated digital wave-form carrying the digital information into the power supply network. A receiving device is also disclosed, which comprises an analog detector for detecting predetermined harmonic frequencies of a signal frequency, and a logic device to output a logic signal corresponding to the output of the analog detector as said digital information.

151 citations


Proceedings ArticleDOI
13 Sep 2004
TL;DR: A discrete-time receiver architecture for a wireless application is presented and analog signal processing concepts are used to directly sample the RF input at Nyquist rate.
Abstract: A discrete-time receiver architecture for a wireless application is presented. Analog signal processing concepts are used to directly sample the RF input at Nyquist rate. Maximum receiver sensitivity is -83dBm and the chip consumes a total of 41mA from a 1.575V internally regulated supply. The receiver is implemented in a 0.13/spl mu/m digital CMOS process.

136 citations


Patent
23 Jan 2004
TL;DR: In this article, the authors provided a novel communication system having a forward link comprising: at least one base station which transmits multiple radio frequency (RF) signals; and a mobile station, the mobile station including: a receiver for receiving the RF signals; means for converting the RF signal to an intermediate frequency (IF) signal; means (704) for sampling the IF signal to generate a digital signal, the digital signal having a data component.
Abstract: According to a first broad aspect of the present invention, there is provided a novel communication system having a forward link comprising: at least one base station which transmits multiple radio frequency (RF) signals; and a mobile station, the mobile station including: a receiver for receiving the RF signals; means for converting the RF signal to an intermediate frequency (IF) signal; means (704) for sampling the IF signal to generate a digital signal, the digital signal having a data component; means (712) for canceling co-channel and or cross-channel interference in the digital signal by projecting the IF signal into a subspace orthogonal to a subspace of the interference component and multiplying this projection with the digital signal; and means (710) for acquisition and tracking of the digital signal.

133 citations


Journal ArticleDOI
TL;DR: The paper provides an explanation of MCTF methods and the resulting 3D wavelet representation, and shows results obtained in the context of encoding digital cinema (DC) materials.
Abstract: Scalability at the bitstream level is an important feature for encoded video that is to be transmitted and stored with a variety of target rates or to be replayed on devices with different capabilities and resolutions. This is attractive for digital cinema applications, where the same encoded source representation could seamlessly be used for purposes of archival and various distribution channels. Conventional high-performance video compression schemes are based on the method of motion-compensated prediction, using a recursive loop in the prediction process. Due to this recursion and the inherent drift in cases of deviation between encoder and decoder states, scalability is difficult to realize and typically effects a penalty in compression performance for prediction-based coders. The method of interframe wavelet coding overcomes this limitation by replacing the prediction along the time axis by a wavelet filter, which can nevertheless be operated in combination with motion compensation. Recent advances in motion-compensated temporal filtering (MCTF) have proven that combination with arbitrary motion compensation methods is possible. Compression performance is achieved that is comparable with state of the art single-layer coders targeting only for one rate. The paper provides an explanation of MCTF methods and the resulting 3D wavelet representation, and shows results obtained in the context of encoding digital cinema (DC) materials.

127 citations


Patent
28 Jan 2004
TL;DR: In this paper, a digital payload for processing a sub-band spectrum received on an uplink beam at a communications satellite includes a digital channelizer, a digital switch matrix and a digital combiner.
Abstract: A digital payload for processing a sub-band spectrum received on an uplink beam at a communications satellite includes a digital channelizer, a digital switch matrix and a digital combiner. The digital channelizer divides the sub-band spectrum into a plurality of frequency slices that can be routed by the digital switch matrix to any of a number of receiving ports. A digital combiner receives the frequency slices and re-assembles them to form one or more output sub-bands for transmission on an output beam of the communications satellite. The digital payload may also include an embeddable digital regeneration module configured to demodulate some or all of the sub-band spectrum to extract a digital bitstream therefrom. The digital bitstream may be processed to implement code-based multiplexing, switching, access control, and other features.

110 citations


Patent
23 Mar 2004
TL;DR: In this article, a transmission signal and a pilot signal are predistorted by a digital predistorter by use of a power-series model, and the output is converted by digital-analog converter 14 to an analog signal.
Abstract: A transmission signal and a pilot signal are predistorted by a digital predistorter 13 by use of a power-series model, and the predistorted output is converted by a digital-analog converter 14 to an analog signal. The analog signal is up converted by a frequency converter 15 to an RF-band signal, which is transmitted after being power-amplified by a Doherty amplifier 16. The pilot signal is extracted by a pilot signal extractor 17 from the output from the Doherty amplifier, and the extracted pilot signal is down converted by a frequency converter 18 to a baseband signal. The baseband pilot signal is converted by an analog-digital converter 19 to a digital pilot signal. A control part 21 detects an odd-order distortion component from the digital pilot signal, and based on the detected result, controls parameters of the digital predistorter.

107 citations


Proceedings ArticleDOI
18 Jun 2004
TL;DR: The method described is both aurally transparent and robust and can be applied to both analog and digital audio signals, the latter including uncompressed as well as compressed audio file formats such as MP3.
Abstract: Data hiding in media, including images, video, and audio, and in data files is currently of great interest both commercially, mainly for the protection of copyrighted digital media, and to the government and law enforcement in the context of information system security and covert communications. We present a technique for inserting and recovering "hidden" data in audio files. The phase of chosen components of the host audio signal is manipulated in a way that may be detected by a receiver with the proper "key". Without the key, the hidden data is undetectable, both aurally and via blind digital signal processing attacks. The method described is both aurally transparent and robust and can be applied to both analog and digital audio signals, the latter including uncompressed as well as compressed audio file formats such as MP3.

Patent
30 Dec 2004
TL;DR: In this article, the carrier signal independent data is encoded in a manner such that it is restricted or concentrated primarily in the non-deterministic signal components of the carrier signals and the signal components can include a discrete series of digital samples and/or a discreet series of carrier frequency sub-bands.
Abstract: Z-transform calculations may be used to encode (and/or decode) carrier signal independent data (e.g., digital watermarks) to a digital sample stream. Deterministic and non-deterministic components of a digital sample stream signal may be analyzed for the purposes of encoding carrier signal independent data to the digital sample stream. The carrier signal independent data may be encoded in a manner such that it is restricted or concentrated primarily in the non-deterministic signal components of the carrier signal. The signal components can include a discrete series of digital samples and/or a discreet series of carrier frequency sub-bands of the carrier signal. Z-transform calculations may be used to measure a desirability of particular locations and a sample stream in which to encode the carrier signal independent data.

Patent
30 Jan 2004
TL;DR: In this paper, a linear amplification with nonlinear components (LINC) power transmitter is presented, which includes a digital signal processing unit which controls the LINC power transmitter, a frequency modulation unit which modulates or converts the digital signal output from the digital signals processing unit into a radio-frequency (RF) signal, and a signal amplification unit which amplifies the RF signal output using a gain amplifier and a power amplification module.
Abstract: A linear amplification with nonlinear components (LINC) power transmitter is provided. The LINC power transmitter includes a digital signal processing unit which controls the LINC power transmitter; a frequency modulation unit which modulates or converts a digital signal output from the digital signal processing unit into a radio-frequency (RF) signal; a signal amplification unit which amplifies the RF signal output from the frequency modulation unit using a gain amplifier and a power amplification module; and a direct current/direct current (DC/DC) conversion unit which controls bias of the power amplification module. Here, the DC/DC conversion unit controls a base bias and/or a collect bias of the power amplification module, and the power amplification module operates in saturation.

Patent
Kil-Soo Park1
12 Jul 2004
TL;DR: In this article, the authors present a method of determining a display mode from a plurality of display modes for a display device that displays an image, each display mode relates to an inputted signal from a signal source that includes an analog signal and an H/V synchronization signal.
Abstract: The present invention relates to an apparatus and a method of determining a display mode from a plurality of display modes for a display device that displays an image, each display mode relates to an inputted signal from a signal source that includes an analog signal and an H/V synchronization signal, the method including determining at least one display mode corresponding to the inputted H/V synchronization signal; converting the inputted analog signal to a digital signal according to a sampling signal corresponding to each of the at least one determined display mode; and displaying the image using a display mode from the at least one determined display mode that most closely relates to the signal source.

Patent
TL;DR: In this article, the level of each frequency band signal is computed and compared to at least one plurality of threshold values to determine which signal processing schemes are to be applied to the signal.
Abstract: An improved hearing aid, and processes for adaptively processing signals therein to improve the perception of desired sounds by a user thereof. In one broad aspect, the present invention relates to a process in which one or more signal processing methods are applied to frequency band signals derived from an input digital signal. The level of each frequency band signal is computed and compared to at least one plurality of threshold values to determine which signal processing schemes are to be applied. In one embodiment of the invention, each plurality of threshold values to which levels of the frequency band signals are compared, is derived from a speech-shaped spectrum. Additional measures such as amplitude modulation or a signal index may also be employed and compared to corresponding threshold values in the determination.

Patent
28 Oct 2004
TL;DR: In this paper, a capacitive isolation barrier across which a digital signal is communicated is provided, where clock recovery circuitry is employed on one side of the barrier to extract timing information from the digital signal communicated across the barrier, and to filter the effects of phase noise introduced at the barrier.
Abstract: An isolation system is provided that is suitable for use in telephony, medical instrumentation, industrial process control and other applications. Preferred embodiments of the invention comprise a capacitive isolation barrier across which a digital signal is communicated. The system provides a means of communication across the isolation barrier that is highly immune to amplitude and phase noise interference. Clock recovery circuitry may be employed on one side of the isolation barrier to extract timing information from the digital signal communicated across the barrier, and to filter the effects of phase noise introduced at the barrier. Delta-sigma converters may be disposed on both sides of the isolation barrier to convert signals between analog and digital domains. An isolated power supply may also be provided on the isolated side of the barrier, whereby direct current is generated in response to the digital data received across the isolation barrier. A bidirectional isolation system is provided whereby bidirectional communication of digital signals is accomplished using a single pair of isolation capacitors. In preferred embodiments, the digital data communicated across the barrier consists of digital delta-sigma data signals multiplexed in time with other digital control, signaling and framing information. Finally, the isolation system may include a pulse transformer to accommodate ADSL circuitry, whereby power is transmitted through the pulse transformer.

Journal ArticleDOI
TL;DR: Two DASP approaches for spectrum estimation of continuous-time signals are presented, named the weighted sample (WS) and weighted probability (WP) density functions, respectively, which utilize random sampling to suppress aliasing and produce unbiased estimators of the signal spectrum.
Abstract: Nonuniform sampling can facilitate digital alias-free signal processing (DASP), i.e., digital signal processing that is not affected by aliasing. This paper presents two DASP approaches for spectrum estimation of continuous-time signals. The proposed algorithms, named the weighted sample (WS) and weighted probability (WP) density functions, respectively, utilize random sampling to suppress aliasing. Both methods produce unbiased estimators of the signal spectrum. To achieve this effect, the computational procedure for each method has been suitably matched with the probability density function characterising the pseudorandom generators of the sampling instants. Both proposed methods are analyzed, and the qualities of the estimators they produce have been compared with each other. Although none of the proposed spectrum estimators is universally better than the other one, it has been shown that in practical cases, the WP estimator produces generally smaller errors than those obtained from WS estimation. A practical limitation of the approaches caused by the sampling-instant jitter is also studied. It has been proven that in the presence of jitter, the theoretically infinite bandwidths of WS and WP signal analyses are limited. The maximum frequency up to which these analyses can be performed is inversely proportional to the size of the jitter.

Patent
03 Mar 2004
TL;DR: In this article, the authors present a system and method for converting digital data audio data audio audio data that has a predetermined input sample rate, into an analog data signal using a digital to analog converter (DAC).
Abstract: Provided is a system and method for converting digital data audio data audio data that has a predetermined input sample rate, into an analog data signal. A system includes a digital to analog converter (DAC) including a digital processing portion configured to receive as an input the digital audio data and timing information, the timing information being representative of a time base of the input sample rate. The digital processing portion is similarly configured to digitally process the digital audio data and the timing information to produce serialized output data. The DAC also includes an analog processing portion configured to convert serialized data to an analog format. The digital processing portion operates in accordance with at least one clock having a corresponding clock rate wherein the corresponding clock rate is unrelated to the input sample rate.

Patent
15 Jul 2004
TL;DR: In this paper, a new digital architecture for metallic pipe and cable locators, providing accurate estimation of the fundamental locate parameters, electromagnetic signal strength and signal direction, and utilizing a nested Digital Phase-Locked Loop (DPLL) structure is disclosed.
Abstract: A new digital architecture for metallic pipe and cable locators, providing accurate estimation of the fundamental locate parameters, electromagnetic signal strength and signal direction, and utilizing a nested Digital Phase-Locked Loop (DPLL) structure is disclosed. The obstacles to signal direction measurement in low SINR environments using the signal select method are overcome and a more precise phase comparison between the carrier and the FM modulation signals is obtained. The architecture further significantly reduces analog front-end hardware requirements, offers wider resistance to component tolerances, lower calibration and test time, and provides flexible frequency selectivity. Locators according to the present invention provide accurate estimation of the fundamental physical parameters of line location (electromagnetic signal strength and signal direction) in extremely noisy environments, using Digital Signal Processing (DSP) methods.

Patent
Sang-Il Lee1, Yun-Je Oh1, Jong-Hun Lee1, Jong-Hwa Lee1, Kwon Seo Won1, Yun-Kyung Oh1 
21 Apr 2004
TL;DR: In this article, an indoor local area network (LAN) system using an ultra wideband (UWB) communication system is provided, which includes at least one remote terminal including a UWB module for converting input digital data to be transmitted into an analog signal of an UWB and wirelessly transmitting the converted analog signal via an antenna of the remote terminal.
Abstract: An indoor local area network (LAN) system using an ultra wide-band (UWB) communication system is provided. The indoor LAN system includes at least one remote terminal including a UWB module for converting input digital data to be transmitted into an analog signal of an ultra wide-bandwidth and wirelessly transmitting the converted analog signal via an antenna of the remote terminal. The UWB module receives an analog signal of the ultra wide-bandwidth via the antenna and converts the received analog signal into a digital signal. The indoor LAN system further includes at least one access point for performing USB-based wireless communication with the remote terminal in a corresponding area. The access point is adapted to receive the analog signal of the ultra wide-bandwidth transmitted from the remote terminal and convert the received analog signal into an optical signal

Patent
18 Nov 2004
TL;DR: In this article, the authors propose an intelligent electronic device (IED) consisting of a base module having a power monitoring circuit operative to monitor a parameter of a portion of a power distribution system and generate an analog signal representative thereof.
Abstract: An intelligent electronic device (IED) includes a base module having a power monitoring circuit operative to monitor a parameter of a portion of a power distribution system and generate an analog signal representative thereof. The base module also includes a processor coupled with the power monitoring circuit, the processor having an analog to digital converter operative to convert the analog signal to a digital signal representative thereof. The processor operates to implement a first power management functionality and generate first power management data. At least one of a display and a communications interface couple with the processor and communicate the first power management data external to the IED. A first interface couples with the processor and the communications interface. The first interface operates to receive a first external function module. The first external function module includes a second power management functionality, where the first interface further facilitates implementation of the second power management functionality.

Patent
24 May 2004
TL;DR: In this article, a method, system and computer program for creating a digital workflow associated with the completion of a paper form is provided, which includes a panel for receiving a paper, a computer including a clipboard computer application, and an input device that completes the paper form with handwritten input data and also created digital signals corresponding to the handwritten inputs data.
Abstract: A method, system and computer program for creating a digital workflow associated with the completion of a paper form is provided. An electronic clipboard includes a panel for receiving a paper form, a computer including a clipboard computer application, and an input device that completes the paper form with handwritten input data and also created digital signals corresponding to the handwritten input data. The computer application interprets the digital signal data so as to define digital input data, which corresponds to the handwritten input data. The electronic clipboard also includes verification/correction facility that enables the display of the digital input data and verification and correction thereof using a series of input devices provided on the electronic clipboard. The electronic clipboard is linked to a remote computer. The remote computer includes a forms creation and management application for the creation of the electronic forms, and definition of rules for processing digital input data includes in the various fields of the electronic forms. In a server implementation of the invention, the remote computer is an application server that provides access to a plurality of software utilities for processing the digital input data included in the electronic forms. The application server enables processes such as financial transactions associated with electronic forms, transmission of selected digital input data to other computer systems, and field level encryption. Another aspect of the invention is a point of sale device that include the electronic clipboard.

Proceedings ArticleDOI
23 Aug 2004
TL;DR: In this paper, a phase 1 SBIR project has been conducted to develop technology for direct phase-noise measurements using fast analog-to-digital converters to digitize the input RF signal and performs all down-conversion and phase detection functions by digital signal processing.
Abstract: We have completed a phase 1 SBIR project to develop technology for direct phase-noise measurements. This new approach to phase-noise measurements uses fast analog-to-digital converters to digitize the input RF signal and performs all down-conversion and phase detection functions by digital signal processing. It has several significant advantages over analog phase-noise measurement techniques: there is no external phase-lock loop; oscillators can be compared at all different frequencies; amplitude and phase noise may be measured simultaneously; the spectrum and Allan variance may be computed simultaneously; and complex calibration techniques are eliminated.



Patent
15 Dec 2004
TL;DR: In this paper, a digital signal demodulator digitizes an OFDM signal at a sampling frequency from a sampling oscillator to produce digital OFDM signals, which are converted into I and Q components using a carrier frequency from the carrier oscillator.
Abstract: A digital signal demodulator digitizes an OFDM signal at a sampling frequency from a sampling oscillator to produce a digital OFDM signal. The digital OFDM signal is converted into I and Q components using a carrier frequency from a carrier oscillator. The IQ components are transformed into digital complex symbols, and pilot signals are extracted from the complex symbols. A processor calculates an inter-symbol difference of phase differences between pilot signals to control the sampling oscillator to correct the sampling frequency; calculates an inter-symbol difference for one of the pilot signals to control the carrier oscillator to correct the carrier frequency; and calculates a phase angle for one of the subcarriers at a frequency in the middle of the plurality of subcarriers for the OFDM signal to control the carrier oscillator to correct the carrier frequency phase.

Patent
07 Jan 2004
TL;DR: In this paper, a wideband signal generator according to one embodiment of the invention includes a variable frequency source and a direct digital synthesizer, as well as local oscillators, signal analyzers, modulators, demodulators and other equipment including one or more such generators.
Abstract: A wideband signal generator according to one embodiment of the invention includes a variable frequency source and a direct digital synthesizer. Local oscillators, signal analyzers, modulators, demodulators, and other equipment including one or more such generators are also disclosed.

Patent
04 May 2004
TL;DR: In this paper, a triple-string converter is proposed to provide a higher resolution DAC architecture for converting an N-bit digital word to a corresponding analog voltage signal without increasing chip area and switching capacitance.
Abstract: A technique to provide a higher resolution DAC architecture for converting an N-bit digital word to a corresponding analog voltage signal without increasing chip area and switching capacitance. In one example embodiment, this is accomplished by using a triple string converter. In the triple string converter, a triple switching tree is coupled to a triple resistor string and to an analog output. Each switching tree includes a plurality of switches and each resistor string includes a plurality of corresponding resistors. A logic decoder coupled to the triple switching tree receives an N-bit digital word and generates a digital signal. The plurality of switches in each switching tree is substantially simultaneously controlled by the digital signal to output a range of corresponding analog voltage signals when the triple resistor string is connected across a voltage supply.

Patent
01 Jul 2004
TL;DR: In this paper, an analog-to-digital converter samples the intermediate frequency signal and generates a digital representation thereof, and the signal output circuit receives the digital output signals from the signal processor and provides one or more output signals corresponding to the digital outputs.
Abstract: A television receiver includes a frequency conversion circuit, an analog-to-digital converter, a signal processor, and a signal output circuit. The frequency conversion circuit receives an input RF signal in one of several television signal formats and converts the input RF signal to an intermediate frequency signal. The analog-to-digital converter samples the intermediate frequency signal and generates a digital representation thereof. The signal processor processes the digital representation of the intermediate frequency signal in accordance with the television signal format of the input RF signal and generates digital output signals indicative of information encoded in the input RF signal. Finally, the signal output circuit receives the digital output signals from the signal processor and provides one or more output signals corresponding to the digital output signals. The signal output circuit can be configured to provide output signals corresponding to an analog television format or a digital television format or both.

Patent
23 Jun 2004
TL;DR: In this paper, a method for generating a refresh signal in a semiconductor device and methods for performing a refresh operation in the semiconductor memory device are disclosed, which includes measuring a temperature of the memory device, generating a temperature controlled voltage based on the measured temperature, and generating an N-bit digital signal based on a temperature-controlled voltage.
Abstract: Methods for generating a refresh signal in a semiconductor device and methods for performing a refresh operation in a semiconductor memory device are disclosed. A method for generating a refresh signal includes measuring a temperature of the semiconductor memory device, generating a temperature controlled voltage based on the measured temperature, generating an N-bit digital signal based on the temperature controlled voltage, and generating a refresh signal whose frequency is determined by the N-bit digital signal. The generation of the temperature controlled voltage includes generating a first current that is increased when the measured temperature is decreased and is decreased with the measured temperature is increased, and generating the temperature controlled voltage.