Showing papers on "Digital signal published in 1996"

Blind separation of synchronous co-channel digital signals using an antenna array. I. Algorithms

Abstract: We propose a maximum-likelihood (ML) approach for separating and estimating multiple synchronous digital signals arriving at an antenna array at a cell site. The spatial response of the array is assumed to be known imprecisely or unknown. We exploit the finite alphabet property of digital signals to simultaneously estimate the array response and the symbol sequence for each signal. Uniqueness of the estimates is established for BPSK signals. We introduce a signal detection technique based on the finite alphabet property that is different from a standard linear combiner. Computationally efficient algorithms for both block and recursive estimation of the signals are presented. This new approach is applicable to an unknown array geometry and propagation environment, which is particularly useful In wireless communication systems. Simulation results demonstrate its promising performance.

Digital baseband transmission and recording

Abstract: From the Publisher: Digital Baseband Transmission and Recording provides an integral, in-depth and up-to-date overview of the signal processing techniques that are at the heart of digital baseband transmission and recording systems. The coverage ranges from fundamentals to applications in such areas as digital subscriber loops and magnetic and optical storage. Much of the material presented here has never before appeared in book form. The main features of Digital Baseband Transmission and Recording include: -- a survey of digital subscriber lines and digital magnetic and optical storage; -- a review of fundamental transmission and reception limits; -- an encyclopedic introduction to baseband modulation codes; -- development of a rich palette of equalization techniques; -- a coherent treatment of Viterbi detection and many near-optimum detection schemes; -- an overview of adaptive reception techniques that encompasses adaptive gain and slope control, adaptive detection, and novel forms of zero-forcing adaptation; -- an in-depth review of timing recovery and PLLs, with an extensive catalog of timing-recovery schemes. Featuring around 450 figures, 200 examples, 350 problems and exercises, and 750 references, Digital Baseband Transmission and Recording is an essential reference source to engineers and researchers active in telecommunications and digital recording. It will also be useful for advanced courses in digital communications.

Digital wireless speaker system

Abstract: This invention discloses a digital wireless speaker system for use in consumer audio applications. A digital radio frequency transmitter is connected to an analog or digital audio source and a digital radio frequency receiver provides for reception of the transmitted audio information in remote locations. In addition, the digital receiver will be able to receive control information to implement such things as volume, tone controls, or other auxiliary information. This allows the user to listen to high quality audio in a variety of locations without the need of independent stereos or external wires. The system is based on digital circuitry to improve the performance of the system and provide for compact disc quality sound. The digital circuitry incorporates forward error correction techniques and interleaving to enable the system to account for errors in transmission and thus improve the overall performance of the system.

Ultrasonic diagnostic imaging system with personal computer architecture

Abstract: An ultrasonic diagnostic imaging system is provided with a personal computer platform which processes digital echo signals and produces ultrasonic image signals for display. The expansion bus structure of the personal computer platform accommodates ancillary processors such as beamformer cards, digital signal processing cards, video cards, and network cards which may be necessary or desirable for the ultrasound system. In a preferred embodiment the digital signal samples produced by a beamformer connected to the expansion bus are processed for display by software executed by the CPU of the personal computer platform. A preferred software architecture for the personal computer based ultrasound system consists of multiple object oriented software tasks, executing under a realtime, multitasking operating system which is both efficient and robust. Performance upgrades of the entire ultrasound system are effected by simple replacement of the CPU with a higher performance CPU, thus providing continual ultrasound system performance improvements in consonance with the evolution of personal computer CPU technology.

Common receive module for a programmable digital radio

Abstract: A digital submodule is included in a software programmable common receive module for receiving intermediate frequency signals and producing a serial bit stream. The digital submodule is programmable based on a selected application of a plurality of radio applications and, if present, a selected function of a plurality of functions of the selected radio application. The digital submodule may include an analog to digital converter for converting intermediate frequency signals received from an analog submodule into digital signals. The digital signals are supplied to a programmable signal processing unit which is configured, according to the selected radio application and, if present, the selected function, to perform control functions, processing and analysis of the digital signals and generate output signals. The output signals are then formatted by a formatting unit producing formatted digital signals. The formatted digital signals are then supplied to a system bus. The programmable signal processing unit may include a digital downconverter for selective use depending on the selected application of radio communication, for generating a baseband signal. Additionally, a central processing unit is included to perform further signal processing for selected radio applications.

Applications of toral automorphisms in image watermarking

Abstract: Digital watermarking methods have been proposed for various purposes and especially for copyright protection of multimedia data. The digital watermark is embedded in a digital signal or an image and must be unrecognizable by unauthorized persons and detectable only by the legal copyright owner. We use toral automorphisms as chaotic 2-D integer vector generators in order to manipulate digital image watermarking. We propose also an embedding algorithm which provides robustness under filtering and compression.

Efficient apparatus for simultaneous modulation and digital beamforming for an antenna array

Abstract: A digital beamforming network for transmitting a first number of digital information signal using a second number of antenna array elements is disclosed. Assemblers are used for assembling one information bit selected from each of the information signals into a bit vector. Digital processors have an input for the bit vector and a number of outputs equal to the second number of antenna elements and process the bit vector. Finally, modulation waveform generators coupled to each of the second number of outputs generate a signal for transmission by each antenna element.

Apparatus and method for transmitting data via a digital control channel of a digital wireless network

Abstract: A system for remotely monitoring and transmitting data and other information received from utility and other devices is disclosed. The universal meter reader of the present invention includes a device for sensing and collecting data at a first location. The sensed data that is in analog form is converted to a digital signal and a processing unit processes the data. The data is subsequently stored in a memory device for subsequent transmission to an interested party. In one embodiment, the data can be digitally transmitted over a GSM or TDMA technology digital network via a control channel. In addition, the universal meter reader includes a connective interface for connecting to a telecommunications system at a first location to establish a wireless telecommunications connection. An improved infrared reader of the present invention includes an infrared transmitter and receiver. A reflective member is displaced between the transmitter and the receiver and creates an optical communication with the rotatable disk, dial or mechanical indicator located within a conventional utility meter. The improved meter is capable of measuring the number of disk, dial or mechanical indicator rotations and is also capable of calculating and storing utility usage from the number of disk rotations. The data is then capable of being transmitted via a wired or wireless connection to the universal meter reader or a display unit.

Common transmit module for a programmable digital radio

Abstract: A common transmit module of a programmable digital radio The common transmit module has a digital submodule which receives a bit stream and produces a modulated intermediate frequency signal, and an analog submodule which receives the modulated intermediate frequency signal and converts the modulated intermediate frequency signal to a frequency corresponding to a specific type of radio function The digital submodule includes (a) a sequential/parallel instruction set processor for signal processing and control; (b) a reconfigurable format unit which is reconfigurable to produce output signals for transmitting different types of radio functions, and (c) a modulator which receives the output signals of the reconfigurable format unit and produces the modulated oscillation signal The analog submodule includes (a) a tunable local oscillator that produces a tunable local oscillation signal; (b) fixed local oscillators that produce fixed local oscillation signals; and (c) a mixing unit that receives the modulated intermediate frequency signal, the tunable local oscillation signal and the fixed local oscillation signals, selectively mixes the fixed local oscillation signals with the modulated oscillation signal to produce non-final intermediate frequency signals, and mixes a non-final intermediate frequency signal with the tunable local oscillation signal to produce a final converted signal for transmission at the frequency corresponding to the specific type of radio function

Dual-mode radiotelephone apparatus for digital or analog modulation

Abstract: A dual-mode radiotelephone capable of operation in analog or digital modes. According to exemplary embodiments, a digital signal processor receives a speech signal to be transmitted in the digital or analog mode and generates In-phase (I) and Quadrature (Q) modulating signals. The I and Q signals are supplied to a quadrature modulator for generating a digitally modulated signal and are supplied to an analog modulator for generating an analog modulated signal.

Multi-channel transceiver having an adaptive antenna array and method

Abstract: A receiver (100), transmitter (200) and transceiver (400) in accordance with the present invention overcome the disadvantages of applying adaptive antenna array technology to multi-channel communication systems. Multi-channel radio frequency (RF) signals received via an adaptive antenna array (102) are converted from an analog form to a digital form prior to splitting and processing to recover communication channels contained therein. A number of digital communication signals are digitally combined into a multi-channel digital signal and converted from the digital form to an analog radio frequency form prior to transmission from the adaptive antenna array.

Electrode connector system

Abstract: Disclosed is a physiological electrical signal connector system (20) with one connector (20a) connected to an electrode set (24) and another connector (20b) connected to a digital signal convertor (14) which leads to a patient monitor (10). Each type of electrode set has a specific code identified with it and when connected to the digital signal convertor (14), the connector code is recognized by the digital signal convertor. The connector code is then relayed to the monitor (10) which will self-configure based on the identified code.

Portable, self-contained data collection systems and methods

Abstract: A portable self-contained data collection system (100) for measuring and collecting vibration data from machines includes an accelerometer (160) which is coupled to the analog input of a data acquisition card (120). The data acquisition card (120) samples and digitizes the analog signal to produce a time domain digital signal. The data acquisition card output (122) is coupled to a battery-powered portable computer (110). The battery-powered portable computer (110) includes a database (220) having machine identifications and associated measurement parameters. The portable computer (110) processes the time domain digital signal according to the measurement parameters associated with a selected machine identification, and produces a frequency domain digital signal by performing a Fast Fourier Transform and other digital signal processing operations. The frequency domain signal is also analyzed in the portable computer (110) to produce predictive maintenance information. A power supply (150) for supplying power to the accelerometer (160) is also included. The accelerometer power supply (150) electrically and mechanically couples the accelerometer (160) to the data acquisition card (120). It supplies power to the accelerometer (160) when the data acquisition card is activated. The portable self-contained data collection system (100) can be used to measure and collect vibration data from machines and to analyze this data to produce predictive maintenance information.

Conversion circuit for process control system

Abstract: Conversion circuitry (40) for use in a process control system (10) is adapted for coupling to a primary process control loop (26). Digital receiver circuitry (46, 52) in the conversion circuitry (40) receives a digital signal transmitted over the primary process control loop (26) from a field transmitter (22) and responsively provides a digital output. A microprocessor (50) receives the digital output and responsively provides a secondary loop control output. Secondary loop control circuitry (62) for coupling to a secondary process control loop (58) receives the secondary loop control output from the microprocessor (50) and responsively controls current flowing through the secondary process control loop (58). The current flowing through the secondary process control loop (58) is related to the digital signal transmitted by the field transmitter (22).

Binaural signal processing system and method

Abstract: A desired acoustic signal is extracted from a noisy environment by generating a signal representative of the desired signal with a processor for a hearing aid device. The processor receives binaural signals from two microphones at different locations. The binaural inputs to the processor are converted from analog to digital format and then submitted to a discrete Fourier transform process to generate discrete spectral signal representations. The spectral signals are delayed by a number of time intervals in a dual delay line to provide a number of intermediate signals, each corresponding to a different position relative to a desired signal source. Location of the noise source is determined and the spectral content of the desired signal is determined from the intermediate signal corresponding to the noise source location. Inverse transformation of the selected intermediate signal followed by digital to analog conversion provides an output signal representative of the desired signal.

Memory management for an MPEG2 compliant decoder

Abstract: Disclosed is a digital signal decoder system for receiving compressed encoded digitized video signals and transmitting decompressed decoded digital video signals. This is accomplished with a minimum of DRAM demand through the use of a Spill Buffer.

Am compatible digital waveform frame timing recovery and frame synchronous power measurement

Abstract: In a broadcast system having a complex waveform of digital and analog segments, frame timing is recovered (290) and the frame synchronous power (284) of the digital portion of the composite AM compatible Digital Audio Broadcast (DAB) waveform is measured by examining a portion of the signal (284) The frame timing necessary for proper demodulation is recovered from the received signal (200), and a signal power measurement for scaling (242) is provided (294) The composite AM compatible DAB waveform is produced by a modulation method in which a digital representation of an audio signal is encoded together with an analog amplitude modulated (AM) signal and transmitted simultaneously in the same frequency channel

A Digital Signal Processing Primer: With Applications to Digital Audio and Computer Music

Abstract: a digital signal processing primer with applications to digital signal processing primer with applications to digital signal processing primer with applications to a digital signal processing primer with applications to a digital signal processing primer with applications to digital signal processing the computer laboratory digital signal processing the computer laboratory digital signal processing cems home signal processing ece, rutgers ece 431 digital signal processing lecture notes signals and systems, 1997, 957 pages, alan v. oppenheim toyota repair manual browserfame balboa lite digital system manual towies pharmacotherapy in primary care browserfame tiger products co ltd user manual foserv digital signal processing for audio applications vbou q a revision guide evidence 2013 and 2014 law questions digital audio signal processing ku leuven electrical,electronics,communications,power,precision and advances in silicon carbide processing and applications document about student solutions manual for stewarts repair manual cp99 saosey applications of minicomputers to library and related problems multiple choice questions on obstetric nursing ebook | www elvis presley a biography auzww close to home a book of postcards zaraa computer controlled urban transportation gurka munch und deutschland boscos a sounding brass elect trilogy 3 zaraa a biographical history of the french revolution trupin gurps y2k the countdown to armageddon gurps ser generic new treasury of poetry oilys nv53 service manual saosey hp 7310xi manual subiuk early readers level 2 xcelr birding the front range awandc the heart of parenting raising an emotionally intelligent 1987 crusader engine manual fakof letters from rising pharmacy starsadvice on creating and 2010 nissan pathfinder service repair manual beelo essays on race and empire mdmtv solomon goldbard v empire state mutual life insurance co melancholie der ankunft blwood nissan bluebird manual mdmtv simulation and analysis of audio signal processor ijca yamaha outboard f115 lf115 factory service repair workshop

GPS ready digital cellular telephone

Abstract: A cellular telephone system has an antenna (12,18) for receiving a location system signal such as GPS and a cellular signal, a location system receiver (10) coupled to the antenna (12), a mobile radio telephone transceiver (16), such as digital cellular, coupled to the antenna (18), and a processor (14) coupled to the global positioning system receiver (10) and to the cellular telephone transceiver (16). The global positioning system receiver employs a GPS demodulator (24,48) for demodulating a first position signal, a second position signal, and a third position signal from first, second and third earth orbit satellites (34,30,38). The cellular telephone transceiver (16) employs a receive channel (58) for demodulating an incoming portion of the cellular signal and generating an incoming intermediate frequency signal in response thereto, and a transmit channel (64) for modulating an outgoing intermediate frequency signal and for generating an outgoing portion of the cellular signal in response thereto. In addition, the cellular telephone transceiver (16) employs an interface circuit (62) for converting the incoming intermediate frequency signal and for converting an outgoing digital signal. The processor (14) determines (14) an approximate location of the cellular telephone system, encodes (14) an outgoing voice information signal, and decodes (14) the incoming intermediate frequency signal.

Digital testing of analog memory devices

Abstract: An analog memory has comparison logic and a reference voltage generator built on-chip for testing of analog write and read processes. During a test, the reference voltage generator, which may be a resistor tree structure, provides a set of intermediate voltages. One of the intermediate voltages V IN is written to a selected memory cell. The comparison logic compares other intermediate voltages V H and V L to an analog output signal generated by reading the selected memory cell. A digital control signal from an external digital tester selects the levels of voltages V IN , V H , and V L . Typically, voltages V H and V L are equal V IN ±ΔV where ΔV represents an acceptable resolution for stored analog data. If the signal from reading the selected memory cell falls within a desired range V IN ±ΔV, an output digital result signal is set; otherwise, the test result signal is cleared. A low-cost digital tester which generates the digital control signals and observes the digital result signal can test all the circuits associated directly with write and read processes. Since the analog signals for the test are generated on-chip, the effect of noise is minimized, and a high accuracy resolution test is achieved.

Portable information terminal apparatus having image processing function

Abstract: A portable terminal apparatus provided with an image processing function permitting automatic image-pickup without manual focusing which includes an optical system for forming an optical image of a surface of a subject, a two-dimensional photoelectric conversion element for performing photoelectric conversion onto the formed optical image, a signal conversion device for converting an output signal of the photoelectric conversion element into a digital signal, a memory device for temporarily storing the two-dimensional image signal digitized by the signal conversion device, a subject position detecting device storing the optimum image-formation distance of the optical system in advance and for detecting the distance between the subject and the optical system, and an image inputting device including an electronic shutter device which supplies a video signal on the two-dimensional photoelectric conversion element to the memory device to hold the video signal in the memory device instantaneously when the subject position detecting device detects that the subject is located at an image-forming distance.

The effect of quantization in a digital signal component separator for LINC transmitters

Abstract: Spectrally efficient modulation schemes have been chosen for the second generation of cellular systems in the United States and Japan, as well as for private mobile radio (PMR) systems This paper analyzes the effect of quantization in a digital signal component separator (SCS) for linear amplification with nonlinear components (LINC) transmitters The analysis relies on the fact that the two signal components can be obtained as the source signal plus/minus a signal in quadrature to the source signal The equations derived are vital because they allow the designer to optimize digital signal processor (DSP) power consumption and bandwidth The word lengths that are required for the source signal and the quadrature signal can be calculated from the amplifier gain characteristic, the probability density function for the modulation scheme, and the specified adjacent channel interference (ACI) The validity of the analysis has been verified by means of simulations

Fingerprint detector using ridge resistance sensing array

Abstract: A fingerprint detector that uses a skin resistance sensing array for producing a sample trajectory signal when a fingertip is moved across the sensing array surface. The sample trajectory signal represents the electrical conductance changes in the resistance of ridges and valleys of the fingertip. The fingerprint detector also includes a sampling circuit coupled to a processor. In addition, a technique is disclosed for detecting and verifying a fingerprint by moving a fingertip relative to the skin resistance sensing array. The sample trajectory signal produced is translated into a digital signal by the sampling circuit. The processor receives the digital sample trajectory signal for comparison with a known reference trajectory signal. The processor produces a verification signal if a threshold probability that the same fingertip generated both signals is exceeded. The reference trajectory signal is stored in a memory integrated into the device, or is provided from an external storage device through a data interface.

Digital alias-free signal processing in the GHz frequency range

Abstract: The advanced Information Technology we call Digital Alias-free Signal Processing (DASP) is discussed in this paper to draw attention to the facts that, first, this technique has already reached a considerable degree of maturity so that it can now be used as a widely applicable Digital Signal Processing (DSP) tool and, second, that it is especially competitive in the area of Microwave and Radio Frequency (RF) signal processing. Its utility arises from its applicability to digital processing of signals at frequencies considerably exceeding half of the mean sampling rate, which traditionally limit classical DSP applications.

Method and apparatus for receiving and / or reproducing digital signals

Abstract: A method and apparatus is provided for receiving and/or reproducing a digital signal, capable of efficiently recording a compressed, packeted digital signal (170-173) and inhibiting a copy thereof. An input packet signal is added (Fig. 9) with a time stamp indicating a relative time of an arrival of the packet, and the packet signals of digital information with the added time stamps are recorded at reduced intervals (Fig. 8(3)) therebetween. In reproducing, a packet interval adjusting circuit (Fig. 11) restores the original packet intervals in accordance with the time stamps, and then a time stamp change circuit (Fig. 9) changes at least one bit of the time stamp and thereafter outputs the digital information.

Method for universal messaging and multiplexing of video, audio, and data streams

Abstract: A method is disclosed for supplying arbitrary types of information in a digital signal conformant to the structures defined in ISO standard ISO/IEC 13818-1, known generally as MPEG2 Systems. The method extends Program Stream and Transport Stream structures by application of principles developed for standardization of bidirectional data communications protocols to define a universal messaging syntax applicable to all types of information, including Internet data streams, VBI data streams, other types of data streams, as well as MPEG2 video, audio, and control; to define a multiplexing structure that is independent of the details of the MPEG2 signal structure; and to define a scheme for addressing such enhanced MPEG2 signals, or portions of signals, to individual decoders or to groups of decoders.

Data communication method

Abstract: It is an object of the present invention to reduce the number of terminals in an equipment for inputting or outputting a realtime digital signal such as a digital audio signal and a music/musical instrument signal. A first converter and a second converter are provided with a function of mutual conversion between a signal format of a digital audio interface and a signal format of IEEE-1394. For example, it is possible to transmit a signal of a digital audio interface outputted from a first CD player to the first converter, to convert the signal here into a packet of IEEE-1394 isochronous transmission format and transmit it to the second converter, and to return the packet to the digital audio interface and record a digital audio signal in an MD recorder. When a converter having a function of mutual conversion between the MIDI signal format and the IEEE-1394 signal format is provided, it is also possible to perform bidirectional data communication among a plurality of MIDI musical instruments.

Digital automatic gain control employing two-stage gain-determination process

Abstract: For use in an automatic gain control that receives a digital signal from a digital circuit having a given dynamic range and develops therefrom a gain signal to be applied to a variable gain amplifier, an analyzing circuit for, and method of, determining a magnitude of the gain signal. The analyzing circuit includes: (1) a peak sampling subcircuit that determines an average peak value of the digital signal over variable periods of time and (2) a gain signal adjustment subcircuit, coupled to the peak sampling subcircuit, that operates in a selected one of: (a) a search mode in which the gain signal adjustment subcircuit decreases the periods of time and adjusts the gain signal at a first rate until the average peak value falls within the dynamic range of the digital circuit and (b) a direct step mode in which the gain signal adjustment subcircuit increases the periods of time and adjusts the gain signal at a second rate as a function of a deviation of the average peak value from a target average peak value, the first rate being faster than the second rate, the analyzing circuit thereby applying a two-stage gain determination process to the digital signal to approach the target average peak value.

Radio communication system

Abstract: A CW (Continuous Wave) radio frequency signal converted to an IF (Intermediate Frequency) signal is mixed with a local oscillator signal by an IF mixer, and the obtained signal is converted to a digital signal by an ADC (Analog-to-Digital Converter). A digital bandpass filter passes only the target component in the output of the ADC. The passed IF signal is demodulated by a digital demodulator, and the demodulated signal is converted to an analog signal before being output as a sound. When pitch control to increase the reception pitch by DELTA f is instructed, an MPU (Microprocessor Unit) alters the frequency of the local oscillator signal by DELTA f as well as the center frequency of the digital bandpass filter by DELTA f, so that the center frequency of the input signal to a narrow-band filter coincides with the center frequency of the digital bandpass filter.

Digital feed-forward active noise control system

Abstract: A method of noise control of an acoustic signal comprising: obtaining a reference signal (X) of the acoustic signal to be controlled, applying an antinoise signal to the acoustic signal so as to control the acoustic signal, obtaining an error signal (E) resulting from the application of the antinoise signal (U) to the acoustic signal, generating the antinoise signal from the reference signal by passing the noise signal through a first filter (33) having controllable filter coefficients, using a simplified model (31) of a signal path from a location (19) of the antinoise signal to a location (21) of the error signal to obtain modified representations of the noise signal, controlling the filter coefficients by processing the error signal and the modified representation of the noise signal and generating a coefficient control signal (35) such as to generate the antinoise signal, and applying the coefficient control signal to the first filter.