Showing papers on "Digital signal published in 2012"

Optical filter for image and barcode scanning

Abstract: Methods for using an optical indicia reading terminal including a housing, a multiple pixel image sensor disposed within the housing, an imaging lens assembly configured to focus an image of decodable indicia on the image sensor, an optical bandpass filter disposed in an optical path of light incident on the image sensor, an analog-to-digital (A/D) converter configured to convert an analog signal read out of the image sensor into a digital signal representative of the analog signal, and processor configured to output a decoded message data corresponding to the decodable indicia by processing the digital signal.

Decodable indicia reading terminal with optical filter

Abstract: A decodable indicia reading terminal can comprise a housing including a housing window, a multiple pixel image sensor disposed within the housing, an imaging lens configured to focus an image of decodable indicia on the image sensor, an optical bandpass filter disposed in an optical path of light incident on the image sensor, an analog-to-digital (A/D) converter configured to convert an analog signal read out of the image sensor into a digital signal representative of the analog signal, and processor configured to output a decoded message data corresponding to the decodable indicia by processing the digital signal.

Design and characterization of a 256x64-pixel single-photon imager in CMOS for a MEMS-based laser scanning time-of-flight sensor

Abstract: We introduce an optical time-of-flight image sensor taking advantage of a MEMS-based laser scanning device. Unlike previous approaches, our concept benefits from the high timing resolution and the digital signal flexibility of single-photon pixels in CMOS to allow for a nearly ideal cooperation between the image sensor and the scanning device. This technique enables a high signal-to-background light ratio to be obtained, while simultaneously relaxing the constraint on size of the MEMS mirror. These conditions are critical for devising practical and low-cost depth sensors intended to operate in uncontrolled environments, such as outdoors. A proof-of-concept prototype capable of operating in real-time was implemented. This paper focuses on the design and characterization of a 256 x 64-pixel image sensor, which also comprises an event-driven readout circuit, an array of 64 row-level high-throughput time-to-digital converters, and a 16 Gbit/s global readout circuit. Quantitative evaluation of the sensor under 2 klux of background light revealed a repeatability error of 13.5 cm throughout the distance range of 20 meters.

A Low-Power Level Shifter With Logic Error Correction for Extremely Low-Voltage Digital CMOS LSIs

Abstract: This paper presents a level shifter circuit capable of handling extremely low-voltage inputs. The circuit has a distinctive current generation scheme using a logic error correction circuit that works by detecting the input and output logic levels. The proposed level shifter circuit can convert low-voltage digital input signals into high-voltage digital output signals. The circuit achieves low-power operation because it dissipates operating current only when the input signal changes. Measurement results demonstrated that the circuit can convert a 0.23-V input signal into a 3-V output signal. The power dissipation was 58 nW for a 0.4-V 10-kHz input pulse.

Animal Acoustic Communication: Sound Analysis and Research Methods

Abstract: Chapter 1 Acoustic Signals of Animals: Recording, Field Measurements, Analysis and Description H. C. Gerhardt 1 Introduction 2 Field Recordings and Measurements 2.1 Equipment 2.2 On-Site Measurements 2.3 Signal Amplitude, Directionality, and Background Noise Levels 2.4 Patterns of Sound Propagation in Natural Habitats 3 Laboratory Analysis of Animal Sounds 3.1 Terminology 3.2 Temporal and Spectral Analysis: Some General Principles 4 Examples of Descriptions and Analyses 4.1 Temporal Properties of Pulsatile Calls 4.2 Amplitude-Time Envelopes 4.3 Relationships between Fine-Scale Temporal and Spectral Properties 4.4 Spectrally Complex Calls 5 Summary References.- Chapter 2 Digital Signal Acquisition and Representation M. Clements 1 Introduction 2 Digital Signal Processing 2.1 Major Applications of DSP 2.2 Definition of Digital Systems 2.3 Difference Equations 3 Digital Filter Frequency Response 3.1 Unit-Sample Response Characterization 3.2 Frequency-Domain Interpretation of Systems 3.3 Frequency-Domain Interpretation of Signals 4 Conversion Between Analog and Digital Data Forms 4.1 The Sampling Theorem 4.2 Signal Recovery by Filtering 4.3 Fourier Transform Relations 4.4 Effects of Sampling Rates 4.5 Reconstruction 5 Fundamental Digital Processing Techniques 5.1 Power Spectra 5.2 Time and Frequency Resolution 5.3 Windows 5.4 Spectral Smoothing 5.5 The Discrete Fourier Transform 5.6 Correlation 5.7 Autocorrelation 5.8 Cross-correlation 5.9 Spectrograms 6 An Intoduction to Some Advanced Topics 6.1 Digital Filtering 6.2 Linear Prediction 6.3 Homomorphic Analysis 7 Summary.- Chapter 3 Digital Signal Analysis, Editing, and Synthesis K. Beeman 1 Introduction 2 Temporal and Spectral Measurements 3 Time-Varying Amplitude Analysis 3.1 Amplitude Envelopes 3.2 Gate Functions 4 Spectral Analysis 4.1 Power Spectrum Features 4.2 Measuring Similarity Among Power Spectra 4.3 Other Spectral Analysis Techniques 5 Spectrographic Analysis 5.1 Spectrogram Generation 5.2 Spectrogram Display 5.3 Spectrogram Parameter Measurements 6 Classification of Naturally Occurring Animal Sounds 6.1 Properties of Ideal Signals 6.1.1 Periodicity 6.1.2 Amplitude Modulation 6.1.3 Frequency Modulation 6.1.4 Biologically Relevant Sound Types 7 Time-varying Frequency Analysis 7.1 Deriving Spectral Contours 7.2 Sound-similarity Comparison 8 Digital Sound Synthesis 8.1 Editing 8.2 Arithmetic Manipulation and Generation of Sound 8.3 Synthesis Models 8.3.1 Tonal Model 8.4 Sources of and A Functions 8.4.1 Mathematically Based Functions 8.4.2 Functions Derived from Natural Sounds 9 Sound Manipulation and Generation Techniques 9.1 Duration Scaling 9.2 Amplitude-Envelope Manipulations 9.3 Spectral Manipulations 9.3.1 Frequency Shifting and Scaling 9.3.2 Frequency Modulation 9.4 Synthesis of Biological Sound Types 9.4.1 Tonal and Polytonal Signals 9.4.2 Pulse-Repetition Signals 9.4.3 Harmonic Signals 9.4.4 Noisy Signals 9.5 Miscellaneous Synthesis Topics 9.5.1 Template Sounds 9.5.2 Noise Removal 10 Summary References.- Chapter 4 Application of Filters in Bioacoustics P. K. Stoddard 1 Introduction 2 General Uses of Filters and Some Cautions 3 Anatomy and Performance of a Filter 4 Properties of Various Analog Filters 5 Antialiasing and Antiimaging Filters 5.1 A/D Conversion Requires an Analog Lowpass Filter 5.2 Choosing an Antialiasing Filter 5.3 D/A Conversion also Requires an Analog Lowpass Filter 5.4 Analog Filters: Passive Versus Active Components 6 Analog Versus Digital Filters

Digital signal routing circuit

Abstract: An integrated circuit for digital signal routing. Signal routing is achieved by means of a multiply-accumulate block, which takes data from one or more data source and, after any required scaling, generates output data for a data destination. The multiply-accumulate block operates on a time division multiplexed basis, so that multiple signal paths can be processed within one period of the sample clock. Each signal path has a respective sample clock rate, and paths with different sample clock rates can be routed through the multiply-accumulate block on a time division multiplexed basis independently of each other. Thus, speech signals at 8 kHz or 16 kHz can be processed concurrently with audio data at 44 kHz or 48 kHz.

Self-mixing vibrometer with real-time digital signal elaboration.

Abstract: This work describes the development of an optical sensor for measurement of vibration without contact. The realized vibrometer is based on real-time digital elaboration of the signal obtained by a self-mixing interferometer, with an embedded autofocus system. Two different algorithms are implemented, for the continuous working on diffusive surfaces, with different levels of optical reflectivity. Thanks to the autofocus and the digital processing, the proposed sensor is easy to use and requires no assistance of a skilled operator.

Experimental demonstration of a format-flexible single-carrier coherent receiver using data-aided digital signal processing

Abstract: We experimentally demonstrate the use of data-aided digital signal processing for format-flexible coherent reception of different 28-GBd PDM and 4D modulated signals in WDM transmission experiments over up to 7680 km SSMF by using the same resource-efficient digital signal processing algorithms for the equalization of all formats. Stable and regular performance in the nonlinear transmission regime is confirmed.

Multi-Mode Operation and Control of a Resonant Converter

Abstract: In accordance with an embodiment, a method of controlling a switched-mode power includes generating a feedback signal proportional to an output of the switched-mode power supply, and operating the switched-mode power supply in a normal mode. If the feedback signal crosses a first threshold, the switched-mode power operates in a second operating mode. In the first operating mode the pulse modulated signal is adjusted to regulate a feedback signal to a first signal level, and in the second operating mode, a dead-time of the pulse modulated signal is adjusted to signal to regulate a feedback signal to a second signal level different from the first signal level. The method further includes driving a switch of the switched-mode power supply with the pulse modulated signal.

Evolved distributed antenna system

Abstract: One embodiment is directed to a distributed antenna system (DAS) including a host unit and a plurality of remote units. The host unit includes a plurality of base transceiver stations and a switch. Each of the base transceiver stations is configured to provide a downstream baseband digital signal to the switch and to receive an upstream baseband digital signal from the switch, wherein each downstream baseband digital signal and upstream baseband digital signal is a digital representation of the RF channel at baseband of the respective base transceiver station. The switch is configured to route each of the downstream baseband digital signals to a respective subset of the remote units as one or more downstream serial data streams and to route each of the upstream baseband digital signals from one or more upstream serial data streams to a respective subset of the base transceiver stations.

Method of transmitting a digital signal for a semi-orthogonal ms-marc system, and a corresponding program product and relay device

Abstract: A method for semi-orthogonal transmission of a signal intended for a system with N sources, M relays and a single receiver whereby the simultaneous transmission on a same spectral resource by the relays is successive and not simultaneous to a simultaneous transmission on a same spectral resource by the sources. The includes, by relay: joint iterative detection/decoding of messages transmitted respectively by the sources to obtain decoded messages, detecting errors on the decoded messages, interleaving the detected messages without errors followed by algebraic network coding consisting of a linear combination in a finite group of an order strictly higher than two of the interleaved messages to obtain a coded message, the linear combinations being independent, two by two, between the relays of the system, and formatting including channel coding to generate a signal representative of the network coded message.

Intelligent device system and method for distribution of digital signals on a wideband signal distribution system

Abstract: A plurality of intelligent device systems for use with a wideband signal distribution network, and methods for transmitting digital information and receiving digital and non-digital information onto and off of an RF carrier through a wideband signal distribution network, are disclosed. The intelligent device systems provide networks of intelligent devices that modulate and demodulate digital video, IP video/data/voice and digital wireless onto, and off of, a wideband signal distribution system, such as an analog carrier system, using existing EIA/TIA 568 standard wiring infrastructure. The methods modulate and demodulate digital video, IP video/data/voice and digital wireless onto, and off of, a wideband distribution system, such as an analog carrier system, and separate IP portions from non-IP portions.

Semi-physical simulation testing platform of train control network

Abstract: The invention discloses a semi-physical simulation testing platform of a train control network, which comprises a vehicle-mounted electrical control system, a software simulation control system and/or a physical control system and a data acquisition interactive system, wherein the software simulation control system and/or the physical control system is connected with the vehicle-mounted electrical control system; the data acquisition interactive system is connected with the vehicle-mounted electrical control system so as to convert a signal output by the vehicle-mounted electrical control system into a digital signal or convert the digital signal into an input signal required by the vehicle-mounted electrical control system; and the data acquisition interactive system is connected with the software simulation control system and/or the physical control system so as to convert the digital signal connected and output by the software simulation control system and/or the physical control system into a switching value signal or convert the switching value signal into the digital signal required by the software simulation control system and/or the physical control system. The semi-physical simulation testing platform of the train control network is capable of comprehensively implementing evaluation and verification on the design of a train network control system, eliminating possibledesign errors, rapidly positioning faults to ask for reasons, and reducing the production debugging cost and the technical risks of real trains.

Distributed antenna system interface for processing digital signals in a standardized format

Abstract: An interface is provided for processing digital signals in a standardized format in a distributed antenna system. One example includes a unit disposed in a distributed antenna system. The unit includes an interface section and an output section. The interface section is configured for outputting a first complex digital signal and a second complex digital signal. The first complex digital signal is generated from a digital signal in a standardized format received from a digital base station. The output section is configured for combining the first complex digital signal and the second complex digital signal into a combined digital signal. The output section is also configured for outputting the combined digital signal. The combined digital signal comprises information to be wirelessly transmitted to a wireless user device.

System and method for full duplex cancellation

Abstract: Disclosed herein are systems, methods, and computer-readable storage media for enabling improved cancellation of self-interference in full-duplex communications, or the transmitting and receiving of communications in a single frequency band without requiring time, frequency, or code divisions. The system estimates the signal strength and phase of a self-interference signal, generates a cancellation signal based on this estimate, then uses the cancellation signal to suppress the self-interference before sampling received analog signal. After applying the cancellation signal, the system samples and digitizes the remaining analog signal. The digitized signal is then subjected to additional digital cancellation, allowing for extraction of the desired signal.

Interposer based imaging sensor for high-speed image acquisition and inspection systems

Abstract: The present invention includes an interposer disposed on a surface of a substrate, a light sensing array sensor disposed on the interposer, the light sensing array sensor being back-thinned and configured for back illumination, the light sensing array sensor including columns of pixels, one or more amplification circuitry elements configured to amplify an output of the light sensing array sensor, the amplification circuits being operatively connected to the interposer, one or more analog-to-digital conversion circuitry elements configured to convert an output of the light sensing array sensor to a digital signal, the ADC circuitry elements being operatively connected to the interposer, one or more driver circuitry elements configured to drive a clock or control signal of the array sensor, the interposer configured to electrically couple at least two of the light sensing array sensor, the amplification circuits, the conversion circuits, the driver circuits, or one or more additional circuits.

Robot continuous sound source positioning method

Abstract: The invention discloses a robot continuous sound source positioning method which comprises the following steps of: (1) acquiring a sound source signal by adopting a microphone array consisting of at least two pairs of microphones, converting the signal into a digital signal and storing the signal by a robot; and (2) carrying out effective audio signal detection on the acquired signal and carrying out sound source positioning operation on the signal containing effective audio frequency to obtain the position of a sound source relative to the robot. The method disclosed by the invention can divide the frequency domain signal obtained after Fourier transformation as for different application scenes and the frequency characteristic and noise characteristic of the sound source when the method is applied into a sound source positioning system of the robot and the calculating capability of the robot is limited, and thereby, the positioning operation time of the robot is greatly reduced, and the positioning speed is high. Meanwhile, as for the characteristic of movement of the robot, after the displacement angle is subjected to motion modification, the accuracy and instantaneity of positioning are greatly improved.

Event-Driven GHz-Range Continuous-Time Digital Signal Processor With Activity-Dependent Power Dissipation

Abstract: Presented is a clockless, continuous-time (CT) GHz processor that bypasses some of the limitations of conventional digital and analog implementations. Per-edge digital signal encoding is used for parallel processing of continuous-time samples with a temporal spacing as narrow as 15 ps, generated by a 3-b CT flash ADC. Parallel digital delay chains and programmable charge pumps realize the asynchronous filtering operation, each consuming negligible power while awaiting a new sample. A six-tap CT ADC and CT digital FIR processor system occupies 0.07 mm2 and achieves dynamic range of over 20 dB in the 0.8-3.2-GHz signal range. The system's rate of operations automatically adapts to the signal, thus causing its power dissipation to vary in the range of 1.1 to 10 mW according to input activity.

A study of digital image watermarking

Abstract: Watermarking is a very important field for copyrights of various electronic documents and media. With images widely available on the Internet, it may sometimes be desirable to use watermarks. Digital watermarking is the processing of combined information into a digital signal. A watermark is a secondary image, which is overlaid on the host image, and provides a means of protecting the image. It acts as a digital signature, giving the image a sense of ownership or authenticity. Digital watermarking technique is very impressive for image authentication or protection for attacks. In this paper we aim to present a survey on different types of digital watermarks and methods to do image watermarking. Problems and challenges to produce watermarked images are also analyzed and reported.

Design and Simulation of 32-Point FFT Using Radix-2 Algorithm for FPGA Implementation

Abstract: The Fast Fourier Transform (FFT) is one of the rudimentary operations in field of digital signal and image processing. Some of the very vital applications of the fast fourier transform include Signal analysis, Sound filtering, Data compression, Partial differential equations, Multiplication of large integers, Image filtering etc. Fast Fourier transform (FFT) is an efficient implementation of the discrete Fourier transform (DFT). This paper concentrates on the development of the Fast Fourier Transform (FFT), based on Decimation-In-Time (DIT) domain, Radix-2 algorithm, this paper uses VHDL as a design entity, and their Synthesis by Xilinx Synthesis Tool on Vertex kit has been done. The input of Fast Fourier transform has been given by a PS2 KEYBOARD using a test bench and output has been displayed using the waveforms on the Xilinx Design Suite 12.1. The synthesis results show that the computation for calculating the 32-point Fast Fourier transform is efficient in terms of speed.

Adaptive interference canceller in a digital phase array

Abstract: A digital phased array may include a plurality of antenna elements forming a main array of the digital phased array, a plurality of mixers configured to down-convert data received at respective ones of the antenna elements, a plurality of analog-to-digital converters configured to digitize data provided by corresponding ones of the mixers, and a digital signal processor. The digital signal processor may be configured to receive digitized data including at least one interference signal and at least one desired signal, determine an angle of arrival of the at least one interference signal, steer a beam of the main array toward the at least one interference signal based on the determined angle of arrival, and perform interference cancellation relative to the at least one interference signal.

Systems, circuits, and methods for a sigma-delta based time to digital converter

Abstract: Systems, methods, and circuits provide a time to digital converter comprising a sigma-delta modulator. The sigma-delta based time to digital converter may receive an analog signal representing a phase error between a reference clock signal and a feedback clock signal and generate a digital signal representing the phase error. The sigma-delta modulator may comprise a subtractor, an integrator, a feedback path, and a quantizer. The subtractor may receive the analog signal and subtract a feedback signal from the analog signal and the integrator may integrate the output of the subtractor. The sigma-delta modulator may accumulate a voltage or a charge over a capacitor as pulses are received from the analog signal and after a number of clock cycles, the capacitor may be discharged to generate a pulse in an output signal.

Low power radio frequency to digital receiver

Abstract: A radio frequency to digital receiver has a modulator sampling a signal at a first rate. The receiver has at least one processing unit. The processing unit has a plurality of digital bandpass filters separating the signal and recombining the signal at a rate less than the first rate. The processing unit has a digital down converter adjusting frequency offset or centering the signal at the rate less than the first rate. The receiver has at least one rate control buffer coupled to adjacent processing units when two or more processing units are within the receiver.

Sleeping heart rate and breath monitoring system

Abstract: The utility model relates to a sleeping heart rate and breath monitoring system which comprises one or a plurality of sensors, a preprocessing circuit, a wireless transmission module, a data analysis processing module and a carrier, wherein the sensor is used for acquiring a body surface motion signal and/or a force application signal of a surface body for the outside of a human body in a sleeping state, which comprises heartbeat information and/or breathing information; the preprocessing circuit is used for preprocessing the motion and/or force application signal into an original digital signal which is suitable for transmission and comprises a heartbeat signal and/or a breathing signal; the wireless transmission module is used for transmitting the original digital signal by a wireless transmission mode; the data analysis processing module is used for analyzing and processing the original digital signal to obtain heart rate and/or breathing rate data; the carrier is used for fixing the sensor; and the sensor and the preprocessing circuit are arranged in an integrated or separate mode. The sleeping heart rate and breath monitoring system is convenient to use, has high measurement reliability and does not influence the sleeping of a user.

A microcontroller-based lock-in amplifier for sub-milliohm resistance measurements.

Abstract: This paper presents a novel approach to the design of a digital ohmmeter with a resolution of <60 μΩ based on a general-purpose microcontroller and a high-impedance instrumentation amplifier only. The design uses two digital I/O-pins to alternate the current through the sample resistor and combined with a proper firmware routine, the design is a lock-in detector that discriminates any signal that is out of phase/frequency with the reference signal. This makes it possible to selectively detect the μV drop across sample resistors down to 55.6 μΩ using only the current that can be supplied by the digital output pins of a microcontroller. This is achieved without the need for an external reference signal generator and does not rely on the computing processing power of a digital signal processor.

Compact, low cost raman monitor for single substances

Abstract: Apparatus for performing Raman analysis may include a laser source module, a beam delivery and signal collection module, a spectrum analysis module, and a digital signal processing module. The laser source module delivers a laser beam to the beam delivery and signal collection module. The beam delivery and signal collection module delivers the laser source beam to a sample, collects Raman scattered light scattered from the sample, and delivers the collected Raman scattered light to the spectrum analysis module. The spectrum analysis module demultiplexes the Raman scattered light into discrete Raman bands of interest, detects the presence of signal energy in each of the Raman bands, and produces a digital signal that is representative of the signal energy present in each of the Raman bands. The digital signal processing module is adapted to perform a Raman analysis of the sample.

A wireless surveillance and safety system for mine workers based on Zigbee

Abstract: This paper addresses a cost-effective, flexible solution of underground mine workers' safety. A module of MEMS based sensors are used for underground environment monitoring and automating progression of measurement data through digital wireless communication technique is proposed with high accuracy, smooth control and reliability. A microcontroller is used for collecting data and making decision, based on which the mine worker is informed through alarm as well as voice system. The voice system with both microphone and speaker, transforms into digital signal and effectively communicate wirelessly with the ground control centre computer. ZigBee, based on IEEE 802.15.4 standard is used for this short distance transmission between the hardware fitted with the mine worker and the ground control centre.

Modulation technique for transmitting and receiving radio vortices

Abstract: A device for generating Orbital Angular Momentum (OAM) modes for radio communications. The device is designed to receive one or more input digital signals, each of which has a respective sampling period which is a respective multiple of a given sampling period, and occupies a frequency bandwidth which is a respective fraction of a given available frequency bandwidth. The device is operable to apply, to each input digital signal, a respective space modulation associated with a respective OAM mode having a respective topological charge to generate a corresponding digital signal carrying the respective OAM mode. The device is configured to apply, to each input digital signal, the respective space modulation by interpolating said input digital signal and phase-modulating the interpolated input digital signal so as to generate a corresponding phase-modulated digital signal carrying the respective OAM mode, having the given sampling period, and occupying the given available frequency bandwidth.

Digital to analog converter

Abstract: The invention provides a digital-to-analog converter comprising a thermometer encoder, a random clock dynamic element matching module and a current source array, wherein the thermometer encoder is used for converting an input digital signal code stream into a thermometer code; the current source array is used for outputting an analog signal; the random clock dynamic element matching module is connected with the thermometer encoder and the current source array and provided with a random clock for generating a random clock signal and a current source channel array for transmitting the thermometer code; and the random clock dynamic element matching module alternates the ranking position of the thermometer code in the current source channel array according to the random clock signal and outputs a thermometer code control signal to the current source array according to the ranking position of the thermometer code. In the digital-to-analog converter, a random clock is introduced by the random clock DEM (dynamic element matching) module, therefore the use of a large quantity of randomized modules is avoided, and the effects of reducing the cost of realizing hardware for a circuit and improving the digital-to-analog conversion efficiency are achieved.