Showing papers on "Encoder published in 1976"

Bit allocation and encoding for vector sources

Abstract: This paper considers the problem of efficient transmission of vector sources over a digital noiseless channel. It treats the problem of optimal allocation of the total number of available bits to the components of a memoryless stationary vector source with independent components. This allocation is applied to various encoding schemes, such as minimum mean-square error, sample-by-sample quantization, or entropy quantization. We also give the optimally decorrelating scheme for a source whose components are dependent and treat the problems of selecting the optimum characteristic of the encoding scheme such that the overall mean-squared error is minimized. Several examples of encoding schemes, including the ideal encoder that achieves the rated istortion bound, and of sources related to a practical problem are discussed.

Experiments in text file compression

Abstract: A system for the compression of data files, viewed as strings of characters, is presented. The method is general, and applies equally well to English, to PL/I, or to digital data. The system consists of an encoder, an analysis program, and a decoder. Two algorithms for encoding a string differ slightly from earlier proposals. The analysis program attempts to find an optimal set of codes for representing substrings of the file. Four new algorithms for this operation are described and compared. Various parameters in the algorithms are optimized to obtain a high degree of compression for sample texts.

Surveying instrument and method

Abstract: A tacheometer utilizes a gallium arsenide laser diode in a phase shifting distance encoder, a sinusoidal interpolator in a phase shifting shaft angle encoder, a mercury pool in a phase shifting two axis off-level encoder, a shared phase to digital decoder and a digital processor, to measure angles and distances corrected for off-level, speed of light variations, refraction and the earth's curvature.

A segmented /spl mu/-255 law PCM voice encoder utilizing NMOS technology

Abstract: A technique for pulse code modulation (PCM) encoding according to the 15-segment approximation to the /spl mu/-255 nonlinear encoding law is described. The technique makes possible the realization of a one-channel encoder together with the associated sample/hold function as a single NMOS integrated circuit. The requirements imposed on the individual components for satisfactory system performance are investigated, and it is shown that a performance can be achieved which is comparable with that required in toll quality PCM telephone transmission. Experimental results from a partially integrated prototype are presented.

DTMF Communication system

Abstract: A highly flexible and economical dual tone multiple frequency (DTMF) communication system includes a data input source such as a keyboard; a repertory dialer or electronic memory; an integratable digital encoder which includes a digital sine wave synthesizer; and a transmission unit such as a radio or a connection to a standard utility telephone system. The digital encoder provides a DTMF output signal at standard telephone frequencies in response to input data and includes a predial delay circuit which allows for dial tone delay or transmitter start up after receipt of data and before generation of an output signal, a two second delay circuit providing a two second output signal which may be utilized to prevent shut down between successive number entries and to lock out noise from a microphone or to a speaker and an automatic number insertion (ANI) circuit. When enabled, the automatic number insertion circuit automatically locks out a keyboard or other data source and transmits a 4 or 8 digit number supplied by a ROM before transmitting keyboard information. The ANI number may be used for automatic dialing, as a station identifier preceeding radio transmissions or as a code key enabling access to restricted information. Additional features provide in even further operator convenience.

Differential pulse-code modulation (PCM) with entropy coding

Abstract: As the transmission rate R gets large, differential pulse-code modulation (PCM) when followed by entropy coding forms a source encoding system which performs within 1.53 dB of Shannon's rate distortion function which bounds the performance of any encoding system with a minimum mean-square error (mmse) fidelity criterion. This is true for any ergodic signal source. Furthermore, this source encoder introduces the same amount of uncertainty as the mmse encoder. The 1.53 dB difference between this encoder and the mmse encoder is perceptually so small that it would probably not be noticed by a human user of a high quality (signal-to-noise ratio (S/N) \geq 30 dB) speech or television source encoding system.

Incremental optical encoder system for absolute position measurement

Abstract: An absolute encoding system is provided based on an incremental optical encoder which, together with a low power circuit technology and means for pulsing the light emitter(s) of the encoder (normally the largest power consuming device(s) in such a system) with a signal of low duty cycle and means for sampling the light detector outputs during the appropriate period of response to the emitted light pulses, produces an encoder system having extremely low internal power consumption allowing not only data retention but also data acquisition during periods of isolation from an external power supply by relying on its own relatively small battery-based power source.

Composite feedback predictive code communication system for a color tv signal including a carrier chrominance signal

Abstract: OF THE DISCLOSURE: For code transmission of a television signal, an interframe predictive code communication system is already known wherein interframe or previous-frame feedback is resorted to on producing prediction error signals by using samples of a previous frame as predicted samples in view of the interframe correlation of the television signal. The interframe predictive code communication system is effective for a television signal for a slowly moving object. For raising the efficiency of the code trans-mission, a composite feedback predictive code communication system is also known wherein use is made of the interframe prediction and of intraframe prediction which may be either intersample or previous-sample feedback or interline or previous-line feedback or both. A conventional composite feedback predictive code communication system is effective for a monochrome television signal because encoding is carried out with the interframe redundancy removed by the interframe prediction and with the intraframe redundancy avoided by the intraframe prediction. However, it is impossible to apply the interframe predictive and the composite feedback predictive code trans-mission directly to frequency-multiplexed color television signals. The present invention provides a composite feedback predictive code communication system directly applicable to a color television signal including a carrier chrominance signal component and compatible to monochrome television signals.Responsive to signal samples of a color television signal including a carrier chrominance signal, a predictive encoder produces quantized prediction error signals in compliance with a first transfer characteristic (1 - P1) (1 - P2), wherein minima which are substantially equal to zero are taken by the absolute value of 1 - P1 in the neighborhood of frame frequency and by the absolute value of 1 - P2 in the neighborhoods of zero frequency and subcarrier frequency.Responsive to the quantized prediction error signals, a predictive decoder produces reproduced samples in compliance with a second transfer characteristic of the inverse of the first transfer characteristic.

Security system for a solid state device

Abstract: The security system is adapted to be utilized in conjunction with a device such as an electronic calculator having solid state circuit elements formed on chips wherein the elements perform predetermined functions. The system comprises a gate formed on one of the chips for interconnecting at least two of the circuit elements in response to an enable signal. A data generator is provided and an encoding device encodes the data from the data generator as a sequence of binary signals. A reference encoder generates a preselected sequence of binary signals. A comparing device is connected to the encoding device and the reference encoder and is operable to generate and apply the enable signal to the gate when the sequence of signals from the encoding device matches the preselected sequence of signals from the reference encoder.

Time diversity data transmission apparatus

Abstract: An asynchronous, time diversity transmission apparatus including a data encoder at a transmitting location and an error-correcting data decoder at a receiving location for overcoming the effects of signal fading, impulsive noise and interference. The asynchronous data encoder encodes a single input data stream into three or more redundant, parallel data outputs having time diversity introduced by successive delays. The data outputs are frequency multiplexed and propagated over a transmission circuit. Received data is demultiplexed and input to the data decoder where it is processed to remove the time diversity. Three or more outputs from the decoder are combined to form a single, error-corrected data output.

Multiplexed data monitoring system

Abstract: A multiplexed data monitoring system for use in monitoring the status of control valves or the like in subsea petroleum well control systems, utilizes an encoder circuit located externally of the control module and composed of passive electrical components, such as inductors and capacitors, to encode switch contact closure or status information into discrete frequency data. The external encoder circuit is coupled by a pair of wires to the control module. The decoder circuitry within the subsea control module applies an alternating current signal of varying frequency to the encoder circuit and by monitoring the phase of the alternating current, the decoder circuitry can recover the data impressed by the switch contacts at the status points, which are also located externally of the control module.

Method and means for extracting variable length data from fixed length bytes

Abstract: Address codes are serially applied to parallel word-oriented memory banks, such as read-only memories, to read out successive sets of fixed length data words and control words in parallel. The data words contain variable length data, and the control words distinguish between the relevant and irrelevant bits of the data words. A stripper circuit responds to the data words and control words read out of the memory banks by extracting the variable length data from the data words under the control of the control words. One application for this system is in a run length encoder wherein the address codes are generated in response to the runs which are to be encoded, and the data words contain variable length message codes for representing those runs in encoded or compressed form.

Television signal encoder utilizing a correlation between frames

Abstract: A television signal encoder uses correlation between frames for data compression or reduction in redundancy of information to be transmitted. The coding error occurring in the interframe coding process is effectively corrected by low-bit intraframe coding with limited increase in the volume of coding information. This permits raising the significance determination threshold value without impairment of picture quality.

Adaptive predictive encoder

Abstract: In a predictive encoder, a predictive error signal is multiplied in effect by a controllable factor before quantized into information codes. A variable length coder converts the information codes into variable length codes, which are temporarily stored in a buffer memory for transmission to a receiver at a predetermined bit rate. The controllable factor is controlled by buffer occupancy of the buffer memory. Normally, the factor may be 1/2. The factor is decreased when the buffer occupancy increases towards overflow.

Floating head encoder

Abstract: An optical encoder design is disclosed which maintains a constant fixed air gap between the commutator and light sensors. The encoder head is mounted on a partially compressed hollow bellows or other spring member biasing snubber posts adjacent to the light sensors against tracks on the commutator. The height of the snubber posts above the light sensors defines the air gap.

Encoded electrical control systems for vehicles

Abstract: An encoded electrical control systems for motor vehicle employs an encoder/transmitter that provides an encoded signal and a receiver/decoder which effectuates control of an associated device only upon receipt of a signal containing the code unique to that specific receiver/decoder. For motor vehicle applications, a secure ignition system is acheived by enclosing the encoder/transmitter in a tamperproof housing associated with the ignition switch assembly. The encoded signal is transmitted when the ignition switch is closed. The receiver/decoder is contained in another tamperproof housing adjacent an ignition system component essential to engine operation, and, only upon receipt of the unique, encoded signal from the transmitter, effectuates a necessary electrical connection to this ignition system component. Operation also may be initiated by an electronic lock in place of the conventional ignition switch.

Error correction encoder and decoder

Abstract: The present invention relates to an apparatus and method for detecting and correcting burst errors of indeterminate length occurring in data entered along a magnetic tape or other storage medium. An encoder and decoder arrangement is provided wherein parity or check bytes are encoded and decoded across data blocks which are measured along and across the tracks of the storage medium and wherein the parity or check bytes are read onto separate tracks of the storage medium. The present invention provides for the continuous encoding and decoding of data because the parity bytes and data bytes are conveyed to and from the storage medium along separate tracks.

Adaptive sampling decoder-encoder apparatus and method

Abstract: A decoder-encoder with a biphase or delta-distance to binary decoding circuit adapts the data sampling interval to compensate for a non-centered signal level transition in the preceding sample interval. The location of the signal level transition in the prior sampling interval modifies the location of the subsequent sampling interval. The adaptive sampling maintains relative frequency and phase synchronization between the biphase or delta-distance source and the decoding circuit.

Remote control for communication apparatus

Abstract: A remote control arrangement for a communication system which transmits intelligence occurring within a band of frequencies f b between first and second remotely located stations is described. The remote control arrangement which is adapted to activate an element at the first station comprises an encoder located at the second station and a decoder located at the first station. The encoder provides a control signal of selectively adjustable frequency f e and period T e . The decoder includes means for detecting a control signal of corresponding frequency f e and period T e and for discriminating against signals of differing frequency and period.

System for combining analog and image signals into a standard video format

Abstract: A system for combining at least one analog signal, such as EKG signal, and an image signal, such as video signal representing a fluoroscopic view of a patient's heart or the like. The system includes a summing amplifier, which provides an input to a TV monitor and/or video recorder. The first input to the summing amplifier is provided from a TV camera arranged to view a physiological activity. A second input to the summing amplifier is provided from an encoder which receives one analog signal representing physiological data. The encoder includes an analog-to-digital (A/D) converter which receives the analog signal and feeds it to a random access memory (RAM). The A/D converter and the RAM are controlled by sync signals derived from a master camera control unit, which also provides sync signals to the TV camera.

Apparatus measuring relative velocity of movable members including means to detect velocity from the position encoder

Abstract: A transducer coupled to a motor shaft provides both position and velocity information for use in a closed loop control system. The transducer includes a disk with deposited metallic parallel conductors each conductor carrying current in a direction opposite to the adjacent conductor. Relative movement of one disk with respect to another produces a position signal in a manner well known in the art. However, multiple windings are used to provide multiple position signals displaced in space phase which are then processed by differentiation and commutation to provide a velocity signal used as a control voltage in the control loop. A reference signal is also derived by commutation from the position signal.

Selection switch memory circuit

Abstract: A selection switch memory circuit having a priority encoder for providing a code for the highest priority actuated one of a plurality of momentary contact selection switches, a memory for storing the code and a decoder for providing a select signal on one of a plurality of outputs thereof to activate a circuit corresponding to the stored code. A control includes a comparator to determine if the provided code is the same as the stored code. In one embodiment, if the provided and stored codes are the same, the memory is cleared of the stored code, and the circuit corresponding thereto is deactivated. In another embodiment, the decoder is disabled to terminate activation of the previously selected circuit if the provided and stored codes are the same. In both embodiments, if the provided and stored codes are different, the provided code is entered into the memory in lieu of the stored code. Response of the control to switch actuation is delayed to avoid deleterious effects of switch contact bounce.

Digital-to-analog converter for a communication system

Abstract: In an encoder portion, a communication system converts analog signals, into linear delta modulated (hereafter LDM) signals and LDM signals into compressed pulse code modulated (hereafter CPCM) signals while in a decoder portion, the system reconstructs the CPCM signals into LDM signals and then analog signals substantially corresponding to those originally input into the system.

Error detection and correction locator circuits

Abstract: A main memory system includes encoder and decoder circuits. The encoder circuits are connected to receive data bits and parity bits and from them generate check code bits which are stored with the data bits during a write cycle of operation. The decoder circuits are connected to receive data and check bits read out from memory during a read cycle of operation. The decoder circuits include a plurality of decoder circuits and error locator circuits. Circuits via exclusive OR circuits generate a number of syndrome bit signals. These signals are divided into first and second groups. The first group is coded to specify which one of a number of decoder circuits comprising the error locator circuits is to be enabled in the case of an error condition. The second group of signals is coded to designate the particular data bit to be corrected by the decoder circuits. Predetermined output terminals of each of the decoder circuits representative of valid single bit data error conditions are applied to a plurality of correction circuits for modification of the data signals as specified by the decoder circuits. Additionally, signals from predetermined output terminals of certain ones of the decoder circuits representative of certain single check code bit error conditions are utilized for providing the correct parity for the data signals associated therewith.

System for measuring and recording three dimensional configuration of object

Abstract: An encoder for converting a distance to an electric signal is connected with a computer to put a distance signal into the computer. Th encoder is put on a moire pattern obtained by interference between a standard grating and a deformed image of the standard grating deformed by the surface of a three dimensional object. The distance between moire fringes is put into the computer. The computer is supplied with a signal indicting whether the surface is convex or concave. The depth or height of a point on the moire pattern is calculated by the computer, and a contour of the three dimensional object is obtained. An X-Y recorder is connected with the computer to draw the contour of the object.

Annunciator communication system

Abstract: An annunciator communications system in which any one of a plurality of identical transmitting-receiving units can communicate to the rest through minimum communication links, such as power transmission lines, piping, building structures, or the like. Each unit contains a keyboard encoder controlling the transmitting section of a universal asynchronous receiver/transmitter integrated circuit to generate a modulated 200 Khz output. The receiver section of the integrated circuits in all units on the communications link receives the binary encoded data and passes it to a decoder and multiplexer that controls the input to a six-digit calculator integrated circuit that generates data output signals to a six-digit numeric display.

Binary to multistate bus driver, receiver and method

Abstract: A binary to multistate line driver and remote receiver includes a line driver comprising first and second injection logic encoder circuits. The circuits have current injectors and are connected to receive respective first and second binary signals to provide analog outputs at a signal output terminal in response to the input signals. The encoder circuits each have current injectors with substantially similar structural characteristics. The line driver further includes a reference channel circuit connected to a reference terminal to provide a reference to the encoded signals. The reference circuit has a current injector with structural characteristics substantially similar to the encoder circuit current injectors. A remote receiver has reference and signal inputs connected to the corresponding driver outputs and includes a reference level circuit for generating predetermined threshold reference levels from the reference signal, an input circuit for receiving signals and generating plural replicated outputs and a threshold detector circuit having two binary outputs and further having plural input nodes connected to the threshold signal level and the replicated outputs. The inputs at the threshold detector nodes are compared and the threshold detector circuit provides a binary output from the encoded input signal which is a replica of the binary signal inputs.

An All-MOS companded PCM voice encoder

Abstract: A per channel μ 255 CPCM encoder which can be fabricated as a single MOS chip, will be described. Experimental results from a prototype in which all analog portions were fabricated as MOS integrated circuits will be discussed.

High speed modular arithmetic apparatus having a mask generator and a priority encoder

Abstract: In a high speed arithmetic apparatus, the tally coded output of a modular mask generator addressed by a binary first operand and the tally coded input of a priority encoder are joined together by an interconnecting apparatus. The interconnecting apparatus is responsive in form to a second operand and to a selected arithmetic operation to provide at the output of the priority encoder the binary resultant of the selected operation executed upon the first and second operands. The interconnecting apparatus is disclosed in its simplest embodiment as fixed hardwired connections and in its most sophisticated embodiment as a dynamically microprogrammable full crossbar network.

Reflecting lens system

Abstract: A tacheometer utilizes a gallium arsenide laser diode in a phase shifting distance encoder, a sinusoidal interpolator in a phase shifting shaft angle encoder, a mercury pool in a phase shifting two axis off-level encoder, a shared phase to digital decoder and a digital processor, to measure angles and distances corrected for off-level, speed of light variations, refraction and the earth's curvature. A reflecting telescope is coupled to the shaft angle encoder and is incorporated in both the phase shifting distance encoder and the alignment system. The reflecting telescope has a doublet objective lens with an embedded secondary reflective surface facing a primary mangin mirror. A biconcave element of the doublet objective lens also functions as a corrector for the secondary reflective surface. A compact objective lens system is thus realized, having minimal interference between the corrector for the secondary reflective surface and the optical path through the doublet objective lens.