Showing papers on "Encoder published in 1972"

Code element identification method and apparatus

Abstract: An improved code element identification method and apparatus wherein a code element assembly receives an interrogate signal from a code identifier assembly in an activated position of the code identifier assembly when the code element assembly is positioned in a code identifying proximity with the code identifier assembly, the code element assembly emitting a time oriented encoded responder signal in response to the received interrogate signal. The code identifier assembly receives and decodes the responder signal and generates a code valid signal in response to an identified code encoded in the received responder signal and a foreign code signal in response to an unidentified code encoded in the received responder signal. In one aspect, the present invention also contemplates an improved binary encoder module receiving a clock signal of a predetermined frequency and emitting an output signal encoded with a predetermined code.

Dual mode video encoder

Abstract: A pair of differential encoders operate in conjunction with one another to achieve improved transmission characteristics. A frame-to-frame encoder including a frame memory operates in the standard manner during stationary portions of the picture. Control circuitry monitors the magnitudes of frame differentials, and responsively thereto identifies moving portions of the picture. For those portions identified as having motion, an output code is produced by an element-to-element encoder which differentially encodes consecutive elements in the line. Whenever the element-to-element mode is utilized, the frame memory is replenished by means of the element-to-element differentials.

Encoder/decoder for code words of variable length

Abstract: An encoder/decoder is described in which a conventional feedback shift register for encoding cyclic code words is augmented by an auxiliary feedback shift register. The auxiliary register is interconnected in such a manner that it provides appropriate feedback paths for enabling error correction for a code word of any shortened length.

The spectral density of a coded digital signal

Abstract: The stochastic process appearing at the output of a digital encoder is investigated. Based upon the statistics of the code being employed, a systematic procedure is developed by means of which the average power spectral density of the process can be determined. The method is readily programmed on the digital computer, facilitating the calculation of the spectral densities for large numbers of codes. As an example of its use, the procedure is applied in the case of a specific multi-alphabet, multi-level code.

Dual mode angle encoder

Abstract: An angle encoder for selectively providing from a single rotatable code element an output indication of the angular position of the rotatable element and of angular deviation and sense with respect to a reference position. A Gray coded code element is employed and from which a Gray code is sensed to provide digital signals which are processed by associated logic circuitry operative in two modes. In one mode an output indication is provided of the angular position of the code element, while in a second mode an output indication is provided of the extent and sense of angular deviation of the code element.

Encoder readout system

Abstract: A system for reading out positional information from a linear or rotary encoder based on an extension of the pinhole imaging theory to include the effects of diffraction in the encoder. In a typical encoder, light from a radiation source is directed first through a code plate having thereon periodic markings of alternating transparent and opaque increments, then through a slit plate also having thereon periodic markings of alternating transparent and opaque increments, and then upon a detector. According to the teachings of this invention there are optimal positions for the encoder plate, the slit plate and the detector to obtain maximum readout signals from the encoder. These optimal positions are selected in theory according to two relationships which must be simultaneously satisfied, namely: Z1 nS1S2/ lambda , and Z1 (S1 - S2)Z2/ S2 where n is an integer of one or greater, lambda is the mean wavelength of the light source, S1 is the length of one clear increment-opaque increment period in the code plate, S2 is the length of one clear increment-opaque increment period in the slit plate, Z1 is the distance between the code plate periodic markings and the slit plate periodic markings, and Z2 is the distance between the detector and the periodic markings on the slit plate.

Non-linear encoder and decoder

Abstract: An encoder for serially converting pulse amplitude modulated (PAM) samples into pulse code modulated (PCM) code words and a complementary decoder for serially recovering the quantized values of the samples from the code words include respective multi-stage resistive ladder attenuators which are matched, with each attenuator having several substantially independent stages, one for each weighted time slot of the PCM code word, which are assigned respective factors from a predetermined set of factors and which are selectively switched into and out of the attenuator such that the factor assigned to each stage is multiplicatively contributed to or withheld from the overall signal attenuation level afforded by the attenuator. The encoding process involves summing the sample with a reference voltage of appropriate polarity and then progressively factoring the sum by stepping the encoder attenuator in timed synchronism with the successive weighted time slots of the code words to provide a series of trial divisors which cause the encoder to generate bits with logic levels digitally indicating those of the factors that are and are not factors of the sum voltage as the sum voltage is divided to converge on the reference voltage. The decoding process, on the other hand, involves setting the decoder attenuator to provide a multiplier comprising the multiplicative combination of the factors of the sum voltage as identified by the bits of the code word, multiplying the reference voltage by the multiplier, and then subtracting the reference voltage to obtain the quantized value corresponding to the original sample. For bipolar encoding and decoding the first time slot of each code word is reserved for a sign bit and the reference voltages for the encoder and decoder are adjusted at the outset of each cycle to reflect the polarity of the sample. Appropriate selection of the reference voltage magnitude and of the factors comprised by the encoder and decoder attenuators provides complementary non-linear encoding and decoding in accordance with a known companding function of proven effectivity for maintaining a relatively high signal-to-distortion ratio with only a relatively few time slots alotted each PCM code word.

Privacy transmission system

Abstract: A selector switching system and a number of memory devices, each capable of storing one time element of a voice transmission signal and simultaneously releasing a stored time element, which form an encoder and decoder for a transmission system, where a voice transmission signal is divided into consecutive time elements that are rearranged to form an unintelligible transmitted signal.

Rotating shaft encoder

Abstract: An encoder for producing an electrical output for each incremental rotational movement of a motor or other shaft.

Coded navigation system

Abstract: In a navigation system in which a beam of radiation is utilized for communicating information to a vehicle, such as an aircraft approaching a landing strip, there is provided a pseudo-noise generated binary code having sequentially generated bits ordered in a sequence of nonrepeating subsequences with each of these bits uniquely representing a value of a coordinate describing the position of the beam of radiation. For example, with an azimuthally scanned beam of radiation, each bit in the code represents an increment in the azimuth angle while the digits of one of the subsequences is sufficient to uniquely determine the azimuth angle. An encoder and a decoder, each similarly structured with a shift register and feedback logic, are disclosed.

Voice or analog communication system employing adaptive encoding techniques

Abstract: Voice and other analog information are transmitted from one to another of a plurality of stations in a communications system wherein, at the sending stations, an encoder samples the voice or other analog signal for sets of values of one or more characteristics, and assigned codes corresponding to the sampled sets of values are stored in sequence in a buffer. Each of the codes corresponding to the sample characteristics is assigned to respective ones of a multiplicity of discrete subperiods within each of a series of periods (P). Signal identifying receiving stations are inserted at indiscriminate rates on the transmission medium into the available subperiods having assigned meanings corresponding to the stored codes in a manner which removes the stored codes in sequence from the buffer. Each receiving station detects its own identification signal on the transmission medium and correlates the subperiods in which the identification signals are detected with their respective assigned codes. A decoder converts such correlated codes to their respective assigned sets of sample values from which it reconstructs the original voice or other analog signal. The system permits different and/or continuously varying sampling rates to be used by the stations without requiring fixed time or frequency channels. Thus, the system is generally insensitive to the kind of analog input signal waveform presented for encoding, or the type of encoding or decoding technique employed.

Digital stepping motor control system

Abstract: A control system for a stepping motor operating on the bang-bang principle in which opposing torque is exerted on the rotor of the motor as the rotor oscillates across its desired or home position. The degree of rotation of the rotor is indicated by a digital encoder, and associated circuitry or microprogramming provides a return torque on the rotor for a predetermined time, such as 120 microseconds, if the rotor oscillates across and beyond its desired position less than that amount required to produce an output pulse of the encoder. If the degree of oscillation is greater so that one but not two encoder pulses is produced, return torque is maintained until an encoder pulse is received after the rotor has reversed direction, and then no torque is applied on the rotor. If the oscillation is greater than that required to produce two encoder pulses but less than three encoder pulses, reverse torque is maintained on the rotor until the rotor returns to a rotative position corresponding to one encoder pulse. Then a torque is applied onto the rotor in the same direction as that in which the rotor initially rotated limited however to 120 microseconds duration. There is an overlap of torques between the two and one encoder pulse positions of the rotor as it returns to its home position. For oscillations of the rotor greater than those mentioned, similar applications of torque are made, so that the rotor is eventually brought to its home position.

Control system for a derrick utilizing light multiplex communication link

Abstract: A remote control system for a derrick, having an encoder network for producing a plurality of differing electrical control signal frequencies at one location on the derrick and a discriminator network at a second location on the derrick for identifying each electrical control signal frequency produced by the encoder network. An electro-optical converter communicates with the encoder to covert electrical control signal frequencies to analogous light signal frequencies. A light tube communicating with the electro-optical converter transfers the light signal frequencies from the electro-optical converter to an opticalelectro converter that communicates with the discriminator and reconverts the light signal frequencies back to their corresponding electrical control signal frequencies. The discriminator communicates with a plurality of output networks that correspond to operating members of the derrick and directs an identified control signal frequency to the output network associated with that frequency.

Radio paging system

Abstract: Direct-access paging system wherein a paging signal is originated by the person or caller who is making the page. A preassigned telephone number is called to connect the caller to the paging equipment. Additional push-buttons on the telephone are depressed according to a predetermined sequence to generate a coded input signal. The input signal is applied to decoding means which programs a paging encoder. When completely programmed, the paging encoder activates a radio transmitter which transmits the programmed paging signal. Similar paging systems may be interconnected by transmitting the coded input signal from one system to another.

Servo motor driven encoder error evaluation system

Abstract: Disclosed is a system for evaluating errors in high precision encoders. A phase-lock servo system provides accurate and constant shaft speed control of an encoder under test and integration capability is provided to average either angle or time readings obtained during a plurality of revolutions of the encoder and thereby reduce the random errors originating in the testing apparatus. Also provided is a speed perturbation generator for checking the system''s operability.

Charge parceling integrator

Abstract: A charge parceling integrator for use in delta modulation encoders and decoders has its output taken from a first, or integrating, capacitor. At the start of each cycle, the voltage across this capacitor is reduced by connecting it in parallel with a second, or decrementing, capacitor which was previously discharged. When a digital 1 is the input to the decoder or the output of the encoder, a pulse is generated and applied through a third capacitor to the parallel combination of the first and second capacitors, thereby increasing the voltage across them. The ratio of the capacitor values is chosen so that the increase in voltage across the integrating capacitor when a digital 1 occurs is twice the decrease at the beginning of each cycle.

Traffic usage encoder

Abstract: Electronic encoding of detailed traffic usage information for up to 28,800 distinct communication lines is accomplished economically by utilizing the line scanning capability of existing electromechanical Traffic Usage Recorders (TUR). A relatively small number of digital signals, typically 32, are extracted from selected points of each electromechanical TUR ''''frame'''' and are processed electronically. That processing typically includes time adjustment of 24 position signals to eliminate overlapping within each of three groups, conversion of each group to binary coded decimal form, and differential time gating of those position signals relative to six detector signals, all performed by separate circuitry for each TUR frame. The resulting time adjusted signals from all TUR frames are then supplied on a time sharing basis to common circuitry which typically converts the position signals from BCD to binary code, separately stores each signal group, and finally converts the stored signals to serial code for delivery to any desired data processing center. The system typically includes provision for increasing circuit reliability, as by checksum computation for the detector signals and production of a parity bit for each serial word as finally delivered. Further information of arbitrary type can be inserted, for example as additional bits in each word or additional words following each scan cycle.

Magnetic analog-to-digital encoder

Abstract: A magnetic shaft rotation-to-digital encoder is provided which includes magnetic sensors positioned adjacent to a high speed and a low speed magnetically coded rotatable disc, the sensors being wound with two excitation windings and an output winding, and being wired for coincident current operation in an X-Y matrix form. When X and Y signals coincide in a particular sensor core, the core is set to a logic "1," unless the sensor senses an inhibiting magnetic field on its associated disc. Each of the two rotatable discs has four binary coded magnetic tracks on its surface in the embodiment to be described. By positioning five magnetic sensors on the least significant digit track of the high speed disc, a total of eight tracks provide output signals which, when applied to appropriate logic circuitry, produce 11 output binary bits in any desired code, such as the ICAO altitude code which is in general use in conjunction with aircraft transponders.

Remote reading tilt encoder

Abstract: A pair of tilt encoders are mounted at right angles to one another. In one embodiment, each encoder comprises a pendulum connected to vary the resistance of a potentiometer as a function of the tilt angle of the pendulum. Each of the potentiometers are connected to a circuit which produces an output tilt resolution signal comprising an analog ramp function upon which is superimposed a single pulse. The time from the beginning of the ramp to the leading edge of the superimposed pulse is indicative of the tilt angle of one of the encoders while the time from the leading edge of the pulse to the end of the ramp is indicative of the tilt angle of the other encoder.

Output encoder and line driver

Abstract: A transmitter sequencer is disclosed having an encoder section and a transmission line driving section. The encoder serves to generate a biphase output code from an input level and to pass the coded message to the line driver. The line driver is normally inhibited to prevent undue loading of the transmission line, but is enabled when a message in biphase code is to be transmitted.

Digital controller for a baum folding machine

Abstract: A digital controller for controlling the operation of a folding machine enables automatic folding of a desired number of sheets responsive to entry of that number into a selector. The controller preferably includes three decade counter stages for corresponding rows of units, tens and hundreds push buttons, each stage including a decimal-to-BCD encoder for converting the selected decimal number into BCD, a buffer register for storing the output of the encoder and a digital or binary counter. The BCD representation of the selected count for each digit is loaded into the respective decade down counters. Pulses generated by a sensor and associated circuitry are used to decrease the count in the decade counters. When the content of the decade counter reaches either 0 or 1, a solenoid control valve is actuated which interrupts operation of the machine. A repeat switch, when actuated, prevents clearing of the buffer registers so that multiple groups of the same number of sheets can be folded without reentering the number into the selector.

Design of a parallel encoder/decoder for the Hamming code, using ROM

Abstract: ROM implementation of logic circuits which have a large number of inputs in generally considered unwise. However, in the design of an encoder/decoder for the Hamming code, ROM implementation is found to yield many advantages over SSI and MSI implementation. There is a one-to-one correspondence between the partition of H matrix into submatrices and the partition of the set of the inputs to the encoder into subsets of the inputs to the ROM modules. Hence, several methods of partitioning the H matrix for the Hamming code are devised. The resulting ROM implementation is shown to save package count compared with other implementations. However, at the present state of technology, there is a trade-off between speed and package count. In the applications where speed is of the utmost importance, the SSI implementation using ECL logic is the most attractive. The disadvantage of ROM in speed should diminish in the near future when semiconductor memory technology will progress to the point where the slow DTL/TTL gates in the input buffer, the address decoder, and the output buffer of ROM, can be replaced by faster gates.

Converter for gyro-compass digital display

Abstract: A gyro-compass (synchro) analog output data encoder system for open-loop control of a digital bearing angle indicator in degrees and decimal parts of degrees. Applicable, in general, to digital presentation of shaft angle changes at a remote location.

An error correcting encoder

Abstract: This relates to an error correcting PCM encoder. The encoder is of the feedback comparison type. Logic circuitry is employed to make error corrections toward the end of the encoding cycle. The encoder receives an analog input signal carrying information to be coded. The encoder produces an initial code signal representative of the information to be coded. An analog replica of the initial code signal is compared with the analog input signal. An error signal is produced if the analog input signal and the analog replica of the initial code signal differ. The initial code signal is corrected in response to the error signal to produce an error corrected output code signal.

Position indicating apparatus and digital circuitry for it

Abstract: Indicating apparatus includes an incremental shaft position encoder having a shaft whose angular position is to be indicated. A multi-phase electrical signal developed by the encoder in response to rotation of the shaft is processed by digital circuitry to provide pulses suitable for counting by an up/down counter. The counter accumulates a count that represents the net rotation of the shaft.

Encoder-decoder for pcm systems

Abstract: High accuracy at low signal amplitudes is achieved in the encoder section of an encoder-decoder for PCM signals together with low cost by using a feedback linear encoder with a digital compandor, dividing the companding scale into two ranges having an equal number of segments, providing a separate comparator for each range, and using the same set of weights for both comparators. A shift weight is provided to go from the low-level comparison to the high-level comparison, and a ratio-producing network is provided to multiply the effect of each weight by the appropriate expansion factor in the high-level comparator as compared to the low-level comparator.

Guard circuit and dwell time limiting method for three level analog encoders

Abstract: A guard circuit is combined with a three level encoder so that the encoder may be employed, for example, in a facsimile transmitter to drive a voltage controlled oscillator to thereby provide a facsimile signal suitable for transmission over a standard commercial telephone network, even should the network have one or more inband signaling frequencies within a predetermined one of the half bands of the nominal frequency range for the facsimile signal. The guard circuit limits the time the facsimile signal is permitted to dwell in the predetermined half band of its frequency range to a period which is short relative to the finite response time of the inband signaling equipment within the telephone network, thereby precluding the facsimile signal from interfering with the normal operation of the signaling equipment.

Emitter and receiver devices for remote control of mining machines

Abstract: A transmitter device is provided which includes a serial encoder which transforms input control data into a series of binary signals which are subsequently coded into a second series of binary signals. An ascending transition between levels in the second series, e.g., a transition between a binary ''''zero'''' and a binary ''''one'''', represents one of the levels of the binary signals of the first series and a descending transition represents the other of the levels. The transmitter device also includes a modulator for modulating the signals of the second series with two distinct modulating frequencies.

A Speech Encoder-Multiplexer Feasibility Study.

Abstract: : The report contains a detailed study of various voice differential PCM systems applicable for digitally encoding 3, 4, 5 and 6 voice channels into a 153.6 kilobit per second digital signal which can be used in a switched telecommunication network. Transmission of both speech and data signals over these voice channels is considered. Included in the report are: Calculations of the performance of differential PCM systems with various data signals; An analysis of the performance of differential PCM systems with speech signals; A description of a differential PCM system constructed using standard T1 technology. The research reported here consists of theoretical studies, computer simulation, subjective testing and hardware construction. (Author)

Keyboard data entry device employing reactive coupling circuits

Abstract: A keyboard device for entering data into a data processing system. Each selection key on a keyboard is coupled to a switch. Each switch is connected to an encoder through a reactive coupler which converts the switch output to pulse form. The device causes data to be delivered to the encoder in the order in which the selection keys are depressed regardless of how many keys are concurrently depressed.