Showing papers on "Keying published in 1980"

Half duplex integral vocoder modem system

Abstract: Disclosed is a system whereby in a transmit mode analog speech is sampled d converted digitally to 12 bits of accuracy and then fed into a fast Fourier transform (FFT) processor which analyzes the speech into spectral and pitch parameters. These parameters are then quantized into a data stream which acts as an input to a differential phase shift keying modulator. The modulator constructs a multi-tone modem output signal from a 25 tone stack which is converted to an analog signal which is fed into a communications channel. In the receive mode a modem input signal from the communications channel is fed through the same analog to digital converter which was used for input speech. A data stream is now provided which is coupled back into the same digital FFT processor which now operates to provide pitch spectral coefficients which are then separated and used by a synthesizer to reconstruct a speech waveform. The speech waveform is applied to a digital analog converter which is the same converter used to produce the line signal when the processor operates in the transmit mode. The FFT processor implements a single FFT algorithm which is used for both vocoder and modem processing in both the transmit and receive modes.

Improved decoding Scheme for frequency-hopped multilevel FSK system

Abstract: We have recently examined, for possible application to digital mobile radio telephony, a digital spread-spectrum technique employing multiple frequency-shift keying (MFSK) modulation with code-division-multiple access (CDMA) by frequency-hopping over a common bandwidth. The system uses the cellular approach where all mobiles within a cell communicate with a fixed base station in the cell. An analysis of base-to-mobile transmission shows that mutual interference limits the number of users which the system can accommodate at a given error rate. This paper describes a new decoding scheme to reduce mutual interference which makes use of the well-defined algebraic structure of the users' addresses. Analysis of the new decoder at high signal to noise (s/n) ratio shows it to outperform conventional decoding, allowing a 50 to 60 percent increase in the number of users who can simultaneously share the system at a given error rate. We describe a simple implementation of the decoder using shift registers.

Optimal phases of maximal length sequences for asynchronous spread-spectrum multiplexing

Abstract: Optimal phases are given for maximal length linear feedback shift-register sequences (m-sequences) of periods 31 and 63 which are to be employed as signature sequences in an asynchronous direct sequence spread-spectrum multiple access communications system. The performance measure considered is the average signal/noise ratio at the output of the correlation receiver. The data presented is applicable to various forms of direct sequence spread-spectrum modulation including binary phase-shift keying, offset quadriphase-shift keying, and minimum shift keying modulation.

Chroma keying system

Abstract: A chroma keying system which prevents the production of a chroma key signal when the primary color signals are equal is described. This system effectively prevents chroma keys on monochrome portions of color foreground camera signals. These monochrome portions are typically caused by uneven studio lighting and the resulting shadows and reflections. The system includes a comparator which compares the R, G, and B signals and generates an inhibit signal therefrom. This inhibit signal is then used to prohibit the generation of a chroma key signal.

A generalized formulation of minimum shift keying modulation

Abstract: The modulator structure consisting of a single-input two-output sequential transducer whose output sequences control the modulated signal in the manner s(t) = x(i)p(t) + y(i)q(t) is considered. Here, iT is less than or equal to t, which is less than iT + T, where T is the modulation bit duration and where x(i) and y(i) take values in /+1, -1, 0/. The behavior of a sequential transducer is characterized by means of a 'trellis'. It is shown that, provided only that the 'carriers' p(t) and q(t) have the same energy in every bit interval, the optimum demodulator for the additive white Gaussian noise channel need process the received signal over only two bit intervals in making each data bit decision. It is demonstrated that particular choices of the sequential transducer yield differential minimum shift keying and differential staggered quadriphase shift keying. Possible generalizations of this approach are discussed.

Method and apparatus for eliminating double bit errosion in a differential phase shift keying system

Abstract: A code converting circuit of simple construction composed of an exclusive OR circuit and a flip-flop circuit is provided on each of transmitting and receiving sides of a digital data transmission system according to a differential phase shift keying system, to convert two consecutive errors on adjacent bits peculiar to the differential phase shift keying system into only an error on a single bit. As a result, it is not required to employ a code having an excellent error-correcting capacity in the digital data transmission system, and thus a high transmission efficiency is attained by the use of a code which is relatively deficient in error correcting capacity.

Asynchronous interface for keying electronic musical instruments using multiplexed note selection

Abstract: An asynchronous interface includes two memories which store multiplexed keyboard information such that while one memory is writing in newly acquired key information from one musical instrument system at the clock rate of that system, the other memory is reading out previously acquired key information to a second musical instrument system at the clock rate of the second system. Periodically, based on timing signals derived from both systems, the read/write roles of the two memories are reversed. Any number of asynchronously clocked systems, each connected to an associated asynchronous interface, may be keyed by a single key multiplexing device or by the multiplexing information from another asynchronous interface.

Touch responsive envelope control for electronic musical instrument

Abstract: A touch responsive tonal envelope waveshape control sysfem is provided for an electronic musical instrument which includes cooperating tone generating and keying circuits (11) which are responsive to actuation of a key (18) for initiating the generation and keying of a corresponding tone. The system of the invention includes encoding circuits (17) responsive to the actuation of a key (18) for producing encoded signals corresponding to the intensity of player actuation of the key and an amplitude control circuit 16) responsive to these encoded intensity signals and cooperative with the tone generating and keying circuits (11) for controlling the peak amplitude of the tonal envelope waveshape in accordance with the intensity of player actuation of the key (18) for initiating that tone.

Character conversion controller of document editing device

Abstract: PURPOSE:To perform character conversion securely at a high speed and to speed up the drawing-up of a document and to improve its operability by converting a capital letter into a small letter or vice versa at every unit of character, word, line, paragraph, or page collectively. CONSTITUTION:A keyboard device 30 is provided with a character input key 30a and control input key 30b, and a key signal from the device 30 is supplied to a keyboard control circuit 31 to output a code signal, corresponding to the key signal, to a device control circuit 32. This circuit 32 exercises control corresponding to keying operation and also moves a cursor to a displayed position ocrresponding to a signal from a cursor control circuit 33. A character code signal from the circuit 32 is supplied to a buffer memory 34 and then stored at the position of a document memory 37 according to an address from an address circuit 38. Further, a discriminating circuit 36 discriminates the kind of the character code and under the control of the circuit 32, a character converting circuit 35 performs character conversion by respective units at a time, to speed up the drawing-up of a document.

Keying signal generator with input control for false output immunity

Abstract: A source of keying signals for use by keyed circuits in a television receiver comprises a keyed transistor, an input coupling circuit including a timing control circuit responsive to video sync signals for timing the operation of the keyed transistor to normally produce keying signals during blanking intervals of the television signal, and a switching network coupled to the input circuit. The switching network responds to switching signals for enabling the sync signals to be coupled to the keyed transistor via the input coupling circuit during the blanking intervals. During picture intervals of the television signal, the switching network disables the input coupling circuit to prevent the transistor from generating false keying signals in response to spurious input signals occurring during the picture intervals. In addition, the timing control circuit and transistor are isolated from the switching signal during picture intervals so that the switching signal does not upset the normally expected input timing bias of the transistor during picture intervals.

Television keying circuit

Abstract: A keying circuit for television, in the form of a special effect generator or a chroma-keying circuit. In order to generate a keying signal which does not cause flicker phenomena in an interlaced television picture when there is a great contrast in the region of a signal switch-over between two video signals in response to the keying signal, the circuit comprises a signal delay circuit and a signal combining circuit for the binary keying signal which occurs undelayed and delayed. The signal delay device has delay times of a field period minus and plus one line period or of one and two line periods, respectively. This results in a gradually changing keying signal there, where the flicker phenomenon in the interlaced television picture might occur.

Speech feedback for touch-keying

Abstract: A person keying an unfamiliar number listed in a directory, a driver keying, a mobile telephone, and a blind person making a call all face a common problem: how to key a telephone number without looking at the phone. We studied whether touch-keying that is, keying without looking would be facilitated by a talking keyset which spoke the names of the keys as they were pressed. To establish a baseline level of touch-keying performance, we also studied touch-keying with the standard TOUCH-TONE“ feedback. We found that touch-keying was much more accurate with speech than with tone feedback. Speed was not sacrificed to achieve higher accuracy; on the contrary, touch-keying was slightly but consistently faster with speech than with tone feedback. Speech feedback enabled users to catch and correct, via a CLEAR key, over 80% of their errors; tone feedback was much less effective in this regard. No training or practice was necessary to reap the benefits of speech feedback; moreover, the benefits persisted even afte...

Generalized minimum shift keying (Corresp.)

Abstract: A generalized minimum shift keying (GMSK) signal is defined, and its equivalence to a modified offset quadrature shift keying signal is shown. A simple formula for the spectrum of a GMSK signal is presented and the spectrum and out-of-band power are computed for two examples.

Keying signal generator with false output immunity

Abstract: A circuit for generating a composite keying signal comprises a gate pulse generating circuit and a voltage translating network in a television receiver also including keyed video signal processing circuits. The composite keying signal comprises a first pulse developed by the translating network during horizontal blanking intervals of the video signal, and a second pulse developed by the gate circuit during a portion of the horizontal blanking intervals and superimposed on the first pulse. An output of the gate circuit is clamped during picture intervals to a fixed voltage via a low impedance clamping path that exhibits current conduction capability greater than the output current conduction capability of the gate pulse generating circuit. The clamping action prevents improper keying of the keyed circuits in response to false keying signals such as may be generated in response to spurious signals occurring during picture intervals of the television signal.

Representation of tactile characters in scanning plane - withdrawing keying rods playing no part in sign formation and retaining below plane by EM force

Abstract: Equipment representing tactile characters in a scanning plane uses keying rods operated electro-magnetically The keying rods (2) are pressed into their normal position in the scanning plane (3) by springs (5) The keying rods playing no part in the representation of a particular tactile sign are withdrawn from the scanning plane and held below it by electro-magnetic force The springs (5) are pref mechanical and held in position against projections The electro-magnetic force is pref formed by the excitation of assigned coils (4) effecting the soft iron of the keying rods A magnetic plate can be used to hold the rods below the scanning plane

Automatic performance device of piano

Abstract: PURPOSE:To always ensure the correct reproduction of the key operation timing of the recording time by selecting the frame into which the key signal is inserted in accordance with the intensity of keying. CONSTITUTION:The output of switch circuit 2 generated through the key operation of keyboard 1 is supplied to key detection part 3a and intensity detection part 3b each. And the output of parts 3a and 3b are supplied to microprocessor 6. At microprocessor 6, the bit corresponding to the key pressed strong among the key signals is excluded from other bits in the same frame to be then inserted to the subsequent frames. And the frame to which the bit is to be inserted is decided according to the scale of the intensity signal. Thus the key to be pushed strong starts in the proper time after starting the key to be pushed softly. As a result, the actual keying is carried out simultaneously, thus ensuring the correct reproduction in the key operation timing of the recording time.

Mobile object communication unit

Abstract: PURPOSE:To obtain a mobile object communication unit by which information can be transmitted between a mobile object and a ground station in two directions simultaneously. CONSTITUTION:Information Ii1 from a master unit is coded to a digital code by digital code converter 16 and is constituted by frames together with frame synchronizing pattern code and becomes a differential phase-shift keying wave (DPSK wave) and is transmitted from coil L1 of coupler 18 to the slave unit side. Coil L1 is resonated to the f wave by capacitor C1. The f wave subjected to DPSK is induced by coil L3, and the output is inputted in parallel to modulator 34, frequency 2-multiplier 24, DPSK demodulator 25 and square wave converter 28. Frequency 2- multiplier 24 outputs a continuous-phase 2f wave to bit synchronizing circuit 26. The output of DPSK demodulator 25 is transmitted from decoder 27 to the slave unit side as information output I01. Input information Ii2 of the slave unit side is coded to a digital code by the timing control of the master unit.

Keyboard input device

Abstract: PURPOSE:To increase the key controllability by securing the sequence of the keys with no double keying in case plural number of the keys are hit virtually at one time and thus handling the key data effectively. CONSTITUTION:In case plural number of keys are hit virtually at one time, control memory 8 reads out the coordinates of the 1st key from key matrix part 12 with the control given to memorize the key coordinates temporarily in register 13. At the same time, FF10 is set, and the pulses are inhibited from pulse generator circuit 1 via AND gate 11 to stop the operation of hexadecimal counter 2. After this, part 8 transfers the information of register 13 to memory 9 for memorization. Then the FF is reset with gate 11 opened, and the counting action is restarted for counter 2. At the same time, the reading is given for the next key. Thus the sequence of the key is kept with no double keying to handle the key data effectively. As a result, the key controllability can be increased.

Keying system for an electronic musical instrument

Abstract: A keying system for an electronic musical instrument in which the absolute value of the amplitude of a musical tone signal generated with a predetermined periodicity is detected so that gating of the musical tone signal is allowed only when the amplitude of the musical tone signal is small, thereby to prevent the occurrence of click noises accompanying the keying of the musical tone signal in correspondence to depression and release of a key in a keyboard.

Agc keying signal circuit

Abstract: An automatic gain control keying signal circuit is provided for generating an automatic gain control (AGC) keying signal for a television AGC circuit. A keying signal is produced upon the normal coincidence of a sync pulse from the sync separator and a horizontal retrace pulse from the horizontal deflection system in a television receiver. The keying signal begins upon coincidence of the sync pulse and the horizontal retrace pulse and ends upon termination of the retrace pulse, thereby producing a keying signal pulse of substantially constant time duration, irrespective of the duration of the sync pulse. According to a further aspect of the invention, an "out-of-lock" signal is produced upon the occurrence of a horizontal retrace pulse which is not in coincidence with a sync pulse.

Composite keying signal generator for a television receiver

Abstract: A circuit for generating a composite keying signal includes a burst gate circuit, a clipping circuit, and a voltage divider, in a color television receiver also including means for deriving horizontal and vertical blanking signals and a horizontal sync pulse from a composite color television signal containing a color burst component. The burst gate circuit responds to the lagging edge of the horizontal sync pulse to develop a burst gate pulse encompassing the burst interval. The clipping circuit and the voltage divider serve to clip and translate both the horizontal and vertical blanking signals, which are then combined with the burst gate pulse to produce a composite keying signal. The composite keying signal comprises a first pulse component of desired magnitude as determined by the clipping and voltage divider circuits and occurring during the blanking intervals, and a second pulse component as provided from the burst gate circuit, superimposed on the first pulse and encompassing the burst interval.

Keying signal generator responsive to plural input signals

Abstract: A television receiver including a video signal sync separator and keyed signal processing circuits responsive to keying signals supplied by a keying signal generator is disclosed. The output of the sync separator is filtered to develop a bias voltage with a magnitude in accordance with the average output level of the sync separator. The keying signal generator provides periodically timed output keying signals in response to locally generated periodic horizontal flyback signals. The operation of the keying signal generator is enabled or disabled in response to the magnitude of the bias voltage derived from the sync separator output.

Merchandise selection unit

Abstract: PURPOSE:To make it possible that customers select merchandise comfortably, by providing the first and the second monitor TV receivers and a switching means and by switching the monitor TV receiver to supply the composite video signal, which has been adjusted by the first monitor TV receiver, to the second monitor TV receiver CONSTITUTION:The head part of cehcked person 1 is photographed by color TV camera 1 and is recorded on magnetic recording and reproducing device 2 Synchronizing signal generator 4 is synchronized by reproduced video signal 3 of device 2, and white-and-black TV camera 5 is synchronized by the synchronizing signal from generator 4 Camera 5 photographs the hair style model and supplies the output signal to keying pulse generating circuit 7 to generate keying pulse 8 only for the hair style part The output signal of device 2 and the output signal of camera 5 applied to synthesizing circuit 9 and are switched alternately by pulse 8 to obtain composite video signal 10 Signal 10 is projected onto monitor TV receiver 11 for operator, and the composite video signal which has been adjusted by adjusting circuit 9 to position the hair style and so on is switched by video monotor selector switch 13 and is projected onto monitor TV receiver 12 for customers

Key input ontrol systen

Abstract: PURPOSE:To reduce keying malfunction with keying operation simplified by giving a specific key both registration and arithmetic functions and by selectively fulfilling either function according to the keying operation which is done immediately before. CONSTITUTION:Through the keying operation of key input part 1, a signal is outputted from input processing part 4 corresponding to the operation key and an arithmetic process is performed by X register 5, M register 19, Y register 20, and arithmetic circuit 17. Then, a specific key such as ''pi'' key 31 is given both registration and arithmetic indication functions and either function is executed selectively according to the keying operation which is done right before. Consequently, the keying operation is simplified and keying malfunction can be reduced.

Electronic musical instrument having time multiplexed keying system

Abstract: A keying system for an electronic musical instrument incorporates time division multiplexing of the individual frequency component signals which are combined to synthesize musical notes or tones. A signal generator provides the fundamental and various harmonic frequency signals which are applied to a plurality of multiplexer circuits corresponding in number to the number of keys on the keyboard of the musical instrument. Activation of a key connects the multiplexer output signals from a corresponding one of the multiplexer circuits to a demultiplexer circuit on a common bus. Time slot signals control the multiplexers and demultiplexer to generate the desired tones corresponding to activated keys.

Information code delivery system

Abstract: PURPOSE:To make simple the keying operation, by separating the matrix group into two shifts and constituting the system that the matrix assigned to different shift is taken the same shift by delivering the shift code automatically when the matrix in other shift is keyed. CONSTITUTION:If Russian letters are used in 5 unit, for example, when the Russian matrix assigned to the numeric shift is keyed while keeping Russian letter shift, the key classifying signals open the AND gate 10, the numeric shift code is delivered from the numeric shift code generation circuit 21, FF15 is set, FF17 is reset and the status FF16 is set. Succeedingly, the information code of the characters keyed is delivered to print for the print mechanism section.

The magsat telecommunications system

Abstract: The design of the Magsat telecommunications system was based in part on using hardware from the Small Astronomy Satellite (SAS-3) wherever possible. However, the telemetry modulation control and tape recorder interface electronics were new designs. In addition, the need to accommodate the new NASA phased shift keying (PSK) uplink format, together with other considerations, led to a new command processor design, supported by existing SAS-3 power switching modules and command DC/ DC converters. Figure 1 illustrates the maj or telecommunications hardware functions and indicates the primary signal flow paths. The NASA standard transponder and associated diplexers, couplers, and antennas were shared by the command and the telemetry subsystems. From each command receiver, the bit stream from the command decoding unit went to the command processor, where the commands were decoded,

Picture signal synthesizer

Abstract: PURPOSE:To obtain a smooth synthetic picture signal by compression of the white level and edge correction of keying pulses. CONSTITUTION:The picture signal of the head of a tested person is recorded on video tape recroder VTR2 through color camera 1. The hair style model signal where the picture signal of the tested person from VTR2 and an arbitrary color are added is applied to synthesizing circuit 8 and is switched to a smooth signal by keying signal 24, thus obtaining a synthetic picture signal where the hair style model is fitted to the hair part of the tested person. Since delay of hair style model signal 21 dependent upon edge correcting circuit 7 and so on in keying signal 24 is corrected by delay circuit 9, synthesizing without time slippage for the hair style signal is performed in the synthesizing circuit.