Showing papers on "Keying published in 1983"

Method of scheduling meetings

Abstract: A method of scheduling a meeting among terminal users who are provided with calendaring applications for storing and retrieving timed and dated events. Included is presentation to a meeting scheduler of a prompting screen with blanks for keying in desired times and dates, and prospective attendees. Based on keying to this screen, there is a comparison with the prospective attendees' calendars of events. The result of the comparison is an option list which is presented to the scheduler for selecting an available meeting time. Based on a selection from the option list, a meeting notification screen is built for transmitting to the attendees.

XPSK: A New Cross-Correlated Phase-Shift Keying Modulation Technique

Abstract: A new modulation technique, cross-correlated phase-shift keying ( XPSK ), is introduced. XPSK is a band-limited offset QPSK modulation technique which has an almost constant envelope. In XPSK modulators, a controlled amount of cross correlation between the in-phase ( I ) and quadrature ( Q ) channels is introduced. I and Q cross correlation reduce the envelope fluctuation Of the intersymbol-interference and jitter-free OQPSK (IJF-OQPSK) modulation scheme, introduced by Feher et al. [1], [2], from 3 dB to approximately 0 dB, thus further improving the performance of IJF-OQPSK systems in nonlinear radio systems [7], [14]. It is shown that the baseband signal of the modulator, the P_{e} = f(E_{b}/N_{0}) performance, and the spectral characteristics of nonlinearly amplified (hard-limited or saturated) radio systems of XPSK and tamed frequency modems (TFM) are practically the same. The XPSK demodulator is a conventional OQPSK demodulator, the TFM demodulator requires a somewhat more complex signal processor. For this reason, the XPSK approach may lead to significant demodulator hardware cost savings, particularly in point-to-multipoint distribution systems such as broadcast systems. Simulation results for linear and nonlinear (saturated amplifier) systems operated in an adjacent-channel interference environment (in addition to thermal noise) are presented. Measurement results performed on a 128 kbit/s rate hardware-prototype modem are also reported. Experimental eye diagram and power spectrum density measurement results are in close agreement with the computer simulation results.

Minimum-shift keyed modem implementations for high data rates

Abstract: IGITAL communications links capable of conveying data at hundreds of megabits per second (Mb/s) are becoming increasingly important in various applications. An example is the use of time division multiple access (TDMA) transmission through a satellite relay wherein several data channels are routed through single uplink and downlink paths (antenna beams). Separation of the channels from each other is accomplished through interleaving and deinterleaving in time, with possible rerouting taking place in the satellite. When carrying traffic from large metropolitan areas, the required data rates can exceed 100 Mb/s. One such implementation, currently under study by NASA,' involves data transmission at rates of up to 550 Mb/s. Such applications require the use of modulation schemes that use the available bandwidth efficiently. Furthermore, because power is at a premium on board a satellite, the utmost in power efficiency is desired of the chosen modulation scheme. This implies the use of a constant-envelope modulation scheme since amplifiers, such as traveling wavetube amplifiers, are most efficient when operated near saturation. Three popular constant-envelope modulation schemes for efficient transmission of digital data are quadriphase-shift keying (QPSK), offset (or staggered) quadriphase-shift keying (OQPSK), and minimum-shift keying (MSK). Two excellent recent articles [1,2] in IEEE Communications Magazine have discussed their general properties and attributes as well as those of other modulation schemes with constant (or nearly constant) envelopes. Other recent papers [3-61 have presented analytical results and computer

QPSK, Staggered QPSK, and MSK--A Comparative Evaluation

Abstract: Bandwidth- and power-efficient quadrature carrier modulation techniques are identified, evaluated, and compared. The modulation techniques include quadrature phase shift keying (QPSK), staggered QPSK (SQPSK), and minimum (frequency) shift keying (MSK). High quality QPSK, SQPSK, and MSK transmitters and receivers were used in the evaluation, along with a computer simulation program which modeled the hardware. Both linear and nonlinear channels were included in the comparative investigation. The agreement between simulated and measured results is shown to be excellent. In the comparison of modulation techniques, the effects of channel filtering (band limiting), nonlinearities, detection techniques, and phase equalization are addressed. The application-oriented results are intended to be an aid in selecting modulation and detection implementations, and in predicting the performance of linear and nonlinear communication systems. For systems with imperfections, data are presented for determination of passive detection filters which can outperform "matched" integrate and dump (I&D) filters.

Gas system outlet station assembly

Abstract: A gas service outlet station is disclosed having a gas-unique keying system which permits the provision of specific keying for a large number of gas services with the use of relatively few universal parts. In preferred forms, the outlet station face plate assemblies are removable from the corresponding valve bodies without destroying the required gas-unique keying between the face plate assembly, valve body and gas service box.

MSK surface acoustic wave convolver

Abstract: A surface acoustic wave (SAW) convolver is provided for use in a communication system in which a received signal incorporates a mixed pseudonoise (PN) code sequence and narrowband information signal phase-modulated thereon according to a minimum shift keying (MSK) modulation scheme The convolver includes a piezoelectric substrate capable of propagating acoustic wave signals on the top surface thereof, and a first transducer formed on the top surface for receiving the received signal and in response thereto generating acoustic surface waves along a first direction thereof A second transducer is also formed on the top surface for receiving a reference signal and in response thereto generating acoustic surface waves along a second direction thereof, the reference signal incorporating the PN code sequence phase-modulated thereon according to a bi-phase shift keying (BPSK) modulation scheme A BPSK-MSK converter integrally-formed on the substrate produces the reference signal in MSK form This structure provides a receiver having lower power consumption, fewer parts, reduced size, cost and weight and improved reliability

Digital tone generation system with slot weighting of fixed width window functions

Abstract: An electronic musical instrument wherein purely digital techniques are utilized for generating the basic waveform train and also keying the waveform train so as to have the customary keying envelope with attack, sustain and decay portions. The wavetrain is a cyclically repeated series of four-term Blackman-Harris window functions, wherein there are preferably eight such functions in each series. A plurality of individual keying envelopes are generated by a piecewise linear technique, and these envelopes are assigned respectively to the waveforms in the series so that the relative amplitudes of the waveforms can change with time over the life of the tone. This results in modulating with time the harmonic content of the tone.

Demonstration of multilevel multichannel optical frequency shift keying (FSK) with cleaved-coupled-cavity (C3) semiconductor lasers

Abstract: We report the first demonstration of multilevel multichannel (4-level, 2-channel) optical frequency shift keying (FSK) using a newly developed cleaved-coupled-cavity (C3) GaInAsP semiconductor laser operating at ~1.3 μm. This is made possible because of the very large frequency tuning rate (~10 A/mA) and frequency tuning range (~150 A) achievable with these new lasers. In addition, such a laser is also shown to operate in a highly stable single-longitudinal mode even under high-speed direct frequency modulation.

Character input device

Abstract: PURPOSE:To correct the specification error of the kind of a character only by depressing a correct character by specifying the error part by the movement of a cursor and the keying of a position specifying key even if the specification of the kind of the character is failed and keying is continued. CONSTITUTION:When an input/correction mode alteration switch 8 is turned to the correction mode and a correction signal is sent to a control part 9, the control part 9 makes a keyboard output a signal only to a character kind converting part. When the operator depresses a cursor moving key, a character kind conversion starting/ending position specifying key to indicate the division of error input, the specifying part 5 sends an address signal indicating the position of the part concerned in an input character string temporary storage part 3 to a character kind converting part 6. Subsequently the kind of a character correctly selected by a character kind selecting part 1 is inputted by keying.

Keying input device

Abstract: PURPOSE:To attain highly reliable information input without use of a mechanical contact, by shutting one of projected light of a light emitting element to one of two photodetectors and making it incident to the other from the depression of a required key. CONSTITUTION:Light emitting elements 3 and the 1st photodetector 4 are oppositely provided at both sides toward the X axis of key arrangement and the 2nd photodetector 5 is provided at one side toward the Y axis. In depressing a key 2, an incident light to the photodetector 4 is shut with the keying and luminous flux of the element 3 is irradiated to a partial reflecting plate 9 and split. A part of the light turns on the photodetector 5 and a logical value 1 is inputted to an encoder circuit 7 as an output signal and the rest split light irradiates the head of the key 2 made of a semitansparent material. Thus, output signals of the photodetectors 4, 5 are inputted to the circuit 7 to output an information signal via a control section 8.

Dynamic controller for sampling channels in an electronic organ having multiplexed keying

Abstract: The present invention is a circuit for controlling the sampling of plurality of channels in an electronic organ having multiplexed keying. The channels having information signals at a particular time period is sensed and used to address a memory. The memory has stored a plurality of sequences of digital signals for controlling the multiplexing and demultiplexing operations of the organ. Only those channels containing information signals are sampled which accordingly increases the sampling rate which increases the frequency of the harmonic component of the square wave signals that can be passed by the system and the distortion caused by aliasing of harmonics is diminished.

Differential sampling circuit for improving signal to noise ratio in an electronic organ having multiplexed keying

Abstract: The present invention is a differential sampling circuit for improving the signal to noise ratio by eliminating d.c. level distortion in square wave signals used as components for forming a stairstep or bright wave signal in an electronic organ having multiplexed keying. The multiplexed drawbar signals for even footages at both sides of a sampling resistor are demultiplexed, applied to a sample and hold circuit and applied as inputs to a differential amplifier to cancel any fluctuations of the d.c. signal component.

Manufacturing device for semiconductor integrated circuit

Abstract: PURPOSE:To effectively perform production management by a method wherein signals from a power source and main equipment such as operating signals are relayed, converted and integrated to display and record the operating condition of the equipment. CONSTITUTION:The operating signal on a switch C connected to the valve 6 of a pump 2, the rotary signal on a motor 7, the operating signal on an electrode 4, and the keying signal on a cover 3 are fed into a repeater 8 and the signals are fetched from the repeater 8 to display and record the operating condition of the equipment on an indicator 9 and a recorder 10. In this way, the operating condition is surely grasped and production management can effectively be performed.

An apparatus for waveform and envelope generation in an electronic musical instrument.

Abstract: An electronic musical instrument includes a waveform and envelope generation circuit comprising means (98) for producing a keying signal for triggering a desired musical waveform and envelope generator means responsive to the keying signal for producing an output (128) of an envelope waveform, the envelope generator means having an input connected to the keying signal and an output, and change pump means (114, 122) for incrementally transferring voltage on the input to the output under the control of a first clocking signal connected to the envelope generator means The waveform and envelope generation circuit also includes a tone generator means (168) having an input operatively connected to the envelope generator means output and responsive to the envelope waveform for producing on a further output (164) a musical waveform having an envelope following the envelope waveform, the tone generator means comprising charge pump means for repetitively and incrementally generating a complete cycle of the musical waveform under the control of the second clocking signal The instrument is arranged so that each cycle of the musical waveform has its amplitude determined by the envelope waveform Thus, in this waveform synthesis system both the waveform amplitude envelope and the waveform itself are generated using a switched capacitor technique This permits the entire circuit to be completely integrated with the pulse or DC level keying signal being connected to a control input and one or more clocking inputs for driving the switched capacitor filters

Keyboard input system

Abstract: PURPOSE:To discriminate output character type numbers by the display of the number of times of successive keying, and to speed keying, by outputting codes which differ according to the combinations of successive keying of the same shift key and keying on a character and symbol input keyboard CONSTITUTION:A keyboard 1 is provided with character input keys 10, sheet shift keys 11, and a keyboard encoder 12 A keying result encoded by the encoder 12 is inputted to a shift code detection part 20 and an output code table address generation part 40; the detecting part 20 detects a shift code and a shift frequency counter 21 counts the frequency of the generation of the shift code to display the frequency on a shift frequency display part 22 while inputting it to the generation part 40 This generation part 40 generates a different output code table address by the outputs of the encoder 12 and counter 21 to supply the address to an output code table 5 Then, uppercase alphabet, lowercase alphabet, ''katakana'' (square form of Japanese syllabary), or ''hiragana'' (cursive form of Japanese syllabary) type number codes are selected and outputted to a code output part 6 to discriminate output character type numbers, thus speeding keying operation

Video synthesizing device

Abstract: PURPOSE:To facilitate keying operation for sampling and to obtain an excellent synthesized picture by utilizing a microcomputer and setting the threshold value of the entire screen or an extracted sample point from one video signal when sampling one video signal and synthesizing the picture by inserting it into the other video signal. CONSTITUTION:A memory 5 for storing one video signal and a memory 6 for storing the other video signal are provided, and to those memories 5 and 6, a CPU with a microcomputer 1, an ROM2 stored with a program for sampling a picture from the memory 5, and a microcomputer part stored with addresses of the memory 5 are connected. Through the addess assignment of the microcomputer part, one video signal is applied from the memory 5 to the microcomputer 1 to find the mean value and threshold value for the maximum and mininum of the video signal fetched by the microcomputer 1. The level relation between the video signal in the memory 6 and the calculated threshold value and the completion of one round starting at an initially specified address are judged, thereby facilitating keying operation for sampling from the memory 5.

Display controlling system

Abstract: PURPOSE:To improve the operating efficiency of an operator, by providing a buffer separately for the instruction processing from a processor and for keying processing externally and giving the priority to the keying processing buffer. CONSTITUTION:An interface controlling section 7 of a display controller 1 makes polling operation to display devices 8-10 with keying and displays the data of an instruction processing transfer buffer 4 and a keying processing transfer buffer 3 on the devices 8-10. The number of times of the data transmitted from the buffer 4 is counted at a counter circuit 5, a specified value is set to the circuit 5, and when the data transfer of the buffer 4 is advnced to the required value, the buffer 4 stops transfer, and transmits an interruption permitting signal to an interruption gate circuit 6 via the circuit 5. When the device 8 receives the write instruction from a processor 2, the device 1 forms the transfer data in the buffer 4. In this case, when the device 9 is keyed, interruption is made to the device 2, the device 2 stops the transfer of the buffer 4, forms the keying interruption to the buffer 3 makes data transfer to the device 9.

Keyboard controlling circuit

Abstract: PURPOSE:To guarantee the content of data, by controlling a multiple keying input inhibiting mode and multiple keying input mode. CONSTITUTION:A key switch unit 1 is connected to a display controlling circuit 13 via a K/B data controlling circuit 14 and a K/B data processing circuit 18. The K/B data controlling circuit 14 controls four processing modes, i.e., multiple keying input inhibiting mode invalidating all key data, multiple keying input mode processing all key data, multiple keying mode discriminating the priority of all key data for processing, and multiple keying mode validating only the 1st key data for processing, and the character data corresponding to the read key data are processed at the K/B data processing circuit and transmitted to the display controlling circuit 13.

Arrangement for keying-in an out-of-band signal frequency

Abstract: The invention relates to an arrangement for keying an out-of-band signal frequency into the transmission path of a carrier-frequency channel converter with the aid of direct-current signals which are transmitted to the channel converter in the form of earth or non-earth and are there converted into an out-of-band signal frequency. The object of making such an arrangement monolithically integratable in a simple manner and with low losses was achieved by the fact that a capacitor (C) is charged by a switched current source (Is) via a time constant. The double-push-pull modulator, known per se and controlled by the charging and discharging voltage was modified to form a two-quadrant modulator by connecting the base terminals of three polarity-changing transistors.

Ruled line defining system

Abstract: PURPOSE:To define ruled lines with a simple operation and to simplify the constitution of the device, by correspondig the each characte position at a part of a character board to a display character location of a display mechanism and displaying the ruled lines by taking the keying position from the keying position detection mechanism as the ruled line start and end position. CONSTITUTION:A keying position on a character board 1 is detected at a keying position detection mechanism 2 and applied to a character code converting section 3 and a control section 4 from an address signal line 11. The keying position is converted into a character code at the section 3 and given to the control section 4. The control section 4 is provided with a data input mode and a ruled line defining mode to display a character corresponding to the character code on a diplay mechanism 5. In the ruled line definition mode, the operator references the screen frame 21 and a scale 22 of the board 1, keys a position in the frame 21, detects the keying position at the control section 4 to interprete the result as the start or end point of the ruled lines and to display the ruled lines on the display mechanism 5.

Circuit arrangement for the evaluation of the pilot in carrier frequency systems

Abstract: In this arrangement, the received pilot controls a group amplifier. The pilot DC is applied to a first alarm generating circuit. To achieve that a keyed pilot can be evaluated without influence from channel signals, the settling times of the pilot rectifier arrangement are shorter than the keying interval of the keyed pilot. The pilot DC is applied to a second trigger circuit which responds to the keying interval of the keyed pilot. Both alarm generation circuits are logically combined with one another by an OR gate.