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Showing papers on "Keying published in 1971"


Journal ArticleDOI
TL;DR: Computer analysis indicates the feasibility of single-stroke keying for data entry of alphabetic names using the standard touch-tone telephone pad.
Abstract: Computer analysis indicates the feasibility of single-stroke keying for data entry of alphabetic names using the standard touch-tone telephone pad. In many practical job situations little ambiguity...

52 citations


Patent
29 Sep 1971
TL;DR: In this article, a synthesis organ system with direct current keying, envelope shaping, and individual harmonic scaling is presented, which makes use of 12 musical signals representative of the notes of the top octave of the instrument and derives other note signals by frequency division.
Abstract: A synthesis organ system with direct current keying, envelope shaping and individual harmonic scaling which makes use of 12 musical signals representative of the notes of the top octave of the instrument and derives other note signals by frequency division and in which MOSFET integrated circuit technology is used in the envelope shaping, the keying, the harmonic scaling and the frequency division. The system provides for optimization of the circuit elements and internal circuits in the integrated circuit packages consistent with the number of package leads and the complexity of the external circuit so as to arrive at a minimum overall cost for the system. Alternatives are described, the choice depending largely upon the overall production quantity required, the relative cost of the packages, and to some extent upon individual preference. Other variations of the basic system are discussed. The system also has provision for all harmonic wave formation by the addition of square waves to provide pedal notes or for enlarging the keyboard resources of the instrument.

10 citations


Patent
J Darrow1
15 Sep 1971
TL;DR: In this paper, a fail-safe code keying transmitter is proposed, where a modulating signal is reshaped to remove the harmonic producing portions therefrom prior to the modulation of a carrier wave.
Abstract: This disclosure relates to a fail-safe code keying transmitter wherein a modulating signal is reshaped to remove the harmonic producing portions therefrom prior to the modulation of a carrier wave. The code keying transmitter includes an electronic switching circuit and a series resonant L-C circuit for transforming the leading edge of the square-wave input signal into one half cycle of a cosine wave and for transforming the trailing edge of the square wave input signal into another half cycle of a cosine wave and employs a modulating circuit for varying the carrier wave in accordance with the transformed cosine wave.

10 citations


Journal ArticleDOI
W. Hubbard1
TL;DR: The derivation of a rigorous (and tight) upper bound on the probability of error in a binary pulse-code modulation (PCM) twin channel optical receiver in the absence of thermal noise is sketches.
Abstract: In this concise paper we sketch the derivation of a rigorous (and tight) upper bound on the probability of error in a binary pulse-code modulation (PCM) twin channel optical receiver in the absence of thermal noise. This result is valid for any binary system, described by Poisson statistics in each of its states, in which the binary decision is based on which state has the larger count. Examples of such systems include polarization modulation, binary pulse position modulation, frequency-shift keying with separate detectors, and differentially-coherent phase-shift keying.

6 citations


Patent
27 Sep 1971
TL;DR: In this article, a keying system for interlocking the components of a beehive type project by set back force generated by firing of the projectile is described, and a pre-engraved plate is used to prevent rotation of the components and the pay load during trajectory of a projectile.
Abstract: A keying system for interlocking the components of a beehive type project by set back force generated by firing of the projectile. Tubular spacing members having smooth rims are engraved by a pre-engraved plate upon the set back force to prevent rotation of the components and the pay load during trajectory of the projectile.

6 citations


Patent
01 Apr 1971
TL;DR: In this article, an electrical musical instrument for simulating pipe organs, and having a natural ensemble effect, spatial tone-distribution effect, air turbulence effect, wind-pressure-change effect, tracker keying effect, piano voice keying, and exact differently modulated harmonic pitch registers for mutation and compound stops and chiff.
Abstract: An electrical musical instrument for simulating pipe organs, and having a natural ensemble effect, spatial tone-distribution effect, air turbulence effect, wind-pressure-change effect, tracker keying effect, piano voice keying effect, and exact differently modulated harmonic pitch registers for mutation and compound stops and chiff. Insulated gate field-effect transistors are used for switching tone and chiff frequency currents so that the change in amplitude is sigmoid during turn-on and turn-off. RC circuitry in combination with the switching insulated gate field-effect transistors permit tracker keying and piano voice keying.

5 citations


Journal ArticleDOI
W. McGee1
TL;DR: The eye function for the binary quadratic receiver is derived by examining the "eye" pattern, which shows the effective reduction in signal amplitude caused by intersymbol interference.
Abstract: The assessment of imperfect channels in data transmission usually involves noise considerations. Channel imperfections are related to system performance by determining the increase in carrier-to-noise ratio required to maintain a fixed error rate. The impairment is determined by examining the "eye" pattern, which shows the effective reduction in signal amplitude caused by intersymbol interference. This paper derives the eye function for the binary quadratic receiver. The binary instantaneous frequency discriminator, the differential phase shift receiver, and the noncoherent frequencyshift keying (FSK) receiver implemented using the difference of two envelopes are binary quadratic receivers. The eye pattern is easily obtained by computation using the eye function.

4 citations


Patent
30 Jul 1971
TL;DR: In this paper, the digital information is stored in the form of discrete audible tone bursts representative of the state of each bit of digital information, which are utilized for keying associated circuitry.
Abstract: Digital information is entered, stored on and read off of transmission channels containing audio information. The digital information is stored in the form of discrete audible tone bursts representative of the state of each bit of digital information. Subaudible tone bursts are utilized for keying associated circuitry.

3 citations


Journal ArticleDOI
TL;DR: A Kalman filtering algorithm has been applied to the problem of bit synchronization in an M -ary communication system, restricted to high SNR digital communication systems, for which acceptable error rates are obtainable without sophisticated decoding schemes.
Abstract: A Kalman filtering algorithm has been applied to the problem of bit synchronization in an M -ary communication system. No synchronizing signal is assumed present; the approach is arranged to determine timing information from the transitions occurring in a pseudorandom sequence of symbols, generated with a fixed but initially unknown bit rate. Procedural steps subdivide naturally into an acquisition phase (block data processing) and a track mode (recursion). The method is supported by sample binary frequency-shift keying (FSK) simulation results, obtained from the output of a 4-pole Butterworth digital filter fed by a random MARK/SPACE sequence plus additive Gaussian noise. Results demonstrate accurate determination of both the bit phase reference time and the bit period. The scope is restricted to high SNR digital communication systems, for which acceptable error rates are obtainable without sophisticated decoding schemes.

3 citations


Journal ArticleDOI
TL;DR: This work considers a coded digital system, where the M phases can be treated as mutually dependent random variables, and gives an appropriate minimax receiver with a guaranteed performance for all joint phase distributions.
Abstract: Wide-band multiple frequency-shift keying is perturbed by random phases in the M \geq 2 frequency slots. We consider a coded digital system, where the M phases can be treated as mutually dependent random variables. If their joint distribution is known, the optimum (maximum-likelihood) receiver is shown to be in general very complicated. We show that there are a few phase distributions and signal-to-noise-ratio extremes for which the optimum receiver and its performance can be simply described. If the joint phase distribution is not known, we give an appropriate minimax receiver with a guaranteed performance. This performance is evaluted for orthogonal coding, white Gaussian noise, and nonfading signals. It is valid for all joint phase distributions.

3 citations


Journal ArticleDOI
J. Boykin1
TL;DR: In this paper, a low pass analogy of the bandpass filter is used to estimate the effect of a filter for low indices of modulation, where each component of the modulating wave modulates the carrier independently.
Abstract: Where a frequency-shift keying (FSK)keyer generating a spectrum that is broad compared to that required for the information is used, considerable spectrum economy can often be obtained by passing the signal through a properly selected symmetrical bandpass filter. The signal can then be passed through a hard limiter which regenerates some of the sidebands filtered off, but not nearly all of them. This limiter renders the signal suitable for amplification by class C , switching type, or other high-efficiency amplifiers. For low indices of modulation, an approximation can be made of the effect of a filter by assuming that the modulation signal is filtered by the low pass analogy of the bandpass filter, and that each component of the modulating wave modulates the carrier independently.

Patent
04 Aug 1971
TL;DR: In this article, a control system for selectively operating gates distributed along a trackway in a letter sorting machine comprises a plurality of signal stores (DCA decade relays, and DA digit relays; and DCB decade relay and DB digit relay relays), and means (relays 1AC- 10AC, Figs. 3A-3D, and associated circuitry) for cyclically connecting the stores to the actuators so that at any given time, one of the stores has complete control over all the actuator, and commchanical switching mechanism (Fig.
Abstract: 1,241,608. Letter sorting. UNIVERSAL BUSINESS MACHINES Inc. 15 Oct., 1968 [27 Oct., 1967], No. 48786/68. Heading B8A. A control system for selectively operating gates distributed along a trackway in a letter sorting machine comprises a plurality of signal stores (DCA decade relays, and DA digit relays; and DCB decade relays and DB digit relays; (decade relays are on left-hand side of Figs. 3A and 3C; digit relays are along the top of Figs. 3A and 3B) adapted to store signals representative of any of the gates, input means (keys 0-9, Figs. 3A and 3C) designating the different gates, means operatively connecting input means to the stores, means for cycling the input means to each of the stores in turn so that signals designating selected gates are entered successively into alternate stores, a plurality of electromagnetic actuators (solenoids 00, 01 ... 99, Figs. 3A-3D) for operating the gates respectively, and means (relays 1AC- 10AC, Figs. 3B and 3D, and associated circuitry) for cyclically connecting the stores to the actuators so that at any given time, one of the stores has complete control over all the actuators, and means (mechanical switching mechanism (Fig. 3E) and circuitry of Figs. 3A-3D) operatively connected to the actuators to energize them for opening the gates in response to information entered in the stores. General description of circuitry.-As described, there are 100 gates having respective operating solenoids 00 to 99. There are nine keys 0-9, and in routing a letter to its destined compartment, e.g. controlled by gate 61, the first digit 6 corresponding to the tens is keyed, and then the digit 1 corresponding to the units. The first digit keyed, causes power to be applied to one of an appropriate pair of a series of so-called " decade " relay DCOA; DCOB: to DC9A, DC9B. If power is routed to the A relay of the pair, on keying the code of the next letter it will be the B relay that is energized and so on. When the second digit is keyed, power is routed to one of the appropriate pair of a series of so-called " digit " relays DOA, DOB, to D9A, D9B. If it was the A decade relay that was energized, on keying the first digit, the A digit relay will be similarly energized. This arrangement of A and B stores enables the code to be keyed corresponding to a following letter, while the first letter is proceeding along the track (not shown) between the keyboard and the designated compartment. However, to ensure that keying cannot be commenced too soon, relays KR, AB (top L.H. corner of Fig. 3A) (which control the application of power to the keys 0-9) are connected via a line 38 to two parallel power lines T1A, T1B. Line T1A includes in series the contacts 1a of the digit relays D1A-D9A and line T2A includes in series the contacts of the digit relays D1BD9B. Thus, each time the second digit of a code is keyed, the relays AB and KR are deenergized and the keys are isolated until these relays are re-energized by the operation of either of cam-operated switches C3S or C4S in lines T1A and T1B. Cam - operated switching mechanism.-The switches C3S and C4S are also shown in Fig. 3E, together with their operating cams C3 and C4, on a cam-shaft CSa which is rotated at half the speed of a cam-shaft SH. The latter is rotated in a one revolution cycle by a one-revolution clutch ORC, energized by a solenoid CL (Fig. 3E). The latter is energized by power supplied from a line S1G (shown both in Fig. 3C and Fig. 3E). Power is supplied into this line by the closure of contacts 3a of relay AB. Thus, the cycle of shafts CS and CSa commences after the keying of the second code digit. The alternate selection of the A and B stores (i.e. the A or B relays of the " decade " and " digit " relays) is effected by the operation of relays 1AC to 10AC (Figs. 3B, 3D). These are energized or deenergized by a switch C5S operated by a cam C on the shaft CSa. Thus these relays by switching on or off, cause a change between A and B stores twice every rotation of shaft CSa, and therefore once during each cycle of the clutch ORC. Power on the line SIG also initiates the operation of a vacuum pick-up (see relays Pu Pus, Fig. 3E) for transferring the letter (the code of which has just been keyed) to the trackway. Arrangement of bins.-The 100 bins 00 to 99 are arranged in primary sections P1, P2 and secondary sections S1 S2 (Fig. 2), according to their distance along the trackway from the keying operator. Each solenoid in section P1 is connected directly to a return power line T2, so that it is opened immediately the other connection to the solenoid is energized via the switches activated by the decade and digit relays as previously described. A progressive delay is applied, however, to the operating of the solenoids corresponding to gates in the P2 sections (otherwise a letter previously keyed might be received by a gate opening prematurely in respect of a following letter). Thus, solenoids in the P2 section, e.g. 09, are connected to a return line F which up to a certain point in the cycle of the shaft CS (see phase diaphragm, Fig. 5) is connected by a switch C2S to a lowpower return-line Ra. Thus at about 180 degrees of rotation of the clutch ORC, initiated at the end of keying the letter, switch C2S is operated to connect line F to line T2 and so apply full power to the solenoid 09. The latter operates in concert with the solenoid 34 since the latter controls a channel leading to bins 09 and 34 is opened by closure of a contact 09a connected with the armature of solenoid 09. All the solenoids of the bins in the S2 section have their return power connection through a line R. This is connected through a limit switch M1S to line Ra and a change-over switch M2S which is operated by the passage of a letter in the S2 section of the trackway. The letter thus operates M2S to apply full voltage to open the gate of its destined bin. M1S is operated by the letter as it enters the S1 section so as to close any bin in the S2 section, left open from a previous coding. Keying operations for special circumstances.- A key RPK controlling a relay RP (Fig. 3C), is pressed in the case of a run of letters having the same coding. This causes the letters to be cycled alternately through the A and B stores. A key CRK is pressed in order to clear the circuit when an erroneous keying operation has been carried out. A key RJK is pressed in respect of a letter carrying a code which does not lie in the range of the machine. Such a letter is then carried along the trackway to a reject bin.

01 Nov 1971
TL;DR: An analysis of information transfer requirements indicated that a vocabulary of less than 200 words could yield meaningful messages for all routine ATC transactions.
Abstract: : The project studied some methods for implementation of the man- machine interface of Digital Data Link for Air Traffic Control. An analysis of information transfer requirements indicated that a vocabulary of less than 200 words could yield meaningful messages for all routine ATC transactions. Keyboard configurations suitable for one-handed operation to yield alphanumeric outputs were studied and a ten-key character selection layout based upon sequential keying of the first two letters of the phonetic alphabet was developed.

Patent
22 Jun 1971
TL;DR: In this paper, the authors present a correlation recorder where the keying and recording functions are performed by digital circuitry and each function is synchronized to the other by a precision clock generator.
Abstract: Keying and recording functions in a correlation recorder are performed by digital circuitry. Each function is synchronized to the other by a precision clock generator. Among the functions controlled are: keying signals for initiating external events, printing of input signals representing external events, and record transport for proper positioning of the input signal on a permanent record with a precisely known time relationship to the keying signals. The time sequence of keying and recording functions is precisely adjustable over a wide range of settings.