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Showing papers on "Pulse-position modulation published in 1979"


Patent
08 Jan 1979
TL;DR: In this article, the PPM pulses in the first and second channels are translated into pulse-width modulated pulses which are then demodulated and the original data is recovered while at the same time the sampling frequency is filtered out.
Abstract: Transmitter are receiver systems are disclosed including an encoder and a decorder, respectively. The encoder samples an incoming analog video signal and operates a periodic bipolar pulse pair whose phase separation is proportional to the amplitudes of the sampled data, thus pulse position modulation (PPM). In one embodiment of the invention the coded in-phase pulses are applied to a first channel having an intermediate frequency (IF) dispersive delay line with a positive-sloped transfer function. The out-of-phase pulses are applied to a second channel having a dispersive delay line with a negative-sloped, or conjugate, transfer function. The two channels of positive and negative dispersed pulses are added together resulting in a complex IF waveform. The complex IF waveform is frequency translated to a suitable time varying DC voltage waveform for controlling a transmitter. The receiver system includes a decoder having first and second channels with respective first and second conjugate pulse compression lines or chirp filters for recovering the original bipolar coded data. The first pulse compression line, with a negative-shaped transfer function recovers the in-phase PPM pulses of the bipolar pulse pair. The second pulse compression line, having the conjungate slope, recovers the out-of-phase PPM of the bipolar pulse pair pulses. The PPM pulses in the first and second channels are translated into pulse-width modulated pulses which are then demodulated. The demodulated pulses are subtracted and the original data is recovered while at the same time the sampling frequency is filtered out.

75 citations


Journal ArticleDOI
TL;DR: A computer study to numerically evaluate the digital performance of an optical receiver with avalanche photodetectors with on-off keying, binary pulse comparison, multilevel intensity, and PPM signaling formats are considered.
Abstract: This paper reports the results of a computer study to numerically evaluate the digital performance of an optical receiver with avalanche photodetectors. Exact and approximate APD statistics were implemented and error probabilities in the range l0^{-1} to l0^{-4} were computed. Both shot-noise and receiver-noise limited conditions were examined, and on-off keying, binary pulse comparison, multilevel intensity, and PPM signaling formats are considered.

58 citations


Journal ArticleDOI
TL;DR: In this article, a hub oriented optical fiber TV distribution system is described, where a simple set-top coverter delivers pictures to a conventional TV set, and a low cost connector concept is also discussed.
Abstract: A practical hub oriented optical fiber TV distribution system is described. Pulse Width Modulation is utilized for ease in switching and a simple set-top coverter delivers pictures to a conventional TV set. A low cost connector concept is also discussed.

29 citations


Journal ArticleDOI
TL;DR: In this paper, a new optical communication system using the Pulse Interval and Width Modulated Code (PIC) was proposed, which is constructed as combinations of pulse width and interval.
Abstract: This paper proposes a new optical communication system using the Pulse Interval and Width Modulated Code. It is constructed as combinations of pulse width and interval. Then it is easy to understand that the transmission capacity of this Code is bigger than those of Pulse Width Modulation and/or Differencial Pulse Position Modulation.

24 citations


Proceedings ArticleDOI
01 Jan 1979
TL;DR: In this article, a hardware implementation of Pulse Frequency Modulation (PFM) is presented, and its operating characteristics are discussed, in the context of fiber optic tether cables between undersea vehicles and their support platforms.
Abstract: A nonlinear analog modulation scheme, Pulse Frequency Modulation (PFM), is highly amenable to fiber optic transmission, attaining performance characteristics which are attractive in the context of fiber optic tether cables between undersea vehicles and their support platforms. PFM, contrasted with traditional fiber optic modulation techniques, is shown to exhibit superior characteristics for video bandwidth, long haul transmission. A specific hardware realization which employs PFM is presented, and its operating characteristics discussed.

14 citations


Journal ArticleDOI
Akio Okazaki1
TL;DR: Pulse-Internal Modulation (PIM) is a kind of analogue pulse modulation applicable to narrow band transmission as mentioned in this paper, and it can be used for a variety of applications, such as:
Abstract: Pulse-Internal Modulation is a kind of analogue pulse modulation applicable to narrow band transmission.

12 citations


Journal ArticleDOI
J. Kasson1
TL;DR: It is the purpose of this paper to discuss the capabilities and organization of all digital PBX's currently being manufactured in the United States.
Abstract: It is the purpose of this paper to discuss the capabilities and organization of all digital PBX's currently being manufactured in the United States. A digital PBX is one which encodes incoming signals into representations where the presence, or absense, of pulses, or levels, defines the signal; such a system switches signals by routing, multiplexing, or storing these pulses or levels. Pulse amplitude and pulse width modulation systems are thus excluded from this discussion.

8 citations


Proceedings ArticleDOI
27 Mar 1979
TL;DR: It is proved that this modulation scheme does not only give the same amount of the improvement effect on the digital signaling on an overlapped area, but also makes the allowable carrier frequency drift several times lager than that of the carrier frequency offset strategy.
Abstract: Many mobile radio communication systems require digital siganling simultaneously from multiple transmitters from the viewpoints of efficient frequency utilization and simplified receiver construction. This paper describes a new modulation scheme in order to realize a simulcast digital transmission. In this method modulation signal is made by superimposing a sinusoidal wave on an ordinary rectangular digital wave. When Manchester-coded type signal is used, the frequency of the sinusoidal wave is twice as much as that of the original bit-rate and the relative phase difference between the two waves is different at each base station. In order to clarify the feasibility of this technique, experimental simulation tests are performed on 900-MHz band in two transmitter construction. It is proved that this modulation scheme does not only give the same amount of the improvement effect on the digital signaling on an overlapped area, but also makes the allowable carrier frequency drift several times lager than that of the carrier frequency offset strategy.

8 citations


Proceedings Article
01 Jan 1979

7 citations


Patent
05 Jul 1979
TL;DR: In this paper, a method for demodulating a pulse width modulation encoded analog signal was proposed, in which the analog signal is retrieved from individual pulsewidth modulation cycles, only if missing pulse detectors confirm that the pulse-width modulation cycle was valid.
Abstract: A method of demodulating a pulse width modulation encoded analog signal wherein the analog signal is retrieved from individual pulse width modulation cycles. A method of sampling and outputing the retrieved analog signal only if missing pulse detectors confirm that the pulse width modulation cycle was valid. And a method generating a second but inverted play-back signal permitting use of two identical pulse width modulation transition descriminators-detectors.

6 citations


Journal ArticleDOI
Luciano Bosotti1, Giancarlo Pirani1
TL;DR: A combined pulse amplitude modulation (PAM) and pulse position modulation ( PPM) technique is proposed and investigated as a feasible solution of the problem of line encoding in optical fibre communication systems.
Abstract: A combined pulse amplitude modulation (PAM) and pulse position modulation (PPM) technique is proposed and investigated as a feasible solution of the problem of line encoding in optical fibre communication systems The basic idea is that of exploiting PAM and PPM jointly, to give rise to three different waveforms in one signalling period, without resorting to more than two signal levels Some evaluations of the behaviour of this signalling format are reported in terms of coding efficiency, spectral density, timing information, and error probability Alternative receiving schemes are also devised to improve system performance






Journal ArticleDOI
TL;DR: A versatile full-duplex baseband modem has been built which interfaces with tactical VHF radios and operates from 75 bits/s to 16 kbits/s.
Abstract: The evaluation of FM radios designed primarily for analog voice traffic, but used for data transmission, requires operation over a wide range of data rates and modulation formats. A versatile full-duplex baseband modem has been built which interfaces with tactical VHF radios and operates from 75 bits/s to 16 kbits/s. The choice of modulation formats, modem implementation, and some performance results are presented in this paper.