SU1425837A1 - Method of transmitting digital information video pulses - Google Patents

Description

(21) 4213658 / 24-24

(22) 03/20/87

(46) 09/23/88. Bul N 35

(71) Special Design and Technology Bureau with a pilot production at the Belarusian State University. IN AND. Lenin

(72) N.P. Popkov and V.L. Kirillov

(53) 621.398 (088 “8)

(56) USSR Author's Certificate No. 1164892, class, H 03 M 13/00, 1985.

Shvartsman V.O., Emelov G.A. Theories of discrete information transfer. M .: St. Hb, 1979, p. 138.

(54) METHOD FOR TRANSMITTING VIDEO IMPULSES OF DIGITAL INFORMATION

(57) The invention relates to a pulse technique and can be used to transmit digital information over electrical and optical communication lines. The purpose of the invention is to increase

the reliability of transmission due to the weakening of the lateral components in the energy spectrum. The device contains an information source 1, a shaper 2, a code generator, a clock frequency generator 3, an adder 4, a delay element 5, an output matching block 6, a communication line 7 and an input matching block B. The essence of the method is to form a bi-pulse phase-shifted signal from the original binary signal, shifting each pulse by one cycle and subtracting the corresponding pulses from the original bi-pulse sequence; transmitting the generated signal over the communication line. As a result of the transformations, the spectrum of the signal changes, and its transmission over the communication line, in which the upper frequencies of the spectrum are attenuated, is performed with higher reliability. 2 Il.

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11425837

The invention relates to a pulse technique and can be used to transmit digital information on electrical and optical communication lines.

The purpose of the invention is to increase the reliability of transmission over the communication line with the attenuation of high frequencies due to the weakening of the side components in the energy spectrum. FIG. 1 shows a functional diagram of a device implementing the proposed method; Fig. 2 shows timing patterns of signal formation. The device (FIG. 1) contains the source 1 of digital information, the code driver 2 ,. 3 clock frequency generator, adder 4, delay element 5, output matching unit 6,

link 7, input matching unit 8.

The device works as follows.

Digital information source 1 generates a binary digital signal (Fig. 2a) according to the clock frequency generator 3 clock (Fig. 6) 5 which determines the transmission rate of digital video-pulses and is also a carrier frequency generator for bio-pulse coding in code generator 2. ,

Code driver 2 generates, for example, bi-pulse relative (figv) or absolute (fig.2z) signal. The generated signal is converted by linear-phase pulsed filtering into a signal with new properties (FIG. 2d), in which it is stored. the positive properties of a linear bio-pulse signal (presence of sync information), the absence of a constant component, etc.), as well as low-frequency components in the energy spectrum, due to which transient and intersymbol interference do not affect the distortion of information components pulse sequence at 30

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с к с l and l Ж Т х п м с х and в

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putting them in a line with integrating properties. Pulsed filtering of a bi-pulse signal is carried out by shifting it within a single clock cycle using delay element 5 and subtracting the shifted signal (Fig. 2d) and not shifted (Fig. 2b) by means of the circuit of adder 4 with inverse and direct inputs.

The generated signal (figd) agree on the parameters of a particular line using the output matching unit 6 and sent to the line. A fiber optic line, a coaxial or other cable can be used as a link 7 (4 links. For economic reasons, the pulse transmission frequency is set to be the highest when the output of link 7 still has features to recognize video information pulses background noise, distinctive features for recognizing video pulses include a sign of a clock frequency (synchronization), which distinguishes each bit of information from each other, and a sign that distinguishes between bits of information on the information vidg (for two O or O

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1), In long lines with limiting transmission frequencies, the integrating properties of cables and the load of 5 photodetectors, t, e. in general, a linear path contributes to the distinguishing features for recognizing video pulses without intersymbol influence, if the transmitted pulses are formed according to the described techniques (fig.2d, d, l, o, where the integrating effect on the signals is shown by a dashed line) zi in the input matching unit 8 signal amplify by. the attenuation pattern in the linear path and, if necessary, level the unevenness of the phase-frequency characteristic of the communication channel by the phase link. The output of the input matching unit 8 receives a signal with the necessary features (FIG. 2e) 5 by which the original binary signal is restored (FIG. 2a). In code generator 2, bi-pulses of different duration can be double (Fig. 2c) and single (FIG. 2i) according to the law of alternation of polarity in each bi-pulse, as well as encoding a single pulse of different duration according to the law of alternation of polarity of each pulse (Fig. 2m). Comparison of the calculated energy spectra of such signals is given in additional materials. The use of one or another method of coding and in the case of impulse filtering is due to the used communication lines in order to optimally match the spectrum

signal with the characteristics of the used communication channel. In this case, the condition for coding digital signals with subsequent pulse linear-phase filtering is the formation of characteristics in the signal, due to which unambiguous distinctive features should be distinguished when recognizing video pulses of the original digital information (fig. 2d, d, l, o).

The method of transmitting video pulses of digital information eliminates the effect of intersymbol interference, reduces transient interference from the transmitted pulse sequence to neighboring signals located in the lower frequency region of the communication channel, which ultimately increases the efficiency by 1.5–2 times. - -giveness of cable lines.

Claims (1)

The invention The method of transmitting digital video pulses of information is that each pulse of an initial sequence of digital binary video pulses of duration T is transformed into two biopolar pulses of duration T / 2 according to the law of phase modulation and is transmitted to the communication line, characterized in that, in order to increase the reliability of transmission over the communication line with the attenuation of high frequencies due to the attenuation of the lateral components in the energy spectrum, each biopolar pulse before transmission to the communication line They jump in time for the T / 2 interval, followed by amplitude subtraction from the corresponding initial biopolar pulse. f / o t / S s d five g d / f I and to   g -LJLJ || w .. "J m n o I o I rHj