RU2001424C1 - Method of and device for measuring delay time in communication cable lines - Google Patents

Description

the pulse increased the noise immunity due to the trigger of the suppressed chatter coming in against it. This made it possible to conclude that the claimed inventions are interconnected by a single inventive concept.

A comparison of the claimed technical solutions with the prototype made it possible to establish compliance with their novelty criterion. In the study of other known technical solutions in the art, features that distinguish the claimed invention from the prototype were not identified and therefore they provide the claimed technical solution with significant differences to the criterion.

In FIG. 1 presents the inventive device that implements the inventive method; in FIG. 2 - practical implementation of the pulse expander; in FIG. 3 is a timing diagram of the operation of the device,

The cable communication delay delay meter comprises a comparison unit 1, a pulse expander 2, a working unipolar pulse generator 3, a measured communication line 4.

Block 1 contains the first and second inputs 5-1, 5-2 and output b connected to the first input 7-1 of the expander 2, the second input 7-2, which is connected to the bus starting pulses. The output 8 of the expander 2 is connected to the input 9 of the shaper 3, the output 10 of which is connected to the input of the measured communication line, the output of which is connected to the first input 5-1 of the comparison unit 1,

When the method is implemented, after applying a start pulse at the second input 7-2, the expander 2 forms a wide pulse, which, passing through the shaper 3, is converted into a working pulse with a duration of 1 AND the slave supplied to the test line 4. After passing through the test line, the output pulse is compared with the reference voltage and when it is higher than the reference voltage in the expander 2 form a wide pulse with a duration of + 5 g, re-form the working pulse 1 and slave and measure the period of passage of the working pulse through experienced by a communication link.

In this case, the shaper of the working pulse can be performed according to the conventional shaper on a negative front

The pulse expander 2 contains three two-input elements 11-1 ... 11-3 AND, one three-input element 12 OR. one inverter 13, two delay lines 14, 15, and one trigger 16.

The first input of the first element And is the input of the expander 2, the second input of this element is combined with the first input of the second element And and connected to the output

the first delay line, the output of the OR element is the output of the expander 2 and is connected to the second input of the second element And the input of the inverter, the output of which is connected to the input of the first delay line.

The first input of the third element And is connected to the direct output of the trigger, and the second input of this element is connected to the output of the second delay line, the input of which is connected to the inverse output of the trigger R- and

S-inputs of which through the contacts of the Start button are connected to the bus starting pulses.

In FIG. 3 shows timing diagrams of the implementation of the measurement method and

meter operation

The device operates as follows.

Operating voltage pulses are periodically supplied to the measured communication line 4, and the frequency of the working pulse passing through the tested communication line is measured by the frequency meter.

First, a trigger pulse is supplied to the second input 7-2 of the pulse expander 2, connected to the trigger pulse bus, under the influence of which the expander 2 generates a pulse of 5 g width plus output 8

momentum, where t is the time constant of the test line. This pulse is supplied to input 9 of driver 3, at the output 10 of which a working pulse is generated. whose width is adjustable depending on the varying degree of attenuation in the measured line. A working pulse is applied to the input of the measured communication line. Each output pulse from the measured communication line 4 is compared with a reference voltage

in the comparison unit 1 and when it is exceeded above the reference one, a wide pulse of 5 t width plus the duration of the working pulse is formed.

Using the proposed method

and the device provides compared with the existing following advantages:

Improving measurement accuracy by generating a working voltage pulse. formed from a wide pulse with a duration of 5 tons plus the duration of the working pulse, which allows comparing at different levels of the reference voltage.

Improving noise immunity by introducing an expander into the meter. comprising a bounce control trigger and the ability to carry out the necessary process steps.

Claims (3)

The claims METHOD FOR MEASURING DELAY TIME OF CABLE LINES AND DEVICE FOR ITS IMPLEMENTATION A method for measuring the delay time of cable communication lines, which consists in periodically supplying operating voltage pulses to the tested communication line and measuring the period of passage of the working pulse through the tested communication line, characterized in that, in order to increase accuracy and noise immunity, the working pulse is formed uni and each output pulse from the tested communication line is compared with the operating voltage and, when it is higher than the reference voltage, a pulse of 5 g duration plus the duration of the working pulse is formed ( where r is the time constant of the test line) and the working unipolar pulse is re-formed. 2. A delay meter for cable communication lines, comprising a rectangular pulse generator, including a comparison unit, to the first input of which a reference voltage source bus is connected, a frequency meter to the first output of the generator, to the second output of which a first output of the measured communication line is connected, characterized in that, in order to improve the accuracy and noise immunity, an expander is introduced into the square-wave generator 0 5 0 5 0 5 0 (56) Copyright certificate of the USSR Mg 369543, cl. G 04 F 10/06, 1971. USSR copyright certificate No. 1075230, class G 04 F 10/06. 1984. Horowitz P., Hill W. Art of circuitry, vol. 1. with 592, fig. 8.79a. pulse generator of the working pulse voltage, and the second output of the measured communication line is connected to the second input of the comparison unit, the output of which is connected to the first input of the pulse expander, the second input of which is connected to the bus starting pulses, and its output is connected to the input of the driver of the pulse the second output of which is the output of a rectangular pulse generator. 3. The meter according to claim 2, characterized in that the pulse expander contains three two-input elements, and one three-input OR element, one inverter, two delay lines and one trigger, the first input of the first element AND being the input of the pulse expander, the second the input of the first element And is connected to the first input of the second element And and with the output of the first delay line, the output of the OR element is the output of the expander and connected to the second input of the second element And and the input of the inverter, the output of which is connected to the input of the first delay line, the first The input of the third AND element is connected to the direct output of the trigger, and the second input of this element is connected to the output of the second delay line, the input of which is connected to the inverse output of the trigger, the R- and S-inputs of which are connected to the trigger pulse bus through the contacts of the Start button. Figure 1 FIG. 1