SU1619296A1 - Device for modeling errors in fibre-optics communication line - Google Patents

Abstract

The invention relates to specialized means of computing and can be used in the experimental study and testing of the equipment of discrete information transmission systems operating on fiber-optic communication lines. The purpose of the invention is to improve the accuracy of modeling by simulating errors of only single elements. The device allows to simulate the process of asymmetrical errors in the transmitted signal sequence by introducing into the known device an additional shaper of the threshold signal and element I.

Description

The invention relates to specialized means of computing and can be used in the experimental study and testing of equipment of discrete transmission systems operating over fiber-optic communication lines.

The purpose of the invention is to improve the accuracy of modeling discrete channel errors Based on a fiber-optic communication line by simulating the errors of only / single elements of transmitted signals.

The drawing shows a structural electrical circuit of a device for modeling errors in a fiber-optic communication line.

The device contains a noise generator 1, a limiter 2, a driver of 3 error pulses, a trigger 4, element I 5, a driver of 6 threshold

signal, switch 7, element 8, element OR 9, error rate meter 10, control voltage generator 11, display unit 12, transmitter 13 and receiver 14

The device works as follows

The sequence of discrete information signals from the transmitter 13 of binary signals is fed to the input of the switch 7, which, when exposed to a sequence of impulses generated according to a given law, switches the outputs. For this to happen only at the moments when the device has single elements of the signal at the input, the shaper 6 and the K 5 element serve. The shaper 6 of the threshold signal (for example, Ymitta trigger)

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It is only when a single element exceeds the input signal of a given level. A potential appears at its output that permits the passage of error signals through the element 5. To the control input of switch 7.

The noise generator 1 produces a noise voltage, from which the limiter 2 forms a random sequence of pulses, the frequency of which depends on the level of the limit and varies depending on the level of the control voltage on the control input of the limiter 2. A random sequence of pulses with the output of limiter 2 is fed to the input of the shaper of 3 error pulses, at the output of which a sequence of short pulses is formed, grouped according to a certain law. This sequence of pulses arrives at trigger 4 with a counting input, at the output of which pulses of random duration appear, distributed according to a given law. From the output of trigger 4, a sequence of pulses of various durations at the moments of the presence of single elements of the signal through the element And 5 enters the control input of the switch 7. Switching the outputs in accordance with the control signal occurs so that the sequence of zero elements of the signal passes to the element OR 9 without distortion, and the sequence of single elements of the signal either passes to the element OR 9 without distortion, or passes through the element NOT 8, which provides an imitation of distortion single binary signals in a fiber-optic communication line.

From the output of the element OR 9, binary signals are fed to the receiver 14 of the discrete signals. At the same time, information signals from the device input are fed to one input of the error rate meter 10, to the other input of which distorted signals are fed from the output of the HE element 8

The determination of the error rate at a given analysis interval in meter 10 is the measurement of the ratio of the number of errors occurring in the transmitted binary signal to the number of transmitted symbols. In quality

The error rate meter 10 can be used a known scheme (not shown) consisting of a signal estimator, the capacity of which determines the analysis interval, and an error counter, the fault input of which is connected to the output of the signal counter and from the information outputs the error ratio values through buffer the elements used to isolate the circuits are fed to the outputs of the meter 10.

The control voltage driver 11 can be implemented using digital-to-analog converter circuits that convert the digital value of the error rate to its corresponding analog voltage value. Based on the comparison of the preset value Kosh (set manually, for example, with a potentiometer) and the control voltage of the limiter 2 obtained from the meter 10, the iterative algorithm provides a quick and accurate setting of the device to the preset parameters. The display unit 12 serves to display actual value of the error rate and provides ease of operation of the device. The element OR 9 serves to isolate the outputs of the switch 7, which is necessary for the correct operation of the device.

Claims (1)

Invention Formula A device for simulating errors in a fiber-optic communication line, comprising a noise generator, a limiter, an error pulse shaper, a trigger, a switch, a HE element, an OR element, an error rate meter, a control voltage driver, and a display of the noise generator with the information input of the limiter, the output of which is connected to the information input of the error pulse driver, the output of which is connected to the counting input of the trigger, the first output of the switch is connected to the transducer th input of the OR gate, the second output switch connected to the input of NOT circuit whose output is connected to the second input of the OR gate, whose output is the output device and the first & the counter input of the error rate meter, the information outputs of which are connected to the information inputs of the display unit, and the control voltage generator, the output of which is connected to the control input of the limiter, the information input of the switch of the error rate meter and the input of the device , characterized in that, in order to increase modeling accuracy by simulating errors of only single elements, it additionally contains a threshold signal generator and element AND, the information input of the switch is connected to the input of the threshold signal generator, the output of which is connected to the first input of element AND, the input of which is connected to the trigger output, element output And connected to the control input of the switch.