SU1598180A1 - Trunk line receiver - Google Patents

Abstract

The invention relates to communication technology. The purpose of the invention is automatic matching with the line. The receiver contains a signal receiving unit 1, a matching unit 2, a comparator 3, the first and second resistors 4 and 5, the trigger 6, the threshold element 7, the integrating chain 8, the first key 10, the generator 11, the counter 12, the second key 13. The target is reached in an account of the automatic adjustment of the resistance value of the matching unit 2 to the value of the wave resistance of the communication line. 1 il.

Description

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The invention relates to communication technology and can be used as a receiver of pulse signals transmitted over a communication line.

The aim of the invention is to automatically align with the line.

The drawing shows a structural electrical circuit of a trunk receiver.

The main receiver contains a signal receiving unit 1, a matching unit 2, a comparator 3, the first and second resistors 4 and 5, the trigger 6, the threshold element 7, the integrating chain B, the power source 9, the first key 10, the generator 11, the counter 12, the second key 13, as well as link 14 and trunk transmitter 15.

Trunk receiver works as follows.

In the initial state, an external power supply 9 of a corresponding nominal value is connected to the power terminals, providing power supply to the generator 11, threshold element 7, trigger b, counter 12, matching unit 2, comparator 3, unit 1. Line 14 connection For example, a coaxial cable with an unknown wave impedance is connected at the receiving end with a braid to the common bus and a signal conductor to the first input of the comparator 3. At the transmitting end of the link 14 is connected to the output of the main transmitter 15 of the signals. The first and second keys 10 and 13 are open.

Initially, the initial state of the counter 12 and trigger 6 is set. For this, the second key 13 is momentarily triggered and through its closed contacts the zero potential is fed to the installation inputs of the counter 12 and trigger 6. Then the key 13 returns to its initial state dah of the counter 12 are set to zero potentials (logic O), and a high potential (logical G) is set at the output of the trigger 6, allowing the operation of the counter 12.

After that, the device automatically adjusts the resistance value of matching unit 2 to equal the characteristic impedance of the communication lines 14. For this, the first switch 10 is turned on, while its first and second pairs of contacts are closed and through the first pair of contacts the potential from an external power source (not shown) is fed to the input of an integrating chain 8 formed, for example, from a resistor and a capacitor. Simultaneously, through the second pair of contacts of the key 10 is zero

the potential arrives at the permissive input of the generator 11 and closes it. The generator 11, which is a generator of rectangular pulses, begins to produce at its output a series of rectangular pulses in the form of logical O and 1, which arrive at the counting input of the counter 12. As the enable input of the counter 12 comes from the output of the trigger 6, the enable signal, the counter 12 begins to fill and at its outputs the binary code begins to grow in accordance with the number of incoming pulses. In turn, the binary code from the outputs of the counter 12 goes to the control inputs of the matching unit 2, causing Compliant increase its resistance between the two terminals.

Simultaneously with this process, when the first switch 10 is triggered at the output of the integrating chain 8, an exponential voltage boosts, which through the power bus is applied to the terminals of one resistor 4 and the matching unit 2. During this transition process, the resistance value of the matching unit 2 is adjusted to equal the impedance of the communication line 14. When this equality is fulfilled, the exponential voltage applied to the power bus must be divided at the junction point of the signal conductor of the cable 14 of the communication line and one output of the matching unit 2, i.e. to be equal to the voltage at the common point of connection of two identical resistors 4 and 5. The moment of equality of these voltages is determined using a comparator

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As the counter 12 is filled, its output code causes an increase in the resistance of matching unit 2 and at a certain moment the voltage at the first input of the comparator 3 connected to the signal core of the communication line 14 and the output of the matching unit 2 becomes equal to the voltage at the second input connected to the common point of two identical resistors 4 and 5. At the output of the comparator 3, a inhibitory signal appears, which is fed to the first installation input of the trigger 6, coaxes it so that the output of the trigger 6 produces a inhibitory signal, bl the oxidizing operation of the counter 12. The filling of the counter 12 with pulses is stopped, its output code is fixed, and accordingly the resistance is fixed: not the matching unit 2.

 Thus, when the potentials at the inputs of the comparator 3 are equal,

and the value of the control code is stored at the control inputs of matching unit 2, and its resistance between the terminals is equal to the characteristic impedance of the communication lines 14. At the end of the transition process, i.e. the charge of the capacitor of the integrating chain 8 to a constant value equal to almost the supply voltage, triggered by the threshold element 7, since it is designed for this threshold of operation. The threshold element 7 with its output signal confirms triggering of the trigger 6 and blocking the counter 12 by it. Thus, the threshold element 7 only allows the trimming circuit to operate during the voltage build-up on the power bar, since the determination of the equality of resistance of the matching unit 2 to the impedance for example

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After this automatic adjustment process, the resistance between the outputs of the matching unit 2 remains permanently and equal to the wave resistance of the link 14, thereby ensuring its coordination at the receiving end. Information signals from the output of the main transmitter 15, for example, are transmitted as a sequence of video pulses into the communication link 14, pass through it, and at the receiving end arrive at the input of the signal receiving unit 1, from which they are transmitted to other devices.

When a new communication line 14 is connected with an unknown characteristic impedance, the process described is repeated.

Formula a and 3 for brea

A trunk receiver containing a signal receiving unit, the input of which is connected to the first input of a matching unit, characterized in that, in order to ensure automatic matching with the line, the first and second keys, the integrating chain, the generator, the first and second resistors, a comparator, a threshold element are entered trigger and counter, the first input of the comparator is connected to the input of the signal receiving unit, the second input of the comparator is connected to the combined first terminals of the first and second resistors, the output of the comparator is connected to ne The first installation input of the trigger, the second installation input of which is connected to the output of the threshold element, the input of which is connected to the second input of the matching unit, the second output of the first resistor i. the first output of the integrating chain, the other output of which is connected through the first contact of the first key to the first output of the power source, the second output of which through the second contact of the first key is connected to the generator input, the output of which is connected to the counter input of the counter, the counting input of which is connected to the trigger output, the third installation input of which is combined with the installation input of the counter and through the second switch is connected to the common wire to which the second output of the second resistor is also connected, and the outputs of the counter connected to the corresponding control inputs of the matching unit.

Claims (1)

Claim A trunk receiver comprising a signal receiving unit, the input of which is connected to the first input of the matching unit, characterized in that, in order to ensure automatic matching with the line, the first and second switches are introduced, an integrating circuit, a generator, the first 10 and second resistors, a comparator, a threshold element, a trigger and a counter, while the first input of the comparator is connected to the input of the signal receiving unit, the second input of the comparator is connected to the combined first outputs of the first and second resistors, the output of the comparator is connected mounting first input flip-flop, a second adjusting input coupled to the output of the threshold element, the input of which is connected to the second input 20 of the matching unit, the second terminal of the first resistor ι. the first output of the integrating chain, the other output of which is connected to the first output of the power source through the first contact of the first key, the second output of which is connected to the input of the generator through the second contact of the first key, the output of which is connected to the counter input of the meter, the counter resolution input of which is connected to 30 output a trigger, the third installation input of which is combined with the installation input of the counter and through the second key is connected to a common wire, to which the second output of the second resistor is also connected, 35 and the outputs of the counter and connected to the corresponding control inputs of the matching unit.