RU1806443C - Device for control over transmission and reception of signals in systems with half-duplex mode of operation - Google Patents

Abstract

SUMMARY OF THE INVENTION: the device comprises keys, signal control units, NOT elements, AND elements, triggers, a communication line. 2 ill.

Description

The invention relates to the field of computer engineering and telemechanics and can be used in means for collecting and processing information.

The purpose of the invention is to reduce the number of conflicts in a half-duplex mode of operation.

In FIG. 1 shows a block diagram of a device; in FIG. 2-diagram of the relationship of the signals at the inputs of the transmitting signal of the proposed device and the state of the transmission and reception paths of the system with a half-duplex mode of operation on each side.

The device contains on each side, respectively, one input 1.4 of the transmitting signal and output 2, 3 of the receiving signal, two keys 5, 6, 7, 8, which can be performed, for example, on a relay, two blocks 9, 10, 11, 12 control of the signal, which may consist of an amplifier with a threshold device switched on at its output through the detector, the output of which

there is a logical signal, one logic element NOT 13.14, AND 15, 16, one trigger 17.18 and one control input 19, 20, communication line 21.

The device operates as follows.

The inputs and outputs of the device on each side are connected to the corresponding

the outputs and inputs of these transceivers are topics with a half-duplex mode of operation. When turned on, the transmitters continuously transmit messages, each of which has a buffer element at the beginning and a pause (absence of a signal) of a certain duration (tn) at the beginning. A signal in the form of a short-term pulse is generated at the control inputs of the proposed device, which is generated when the receiver registers the received message or if this registration is not available for a specified period. This signal also affects the transmitter00.

oh oh

Gj

Cj

ik, synchronizing the beginning of the transfer of messages.

The device operates as follows. The control signal, which is generated in the transceiver under the above conditions, acts on the trigger, which in this case includes the transmission act with key 5 (8) and includes the reception act with key 6 (7). In the event of a conflict, messages from two sides are transmitted to the communication line 21 and neither of the two receivers receives by disconnecting the reception paths with keys 6 and 7. However, due to the divergence of the frequencies / 5F of the driving transmitter generators, the ends of the messages, transmitted from different sides will diverge in time, which will lead to the appearance of a pulse at the output of one of the AND elements during a pause of the transmitted message and the presence of the signal of the received message and the translation of the trigger with which it is connected T AND gate, in a state in which one side of the transmission path is switched off and the receive path will be turned on. After switching paths on one side to the other, a similar trigger switching due to its AND element cannot occur, because in the absence of a signal from the opposite side, only one signal may be present at the inputs of the signal control blocks. With a good communication link 21 and resolution of the conflict at the start of operation of the transceivers, messages from one transceiver to another will alternate. The buffer element at the beginning of the message is intended for coordinated operation of the transmitter of one side with the receiver of the other side. The stated interconnection of the signals at the inputs of the transmitting signal and the states of the transmission and reception paths on each side is further illustrated in the diagram shown in FIG. 2.

Having a certain value t ' and entering an appropriate delay to turn on the receiving path, the proposed device can additionally perform the function of an echo suppressor.

We determine the duration tk of the conflict situation, provided that the frequency F of the master oscillator corresponds to the frequency of the carrier frequency signal. Suppose the beginning of the message signals coincide in time and the conflict situation is resolved when the ends of the messages diverge by the value of tn due to the instability F. We take into account that the relative instability of the frequency of the master oscillator

corresponds to AF / F. In this case, the value of Atk can be determined by the expression

tkfctnt-j-p)

provided that A F F. F. For specific conditions: tn, F 2 kHz, AF / F.

the value of tk corresponds to c. This means that with a T message duration of T 200-10 3 s, a conflict situation will be resolved during the transmission of the third message, and at T - 40 10 s, a conflict situation will be resolved during the transmission of the thirteenth message.

The inventive device allows half-duplex transmission of messages between transceivers on a duplex communication line with alternating data exchange between them and protection against conflict situations.

In addition, the inventive device, under certain circumstances, can fulfill the function of an echo damper.;

The inventive device operates in an automatic mode without the use of software and can be used in simple automated data collection and exchange systems for telecontrol and tele-service purposes:

35

The formula of inventions A device for controlling the transmission and reception of signals in systems with half-duplex

a clear mode of operation, containing the first key, the input of which is the input of the transmitting signal, and the output is connected to the input of the first signal monitoring unit and to the communication line, characterized in that, with the aim of reducing the number of conflicts in the conditions of half-duplex operation, on each side there is a second key, a second signal control unit, an element NOT, an AND element and a trigger, the input of the first signal control unit being connected to the input of the second key, the output of which is the output of the reception signal, the input of the first key is connected to the input the second signal control unit, the output of which through the element is NOT connected to the first input of the And element, the second input of which is connected to the output of the first signal control unit, the output of the And element is connected to the trigger input, the direct and inverse outputs of which are connected to the control inputs, respectively of the first and second keys, the trigger reset input is the control of the EXIT. M device,

A ON f / I and x t

n a fCe

/ to l g.

jtff (bf) - transmitter signal A (B)

// rn (5m) is the state of the g-packs of the horse’s ts D (Ј)

0ig. 2