RU2315425C2 - Device for encoding, receiving and transmitting digital information through electric networks - Google Patents

Abstract

FIELD: transmission of digital information through electric networks.

SUBSTANCE: in accordance to the invention, transmitter is fitted with two amplifiers, outputs of which are connected to output keys, and inputs are connected to signal transformer outputs, detector is fitted with two diodes, an adder, one inverting and one non-inverting amplifier, inputs of which are connected through diodes to receiving winding of transformer of matching and bypassing device, and outputs are connected to inputs of adder, where output of adder is connected to input of comparator, and receiver is fitted with block for checking trustworthiness of received information, input of which is connected to comparator output, additional output is connected to additional input of signal transformer, and another output is information output of device as a whole.

EFFECT: increased interference resistance and increased trustworthiness of received digital information.

3 cl, 1 dwg

Description

The invention relates to telecommunications and electrical engineering, in particular to a system for transmitting and receiving information, in particular to systems for transmitting and receiving information over power electric networks.

A device is known for broadband transmission and reception of information on power grids (RU 2216853 C2), comprising a transmitter control unit, a modulator, a channel encoder and a chaotic signal generator on a transmitting side, a filter, an amplifier, an integrator, a receiver control unit and a receiver decision unit, on a receiving side, as well as a filter for connecting to the power network of the transmitting and receiving sides.

It is known that a device for transmitting and receiving information (RU 2232465 C2) is intended for transmitting and receiving information mainly along power lines of an electric network, on the transmitting side of which there is an information preprocessing unit, a transmitter, a sinusoidal voltage generator, a transmission mode control unit, a first synchronization unit, a unit power settings, a voltage converter and a unit for storing voltage and generating delta pulses, and on the receiving side, the device contains a matching unit, receiving IR block sensitivity correction information processing unit, the reception mode control unit and the second sync block.

However, in these devices the transmission speed of information over the communication line is low, which is determined by the method of quantization of transmission chosen in them.

Known devices, in particular a device for encoding, receiving and transmitting digital information via a two-wire communication line (RU 96112687/09).

This device includes transmitting and receiving parts.

The transmitting part includes a logical to differential signal converter, the outputs of which are connected to the inputs of the encoder, the direct output of the logical signal to differential converter being connected through the first and second resistors to the control input of the first key, the first capacitor connected between the direct output of the logical signal to differential converter and the control input of the first key, the inverse output of the logical to differential converter is connected through a third resistor and into the second capacitor with the control input of the second key, the outputs of the first and second keys are combined into a common point with the minus of the power source, the input of the first key is connected to the beginning of the first primary winding of the matching and decoupling device, the output of the power source is connected to the beginning and end of the second and first primary windings matching and isolation devices, the direct output of the logical-to-differential converter is connected through the fourth resistor connected in series, the first diode with the input of the second switch cha, the inverse output of the logic signal to differential converter is connected through a fifth resistor connected in series, a second diode with a control input of the first key, a third capacitor connected between the minus of the power source and the anode of the first diode, a fourth capacitor connected between the minus of the power source and the anode of the second diode.

The receiving part includes a receiver - decoder, consisting of a comparator, the direct output of which is connected through a resistor to the beginning of the first output winding of the matching and isolation device, the inverse input of the comparator is connected through the resistor to the end of the first output winding of the matching and isolation device, between direct input and direct the resistor is turned on by the output of the comparator, a resistor is turned on between the inverse input and the inverted output of the comparator, the blocking device consists of a diode connected by the anode to the anode of the first diode, and cat the input to the third key and the common point of the first and second resistors, the input of the third key is connected to the minus of the power source, and the control input of the key is connected to the output of the control device.

Judging by the description, this device can be used to transmit digital information over a two-wire line intended only for information transfer, i.e. made or used only for these purposes, and cannot be used to transmit information over the power electric network, including cable lines under high voltage.

This device does not check the received information for reliability, which reduces the noise immunity of the device, and as a result, can lead to the reception of erroneous information, which is especially critical for a digital stream.

The objective of the invention is to increase the noise immunity and reliability of the received digital information, subject to the transmission of information over electrical networks.

The problem is solved as follows: a device for encoding the reception and transmission of digital information over electrical networks, containing a signal converter equipped with at least two outputs, the input of which is an information input of the device, a transmitter equipped with two output keys, a receiver containing a detector and a comparator , a matching and isolation device including a transformer with four windings, the output winding being connected to the electric network, the receiving winding being connected to the input at the receiver, and the other two to the output of the transmitter, and the transmitter is additionally equipped with two amplifiers, the outputs of which are connected to the output keys, and the inputs are connected to the outputs of the signal converter. The detector is equipped with two diodes, an adder, inverting and non-inverting amplifiers, the inputs of which are connected through diodes to the receiving winding of the transformer of the matching and decoupling device, and the outputs are connected to the inputs of the adder, and the output of the adder is connected to the input of the comparator, and the receiver is equipped with a validation unit for the received information the input of which is connected to the output of the comparator, the additional output is connected to the additional input of the signal converter, and the other output is an information output devices in general. The receiver is also additionally equipped with a digital-to-analog converter, and the inputs of the digital-to-analog converter are connected to additional outputs of adjusting the level of operation of the comparator of the unit for checking the accuracy of the information received, and the output is connected to the control input of the comparator. The output winding of the matching and isolation device is connected to the electric network through a high-voltage isolation capacitor.

The proposed device for encoding, receiving and transmitting digital information over electrical networks is illustrated in the drawing, which shows a block diagram of the device.

1 - signal converter

2 - amplifier

3 - output key

4 - damping diode

5 - resistor

6 - the first winding of the transformer 7

7 - transformer

8 - amplifier

9 - output key

10 - damping diode

11 - resistor

12 - the second winding of the transformer 7

13 - diode

14 - receiving winding of the transformer 7

15 - inverting amplifier

16 - diode

17 - non-inverting amplifier

18 - adder

19 - comparator

20 - block verification of the accuracy of the information received

21 - digital-to-analog converter

22 - transformer output winding - 7

23 - high voltage isolation capacitor

The transmitting part of the device consists of a signal converter - 1, one output of which is connected through an amplifier - 2 with an output key - 3, to the output of which a cathode of a damping diode - 4 is connected and connected through a resistor - 5 to the first winding - 6 of the transformer - 7, and the second the output of the signal converter - 1 is connected through an amplifier - 8 to an output key - 9, to the output of which a cathode of a damping diode - 10 is connected and connected through a resistor - 11 to the second winding - 12 of the transformer - 7. The second outputs of the keys 3 and 9, as well as the anodes damping diodes 4 and 10 with dineny with less power, and the first end and the beginning of the second primary winding (6 and 12) of the transformer - 7 are connected to a plus power source.

The receiving part of the device includes a detector, which consists of a diode - 13, the cathode of which is connected to the beginning of the receiving winding - 14 of the transformer - 7, and the anode - to the input of the inverting amplifier - 15 and the diode - 16, the anode of which is connected to the beginning of the receiving winding - 14 of the transformer - 7, and the cathode - with the input of a non-inverting amplifier - 17. The end of the receiving winding is connected to the minus of the power source. The output of the inverting amplifier - 15 is connected to one of the inputs of the adder - 18, and the output of the non-inverting amplifier - 17 is connected to the other input of the adder - 18. The output of the adder - 18 is connected to the input of the comparator - 19. The output of the comparator - 19 is connected to the input of the validation unit received information - 20, which is connected to a digital-to-analog converter - 21, the output of which is connected to the control input of the comparator - 19. The output of the validation block of the received information - 20 is the information output of the device.

The additional input of the signal converter - 1 is connected to the additional output of the unit for checking the reliability of the received information - 20.

The output part of the device consists of the output winding - 22 of the transformer - 7, connected through a high-voltage isolation capacitor - 23 device matching and isolation with the electric network.

The transmitting part of the device operates as follows. The transmitted digital signal is fed to the signal converter - 1.

Since the signal converter - 1 has internal memory registers and an arithmetic-logic device, it is programmed so that upon receipt of serial digital information it splits it into separate fragments equal to the duration T, then calculates the sum of unit bits of the current fragment of digital information to obtain the checksum value . Next, the signal converter - 1 forms a frame of the transmitted information in the following sequence: a start bit, which is a single bit of double duration, then a transmitted fragment of digital information and a checksum. The duration of the information bits in the frame is reduced so that the time of the resulting frame is not more than T, as a result of which the entire resulting frame of transmitted information is compressed in time.

Since the signal converter - 1 cannot generate a bipolar signal, the output signal is logically divided into two signals of positive polarity. When the logical “1” of this frame is transmitted, a modulated signal is generated at the output of the signal converter - 1. Moreover, at the first output of signal converter 1, periodic pulses are generated, the repetition rate of which is equal to the selected carrier frequency and duty cycle equal to one, and at the second output of signal converter 1, the same pulses are generated, but with a delay of half the period of the carrier frequency. When transmitting a logical “0” at the output of the signal converter, 1 signal is absent.

The signals are transmitted, respectively, to the amplifier - 2 and amplifier - 8 of the transmitter, where they are amplified by current and voltage to the required level for controlling the output keys - 3 and 9 of the transmitter. The output keys of the transmitter - 3 and 9 are used to build up the transformer - 7 device matching and isolation. In order for the transmitter keys not to fail under the influence of the EMF voltage of the transformer self-induction - 7 matching and isolation devices, damping diodes - 4 and 10 are connected to their output. Moreover, their anodes and second outputs of the output keys - 3 and 6 of the transmitter are connected to the minus of the source nutrition. The end of the first and the beginning of the second transformer windings - 7 matching and isolation devices are connected to the plus of the power source. Resistors - 5 and 11 of the transmitter are used to limit the maximum current of the output keys - 3 and 6 of the transmitter. On the output winding - 22 transformers - 7 matching and isolation devices during the opening of the first key - 3 transmitters, a positive modulated signal half-wave is formed, and during the opening of the second key - 9 transmitters - negative. From the output winding - 22 of the transformer - 7 devices matching and decoupling the signal through a high voltage isolation capacitor - 23 enters the electrical network, which is a communication line.

The receiving part of the device operates as follows. The received signal from the electric network through a high-voltage isolation capacitor - 23 is transmitted to the output winding - 22 of the transformer - 7 matching and isolation devices. Due to the transformer connection between the transformer windings - 7 on the receiving winding - 14 of the transformer - 7 of the matching and decoupling device, there will also be a received signal that goes to diodes - 13 and 16. The diode - 13 is connected by a cathode to the receiving winding - 14 of the transformer - 7 of the matching device and isolation, so only a negative polarity signal passes through it, which is amplified and inverted by the inverting amplifier - 15. After passing the inverting amplifier - 15, the signal of negative polarity becomes It is amplified by voltage with a signal of positive polarity. The diode - 16 of the non-inverting amplifier is connected by the anode to the receiving winding of the transformer - 7 and transmits only pulses of positive polarity, which are amplified by the non-inverting amplifier - 17. Thus, the inputs of the adder-18 receive pulses of positive polarity from the inverting - 15 and non-inverting - 17 amplifiers. In the adder - 18, the signals are summed according to the absolute value, therefore, a detected signal is generated at its output. This scheme of signal detection by initial separation of the signal, then amplification, and then summing provides a high definition signal detection, despite the fact that the pulse width is not constant in a digital signal. This signal goes to comparator - 19, at the output of which it becomes digital and has only two states “0” or “1”, where “0” corresponds to the absence of voltage, and “1” to high voltage. This signal is input to the check unit for the reliability of the information received - 20 for further processing. Validated signal from the output of the validation block received information - 20 is the output signal of the receiving part of the device.

The device provides automatic adjustment of the response level of the comparator - 19. For the correct operation of this automatic adjustment in the receiving part of the device, the transmitted information should consist not only of the transmitted information, but also of the service. To do this, the signal converter - 1, all digital information on the transmitting side is divided into frames with alternation inside it as follows: start bit - a fragment of the transmitted information - the checksum. The checksum is the number obtained by summing the unit bits in the transmitted information within the frame. At the receiving side, the calculated bit sum of the received information inside the frame is compared with the received checksum.

Automatic adjustment of the response level of the comparator - 19 includes a validation unit for the received information - 20 and a digital-to-analog converter - 21. The comparator - 19, used in the device, has one analog input for signal comparison, an analog control input and one digital output. Comparator - 19 works as follows: if the voltage level at the analogue input of the comparator is lower than at the control input, then its digital output will have a voltage corresponding to the logical “0”, and if the voltage at the analogue input of the comparator exceeds the voltage at the control input, then the output of the comparator voltage will correspond to a logical unit. The digital signal from the output of the comparator - 19 is fed to the verification unit for the reliability of the received information - 20. The verification unit for the reliability of the received information - 20 generates a digital code for setting the comparator response level - 19. The digital code is generated as follows: on m additional logic outputs for level adjustment comparator operation, an m-bit binary number is formed (in this case, a four-bit binary number, because the number of additional logic outputs is 4). The code goes to the inputs of the digital-to-analog converter - 21. The digital-to-analog converter - 21 generates an analog voltage from the digital code, which is proportional to the value of the code. The voltage from the output of the digital-to-analog converter - 21 is supplied to the control input of the comparator - 19. The validation block of the received information - 20 constantly compares the number of unit bits of the transmitted information with the checksum of this frame inside each received frame. If the calculated amount does not match the accepted checksum, then the validation block of the received information - 20 changes the code at the input of the digital-analog converter - 21 and gives an error command to the signal converter - 1 through an additional output, which is connected to the additional input of the signal converter - 1. Change the code at the input of the digital-to-analog converter - 21 occurs by adding one to the current m-bit binary number. The signal converter - 1, after receiving the error command, sends the error command to the communication line with the transmitter to another device that transmitted digital information to retransmit the last frame of information. This process is repeated until the sum of the unit bits of the transmitted information coincides with the checksum in the new received frame.

The signal converter - 1 splits the transmitted digital information into frames and adds a checksum of bits in each frame, and the validation block of the received information - 20 constantly checks the received information for validity by checking the calculated sum of bits of the transmitted information in the frame with the checksum and with a positive check provides information to the output of the device. If the received information is checked negatively, the received device transmits to the transmitting device a retry command for transmitting the last frame of digital information. Thus, high noise immunity and reliability of the received information is ensured.

Since the output winding - 22 of the transformer - 7 matching and decoupling devices is connected to the communication line through a high voltage capacitor - 23 matching and decoupling devices, this device can be used to transmit and receive information on a high voltage electric network, which corresponds to the task set in the invention.

The presence of automatic adjustment of the level of response of the comparator in the claimed device, provided that the device address is added inside the frame, makes it possible to use it in the system of several similar devices, namely in the telemetry system of city power networks, where the network topology can be changed by operational switching.

Claims (3)

1. A device for encoding, receiving and transmitting digital information over electrical networks, comprising a signal converter equipped with at least two outputs, the input of which is an information input of the device, a transmitter equipped with two output keys, a receiver containing a detector and a comparator, a matching device and isolation, including a transformer with four windings, with the output winding connected to the electrical network, the receiving winding connected to the input of the receiver, and the other two to the output of the transmitter characterized in that the transmitter is additionally equipped with two amplifiers, the outputs of which are connected to the output keys, and the inputs are connected to the outputs of the signal converter, the detector is equipped with two diodes, an adder, inverting and non-inverting amplifiers, the inputs of which are connected to the receiving winding of the transformer of the matching device and isolation, and the outputs are connected to the inputs of the adder, and the output of the adder is connected to the input of the comparator, and the receiver is equipped with a unit for checking the reliability of the received information and, the input of which is connected to the output of the comparator, the additional output is connected to the additional input of the signal converter, and the other output is the information output of the device as a whole. 2. The device according to claim 1, characterized in that the receiver is additionally equipped with a digital-to-analog converter, and the inputs of the digital-to-analog converter are connected to additional outputs of adjusting the response level of the comparator of the validation block of the received information, and the output is connected to the control input of the comparator. 3. The device according to claim 1, characterized in that the output winding of the transformer of the matching and decoupling device is connected to the electric network through a high-voltage isolation capacitor.