RU1830629C - System of cycle synchronization - Google Patents

Abstract

The invention can be used in digital discrete message transmission systems, including digital telephone communication systems. The purpose of the invention is to reduce the time it takes to synchronize a synchronization system in cycles. The loop synchronization system comprises a master and a slave station connected by a communication line. The master station contains the first transmit and receive regenerators 1 and 2, the first transmit clock sensor 3, the clock generator 4, the first distributor 5 receive cycles, the receive sync search unit 6, the synchronism lock unit 7. The slave station comprises second transmit and receive regenerators 10 and 11, a transmit clock sensor 12 and a receive cycle distributor 13. The goal is achieved by introducing a time interval at the master station 8 and a time meter 9, and at the slave station, the integrator 15, the controlled key 16, and the sync detector 14. 2 ill.

Description

The invention relates to digital discrete messaging systems, and in particular to digital telephone communication systems.

The aim of the invention is to reduce the time to enter synchronism.

The scheme of the proposed device is presented in figure 1; timing diagrams illustrating the operation of the device are shown in FIG.

The cycle synchronization system comprises a master and a slave station, interconnected by a communication line.

The master station comprises a first transmission regenerator 1 and a first reception regenerator 2, a first transmission clock sensor 3, a clock frequency generator 4, a first receive cycle distributor 5, a reception clock search unit 6.

synchronism locking unit 7, controlled switch 8, time interval meter 9. When this generator 4 clock frequency through the first sensor 3. clock transmission pulses is connected to the input of the managed switch 8, the output of which is connected to the input of the first transmission regenerator 1.

The control input of the managed switch 8 together with the control inputs of the first reception distributor 5, the time slot meter 9 and the reception clock search unit 6 is connected to the output of the synchronism lock unit 7, and the clock and information inputs of the first distributor 5 receive cycles, the meter 9 the time interval, block 6 search clock reception and block 7 lock synchronism are connected respectively to the output of the clock frequency

and the information output of the reception regenerator 2, the output of the reception clock search unit 6 being connected to the input of the synchronism fixing unit 7, In addition, the outputs of the synchronization fixing unit 7 and the clock generator 4 are connected to the transmission cycle distributor (not shown in FIG. 1), of the outputs of which, the information stream enters the input of the transmission regenerator 1 and further into the communication line.

The slave station contains a second reception regenerator 10, a second transmission regenerator 11, a second transmission clock sensor 12 and a second reception cycle distributor 13, a sync detection detector 14. integrator 15 and controlled key 16.

The output frequency of the reception regenerator 1.0 is connected to the inputs of the second transmission clock sensor 12, the detector 14 clocks and to the clock input of the second distributor 13 receive cycles. And the information output of the regenerator 10 is connected to the information inputs of the receive 13 distributor and the controlled key 16 and the input of the integrator 15, the output of which and the output of the sensor 12 of the transmission clock are connected respectively to. the first and second inputs of the controlled key 16. The output of the detector 14 is connected to the control input of the distributor 13 of the receive cycles, and its clock input and output of the integrator 15 are connected to the distributor of the transfer cycles (not shown in Fig. 1), The output of the controlled key 16 connected to the input of the transmission regenerator 11.

Clock generator 4, first and second transmit clocks 3 and 12, first and second distributors 5 and 13 receive cycles, receive sync search block b, synchronism lock block 7, first and second transmission regenerators 1 and 11, 1 first and second regenerators 2 and 10 of the reception have the same purpose and scheme as the analogous devices described above.

The time interval meter 9 provides counting of the number of clock intervals between two installation current-free pulses.

The managed switch 8 serves to transmit a line at the time of synchronization of the inverted sequence from the output of the first transmission clock sensor 3, i.e., it allows to obtain a synchronization sequence from the output sequence of the transmission clock sensor 3 (Fig. 2a).

The integrator 15 serves to determine the installation timing sequence in a group digital stream. entering terminal equipment.

The integrator has a rather long integration time and does not respond to the information digital stream, in which there is a change in current and currentless packages at neighboring positions. The integrator can be functionally implemented, for example, as an integrating RC chain with an integration time of at least half a cycle.

The sync detector 14 is designed to synchronize the second

5 of the distributor 13 reception cycles, it is similar to the second .12 clock sync sensor, but operates with a constant phase shift dependent on the given end equipment.

0 The claimed system operates as follows.

1. Work in synchronism.

From the distributor of the transmission cycles of the digital EATL (not shown in Fig. 1), a digital information stream is received. At the corresponding time instants, the synchronization clock pulses are mixed into it at the master station through the managed switch 8 from the first transmission clock sensor 3. The digital group stream through the first transmission regenerator 1 and the communication line enters the terminal equipment. ,

From the second regenerator 10 receiving slave station comes restored

5 digital group stream and clock frequency. The sync detector 14 operates synchronously with the received clock pulses. The second distributor 13 of the slave receiving cycles of the slave station operates synchronously with the distributor of the digital EATS transmission cycles. . . From the distributor of transmission cycles of the terminal equipment (not shown in Fig. 1), an information digital

5 stream

At the required times, the clock pulses are mixed from the second transmission clock sensor 12 through the controlled key 16 to it. Digital

0, the group stream through the second transmission terminal regenerator 11 and the communication line enters the digital EATL.

The reconstructed digital group stream and clock frequency enter the master station, which operates in synchronization mode similarly to the prototype.

2.Poter synchronism.

The principle of operation of the synchronization system when searching for synchronism after its loss is as follows.

Since the master and slave stations are synchronous devices, when working in synchronism, there is a certain time shift between the moment of sending the transmission clock signal from the master station to the slave station and the reception of the clock pulse in the slave (the station is from the slave station. If we consider the synchronization system from the point of view of the master station, it can be noted that the clock sent from the master station comes back with a certain delay, This delay is determined by the propagation time according to communication and phase relationships of reception (transmission of the slave station. It is important to note that this delay for each communication system is constant and when working in synchronism, the phase ratio of the reception / transmission of the station is taken into account (compensated). When synchronism is lost, the clock pulses arriving to the master station; the clocks sent from it cease to correspond in phase, i.e., an additional time shift appears between the hypothetical moment of return to the master station of the clock sent from it and the real moment By receiving a clock sent from the slave station to the master station. The search for synchronism, thus, can be reduced to measuring and compensating for the indicated additional time shift. This correction can be carried out.

a corresponding change in the timing of sending clock pulses from the master station with respect to the moments of arrival of the clock pulses, i.e., a change in the phase shift of transmitting / receiving the master station.

This is achieved as follows,

The loss of synchronism in the inventive system is recorded only in the master station. When synchronism is exited (due to the effect of interference on the line, surges of the supply voltage in the equipment, etc.), the reception clock search unit 6 ceases to be tuned to the received synchronization pulses. This is fixed by the synchronism lock unit 7 as a loss of synchronism. This control signal turns off the first distributor of 5 reception cycles and the distributor of transmission cycles of the master station, enters the search mode block 6 of the reception clock pulses into search mode, prepares a time interval meter 9 and switches the managed switch 8.

As a result, the inverse signal from the output of the first

sensor 3 transmission clock. This signal is an installation synchronization sequence and is a sequence of current transmissions (units) without pauses, in which currentless transmissions, (zeros) are present only at the positions of the clock pulses (Fig. 2a).

This sequence through the first transmission regenerator 1 and the communication line enters the terminal equipment.

From the second reception regenerator 10 in the slave station, the restored synchronization installation sequence is received. Since the last

consists almost of the current packages, then after a while at the output of the integrator 15, a control signal appears, which indicates a loss of sync. nizma in the system. This signal

the distributor 13 of the reception cycles and the distributor of the transmission cycles of the terminal equipment are switched off, and a controlled key 16 is turned on, to the first control input of which

ycTaHOBovmafl is a synchronization sequence, and to the second control input, there are clock pulses from the transmitter 12 clock pulses. Managed key 16 works in such a way that no-current

sending at its output in the TC only at times when it receives a transmission clock or a current-free transmission of the installation synchronization sequence (fig.2b).

The sequence from the output of the controlled key 16 through the second transmission regenerator 11 and the communication line will go to the master station.

It is obvious that the best-case package 1 corresponds to the position of the clock transmitted from the slave to the master station, and the best-current package 2 corresponds to the position of the clock transmitted from the master station and returning back.

This sequence after the first reception regenerator 2 is fed to a time interval meter 9, which determines the number of clock cycles between two currentless transmissions received on it

input. Obviously, this is the additional time shift of the DGD (clocks) (Figs. 2b and 2c), which must be compensated for entering synchronism. For this, information on the measured time shift from

the time slot meter 9 is transmitted to the first transmission clock sensor 3, as a result of which the next clock transmission clock is on the clock (clock) earlier.

Obviously, the sync pulses generated by the first sensor 3 of the sync pulses of the transmission of the master station at new positions will provide synchronism in the master station - slave station - master station system

8, as a result, the master station will enter an operation mode corresponding to the presence of synchronism. The transmit and receive cycle distributors are turned on, the controlled switch 8 will start switching the output of the first transmission clock sensor 3 again. As a result, a digital multicast stream with clock pulses will enter the communication line through the first transmission regenerator 1. As indicated above, in this stream there is an alternation of current and non-current transmissions, so the integrator 15 in the slave station will cease to give a control signal, and the slave station will switch to the state corresponding to the presence of synchronism.

The advantage of such a synchronization system compared to the prototype is its simplicity, due to the lack of a reception clock search block and a synchronism lock block in the slave station.

The main advantage of this synchronization system is the speed of synchronism search,

The time to search for synchronism in this system does not exceed the period of synchronization pulses. At an Fc frequency of 8 kHz, this time is 1

constitutes

8 X 103

 0, T25ms,

SUMMARY OF THE INVENTION A cycle synchronization system comprising a master station which includes a first transmission regenerator, a first reception regenerator and a clock generator, the output of which is connected to an input of a first transmission clock sensor and a first input of a transmission cycle distributor, and also a unit Search for clock pulses, a synchronism lock unit and a first distributor of receive cycles, the clock inputs of which are connected to the clock output of the first receive regenerator, the information output to connected to the information inputs of the reception clock search block and the synchronism lock block, the output of which is connected to the control input of the first receiver of the receiving cycles distributor

and the second input of the first distributor of the transmission cycles, and the input of the synchronization fixing unit is connected to the output of the reception clock search unit, and the slave

a station comprising a second reception regenerator and a second transmission regenerator connected via a communication line to a first transmission regenerator and a first reception regenerator, respectively;

as well as a second transmission clock sensor and a second reception cycle distributor, the clock inputs of which are connected to the clock output of the second reception regenerator, the information output of which is connected to the information inputs of the second reception cycle distributor and the second transmission cycle distributor, characterized in that, in order to reduce time to enter

synchronism, at the master station, a time interval meter and a controlled switch are introduced, the input and output of which are connected respectively to. the output of the first transmission clock sensor and

the input of the first transmission regenerator, a. the control input of the managed switch is connected to the control inputs of the time interval meter and the reception clock search unit and to the output of the synchronism lock unit, the information inputs of the first distributor of receive cycles and. the time interval meter is connected to the information output of the first reception regenerator, the clock output of which is connected to the clock input of the time interval meter, the output of which is connected to the second input of the first transmission clock sensor, and on the slave station

introduced integrator, controlled key and. The synchronization detector, the input and output of which is connected respectively to the clock output of the second receive regenerator and the control input of the second distributor of receive cycles, the inputs of the integrator and the controlled key are connected to the information output of the second receive regenerator, the first and second, control inputs of the controlled key

connected respectively to the output of the integrator and to the output of the second transmission clock sensor, the output of the controlled key is connected to the information input of the second transmission regenerator, and the output of the integrator is connected to the other input of the second transmission cycle distributor.

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