JPS6386640A - Data communication equipment - Google Patents

Abstract

PURPOSE:Not to interfere with data communication and to fully execute the communication even at the time of connecting in multi-link by removing jitter components in reproduced data. CONSTITUTION:The data having the jitter components is written in a bit buffer circuit 6 and read out with a free run clock which has nearly equal frequency to a write clock frequency(data speed) so as to remove the jitter of the reproduced data. in this case a bit slip in the bit buffer circuit 6 is caused by the shift of frequency between the write clock and the read clock but the bit slip can be prevented by interposing signal pause sections at intervals of a certain time in a transmitted signal which comes from a data terminal device and is stored in a memory 3 for a while to be transmitted to a transmission line 11 in the transmission part 1 of a transmission-reception device for transmitting data. Thus there is no interference in the data communication and even if the transmission reception device for transmitting data is connected in the multi-link, it is evaded that the communication is made impossible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data communication device, and particularly to a data communication device for data communication between data terminal devices.

[Conventional technology]

Generally, data communication between data terminal devices is performed by installing a data transmission transmitting/receiving device nearby and communicating via a transmission path. The data transmission transmitting/receiving device sends data from the data terminal device to the transmission path, and the opposing data transmission transmitting/receiving device regenerates the data signal from the transmission path and outputs it to the data terminal device.

[Problem that the invention seeks to solve]

However, in the conventional data transmission transmitter/receiver described above,
There is a jitter component in the reproduced data, and in a system where data communication is performed via a data transmission transmitter/receiver as described above, if there is a jitter component in the reproduced data reproduced by the receiving section in the data transmitter/receiver, this will occur. This poses a serious problem in that data communication is hindered, and in particular, when multiple links are connected, normal communication may not be ensured.

In other words, when the transmission distance becomes longer than the data reproduction capability of the data transmission transmitting/receiving device, the device is connected in series as a relay device (in this case, jitter increases each time the data signal passes through each device). However, there is a risk that normal communication will eventually become impossible.

An object of the present invention is to solve the above-mentioned problems in a system that performs data communication between data terminal devices.

[Means for solving problems]

The data communication device of the present invention is a data communication device that performs data communication between data terminal devices, and temporarily stores data arriving from the data terminal device in a memory, and sends out a signal with a signal pause section at regular time intervals. The present invention is characterized by comprising a transmitting section that performs the following operations, and a receiving section that includes a pit buffer circuit that eliminates jitter components of reproduced data.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block configuration diagram of an embodiment of the present invention, in which only one direction of data signals is shown for convenience in a system in which data communication between data terminal devices is performed via a data transmission transmitting/receiving device.

In FIG. 1, transmitting section 1. The receiving unit 2 is a transmitting unit and a receiving unit of a transmitting and receiving device for data transmission, respectively, and these are connected to the transmission path 1.
They face each other via 1.

The transmitting section 1 has a modulating section 4 for data transmission, and the receiving section 2 has a demodulating section 5 for data transmitting. 4 to the transmission path 11, and is supplied to the demodulator 5 of the receiver 2 of the opposing data transmission transmitter/receiver, where the receiver 2 reproduces and outputs it.

The reproduced data is output to the data terminal device or, if the data transmission transceiver is connected to multiple links, is further transmitted to the opposing data transmission transceiver.

The transmitter 1 is provided with a memory 3, and the receiver 2 is provided with a pit buffer circuit 6 and an oscillator 7.

8.14 are received data and reproduced data lines, respectively; 9.15 are timing clock lines for received data and reproduced data, respectively; the received data is supplied to the memory 3, where it is stored at - hours, and the reproduced data is sent to the focus buffer circuit. It is taken out from 6.

10 and 12 are memory 3. The output of the pit buffer circuit 6 is an input signal line; 13 is a timing clock line for the jittered input signal line 12 signal extracted from the signal on the transmission line 11 by the demodulator 5; and 16 is a control line.

The control line 16 is used to prevent an overflow of the memory 3, and is a control line 4'n for requesting the data terminal to stop transmitting data.

Data communication between data terminal devices is performed via a data transmission transmitting/receiving device. In this case, the device having the configuration shown in FIG. In this case, the pit buffer circuit 6 eliminates jitter components of reproduced data.

That is, by writing data with a jitter component into the pit buffer circuit 6 and reading it out using a free rank clock having a frequency approximately equal to the write clock frequency (data speed), a shifter for reproduced data is eliminated.

At this time, focus slip in the pit buffer circuit 6 due to the frequency difference between the write clock and the read clock becomes a problem, but in the transmitting section of the data transmitting/receiving device, the data is temporarily stored in the memory 3 coming from the data terminal device and then transmitted. Pit slips are prevented by placing signal pause sections at regular time intervals in the signal sent to road 11.

FIG. 2 is an explanatory diagram of the operation of the structure shown in FIG.
FIGS. 2(a), (b), and (c) show the received data line 8 of FIG. 1, respectively. Output signal line 10. It corresponds to each signal on the reproduction data line 14. 2(C) (2) is a case where the frequency of the timing clock 9 is lower than the frequency of the oscillator 7, and FIG. 2(c) (2) is the opposite case. In FIG. 2(b), T is a data transmission suspension period, and this data transmission suspension period T prevents bit slips occurring in the pit buffer circuit 6.

In this way, in a system in which data communication between data terminal devices is performed via data, data arriving from the data terminal device is temporarily stored in the memory 3 in the data transmission transmitting/receiving device, and a sending signal is sent between the data transmitting/receiving devices. A transmission signal pause period T is placed at regular time intervals in the data terminal to eliminate jitter components of the reproduced data output to the data terminal device.

In this way, the shifter component of the reproduced data can be eliminated in communication between data terminal devices,
Jitter components can be removed so that they do not interfere with data communication. Even if the data transmission transmitting/receiving device is connected as a relay device, it is possible to eliminate the risk that jitter will increase each time the data transmission transmitting/receiving device passes and normal communication will not be possible. Even when data transmission transmitting/receiving equipment is connected to multiple links, such as when the transmission distance of a road section is long, it is possible to avoid such situations where communication is impossible because the communication method does not have jitter components. .

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to eliminate jitter components in reproduced data in data communication between data terminal devices, so that data communication can be prevented from interfering, even if It is possible to ensure sufficient communication even when a link is connected.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the operation of FIG. 1...Transmitter 2...Receiver 3...Memory 4...Modulator 5...Demodulator 6...Bit buffer circuit 7... ...Oscillator 11 ...Transmission line

Claims (1)

[Claims] (1) In a data communication device that performs data communication between data terminal devices, a transmitting unit that temporarily stores data arriving from the data terminal device in a memory and sends out a transmission signal with a signal pause section at regular time intervals; 1. A data communication device comprising: a receiving section having a bit buffer circuit for eliminating jitter components of reproduced data.