JPH04280133A - Data transmission system - Google Patents

Abstract

PURPOSE:To operate the system by having only to mount only one basic clock oscillator to one complete set of the full duplex data transmission system. CONSTITUTION:The data transmission system in which a data is sent from one equipment to the other equipment as a serial data uses a transmission line code by which a clock is extracted from the signal, the transmission system of the one equipment converts the data into the transmission line code synchronously with the basic clock generated by a basic clock oscillator and sends the resulting data, and the other equipment extracts the clock from the received transmission line code and uses the clock as the basic clock of the other equipment to activate the transmission system of the equipment and the basic clock oscillator is mounted only to the transmission system of the one equipment as the feature. Since the basic clock oscillator is mounted only to the transmission system of the one equipment, the increase in the cost of the basic clock oscillator generating the basic clock attended with the high speed data transmission is suppressed and the mount space of the basic clock oscillator is reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for supplying a clock for signal transmission in a data transmission system that transmits data as serial data from one device to another.

0002

2. Description of the Related Art FIG. 2 is a block diagram showing the configuration of a conventional full-duplex data transmission system. On the device A side shown in the figure, 1 is a transmitter for sending a signal onto the transmission path 6, 2 is an encoding device for converting a data string to be transmitted into a transmission path code in a format that allows timing extraction, and 3
4 is a basic clock oscillator that generates the timing for transmitting the data converted by the encoder 2 and sent as serial data; 4 is a receiver that receives the serial data flowing on the transmission path 7; and 5 is a signal that the receiver 4 receives. A decoding device 6 and 7 are serial data transmission lines for decoding the data and extracting a basic clock from the data. Further, on the device B side shown in the figure, parts indicated by the same symbols as those on the device A side have the same functions, and the explanation thereof will be omitted.

Next, the operation of the conventional full-duplex data transmission system will be explained. Data input to the encoding device 2 of the device A is converted into a transmission line code in synchronization with the basic clock generated by the basic clock oscillator 3. Commonly used transmission path codes include Manchester code and CMI code. The data converted into a transmission path code as described above is sent by the transmitter 1 from the device A to the transmission path 6 as serial data that can sufficiently drive the receiver 4 on the receiving side of the device B. Data input from the transmission line 6 to the device B is input to the decoding device 5 via the receiver 4. The decoding device 5 decodes the data converted into the transmission path code and extracts the timing of the same basic clock as that generated by the basic clock oscillator 3 of the device A. Such a method of extracting the timing of the basic clock is disclosed in, for example, Japanese Patent Laid-Open No. 63-76638 and Japanese Patent Laid-Open No. 2-13104.
It is disclosed in Publication No. 2. The data decoded by the decoding device 5 is subjected to serial-to-parallel conversion etc. by using the basic clock extracted as described above. Furthermore, data transmitted from device B to device A also performs the same operation as above via transmission path 7.
A description of this operation will be omitted.

0004

[Problems to be Solved by the Invention] Since the conventional full-duplex data transmission system described above is configured as described above, the basic clock oscillator 3 that generates the basic clock
had to be provided for each transmission system of device A and device B. Therefore, in a data transmission system that transmits data between device A and device B, the basic clock is becoming faster as the data to be transmitted becomes faster, and the cost of the basic clock oscillator 3 is increasing. The problem was that it was expensive. Further, when the basic clock oscillator 3 is a crystal oscillator, there is a problem that a high frequency cannot be obtained as the basic frequency, and a multiplier circuit is required, which increases the mounting space.

The present invention was made to solve the above-mentioned problems, and provides a data transmission system that can be operated by installing only one basic clock oscillator per full-duplex data transmission system. The purpose is to provide a system.

[0006]

[Means for Solving the Problems] A data transmission system according to the present invention uses a transmission line code that can extract a clock from a signal, and in a transmission system on one device side,
The data is converted into the above-mentioned transmission line code in synchronization with the basic clock generated by the basic clock oscillator and transmitted, and the other device side extracts the clock from the received transmission line code and uses this clock to the other device side. The basic clock is used as a basic clock to operate the transmission system of the device, and the basic clock oscillator is installed only in the transmission system of one of the devices.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a full-duplex data transmission system according to an embodiment of the present invention. On the device A side and the device B side shown in the figure, 1 is a transmitter for sending a signal onto the transmission path 6 or the transmission path 7;
2 is an encoding device that converts the data string to be transmitted into a transmission line code in a format that allows timing extraction; 3 is a basic clock oscillator that generates timing for sending out the transmitted data converted by the encoding device 2 as serial data; 4; 5 is a receiver that receives serial data flowing on the transmission path 7 or transmission path 6; 5 is a decoding device that decodes the data received by the receiver 4 and extracts a basic clock from the data; 6 and 7 are serial A data transmission path 8 is an idle pattern generating device that generates idle pattern data when there is no valid data to be transmitted. In the data transmission system according to the present invention, as shown in FIG. 1, the basic clock oscillator 3 that generates the basic clock is provided only in the transmission system of one device, which is the device A side.

Next, the operation of the full-duplex data transmission system according to the embodiment of the present invention will be explained. As shown in FIG. 1, the side with the basic clock oscillator 3 is called device A, and the side without it is called device B. Now, consider the case where data is transmitted from the device A side to the device B side. The data input to the encoding device 2 of device A is transmitted to the basic clock oscillator 3.
is converted into a transmission line code in synchronization with the generated basic clock. If there is no data to be sent to the encoding device 2, idle pattern data such as “01010101” is input from the idle pattern generator 8 to the encoding device 2, and the data is sent to the basic clock oscillator in the same way as the above data. 3 is converted into a transmission path code in synchronization with the generated basic clock. The data encoded in this manner and the idle pattern data are sent by the transmitter 1 from the device A to the transmission line 6 as serial data that can sufficiently drive the receiver 4 on the receiving side of the device B. Data input from the transmission line 6 to the device B is input to the decoding device 5 via the receiver 4. The decoding device 5 decodes the data converted into the transmission path code, and also decodes the data converted into the transmission path code.
The timing of the same basic clock as that generated by the basic clock oscillator 3 of is extracted. Device B as described above
Because data or idle pattern data is always input to the receiving side of the device so that timing can be extracted, the timing output from the decoding device 5 on the device B side is equivalent to the output from the basic clock oscillator 3. Therefore, when transmitting data from device B to device A, the timing output from the decoding device 5 on the device B side is supplied to the encoding device 2 as a basic clock. Therefore, in the data transmission system of the present invention, the basic clock oscillator 3 only needs to be installed in the transmission system of one of the devices, device A.

[0009] In the data transmission system described in the above embodiment, the transmission line medium for the transmission lines 6 and 7 is not only a general electrical connection device using a coaxial cable, but also an optical fiber. It can also be fully applied to optical connection devices.

0010

As described above, according to the data transmission system of the present invention, a transmission line code that can extract a clock from a signal is used, and the transmission system on one device side transfers data to the basic clock. Synchronizing with the basic clock generated by the oscillator, it is converted into the transmission line code and transmitted, and the other device extracts the clock from the received transmission line code,
This clock is used as the basic clock of the other device to operate the transmission system of that device, and the basic clock oscillator is installed only in the transmission system of one device, so the data to be transmitted can be transmitted at high speed. The increase in the cost of the basic clock oscillator that generates the basic clock due to the increase in the basic clock can be suppressed, and the mounting space for the basic clock oscillator has increased. It has the excellent effect of being able to be reduced in size.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a full-duplex data transmission system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of a conventional full-duplex data transmission system.

[Explanation of symbols]

1 Transmitter 2 Encoding device 3 Basic clock oscillator 4 Receiver 5 Decoding device 6 Transmission line 7 Transmission line 8 Idle pattern generator

Claims (1)

[Claims] Claim 1: A transmission line code from which a clock can be extracted from a signal is used, and data is transmitted to the transmission system of one device in synchronization with a basic clock generated by a basic clock oscillator. and means for converting the idle pattern data into the transmission path code and transmitting it in synchronization with the basic clock when there is no valid data to transmit, and the other device side includes means for converting the idle pattern data into the transmission path code and transmitting it in synchronization with the basic clock, While decoding the data converted from the received transmission path code,
A means for extracting a clock from the transmission line code and using the extracted clock as a basic clock on the other device side to operate the transmission system on the device side, A data transmission system characterized by being implemented only in the system.