JPS6147453B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a frame synchronization method for a remote monitoring system in which a monitoring signal is constantly cyclically transmitted twice and collated with an NRZ equal-length code. This is related to the method used.

Conventionally, the synchronization method for monitoring signals in this type of remote monitoring system is, for example, a synchronization code in which 12 bits are continuously "1" (if the communication speed is 50 bit/sec, a signal in which 240 ms is "1"). A frame synchronization method has been used in which data is added and data is sent and received in synchronization with the timing. That is, as shown in FIG. 1, for example, it had a code structure consisting of a synchronizing signal 1 of which 12 bits were "1", two start bits, three parity bits, four stop bits, and data 5 to 8 of 8 bits.

Therefore, by adding a synchronization code to each frame, data becomes redundant, requiring logic for generating and detecting a signal in which 12 bits are continuously "1". Furthermore, since the length of one frame is determined by the stability of the clock frequency on the transmitting and receiving sides and the permissible distortion of the received code, there is a relationship between clock accuracy, transmission line distortion performance, and data redundancy.

The present invention makes use of the feature that the transmission format of the monitoring signal is always cyclic double transmission verification, and the first two consecutive transmissions of a frame are generated or verified at the stage of two consecutive transmissions. By configuring the bits by adding calculations to the 8 bits of the first consecutive transmission, the same data can be distinguished from other data that is retransmitted.
It is possible to detect the beginning of a frame without adding the above-mentioned synchronization code in which the 12 bits are ``1'' consecutively, and the frame synchronization code can be configured with only 8 bits handled by software, making it easy to use for clocks, etc. This provides a frame synchronization method that does not make data redundant regardless of hardware reasons.

That is, when configuring a synchronization code for a monitoring signal of a remote monitoring system, the present invention allows the data contents of the first and second consecutive transmissions of the first two consecutive transmissions of a frame to be used without adding a separate synchronization code. By making the data different with a certain relationship and configuring the same data to be distinguished from other data that is retransmitted, it is possible to treat the two consecutively transmitted data at the beginning of the frame as a synchronization code.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows an embodiment of the present invention, 2,
3 and 4 are start bit parity bits, 2 stop bits, 9 to 12 are 8 data bits, and one character is constructed by adding bits 2, 3, and 4 to the 8 data bits during P-S conversion. Except for characters including data 9 and 10, the same character is sent twice in a row. Data 8 bits 10 is the data of the first consecutive transmission + α
(Here, it is implemented with α = 1),
Unlike synchronous code 1, data 9 and 10 are handled as synchronous codes.

FIGS. 3 and 4 are examples of software implementation using the method of the present invention. The transmitting side sends data 9 at 13, and generates and sends the above data 10 at 14. Then, at 15 and 16, data 11,
12 is sent out, and the data contents are updated and sent out until the end of the data is detected in 17.

The receiving side inputs the first and second consecutive transmissions at steps 18 and 19, and checks the second consecutive transmission data = first consecutive transmission data + α at 20, and continues the above input and checking until the conditions match. This is repeated, and if they match, it means that a synchronization code has been detected, and the process advances to step 21 to process the data. From then on, until the end of the data is detected at 22, the data of the first and second consecutive transmissions are input at 23 and 24, and at 25, the data of the first consecutive transmission = the data of the second consecutive transmission is checked, and if they are equal. To Ba21,
If they are different, error processing is performed at 26 and the process proceeds to 22.

As described above, it has become possible to have a synchronization code generation and detection function independent of bits 2, 3, and 4.

As described above, the present invention has the effect of being able to recognize the beginning of a frame without adding a synchronization code of 1, and of facilitating software replacement. Furthermore, by changing the content of "α", information such as the presence or absence of a state change can be superimposed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional code structure, FIG. 2 is a diagram showing a code structure according to an embodiment of the present invention, and FIGS. 3 and 4 are flowcharts of processing performed using the method of the present invention. be. 1 is a synchronization signal in which 12 bits are "1", 2 is a start bit, 3 is a parity bit, 4 is a 2-bit stop bit, 5 to 12 are 8-bit data, and 13 is the first consecutive transmission at the beginning of a data group. Processing, 14 is the generation and sending process of the first consecutive data + α, 15, 16 is the sending process of the first and second consecutive data of the second and subsequent data groups, 17, 2
1 is the end detection processing of the data group, 18 and 23 are the input processing for the first consecutive transmission, 19 and 24 are the input processing for the second consecutive transmission, and 20 is the data for the second consecutive transmission = the data for the first consecutive transmission + α. Detection processing, 21 is data processing, 25 is detection processing of 2nd consecutive transmission data = 1st consecutive transmission data, 2
6 is error processing.

Claims (1)

[Claims] 1 The data contents of the first two consecutive transmissions of the first two consecutive transmissions of the data group are different from the second consecutive transmission with a certain relationship, and the data contents of the first two consecutive transmissions are different from the two consecutive transmission format in which the same data is retransmitted. A synchronization method characterized by handling continuous transmission data as a frame synchronization code.