JPS63198431A - Method for transmitting auxiliary signal - Google Patents

Abstract

PURPOSE:To transmit a master signal superimposingly while the transmission quality of an auxiliary signal is ensured by applying periodical violation to a coding side at a prescribed interval corresponding to one level of the auxiliary signal and adhering to the coding side to other level. CONSTITUTION:A master signal clock (a) is frequency-divided by a frequency division circuit 3 and a signal (b) having a period of n-bit is fed to an AND gate 4 together with an input auxiliary signal (c). A pulse of 1-bit is generated at each n-bit when the signal (c) is logical 1 from an output (d) of the gate 4 and no pulse is generated when the signal (c) is logical 0. In inputting the signal (d) to a CRV control input terminal 14 of a 1B2B coding circuit 1, a master signal (e) outputted from the circuit 1 is subjected to coding side violation periodically at each n-bit when the signal (c) is logical 1 and is not subject to coding side violation when the signal (c) is logical 0 so as to ensure the transmission quality of the auxiliary signal thereby transmitting the signal superimposedly onto the master signal while ensuring the transmission quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an auxiliary signal transmission method in which an auxiliary signal is superimposed on a main signal and transmitted in a digital transmission system using a 1B2B code as a transmission line code.

〔overview〕

In a method of transmitting an auxiliary signal by superimposing it on a main signal using a 1B2B code, the present invention periodically violates the encoding rule at regular intervals corresponding to one level of the auxiliary signal, and On the other hand, by adhering to the coding rules, it is possible to secure the same auxiliary signal transmission quality with a simple circuit configuration as with the method of constructing a frame on the main signal and superimposing the auxiliary signal using violation of the coding rules. It has been made possible.

[Conventional technology]

In general, in digital transmission systems, in addition to the main signals that should be transmitted, it is also possible to transmit signals at a lower speed than the main signals as auxiliary signals, such as meeting telephone lines and transmission line switching signals, which are necessary for maintenance and operation of the system. required. Methods for transmitting such auxiliary signals are classified into methods of transmitting using a line separate from the main signal and methods of transmitting by superimposing them on the main signal, but there are various methods such as economical efficiency and method flexibility. From the point of view,
The latter method is often used. Generally, the auxiliary signal is a low-speed digital signal that is asynchronous to the main signal, so
The auxiliary signal is once sampled at multiple points using a signal synchronized with the main signal, and then superimposed on the main signal. Furthermore, in general, the main signal is often converted into an appropriate transmission line code before being transmitted to ensure stable transmission characteristics.

Methods for superimposing the auxiliary signal on the main signal include time-division multiplexing of the auxiliary signal on the main signal, and information on the auxiliary signal that violates the code rule of the main signal (Code Rule Violation).
ation: Hereinafter referred to as CRV. ) is known. In particular, when a 1B2B code such as CM1 is adopted as a transmission line code, it is generally widely used because the superimposition of auxiliary signals by CRV is superior in terms of circuit scale.

In this type of system, auxiliary signal information is detected by performing CRV detection on the receiving side, but in order to specify the temporal position of the superimposed auxiliary signal, an example shown in Fig. 3 is used to detect auxiliary signal information. , the frame is constructed. That is, a frame is constructed by inserting a frame bit (F bit) that causes CRV periodically on the main signal, and a specific bit within the frame is assigned to the auxiliary signal bit. In the auxiliary signal bit, when the auxiliary signal is "1", there is a CRV, and when the auxiliary signal is "0", there is no CRV, so that the auxiliary signal is superimposed on the main signal.

FIG. 4 shows an example of a circuit configuration using this method, and the frame generated by the frame generation circuit 17 on the transmitting side is 1B
It is added to the CRV control human power 14 of the 2BB duplication circuit 1 and superimposed on the main signal. On the receiving side, a frame synchronization circuit 18
The frame bit is detected, the position of the auxiliary signal bit is specified, and the reading circuit 19 determines whether there is a CRV for that bit and reproduces the auxiliary signal information.

[Problem that the invention seeks to solve]

In this conventional method of superimposing auxiliary signals using CRV, frame synchronization is achieved, so even if an error occurs in the transmission path, it is possible to reproduce the auxiliary signal relatively accurately.
It is necessary to add a frame generation circuit on the transmitting side and a frame synchronization circuit on the receiving side. All of these circuits have a circuit scale larger than that of the main signal 1B2BB2 converting/decoding circuit itself, and have the disadvantage that the circuit scale of the transmitting/receiving circuit increases considerably, which impairs the advantages of the 1B2B code.

SUMMARY OF THE INVENTION The present invention aims to eliminate such drawbacks and to provide an auxiliary signal transmission method that can maintain high auxiliary signal transmission quality with a simple circuit configuration.

[Means for solving problems]

The present invention provides a method of superimposing a binary digital signal having a speed sufficiently lower than the speed of the main signal as an auxiliary signal on a main signal using a 1B2B code, and transmitting the auxiliary signal. When the signal exhibits one level, periodic violations of the 1B2B encoding rule of the main signal are given at regular intervals, and when the signal exhibits the other level, the 1B2B encoding rule of the main signal is observed. A feature is that this binary digital signal is superimposed as an auxiliary signal.

[Effect]

For example, for the 1B2B encoding of the main signal, the auxiliary signal is
If the auxiliary signal is "1", a coding rule violation is given periodically at regular intervals, and if the auxiliary signal is "0", the auxiliary signal is superimposed on the main signal and transmitted by controlling so as not to give a coding rule violation. .

〔Example〕

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

FIG. 1 is a circuit configuration diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a waveform diagram showing the waveforms of signals at various parts of this embodiment.

The main signal clock a is frequency-divided by a frequency divider circuit 3, resulting in a signal having a period of n bits. This signal S is applied to the AND gate 4 together with the input auxiliary signal C, and its output d is
When the auxiliary signal is "1", a 1-bit pulse is generated every n bits, and when the auxiliary signal is "0", no pulse is generated. If this signal d is input to the CRV control input terminal 14 of the 1B2BB dualization circuit 1, the main signal e output from the 1B2BB dualization circuit 1 will be n if the auxiliary signal is "1".
If the auxiliary signal is "0", the auxiliary signal information is superimposed on the main signal, but n >
By selecting 1, it is possible to transmit the auxiliary signal without affecting the transmission characteristics of the main signal.

On the receiving side, CRV detection is performed simultaneously with decoding of the main signal in 1B2B decoding/decoding 2, and a signal f is obtained at the CRV detection output terminal 15. A pulse width expansion circuit 8 expands the pulse width of this signal f to n bits, and a retiming circuit 9 performs waveform reproduction using the main signal clock to obtain an auxiliary signal g. On the other hand, if an error occurs in transmission line 1G,
An extra pulse with a pulse width of n bits is generated in the waveform of the auxiliary signal g.

Generally, the repetition period of the auxiliary signal is sufficiently large compared to the n-bit pulse width, so by appropriately setting the cutoff frequency of the low-pass filter 10, surplus pulses can be removed without significantly deteriorating the auxiliary signal data. It can be suppressed. Therefore, the auxiliary signal output terminal 13 is supplied with the auxiliary signal g, which does not deteriorate even if a certain amount of transmission path error occurs.
is obtained.

As described above, according to the auxiliary signal transmission method used in this embodiment, a conventionally used asynchronous low-speed digital signal is sampled at multiple points, a frame is constructed on the main signal, and the auxiliary signal is superimposed by CRV. It is possible to ensure almost the same auxiliary signal transmission quality as the method using this method. Further, the circuit configuration can be realized with an extremely simple circuit compared to the case where a conventional frame generation circuit, frame synchronization circuit, etc. are added.

〔Effect of the invention〕

As explained above, in the present invention, the auxiliary signal is "1" (
or "0"), the 1B2B coding rule of the main signal is periodically violated at regular intervals, and the auxiliary signal becomes "0".
(or "l"), by controlling so as not to violate the coding rules, it is possible to maintain almost the same transmission quality as the conventional method of configuring frames and superimposing auxiliary signals, and to maintain a small size. This has the effect of being able to perform superimposed transmission of auxiliary signals on a circuit scale.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a waveform diagram showing signal waveforms of each part shown in FIG. 1. FIG. 3 is a frame configuration diagram of a signal used in a conventional example. FIG. 4 is a block configuration diagram showing the configuration of a conventional example. ■...1B2BB 2nd circuit, 2...1B2B decoding/synthesizing circuit...frequency dividing circuit, 4...AND gate, 5...
...Main signal input terminal, 6...Clock input terminal, 7.
...Auxiliary signal input terminal, 8...Pulse width expansion circuit, 9
...Retiming circuit, 10...Low pass filter, 11...Main signal output terminal, 12...Clock output terminal, 13...Auxiliary signal output terminal, 14...CRV
Control input terminal, 15... CRV detection output terminal, 16.
...Transmission path, 17...Frame generation circuit, 18...
Frame synchronization circuit, 19...readout circuit.

Claims (1)

[Claims] (1) A method in which a binary digital signal having a speed sufficiently lower than the speed of the main signal is superimposed on a main signal using a 1B2B code as an auxiliary signal, and this auxiliary signal is transmitted. When exhibiting one level, periodic violations of the 1B2B encoding rule of the main signal are given at regular intervals, and when exhibiting the other level, the 1B2B encoding rule of the main signal is observed and this violation is applied. An auxiliary signal transmission method characterized by superimposing a binary digital signal as an auxiliary signal.