JPS587958A - Detecting system for signal interruption - Google Patents

Abstract

PURPOSE:To precisely decide signal interruption in a repeater to be used for digital communication by applying a signal outputted from a discriminating and reproducing part and a signal obtained by delaying the phase of said output signal to a flip-flop (FF). CONSTITUTION:A signal (a) outputted from a discriminating and reproducing part 1, an equalizing amplifier part or a wave-shaping amplifier and a signal (b) obtained by delaying the phase of the output signal (a) by a delay circuit 3 are applied to FF2. When a data signal is inputted, its output signal (c) is DC and, at the time of signal interruption, the signal (c) is AC. By detecting the AC component, the signal interruption can be precisely decided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal disconnection detection method that can reliably detect a p signal disconnection in a repeater used for digital communication.

Repeaters used for digital communication include those with equalization amplification function (IR function), those with equalization amplification function and shaping amplification function (2R function), equalization amplification function, timing function, and identification function. Some have a reproduction function (3R function), and repeaters with a Q3R function are often used.

Generally, in repeaters for optical and coaxial digital communications, when a digital signal input interruption occurs, it is necessary to immediately disconnect the line in order to prevent the generation of noise in the output. This is specifically based on the following reasons.

(2) In optical digital communications, if the repeater input (rj signal) is cut off, the laser for signal transmission is driven unnecessarily by the total noise, which accelerates the deterioration of the laser diode.

■Optical and coaxial digital communication (in repeaters,
When there is no signal input, the secondary stage device malfunctions due to noise.

Conventionally, as a signal disconnection detection method in a repeater having a 3R function, a signal is output from a timing signal extraction tank circuit in a timing circuit.

A method has been used to determine whether a signal is disconnected by taking advantage of the occurrence of this phenomenon. However, in such a method, @
When the amount of noise output from the tank circuit is large when the signal is cut off, the difference in amplitude between when there is a signal input and when the signal is cut off is small, which makes it difficult to judge whether the signal is too cut off. Ta.

SUMMARY OF THE INVENTION An object of the present invention is to provide a signal disconnection detection method that can correctly determine whether a signal is present or disconnected even when there is a large amount of noise, in order to eliminate the above-mentioned drawbacks.

To achieve the above object, the present invention provides an output signal with regular timing when a data signal is input to the repeater, but when the signal is disconnected.

Focusing on the point that a random signal is output, the signal output from the 2 equalization amplification section, shaping amplification function, or identification reproduction section, and the signal whose phase of the output signal is delayed by a delay circuit,
If given to flip-flop.

The output signal is a direct current when a data signal is input, and is an alternating current when the signal is disconnected. Therefore, a signal disconnection detection method is used in which detection of this alternating current 3-molecule is a t+'j-sign.

Embodiments of the present invention will be described below with reference to the drawings.

1 is a block diagram of a signal disconnection detection method of a repeater having a 3R function according to an embodiment of the present invention, and FIG. 2 is a time chart showing the operation of a flip-flop. In the figure, 1 is an identification and reproducing unit, 2 is a flip-flop, 3 is a delay circuit, and 4
is a DC/AC determination circuit. The identification/reproduction unit 1 is configured to generate 1/2 of the peak value of the pulse equalized and amplified by the equalization amplification unit of the repeater.
The timing section extracts the pulse repetition frequency from the input pulse train and determines whether the fault 1 value set in Output. This output signal a is branched into two, one is directly applied to one input of the flip-flop 2, and the other is applied to the other input of the flip-flop 2 as a delayed signal via the delay circuit 3. added to C. Flip-flop 2 is D type flip 7
The 0-delay circuit 3, which is made up of 0-tubes (D-FF), has a data input terminal, C is its 4-clock input terminal, and has a delay phase angle greater than 0° and less than 360°. When there is a data signal input, the flip-flop 2 generates a DC signal output consisting of a low level or a no/no level,
When the signal is cut off, the input pulse train is not extracted at the timing section, so the output of the identification and reproduction section 1 becomes random noise. The output C of the flip-flop 2 is applied to a DC/AC signal determination circuit 4, and the level of the AC component is detected. In other words, the DC/AC l#1 signal determination circuit 4 consists of an average value detection circuit or a peak value detection circuit, etc., and detects the average value or peak value of the AC component in the signal input, and when it is above a certain level, the signal is rejected. generates a high level signal indicating disconnection,
When the level is below a certain level, a low level signal indicating the presence of data signal input is generated. In this way, the configuration shown in FIG. 1 can generate the detection signal d of the υ signal disconnection.

(5) in FIG. 2 shows the case where there is a signal input, and (B) shows the case where the signal input is disconnected. Also, in each case +a+b+QHd represents the signals a, b, c, d'9, respectively, shown in FIG. D-4i'
F2 reads the state of the signal a which is applied to the clock input terminal C when the signal is set to -1, which is -1, f at the data input terminal C, and outputs the state of the signal C at the output. is determined. When there is an input signal, the phase relationship between signals +ja and b is always constant, so the output signal C of D −F F 2
There is no change in the state of the output signal C, and the output signal C maintains either the low level or the no-no level.

In FIG. 2(A), the output signal C is kept at a low level, and therefore the signal d of the 14-current AC (S Monthly W circuit 4) is at a low level indicating that there is an input signal.On the other hand, the signal is disconnected. As shown in Figure 2 (X3), when the signal A applied to the clock input terminal C rises, the state of the signal a applied to the data input terminal is read, but since signal a is noise, The pulse width is not constant, and the signal read at the rising point of the signal becomes a low level, and the output signal C becomes an alternating current.As a result, the detection signal d of the DC/AC signal determination circuit 4 becomes a low level indicating that the signal is disconnected. become.

A block diagram of the relay signal disconnection detection system, and a time chart showing whether or not it works in a 4-pin VJ fritz flop.

The one with the same type as Figure 1 is the same as Figure 1, published in M14, 7j.
<t.

17- Q Jun-gyo in Chubu, Orthopedic State! Width↑fl'1'
During i71 plowing, at the threshold set to 1/2 of the peak value of the pulse frlled to equalization at the equal width part of the vessel, the pulse of the specified pulse width at the point exceeding 1 or i + lH. What? 7. Since the output pulse is the same as the output of the identification town raw sound 19 in Fig. 1, the operation is ti.
It is the same as that explained in FIG. 1 and FIG. 2.

The 51st number 1 is the equalization scale II of the application example of the present invention] 'j'1
FIG. 6 is a block diagram for detecting a signal disconnection at an output of 1 s, and is a time chart that does not show the operation of the IJ block flop. In the figure, 01", which has the same function as that in Figure 1, is indicated by the same - symbol. It is the Soshuso Chubu 1". The output waveform of the Soshuso Chubu 1" is an RZ waveform when it has a 2R function, but it is an IR,
In the case of the 3R function, it may be an NRZ waveform. In the case of an RZ waveform, the phase 7-angle to be delayed by the delay circuit 3 is from 00 within the phase angle corresponding to the width of the point below the threshold at the point exceeding the dark value threshold set to 1/2 of the peak value. Delays the phase of large values, NRZ
In the case of a waveform of The following operations are the same as those performed during the inter-song period in FIG. 1, 2-1.

As explained in detail above, according to the present invention, the IR function, 2R
A repeater having a 4&3 function and a 3R function is extremely effective because it can reliably determine a signal disconnection and generate a detection signal even when there is large noise.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a signal disconnection detection method of a repeater having a 3R function according to an embodiment of the present invention, FIGS. 2, 4, and 6 are time charts showing the operation of a flip-flop, and FIG. FIG. 3 is a block diagram of a signal disconnection detection method of a repeater having a 2R function according to an applied example of the present invention. FIG. 5 is a block diagram of a signal disconnection detection method in the case of detecting a signal disconnection at the output of the central part of the monk according to an applied example of the present invention. 8- In the figure, 1 is the identification and reproduction part, 1' is the orthopedic state central part, 1'' is the soju monk central part, 2 is the 7-lip flop, 3-digit series circuit, and the 4-digit DC/AC judgment circuit.

Claims (1)

[Claims] l In a repeater having equalization amplification, identification regeneration, and timing regeneration functions used in digital communication, the logic state is changed depending on whether the phase states of two operators at the same frequency match or do not match [2. A flip-flop is provided to generate an output indicative of the condition. The alternating current component in the output obtained by applying a signal output from the identification and reproducing section and a signal whose phase is delayed by more than Io degrees and less than 360 degrees by a delay circuit to the flip 70 tube. A signal disconnection detection method characterized by detecting. 2. In repeaters with equalization amplification and shaping amplification functions used in digital communications, a flip-flop is used that changes the logic state depending on whether the phase states of two inputs of the same frequency match or do not match, and generates an output indicating the state. The alternating current component in the output obtained by applying the signal output from the middle part of the shaping section and the signal whose phase is delayed by p greater than 0 degrees and smaller than 360 degrees by a delay circuit to the seven lip-flops is calculated. A signal disconnection detection method characterized by detecting. 3. A vertical amplifier having at least an equalization amplification function used in digital communication is equipped with a flip-flop that changes the logic state depending on the match or mismatch of the phase states of two inputs of the same frequency and generates an output indicating the state. Within the phase width of the rising and falling edges of the signal output from the equalization amplifier and the threshold value of the output signal, and wider than 0 degrees (3601i
The signal is delayed by a smaller delay circuit. A signal disconnection detection method characterized by detecting an alternating current component in the output obtained by applying it to the flip-flop.