JPS6162238A - Switching signal generating circuit - Google Patents

Abstract

PURPOSE:To attain stable switching operation by designing the titled circuit that no switching signal is generated so long as a state is not consecutive for a prescribed time or over that one of an active device and a spare device generates an alarm signal and the other does not generate the alarm signal. CONSTITUTION:An intermittent alarm signal generated due to the deterioration in quality of a line is inputted respectively to alarm signal input terminals 1 and 2 at active and spare devices, and it is led to retriggerable multivibrator circuits 3, 4 as a consecutive signal when the time from the stop of alarm till the generation of alarm again is within a prescribed time and the output appears at points A2, B2. The signal is branched into two at the points A2 and B2 and the branched signal is outputted to a point C1. The signal is branched into two at a point C2; one is led directly to an AND circuit 9 and the other is inputted to a reset input terminal of the counter circuit 8 in order to prevent the output if the difference in the alarm signal is not consecutive for a prescribed time. The switching signal is transmitted to the switching circuit of a transmission line respectively from output terminals 14 and 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention uses intermittent pulse-like notification signals generated from redundant communication equipment to determine the frequency of occurrence of alarm signals of working equipment and standby equipment. The present invention relates to a switching signal generation circuit for generating a stable switching signal in response to a switching signal.

(Prior art) In general, communication equipment often adopts a standby system for equipment in consideration of reliability and maintainability, and the D-axis signal generated from the communication equipment is used as the switching signal between the active equipment and the standby equipment. are using.

However, due to deterioration of the communication line (for example, deterioration of the carrier level or increase in the amount of noise), the alarm signal is generated intermittently near the set point where the -axis signal is generated. This often occurs. Therefore, if this heel good news signal is directly used as a switching signal for the active and backup route, the switching operation will be performed more frequently than necessary every time an alarm signal occurs.

As a circuit aiming to solve this problem, there is a music signal conversion circuit proposed by the inventor of the present invention.
208005). This circuit does not use the alarm signal as it is as a switching signal, but uses a pulse waveform shaping circuit and a pulse delay circuit to handle the intermittently occurring good news signal, even if the occurrence time is short but the occurrence frequency is high. is capable of transmitting such an alarm signal as a stable switching signal, and
The configuration is such that the transmission of the switching signal can be selected depending on the duration of the alarm signal.

(Problem to be Solved by the Invention) The above circuit does not perform unnecessary high-frequency switching operations compared to the case where the alarm signal is used as a switching signal as it is, but there is still variation in the settings of the alarm signal generation circuit. ,or,
Depending on variations in the settings of the pulse waveform shaping circuit and pulse delay circuit, unnecessary switching operations may occur.

In other words, due to the deterioration of the communication line, the alarm signal of the active device is generated earlier than that of the backup device due to variations in setting values, and the alarm signal input to the jurisdiction signal conversion circuit is generated earlier than that of the protection device due to variations in setting values of the pulse delay circuit. If the alarm signal conversion circuit on the working side generates the f-axis signal earlier than the standby side, an unpleasant switching of the communication equipment from the working side to the standby side will occur, even though an alarm signal will eventually be generated on the standby side as well. I'm done. Conversely, if the quality of the communication line is restored and the good news signal input to the active device is released earlier than the backup device due to variations in the settings, and due to errors in the settings of the pulse waveform shaping circuit, If the working side good news signal conversion circuit cancels the obituary signal sooner than the standby side, the good news signal will eventually be canceled on the standby side as well, but unnecessary switching from the standby side to the working side equipment will occur. will be carried out.

Therefore, as long as there are variations in the current and standby axis setting values, switching using alarm signals related to line quality has the drawback of causing unnecessary switching operations.

(Means for Solving the Problems) An object of the present invention is to enable stable switching between the active equipment and standby equipment even in the case of intermittent alarm signals caused by deterioration of line quality. An object of the present invention is to provide a complete switching signal generation circuit that compares alarm signals of standby equipment and sends a switching signal for switching a line to equipment that occurs less frequently and has a shorter duration.

The present invention has the following structure to achieve the above object.
- have. That is, if the next rectangular wave signal appears as an input within a preset time after one input rectangular wave signal ends, the previous rectangular wave signal and the next rectangular wave signal are consecutively combined into one. two retriggerable multi-circuits (a first retriggerable multi-circuit and a second retriggerable multi-circuit) that output a rectangular wave signal, and the outputs of the two retriggerable multi-circuits are each inverted. Two inverters (
a first inverter and a second inverter), an exclusive OR circuit that detects a difference between the outputs of the two retriggerable multi-circuits, and a rising edge and a falling edge of the output waveform of the exclusive OR circuit; a counter that generates a waveform signal that rises after a predetermined period of time has elapsed; a first AND circuit that ANDs the output signal of the counter and the output signal of the exclusive OR circuit; a second AND circuit that takes the AND of the output signal and the output signal of the first inverter; and a second AND circuit that takes the AND of the output signal of the first AND circuit and the output signal of the second inverter; and a third AND circuit that receives the output signal of the second AND circuit and the output signal of the third AND circuit, and receives the output signal of the second AND circuit and receives the output signal of -1 when the output signal rises; This switching signal generation circuit includes a flip-flop circuit that generates a falling rectangular wave signal.

(Function) The operation of the switching signal generation circuit of the present invention is as follows. Pulsed good news signals are input to the input ends of the two retriggerable multi-circuits, one from the current equipment and the other from the standby equipment. A retriggerable multi-circuit outputs a plurality of pulse signals that come in at time intervals less than a certain value (eg, t, I) as one continuous wide pulse. That is, a signal that is repeatedly generated at a frequency higher than a certain level is regarded as a continuous θ signal. The two series e obtained in this way
Both signal signals are applied to an exclusive OR circuit. A signal appears at the output of the exclusive OR circuit only when an alarm signal is generated in one of them and not in the other. If both the active equipment and the standby equipment are emitting an alarm, or if both are not emitting an alarm, there is no need to switch between active and standby equipment, so one of them will have jurisdiction and the other will issue an alarm. It is only necessary to detect a case where there is no one, that is, a case where the current and standby are different.The exclusive OR circuit detects such a state.

Further, the output of the exclusive OR circuit is applied to the first AND circuit and the counter circuit.

When the output appears in the exclusive OR circuit, the counter circuit remains at a low level for a predetermined period of time (for example, 1.
) automatically outputs a signal that becomes high level.

This output signal is applied to the first Q AND circuit and ANDed with the output of the exclusive OR circuit. The meaning of this AND signal indicates that the difference between the current equipment and the standby equipment regarding the occurrence of an alarm has continued for a predetermined period of time. In other words, if different states continue for a certain period of time, 1
It is used as a signal to check when switching is performed for the first time. The li output signal of the first AND circuit is branched into two branches and applied to the second AND circuit and the third AND circuit. -10,000 The output signal of the first Gable multi circuit is applied to the second AND circuit with its polarity inverted by the first inverter. Similarly, the output signal of the second NOR triggerable multi-circuit is applied to the third AND circuit after its polarity is inverted by the second inverter. The polarity of these signals is reversed, so that when the signal is low (ie, at a high level), it indicates a state in which there is no alarm signal, that is, a normal state. Therefore, by performing an AND with the output signal of the first AND circuit, when the state in which the -10,000 line issues a write @ and the other line does not issue an alarm continues for a certain period of time,
Of the second AND circuit and the third AND circuit, the output of the AND circuit in the series that is not issuing an alarm is at a high level, and the output of the AND circuit in the series that is issuing a warning is at a low level. Become.

These two output signals are applied to a 7 lip-flop circuit. A flip-flop circuit generates a rectangular wave signal whose polarity is reversed by reversing the high and low levels, or polarities, of two applied signals. The rectangular wave signal thus obtained is used as a switching signal between the current equipment and the standby equipment.

As described above, in the switching signal generator of the present invention, when the time interval between one alarm signal and the next alarm signal is less than or equal to a certain value, it is recognized as a continuous D alarm signal, and such a mixed alarm signal is A switching signal is generated for the first time when a state in which one device generates a signal and the other device does not generate a signal continues for a certain period of time. Therefore, unlike in the prior art, switching signals are not frequently generated in response to the generation of alarm signals, and furthermore, when both the working equipment and the standby equipment have to issue alarm signals due to a common cause, the working equipment Even if the backup device issues an alarm signal earlier than the backup device, if the backup device also issues an alarm signal within a certain period of time, the backup device will not issue an unnecessary switching signal. In addition, when a failure due to a common cause is resolved, even if the standby equipment stops emitting alarm signals before the working equipment, if the working equipment also stops emitting alarm signals within a certain period of time, it will become useless. No switching signal is issued.

(Example) Hereinafter, embodiments of the invention will be described based on the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a time chart for fully explaining the operation of FIG. 281. Intermittent alarm signals due to the deterioration of the cloth quality as shown in waveforms 16 and 17 in FIG.
A retriggerable multi (ret) is used to shape the waveform so that it will be sent as a continuous a reward signal if the time from when the alarm stops until the θ axis occurs again is within a certain period of time 1d.
riggerble rnulti) circuits 3 and 4
is converted into waveforms 18 and 19 in Figure 2.
2 points, sent to 88 points. At points A2 and B1, the waveforms 18 and 19 are branched into two, and the other one is input to the inverters 6 and 7, respectively, and the other one is input to the exclusive OR circuit 5. It is converted into a signal such as waveform 20, which is output only when there is a difference between the preliminary routes, and sent to point C3. The waveform 2 at point C
of'iz is branched, one directly to the AND circuit 9, and the other input to the reset input terminal of the counter circuit 8 to prevent the output from being sent out unless the difference in alarm signal continues for a certain period of time. 8 is waveform 2 in Figure 2
Outputs a signal indicated by 0'. The output of the counter circuit 8 is again input to the AND circuit 9, and a working/standby differential signal as shown in a waveform 21 is obtained at point C8. At point C1, the waveform 21 is branched into two, and is input to AND circuits 10 and 11 in order to perform AND with the inverters 6 and 7, respectively.
Outputs of waveform 22 and waveform 23 are obtained for outputting a circuit switching signal to the points where the frequency of alarm occurrence is low, respectively. The outputs of the waveforms 22 and 23 are input to the flip-flop circuit constituted by the AND circuit 12 and 13. 15 and are respectively sent to the switching circuits of the transmission lines.

Here, the switching signal output terminal 14 is inputted to the input terminal 1 to the drive circuit of the switch that selects the transmission path of the device that generates the alarm signal, and conversely, the switching signal output terminal 15 is inputted to the input terminal 2. If the transmission path of the device that generates the δ compensation signal is connected to the drive circuit of the switch that selects the transmission path, it is possible to make sure that there is a predetermined difference in the generation status of the report signal in the working and standby, and that the θ compensation signal By selecting the transmission line side in which the occurrence frequency of occurrence is low and the duration is short, stable switching operation can be performed even if intermittent reward signals are input.

(Effects of the Invention) As explained above, in the switching signal generation circuit of the present invention, when the time interval between one official gazette signal and the next alarm signal is less than a certain value, it is considered as one continuous alarm signal. In addition, unless the condition in which the -17jL79 alarm signal is emitted between the active device and the backup device and the other device does not emit an alarm signal continues for a certain period of time, the switchover signal will not occur, so if the active device Even if the UT continuously emits the θ-axis, it will not switch unless the above-mentioned conditions are met, and if the above-mentioned conditions are met, it will switch to the backup device that is not emitting an alarm signal, so it is stable. This has the advantage that the switching operation can be performed in a controlled manner.

In addition, if the current and backup devices both issue alarm signals due to a common cause, even if there is a time difference, or conversely, they recover together, the time difference is within a preset time. This has the advantage that no unnecessary switching operations occur.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a timing waveform diagram illustrating the operation of the switching signal generation circuit according to the present invention. 1.2... Input terminal, 3, 4... Retriggerable multi circuit, 5... Exclusive OR circuit 6, 7.
...Inverter, 8...Counter circuit, 9
...first AND circuit, lO...second AND circuit, 11...third AND circuit, 12.13.
...NAND circuit, 14.15...Output terminal, 16
．． 17... Input alarm signal, 18.19... Output waveform of retriggerable multi circuits 3 and 4, 20.
...Output waveform of exclusive logic circuit 5, 20'...Deba waveform of counter circuit 8, 21...Output waveform of first AND circuit 9, 22...Second AND circuit 1
Output waveform of ゜, Output waveform of the third AND circuit 11 of the 23rd river, 24.25...Output switching signal agent Patent attorney Yahata G-Sen Hiroshi/Fig.

Claims (1)

[Claims] If the next rectangular wave signal appears as an input within a preset time after one input rectangular wave signal ends, the previous rectangular wave signal and the next rectangular wave signal are continuous to form one rectangular wave signal. Two retriggerable multi-circuits (first
a retriggerable multi-circuit and a second retriggerable multi-circuit), and two inverters (a first inverter and a second inverter) that invert the outputs of the two retriggerable multi-circuits, respectively; an exclusive OR circuit that detects a difference between the outputs of the two retriggerable multi-circuits, and a counter that generates a waveform signal that falls at the rising edge of the output waveform of the exclusive OR circuit and rises after a predetermined time has elapsed. , a first AND circuit that takes the logical product of the output signal of the counter and the output signal of the exclusive OR circuit, and the output signal of the first AND circuit and the output signal of the first inverter. a second AND circuit that takes an AND; a third AND circuit that takes an AND of an output signal of the first AND circuit and an output signal of the second inverter; A switching signal consisting of a flip-flop circuit that receives the output signal of the product circuit and the output signal of the third AND circuit and generates a rectangular wave signal that rises when one output signal rises and falls when the other output signal rises. generation circuit.