JPH02272917A - Reception circuit switching system - Google Patents

Abstract

PURPOSE:To prevent interruption from being generated in received data when a living reception circuit is made abnormal and switched to an auxiliary reception circuit by delaying a data input time to a selector for more than a time until a selector switching time from the abnormality detecting time of an abnormality detection circuit. CONSTITUTION:In a reception side device 1, living and auxiliary reception circuits 4 and 5 to receive data (a) sent from a transmission circuit 3 of a transmission side device 2, delay buffers 6 and 7, selector 8 and abnormality detection circuit 9 are provided. The delay buffers 6 and 7 respectively delay the data input time form the reception circuits 4 and 5 to the selector 8 for more than the time until the switching time of the selector 8 from the abnormality detecting time of the abnormality circuit 9. Thus, when the reception circuits 4 and 5 are switched, the interruption is prevented from being generated in the data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a receiving circuit switching system for switching to a backup receiving circuit when a working receiving circuit is abnormal.

[Prior Art] Generally, in digital communication, as shown in FIG. 3, the receiving device 21 is equipped with a working receiving circuit 22 and a backup receiving circuit 23, thereby duplicating the receiving circuit and switching the transmitting side. A system is adopted in which data from the transmitting circuit 25 of the device 24 is reliably received.

As shown in the figure, in the conventional receiving circuit switching system, during normal operation, data from the transmitting circuit 25 is received by the receiving circuits 22 and 23, and only the data received by the receiving circuit 22 is sent to the selector 26.
When there is an abnormality in the receiving circuit 22, the abnormality is detected by the abnormality detection circuit 28, and the selector 26 is switched to select only the data from the receiving circuit 23.

[Problem to be solved by the invention]

The conventional receiving circuit switching method described above has the following drawbacks.

As shown in FIG. 4(a), if an abnormality occurs at time t1 and the receiving circuit 22 is unable to receive data from the eighth frame onward, the abnormality detection circuit 28
Detects the second abnormality.

However, since the abnormality detection circuit 28 has the characteristic of switching the selector 26 using abnormality detection as a trigger, it takes T time from the occurrence of an abnormality until the selector 26 is switched, as shown in FIG. 4(b).

By the way, the receiving circuits 22 and 23 are shown in FIG. 4(C).

Data as shown in (d) is input, and selector 2
Assuming that it takes T time to switch 6, Fig. 4(e)
As shown in , the selector 26 selects the data (
(up to the 7th frame) 1. t after T hours.
After 2 o'clock, data from the 12th frame onward of the receiving circuit 23 is selected.

As a result, data from the output terminal 27 is cut off for T time.

The purpose of this invention is to solve the above-mentioned conventional problems.
An object of the present invention is to provide a receiving circuit switching method that does not cause data interruption when switching receiving circuits.

[Means to solve the problem]

This invention includes a working receiving circuit and a backup receiving circuit that receive communication data, a selector that selects output data of the working receiving circuit or the backup receiving circuit, and a selector that detects an abnormality in the working receiving circuit and connects the selector to the backup receiving circuit. an abnormality detection circuit that switches to an output data selection state from the selector; The present invention is characterized in that a delay buffer is provided for delaying the detection of an abnormality in the circuit by a time equal to or longer than the selector switching time ratio.

〔Example〕

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

FIG. 1 is a block diagram showing a receiving circuit switching system according to an embodiment of the present invention.

According to the figure, the receiving device 1 includes receiving circuits 4 and 5 that receive data a sent from the transmitting circuit 3 of the transmitting device 2, delay buffers 6 and 7, a selector 8, and an abnormality detection circuit. 9 is provided.

The receiving circuit 4 is a currently used receiving circuit. This receiving circuit 4
is the delay buffer 6 with received data a as data b.
It has a function of outputting an abnormality signal f to the abnormality detection circuit 9 when an abnormality occurs. On the other hand, the receiving circuit 5
This is a backup receiving circuit. This receiving circuit 5 has a function of outputting the received data a as data C to the delay buffer 7.

The delay buffer 6 has a function of outputting data d obtained by delaying the data b from the receiving circuit 4 by a predetermined time T (>T) to the selector 8. On the other hand, the delay buffer 7 has a function of outputting the data C from the receiving circuit 5 by the delay time T and the data e delayed by the waiting time to the selector 8.

The selector 8 selects the output data d and e of the delay buffers 6 and 7.
It has a function of inputting data, selecting one of the data, and outputting it to the output terminal 10 as data h.

The abnormality detection circuit 9 has a function of sending a switching signal g to the selector 8 to switch the selection state of the selector 8 when an abnormality signal f from the working receiving circuit 4 is detected. Specifically, a switching signal g for selecting data e is sent out when an abnormal signal f is detected, and a switching signal g is sent out for selecting data d when an abnormal signal f is not detected.

Next, the switching operation of this embodiment will be explained.

Data a is sent from the transmitting circuit 3 of the transmitting device 2 to the receiving device 1.
sent towards.

In the receiving device 1, data a is received by receiving circuits 4 and 5, and data b and c are output from each receiving circuit 4.about.5.

Data b and c from the receiving circuit 4.5 are input to a delay buffer 6.7 and output to the selector 8 as data d and e. At this time, data d and e are stored in the delay buffer 6.7.
Due to the action of , the signal is output with a delay of time T1 from the time of input. That is, as shown in FIGS. 2(C) and (d),
From t0 to T during input.

It is output after 1:00, which is delayed by an amount of time.

When the receiving circuit 4 is normal, the receiving circuit 4 does not send the abnormal signal f to the abnormality detection circuit 9, so the abnormality detection circuit 9 sends a switching signal g for selecting data d to the selector 8. Continue to do so.

If the receiving circuit 4 has a fault at 8 o'clock and no longer outputs the data b from the 8th frame onwards, as shown in FIG. A switching signal g for selecting data e based on
is sent to the selector 8. This switching signal g is shown in Fig. 2 (
As shown in b), since the data is input to the selector 8 at 3 o'clock even after T time has elapsed since the failure occurred, the selector 8 selects data e and outputs it as data h after t1 o'clock. By the way, as shown in Fig. 2 (C) and (d), the data d and e are input to the selector 8 from 1 o'clock with a delay of T1 time, so the data is not input from 1 o'clock to -13 o'clock. The 0th to 6th frames of data d are output from the selector 8, and the 7th and subsequent frames of data e are output from the selector 8 after time t3. As a result, as shown in FIG. 2(e), the data h from the selector 8 becomes continuous data from the 0th frame without any interruption.

〔Effect of the invention〕

As explained above, the receiving circuit switching method of the present invention is
A delay buffer is provided on each output side of the working receiving circuit and the backup receiving circuit to delay the data input time to the selector beyond the time from when the abnormality detection circuit detects an abnormality until the selector switching time. When switching to the backup receiving circuit in the event of an abnormality, there is no interruption in received data.

As a result, there is an effect that the receiving side device can always maintain a normal receiving state.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a receiving circuit switching method according to an embodiment of the present invention, FIG. 2 is a time chart showing received data at the time of receiving circuit switching in the receiving circuit switching method of FIG. 1, and FIG. 4 is a block diagram showing a conventional receiving circuit switching method, and FIG. 4 is a time chart showing received data at the time of receiving circuit switching in the receiving circuit switching method of FIG. 3. 4.5...Reception circuit 6.7...Delay buffer 8...Selector 9...Abnormality detection circuit

Claims (1)

[Claims] (1) A working receiving circuit and a standby receiving circuit that receive communication data, a selector that selects the output data of the working receiving circuit or the standby receiving circuit, and a selector that detects an abnormality in the working receiving circuit and switches the selector from the standby receiving circuit. and an abnormality detection circuit that switches to an output data selection state, the receiving circuit switching system comprising: an abnormality detection circuit that switches to an output data selection state, wherein each output side of the working reception circuit and the backup reception circuit has a data input time to the selector determined by the abnormality detection circuit. A receiving circuit switching system characterized in that a delay buffer is provided for delaying the time from the time of abnormality detection to the selector switching time or more.