JPH02276312A - Standard frequency generator - Google Patents

Abstract

PURPOSE:To keep the function of a standard frequency generator without generating the hit of frequency output and lowering reliability by performing parallel redundant operations ordinarily, and operating a remaining oscillator by switching a system to a standby redundant operating system when the parallel operations become infeasible due to the faults of several oscillators. CONSTITUTION:The output of three frequency generators are connected to a switch 103 and a majority decision device 104, and a signal from the switch 103 is bi-sected, and one is connected to an adder 105 and the other to the adder 105 via a subordinate oscillator 106. The frequencies and levels of the output of the three frequency generators are monitored by the majority decision device, and the output of the frequency generator whose output is assumed as most accurate is selected at the switch, and is set as the output of the standard frequency generator via the adder. When the fault occurs in the frequency generator 101a, a power source is applied to the subordinate oscillator 106, and the output of a frequency oscillator 101b is synthesized with that of the subordinate oscillator 106 at the adder 105, then, oscillation output is issued.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a standard frequency generator, and more specifically, in a standard frequency generator that operates three or more units redundantly in parallel, the output is momentarily cut off even if one of them fails. The present invention relates to a standard frequency generator capable of generating accurate signals without reducing reliability.

(Prior Art) Various types of systems have been proposed as highly reliable standard frequency generators, one of which includes three frequency generators 1a, lb, and lc as shown in Figure 2. There is a device configured to monitor the frequency and level of the output by a majority decision device 2, and to selectively output one of the outputs deemed to be the most accurate by controlling a switch 3.

This type of standard frequency generator requires at least three frequency generators, and adopts the signal phase that accounts for the majority in the majority decision device, or the output of the oscillator that is closest to the average value or median value of all. It is a frequency signal.

However, if one of the three devices breaks down, it becomes impossible to make a decision based on a majority decision, and the reliability of the device is significantly reduced.

Generally, when a failure occurs in a frequency generator, a majority decision device detects this and issues an alarm, but the remaining two frequency generators are then driven to generate output.

If the average lifespan of one unit is l/λ, the reliability in this case is 11/6λ when there are three units, which is about twice as long as when there is one unit, whereas when there are two units, it is 3/2λ. This results in a reduction of approximately 1.5 times that when using one unit.

Incidentally, the average lifespan λ of the frequency generator is the average failure rate, which is generally λ(!).

(Object of the Invention) The present invention has been made to eliminate the drawbacks of the conventional wave number generator for general use. The purpose of this invention is to provide a standard frequency generator without momentary interruption of output.

(Summary of the invention) In order to achieve this object, the present invention provides a standard frequency generator that operates three or more frequency generators in parallel and redundantly, when some of them fail and the remaining frequency generators become less than two. The present invention is characterized in that the parallel redundant operation is automatically switched to the standby redundant operation.

(Example) Hereinafter, the present invention will be described in detail based on Examples.

FIG. 1 is a block diagram showing an embodiment of a standard frequency generator according to the present invention, and this example shows a case where three frequency generators are provided.

In FIG. 1, 101a, 1olb, and 1oIC are frequency generators, and the power supplied to these is turned on and off by the power supply control unit 102.

In addition, the outputs of the three frequency generators are connected to a switch 103 and a majority decision unit 104, and the signal from the switch 103 is divided into two, one of which is sent to an adder 105 and the other is a dependent It is connected to the adder 105 via the oscillation H106.

Further, the power supply to the dependent oscillation 8106 is also turned off by the power supply control section 102.

To explain the operation of this configuration, first, in a normal state, there are three frequency generators 101a.

101b and 101c are all equipped with a power supply control unit 102.
is powered through the slave oscillator IQ
The power supply to 5 is cut off, and parallel redundant operation is executed based on the output of this 3° frequency generator.

The operation at this time is the same as the conventional one described above, so a detailed explanation will be omitted, but the outputs of the three frequency generators are monitored by a majority decision device, and the frequency and level are monitored, and the frequency generator deemed to be the most accurate is selected. The output of the standard frequency generator is selected by a switch and passed through an adder as the output of the standard frequency generator.

At this time, since the output of the dependent oscillator is not input to the adder, the output of the adder selected by the switch is output as is.

Next, if it is assumed that the frequency generator 101a selected by the switch among the frequency generators breaks down, the majority decision device immediately detects this and the switch 101a
A switching command signal 107 is output to the frequency generator 101b, and the output of the frequency generator 101b is selected by the switch.

At this time, the remaining frequency generators serve as a stand, making it impossible to make a majority decision, so the dependent oscillator 10
The output from the frequency oscillator ztotb and the output from the dependent oscillator lO6 are combined by an adder 105 to produce an oscillation output.

The frequency generator in this state is generally referred to as a standby redundant system, and the remaining frequency oscillator +01c is on standby as a standby oscillator.

If the frequency oscillation Htoxb further fails in this state, the majority decision unit 104 detects this and the switch 1
03 and thereby select the oscillator 101c.
Make it.

Note that the power to the standby oscillator is normally turned off, so
At the time of switching, the power is turned on by the power supply control section 102, but the oscillation frequency is not stable for a while after the power is turned on to one oscillator, so this output cannot be used immediately.

Therefore, until the switched oscillator becomes stable, the dependent oscillator 1
Let the output of 06 be the output of the frequency generator.

With this configuration, three oscillators can be used in parallel redundant operation and two
By using two oscillators, it is possible to maintain the same reliability as during standby redundant operation, and there is no momentary interruption of output when switching between the two.

In this case, if the average lifespan of an oscillator is I/λ, then II/λ(-
However, when two oscillators are operated redundantly on standby, the reliability becomes 2/λ (twice as much as when one oscillator is used), so the reliability of both is equivalent.

(Effect of the invention) As described above, the present invention normally performs parallel redundant operation,
If some oscillators fail and parallel operation becomes impossible, the remaining oscillators are configured to switch to standby redundant operation mode, so there is no momentary interruption in frequency output and reliability is improved. The functionality of the standard frequency generator can be maintained without any deterioration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional standard frequency generator. la, lb, lc, 101a, 101b, 101C...
...Frequency generator, 3.103...Switcher,
2.104...Majority decision device, +05...Adder, 106...Subordinate oscillator patent applicant Toyo Tsushinki Co., Ltd.

Claims (2)

[Claims] (1) In a standard frequency generator that operates three or more frequency generators redundantly in parallel, if a failure occurs in some of the frequency generators, the remaining frequency generators are configured to operate redundantly in parallel. A standard frequency generator characterized by: (2) In the case where the standard frequency generator is equipped with three sets of frequency generators, it is further equipped with a dependent oscillator,
When one of the frequency generators fails, one of the remaining frequency generators is driven, the dependent oscillator is operated, and the oscillation outputs of both are added to generate an output. A standard frequency generator according to claim (1).