JPH0446024B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an antenna failure detection device that detects failures in antennas and power feeding systems, abnormalities in adjustment conditions, and the like.

[Prior art] In order to detect a failure or abnormality in an antenna or power supply system (hereinafter referred to as an antenna failure), there is a method of measuring the magnitude of the reflected wave of the transmitted signal at the output end of the transmitter and making a determination based on that value. There is.

This is done by performing impedance matching between the antenna and the feeding system at the output end of the transmitter under normal conditions without any antenna failures, and making adjustments so that the reflected signal seen from the transmitter side is sufficiently small.

When an antenna failure occurs, the impedance matching breaks down and as a result, the reflected signal increases.The failure determination circuit detects the change in the signal level, and when the reflected signal exceeds a certain value, the antenna It is determined that a failure has occurred.

As a device for determining antenna failure in this manner, there is an antenna failure detection device as shown in FIG. This will be explained below using FIGS. 7 and 8.

Figure 7 shows a block diagram of the antenna failure detection device.
The reflected signal from the feed system 2 is selectively distributed and outputted by the directional coupler 4 connected between the output end of the transmitter 3 and the feed system 2, and then output to the detector 5.
As shown in FIG. 8, this detected output is compared with a failure detection voltage 28 set in the failure determination circuit 6 to determine whether it is normal or a failure has occurred.

That is, if an antenna failure occurs at time T, vector 21 represents the reflected signal before the antenna failure occurs, vector 22 represents the reflected signal after the antenna failure occurs, and the detected output voltage is equal to signal 2.
7, and this signal 27 is compared with a failure detection voltage 28 in the failure determination circuit 6.

The signal 27 from time 0 to T is the fault detection voltage 28
Since it is lower, no antenna failure has occurred, and at time T, the value becomes higher than the failure detection voltage 28 and it is determined that a failure has occurred.

However, if another transmitter 7 is installed nearby and its transmitted signal is radiated from antenna 8, it will be received by antenna 1 as a received signal indicated by vector 23, and detected via directional coupler 4. The detected output voltage is shown as a signal 29 in FIG. 8b.

Therefore, if there is no failure in antenna 1, the received signal shown by vector 23 is added to the reflected signal (vector 21) at antenna 1, as shown in FIG. 8a, and the received signal is shown by composite vector 24. It becomes a composite signal, and its detection output is shown in Figure 8b.
This is indicated by signal 30.

If a failure occurs in antenna 1 at time T, the received signal (vector 23)
The composite signal added to the reflected signal (vector 22) at
is shown by a vector 25 of the composite signal. The signal of this composite vector 25 is input to the detector 5 via the directional coupler 4 and detected. This detected output voltage becomes a signal 30, as shown in FIG. 8b.

[Problems to be Solved by the Invention] As described above, when another transmitter 7 is installed nearby, unnecessary signals are received by the antenna 1. In this case, even if there is no failure in the antenna 1, the detected output voltage (signal 29) of the detector 5 is the failure detection voltage 28 in the failure determination device 6.
Since it is above the level of , it is mistakenly determined that a failure has occurred. In this way, the transmitter 7 has become a source of unnecessary signals, causing erroneous determinations.

In particular, transmitter 3 and transmitter 7 as an unnecessary signal source.
If both signal frequencies are close to each other, the installation distance between antenna 1 and antenna 8 is short, and the output power of transmitter 7 is large, the unnecessary signal from transmitter 7 will be large and separation will be difficult. Therefore, there was a problem that the influence was significant.

[Means for Solving the Problems] A first invention includes: a signal distributor that distributes unnecessary signals from unnecessary signal sources; a directional coupler that distributes a composite signal including a reflected signal of the unnecessary signals; A phase shifter that inverts the phase of the unnecessary signal, an attenuator that adjusts the level of the phase-inverted unnecessary signal to the same level as the original unnecessary signal, and a combined signal with the phase-inverted unnecessary signal from this attenuator. A signal synthesizer that removes unnecessary signals by vectorially combining them, and a failure determination circuit that detects the reflected signal output from this signal synthesizer and determines a failure. This is designed to accurately detect failures.

A second invention also provides a signal splitter that distributes unnecessary signals from an unnecessary signal source, a directional coupler that distributes a composite signal including the unnecessary signal and a reflected signal, and a composite signal from the directional coupler. a detector that detects the
A detector that detects the unnecessary signal distributed from the signal distributor, a level adjuster that adjusts the detection output of the unnecessary signal from this detector to the same level as the detection output of the unnecessary signal included in the composite signal, and the composite signal. A signal subtracter that subtracts and removes the detection output of an unnecessary signal from the detection output of the signal subtractor, and a failure determination circuit that determines a failure based on the reflected signal output from this signal subtracter,
This method removes unnecessary signals to accurately detect antenna failure.

[Operation] The first invention receives an unnecessary signal from an unnecessary signal source, inverts the phase of the received unnecessary signal using a phase shifter, and then changes its level to that of the original unnecessary signal using an attenuator. Adjust the level to the same level and input it to the signal synthesizer.

On the other hand, a composite signal containing an unnecessary signal and a reflected signal is distributed by a directional coupler and inputted to a signal combiner. In the signal synthesizer, the unnecessary signal from the unnecessary signal source and the composite signal are added vectorially, the unnecessary signal is removed from the composite signal, and only the reflected signal is input to the detector, where it is detected and determined by the failure detector. be done.

In the second aspect of the invention, a composite signal including an unnecessary signal and a reflected signal is distributed by a directional coupler and inputted to a signal synthesizer, which is detected by a detector and inputted to a signal subtracter.

On the other hand, after the unnecessary signal from the unnecessary signal source is detected by the detector, the level of the detected output is adjusted by the level adjuster so that it is at the same level as the detected output of the unnecessary signal in the composite signal, and then the detected output is adjusted by the level adjuster and sent to the signal subtracter. is input.

In the signal subtracter, the detection output of the unnecessary signal is subtracted from the detection output of the composite signal to remove the unnecessary signal, and only the reflected signal is determined to be faulty in the fault determination device.

[Embodiments of the Invention] Example 1 A first embodiment of the present invention will be described in detail based on FIGS. 1 and 2.

FIG. 1 is a block diagram showing an embodiment of the present invention, in which symbols 1 to 8 are the same as those of the conventional example shown in FIG. 7, code vectors 21 to 25 and signal 2.
7 to 30 are the same as those of the conventional example shown in FIG. 8, so their explanation will be omitted.

9 is a signal splitter for extracting a part of the unnecessary signal from the transmitter 7; 10 is a phase shifter for adjusting the phase of the unnecessary signal; 11 is an attenuator for adjusting the level of the unnecessary signal; 12 is a A signal combiner combines the combined signal from the directional coupler 4 and the unnecessary signal from the attenuator 11 vectorwise.

A is a composite signal containing unnecessary signals and reflected signals, B
is an unnecessary signal indicated by a vector 26, and the phase and level of the unnecessary signal have been adjusted.

Next, the operation will be explained.

The composite signal A from the directional coupler 4 is a composite signal of a reflected signal in which a failure occurs in the antenna 1, etc., and an unnecessary signal from the transmitter 7. Vector 2 in Figure 2 a
4, and when a failure occurs in antenna 1 at time T, it is indicated by vector 25.

First, a case where no failure has occurred in the antenna 1 will be described.

In this case, since antenna 1 is in a normal state,
There is almost no reflected signal, which is indicated by vector 21, as shown in FIG. 2a.

Reflected signals (vector 21) from the antenna 1 and feed system 2 that are trying to detect a failure, and unnecessary signals (vector 23) from the transmitter 7 as an unnecessary signal source.
A composite signal (vector 24) of
is input as signal A to

On the other hand, a part of the unnecessary signal from the transmitter 7 as an unnecessary signal source, that is, the signal indicated by the vector 23, is extracted by the signal distributor 9 and input to the phase shifter 10.

In the phase shifter 10, the phase of this unnecessary signal (vector 23) is inverted by 180 degrees, and is input to the attenuator 11, where the level is adjusted to be the same level as the level of the unnecessary signal vector 23. The signal B (vector 26) is input to the signal combiner 12.

In the signal synthesizer 12, the signal A represented by the vector 24 and the signal B represented by the vector 26 are added, and the unnecessary signal vector 23 is removed from the signal A, resulting in a signal represented by the vector 21. Only the reflected signal is inputted to the detector 5, detected, and inputted as a signal 27 to the failure determination device 6, where it is compared with the failure detection voltage 28 and determined that there is no failure.

Next, a case where a failure occurs in the antenna 1 at time T will be described.

In this case, the signal A at the input end of the signal combiner 12 is a reflected signal represented by a vector 22 when there is no unnecessary signal, but since the unnecessary signal from the transmitter 7 is added to this, the signal A is synthesized. The signal is represented by a vector 25, which is obtained by adding vectors 23 and 22 vectorwise.

On the other hand, similarly to the above, a portion of the signal from the transmitter 7 as an unnecessary signal source, that is, the unnecessary signal indicated by the vector 23 is extracted by the signal distributor 9 and input to the phase shifter 10.

In the phase shifter 10, the phase of this received signal (vector 23) is inverted by 180°, and input to the attenuator 11, where the level is adjusted to be the same level as the level of the vector 23, and the signal B ( The signal is input to the signal combiner 12 as a vector 26).

In the signal synthesizer 12, the signal A represented by the vector 25 and the signal B represented by the vector 26 are added vectorially, and the unnecessary signal B (vector 26) is removed from the signal A. Only the reflected signal represented by the vector 22 is input to the detector 5, detected, and input to the failure determiner 6 as a signal 27, where the failure detection voltage 28
It is determined that it is fixed.

In this way, in this embodiment, unnecessary signals are removed vector-wise, so that the influence of unnecessary signals can be completely removed.

Note that the detected output voltage of the vector 25 is the signal 30
The detected output voltage of the unnecessary signal vector 23 is represented by a signal 29.

Embodiment 2 In the first embodiment described above, unnecessary signals can be completely removed, but on the other hand, it is relatively troublesome to adjust the phase and level of the unnecessary signals. Therefore, in the second embodiment, this point is improved.

3 to 4 show a second embodiment of the present invention, and symbols 1 to 9, vectors 21 to 26, and signals 27 to 30 are the same as in the above embodiment and the conventional example, so their explanations are omitted. do.

31 is a detector for detecting the output of the signal distributor 9;
32 is a level adjuster for adjusting the level of the detection output, 33 is a signal subtracter for subtracting signal B' from signal A', signal A' is a composite signal of the reflected signal and unnecessary signal, signal B' is an unnecessary signal, and its detected output voltage is indicated by signal 30.

Next, the operation will be explained.

First, a case where no failure has occurred in the antenna 1 will be described.

A composite signal (vector 24) of reflected signals from the antenna 1 and feeding system 2 that are attempting to detect a failure, and unnecessary signals from the transmitter 7 as an unnecessary signal source.
is selectively outputted by the directional coupler 4 connected between the output end of the transmitter 3 and the power supply system 2 and detected by the detector 5, and the detected output voltage shown by the signal 30 is: Signal to signal subtractor 33
Inputted as A′.

On the other hand, a part of the unnecessary signal from the transmitter 7 as an unnecessary signal source is extracted by the signal distributor 9, detected by the detector 31, and input to the level adjuster 32.

In the level adjuster 32, the level is adjusted so that it becomes the same level as the level of the unnecessary signal included in the signal A' (signal 29 of the detection output voltage), and is inputted to the signal subtracter 33 as the signal B'. .

In the signal subtractor 33, the detection output voltage signal 29 is subtracted from the detection output voltage signal 30, unnecessary signals are removed, and a signal 41 containing only the reflected signal is output, which is input to the failure determination device 6, where it is determined that there is a failure. It is compared with the detection voltage 28 and determined that there is no failure.

Next, a case where a failure occurs in the antenna 1 at time T will be described.

In this case, the detection output voltage of signal B' is
On the other hand, the composite signal A′ is the signal 3
Represented by 0.

In the signal subtracter 33, the signal
B′ is subtracted, and the signal 41 is only the reflected signal.
The fault detection voltage 2 is input to the fault determination device 6.
8 and is determined to be a failure.

In the case of this embodiment, depending on the phase of the unnecessary signal, it may not be possible to completely remove the unnecessary signal. In this case, a phase shifter is connected to the output side of the transmitter 3. It is only necessary to shift the phase of the reflected signal.

Embodiment 3 Next, as shown in FIGS. 5 and 6, the antenna failure detection device described in Embodiment 2 is applied to an SSB Doppler system.
We will explain the application to VOR (Very High Frequency Omnidirectional Radio Beacon).

SSB-type Doppler VOR provides aircraft heading information, and we will explain its application to failure detection of sideband antennas and their power supply systems.

51 has a radius of approximately
50 sideband antenna arrays are arranged at equal intervals on a 6.5m circumference, and 52 is a distributor for sequentially switching and feeding power to the sideband antenna array 51 at time intervals of 1/1500th of a second. It is. 53 is a sideband transmitter, which sets the carrier frequency of the carrier transmitter 54 to f ₀
Then, the frequency is adjusted to f ₀ +9960Hz.

Note that the carrier signal is level modulated at 30Hz.

At the output end of the sideband transmitter 53, impedance matching is achieved in a normal state of the sideband antenna array 51, its feeder line, and the feeder system including the distributor 52, and the reflected signal is small.

However, in Doppler VOR, the carrier antenna 55 is located at the center of the sideband antenna array 51 at a distance of approximately 6.5 m.
The carrier antenna 55 outputs a carrier signal with a transmission power approximately 10 times that of the sideband signal output.

For this reason, the sideband antenna array 51 operates as a receiving antenna for the carrier signal output, and this received signal is superimposed on the reflected signal caused by the original antenna failure etc. and detected, making it impossible to make a normal failure determination. .

Therefore, the carrier wave transmitter 54 is set as the unnecessary signal source in the antenna failure detection device described in the second embodiment of the present invention, and the sideband transmitter 53 is set as the transmitter on the antenna side where the failure is to be determined.

Here, in FIG. 6, a signal 61 is a detection output signal based on a reflected signal from a feeding system including a sideband antenna array 51 and a distributor 52. For example, if the 15th sideband antenna or its This shows a case where a failure occurs in the power supply system. The signal 62 is a reference failure detection voltage set in the failure determiner 6.

However, since the Doppler VOR has a carrier signal level-modulated at 30 Hz, if the received detection signal of the sideband antenna based on this signal is signal 63, the actual output signal of the detector 5 has the waveform shown by signal 64, Accurate failure determination cannot be made.

Therefore, as described in FIG. 3, the signal subtracter 33 is connected to the output terminal of the detector 5, and the signal
A′, i.e. from directional coupler 4 to sideband transmitter 5
3 and a part of the unnecessary signal (carrier wave signal) from the carrier wave transmitter as an unnecessary signal are detected by the detector 5 and inputted to the signal subtracter 33 as the detected signal output signal A'.

On the other hand, a part of the carrier wave signal is taken out from the carrier wave transmitter 54 by the signal distributor 9, and a part of the carrier wave signal is extracted from the carrier wave transmitter 54,
The signal is detected by the level adjuster 32, the level is adjusted to be equal to the signal 63, and the signal is inputted as the signal B' to the signal subtracter 33. The signal B' is subtracted from the signal A' to obtain a signal almost similar to the signal 61. The voltage is determined and compared with the failure detection voltage 62 in the failure determination unit 6 to determine failure.

In addition, in such a Doppler VOR sideband antenna failure detection device, the time difference can be determined by comparing the failure occurrence position determined by the signal 61 and the position of the switching timing clock of the No. 1 antenna of the distributor 52 as shown by the signal 65. Calculate t, and calculate ( ₅₀ ×t÷
The number of the antenna or its feeding system can be accurately determined from the formula t ₀ +1). Therefore, countermeasures against failure occurrence become easier.

Although the second embodiment has been described for antenna failure detection in the SSB Doppler VOR, it goes without saying that similar effects can be obtained by applying the antenna failure detection device of the first embodiment. In addition, there is another Doppler VOR that operates on the same principle as the SSB method, but has two upper and lower sideband transmitters.
Similar effects can be obtained even when this method is applied.

[Effects of the Invention] The first invention includes a signal distributor that distributes unnecessary signals from an unnecessary signal source, a directional coupler that distributes a composite signal including the unnecessary signal and a reflected signal, and a directional coupler that distributes the unnecessary signal from the unnecessary signal source. A phase shifter that inverts the phase, an attenuator that adjusts the level of the phase-inverted unnecessary signal to the same level as the original unnecessary signal, and a vectorial method that adjusts the phase-inverted unnecessary signal from this attenuator and the composite signal. The antenna failure detection device is composed of a signal combiner that combines and removes unnecessary signals, and a failure determination circuit that detects the reflected signal output from this signal combiner and determines the failure, so that unnecessary signal sources located nearby can be detected. Since it is possible to completely eliminate the influence of unnecessary signals other than the reflected signals from the sensor, accurate failure determination can be made.

Furthermore, a second invention includes a signal distributor that distributes an unnecessary signal from an unnecessary signal source, a directional coupler that distributes a composite signal containing the unnecessary signal and the reflected signal,
A detector that detects the composite signal from this directional coupler, a detector that detects the unnecessary signal distributed from the signal splitter, and an unnecessary signal included in the composite signal that detects the detection output of the unnecessary signal from this detector. A level adjuster that adjusts the detection output to the same level as the detection output of the synthesized signal, a signal subtracter that subtracts and removes the detection output of the unnecessary signal from the detection output of the composite signal, and a failure determination that determines a failure based on the reflected signal output from this signal subtractor. Since the antenna failure detection device is constructed with the circuit, it is possible to reduce the influence of unnecessary signals, and since the detected output is used, it has the advantage of being easier to handle than when performing detection at a high frequency stage.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the first embodiment of the present invention, FIGS. 2a and 2b are signal vector diagrams and detection output voltage signal waveform diagrams for explaining the operation, respectively, and FIG. 3 is a block diagram showing the first embodiment of the present invention. FIG. 4 is a block diagram showing the detection output voltage signal waveform for explaining the operation of FIG. 3, FIG. 5 is a block diagram showing the third embodiment, and FIG. 6 is a diagram showing the operation. FIG. 7 is a block diagram showing a conventional example, and FIGS. 8a and 8b are a signal vector diagram and a detected output voltage signal waveform diagram for explaining the conventional example. 1... Antenna, 2... Feeding system, 3... Transmitter, 4... Directional coupler, 5... Detector, 6...
Failure determiner, 7... Unnecessary signal source, 9... Signal distributor, 10... Phase shifter, 11... Attenuator, 12...
Signal synthesizer, 31...detector, 32...level adjuster, 33...signal subtractor.

Claims (1)

[Scope of Claims] 1. An antenna failure detection device that detects a failure of an antenna and its feeding system or an abnormality in its adjustment state based on the magnitude of a reflected signal, comprising: a signal distributor that distributes unnecessary signals from unnecessary signal sources; a directional coupler for distributing a composite signal including an unnecessary signal and the reflected signal; a phase shifter for inverting the phase of the unnecessary signal; an attenuator that adjusts to the same level as the level; a signal synthesizer that vectorially combines the phase-inverted unnecessary signal from the attenuator and the composite signal to remove the unnecessary signal; An antenna failure detection device comprising: a failure determination circuit that detects the output reflected signal to determine a failure, and removes the unnecessary signal from the composite signal to obtain the reflected signal for failure determination. 2. An antenna failure detection device that detects a failure or an abnormality in the adjustment state of an antenna and its feeding system based on the magnitude of a reflected signal, comprising: a signal distributor that distributes an unnecessary signal from an unnecessary signal source; and a signal distributor that distributes an unnecessary signal from an unnecessary signal source; a directional coupler that distributes a composite signal including a directional coupler; a detector that detects the composite signal from the directional coupler; a detector that detects the unnecessary signal distributed from the signal distributor; a level adjuster that adjusts the detection output of the unnecessary signal from the detector to the same level as the detection output of the unnecessary signal included in the composite signal; and a level adjuster that subtracts the detection output of the unnecessary signal from the detection output of the composite signal. , a signal subtracter for removing the signal, and a failure determination circuit for determining a failure based on the reflected signal output from the signal subtracter, and removing the unnecessary signal from the composite signal to obtain the reflected signal for determining a failure. An antenna failure detection device characterized by: