JPH0317268Y2 - - Google Patents

Description

[Detailed description of the invention] 1. This is caused by the switching of the received signal obtained by receiving radio waves while alternately and continuously switching each of the doublet antennas of an antenna pair having two spaced doublet antennas. Signal that detects the phase difference (hereinafter referred to as direction detection signal)
and an audible signal that detects the communication content of the radio waves, and detects the direction of arrival based on a change in the direction detection signal when the antenna pair and direction are changed with respect to the direction of arrival of the radio waves. A direction finding device comprising: a. a DC signal whose DC value changes in response to a change in the amplitude of the orientation detection signal based on the orientation detection signal (hereinafter referred to as a detected DC signal);
b) frequency changing means for obtaining an audible low frequency signal whose frequency changes in response to a change in the DC value based on the detected DC signal; c) audible sound due to the audible signal and the audible low frequency 1. A device comprising: listening to a signal; and listening means for listening to a signal.

2. The device according to claim 1, wherein the frequency changing means includes a voltage frequency conversion circuit for converting the detected DC signal into the audible low frequency signal.

3. Utility model registration The device according to claim 1, wherein the listening means includes a switching circuit for switching to output the audible signal and the audible low frequency signal individually or in a mixture. Something to do.

4 Utility Model Registration The device according to claim 1, wherein the DC detection means obtains the detected DC signal based on a signal corresponding to one of the positive and negative polarities of the amplitude of the direction detection signal. Something that is equipped with.

〓Field of Industrial Application〓 The present invention relates to a direction finding device that detects the arrival direction of radio waves based on a detection signal of a phase difference caused by switching in a received signal obtained by switching and connecting two antennas.

〓Prior art〓 This type of direction finding device detects a direction in response to a change in the direction of arrival of radio waves by detecting a phase change at the time of signal switching, which is obtained by alternately switching two spaced apart antennas. A configuration in which a signal is obtained and displayed on a cathode ray tube or the like (hereinafter referred to as the first conventional configuration) is disclosed in Japanese Patent Publication No. 23-734 and others.

In addition, the detection signal of the phase difference at the switching point in the received signal obtained by alternately and continuously switching and connecting each antenna of an antenna pair having two antennas arranged at intervals is detected as a positive and negative signal corresponding to each antenna switching direction. The system detects bipolar signals and supplies them to a meter that indicates both positive and negative polarities to display them, thereby making it possible to determine whether the antenna pair is in the positive or negative direction corresponding to the arrival direction of the radio waves and to monitor the direction deviation. The configuration (hereinafter referred to as the second conventional configuration) is disclosed in Japanese Patent Application No. 59-263198 (Japanese Unexamined Patent Publication No. 59-263198) filed by the applicant.
61-139770).

In addition, an adkotoku antenna or loop
Rotate the antenna and reception instruction part as one,
A configuration (hereinafter referred to as the third conventional configuration) that detects the arrival direction of radio waves by changing the amplitude of the received signal using a so-called figure-eight directional characteristic to change the audibility of the communication content of the radio waves, Jitsukai Showa 56-
119583, Utility Model Application Publication No. 56-121178, etc.

〓Problems to be solved by the invention〓 Among the above conventional technologies, in the first conventional configuration, the phase change must be visually monitored, so the display surface of the cathode ray tube or the like must be constantly monitored during use. In addition, even in the second conventional configuration, since the direction is indicated by a meter with positive and negative polarities, this meter must be constantly monitored during use. There is an inconvenience.

In the third conventional configuration, the directivity of the antenna itself has a so-called figure-eight characteristic, so when the antenna is rotated, the amplitude of the received signal changes, and the audible sound changes depending on the direction in which the radio waves arrive. Therefore, there is an advantage that direction can be measured by listening to sound.

However, it is known that this type of antenna cannot be used well for direction finding due to the characteristics of the antenna configuration when the radio wave frequency reaches high frequencies such as VHF or UHF.

In such cases, it may be effective to use a method of sequentially switching multiple spaced antennas and detecting the phase difference in the received signal caused by this switching to determine the bearing, that is, a pseudo-Doppler method. Are known.

However, in the case of this pseudo-Doppler type,
Even if the antenna is rotated, the amplitude of the received signal does not change as in the third conventional configuration described above, so measurement by hearing cannot be performed.

For this reason, it is possible to use a local oscillator to listen to the sound using a so-called beat, as in the conventional silent direction finding device, but this method has the disadvantage that a sense of direction cannot be obtained by listening to the beat alone. be.

Therefore, there is a problem in that it is desired to provide something that does not have these inconveniences.

〓Means for Solving the Problem〓 The present invention is obtained by receiving radio waves while alternately and continuously switching between an antenna pair having two doublet antennas spaced apart as described above and each doublet antenna. A signal that detects the phase difference caused by switching the received signal, that is, a direction detection signal, and an audible signal that detects the content of radio wave communication are obtained, and the direction of the antenna pair is changed with respect to the direction of arrival of the radio wave. In a direction finding device that can detect the direction of arrival of radio waves based on changes in the direction detection signal when ,
That is, a DC detecting means for obtaining a detected DC signal, a frequency changing means for obtaining an audible low frequency signal whose frequency changes in accordance with the change in the DC value based on the detected DC signal, and an audible sound using the audible signal. The above-mentioned problem can be solved by providing a listening means for listening to a sound using the above-mentioned audible low-frequency signal.

〓Example〓 Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of the external appearance of the device when it is naked, FIG. 2 is a block diagram of the electric circuit, and FIGS. 3 and 4 show the signal waveforms and operating characteristics of the main parts. First, to explain the configuration of the electric circuit, in FIG. 2, the doublet antenna 1A,
1B has two doublet antennas with broadband frequency characteristics arranged at intervals, each output of which is guided to the switching scanning circuit 2, and the switching scanning circuit 2 is controlled by the switching signals a and b given from the switching wave circuit 3. The diode switching circuit of 1A and 1B is alternately and continuously switched by ON-OFF operation to create a switching detection signal c, that is, a reception signal, in which the outputs of the doublet antennas 1A and 1B are alternately arranged, and is applied to the selective amplification circuit 4 via the attenuation circuit 16,
After selecting only the frequency of the target radio wave and amplifying it to the required signal strength and form, the selected amplified signal c1 is used by the direction detection circuit 5 to detect the amount of phase change at each switching point in this signal c1. Phase detection is performed to generate a direction detection signal d.

The detected value of the direction detection signal d is maximum when the direction of arrival of the radio wave is on the extension of the line connecting doublet antennas 1A and 1B, and minimum when it is perpendicular to this, and whether the direction of arrival is forward or backward. Therefore, the polarity of the signal is determined in the same manner as in well-known phase detection, and the amplitude is output with a positive polarity, as shown in signal d in Fig. 3, or the amplitude is output with a negative polarity. Become.

a frequency corresponding to the switching period of switching signals a and b;
For example, a bandpass filter circuit with a center frequency of 2KHz
The BPF 6 generates an azimuth component signal e having an alternating current component consisting of the fundamental wave component from the azimuth detection signal d, and the delay circuit 7 converts the zero cross point y of this signal e to the switching signals a and b. A delayed signal f is generated to match the starting edge point.

The synchronous wave rectifying circuit 8 is a circuit that outputs one specified signal section of the switching signals a and b with the same polarity and inverts the polarity of the other signal section, such as an amplifier circuit and an analog switch. This is a combination circuit with a switching circuit such as a switch, and in the example shown in Fig. 3, the section of the switching signal a is set to the inverted side, and the delayed signal f is set to the side promised to switch and scan the doublet antennas 1A and 1B. A rectified signal g is generated by rectifying the wave to match the signal polarity of the section. Therefore,
This rectified signal g becomes a pulsating waveform signal with an amplitude of polarity that has a certain agreement with the arrival direction of the radio wave.

A DC signal h obtained by smoothing the rectified signal g by a smoothing circuit 9 is applied to a voltage frequency conversion (V/F conversion) circuit 10 to generate an audible low frequency whose frequency changes in accordance with the value of the DC signal h. Convert to signal and generate direction sound signal k
make. An example of the operating characteristics of this V/F conversion circuit 10 is shown in FIG.

A sound switching circuit 11 and a sound output circuit 1 are used to mix the direction sound signal k with the audio sound signal m described later.
2, the signal is outputted by the earphone 13 as a sound for aurally determining the direction of arrival of the radio wave.

On the other hand, the communication content in the radio wave is detected by the voice detection circuit 14 from the selective amplification signal c1, and the notch filter circuit 15 is used to remove the switching scanning noise signal caused by the switching signals a and b contained in this detection signal. , the switching frequency Fc of the switching signals a and b is removed to generate the audio signal m.

For this reason, the switching frequency Fc is selected to be a frequency that has relatively little influence on voice hearing sensitivity, for example, 2 KHz or more or 100 Hz or less.

The audio signal m is transmitted through the sound switching circuit 11 and the sound output circuit 12.
The signal is output to the earphone 13 via the .

The sound switching circuit 11 performs switching between outputting the azimuth sound signal k and the audio signal m, either singly or as a mixture.

Also, the DC voltage n obtained by the smoothing circuit 9
By giving this to the meter 21, the arrival direction of the radio wave can be visually known from the maximum or minimum point. Since this direction finding device is mainly used in a location close to a radio wave transmission source, the amplification degree adjustment of the selective amplification circuit 4 relies only on AGC (automatic gain control), and the apparent receiving sensitivity of the device The adjustment is performed by adjusting the degree of attenuation of an attenuation circuit 16 provided on the input side and having a variable attenuation function. Also, when the frequency of the detection radio wave is high, the Doppler shift amount is large, and when it is low, it is small, and the detected value of the direction detection circuit 5 changes accordingly, and the direction detection sensitivity changes, so this change can be In order to make the adjustment, a detection adjustment circuit 24 is provided which varies the amplification degree of a circuit for amplifying the direction detection signal d attached to the direction detection circuit 5 in inverse proportion to the value of the reception frequency signal r set in the selection amplification circuit 4. The output value of the direction detection signal d is automatically adjusted to be within a fixed value range.

The circuit configured as described above, excluding the doublet antennas 1A and 1B and their output parts, is housed in the cabinet 105 as a reception indicator section, and the first
As shown in the figure, it is placed between two spaced apart doublet antennas 1A and 1B. Also,
A sensitivity adjustment operation device 17 for varying the degree of attenuation of the attenuation circuit 16, a sound adjustment operation device 18 for varying the output volume of the sound output circuit 12, an earphone connector (or jack) 19, and a sound switching circuit 11.
A sound selection operation device 20 for selecting and switching operations, and a meter 2 for visually determining direction.
1 is provided on the upper outer wall portion 23, and a selection operation device 22 for selectively operating the receiving selection frequency of the selective amplification circuit 4 is arranged so as to be provided on the side outer wall portion on the side not facing the doublet antennas 1A and 1B. be.

Doublet antennas 1A and 1B are antenna conductors 1A1, 1A2 and 1B1, 1B2 in which two conductor plates of isosceles triangular or similar shape are arranged one above the other with their apex angles facing each other.
As a result, these are sent to the cabinet 10 of the reception instruction section.
Insulating arms 103A protruding from both opposing sides of 5
Insulating plates 101A and 1 fixedly supported in parallel by 1,103A and 103B1, 103B2
It is attached and formed on the front or back surface of 01B. Antenna output take-out transformers 102A and 102B (for example, baluns) are provided at opposing points of each of the apex angles, and take-out cables 104A and 102B are provided thereto.
Connect each one end of 4B and connect the other end to the cabinet 10.
5 and is arranged so as to lead to the switching scanning circuit 2 in the cabinet 105. In addition, insulating arms 103A1, 103A2, 103B
1,103B2 and insulating plates 101A, 101B
are made of, for example, an FRP resin material, and the antenna conductors 1A1, 1A2 and 1B1, 1B2 can be made, for example, by patterning an insulating material plate with a thin copper plate layer for a printed wiring board by photoetching or the like.

In addition, insulating plates 101A and 101B of the antenna part
The height Hz of the receiver is set to be equal to or smaller than the height _H1 of the cabinet 105 of the reception instruction section so that the mechanical upper and lower holding levels are performed by the bottom and top surfaces of the cabinet 105. A battery for operating power is housed within the cabinet 105.

The device configured as shown in FIG. 1 is equipped with a carrying handle 201 on the top outer wall 23 as shown in FIG. While listening, move your hands or body to rotate the entire device and find the point of maximum change in tone. It is possible to detect that there is a source of radio waves. However, these direction finding devices are often used primarily to detect the source of illegal radio waves without the other party knowing, so they are used in camouflage by changing their appearance.

In other words, as shown in Fig. 6, a portable trunk 2 made of an insulating material such as a leather attaché case
The device shown in FIG. 1 is housed inside the upper outer wall 2.
Each operating device necessary for azimuth judgment in step 3, e.g. 17~
An operating hole 202A and a cover 202B are provided on the upper surface of the trunk 202 corresponding to a portion 21. Moreover, if necessary, a notch hole 202C for the cord of the earphone 13 is provided. At a point far from the source of the detection radio waves, buckle stopper 2 of the trunk 202.
02F, open the trunk lid 202G, operate the selection controller 22, etc. to select the frequency, radio wave format, etc.
The cover 202B on the 02H side is opened to operate the operating devices necessary for direction judgment, and at a point near the source, the trunk cover 202G is kept closed and only the cover 202B is opened to operate the control devices necessary for direction judgment. Increase camouflage by operating and using only the same type of equipment.

〓Transformation〓 This invention can be implemented in the following modifications.

(a) Since it is portable, it is necessary to make the structure as compact as possible; however, in low frequency bands, the doublet antennas 1A and 1B are small and may have insufficient sensitivity. In this case, this problem can be solved without increasing the external size of the device by modifying the doublet antennas 1A and 1B as follows. As shown by chain lines in FIG. 5, conductor plates 1A1, 1A2 for doublet antennas 1A, 1B
And at each outer end of 1B1 and 1B2, there is a conductor plate 1 bent in an L shape toward the cabinet side of the reception instruction section.
11A1, 111A2 and 111B1, 11
1B2 as the top mounting body of each antenna, double antennas 1A,
The effective length is increased by lowering the substantial resonance frequency of 1B.

(b) support arms 103A1, 103A2 and 1 to strengthen the support strength of the antenna portion of the device;
03B1 and 103B2 are each made into multiple pieces.

(c) A speaker operated by the output of the sound output circuit 12 is provided on the upper outer wall portion 23 of the reception instruction section, and a circuit is provided to switch between this and the earphone connector 19, so that the earphone 13 is not used.
It camouflages the user's appearance as if he is simply carrying a bag, etc., and allows the direction to be determined based on the sound of the speaker.

(d) Doublet antenna conductor plate 1A1, 1A
2, 1B1, and 1B2 can be modified into a pentagonal shape, rectangular shape, etc. according to the desired broadband property.

(e) The synchronous wave number circuit 8 is configured to select and output only one specified signal section, for example, the section of the switching signal a, and not output the other sections, so that the waveform of the signal g is output every other section. The circuit may be modified to obtain a pulsating flow that is output to the circuit. In this case, the direction finding sensitivity will be somewhat reduced.

(f) The detection adjustment circuit 24 may not be operated with variable amplification in inverse proportion to the receiving frequency, but may be modified into a form in which it is divided into several stages with an appropriate frequency range, and this variable amplification The target for which the direction detection signal d is obtained also receives the DC signal h from the circuit that obtains the direction detection signal d.
Then, the process may be performed by selecting an appropriate location in the circuit until the DC voltage n is obtained. Furthermore, the variable amplification adjustment for this detection adjustment does not operate automatically in conjunction with the selection of the reception frequency, but may be configured to be manually switched and selected in parallel with the operation of the selection operator 22. good.

[Effect of idea]

According to the present invention, as described above, based on the direction detection signal d, the direction detection signal d
A DC signal h whose DC value changes in response to changes in the DC value is detected and obtained, and an audible low-frequency signal whose frequency changes in response to changes in the DC value is obtained as an azimuth sound signal k using the detected DC signal h. At the same time, the audio detection circuit 14 detects the content of the radio wave communication and obtains the audio signal as the audio signal m, and the configuration is such that the audio signal m and the direction signal k are heard. If the pairing direction of the two antennas 1A and 1B, that is, the direction of the line connecting the antennas 1A and 1B, changes with respect to the direction of arrival of the radio waves, the frequency of the direction sound signal k changes. As shown in the figure, the pitch of the sound changes so that the predetermined antenna switching side has the highest frequency or the lowest frequency and is heard, so the measurer can get a sense of direction based on the pitch.

Furthermore, the sound switching circuit 11 allows the audio signal m for listening to the communication content and the azimuth sound signal k to be heard in a mixed manner, making it possible to search.

[Brief explanation of drawings]

The drawings show an embodiment. Fig. 1 is a structural perspective view of the device in a bare state, Fig. 2 is a block diagram of the circuit configuration, Fig. 3 is a signal waveform diagram of each part, and Fig. 4 is an operational characteristic diagram of the main circuit. , FIGS. 5 and 6 are perspective views of the usage mode. 1A, 1B...Double antenna, 2...Switching scanning circuit, 3...Switching wave circuit, 4...Selection amplifier circuit, 5...Direction detection circuit, 6...Band filter circuit, 7...Delay circuit, 8...Synchronous rectifier circuit, 9...
...Smoothing circuit, 10...V/F conversion circuit, 11...
Sound switching circuit, 12... Sound output circuit, 13... Earphone, 14... Audio detection circuit, 15... Notch filter circuit, 16... Attenuation circuit, 17... Sensitivity adjustment operator, 18... Sound adjustment operator , 19... Connector, 20... Sound selection operator, 21... Meter, 24... Detection adjustment circuit.