JPH0843465A - Radio-wave monitoring apparatus - Google Patents

Abstract

PURPOSE:To obtain a radio-wave monitoring apparatus by which radio waves within a prescribed frequency range are monitored simultaneously in real time. CONSTITUTION:A plurality of band-pass filters 16 are constituted in such a way that their passing frequencies are different from each other, and they respectively receive an output signal from an antenna 10 which receives radio waves. Judgment means 20 compare output levels from the plurality of band-pass filters with a judgment criterion level from a control means 26 so as to monitor the radio waves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for monitoring illegal radio waves in real time.

[0002]

2. Description of the Related Art In order to use radio waves effectively and systematically, it is necessary to use each wireless device under a predetermined condition. However, there is a possibility that the operation of other wireless devices may be hindered due to the failure of wireless devices or the illegal operation of wireless devices.
It is necessary to monitor the occurrence of such abnormal radio waves.

A conventional radio wave monitoring device uses a spectrum analyzer to determine whether the radio wave is used in the originally assigned frequency band, whether the radio wave level is abnormally high, or the occupied bandwidth of a radio wave. It is judged whether is within the standard. But with a spectrum analyzer,
To analyze each frequency component of the input signal (output signal of the antenna), the input signal and the frequency sweep signal (the signal whose frequency changes sequentially with time) are mixed and the mixed output is The level of each frequency component is sequentially extracted from the filter. In another conventional radio wave monitoring device, the input signal is digitized,
It is stored in memory and analyzed by computer.

[0004]

Since a spectrum analyzer uses a frequency sweep signal, it takes a certain amount of time to monitor a predetermined frequency range. That is, at a certain point of time, only a specific frequency component can be monitored. Further, in the monitoring using a computer, it takes time until the monitoring result is obtained. Therefore, none of the conventional techniques can monitor the radio wave in the predetermined frequency range in real time. In such a case, there is a possibility of failing to monitor an abnormal radio wave that occurs instantaneously.

Therefore, an object of the present invention is to provide a radio wave monitoring device capable of simultaneously monitoring radio waves in a predetermined frequency range in real time.

[0006]

A radio wave monitoring apparatus according to the present invention receives a plurality of band pass filters each receiving an output signal from an antenna for receiving a radio wave and having different pass frequencies (center frequencies), and the plurality of band pass filters. It comprises determination means for determining the output level from the pass filter and control means for setting the determination reference level of the determination means. The determination means monitors the radio waves by comparing the output levels of the plurality of band pass filters with the determination reference level. The present invention also provides a plurality of analog / digital converters for converting the output levels of the plurality of bandpass filters into digital signals, respectively, and digital signals from the plurality of analog / digital converters and / or output signals of the determination means. Further, the control means stops the accumulation of a new digital signal in the storage means after the determination means determines the abnormality. In this case, the control means may stop the accumulation of a new digital signal in the storage means after a predetermined period has elapsed since the determination means determined that the abnormality occurred. Further, the bandwidth and the pass frequency of each of the plurality of band pass filters may be variable, and the determining unit determines whether the bandwidth from the antenna is determined by the determination reference level and the determination pattern determined by the bandwidth and pass frequency of each of the plurality of band pass filters. Determine the output signal.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram of a first embodiment of the present invention. The antenna 10 captures radio waves from the air,
It is converted into an electric signal and supplied to the frequency converter 12. The frequency characteristic of the antenna 10 covers the frequency range to be monitored. Frequency converter 12
Reduces the output frequency of the antenna 10 by a constant frequency as a whole, and relaxes the signal processing condition of the circuit in the subsequent stage.
The amplifier 14 amplifies the output signal of the frequency converter 12 and supplies it to N (N is an arbitrary integer) band-pass filter (band-pass filter: BPF) 16.

Each of the bandpass filters 16 is (variable)
It is composed of a capacitor, a (variable capacitance) coil, a (variable) resistor, etc., and the center frequency and the bandwidth can be separately controlled by varying the values of these elements by a controller (control means) 26. The capacitor may be a variable capacitance diode, and a plurality of coils and resistors having different values may be prepared and a desired one may be selected. Of course, it may be a continuously variable element.

The N analog / digital (A / D) converters 18 convert the output signals from the corresponding band-pass filters 16 into digital signals, and supply the digital signals to the N judgment circuits (judgment means) 20. . The controller 26 appropriately sets the sampling frequency of the A / D converter 18 in accordance with the measured frequency range. The determination circuit 20 also compares the output level of each A / D converter 18 with each determination reference level from the controller 26, and outputs at least the comparison result and the digital output signal of the A / D converter 18. The digital output signal is supplied to the memory (eg, RAM) 22. Controller 26
Controls the write mode and read mode of the memory 22, and also supplies an address signal.

The controller 26 is, in addition to the above-mentioned control circuit,
It also includes a trigger circuit and a counter. The trigger circuit is
When at least one of the judgment circuits 20 generates an output outside the judgment reference level, the counter counts the clock signal,
After a lapse of a predetermined time, the memory 22 is switched from the write mode to the read mode so that a new digital signal is not stored.

As a duplicate explanation, regarding the controller 26,
Further description will be made. The controller 26 includes a variable clock generator, a digital latch circuit and a digital / analog (D / A) converter, an address counter, an OR gate, etc. for the above-mentioned control. The oscillation frequency of the variable clock generator is controlled by the control signal from the bus 24, and this clock signal is supplied to the A / D converter 18. In addition, the digital control signal from the bus 24 is accumulated in the digital latch circuit to select the element of the filter 16, and the digital signal of the latch circuit is D / A converted, so that the variable capacitance diode in the filter 16 is converted. Control. Further, the determination reference data from the bus 24 is latched in the latch circuit and set to the determination reference level for the determination circuit 20. Further, if the OR gate receives the outputs of the N judgment circuits 20, and even one judgment circuit generates an output signal, the programmable counter measures a predetermined period (time).
The preset value of the programmable counter is supplied from the bus 24. The address counter counts the clock signal from the clock generator and generates a clock signal for the memory 22.

The digital data read from the memory 22 is supplied to the bus 24. In this bus, a microprocessor (μP) 28 for performing various processes and this μP
A read-only memory (ROM) 30 that stores the processing program of FIG. 1, a random access memory (RAM) 32 that is a temporary storage element, a display 34 that displays monitoring results and set values, and a printer 36. , And an input device 38 such as a keyboard. Further, the control data for the controller 26 described above is transferred to the controller 26 by the μP 28 according to an instruction from the input device 34.

FIG. 2 is a display example of the display 34 showing an example of the result of radio wave monitoring. The horizontal axis represents frequency and the vertical axis represents time. Each vertical line represents the wireless output of each wireless device. Line E
All other lines are vertical lines, indicating that the frequency has not changed over time. However, the line E indicates that the frequency becomes unstable midway and the frequency band is moving in another frequency band. The present invention is a device that can capture such an abnormal state in real time. The operation for this will be further described.

In order to detect an abnormal state of radio waves, first,
The input device 34 is used to set a determination pattern as shown in FIG. Each radio frequency band is defined and its interval is also defined. In FIG. 3, the horizontal axis is frequency and the vertical axis is signal level. Of these, the shaded area is the normal range, and the blank area is the abnormal range. Since there is noise, areas below the noise level are shaded areas. Although multiple widths are shown on the lower side of FIG. 3,
“One bandwidth” corresponds to each bandwidth of the bandpass filter 16. Therefore, the bandwidth of each bandpass filter 16 is set to a predetermined one bandwidth. Next, the center frequency (pass frequency) of the filter 16 is sequentially shifted. For example, the first filter covers the first band from the left and the second filter is 2
The third filter covers the third band, the third filter covers the third band, and so on.

The judgment reference level of the judgment circuit 20 is determined with reference to FIG. That is, the determination reference levels of the first and second determination circuits (first and second circuits from the top) are noise levels (threshold levels for noise), and the reference level of the third determination circuit is a predetermined level. And Hereinafter, the reference level is similarly set in sequence. With such settings, the judgment pattern is completed. The setting status at this time is μ
This can be confirmed by P28 displaying the display 34 as shown in FIG. It may be printed out on the printer 36.

Next, the operation of FIG. 1 will be described with reference to the flowchart of FIG. In step 50, the trigger flag (a signal indicating that the trigger condition is satisfied) of the trigger circuit in the controller 26 is reset. In step 52, a radio wave is received from the antenna 10, and in step 54, the frequency converter 12 reduces the output signal frequency of the antenna 10.
In step 56, the amplifier 14 amplifies the output signal of the frequency converter 12. This amplified signal is referred to as step 58.
, And distributes to each band pass filter (BPF) 16.
These pass band filters pass signals of different frequency bands, and in step 60, the A / D converter 18 converts the filter pass signal into a digital signal. These signals pass through each of the determination circuits 20 and are sequentially accumulated in the memory 22. At this time, the control circuit 26 puts the memory 22 in the write mode and sends address signals that change sequentially. The address signal starts from the start address of the memory 22, returns to the start address when the end address is reached, and the same operation is repeated thereafter. That is, the memory 22 performs the overwriting operation from the second time.

In step 64, it is judged whether or not the trigger flag is 1, and if the result is no (if the trigger condition is not satisfied), the process proceeds to step 66. In step 66, it is judged whether or not the trigger condition is satisfied, that is, whether or not the condition is outside the judgment pattern. This can be done by having each digital comparator of the decision circuit 20 compare the digital signal of the A / D converter 18 with the decision reference digital level. When at least one of the judgment circuits 20 generates an output indicating that the judgment pattern 20 is out of the judgment pattern (step 6).
If 6 is yes), go to step 70 and set the trigger flag (set to 1). If step 66 is NO, the process returns to step 52.

If the trigger condition is satisfied (Yes) in step 66, the process proceeds to step 68. In step 68, it is determined whether or not predetermined data has been written in the memory 22. That is, when only the previous data satisfying the trigger condition is stored in the memory 22, the control circuit 26 immediately stops the write mode of the memory 22. When the data before and after the time when the trigger condition is satisfied is stored in the memory 22, the control circuit 26 stops the write mode after the time required to write half the total capacity of the memory 22 has passed after the trigger was satisfied. To do. Further, when the data after the time when the trigger condition is satisfied is stored in the memory 22, the control circuit 26
After the trigger is satisfied, the write mode is stopped after the time required to write the entire capacity of the memory 22 has elapsed. in this way,
The process returns from step 68 to step 52 until the write mode is stopped.

By the above-mentioned operation, the level state of each band before, after, or after the time when the abnormal radio wave is generated is stored in the memory 22.
Is accumulated in After that, the μP 28 reads the contents stored in the memory 22, processes them, and displays the monitoring result on the display 34 as shown in FIG. This display result is displayed on the printer 36.
You may print it out.

FIG. 5 is a block diagram of the second embodiment of the present invention. The same elements as in the embodiment of FIG. 1 are designated by the same reference numbers. The difference from the embodiment of FIG. 1 is that the A / D converter 18 is omitted and the decision circuit 20 makes the decision by an analog comparator. Therefore, the controller 26 also needs to convert the digital reference level to analog and supply it to the determination circuit 20. Further, the memory 22 stores only the determination result.

Although not shown, in connection with the embodiment of FIG. 1, an A / D converter is arranged after the amplifier 14,
The output of the / D converter may be supplied to the bandpass filter. In this case, it is necessary to configure each of the bandpass filters 16 with a digital filter. And digital
Each of the output signals of the filter 16 is supplied to the decision board 20. This embodiment has the advantage that only one A / D converter is required and the bandpass filter is a digital filter, so that the center frequency and bandwidth can be easily controlled.

Although only the preferred embodiments of the present invention have been described above, various modifications and changes can be made without departing from the spirit of the present invention. For example, the setting of the reference pattern may be graphically edited into the shape of FIG. 3 using a mouse. In this case, the microprocessor automatically calculates the set value from this graphic and sets the bandwidth and center frequency of each filter and the judgment reference level. Further, the bandwidth of each of the plurality of bandpass filters may be different.

[0023]

As described above, according to the present invention, since a plurality of band pass filters having different center frequencies receive the output of the antenna at the same time, high speed processing is possible, and radio waves in a predetermined frequency range can be simultaneously transmitted in real time. Can be monitored. Therefore, it is possible to reliably detect a radio wave that extends over each channel or a transient radio wave.

[Brief description of drawings]

FIG. 1 is a block diagram of a first preferred embodiment of the present invention.

FIG. 2 is a display example according to the present invention.

FIG. 3 is a diagram showing a reference pattern according to the present invention.

FIG. 4 is a flowchart illustrating the operation of the present invention.

FIG. 5 is a block diagram of a second preferred embodiment of the present invention.

[Explanation of symbols]

 10 Antenna 12 Frequency Converter 14 Amplifier 16 Band Pass Filter 18 A / D Converter 20 Judgment Means 22 Memory 24 Bus 26 Control Means 28 Microprocessor 30 ROM 32 RAM 34 Display 36 Printer 38 Input Device

Claims (7)

[Claims] 1. A plurality of band pass filters, each of which receives an output signal from an antenna for receiving a radio wave and has a different pass frequency, a judging means for judging an output level from the plurality of band pass filters, and the judging means. And a control means for setting the determination reference level of 1., the determination means compares the output levels of the plurality of band pass filters with the determination reference level to monitor the radio wave. 2. A plurality of analog-to-digital converters for converting the output levels of the plurality of band-pass filters into digital signals, respectively, and storage means for storing digital signals from the plurality of analog-to-digital converters. The radio wave monitoring device according to claim 1, wherein the control means stops the accumulation of the new digital signal in the storage means after the determination means has determined an abnormality. 3. The radio wave according to claim 2, wherein the control means stops the accumulation of the new digital signal in the storage means after a lapse of a predetermined period after the determination means determines the abnormality. Monitoring equipment. 4. The radio wave monitoring device according to claim 2, wherein the storage means also stores an output signal of the determination means. 5. The radio wave monitoring device according to claim 1, wherein the bandwidth and the pass frequency of each of the plurality of band pass filters are variable. 6. The determination means is the determination reference level,
The radio wave monitoring device according to claim 5, wherein the output signal from the antenna is determined by a determination pattern determined by the bandwidth and the pass frequency of each of the plurality of band pass filters. 7. An analog-digital converter for converting an output signal from the antenna into a digital signal is further provided between the antenna and the plurality of band pass filters, each of the plurality of band pass filters being a digital filter. The radio wave monitoring device according to claim 1, which is a filter.