JP2003036459A - Frequency characteristic measuring apparatus, authenticity discriminating apparatus, and medium frequency characteristic measuring method - Google Patents

Abstract

(57) Abstract: A compact and inexpensive frequency characteristic measuring device capable of measuring the frequency characteristic of a medium mixed with a resonator is provided. A truth discrimination device 1 irradiates a medium 2 with an impulse signal. The impulse signal is a signal containing all frequency components equally. For this reason, when all the resonators 3 mixed in the medium 2 are irradiated with the impulse signal, the electromagnetic waves of the resonance frequency are re-emitted. By detecting the intensity of the reflected wave from the medium 2 for each reception frequency of the reception unit B changed by the reception frequency control unit C, the medium 2
Measure the frequency characteristics of Thereby, downsizing of the main body and cost reduction can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency characteristic measuring device for irradiating a medium such as a bill, a bill, and a card with a broadband electromagnetic wave to measure the frequency characteristic of the medium, and a method for measuring the frequency characteristic of the medium.

Further, by applying the above frequency characteristic measuring device,
Authenticity determination device for determining authenticity of medium

[0003]

2. Description of the Related Art Conventionally, various types of media such as papers such as banknotes and securities and cards such as credit cards and ID cards have been forged and used in an unauthorized manner. Less than,
A forged medium is called a forged medium.

As a medium forgery prevention, it has been proposed to mix a resonator such as a conductive fiber into the medium so that the medium has an inherent frequency characteristic.

As is well known, a resonator has a property of electrically resonating when irradiated with an electromagnetic wave of a specific frequency and re-radiating the electromagnetic wave. The resonance frequency of the resonator changes depending on its length and the like. The medium mixed with the resonator has a certain frequency, that is, the resonance frequency of the mixed resonator,
When the electromagnetic wave is irradiated, the mixed resonator resonates and re-emits the electromagnetic wave. In this way, the medium has a characteristic of resonating when irradiated with an electromagnetic wave of a specific frequency due to the inclusion of the resonator.

By mixing a plurality of types of resonators having different resonance frequencies into the medium, it is possible to give the medium a characteristic of resonating when it is irradiated with electromagnetic waves of a plurality of frequencies.

Further, if the amount of the resonator mixed in the medium is made different for each resonance frequency, the size of the electromagnetic wave re-emitted from the medium (resonator) when the electromagnetic wave of that frequency is irradiated for each resonance frequency. You can make a difference in strength (strength).

As described above, by incorporating the resonator, the medium can have a unique frequency characteristic. Therefore,
By measuring the frequency characteristics of the medium, it is possible to easily determine whether or not the medium is a counterfeit medium, and it is considered effective in preventing counterfeiting of the medium.

[0009]

However, the conventional frequency characteristic measuring device for measuring the frequency characteristic of the medium changes the magnitude of the reflected wave from the medium while changing the frequency of the electromagnetic wave applied to the medium. It was a device for measuring the height. For this reason, the conventional device is provided with a configuration for changing the frequency of the electromagnetic wave in the transmitting unit that radiates the electromagnetic wave, and the configuration of the transmitting unit is complicated. Therefore, there is a problem that the device main body becomes large and expensive.

It is an object of the present invention to provide a small and inexpensive frequency characteristic measuring device capable of measuring the frequency characteristic of a medium mixed with a resonator.

It is another object of the present invention to provide an authenticity determining device which applies the above-mentioned frequency characteristic measuring device to determine the authenticity of a medium.

A further object of the present invention is to provide a frequency characteristic measuring method for measuring the frequency characteristic of a medium in which a resonator is mixed without changing the frequency of an electromagnetic wave applied to the medium.

[0013]

The frequency characteristic measuring apparatus of the present invention has the following constitution in order to solve the above-mentioned problems.

(1) Transmitting means for outputting pulsed electromagnetic waves, receiving means for receiving electromagnetic waves, receiving frequency control means for changing the receiving frequency of the receiving means, and each frequency of the electromagnetic waves received by the receiving means. A frequency characteristic measuring means for measuring the magnitude of the electromagnetic wave with respect to the frequency,
Is equipped with.

In the above structure, the transmitting means outputs pulsed electromagnetic waves. This pulsed electromagnetic wave is an impulse signal that uniformly contains all frequency components. When this impulse signal is applied to the medium in which the resonator is mixed,
All the resonators mixed in the medium re-radiate an electromagnetic wave having a frequency corresponding to the resonance frequency. In the receiving means,
The electromagnetic wave having the reception frequency changed by the reception frequency control means is received. The frequency characteristic measuring means measures the magnitude of the electromagnetic wave at the reception frequency.

Therefore, the frequency characteristic of the medium can be measured by irradiating the medium with the impulse signal from the transmitting means and changing the receiving frequency of the receiving means by the receiving frequency control means. Therefore, the structure for changing the frequency of the electromagnetic wave with which the transmission unit is irradiated to the medium is not required, and the size of the apparatus main body can be reduced and the cost can be reduced.

(2) The transmitting means is means for outputting pulsed electromagnetic waves at a constant cycle.

In the above arrangement, the transmitting section outputs a pulsed electromagnetic wave (impulse signal) at a constant cycle.

(3) The reception frequency control means is means for changing the reception frequency of the reception means in synchronization with the cycle of the pulsed electromagnetic wave.

In the above structure, the reception frequency control means changes the reception frequency of the reception means in synchronization with the cycle of the pulsed electromagnetic wave output from the transmission section.

(4) The reception frequency control means is means for continuously increasing or decreasing the reception frequency of the reception means.

In the above arrangement, the reception frequency control means changes the reception frequency of the reception means in a sawtooth shape with respect to time.

(5) The reception frequency control means is means for increasing or decreasing the reception frequency of the reception means stepwise.

In the above arrangement, the reception frequency control means changes the reception frequency of the reception means stepwise.

(6) The frequency characteristic measuring means measures, for each frequency of the received electromagnetic wave, the magnitude of the electromagnetic wave with respect to the frequency, and calculates the average value as the magnitude of the electromagnetic wave.

With the above arrangement, it is possible to suppress the influence of external noise and the like and to accurately measure the frequency characteristic of the medium irradiated with the electromagnetic wave.

Further, the authenticity discriminating apparatus of the present invention has the following configuration.

(7) The frequency characteristic measuring device according to any one of the above (1) to (6) is applied, and the frequency characteristic measured by the frequency characteristic measuring device is compared with a predetermined frequency characteristic. It is provided with a discriminating means for discriminating the authenticity of the medium.

In this configuration, if the frequency characteristic of a proper medium is set to the above-mentioned predetermined frequency characteristic, whether the medium is counterfeit or not, that is, the authenticity of the medium can be easily determined from the measured frequency characteristic. Can be determined.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an authenticity determination device according to an embodiment of the present invention. The frequency characteristic measuring device according to the embodiment of the present invention is applied to the authenticity determining device 1 of this embodiment.

In FIG. 1, 2 is a medium to be measured. The medium 2 will be described below as paper-like items such as banknotes and securities, but may be other types of medium such as cards such as credit cards and ID cards. The medium 2 is mixed with a resonator 3 (for example, quartz crystal or conductive fiber). The medium 2 is obtained by mixing the resonator 3 with a raw material of the medium 2 (a viscous raw material in which pulp is melted) and printing paper-like materials formed from this raw material, and is mixed with the medium 2. The resonator 3 cannot be taken out.

Further, a plurality of types of resonators having different resonance frequencies are added to the raw material. Furthermore, the amount of resonators added to the raw material is different for each type.

The medium 2 has, for example, the frequency characteristic shown in FIG. In FIG. 2, the horizontal axis is the frequency of the electromagnetic wave re-emitted from the resonator 3 mixed in the medium 2,
The vertical axis represents the intensity of this electromagnetic wave. As is well known, the resonator 3 re-radiates an electromagnetic wave having the resonance frequency when the electromagnetic wave having the same frequency as the resonance frequency is irradiated. FIG. 2 shows an example of frequency characteristics of the medium 2 in which three types of resonators 3 having different resonance frequencies are mixed. Moreover, since the amount of the resonator 3 mixed in the medium 2 is different for each type, the intensity peak is not constant. The resonance frequency intensity of the resonator 3 having a large mixing amount has a relatively large peak, and conversely, the resonance frequency intensity of the resonator 3 having a small mixing amount has a relatively small peak.

After the resonator 3 is put into the raw material, the raw material is sufficiently stirred and then the paper-like material is formed. Therefore, the resonator 3 mixed in the medium 2 formed from the same raw material is It is almost the same. Therefore, the frequency characteristics of the medium 2 molded from the same current amount are substantially the same. Further, by deciding the amount to be charged for each type of the resonator 3 with respect to a predetermined amount of raw material, the medium 2 having substantially the same frequency characteristics can be molded.

FIG. 3 is a diagram showing the configuration of the authenticity discrimination device according to the embodiment of the present invention. The authenticity determination device 1 is roughly divided into a transmitter A that irradiates a medium 2 with an electromagnetic wave and a medium 2.
The receiving unit B that receives the reflected wave (the electromagnetic wave re-emitted by the medium 2), the receiving frequency control unit C that changes the receiving frequency in the receiving unit B, the frequency characteristic of the medium 2 is measured, and 4 of frequency characteristic measuring section D for discriminating false (determining whether it is forged)
It is divided into two.

The transmitting section A is composed of a pulse generating circuit 11, an amplifier 12, a circulator 13 and an antenna 10. The pulse generation circuit 11 has a constant cycle t1 as shown in FIG.
It is a circuit for generating the impulse signal shown in FIG. The amplifier 12 amplifies and outputs the impulse signal generated by the pulse generation circuit 11. The circulator 13 sends the impulse signal input from the amplifier 12 to the antenna 10. The antenna 10 sends the impulse signal sent from the circulator 13 as an electromagnetic wave.

The receiving section B includes an antenna 10, a circulator 13, a mixer 14, and a bandpass filter 15 (hereinafter,
It is called BPF15. ). The electromagnetic wave received by the antenna 10 is transmitted by the circulator 13 to the mixer 1
4 is input. The mixer 14 mixes the signal of the frequency f0 input from the voltage control oscillator 16 (hereinafter, referred to as the VCO 16) described later and the signal of the frequency received by the antenna 10, and outputs the mixed signal. The BPF 15 passes a signal having a specific frequency.

The antenna 10 and the circulator 13 are shared by the transmitter A and the receiver B as shown in the figure.

The reception frequency control section C comprises a VCO 16 and a voltage generation circuit 17. The voltage generation circuit 17
As shown in FIG. 5, the output voltage is increased stepwise. The cycle of increasing (changing) the output voltage is the same as the cycle t1 of the impulse signal generated by the pulse generation circuit 11. The voltage generating circuit 17 keeps the output voltage substantially constant during this period t1. FIG. 5 shows an example in which the voltage generation circuit 17 outputs five levels of voltage.
The number of stages may be any number. As the number of steps is increased, the measurement accuracy of the frequency characteristic of the medium 2 is improved,
On the contrary, the measurement time becomes long.

Although the cycle of changing the output voltage of the voltage generating circuit 17 is synchronized with the generation cycle of the impulse signal in the pulse generating circuit 11, the rising timing of the impulse signal and the output of the voltage generating circuit 17 are synchronized. It is not particularly synchronized with the timing of changing the voltage.

As shown in the figure, the voltage generating circuit 17 returns the next output voltage to the lowest output voltage when the output voltage is the maximum, and then increases the output voltage stepwise.

As is well known, the VCO 16 outputs a signal having a frequency f0 according to the voltage input from the voltage generating circuit 17. That is, the frequency f0 of the signal output from the VCO 16 changes according to the change in the output voltage of the voltage generation circuit 17.

The frequency f1 of the signal passing through the BPF 15 is constant.

Here, the reception frequency of the receiving section B will be described.

The mixer 14 mixes the signal of the frequency f0 input from the VCO 16 and the signal of the frequency f received by the antenna 10, and the frequencies f-f0 and f + f.
A 0 signal (intermediate frequency signal) is generated and output. In the BPF 15 of this embodiment, the frequency f1 of the signal passing through is B1 = f-f0. Therefore, the antenna 1 passing through the BPF 15
The frequency f of the signal received at 0 is f = f1 + f0. As described above, the frequency f0 of the signal output from the VCO 16 changes according to the output voltage of the voltage generation circuit 17. Then, as the frequency f0 of the signal output from the VCO 16 changes, the frequency f of the signal received by the antenna 10 passing through the BPF 15 also changes. Therefore, the reception frequency of the receiver B changes according to the change of the frequency f0 of the signal output from the VCO 16.

The frequency characteristic calculation section D is composed of a detector 18, an amplifier 19, and a signal processing circuit 20. The detector 18 detects the signal that has passed through the BPF 15 and outputs it. The amplifier 19 amplifies the output of the detector 18 and inputs it to the signal processing circuit 20. The signal processing circuit 20 processes the input signal and measures the frequency characteristic of the medium 2. Further, the authenticity of the medium 2 is determined from the frequency characteristic of the medium 2. The configuration of the signal processing circuit 20 will be described later.

The operation of the authenticity discriminating apparatus 1 of this embodiment will be described below.

FIG. 6 is a flow chart showing the operation of the authenticity discriminating apparatus of this embodiment. The authenticity determination device 1 executes a frequency characteristic measurement process for measuring the frequency characteristic of the medium 2 for the target medium 2 for determining the authenticity (whether or not it is a forged medium) (s1).

FIG. 7 is a flowchart showing the frequency characteristic measuring process. In the pulse generation circuit 11, the impulse signal shown in FIG. 4 is generated and the output of the impulse signal is started from the antenna 10 (s11). The impulse signal is a signal including all frequency components as is well known. Further, as shown in FIG. 1, the medium 2 to be discriminated from the authenticity is placed at the position where the impulse signal output from the antenna 10 is irradiated.

Next, the authenticity discriminating apparatus 1 includes the voltage generating circuit 1
The operation of changing the output voltage of 7 in the stepwise manner shown in FIG. 5 is started (s12).

As described above, the generation cycle t1 of the impulse signal generated by the pulse generation circuit 11 and the time t1 during which the voltage generation circuit 17 holds the output voltage substantially constant are the same. Therefore, while the output voltage of the voltage generating circuit 17 is kept constant, one pulse signal is generated in the pulse generating circuit 11 and the medium 2 is irradiated with the impulse signal from the antenna 10.

Further, since the impulse signal is a signal which uniformly contains all frequency components, all the resonators 3 mixed in the medium 2 are irradiated with electromagnetic waves having the same frequency as the resonance frequency. When all the resonators 3 are irradiated with the electromagnetic wave having the same frequency as the resonance frequency, they re-emit the electromagnetic wave having the same frequency as the resonance frequency. The electromagnetic waves output from all the resonators 3 are received by the antenna 10 as a reflected wave from the medium 2 irradiated with the impulse signal. The antenna 10 receives a signal having the same frequency as the resonance frequency of the resonator 3 mixed in the medium 2.

In the receiving section B, the reception frequency changes according to the change in the frequency f0 of the signal input from the VCO 16 as described above. Further, the frequency f0 of the signal output from the VCO 16 changes according to the change in the output voltage of the voltage generating circuit 17. Further, the voltage generation circuit 17 changes the output voltage stepwise at the cycle t1, and the pulse generation circuit 11 generates the pulse signal at the cycle t1.

That is, the reception frequency control unit C determines the cycle t1.
The reception frequency of the receiving section B is changed by. On the other hand, the transmitter A irradiates the medium 2 with one impulse signal for each reception frequency of the receiver B changed by the reception frequency controller C. Therefore, the reception unit B receives the reflected wave from the medium 2 for each reception frequency changed by the reception frequency control unit C.

The reflected wave from the medium 2 received by the receiving section B is input to the frequency characteristic measuring section D. The frequency characteristic measuring unit D detects the signal input from the receiving unit B by the detector 18, amplifies the signal by the amplifier 19, and inputs the signal to the signal processing circuit 20.

Here, the signal processing circuit 20 will be described. FIG. 8 is a diagram showing the configuration of the signal processing circuit. The signal processing circuit 20 includes a CPU 21, a memory 22, and an A / D converter 23. The CPU 21 controls the operation of the signal processing circuit 20. The memory 22 stores programs executed by the CPU 21, data generated during operation, and the like. A
The / D converter 23 uses the signal amplified by the amplifier 19 as A /
D-convert. The A / D converter 23 includes a pulse generation circuit 1
The impulse signal generated in 1 is input.
The A / D converter 23 is configured to A / D-convert the reflected wave from the medium 2 by A / D-converting the input signal triggered by the impulse signal.

The signal processing circuit 20 having the above-mentioned configuration reflects the value A / D converted by the A / D converter 23 from the medium 2 for each reception frequency of the reception unit B changed by the reception frequency control unit C. The wave intensity is stored in the memory 22 (s1
3). In s13, the intensity of the reflected wave and the reception frequency of the receiving unit B at that time are stored in association with each other.

The authenticity discriminating apparatus 1 detects the intensity of the reflected wave from the medium 2 a predetermined number of times for each reception frequency of the reception section B which is changed by the reception frequency control section C, and stores it in the memory 23. When stored in (s14), the operation of the pulse generation circuit 11 is stopped (s15), and the operation of the voltage generation circuit 17 is stopped (s16). Then, for each reception frequency, the frequency characteristic of the medium 2 in which the average value of the intensities stored in the memory 23 a predetermined number of times is the intensity for that reception frequency is calculated (s17).

In this way, by irradiating the medium 2 with an impulse signal uniformly containing all frequency components and changing the reception frequency of the receiving section B for receiving the reflected wave from the medium 2, the medium 2 is changed. Since the frequency characteristic is measured, it is not necessary to change the frequency of the electromagnetic wave output to the transmitter A that irradiates the medium 2 with the electromagnetic wave.
Therefore, it is possible to reduce the size and cost of the device body.

In the measurement of the frequency characteristic of the medium 2, the intensity of the reflected wave from the medium 2 is detected a predetermined number of times for each reception frequency of the reception section B changed by the reception frequency control section C, and the average value thereof is detected. Is set to the intensity of the reception frequency, the influence of external noise or the like can be suppressed. Therefore, the frequency characteristic of the medium 2 can be accurately measured.

Further, since the generation cycle of the impulse signal in the pulse generation circuit 11 and the cycle in which the voltage generation circuit 17 changes the output voltage are the same, the reception frequency control section C changes the reception section B. The reflected wave from the medium 2 can be reliably detected for each reception frequency. Therefore, the frequency characteristic of the medium 2 can be measured efficiently without waste.

When the frequency characteristic measuring process of the medium 2 according to s1 is completed, the authenticity determining device 1 executes the authenticity determining process shown in FIG. 9 (s2). FIG. 9 is a flowchart showing the authenticity determination processing.

This processing is performed by the CPU 2 of the signal processing circuit 20.
Enabled by 1. The CPU 21 compares the reference frequency characteristic with the frequency characteristic of the medium 2 obtained in s1 (s2
1). The reference frequency characteristic is an appropriate frequency characteristic of the medium 2 and is stored in the memory 22.

The reference frequency characteristic is stored in a device (not shown) in the center, and the authenticity determining device 1 downloads the reference frequency characteristic from the device in the center as needed and stores it in the memory 22. The authenticity determination device 1 may be configured to store the above-mentioned reference frequency characteristics in an IC chip or a magnetic stripe provided on the medium 2.
Alternatively, the reference frequency characteristic may be read and stored in the memory 22.

When the CPU 21 determines in s21 that they are substantially the same (s22), it determines that the medium 2 is a proper medium (s23). It is determined that the medium is a forged medium (s24).

In step s21, for example, if the measured frequency characteristic of the medium 2 is within ± 5% of the reference frequency characteristic, it is determined that they are substantially in agreement, and if it is not within ± 5%, it is judged to be equal. I judge that I have not done it.

When it is determined in s2 that the counterfeit medium is a counterfeit medium, the genuine / counterfeit discriminating apparatus 1 displays a message indicating that the counterfeit medium is found on the display unit (not shown), or the counterfeit medium is output from the voice output unit. A notification process is performed to output a message indicating that has been found (s3, s4).

Therefore, the operator can recognize that the medium 2 whose frequency characteristic is measured is a counterfeit medium.

In the above embodiment, the voltage generating circuit 1
Although 7 is the circuit for increasing the output voltage stepwise, it may be a circuit for decreasing the output voltage stepwise as shown in FIG. Also in this case, the cycle of changing the output voltage is the same as the impulse signal generation cycle t1 in the pulse generation circuit 11.

Further, the voltage generating circuit 17 may be a circuit which changes the output voltage in a saw-tooth waveform (FIG. 10).
(See (B)). The pulse generation circuit 11 determines the cycle of the sawtooth wave.
An integer multiple of the impulse signal generation period t1 (n
When the above sawtooth wave is generated m times,
The intensity of the reflected wave from the medium 2 can be detected m times for n reception frequencies. By setting the average value as the intensity for each reception frequency, the influence of external noise and the like is suppressed, and the medium 2
The frequency characteristics of can be measured accurately.

It should be noted that the longer the cycle of the sawtooth wave (the larger the above n), the more the intensity of the reflected wave from the medium 2 is detected, and the frequency characteristic of the medium 2 is detected. The measurement accuracy can be improved.

When the cycle of the sawtooth wave is not an integral multiple (n times) of the impulse signal generation cycle t1 in the pulse generation circuit 11, the reception frequency for detecting the intensity of the reflected wave from the medium 2 changes for each sawtooth wave. To do. Therefore, the intensity of the reflected wave from the medium 2 can be detected for more reception frequencies, and the measurement accuracy of the frequency characteristic of the medium 2 can be improved.

Further, the voltage generating circuit 17 may be a circuit which changes the output voltage into a reverse sawtooth waveform (FIG. 10).
(See (C)). The cycle of the reverse sawtooth wave may be an integer multiple (n times) of the impulse signal generation cycle t1 in the pulse generation circuit 11, or may not be an integer multiple. Also in this case, the same effect as the above sawtooth wave can be obtained.

[0074]

As described above, according to the present invention, the receiving frequency of the receiving means for receiving the reflected wave from the medium is changed by irradiating the medium with the impulse signal uniformly including all frequency components. By doing so, the frequency characteristic of the medium is measured. Therefore, it is not necessary to have a configuration for changing the frequency of the electromagnetic wave output to the transmitting unit that irradiates the medium with the electromagnetic wave. Therefore, it is possible to reduce the size and cost of the device body.

The main body can be downsized and the cost can be reduced.

In measuring the frequency characteristic of the medium,
For each reception frequency of the reception means changed by the reception frequency control means, the intensity of the reflected wave from the medium is detected a predetermined number of times, and the average value thereof is used as the intensity of this reception frequency. The influence can be suppressed. Therefore, the frequency characteristic of the medium can be accurately measured.

[Brief description of drawings]

FIG. 1 is a diagram showing a true / false determination device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of frequency characteristics of a medium.

FIG. 3 is a diagram showing a configuration of a true / false determination device according to an embodiment of the present invention.

FIG. 4 is a diagram showing an impulse signal generated by the pulse generation circuit of the authenticity determination device according to the embodiment of the present invention.

FIG. 5 is a diagram showing voltages generated in the voltage generation circuit of the authenticity determination device according to the embodiment of the present invention.

FIG. 6 is a flowchart showing an operation of the authenticity determining device according to the embodiment of the present invention.

FIG. 7 is a diagram showing a frequency characteristic measuring process of the authenticity determining device according to the embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of a signal processing circuit of the authenticity determination device according to the embodiment of the present invention.

FIG. 9 is a diagram showing a true / false determination process of the true / false determining apparatus according to the embodiment of the present invention.

FIG. 10 is a diagram showing a voltage generated by a voltage generation circuit of a true / false determination device according to another embodiment of the present invention.

[Explanation of symbols]

1-Authenticity determination device 2-medium 3-resonator A-transmitter B-Reception unit C-Reception frequency control unit D-frequency characteristic measuring section 10-antenna 11-Pulse generation circuit 12-amplifier 13-circulator 14-mixer 15-band pass filter (BPF) 16-Voltage control transmitter 17-Voltage generation circuit 18-Detector 19-amplifier 20-Signal processing circuit 21-CPU

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Claims (8)

[Claims] 1. A transmitting means for outputting a pulsed electromagnetic wave, a receiving means for receiving the electromagnetic wave, a receiving frequency control means for changing the receiving frequency of the receiving means, and a frequency for each electromagnetic wave received by the receiving means. And a frequency characteristic measuring device for measuring the magnitude of the electromagnetic wave with respect to the frequency. 2. The frequency characteristic measuring apparatus according to claim 1, wherein the transmitting means is means for outputting pulsed electromagnetic waves at a constant cycle. 3. The frequency characteristic measuring apparatus according to claim 2, wherein the reception frequency control means is means for changing the reception frequency of the reception means in synchronization with the cycle of the pulsed electromagnetic wave. 4. The frequency characteristic measuring device according to claim 1, wherein the reception frequency control means is means for continuously increasing or decreasing the reception frequency of the reception means. 5. The frequency characteristic measuring device according to claim 1, wherein the reception frequency control means is means for increasing or decreasing the reception frequency of the reception means in a stepwise manner. 6. The frequency characteristic measuring means measures, for each frequency of the received electromagnetic wave, the magnitude of the electromagnetic wave with respect to the frequency a plurality of times, and calculates the average value as the magnitude of the electromagnetic wave. The frequency characteristic measuring device according to any one of 1. 7. The frequency characteristic measuring device according to claim 1 is applied, and the frequency characteristic measured by the frequency characteristic measuring device is compared with a predetermined frequency characteristic to determine whether the medium is true or false. An authenticity determination device having a determination means for determining 8. A step of receiving a reflected wave from the medium while irradiating the medium with a pulsed electromagnetic wave, a step of changing a reception frequency of the reflected wave from the medium, and a step of changing the received wave of the reflected wave from the medium. A method for measuring frequency characteristics of a medium, which comprises a step of measuring the magnitude of an electromagnetic wave for each reception frequency to obtain frequency characteristics.