JP4871585B2 - Method and program for measuring occupied bandwidth of millimeter-wave radio signal - Google Patents

Description

  The present invention relates to a method for measuring an occupied band of a millimeter-wave radio signal occupying a wide band and a program thereof.

  Conventionally, there is an increasing demand for digital data transmission over a wide band in wireless communication. For transmission of such broadband digital data, it is necessary to use a carrier signal in the millimeter wave radio band, which is a high frequency (see Patent Document 1).

  However, since the measurement band of a normal spectrum analyzer is about 40 GHz, it is difficult to measure the occupied band of the radio wave in the millimeter wave region exceeding 100 GHz without any change.

Therefore, conventionally, as shown in FIG. 5, a method of down-converting the measured frequency of the RF signal into the measurement band of the spectrum analyzer 1 using the local signal 6 and the mixer 2 is used.
JP 2002-353739

  However, in the conventional measurement method as described above, when a signal in which a strong carrier component is left as generated when the carrier signal is directly ASK modulated is measured, the data signal modulated with the carrier signal by intermodulation in the mixer is measured. Since a frequency component corresponding to the basic component of the data signal is generated from 0 Hz generated by the above mixing, it is difficult to accurately measure the occupied band.

  The present invention has been made in view of the above, and an object thereof is to measure an accurate occupied band in a millimeter-wave radio signal whose occupied band exceeds the measurement band of a spectrum analyzer.

In order to achieve the above object, the present invention according to claim 1 is directed to a millimeter-wave radio signal that is measured by down-converting a millimeter-wave radio signal into a measurement band of a spectrum analyzer using a local signal and a mixer. In the occupied band measuring method, the step of down-converting the millimeter-wave radio signal by the mixer using the two types of local signals and the power spectrum of the two types of IF signals generated by the down-conversion are measured by a spectrum analyzer. A frequency region including a fundamental frequency component of a data signal that modulates a carrier signal from 0 Hz is excluded from the power spectrum, and the power spectrum obtained in the excluding step is a frequency of the millimeter wave radio signal. According to the step of converting into the band and the two converted measurement results . Interpolating to obtain an occupied band of the millimeter-wave radio signal .

Further, the invention of claim 2, in claim 1, wherein the millimeter-wave radio signal is directly intensity modulated runs a carrier signal by a data signal.

According to a third aspect of the present invention, there is provided a computer-readable millimeter-wave radio signal for down-converting and measuring a millimeter-wave radio signal within a measurement band of a spectrum analyzer using a local signal and a mixer. In the occupied band measurement program, the millimeter wave radio signal is down-converted by the mixer using the two types of local signals, and the power spectrum of the two types of IF signals generated by the down-conversion is measured by a spectrum analyzer. steps and, a step of excluding the frequency domain from the power spectrum that includes the fundamental frequency of the data signal for modulating a carrier signal from 0 Hz, the frequency band of the power spectrum obtained in the step of excluding the millimeter-wave radio signal a step of converting the two mentioned above in terms By interpolating the measurements to execute the steps of obtaining a band occupied by the millimeter-wave radio signal to the computer.

Further, the present invention according to claim 4, in claim 3, wherein the millimeter-wave radio signal is directly intensity modulated runs a carrier signal by a data signal.

  According to the present invention, an accurate occupied band can be measured in a millimeter-wave radio signal whose occupied band exceeds the measurement band of a spectrum analyzer.

<First Embodiment>
1 and 2 are explanatory diagrams for explaining the millimeter wave radio signal occupation band measurement system according to the present embodiment.

  FIG. 1 shows a mixer 2 to which an RF signal is input, a spectrum analyzer 1 for displaying an output from the mixer 2 in a spectral distribution, and a local signal source for inputting two types of local signals to the mixer 2. 4 and 5 and a switch 3 for switching between two types of local signals input to the mixer 2 are shown.

In the millimeter wave radio signal occupation band measuring system shown in FIG. 1, a millimeter wave radio signal having a data signal component of the fundamental frequency component fd in both bands centered on the carrier frequency of the carrier frequency fc is supplied to the mixer 2 as RF. Input as a signal. The RF signal input to the mixer 2 in FIG. 1 is a fundamental frequency component fc and fc−fd and fc + fd on both sides of the fundamental frequency component fc . The mixer 2 also receives a signal of frequency fl1 from the local signal source 4 as a local signal.

Next, the RF signal input to the mixer 2 is down-converted into frequency components of fc−fd−fl _{1 to} fc + fd−fl ₁ . However, since the carrier signal component remains strong in the millimeter wave radio signal generated by directly modulating the intensity of the carrier signal, components 0 to fd due to the mixing of the carrier signal and the data signal component also occur at the same time.

  Therefore, in calculating the occupied band, an accurate occupied band excluding the influence of the intermodulation of the mixer 2 can be obtained by integrating the spectrum intensity in the frequency domain excluding the frequency components of 0 to fd to obtain the total power. It becomes possible.

However, since the frequency difference between the RF signal and the LO signal (local signal fl ₁ from the local signal source 4) is limited in the normal mixer 2, the band of the IF signal (intermediate frequency) is limited. In addition, since there is an upper limit in the measurement band of the spectrum analyzer 1, it is difficult to down-convert an RF signal in a wide frequency range.

Therefore, as shown in FIG. 2, a second signal having a frequency of fl ₂ (fl ₁ > fl ₂ ) is used as a local signal in addition to fl ₁ , and the millimeter wave signal component is reduced using these two types of signals. Convert.

First, when an RF signal is mixed with a local signal having a frequency fl ₁ , it is down-converted by fl ₁ . This mixed signal is an IF signal, which is measured by the spectrum analyzer 1 as shown in FIG. In this case, the waveform displayed in the region of fd to fs of the spectrum analyzer 1 observes the mixing result of the original RF signal in the frequency region of fd + fl _{1 to} fs + fl ₁ .

On the other hand, when the local signal to fl _2, the waveform that is displayed in the area of fd~fs of the spectrum analyzer 1, the mixing results of fd + fl ₂ ~fs + fl ₂ of those in the frequency domain of the original RF signal It will be observing.

When the upper limit of the measurement band of the spectrum analyzer 1 is fs, the internal frequency fd + fl _{1 to} fs + fl of the millimeter wave radio signal using the frequency range of fd to fs among the signal components down-converted using the local signal of the frequency fl ₁ calculating a _first range, among the down-converted signal components using a local signal of a frequency fl _2, it calculates a range of fd + fl ₂ ~fd + fl ₁ using the frequency range of fd~fd + fl ₁ -fl _2.

By combining the results of both, it is possible to measure over a wide frequency range of fd + fl _{2 to} fs + fl ₁ (where fl ₁ > fl ₂ ) in the RF signal.

In this measurement, how many times the power value of the RF signal of the corresponding frequency becomes the power value of the IF signal is checked for each frequency, and a correspondence table (not shown) is created in advance. Then, the power value of the IF signal in the frequency region of fd to fs is measured for each of the case where the frequency of the local signal is set to fl ₁ and the case where it is set to fl ₂ as described above. By calculating the corresponding RF signal from the measured value using the correspondence table, the power spectrum of the RF signal in the frequency domain fd + fl _{2 to} fs + fl ₁ can be obtained.

This measurement procedure is shown in FIG. FIG. 3 shows a flowchart for explaining processing for performing measurement in the frequency range of fd + fl _{2 to} fs + fl ₁ with the spectrum analyzer 1.

First, the IF frequency 0 to fs down-converted using the frequency fl _{1 of the} LO signal is measured (S1).

Then, to convert the results of the IF frequency fd~fs the RF frequency band _{fd + fl 1 ~fs + fl 1} (S2).

On the other hand, the IF frequency 0 to fs down-converted using the frequency fl _{2 of the} LO signal is measured (S3).

Then, to convert the results of the IF frequency fd~fd ₊ fl 1 -fl ₂ to RF frequency band _{fd + fl 2 ~fd + fl 1} (S4).

Then, the conversion results of S2 and S4 are combined as measurement results to obtain the occupied band of the RF frequency band fd + fl _{2 to} fs + fl ₁ (S5).

  By using the processing described above, it is possible to measure in a wide RF frequency range even if the components 0 to fd are removed from the downconverted signal component in order to remove the influence of the intermodulation.

<Second Embodiment>
FIG. 4 is an explanatory diagram for explaining the second embodiment. FIG. 4 shows a mixer 2 to which an RF signal (data signal) is input, a local signal source 6 that generates a local signal and inputs the local signal, and a spectrum analyzer 1 that observes the output signal of the mixer 2. Has been.

  In the first embodiment described above, the case of a millimeter wave signal obtained by directly modulating the intensity of the carrier signal fc with the data signals fc−fd and fc + fd is shown. However, in the second embodiment, the IF signal is used for the data signal. Is used, and a millimeter-wave radio signal generated by single-sideband modulation of the carrier signal is used after up-conversion to IF signals of frequencies fx to fx + fd.

  In a normal radio system, a carrier signal is transmitted after being suppressed by a filter or the like. In a radio communication system using the self-heterodyne method, for example, a carrier signal component fc and a single signal are used for the purpose of suppressing the local signal source 6 on the receiving side. The sideband signal components fc + fx and fx + fd have similar signal strengths.

  When such an RF signal is input to the mixer 2, the component due to the intermodulation appears as components fx to fx + fd. Therefore, for the calculation of the occupied band, fx + fd + fl to fs + fl of the millimeter wave signal frequency components are calculated using the components of fx + fd to fs of the down-converted signal.

  Note that, as in the first embodiment, the measurement frequency region of the RF signal may be expanded by using two types of local signal components.

  In the first and second embodiments described above, when the occupied band is measured by down-converting the millimeter-wave radio signal by the mixer 2, the data signal modulated from 0 Hz is included in the down-converted signal. It is characterized in that the occupied band is calculated using the result of excluding the frequency region including the basic component, and the measurement frequency band is expanded by using two LO signals.

  A measurement system using down-conversion by the mixer 2 in order to measure the occupied band of the millimeter wave radio signal having a frequency component equal to or higher than the measurement band of the spectrum analyzer 1 by expanding the measurement frequency band by such processing. Therefore, it is possible to accurately measure the occupied band without the influence of intermodulation in the mixer 2.

  In addition, the measurement range of the RF signal can be increased by using two types of local signal frequencies.

  The embodiment described above is not only a method for measuring the occupied band in the millimeter wave radio signal occupied band measurement system, but also each process of calculation processing and signal processing for executing processing corresponding to the measurement method. A computer program composed of steps is also included in the technical category, and the measurement method can be executed by installing this computer program in a computer.

An explanatory view for explaining a millimeter wave radio signal occupation band measurement system concerning a 1st embodiment is shown. An explanatory view for explaining a millimeter wave radio signal occupation band measurement system concerning a 1st embodiment is shown. The flowchart for demonstrating the flow of a process in the millimeter wave radio signal occupation band measurement system based on 1st Embodiment is shown. An explanatory view for explaining a millimeter wave radio signal occupation band measuring system concerning a 2nd embodiment is shown. The schematic block diagram of the millimeter wave radio signal occupation band measurement system by a prior art is shown.

Explanation of symbols

1 Spectrum analyzer 2 Mixer 3 Switch 4 5 Local signal source

Claims (4)

In the occupied band measurement method for millimeter-wave radio signals that uses a local signal and a mixer to down-convert and measure the millimeter-wave radio signal within the spectrum analyzer measurement band,
Downconverting the millimeter-wave radio signal with the mixer using the two types of local signals;
Measuring power spectra of the two types of IF signals generated by the down-conversion using a spectrum analyzer;
Excluding a frequency region including a fundamental frequency component of a data signal that modulates a carrier signal from 0 Hz from the power spectrum ;
Converting the power spectrum obtained in the excluding step into a frequency band of the millimeter wave radio signal;
Interpolating the converted two measurement results to obtain an occupied band of the millimeter wave radio signal ;
A method for measuring an occupied band of a millimeter-wave radio signal, comprising: The millimeter wave radio signal is
Occupied bandwidth measurement method of millimeter-wave wireless signals according to claim 1, characterized in that it is directly intensity modulated runs a carrier signal by a data signal. In an occupied band measurement program for a millimeter-wave radio signal readable by a computer for down-converting and measuring a millimeter-wave radio signal within the measurement band of a spectrum analyzer using a local signal and a mixer,
Downconverting the millimeter-wave radio signal with the mixer using the two types of local signals;
Measuring power spectra of the two types of IF signals generated by the down-conversion using a spectrum analyzer;
Excluding a frequency region including a fundamental frequency component of a data signal that modulates a carrier signal from 0 Hz from the power spectrum ;
Converting the power spectrum obtained in the excluding step into a frequency band of the millimeter wave radio signal;
Interpolating the converted two measurement results to obtain an occupied band of the millimeter wave radio signal ;
The program for causing the computer to execute an occupied band measurement program for millimeter-wave radio signals. The millimeter wave radio signal is
Occupied band measurement program of the millimeter wave radio signals according to claim 3, characterized in that it is directly intensity modulated runs a carrier signal by a data signal.

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