JP4806523B2 - Signal mixing apparatus, method, program, recording medium, and spectrum analyzer - Google Patents

Description

  The present invention relates to a reduction in measurement error by a mixer included in a spectrum analyzer.

  Conventionally, a spectrum in a frequency domain of a signal under measurement has been measured using a spectrum analyzer (see, for example, Patent Document 1). The spectrum analyzer uses a mixer to mix the signal under measurement with the local signal and convert the frequency of the signal under measurement.

JP 2001-59852 A

  However, spurious is generated by the mixer included in the spectrum analyzer. As a result, the spectrum in the frequency domain of the signal under measurement may be erroneously measured.

  Therefore, an object of the present invention is to reduce measurement errors caused by a mixer included in a spectrum analyzer.

  According to the signal mixing device of the present invention, the first local signal generating means for generating the first local signal, and the first mixing means for mixing the measurement target signal and the first local signal and outputting a signal having an intermediate frequency And a first local frequency changing means for changing the frequency of the first local signal while avoiding a spurious frequency corresponding value corresponding to the spurious frequency generated by the first mixing means.

  According to the signal mixing device configured as described above, the first local signal generating means generates the first local signal. The first mixing unit mixes the measurement target signal and the first local signal, and outputs an intermediate frequency signal. The first local frequency changing means changes the frequency of the first local signal while avoiding a spurious frequency corresponding value corresponding to the spurious frequency generated by the first mixing means.

  Further, according to the signal mixing device of the present invention, the first local frequency changing means uses, as the frequency of the first local signal, a value obtained by adding a predetermined shift value to the spurious frequency corresponding value instead of the spurious frequency corresponding value. You may do it.

  The signal mixing device according to the present invention includes a second local signal generating unit that generates a second local signal having a predetermined frequency, a second mixing unit that mixes the output of the first mixing unit and the second local signal, When the local frequency changing means uses the value obtained by adding a predetermined shift value to the spurious frequency corresponding value instead of the spurious frequency corresponding value as the frequency of the first local signal, the frequency of the second local signal is changed from the predetermined frequency. Second local frequency changing means that subtracts a predetermined shift value may be provided.

  In the signal mixing device according to the present invention, the spurious frequency may be determined based on values taken by the carrier frequency, the intermediate frequency, and the first local signal of the measurement target signal.

  Further, the signal mixing device according to the present invention includes first spurious frequency generation means for generating a value obtained by adding the intermediate frequency to the carrier frequency of the measurement target signal multiplied by a positive integer, and a value taken by the frequency of the first local signal. A second spurious frequency generating means for generating a value obtained by multiplying a positive integer multiple by a coincidence detecting means for detecting a generated result when the generated results of the first spurious frequency generating means and the second spurious frequency generating means match. You may make it provide the spurious frequency determination means which determines a spurious frequency based on the detection result and intermediate frequency of a detection means.

  Further, the signal mixing device according to the present invention may include an analysis unit that analyzes the measurement target signal based on an output of the signal mixing device, and a display unit that displays an analysis result of the analysis unit.

  In the signal mixing method according to the present invention, the first local signal generating unit generates the first local signal, and the first mixing unit mixes the measurement target signal and the first local signal. Then, the first mixing step of outputting the intermediate frequency signal and the first local frequency changing means avoid the spurious frequency corresponding value corresponding to the spurious frequency generated by the first mixing means and reduce the frequency of the first local signal. And a first local frequency changing step for changing.

  The program according to the present invention includes first local signal generation means for generating a first local signal, and first mixing means for mixing the measurement target signal and the first local signal and outputting an intermediate frequency signal. A program for causing a computer to perform signal mixing processing in a signal mixing device having a first local signal that changes a frequency of the first local signal while avoiding a spurious frequency corresponding value corresponding to a spurious frequency generated by the first mixing means. A program for causing a computer to execute local frequency change processing.

  The recording medium according to the present invention includes a first local signal generating unit that generates a first local signal, a first mixing unit that mixes the measurement target signal and the first local signal, and outputs a signal having an intermediate frequency. A computer-readable recording medium that records a program for causing a computer to perform signal mixing processing in a signal mixing apparatus having a spurious frequency corresponding value corresponding to a spurious frequency generated by the first mixing means, The computer-readable recording medium stores a program for causing a computer to execute a first local frequency changing process for changing the frequency of the first local signal.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a spectrum analyzer 1 according to an embodiment of the present invention. The spectrum analyzer 1 includes a signal mixing device 4, an A / D converter 42, an analysis unit 44, and a display (display means) 46. The spectrum analyzer 1 measures and displays a frequency spectrum of an RF (Radio Frequency) signal that is a measurement target signal.

  FIG. 2 is a diagram illustrating an example of a frequency spectrum of a measurement target signal. The measurement target signal has a carrier signal 2a and a spurious 2b. The carrier signal 2a is an original signal of the signal to be measured, and the power is higher than other frequencies. In the example of FIG. 2, it is a component of 2.11 GHz (this is expressed as Fsig). However, the measurement target signal has a spurious 2b different from the original signal. Using the spectrum analyzer 1, the difference [dBc] between the power of the carrier signal 2a and the power of the spurious 2b is measured. This is the measurement of the spurious 2b. Spurious measurement is adopted as an evaluation item for mobile communication.

  The signal mixing device 4 mixes the RF signal with the first local signal, the second local signal, and the third local signal, and outputs a low-frequency signal capable of A / D conversion.

  The A / D converter 42 converts the analog signal output from the signal mixing device 4 into a digital signal. The analysis unit 44 analyzes the measurement target signal based on the digital signal output from the A / D converter 42. For example, the relationship between frequency and power is obtained. The display (display means) 46 displays the analysis result (for example, the relationship between frequency and power) by the analysis unit 44.

  FIG. 3 is a diagram illustrating an example of a display mode of the display 46. In addition to the carrier signal 2a and the spurious 2b, the no-input spurious 2c is displayed as the frequency spectrum of the measurement target signal. The no-input spurious 2c is a spurious generated by the first multiplier 14 described later, and is not included in the measurement target signal (see FIG. 2). Therefore, measuring the difference [dBc] between the power of the carrier signal 2a and the power of the no-input spurious 2c does not measure the spurious of the measurement target signal.

  However, it is difficult to discriminate the no-input spurious 2c and the spurious 2b from only the display 46. Therefore, the difference [dBc] between the power of the carrier signal 2a and the power of the non-input spurious 2c may be erroneously set as a measurement result of the spurious of the measurement target signal. In the example of FIG. 3, the no-input spurious 2c is a component of 0.9493 GHz.

  Returning to FIG. 1, the signal mixing device 4 includes a first local oscillator 12, a first multiplier (first mixing means) 14, a bandpass filter 16, a second local oscillator 22, a second multiplier (second multiplier). Mixing means) 24, a third local oscillator 32, a third multiplier 34, and a local frequency control unit 50.

  The first local oscillator 12 generates a first local signal Lo. The frequency of the first local signal Lo is expressed as Flo. In this embodiment, Flo takes a value from 4.4314 GHz to 7.9314 GHz (= 4.4314 + 3.5). The frequency displayed on the display 46 (referred to as “display frequency”) is a value obtained by subtracting 4.4314 GHz (which is the frequency Fif of the IF signal that has passed through the bandpass filter 16 as will be described later) from Flo. Therefore, the display frequency is 0 to 3.5 GHz (see FIG. 3).

  The first multiplier (first mixing means) 14 performs mixing by multiplying the RF signal that is the measurement target signal by the first local signal. The frequency of the signal output from the first multiplier 14 is a value obtained by subtracting the frequency of the RF signal from Flo. However, since the first multiplier 14 generates the no-input spurious 2c, the signal output from the first multiplier 14 includes frequency components of n · Flo −m · (frequency of the RF signal) (n and m is a positive integer).

The band pass filter 16 passes a signal of a component in a predetermined frequency band from the signal output from the first multiplier 14. A signal that has passed through the bandpass filter 16 is referred to as an IF (Intermediate Frequency) signal. The frequency of the IF signal is called the intermediate frequency and is expressed as Fif. In this embodiment, Fif
= 4.4314GHz ± 100MHz. However, for convenience of explanation, it is assumed that Fif = 4.4314 GHz.

  Since Fif = 4.4314 GHz, the analysis unit 44 obtains the power of the RF signal when Fif = 4.4314 GHz.

  FIG. 4 is a diagram for explaining the frequency component of the RF signal for which the analysis unit 44 obtains power, and shows a carrier signal (FIG. 4A) and a no-input spurious (FIG. 4B). .

Referring to FIG. 4A, the frequency of the signal output from the first multiplier 14 is a value obtained by subtracting the frequency of the RF signal from Flo.
The power of the frequency component with the value obtained by subtracting 4.4314 GHz) will be obtained. For example, Flo is 0.9493 + 4.4314
When [GHz] is reached, the power of the component of Flo−Fif = (0.9493 + 4.4314) GHz−4.4314 GHz = 0.9493 GHz in the RF signal is measured.

  However, referring to FIG. 4B, the frequency of the signal output from the first multiplier 14 may be n · Flo−m · (RF signal frequency) (n and m are positive integers). ). When n · Flo −m · (RF signal frequency) = Fif, the power of the frequency component of the RF signal at that time is also measured. For example, when n = 2 and m = 3, the power of the frequency component of (2Flo-Fif) / 3 in the RF signal is also obtained. For example, it is assumed that Flo = 0.9493 + 4.4314 [GHz]. Then, the power of the frequency component of (2Flo−Fif) /3=2.11 [GHz] is also obtained. However, this measurement result (power of the 2.11 GHz component) is displayed on the display 46 as the power of the component of Flo−4.4314 GHz = 0.9493 GHz (see FIG. 3).

  Returning to FIG. 1, the second local oscillator 22 generates a second local signal. The frequency of the second local signal is a predetermined frequency (4.01 GHz in this embodiment), but there are exceptions as will be described later. As a result, a signal in a band centered at 4.4314 GHz−4.01 GHz = 421.4 MHz is obtained.

  The second multiplier (second mixing means) 24 performs mixing by multiplying the IF signal that has passed through the bandpass filter 16 and the second local signal.

  The third local oscillator 32 generates a third local signal.

  The third multiplier 34 performs mixing by multiplying the output of the second multiplier 24 and the third local signal. A signal having a frequency obtained by subtracting the frequency of the third local signal from the output frequency of the second multiplier 24 is obtained. The output frequency of the third multiplier 34 is low enough to allow A / D conversion.

  The local frequency control unit 50 controls the first local oscillator 12 to sweep the frequency Flo of the first local signal Lo. In addition, the local frequency control unit 50 controls the second local oscillator 22 to determine the frequency of the second local signal.

  FIG. 5 is a functional block diagram showing the configuration of the local frequency control unit 50. The local frequency control unit 50 includes a no-input spurious calculation unit 51, a no-input spurious recording unit 52, a first local frequency sweep instruction unit (first local frequency changing means) 54, a shift value recording unit 56, and a second local frequency change instruction. Section (second local frequency changing means) 58.

  The no-input spurious calculator 51 calculates the frequency at which the no-input spurious 2c is generated. The configuration of the no-input spurious calculation unit 51 is shown in FIG. The no-input spurious calculation unit 51 includes a user interface 51a, a carrier frequency recording unit 51b, an intermediate frequency recording unit 51c, a first spurious frequency generation unit 51d, a local frequency recording unit 51e, a second spurious frequency generation unit 51f, and a display range recording unit. 51g, a coincidence detection unit 51h, and a spurious frequency determination unit 51i.

  The user interface 51a is used by the user of the spectrum analyzer 1 to input the carrier frequency of the measurement target signal and the display range of the frequency, and is, for example, a key.

  The carrier frequency recording unit 51b records a carrier frequency Fsig that is the frequency of the carrier signal 2a. In the example of FIG. 2, it is 2.11 GHz.

  The intermediate frequency recording unit 51c records an intermediate frequency that is the frequency of the IF signal. In this embodiment, it is 4.4314 GHz.

  The first spurious frequency generation unit 51d calculates the first spurious frequency = m · Fsig + Fif (m is a positive integer). For example, m = 1, 2, 3. FIG. 7 shows the calculation result of the first spurious frequency. In FIG. 7, the horizontal axis represents the display frequency (0 to 3.5 GHz) displayed on the display 46. Regardless of the display frequency, the first spurious frequency is constant.

  The local frequency recording unit 51e records the frequency Flo of the first local signal Lo. The frequency Flo takes a value from 4.4314 GHz to 7.9314 GHz (= 4.4314 + 3.5). That is, the display frequency is +4.4314 GHz.

  The second spurious frequency generation unit 51f calculates the second spurious frequency = n · Flo (n is a positive integer). For example, n = 1,2,3. The calculation result of the second spurious frequency is shown in FIG. In FIG. 8, the horizontal axis represents the display frequency and Flo. When Flo is taken on the horizontal axis, the second spurious frequency is a straight line passing through the origin. When the display frequency is taken on the horizontal axis, when the display frequency = 0, the second spurious frequency = n · 4.4314 is a straight line having an inclination n.

  The display range recording unit 51g records a display frequency range. In the present embodiment, the display range is 0 to 3.5 GHz.

  The coincidence detector 51h detects the first spurious frequency (= second spurious frequency) when the first spurious frequency and the second spurious frequency coincide. The spurious frequency determination unit 51i determines a spurious frequency (a frequency at which the no-input spurious 2c is generated) based on the detection result of the coincidence frequency detection unit 51h and the intermediate frequency Fif.

  FIG. 9 is a diagram showing calculation results of the first spurious frequency and the second spurious frequency. Referring to FIG. 9, the first spurious frequency and the second spurious frequency coincide with each other when m = n = 1 and when m = 3 and n = 2.

  When m = n = 1, the carrier frequency is correctly displayed as described with reference to FIG. In this case, Fsig + Fif = Flo, that is, Fif = Flo−Fsig.

  In the case of m = 3 and n = 2, no-input spurious is displayed as described with reference to FIG. In this case, 3Fsig + Fif = 2Flo, that is, Fif = 2Flo−3Fsig. In the case of m = 3 and n = 2, the first spurious frequency (= second spurious frequency) = 2 (0.9493 + 4.4314). In this way, the coincidence detection unit 51h detects the first spurious frequency (= second spurious frequency) when the first spurious frequency and the second spurious frequency coincide. That is, m and n are set as appropriate, and n · Flo when m · Fsig + Fif = n · Flo is established within a range of values that Flo can take is obtained.

  The spurious frequency determination unit 51i divides the detection result of the coincidence detection unit 51h by n (= 2) to obtain Flo = 0.9493 + 4.4314. Then, Fif (= 4.4314) is subtracted from Flo to obtain spurious frequency = 0.9493 GHz.

  Returning to FIG. 5, the non-input spurious recording unit 52 records the spurious frequency generated by the non-input spurious 2 c calculated by the spurious frequency determination unit 51 i of the non-input spurious calculation unit 51.

The first local frequency sweep instruction unit 54 controls the first local oscillator 12 to sweep the frequency Flo of the first local signal Lo. That is, the frequency Flo is changed from 4.4314 GHz to 7.9314 (= 4.4314 + 3.5) GHz. However, the frequency Flo is 0.9493 corresponding to the spurious frequency.
+ If the value is 4.4314 GHz, the no-input spurious 2c is generated. Therefore, instead of the value of 0.9493 + 4.4314 GHz, a value obtained by adding a predetermined shift value thereto is used as the frequency Flo. As a result, the frequency Flo can be prevented from becoming a spurious frequency corresponding value.

  The shift value recording unit 56 records a predetermined shift value. For example, the predetermined shift value is 60 MHz.

  The second local frequency change instructing unit 58 controls the second local oscillator 22 when the first local frequency sweep instructing unit 54 uses a value obtained by adding a predetermined shift value as the frequency Flo. It is assumed that the signal frequency is obtained by subtracting a predetermined shift value from a predetermined frequency (4.01 GHz in the present embodiment).

  When the first local frequency sweep instruction unit 54 uses a value obtained by adding a predetermined shift value as the frequency Flo, if the frequency of the second local signal remains 4.01 GHz, the signal output from the second multiplier 24 Is reduced by a predetermined shift value.

  However, if the frequency of the second local signal is obtained by subtracting a predetermined shift value from a predetermined frequency (4.01 GHz in this embodiment), the first local frequency sweep instruction unit 54 adds the predetermined shift value. Even when this value is used as the frequency Flo, the frequency of the signal output from the second multiplier 24 can be maintained at 421.4 MHz.

  Next, the operation of the embodiment of the present invention will be described with reference to the flowcharts of FIGS.

  FIG. 10 is a flowchart showing the operation of the embodiment of the present invention. First, the carrier frequency of the signal to be measured is measured by the spectrum analyzer 1 (S10).

That is, the signal mixing device 4 mixes the RF signal with the first local signal, the second local signal, and the third local signal to obtain a signal having a low frequency that allows A / D conversion. The frequency Flo of the first local signal is set from 4.4314 GHz to 7.9314 GHz (=
Change to 4.4314 + 3.5).

  Then, the analog signal output from the signal mixing device 4 is converted into a digital signal by the A / D converter 42. The analysis unit 44 analyzes the measurement target signal based on the digital signal. For example, the relationship between frequency and power is obtained. Finally, the display 46 displays the analysis result (for example, the relationship between frequency and power) by the analysis unit 44. This display result is as shown in FIG. 3, and it can be seen that the carrier frequency is 2.11 GHz.

  Next, the user of the spectrum analyzer 1 inputs the carrier frequency of the measurement target signal and the display range of the frequency via the user interface 51a (S12). For example, the carrier frequency is 2.11 GHz and the frequency display range is 0 to 3.5 GHz. The carrier frequency is recorded in the carrier frequency recording unit 51b, and the display range of the frequency is recorded in the display range recording unit 51g.

  Next, the frequency at which the non-input spurious 2c is generated (the non-input spurious frequency) is calculated by the non-input spurious calculator 51 (S14). That is, the first spurious frequency generation unit 51d calculates the first spurious frequency = m · Fsig + Fif (m is a positive integer). The second spurious frequency generation unit 51f calculates the second spurious frequency = n · Flo (n is a positive integer). Then, the coincidence detection unit 51h appropriately sets m and n, and obtains n · Flo when m · Fsig + Fif = n · Flo is established within a range of values that Flo can take. For example, m = 3, n = 2, and n · Flo = 10.7614 GHz. Finally, the spurious frequency determination unit 51i divides n · Flo obtained by the coincidence detection unit 51h by n and subtracts Fif to obtain spurious frequency = 0.9493 GHz.

  The calculated no-input spurious frequency is recorded in the no-input spurious recording unit 52. Then, the frequency spectrum of the signal to be measured is again measured by the spectrum analyzer 1 (S16). At this time, the non-input spurious 2c shown in FIG. 3 is not displayed, but is correctly displayed as shown in FIG.

  FIG. 11 is a flowchart showing the operation of the spectrum analyzer 1 in the re-measurement (S16). First, the first local frequency sweep instruction unit 54 sets the frequency Flo of the first local signal Lo to an initial value (4.4314 GHz) (S161). Then, the frequency Flo is increased by a predetermined step (S162). Here, if the frequency Flo reaches the final value of 7.9314 (= 4.4314 + 3.5) GHz (S163, Yes), the process ends.

  If the frequency Flo does not reach the final value (S163, No), the first local frequency sweep instruction unit 54 determines whether or not the frequency Flo corresponds to the non-input spurious frequency recorded in the non-input spurious recording unit 52. (S164). If the frequency Flo does not correspond to the no-input spurious frequency (S164, No), the power is measured (S168).

  That is, the signal mixing device 4 mixes the RF signal with the first local signal, the second local signal, and the third local signal to obtain a signal having a low frequency that allows A / D conversion. This signal is converted into a digital signal by the A / D converter 42 and then the relationship between the frequency and the power is obtained by the analysis unit 44 and displayed on the display 46.

If the frequency Flo corresponds to the no-input spurious frequency (S164, Yes), a predetermined shift value (60 MHz) recorded in the shift value recording unit 56 is added to obtain the frequency Flo (S165). For example, if the no-input spurious frequency is 0.9493 GHz, the corresponding frequency Flo is 0.9493 + 4.4314 GHz. Therefore, as a result of increasing the frequency Flo by a predetermined step (S162), the frequency Flo is 0.9493 +
If it is 4.4314 GHz, the frequency Flo is 0.9493 + 4.4314 GHz + 60 MHz. Thereby, it can prevent that the no-input spurious 2c generate | occur | produces.

  Next, the second local frequency change instruction unit 58 controls the second local oscillator 22 to change the frequency of the second local signal from a predetermined frequency (4.01 GHz in this embodiment) to a predetermined shift value (60 MHz). ) Is reduced (S166). Thereby, the frequency of the signal output from the second multiplier 24 can be kept at 421.4 MHz.

  Then, power is measured (S168). Thereafter, the process returns to the step of increasing the frequency Flo by a predetermined step (S162).

  According to the embodiment of the present invention, the coincidence detection unit 51h appropriately sets m and n, and calculates n · Flo when m · Fsig + Fif = n · Flo is satisfied within the range of values that Flo can take. Ask. The spurious frequency determination unit 51i can determine the spurious frequency by subtracting Fif from Flo at this time.

  Moreover, the spurious frequency + Fif + predetermined shift value (instead of the spurious frequency + Fif) is set so that the frequency Flo of the first local signal Lo does not become the spurious frequency + Fif (= 4.4314 GHz). 60MHz) is Flo. Thereby, generation | occurrence | production of the no-input spurious 2c can be prevented.

  Furthermore, instead of the spurious frequency + Fif, when the spurious frequency + Fif + a predetermined shift value (60 MHz) is the frequency Flo, the frequency of the second local signal is determined from the predetermined frequency (4.01 GHz in this embodiment). By subtracting this shift value (60 MHz), the frequency of the signal output from the second multiplier 24 can be maintained at 421.4 MHz.

  Moreover, said embodiment is realizable as follows. A program for realizing each of the above-described parts (for example, the local frequency control unit 50) was recorded on a media reading device of a computer equipped with a CPU, hard disk, and media (floppy (registered trademark) disk, CD-ROM, etc.) reading device. Read the media and install it on the hard disk. Such a method can also realize the above functions.

It is a block diagram which shows the structure of the spectrum analyzer 1 concerning embodiment of this invention. It is a figure which shows an example of the frequency spectrum of a measuring object signal. It is a figure which shows an example of the display mode of the display. It is a figure for demonstrating the frequency component of RF signal from which the analysis part 44 calculates | requires power, A carrier signal (FIG. 4 (a)) and a no-input spurious (FIG.4 (b)) are shown. 3 is a functional block diagram showing a configuration of a local frequency control unit 50. FIG. 3 is a functional block diagram showing a configuration of a no-input spurious calculation unit 51. FIG. It is a figure which shows the calculation result of a 1st spurious frequency. It is a figure which shows the calculation result of a 2nd spurious frequency. It is the figure which displayed the calculation result of the 1st spurious frequency and the 2nd spurious frequency. It is a flowchart which shows operation | movement of embodiment of this invention. It is a flowchart which shows operation | movement of the spectrum analyzer 1 in remeasurement (S16).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spectrum analyzer 4 Signal mixing apparatus 12 1st local oscillator 14 1st multiplier (1st mixing means)
16 Band pass filter 22 Second local oscillator 24 Second multiplier (second mixing means)
42 A / D converter 44 Analysis unit 46 Display (display means)
50 local frequency control unit 51d first spurious frequency generation unit 51f second spurious frequency generation unit 51h coincidence detection unit 51i spurious frequency determination unit 52 no-input spurious recording unit 54 first local frequency sweep instruction unit (first local frequency change means)
56 shift value recording unit 58 second local frequency change instruction unit (second local frequency changing means)

Claims (10)

First local signal generating means for generating a first local signal;
A first mixing means for mixing the signal to be measured and the first local signal and outputting a signal of an intermediate frequency;
Avoiding a spurious frequency corresponding value corresponding to the spurious frequency generated by the first mixing means, first local frequency changing means for changing the frequency of the first local signal;
A signal mixing device comprising :
The first local frequency changing means, instead of the spurious frequency corresponding value, a value obtained by adding a predetermined shift value to the spurious frequency corresponding value as the frequency of the first local signal ,
The signal mixing device further comprises:
Second local signal generation means for generating a second local signal of a predetermined frequency;
Second mixing means for mixing the output of the first mixing means and the second local signal;
When the first local frequency changing means uses the value obtained by adding the predetermined shift value to the spurious frequency corresponding value instead of the spurious frequency corresponding value as the frequency of the first local signal, A second local frequency changing means for subtracting the predetermined shift value from the predetermined frequency for the frequency of the signal;
A signal mixing device. First local signal generating means for generating a first local signal;
A first mixing means for mixing the signal to be measured and the first local signal and outputting a signal of an intermediate frequency;
Avoiding a spurious frequency corresponding value corresponding to the spurious frequency generated by the first mixing means, first local frequency changing means for changing the frequency of the first local signal;
With
The spurious frequency is determined based on values taken by a carrier frequency of the measurement target signal, the intermediate frequency, and the frequency of the first local signal.
Signal mixing device. The signal mixing device according to claim 2 ,
First spurious frequency generation means for generating a value obtained by adding the intermediate frequency to the carrier frequency of the measurement target signal multiplied by a positive integer multiple;
Second spurious frequency generation means for generating a value obtained by multiplying a value taken by the frequency of the first local signal by a positive integer,
A coincidence detection unit for detecting the generation result when the generation results of the first spurious frequency generation unit and the second spurious frequency generation unit coincide;
Spurious frequency determining means for determining the spurious frequency based on the detection result of the coincidence detecting means and the intermediate frequency;
A signal mixing device. A signal mixing device according to any one of claims 1 to 3 ;
Analyzing means for analyzing the signal to be measured based on the output of the signal mixing device;
Display means for displaying the analysis result of the analysis means;
Spectrum analyzer with A first local signal generating step in which the first local signal generating means generates the first local signal;
A first mixing unit that mixes the signal to be measured and the first local signal and outputs an intermediate frequency signal; and
A first local frequency changing step in which the first local frequency changing means changes the frequency of the first local signal while avoiding a spurious frequency corresponding value corresponding to the spurious frequency generated by the first mixing means;
A signal mixing method comprising:
The first local frequency changing means, instead of the spurious frequency corresponding value, a value obtained by adding a predetermined shift value to the spurious frequency corresponding value as the frequency of the first local signal ,
The signal mixing method further comprises:
A second local signal generating means for generating a second local signal having a predetermined frequency;
A second mixing step in which the second mixing means mixes the output of the first mixing means and the second local signal;
The second local frequency changing means, wherein the first local frequency changing means adds a value obtained by adding the predetermined shift value to the spurious frequency corresponding value instead of the spurious frequency corresponding value as the frequency of the first local signal. A second local frequency changing step in which the frequency of the second local signal is obtained by subtracting the predetermined shift value from the predetermined frequency;
A signal mixing method comprising: A first local signal generating step in which the first local signal generating means generates the first local signal;
A first mixing unit that mixes the signal to be measured and the first local signal and outputs an intermediate frequency signal; and
A first local frequency changing step in which the first local frequency changing means changes the frequency of the first local signal while avoiding a spurious frequency corresponding value corresponding to the spurious frequency generated by the first mixing means;
With
The spurious frequency is determined based on values taken by a carrier frequency of the measurement target signal, the intermediate frequency, and the frequency of the first local signal.
Signal mixing method. First local signal generating means for generating a first local signal, first mixing means for mixing the measurement target signal and the first local signal and outputting an intermediate frequency signal, and a second local signal having a predetermined frequency A program for causing a computer to execute signal mixing processing in a signal mixing device having second local signal generating means for generating a signal, and second mixing means for mixing the output of the first mixing means and the second local signal Because
A first local frequency changing process for changing a frequency of the first local signal by avoiding a spurious frequency corresponding value corresponding to a spurious frequency generated by the first mixing unit;
A program for causing a computer to execute the,
In the first local frequency changing process, instead of the spurious frequency corresponding value, a value obtained by adding a predetermined shift value to the spurious frequency corresponding value is set as the frequency of the first local signal ,
When the first local frequency changing process uses the value obtained by adding the predetermined shift value to the spurious frequency corresponding value instead of the spurious frequency corresponding value as the frequency of the first local signal, A second local frequency change process in which the frequency of the signal is obtained by subtracting the predetermined shift value from the predetermined frequency;
A program that causes a computer to execute further . Signal mixing in a signal mixing apparatus comprising: first local signal generating means for generating a first local signal; and first mixing means for mixing the measurement target signal and the first local signal and outputting a signal having an intermediate frequency. A program for causing a computer to execute processing,
A first local frequency changing process for changing a frequency of the first local signal by avoiding a spurious frequency corresponding value corresponding to a spurious frequency generated by the first mixing unit;
A program for causing a computer to execute the,
The spurious frequency is determined based on values taken by a carrier frequency of the measurement target signal, the intermediate frequency, and the frequency of the first local signal.
Program . First local signal generating means for generating a first local signal, first mixing means for mixing the measurement target signal and the first local signal and outputting an intermediate frequency signal, and a second local signal having a predetermined frequency A program for causing a computer to execute signal mixing processing in a signal mixing device having second local signal generating means for generating a signal, and second mixing means for mixing the output of the first mixing means and the second local signal A computer-readable recording medium that records
A first local frequency changing process for changing a frequency of the first local signal by avoiding a spurious frequency corresponding value corresponding to a spurious frequency generated by the first mixing unit;
A recording medium readable by the recording a computer program for causing a computer to execute the,
In the first local frequency changing process, instead of the spurious frequency corresponding value, a value obtained by adding a predetermined shift value to the spurious frequency corresponding value is set as the frequency of the first local signal ,
When the first local frequency changing process uses the value obtained by adding the predetermined shift value to the spurious frequency corresponding value instead of the spurious frequency corresponding value as the frequency of the first local signal, A second local frequency change process in which the frequency of the signal is obtained by subtracting the predetermined shift value from the predetermined frequency;
A computer-readable recording medium having recorded thereon a program for causing the computer to execute . Signal mixing in a signal mixing apparatus comprising: first local signal generating means for generating a first local signal; and first mixing means for mixing the measurement target signal and the first local signal and outputting a signal having an intermediate frequency. A computer-readable recording medium storing a program for causing a computer to execute processing,
A first local frequency changing process for changing a frequency of the first local signal by avoiding a spurious frequency corresponding value corresponding to a spurious frequency generated by the first mixing unit;
A recording medium readable by the recording a computer program for causing a computer to execute the,
The spurious frequency is determined based on values taken by a carrier frequency of the measurement target signal, the intermediate frequency, and the frequency of the first local signal.
Recording medium .

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