JP6545221B2 - Spectrum analyzer and signal analysis method - Google Patents

Description

The present invention relates to a spectrum analyzer and a signal analysis method, in particular, it relates away Baek tram The Analysis The及 beauty signal analysis methods to display the time-series waveform and converts an analog signal to be measured into digital data.

  A signal analyzer such as a signal analyzer or spectrum analyzer that receives an RF signal output from a device under test (DUT) as a signal to be measured and performs analysis processing on the signal to be measured is conventionally known. ing.

  A signal analysis apparatus converts a carrier frequency of an input signal under test into an intermediate frequency, and an intermediate frequency (IF) filter which passes only a signal component of a predetermined passband including the intermediate frequency of the intermediate frequency signal. And an A / D converter (ADC) for sampling at a predetermined sampling rate the measured signal frequency-converted by the frequency converter and converting it into digital data.

  Furthermore, the signal analysis device digitally processes the digital data output from the ADC to generate image information such as an amplitude waveform or a frequency spectrum waveform of the signal to be measured, and displays the image information on the display device. It is configured to let you

  Some signal analyzers have a trigger function for the user to start measurement at a desired timing. Some trigger functions include “video trigger” that triggers at timing when the level of the video signal which is a waveform signal displayed on the display device exceeds (or falls below) a certain threshold, the level of the wide passband IF signal "Wide IF video trigger" triggered at timing when the threshold value is exceeded (or below), external trigger triggered at timing of rising edge and / or falling edge of trigger signal input from outside "and so on.

  As a signal analysis device having a trigger function, a device that demodulates a digitally modulated signal to generate a serial data string and generates a trigger signal based on this serial data string has already been proposed (for example, Patent Document) 1).

Patent No. 3424996

  However, in the conventional signal analysis apparatus as disclosed in Patent Document 1, the converted digital signal differs from the actual data due to a conversion error in A / D conversion processing when the trigger signal is generated. Error data may be included. Therefore, when this error data exceeds (or falls below) the threshold value, there is a problem that a trigger is triggered at an incorrect timing.

The present invention has been made to solve such conventional problems, and the value of digital data is obtained even when a single conversion error occurs when converting a signal under test into digital data. It is an object of the present invention to provide a spectrum analyzer and a signal analysis method capable of preventing a trigger signal generated in response to generation at an incorrect timing due to a conversion error.

In order to solve the above problems, a spectrum analyzer according to the present invention includes an analog signal processor that performs analog signal processing on a signal under test, which is an RF signal output from a test object, and an ADC. The time-series data generated as a time-series data generation unit that converts the measured signal subjected to analog signal processing by the analog signal processing unit into time-series data as digital data by the ADC is single-shot by the ADC Time series data generation unit which may include error data caused by a conversion error, a buffer memory for temporarily storing the time series data, N continuous time series data (N is 2 or more) A threshold determination unit that determines whether or not a predetermined threshold has been exceeded, and the threshold determination unit determines N consecutive pieces of time series data. The trigger signal generation unit that generates a trigger signal at timing determined to exceed the threshold of and the time-series data stored in the buffer memory are read out and displayed on a display unit according to the timing of the trigger signal. A control unit that performs control, and an operation unit that allows the user to set at least the value of N. The control unit changes the setting of the value of N based on an operation on the operation unit. The time series data is displayed without including error data caused by the one-time conversion error by the ADC.

With this configuration, the spectrum analyzer according to the present invention adds the number of time series data exceeding the threshold to the determination criterion even if a single conversion error occurs when converting the signal to be measured to digital data. Thus, it is possible to prevent a trigger signal generated in accordance with the value of digital data from being generated at an incorrect timing due to a conversion error.

Further, in the spectrum analyzer according to the present invention, the analog signal processing unit includes: a local oscillator that oscillates a local signal; and a sweep unit that sweeps the frequency of the local signal oscillated from the local oscillator over a predetermined sweep period; A frequency mixer for mixing and frequency-converting the local signal and the signal to be measured which are frequency-swept by the sweep unit, and filtering the signal to be measured which is frequency-converted by the frequency mixer to be an intermediate frequency signal It may have an IF filter to output, and a detector that outputs a signal obtained by detecting the intermediate frequency signal for the predetermined sweep period to the time series data generation unit .

Further, in the spectrum analyzer according to the present invention, the time-series data may indicate frequency characteristics of the amplitude of the signal under measurement.

With this configuration, the spectrum analyzer according to the present invention can measure the measured signal without including error data due to the conversion error, even if a single conversion error occurs when converting the measured signal into digital data. The frequency characteristics of the amplitude can be displayed.

Further, in the spectrum analyzer according to the present invention, the control unit is configured to, when it is determined by the threshold determination unit that N pieces of time series data continuously exceed a predetermined threshold, the N pieces of time series The display unit may be configured to display an arbitrary number of pieces of time-series data continuous from the first piece of data.

With this configuration, the spectrum analyzer according to the present invention adds the number of time series data exceeding the threshold to the determination criterion even if a single conversion error occurs when converting the signal to be measured to digital data. Thus, it is possible to display time-series data over a desired display time range or display frequency range that includes time-series data actually exceeding the threshold.

Further, in the spectrum analyzer according to the present invention, the control unit is configured to, when it is determined by the threshold determination unit that N pieces of time series data continuously exceed a predetermined threshold, the N pieces of time series The display unit displays an arbitrary number of the time-series data continuous from the first one of data and an arbitrary number of the time-series data continuous before the first one of the N time-series data It may be configured to

With this configuration, the spectrum analyzer according to the present invention adds the number of time series data exceeding the threshold to the determination criterion even if a single conversion error occurs when converting the signal to be measured to digital data. Thus, it is possible to display time-series data over a desired display time range or display frequency range that includes time-series data actually exceeding the threshold.

In the signal analysis method according to the present invention, an analog signal processing step of performing analog signal processing on a signal under test, which is an RF signal output from a test object, and analog signal processing in the analog signal processing step In the time-series data generation step of converting the measured signal into time-series data as digital data by the ADC, the time-series data generated may include error data due to a single conversion error by the ADC. Whether there is a certain time series data generation step, a step of temporarily storing the time series data in a buffer memory, and N consecutive time series data (N is an integer of 2 or more) have exceeded a predetermined threshold value In the threshold determination step of determining whether or not N pieces of time series data continuously exceed the predetermined threshold in the threshold determination step A step of generating a trigger signal at a determined timing, and a control step of performing control of reading out the time-series data stored in the buffer memory and displaying it on a display unit according to the timing of the trigger signal And changing the setting of the value of N based on an operation on the operation unit that allows the user to set at least the value of N, and including error data due to the one-time conversion error by the ADC Instead, the time series data is displayed.

  With this configuration, the signal analysis method according to the present invention uses the number of time series data exceeding the threshold as a determination criterion even if a single conversion error occurs when converting the signal to be measured to digital data. By adding, it is possible to prevent the trigger signal generated according to the value of the digital data from being generated at the wrong timing due to the conversion error.

  According to the present invention, even if a single conversion error occurs when converting a signal under test to digital data, the trigger signal generated according to the value of digital data is at the wrong timing due to the conversion error. It is an object of the present invention to provide a signal analysis device and a signal analysis method that can be prevented from being generated.

It is a block diagram showing composition of a signal analysis device concerning a 1st embodiment of the present invention. (A) is a graph for demonstrating the display time range in the display part with which the signal analyzer which concerns on the 1st Embodiment of this invention is equipped, (b) is a signal analysis which concerns on the 1st Embodiment of this invention It is a graph for demonstrating the other example of the display time range in the display part with which an apparatus is provided. It is a block diagram which shows the structure of the signal-analysis apparatus based on the 2nd Embodiment of this invention. (A) is a graph for demonstrating the display frequency range in the display part with which the signal analyzer which concerns on the 2nd Embodiment of this invention is provided, (b) is the signal analysis which concerns on the 2nd Embodiment of this invention It is a graph for demonstrating the other example of the display frequency range in the display part with which an apparatus is provided. It is a flowchart for demonstrating the process of the signal-analysis method by the signal-analysis apparatus based on embodiment of this invention. It is a flowchart for demonstrating in detail the time-sequential data production | generation process in the flowchart of FIG.

  Hereinafter, a signal analysis device and a signal analysis method according to an embodiment of the present invention will be described using the drawings.

First Embodiment
As shown in FIG. 1, the signal analysis apparatus 100 according to the first embodiment of the present invention includes an analog signal processing unit 10, an ADC 20, a digital signal processing unit 30, an operation unit 40, and a display unit 50. The controller 60 is provided to analyze the measured signal S output from the DUT 1.

  The DUT 1 and the analog signal processing unit 10 may be connected by a coaxial cable, or may be connected by wireless communication.

  The DUT 1 is, for example, a wireless terminal device or a base station having a wireless communication antenna and an RF circuit. The communication standard of the DUT 1 includes cellular (LTE, LTE-A, W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, 1xEV-DO, TD-SCDMA, etc.), wireless LAN (IEEE 802.11b / g / a / n / ac / ad etc.), Bluetooth (registered trademark), GNSS (GPS, Galileo, GLONASS, BeiDou etc.), FM, and digital broadcasting (DVB-H, ISDB-T etc.).

  The analog signal processing unit 10 performs analog signal processing such as frequency conversion on the signal to be measured S output from the DUT 1, and includes an attenuator (ATT) 11, a local oscillator 12, and a frequency mixer 13. The amplifier 14, the IF filter 15, and the IF amplifier 16 are included.

  The ATT 11 is an electronic component that has a resistance inside and that attenuates the high frequency measured signal S from the DUT 1 to a signal level that can be processed by the digital signal processing unit 30 in the subsequent stage, and does not change the impedance.

  The local oscillator 12 generates, as a local signal, a sine wave having a frequency higher or lower than that of the original signal S to be measured by the value of the frequency to be converted. The frequency of the local signal oscillated from the local oscillator 12 is set by the control unit 60 according to the desired analysis band.

The frequency mixer 13 mixes the measured signal _S of the frequency f _S attenuated by the ATT 11 with the local signal of the frequency f _L oscillated from the local oscillator 12 and generates frequency components of the sum and difference of the two signals. To generate an output signal.

  The amplifier 14 amplifies the output signal from the frequency mixer 13 and outputs the amplified signal to the IF filter 15.

The IF filter 15 is configured by an analog band pass filter or the like, and is configured to filter an output signal from the frequency mixer 13. The IF filter 15 operates when the intermediate frequency signal of the intermediate frequency | f _L −f _S | or f _L + f _{S obtained} by mixing the measured signal S and the local signal by the frequency mixer 13 is within a predetermined frequency range. , The intermediate frequency signal amplified by the amplifier 14 is output.

  The IF amplifier 16 controls the amplitude level of the signal output from the IF filter 15 according to the set gain. Thus, when the gain of the IF amplifier 16 is changed, the amplitude level of the signal (amplitude waveform) to be graphed and displayed on the display unit 50 described later can be changed.

  The ADC 20 samples the signal output from the IF amplifier 16 at a predetermined sampling rate and converts it into digital data. The ADC 20 outputs this digital data to the digital signal processing unit 30 in order to display a predetermined graph on the display unit 50.

  The digital signal processing unit 30 includes, for example, an orthogonal demodulation unit 31 a, an analysis processing unit 31 b, a buffer memory 32, a threshold value determination unit 33, and a trigger signal generation unit 34.

  Here, the ADC 20, the orthogonal demodulation unit 31a, and the analysis processing unit 31b constitute a time-series data generation unit 31, and time-series data of the signal to be measured S subjected to analog signal processing by the analog signal processing unit 10 as digital data. It is supposed to be converted to

  The orthogonal demodulation unit 31a orthogonally demodulates the digital data output from the ADC 20 to generate orthogonal signals I (t) and Q (t) orthogonal to each other. As the orthogonal demodulation unit 31a, for example, an orthogonal distributor using Hilbert transform can be used.

  The analysis processing unit 31 b is configured to perform digital signal processing such as digital filter processing on the quadrature signals I (t) and Q (t) output from the quadrature demodulation unit 31 a. Furthermore, the analysis processing unit 31 b uses time-series data indicating time changes such as the amplitude, phase, and frequency of the signal to be measured S using the quadrature signals I (t) and Q (t) subjected to the above digital signal processing. It is designed to output data.

  The buffer memory 32 is configured to temporarily store time-series data output from the time-series data generation unit 31.

  The threshold determination unit 33 determines whether N pieces of time-series data output from the time-series data generation unit 31 continuously exceed a predetermined threshold Th (N is an integer of 2 or more). There is.

  The trigger signal generation unit 34 generates a trigger signal at a timing when the threshold determination unit 33 determines that N pieces of time series data continuously exceed the predetermined threshold Th.

  The control unit 60 is configured of, for example, a microcomputer including a CPU, a ROM that configures the storage unit 61, a RAM, a HDD, and the like, a personal computer, and the like, and controls the operation of each unit that configures the signal analysis device 100.

  The digital signal processing unit 30 may be configured as a digital circuit such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), or configured as software by execution of a predetermined program by the control unit 60. Is possible. Alternatively, the digital signal processing unit 30 can be configured by appropriately combining hardware processing by a digital circuit and software processing by a predetermined program.

  Control unit 60 performs processing for reading time-series data stored in buffer memory 32 according to the timing of the trigger signal output from trigger signal generation unit 34, and storing the read time-series data in storage unit 61. At the same time, a video signal for performing control to display the read time series data on the display unit 50 is output. Here, the video signal is a waveform signal displayed on the display unit 50.

  The display unit 50 displays time-series data stored in the storage unit 61 with time on the horizontal axis and amplitude, phase, frequency, etc. on the vertical axis according to the video signal output from the control unit 60. ing.

  FIGS. 2A and 2B are graphs schematically showing an example of the analysis result by the analysis processing unit 31b, where the horizontal axis indicates time, and the vertical axis indicates amplitude. At time t0, error data exceeding the threshold Th due to the conversion error of the ADC 20 is observed. Usually, a plurality of such error data does not appear continuously. On the other hand, after time t1, N pieces of time-series data exceeding the threshold value Th appear in succession. Assuming that N = 4, the trigger signal is output from the trigger signal generation unit 34 at the timing of time t2.

  For example, when it is determined by the threshold value determination unit 33 that N pieces of time series data continuously exceed the predetermined threshold Th, the control unit 60 determines an arbitrary number of consecutive ones of the N pieces of time series data. The display unit 50 is configured to display time-series data of M in number. In FIG. 2A, time t3 is the time of the M-th time-series data continuous from the first one of the N time-series data.

  In this case, the buffer memory 32 needs to be configured to be able to store at least N time-series data. In the example of FIG. 2A, time-series data covering the display time range Δt from time t1 to time t3 is displayed on the display unit 50.

  Alternatively, when it is determined by the threshold determination unit 33 that N pieces of time series data continuously exceed the predetermined threshold Th, the control unit 60 continues to the first or subsequent ones of the N pieces of time series data. The display unit 50 may display an arbitrary number M of time-series data and an arbitrary number L of time-series data continuous before the first of N pieces of time-series data.

  In FIG. 2B, time t4 is the time of the L-th time-series data continuous to the first one of the N time-series data. Further, time t5 is the time of the M-th time-series data continuous from the first one of the N time-series data.

  In this case, the buffer memory 32 needs to be configured to be able to store at least N + L−1 pieces of time-series data. In the example of FIG. 2B, time-series data covering the display time range Δt from time t4 to time t5 is displayed on the display unit 50.

  Each value of the threshold Th and the display time range Δt, N, M, L can be set by the operation of the operation unit 40 by the user.

  As described above, in the signal analysis device 100 according to the present embodiment, even when a single conversion error occurs when converting the signal to be measured S into digital data, time-series data exceeding the threshold Th It is possible to prevent the trigger signal generated in accordance with the value of the digital data from being generated at the wrong timing due to the conversion error by adding the number of pixels to the determination standard.

  Further, in the signal analysis device 100 according to the present embodiment, even if a single conversion error occurs when converting the signal to be measured S to digital data, the measurement is performed without including error data due to the conversion error. The time variation of the amplitude of the signal S can be displayed.

  In addition, the signal analysis device 100 according to the present embodiment determines the number of time series data exceeding the threshold Th even when a single conversion error occurs when converting the signal to be measured S into digital data. By adding to the reference, it is possible to display time-series data over a desired display time range Δt including time-series data actually exceeding the threshold Th.

Second Embodiment
Subsequently, a signal analysis device 200 according to a second embodiment of the present invention will be described with reference to the drawings. The same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be appropriately omitted. The description of the same operation as that of the first embodiment will also be omitted as appropriate.

  As shown in FIG. 3, the signal analysis device 200 according to the second embodiment of the present invention includes an analog signal processing unit 70, an ADC 20, a digital signal processing unit 80, an operation unit 40, and a display unit 50. The controller 60 is provided to analyze the measured signal S output from the DUT 1.

  The analog signal processing unit 70 includes an attenuator (ATT) 11, a local oscillator 12, a frequency mixer 13, an amplifier 14, an IF filter 15, an IF amplifier 16, a detector 17, and a video filter 18. An amplifier 19 and a sweep unit 21 are provided.

In the present embodiment, the frequency f _{L of the} local signal oscillated from the local oscillator 12 is swept over a predetermined frequency range by the sweep ramp signal output from the sweep unit 21.

  In the case of the present embodiment, the IF filter 15 is configured by an RBW (Resolution Band Width) filter and a logarithmic amplifier (log amplifier) configured by an analog band pass filter or the like.

  Since the logarithmic amplifier included in the IF filter 15 is an amplifier that outputs an amplified signal corresponding to the logarithm of the signal to be measured S, when the signal to be measured S is allowed to pass through the IF filter 15, large dynamic It can be handled collectively as a signal of range.

  Therefore, the signal analysis device 200 can perform display corresponding to decibels using a linear display device.

  In the present embodiment, the output signal from the frequency mixer 13 changes in synchronization with the sweep operation. Therefore, according to the change, the signal which is a time-series waveform in each frequency component of the signal S under test which is converted into the intermediate frequency signal over time within one sweep time (sweep period) by the IF filter 15 It is extracted.

  Further, in the present embodiment, when the gain of the IF amplifier 16 is changed, the amplitude level of the signal (frequency spectrum waveform) to be graphed and displayed on the display unit 50 can be changed.

  The detector 17 is, for example, an envelope detector, and is configured to convert a signal extracted by the IF filter 15 and whose amplitude level has been changed by the IF amplifier 16 into a direct current.

  The detector 17 detects the peak value of each time axis position in the analog frequency spectrum waveform output from the IF amplifier 16, and outputs the frequency spectrum waveform in the state of envelope detection.

  The signal detected within the sweep period by the detector 17 indicates the magnitude of the time series waveform at the swept frequency. In this case, when the display unit 50 displays a graph with the horizontal axis as frequency and the vertical axis as amplitude level (decibel), the displayed graph becomes a frequency spectrum waveform.

  The video filter 18 is a video bandwidth (VBW) filter and functions as a filter not for the spectrum of the signal detected by the detector 17 but for time variations of the detected signal. With this function, the video filter 18 obtains the intensity of the signal to be measured S for each frequency, and outputs a signal for displaying a frequency spectrum waveform.

  The amplifier 19 amplifies the signal input from the video filter 18 and outputs the amplified signal to the ADC 20.

  The ADC 20 constitutes a time-series data generation unit 31, samples the signal output from the amplifier 19 at a predetermined sampling rate, and converts the signal into time-series data as digital data. The time-series data here indicates the frequency characteristic of the amplitude of the signal to be measured S. The ADC 20 outputs the time-series data to the digital signal processing unit 80 in order to display a predetermined graph on the display unit 50.

The sweep unit 21 generates a sweep ramp signal for sweeping the frequency f _{L of the} local signal oscillated from the local oscillator 12 over a predetermined frequency range, and generates the sweep ramp signal according to the set sweep time. Control.

  The ADC 22 converts the sweep ramp signal generated in the sweep unit 21 into digital data and outputs the digital data to the control unit 60.

  Thereby, the control unit 60 controls a sweep period or the like for generating a sweep ramp signal in the sweep unit 21 based on the digital data from the ADC 22.

  In the present embodiment, the display unit 50 displays time-series data stored in the storage unit 61 with the horizontal axis as frequency and the vertical axis as amplitude according to the video signal output from the control unit 60. It has become.

  FIGS. 4A and 4B are graphs schematically showing an example of time-series data output from the ADC 20. The horizontal axis represents frequency, and the vertical axis represents amplitude. At the frequency f0, error data exceeding the threshold Th due to the conversion error of the ADC 20 is observed. Usually, a plurality of such error data does not appear continuously. On the other hand, N times of time-series data exceeding the threshold Th appear continuously after the frequency f1. Assuming that N = 4, the trigger signal is output from the trigger signal generation unit 34 at the timing of the frequency f2.

  For example, when it is determined by the threshold value determination unit 33 that N pieces of time series data continuously exceed the predetermined threshold Th, the control unit 60 determines an arbitrary number of consecutive ones of the N pieces of time series data. The display unit 50 is configured to display time-series data of M in number. In FIG. 4A, the frequency f3 is the frequency of the M-th time-series data continuous from the first of the N time-series data.

  In this case, the buffer memory 32 needs to be configured to be able to store at least N time-series data. In the example of FIG. 4A, time-series data covering the display frequency range Δf from the frequency f1 to the frequency f3 is displayed on the display unit 50.

  Alternatively, when it is determined by the threshold determination unit 33 that N pieces of time series data continuously exceed the predetermined threshold Th, the control unit 60 continues to the first or subsequent ones of the N pieces of time series data. The display unit 50 may display an arbitrary number M of time-series data and an arbitrary number L of time-series data continuous before the first of N pieces of time-series data.

  In FIG. 4B, a frequency f4 is a frequency of L-th time-series data continuous before the first of N pieces of time-series data. The frequency f5 is the frequency of the M-th time-series data continuous from the first of the N time-series data.

  In this case, the buffer memory 32 needs to be configured to be able to store at least N + L−1 pieces of time-series data. In the example of FIG. 4B, the time-series data covering the display frequency range Δf from the frequency f4 to the frequency f5 is displayed on the display unit 50.

  The values of the threshold Th and the display frequency ranges Δf, N, M and L can be set by the operation of the operation unit 40 by the user.

  As described above, the signal analysis apparatus 200 according to the present embodiment does not include error data due to a conversion error even when a single conversion error occurs when converting the signal to be measured S into digital data. The frequency characteristic of the amplitude of the signal to be measured S can be displayed.

In addition, the signal analysis device 200 according to the present embodiment determines the number of time series data exceeding the threshold Th even if a single conversion error occurs when converting the signal to be measured S to digital data. By adding to the reference, it is possible to display time-series data over a desired display frequency range Δf including time-series data actually exceeding the threshold Th.
(Signal analysis method)
Hereinafter, an example of the processing of the signal analysis method using the signal analysis devices 100 and 200 according to the first and second embodiments will be described with reference to the flowchart of FIG. 5.

  First, the signal analysis devices 100 and 200 execute time-series data generation processing described later (step S1). The details of this process will be described along the flowchart of FIG. 6 described later.

  Next, the threshold determination unit 33 determines whether N pieces of time-series data obtained in step S1 continuously exceed a predetermined threshold (N is an integer of 2 or more) (threshold determination step S2). . If the determination is negative, the process returns to step S1, and if the determination is affirmative, the process proceeds to step S3.

  Next, the trigger signal generation unit 34 generates a trigger signal at the timing when it is determined that N pieces of time series data continuously exceed the predetermined threshold in the threshold determination step S2 (trigger signal generation step S3).

  Next, the control unit 60 reads out the time-series data stored in the buffer memory 32 according to the timing of the trigger signal and causes the display unit 50 to display the time-series data (control step S4).

  Next, control unit 60 determines whether or not all the time series data included in display time range Δt (or display frequency range Δf) are displayed on display unit 50 (step S5). In the case of a negative determination, the process proceeds to step S6, and in the case of a positive determination, the process ends.

  Next, the signal analysis devices 100 and 200 execute time-series data generation processing described later (step S6). The details of this process will be described along the flowchart of FIG. 6 described later.

  Hereinafter, the time-series data generation process of steps S1 and S6 will be described with reference to the flowchart of FIG.

  First, the analog signal processing unit 10 performs analog signal processing such as frequency conversion on the signal to be measured S output from the DUT 1 (analog signal processing step S11).

  Next, the time series data generation unit 31 converts the measured signal S subjected to the analog signal processing in the analog signal processing step S11 into time series data as digital data (time series data generation step S12).

  Next, the buffer memory 32 temporarily stores the time series data generated in the time series data generation step S12 (S13).

1 DUT
10, 70 Analog signal processing unit 20 ADC
30, 80 Digital Signal Processing Unit 31 Time Series Data Generation Unit 32 Buffer Memory 33 Threshold Determination Unit 34 Trigger Signal Generation Unit 50 Display Unit 60 Control Unit 61 Storage Unit 100, 200 Signal Analysis Device

Claims (6)

An analog signal processing unit (10, 70) that performs analog signal processing on a signal under test (S) that is an RF signal output from a test object;
Time-series data generation unit (31) including an ADC (20) and converting the measured signal subjected to analog signal processing by the analog signal processing unit into time-series data as digital data by the ADC The time series data generation unit (31), which may include error data caused by a single conversion error by the ADC;
A buffer memory (32) for temporarily storing the time series data;
A threshold determination unit (33) that determines whether or not N pieces of time series data continuously exceed a predetermined threshold (N is an integer of 2 or more);
A trigger signal generation unit (34) for generating a trigger signal at a timing when it is determined by the threshold determination unit that N pieces of time series data have continuously exceeded a predetermined threshold;
A control unit (60) for performing control to read out the time-series data stored in the buffer memory and display it on a display unit (50) according to the timing of the trigger signal;
An operation unit (40) which allows the user to set at least the value of N ;
The control unit is configured to change the setting of the value of N based on an operation on the operation unit.
A spectrum analyzer which displays the time series data without including error data due to the one-time conversion error by the ADC. The analog signal processing unit
A local oscillator (12) that oscillates a local signal,
A sweep unit (21) for sweeping the frequency of the local signal oscillated from the local oscillator over a predetermined sweep period;
A frequency mixer (13) for mixing and frequency-converting the local signal whose frequency is swept by the sweep unit and the signal to be measured;
An IF filter (15) for filtering the measured signal frequency-converted by the frequency mixer and outputting it as an intermediate frequency signal;
The spectrum analyzer according to claim 1, further comprising: a detector (17) which outputs a signal obtained by detecting the intermediate frequency signal over the predetermined sweep period to the time series data generation unit.   The spectrum analyzer according to claim 1 or 2, wherein the time-series data indicates frequency characteristics of amplitude of the signal under test.   The control unit is configured to, when the threshold determination unit determines that N pieces of time series data continuously exceed a predetermined threshold, any one of the N pieces of time series data continuing from the first one onwards. The spectrum analyzer according to any one of claims 1 to 3, wherein the display unit displays the number of pieces of time-series data.   The control unit is configured to, when the threshold determination unit determines that N pieces of time series data continuously exceed a predetermined threshold, any one of the N pieces of time series data continuing from the first one onwards. The display unit is configured to display the number of the time-series data and an arbitrary number of the time-series data continuous before the first one of the N pieces of the time-series data. The spectrum analyzer according to any one of Items 3. An analog signal processing step (S11) for performing analog signal processing on the signal under test (S) which is an RF signal output from the test object;
The time-series data generated in the time-series data generation step (S12) of converting the measured signal subjected to analog signal processing in the analog signal processing step into time-series data as digital data by the ADC (20) is The time series data generation step (S12) which may include error data caused by a single conversion error by the ADC;
Temporarily storing the time series data in a buffer memory (32);
A threshold determination step (S2) for determining whether or not N pieces of time series data continuously exceed a predetermined threshold (N is an integer of 2 or more);
A trigger signal generation step (S3) of generating a trigger signal at a timing when it is determined in the threshold determination step that N pieces of time series data have continuously exceeded a predetermined threshold;
A control step (S4) for performing control to read out the time-series data stored in the buffer memory and display it on a display unit (50) according to the timing of the trigger signal;
Changing the setting of the value of N based on an operation on the operation unit (40) which allows the user to set at least the value of N.
The signal analysis method which displays the said time-series data, without including the error data resulting from the said one-time conversion error by said ADC.

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