CN110672920A - Spectrum analyzer with temperature compensation function - Google Patents
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Abstract
The invention discloses a spectrum analyzer with temperature compensation function, when needing calibration, the input end of a calibration module is connected with the output end of a tracking source signal generation module through a first switch, to measure the power of the output signal of the tracking source signal generation module, and connect the calibration module with the frequency conversion module through the second switch, the power of the signal in the receiving channel of the spectrum analyzer is measured by a signal processing module connected with a frequency conversion module, the output display power of the spectrum analyzer is compensated by comparing the power difference value in the signal processing module and the calibration module with the preset standard power difference value, and because the tracking source signal generation module can output signals of any frequency point in the maximum frequency measurement range of the spectrum analyzer, the temperature compensation can be carried out on the signal power of any frequency point of the full frequency band.
Description
Technical Field
The invention relates to the technical field of electronic measurement, in particular to a spectrum analyzer with a temperature compensation function.
Background
The spectrum analyzer is an instrument for displaying the spectral characteristics of an input electric signal in a frequency domain, and is mainly used for measuring signal parameters such as signal distortion degree, modulation degree, spectrum purity, frequency stability, intermodulation distortion and the like.
The spectrum analyzer can be converted into intermediate frequency signal through the frequency conversion module after receiving the input signal of input to make things convenient for the analog to digital converter to sample, the link between spectrum analyzer input to the analog to digital converter is called the receiving channel, the power gain of receiving channel can change along with temperature variation, though can calibrate the spectrum analyzer when leaving the factory, nevertheless when its use temperature and leave the factory when calibrating the temperature difference great, the power gain of receiving channel can deviate from the calibration value, lead to its measuring accuracy to worsen.
Disclosure of Invention
The invention mainly solves the technical problem of providing a spectrum analyzer with a full-band temperature compensation function.
According to a first aspect, there is provided in an embodiment a spectrum analyzer with temperature compensation, comprising: the tracking source signal generating module is connected with the frequency conversion module, the signal processing module, the tracking source signal generating module, the first change-over switch, the second change-over switch, the calibration module, the storage module, the signal input end and the signal output end;
the input end of the signal processing module is connected with the output end of the frequency conversion module and is used for acquiring the power of the output signal of the frequency conversion module;
the frequency conversion module comprises a first frequency conversion module, and the first frequency conversion module is used for converting the frequency of a signal input to the first frequency conversion module into a first intermediate frequency and outputting a first intermediate frequency signal;
the tracking source signal generating module is connected with the first frequency conversion module and used for generating a signal with a specific frequency, and the specific frequency is the same as the frequency selected and received by the first frequency conversion module;
the first end of the first selector switch is electrically connected with the frequency conversion module, and the second end of the first selector switch is switched between the signal input end and the output end of the calibration module and is used for connecting the signal input end to the input end of the frequency conversion module when calibration is not needed or connecting the output end of the calibration module to the input end of the frequency conversion module when calibration is needed;
the first end of the second selector switch is electrically connected with the tracking source signal generation module, and the second end of the second selector switch is switched between the signal output end and the input end of the calibration module and is used for connecting the output end of the tracking source signal generation module to the signal output end when calibration is not needed or connecting the output end of the tracking source signal generation module to the input end of the calibration module when calibration is needed;
the storage module is used for storing the standard power difference value △ PkWherein k =1,2 … …, n, n is a natural number equal to or greater than 1;
the signal processing module is also used for acquiring the power P of the signal of the equidistant frequency point detected by the calibration module when the calibration is neededT1kAnd the power P of the signal of the equal interval frequency point detected by the signal processing moduleT2kWherein k =1,2 … …, n, n is a natural number equal to or greater than 1; the signals of the equal interval frequency points are signals generated by the tracking source signal generating module under the preset output power; calculating the power P of each frequency point signalT1kAnd PT2kDifference value △ P ofTkDifference △ PTkStandard power difference △ P of frequency point signal corresponding to presetkComparing to obtain a power compensation value of each frequency point signal; and compensating the power of the input signal of the corresponding frequency point output by the spectrum analyzer according to the power compensation value of each frequency point signal.
Further, the power compensation value C of each frequency point signal is obtained according to the following formulak：
Ck=△Pk-△PTk
Wherein, △ PkAs a standard power difference, △ PTkIs a power PT1KAnd PT2kThe difference of (a).
The calibration module is used for calibrating the output end of the calibration module, and controlling the output end of the calibration module to be connected with the control end of the first switch and the control end of the second switch respectively.
Furthermore, the calibration module comprises a coupler and a power detection device, an input end of the coupler is connected with an output end of the tracking source signal generation module, a second output end of the coupler is connected with an input end of the first frequency conversion module, and an input end of the power detection device is connected with a first output end of the coupler and is used for detecting the power of the signal with the specific frequency generated by the tracking source signal generation module.
Further, the coupler is a coupling resistor.
Furthermore, the power detection device comprises a radio frequency detection module and an analog-to-digital conversion module, wherein the input end of the radio frequency detection module is connected with the first output end of the coupler and is used for converting the amplitude envelope curve of the signal output by the first output end of the coupler into direct-current voltage; the analog-to-digital conversion module is connected with the output end of the radio frequency detection module and is used for detecting the direct current voltage output by the radio frequency detection module.
Further, the first frequency conversion module comprises a first frequency mixer, a first local oscillator, a first coupler and a first intermediate frequency filter;
the first local oscillator is used for generating a local oscillator frequency sweeping signal;
the first coupler is used for extracting local oscillation frequency sweeping signals generated by a first local oscillation, dividing the local oscillation frequency sweeping signals into two paths, outputting one path of the local oscillation frequency sweeping signals to the tracking source signal generation module through a first output end of the first coupler, and outputting the other path of the local oscillation frequency sweeping signals to the first frequency mixer through a second output end of the first coupler;
the first mixer is used for mixing a signal input to the first mixer with a local oscillator signal output by the first coupler to obtain a first intermediate frequency signal;
the first intermediate frequency filter is used for filtering signals except for signals of a first intermediate frequency.
Furthermore, the frequency conversion module also comprises a second frequency conversion module and a third frequency conversion module;
the input end of the second frequency conversion module is connected with the output end of the first frequency conversion module and is used for carrying out frequency conversion on the first intermediate-frequency signal output by the first frequency conversion module to obtain a second intermediate-frequency signal;
the input end of the third frequency conversion module is connected with the output end of the second frequency conversion module and is used for carrying out frequency conversion on the second intermediate-frequency signal output by the second frequency conversion module to obtain a third intermediate-frequency signal; and the output end of the third frequency conversion module is connected with the signal processing module and is used for detecting the power of the third intermediate frequency signal.
Further, the tracking source signal generating module comprises a tracking source mixer and a tracking source local oscillator;
the tracking source local oscillator is used for generating a sinusoidal signal with the same frequency as the first intermediate frequency signal;
the tracking source frequency mixer comprises a first input end, a second input end and an output end, wherein the first input end is connected with the first output end of the first coupler, the second input end is connected with the output end of the tracking source local oscillator, and the tracking source frequency mixer is used for mixing the local oscillator frequency sweeping signal input to the tracking source frequency mixer with the sinusoidal signal output by the tracking source local oscillator.
Furthermore, the spectrum analyzer also comprises a display module and a control panel, wherein the display module is used for displaying the frequency and the amplitude of the signal measured by the spectrum analyzer; and the control panel is provided with a button for controlling the first change-over switch and the second change-over switch to be switched.
According to the spectrum analyzer with temperature compensation function of the above embodiment, when calibration is needed, the input end of the calibration module is connected with the output end of the tracking source signal generation module through the first switch, to measure the power of the output signal of the tracking source signal generation module, and connect the calibration module with the frequency conversion module through the second switch, the power of the signal in the receiving channel of the spectrum analyzer is measured by a signal processing module connected with a frequency conversion module, the output display power of the spectrum analyzer is compensated by comparing the power difference value in the signal processing module and the calibration module with the preset standard power difference value, and because the tracking source signal generation module can output the signal of any frequency point in the maximum measurement frequency range of the spectrum analyzer, the temperature compensation can be carried out on the signal power of any frequency point in the full frequency band.
Drawings
FIG. 1 is a schematic diagram of a prior art spectrum analyzer with integrated tracking source;
FIG. 2 is a schematic structural diagram of a spectrum analyzer with temperature compensation according to an embodiment;
FIG. 3 is a schematic structural diagram of a specific spectrum analyzer with temperature compensation function according to an embodiment;
fig. 4 is a flowchart illustrating temperature compensation of a spectrum analyzer with temperature compensation according to an embodiment.
Detailed Description
The present invention will be described in further detail with reference to the following detailed description and accompanying drawings. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.
Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.
The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).
The structure of the existing spectrum analyzer with an integrated tracking source is shown in fig. 1, a signal input by an input end of the spectrum analyzer is subjected to frequency mixing processing of a first frequency mixer, a second frequency mixer and a third frequency mixer in sequence to obtain a required third intermediate frequency signal, the third intermediate frequency signal is input into an analog-to-digital conversion module and then power of the intermediate frequency signal can be output, and the power of the third intermediate frequency signal minus the gain of a receiving channel is equal to the power of the input signal at the input end; then, configuring the frequency of the local oscillation frequency sweeping signal output by the first local oscillator to enable the frequency of a first intermediate frequency signal obtained after the local oscillation frequency sweeping signal and the input signal of the input end are mixed in the first mixer to be a preset value, adding or subtracting the frequency of the first intermediate frequency signal to or from the frequency of the local oscillation frequency sweeping signal to obtain the frequency of the input signal of the input end, and completing the basic work of the spectrum analyzer to enable the spectrum analyzer to output the frequency and power information of the input signal of the input end; if a tracking source is added on the basis of the spectrum analyzer, the output frequency of a local oscillator of the tracking source is set to be a first intermediate frequency, and the local oscillator frequency sweeping signal and a signal output by the local oscillator of the tracking source are mixed by a frequency mixer of the tracking source, so that the output frequency of the frequency mixer of the tracking source is the same as the frequency selected and received by a first frequency conversion module, as shown in fig. 1, the frequency of the signal is selected and received by the input end of the frequency tracking spectrum analyzer of the output signal of the tracking source, and the tracking function of the tracking source is realized.
Because the frequency of the received signal is selected by the frequency tracking spectrum analyzer input end of the tracking source output signal, and the tracking source can realize the tracking of the full frequency band, a calibration module can be added on the spectrum analyzer integrated with the tracking source, and the temperature compensation of the full frequency band signal of the spectrum analyzer can be realized.
In the embodiment of the invention, when calibration is not needed, the second end of the first change-over switch is controlled to be switched to the signal input end, so that the signal input end is electrically connected with the first frequency conversion module, and then the second end of the second change-over switch is controlled to be switched to the signal output end, so that the tracking source signal generation module is electrically connected with the signal output end, so that the basic function of the integrated tracking source spectrum analyzer is realized, the tracking source tracking spectrum analyzer selects the received frequency, and the signal with the specific frequency is output through the signal output end.
When the calibration is needed, the second end of the first switch is controlled to be switched to the output end of the calibration module, so that the first frequency conversion module is electrically connected with the calibration module, and then the second end of the second change-over switch is controlled to be switched to the input end of the calibration module, the signals of the equal interval frequency points output by the tracking source signal generating module under the preset power are respectively input into the calibration module and the frequency conversion module, the output end of the frequency conversion module is connected with the input end of the signal processing module, the power of each frequency point signal detected in the calibration module and the signal processing module is respectively obtained through the signal processing module, the power difference between the frequency point signals is calculated, the power difference of each frequency point signal is compared with the standard power difference of a preset corresponding frequency point signal, a compensation value corresponding to each frequency point signal is obtained, and the temperature compensation is carried out on the spectrum analyzer through the compensation value.
Example (b):
referring to fig. 2, fig. 2 is a schematic structural diagram of a spectrum analyzer with temperature compensation function according to this embodiment, where the spectrum analyzer includes a frequency conversion module 2, a signal processing module 3, a tracking source signal generation module 4, a first switch S1, a second switch S2, a calibration module 5, a control module 7, a storage module, a signal input end 1, and a signal output end 6;
the input end of the signal processing module 3 is connected with the output end of the frequency conversion module 2 and is used for acquiring the power of the output signal of the frequency conversion module 2; the signal processing module 3 includes an analog-to-digital conversion module 301, which performs AD sampling on the signal input to the signal processing module 3 and outputs a sampling value, where the output sampling value is an amplitude of the signal input to the signal processing module.
As shown in fig. 3, the frequency conversion module 2 includes a first frequency conversion module 10, the first frequency conversion module 10 is configured to convert a frequency of a signal input to the first frequency conversion module 10 into a first intermediate frequency, and output a first intermediate frequency signal, the first frequency conversion module 10 has a selection function at the same time, only a signal with a frequency = first local oscillator frequency — first intermediate frequency is converted into the first intermediate frequency for subsequent frequency conversion and signal processing, signals with other frequencies are filtered out, the first intermediate frequency is fixed, and selection of different frequency signals at an input end can be achieved by changing the first local oscillator frequency.
The first frequency conversion module 10 includes a first mixer, a first local oscillator, a first coupler, and a first intermediate frequency filter;
the first local oscillator is used for generating a local oscillator frequency sweeping signal under the control of the control module; the first coupler is used for extracting local oscillation frequency sweeping signals generated by a first local oscillation, dividing the local oscillation frequency sweeping signals into two paths, outputting one path of the local oscillation frequency sweeping signals to the tracking source signal generation module through a first output end of the first coupler, and outputting the other path of the local oscillation frequency sweeping signals to the first frequency mixer through a second output end of the first coupler; the first mixer is used for mixing the signal input into the first mixer with the local oscillator signal output by the first coupler to obtain a first intermediate frequency signal; the first intermediate frequency filter is used for filtering signals except for signals of the first intermediate frequency.
Specifically, the frequency of the local oscillator frequency sweep signal is variable, and the signal with any frequency input to the first frequency conversion module 10 may be converted to the first intermediate frequency by configuring the frequency of the local oscillator frequency sweep signal, and if the frequency fin of the input signal satisfies: fLO1 (first local oscillator swept frequency) -fin = fIF1 (first intermediate frequency), and the frequency-converted signal may pass through the first intermediate frequency filter, otherwise, the frequency-converted signal may be filtered by the first intermediate frequency filter, so that the first frequency conversion module may implement a function of selecting a receiving frequency, and meanwhile, the frequency of the local oscillator swept frequency signal and the frequency of the first intermediate frequency are known, so that the frequency of the received signal may be derived.
The tracking source signal generating module 4 is connected to the first frequency conversion module 10, and is configured to generate a signal with a specific frequency, where the specific frequency is the same as a frequency selected by the first frequency conversion module 10 for reception, and the frequency selected by the first frequency conversion module 10 is a frequency selected by changing the first local oscillation frequency to input the signal into the first frequency conversion module 10.
As shown in fig. 3, the trace source signal generation module 4 includes a trace source mixer and a trace source local oscillator; the tracking source local oscillator is used for generating a sine wave signal with the same frequency as the first intermediate frequency signal under the control of the control module; the tracking source frequency mixer comprises a first input end, a second input end and an output end, wherein the first input end is connected with the first output end of the first coupler, the second input end is connected with the output end of the tracking source local oscillator and is used for mixing the local oscillator frequency sweeping signal input to the tracking source frequency mixer with the signal output by the tracking source local oscillator, and the frequency of the signal output by the frequency mixer is equal to the frequency selected and received by the first frequency conversion module 10.
A first end of the first switch S1 is electrically connected to the frequency conversion module 2, and a second end of the first switch is switched between the signal input end 1 and the output end of the calibration module 5, so as to connect the signal input end 1 to the input end of the frequency conversion module 2 when calibration is not required, or connect the output end of the calibration module 5 to the input end of the frequency conversion module 2 when calibration is required;
as shown in fig. 3, the frequency conversion module 2 in this embodiment further includes a second frequency conversion module 8 and a third frequency conversion module 9; the input end of the second frequency conversion module 8 is connected with the output end of the first frequency conversion module 10, and is used for performing frequency conversion on the first intermediate-frequency signal output by the first frequency conversion module 10 to obtain a second intermediate-frequency signal; the input end of the third frequency conversion module 9 is connected to the output end of the second frequency conversion module 8, and is configured to convert the second intermediate frequency signal output by the second frequency conversion module 8 to obtain a third intermediate frequency signal; the output end of the third intermediate frequency is connected to the signal processing module 3, and the signal processing module 3 includes an ADC analog-to-digital conversion module 301, which can extract the power of the third intermediate frequency signal.
The second switch S2 has a first terminal electrically connected to the tracking source signal generating module 4 and a second terminal switched between the signal output terminal 6 and the input terminal of the calibration module 5 for connecting the tracking source signal generating module 4 to the signal output terminal 6 when calibration is not required or connecting the tracking source signal generating module 4 to the input terminal of the calibration module 5 when calibration is required.
In this embodiment, the switching between the first switch S1 and the second switch S2 may be controlled manually or automatically by a control module, as shown in fig. 2 and 3, the control module 7 is respectively connected to the control terminal of the first switch S1 and the control terminal of the second switch S2, and is configured to control the second terminal of the first switch S1 to switch between the signal input terminal and the output terminal of the calibration module 5, and control the second terminal of the second switch S2 to switch between the signal output terminal 6 and the input terminal of the calibration module 5. When the first switch S1 and the second switch S2 are automatically controlled to switch, a temperature detection module, which may be a temperature sensor or other device with a temperature detection function, needs to be installed on the spectrum analyzer, and when the temperature detection module detects that the current temperature exceeds a threshold, the control module 7 sends a command to the first switch S1 and the second switch S2 to enable the calibration module 5 to be connected to the spectrum analyzer circuit, and when the calibration is completed, the control module 7 sends a command to the first switch S1 and the second switch S2 again to enable the spectrum analyzer to recover its normal operation circuit. The first switch S1 and the second switch S2 in this embodiment can be single-pole double-throw switches.
The embodiment can also adopt manual operation to control the switching of the first switch S1 and the second switch S2, and the manual operation comprises a control panel, wherein a button for controlling the switching of the first switch and the second switch is arranged on the control panel, and a user can directly switch the working state of the spectrum analyzer by selecting the button.
When calibration is not needed, the calibration module is not connected to the spectrum analyzer circuit, and the signal input terminal 1 is connected to the first frequency conversion module 10 through the first switch S1, and the trace source signal generation module 4 is connected to the signal output terminal 6 through the second switch S2, where the circuit connection in the spectrum analyzer is that of a spectrum analyzer with a conventional integrated trace source.
The control module 7 in this embodiment is used for controlling the spectrum analyzer to perform calibration when the spectrum analyzer finds that the temperature T exceeds the factory calibration temperature by a certain threshold value in the using processPreparing; during calibration, the second terminal of the first switch S1 is switched to the output terminal of the calibration module 5, and the second terminal of the second switch S2 is switched to the input terminal of the calibration module 5. Acquiring the power P of the signal of the equispaced frequency points detected by the calibration module 5T1kAnd the power P of the signal of the equal interval frequency point detected by the signal processing module 3T2kWherein k =1,2 … …, n, n is a natural number equal to or greater than 1; and the signals of the equal interval frequency points are generated by the tracking source signal generating module under the preset output power.
Calculating the power P of each frequency point signal through a signal processing moduleT1kAnd PT2kDifference △ PTkDifference △ PTkStandard deviation value △ P of frequency point signal corresponding to presetkComparing to obtain power compensation value of each frequency point signal, wherein the storage module is used for storing standard deviation value △ PkWherein k =1,2 … …, n, n is a natural number of 1 or more.
And the signal processing module compensates the power of the corresponding frequency point output by the spectrum analyzer according to the power compensation value of each frequency point signal.
Obtaining the power compensation value C of each frequency point signal according to the formula Ik：
Ck=△Pk-△PTkFormula one
Wherein, △ PkIs the difference between the standard powers, △ PTkIs a power PT1KAnd PT2kThe difference of (a).
Standard Power Difference △ P in this examplekThe calibration method can be used for calibrating the spectrum analyzer once before the factory shipment.
The calibration module 5 comprises a coupler and a power detection device, the coupler comprises an input end, a first output end and a second output end, the input end of the coupler is connected with the output end of the tracking source signal generation module 4 and is used for dividing a signal of a specific frequency generated by the tracking source signal generation module under preset output power into two paths of signals, the specific frequency is any one of frequency points with equal intervals, the two paths of signals are respectively output through the first output end and the second output end of the coupler, the input end of the power detection device is connected with the first output end of the coupler and is used for detecting the power of the signal of the specific frequency generated by the tracking source signal generation module under the preset output power, and the second output end of the coupler is connected with the input end of the first frequency conversion module.
In the embodiment, a signal output by a tracking source signal generation module is used as a calibration signal, the calibration signal is divided into two paths through a coupler of a calibration module, one path is input into a power detection device, and the power of the calibration signal is detected through the power detection device; the other path is input to the first frequency conversion module 10, and the signal passes through a receiving channel formed by the first frequency conversion module 10, the second frequency conversion module 8 and the third frequency conversion module 9, and then the power of the signal is detected through the ADC analog-to-digital conversion module 301.
The coupler and the first coupler in this embodiment may be any devices capable of dividing one input signal into multiple signals with the same frequency, such as a directional coupler, a power divider, and the like.
The power detection device in the embodiment comprises a radio frequency detection module and an analog-to-digital conversion module, wherein the input end of the radio frequency detection module is connected with the first output end of the coupler and is used for converting the amplitude envelope curve of a signal output by the first output end of the coupler into direct-current voltage; the output end of the radio frequency detection module is connected with the analog-to-digital conversion module and used for detecting the direct current voltage output by the radio frequency detection module. The radio frequency detection module is used for obtaining the power of signals, and can be realized by adopting a radio frequency detector integrated chip or a built circuit.
Based on the spectrum analyzer with temperature compensation function, fig. 4 shows a working flow chart of the spectrum analyzer for temperature compensation under a specific embodiment, which includes the following working steps:
101, performing factory calibration of temperature compensation, switching a second end of the first switch S1 to an output end of a calibration module, and switching a second end of the second switch S2 to an input end of the calibration module;
step 102, recording the temperature of the time-frequency spectrum analyzer, and taking the temperature as a calibration temperature;
103, selecting different frequency intervals according to the required compensation precision;
step 104, setting the output power of the tracking source signal generation module to be PTGConfiguring a first local oscillator according to the set frequency interval to make the output frequency of the tracking source signal generation module be FC1、FC2…FCnOf a signal of (D) at a frequency of FC1、FC2…FCnThen, the difference Δ P between the power of the received channel signal and the power of the calibration signalC1、ΔPC2…ΔPCn；
The above process is calibration of the spectrum analyzer at the time of factory shipment.
Step 105, entering a normal working mode after the calibration is finished, namely connecting the second end of the first switch S1 with a signal input end and connecting the second end of the second switch S2 with a signal output end;
step 106, reading the working temperature of the spectrum analyzer at intervals, and executing step 107 if the difference value between the current working temperature and the calibration temperature exceeds a preset threshold value; otherwise, continuing to execute the operation of reading the temperature;
step 107, the spectrum analyzer enters a temperature calibration mode, that is, the second terminal of the first switch S1 is switched to the output terminal of the calibration module, and the second terminal of the second switch S2 is switched to the input terminal of the calibration module;
step 108, setting the output power of the tracking source signal generation module to be PTGConfiguring the frequency of the first local oscillator according to the set frequency interval so that the output frequency of the tracking source signal generation module is FC1、FC2…FCnOf a signal of (D) at a frequency of FC1、FC2…FCnThen, the difference Δ P between the power of the received channel signal and the power of the calibration signal1、ΔP2…ΔPT；
Step 109, calculating the frequency at FC1、FC2…FCnLower compensation value CP1、CP2…CPn(ii) a To pairIn the position different from FC1、FC2…FCnFrequency point signals on the frequency are obtained by adopting the relation between the compensation value and the frequency through a curve fitting mode;
step 110, compensating the power of the displayed signal according to the compensation value at the signal processing module, specifically: spectrum analyzer display power = power value measured in uncompensated state + compensation value.
The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. For a person skilled in the art to which the invention pertains, several simple deductions, modifications or substitutions may be made according to the idea of the invention.
Claims (10)
1. A spectrum analyzer with temperature compensation, comprising: the tracking source signal generating module is connected with the frequency conversion module, the signal processing module, the tracking source signal generating module, the first change-over switch, the second change-over switch, the calibration module, the storage module, the signal input end and the signal output end;
the input end of the signal processing module is connected with the output end of the frequency conversion module and is used for acquiring the power of the output signal of the frequency conversion module;
the frequency conversion module comprises a first frequency conversion module, and the first frequency conversion module is used for converting the frequency of a signal input to the first frequency conversion module into a first intermediate frequency and outputting a first intermediate frequency signal;
the tracking source signal generating module is connected with the first frequency conversion module and used for generating a signal with a specific frequency, and the specific frequency is the same as the frequency selected and received by the first frequency conversion module;
the first end of the first selector switch is electrically connected with the frequency conversion module, and the second end of the first selector switch is switched between the signal input end and the output end of the calibration module and is used for connecting the signal input end to the input end of the frequency conversion module when calibration is not needed or connecting the output end of the calibration module to the input end of the frequency conversion module when calibration is needed;
the first end of the second selector switch is electrically connected with the tracking source signal generation module, and the second end of the second selector switch is switched between the signal output end and the input end of the calibration module and is used for connecting the output end of the tracking source signal generation module to the signal output end when calibration is not needed or connecting the output end of the tracking source signal generation module to the input end of the calibration module when calibration is needed;
the storage module is used for storing the standard power difference value △ PkWherein k =1,2 … …, n, n is a natural number equal to or greater than 1;
the signal processing module is also used for acquiring the power P of the signal of the equidistant frequency point detected by the calibration module when the calibration is neededT1kAnd the power P of the signal of the equal interval frequency point detected by the signal processing moduleT2kWherein k =1,2 … …, n, n is a natural number equal to or greater than 1; the signals of the equal interval frequency points are signals generated by the tracking source signal generating module under the preset output power; calculating the power P of each frequency point signalT1kAnd PT2kDifference value △ P ofTkDifference △ PTkStandard power difference △ P of frequency point signal corresponding to presetkComparing to obtain a power compensation value of each frequency point signal; and compensating the signal power of the corresponding frequency point output by the spectrum analyzer according to the power compensation value of each frequency point signal.
2. The spectrum analyzer as claimed in claim 1, wherein the power compensation value C of each frequency point signal is obtained according to the following formulak：
Ck=△Pk-△PTk
Wherein, △ PkAs a standard power difference, △ PTkIs a power PT1KAnd PT2kThe difference of (a).
3. The spectrum analyzer of claim 1, further comprising a control module coupled to the control terminal of the first switch and the control terminal of the second switch, respectively, for controlling the second terminal of the first switch to switch between the signal input terminal and the output terminal of the calibration module, and for controlling the second terminal of the second switch to switch between the signal output terminal and the input terminal of the calibration module.
4. The spectrum analyzer as claimed in claim 1, wherein the calibration module comprises a coupler and a power detection means, the input of the coupler is connected to the output of the tracking source signal generation module, the second output is connected to the input of the first frequency conversion module, and the input of the power detection means is connected to the first output of the coupler for detecting the power of the signal of the specific frequency generated by the tracking source signal generation module.
5. The spectrum analyzer of claim 4, wherein the coupler is a coupling resistor.
6. The spectrum analyzer as claimed in claim 4 or 5, wherein the power detection means comprises a radio frequency detection module and an analog-to-digital conversion module, wherein an input terminal of the radio frequency detection module is connected to the first output terminal of the coupler for converting the amplitude envelope of the signal output from the first output terminal of the coupler into a DC voltage; the analog-to-digital conversion module is connected with the output end of the radio frequency detection module and is used for detecting the direct current voltage output by the radio frequency detection module.
7. The spectrum analyzer of claim 1, wherein the first frequency conversion module comprises a first mixer, a first local oscillator, a first coupler, and a first intermediate frequency filter;
the first local oscillator is used for generating a local oscillator frequency sweeping signal;
the first coupler is used for extracting local oscillation frequency sweeping signals generated by a first local oscillation, dividing the local oscillation frequency sweeping signals into two paths, outputting one path of the local oscillation frequency sweeping signals to the tracking source signal generation module through a first output end of the first coupler, and outputting the other path of the local oscillation frequency sweeping signals to the first frequency mixer through a second output end of the first coupler;
the first mixer is used for mixing a signal input to the first mixer with a local oscillator signal output by the first coupler to obtain a first intermediate frequency signal;
the first intermediate frequency filter is used for filtering signals except for signals of a first intermediate frequency.
8. The spectrum analyzer of claim 7, wherein the frequency conversion module further comprises a second frequency conversion module and a third frequency conversion module;
the input end of the second frequency conversion module is connected with the output end of the first frequency conversion module and is used for carrying out frequency conversion on the first intermediate-frequency signal output by the first frequency conversion module to obtain a second intermediate-frequency signal;
the input end of the third frequency conversion module is connected with the output end of the second frequency conversion module and is used for carrying out frequency conversion on the second intermediate-frequency signal output by the second frequency conversion module to obtain a third intermediate-frequency signal; and the output end of the third frequency conversion module is connected with the signal processing module and is used for detecting the power of the third intermediate frequency signal.
9. The spectrum analyzer of claim 7, wherein the trace-source signal generation module comprises a trace-source mixer and a trace-source local oscillator;
the tracking source local oscillator is used for generating a sinusoidal signal with the same frequency as the first intermediate frequency signal;
the tracking source frequency mixer comprises a first input end, a second input end and an output end, wherein the first input end is connected with the first output end of the first coupler, the second input end is connected with the output end of the tracking source local oscillator, and the tracking source frequency mixer is used for mixing the local oscillator frequency sweeping signal input to the tracking source frequency mixer with the signal output by the tracking source local oscillator.
10. The spectrum analyzer of claim 1, wherein the spectrum analyzer further comprises a display module and a control panel, the display module for displaying the frequency and amplitude of the signal measured by the spectrum analyzer; and the control panel is provided with a button for controlling the first change-over switch and the second change-over switch to be switched.
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