CN104811139B - Vector network analysis method based on the application of DDS spurious frequencies - Google Patents
Vector network analysis method based on the application of DDS spurious frequencies Download PDFInfo
- Publication number
- CN104811139B CN104811139B CN201510187868.1A CN201510187868A CN104811139B CN 104811139 B CN104811139 B CN 104811139B CN 201510187868 A CN201510187868 A CN 201510187868A CN 104811139 B CN104811139 B CN 104811139B
- Authority
- CN
- China
- Prior art keywords
- frequency
- voltage
- signal
- dds
- port
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000003012 network analysis Methods 0.000 title claims abstract description 7
- 238000000034 method Methods 0.000 title claims abstract description 6
- 238000001228 spectrum Methods 0.000 claims abstract description 13
- 238000001914 filtration Methods 0.000 claims abstract description 11
- 230000010355 oscillation Effects 0.000 claims abstract description 6
- 238000005070 sampling Methods 0.000 claims description 5
- 230000000694 effects Effects 0.000 claims description 3
- 238000010606 normalization Methods 0.000 abstract description 4
- 230000003595 spectral effect Effects 0.000 abstract 2
- 230000009286 beneficial effect Effects 0.000 abstract 1
- 230000011218 segmentation Effects 0.000 abstract 1
- 238000005516 engineering process Methods 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 238000012545 processing Methods 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
- Monitoring And Testing Of Transmission In General (AREA)
Abstract
The invention discloses the frequency spectrums of the vector network analysis method applied based on DDS spurious frequencies, first generation ideal DDS；To the spectral characteristic of preferable DDS, by changing clock frequency, different spectral characteristic can be obtained, local oscillator and the Sweep Source of RF are obtained by intercepting splicing to frequency segmentation；It inputs to device under test, the frequency of entire frequency band is generated in different frequency sections adjustment DDS FREQUENCY CONTROLs, the incident voltage and reflected voltage of input terminal and output terminal are obtained by device under test, it is mixed with local oscillation signal, the intermediate-freuqncy signal that filtered device low-pass filtering obtains, radiofrequency signal is added in port 1 by electric bridge, measures the normalization incident voltage and reflected voltage of its port 1 and port 2, obtains exit port 1 and 2 intermediate-freuqncy signal amplitude of port and phase；The beneficial effects of the invention are as follows at low cost, wide frequency range, economic value is good.
Description
Technical Field
The invention belongs to the technical field of communication measurement, and relates to a vector network analysis method based on DDS stray frequency application.
Background
The direct digital frequency synthesis (DDS) technology has been widely used in communication, radar, electronic countermeasure and other electronic systems, and has been gradually improved along with the development of digital integrated circuits and microelectronic technologies, thereby fully embodying its superior performances such as wide relative bandwidth, extremely short frequency conversion time, high frequency resolution, continuous output phase, output of wideband orthogonal signals, and convenient integration of programmable and fully digital structures. But due to the limitation of the current semiconductor technology, the applicable DDS frequency range is generally limited by the highest clock frequency, which restricts the application of the DDS frequency range in the high-bandwidth vector network analysis instrument.
The vector network analyzer is one of important measuring instruments in electronic measuring instruments, can measure the characteristics of a two-port network, and is widely applied to the fields of electronic information, communication, teaching research and the like.
Disclosure of Invention
The invention aims to use the current popular DDS technology, switch DDS clock frequency by control, obtain a higher-frequency sweep source by utilizing stray frequency of the DDS clock frequency, further develop an economical vector network analyzer with low cost and high cost performance, and solve the problem that the frequency range is generally limited by the clock frequency in the current direct digital frequency synthesis (DDS) technology.
The technical scheme adopted by the invention is as follows:
step 1: generating a spectrum of an ideal DDS;
step 2: for the spectrum characteristics of an ideal DDS, different spectrum characteristics can be obtained by modifying the clock frequency, and the local oscillator and the RF sweep frequency source are obtained by intercepting and splicing the frequency in sections;
and step 3: and (3) inputting the swept frequency source in the step (2) to a device to be tested through the standing-wave ratio bridge, adjusting the DDS frequency in different frequency bands to control and generate the frequency of the whole frequency band, obtaining the incident voltage and the reflected voltage of the input end and the output end through the standing-wave ratio bridge, respectively mixing the incident voltage and the reflected voltage with the local oscillator signal, performing low-pass filtering through a filter to obtain the intermediate frequency component, obtaining the amplitude and the phase of the intermediate frequency signal through measurement ADC sampling processing, and simultaneously obtaining the intermediate frequency signal by directly mixing and filtering the radio frequency source and the local oscillator, wherein the signal is used as a reference signal of other 4 paths of. The amplitude and the phase of the incident voltage and the reflected voltage of the port 1 and the port 2 can be obtained by carrying out normalization correction processing on the intermediate frequency signals of the port 1 and the port 2;
further, in step 3, the amplitudes and phases of the intermediate frequency signals at the output port 1 and the port 2 are:
LLolocal oscillation signal source, SRFThe radio frequency signal source is generated by a DDS (direct digital synthesizer) by utilizing a stray effect, and S is obtained by obtaining a device to be tested through an electric bridgea1Input terminal incident voltage, Sa2Incident voltage at the output terminal Sb1Reflected voltage at input, Sb2Reflected voltage at the output, these four parameters representing the normalized incident and reflected voltages at ports 1 and 2, respectively, by measurement Sa1，Sa2Sb1Sb2Amplitude and phase to obtain device characteristics;
wherein,
(1)LLolocal oscillator signal
(2)SRFRadio frequency signal source
LLoLocal oscillator signal source, SRFThe amplitude of the frequency switching point of the signal source of the radio frequency signal source continuously changes along with the frequency,
a (f) ═ sinc (pi f/f _ CLK), I is a reference value, and f _ CLK is a clock frequency;
the frequency mixing result of the local oscillator signal and the radio frequency signal:
high frequency after signal mixing
Low frequency part after signal mixing
Filtering low-pass filtering the medium frequency component:
this intermediate frequency signal serves as a reference signal. Can be used to measure the incident and reflected voltages, S, of ports 1 and 2a1，Sa2Sb1Sb2And (6) normalization processing. Defining the phases of an RF signal port 1 and a port 2 normalized incident voltage and reflected voltage, and acquiring the phases of intermediate-frequency signals incident and reflected by each port as follows through frequency mixing filtering;
is provided with(5) Relative phase of intermediate frequency signal of incident voltage at input end
(6) Relative phase of intermediate frequency signal of input end reflected voltage
(7) Relative phase of intermediate frequency signal of incident voltage at output end
(8) The relative phase of the intermediate frequency signal of the reflected voltage at the output end can directly represent the incident voltage and the reflected voltage of the port 1 and the port 2, Sa1，Sa2Sb1Sb2The phase relationship of (1).
The amplitude and the phase of the intermediate frequency signals of the port 1 and the port 2 can be measured through AD sampling calculation;
the input end is used for inputting intermediate frequency signals after voltage mixing;
reflecting the intermediate frequency signal after voltage mixing at the input end;
the output end is used for inputting intermediate-frequency signals after voltage mixing;
reflecting the intermediate frequency signal after voltage mixing at the output end;
the following can be obtained:
(9) the input end incident voltage normalizes the amplitude;
(10) the input end reflects the normalized amplitude of the voltage;
(11) the input end reflects the normalized amplitude of the voltage;
(12) and the input end reflects the voltage normalized amplitude.
The invention has the advantages of low cost, wide frequency range and good economic value.
Drawings
FIG. 1 is an ideal DDS spectrum diagram;
FIG. 2 is a basic functional block diagram of a DDS;
FIG. 3 is an ideal DDS spurious profile;
fig. 4 is a diagram of a maximum signal envelope.
Detailed Description
The present invention will be described in detail with reference to the following embodiments.
The vector network analysis method based on the DDS stray frequency application is carried out according to the following steps:
step 1: an ideal DDS spectrum is generated, and fig. 1 is an ideal DDS spectrum with a clock frequency of 200M. Wherein, FoutIs the DDS desired output signal.
Step 2: for the spectrum characteristics of an ideal DDS, different spectrum characteristics can be obtained by modifying the clock frequency, and a local oscillator and an RF (radio frequency) sweep source are obtained by intercepting and splicing the frequency in sections; the frequency switching is as shown in table 1, here, the clock crystal oscillator 12M obtains the corresponding frequency by setting the pre-dividing frequency and adjusting the frequency multiplication coefficient. The frequency switching point mainly considers the spectrum amplitude and the interference after the local oscillator and other harmonic waves of the RF are mixed. Setting frequency section, calling corresponding local oscillator, RF and DDS output to make stray frequency point of local oscillator and RFThere is a 1.2K frequency difference.
TABLE 1
And step 3: and (3) inputting the radio frequency signal source in the step (2) into the port 1 of the device to be tested through the bridge, and adjusting the DDS frequency in different frequency bands to control the frequency of the whole frequency band. Obtaining incident voltage and reflected voltage of the ports 1 and 2 through an electric bridge;
obtaining Sa1--Sb2Four parameters:
the whole system is shown in FIG. 2, LLoLocal oscillation signal source, SRFThe radio frequency signal source is generated by DDS by utilizing stray effect, and the device S to be tested is obtained through the bridgea1Input terminal incident voltage, Sa2Incident voltage at the output terminal Sb1Reflected voltage at input, Sb2Reflected voltage at the output, these four parameters representing the normalized incident and reflected voltages at ports 1 and 2, respectively, by measurement Sa1，Sa2Sb1Sb2Amplitude and phase to obtain device characteristics.
Wherein,
(1)LLoand (5) local oscillation signals.
(2)SRFRadio frequency signal source
LLoLocal oscillator signal source, SRFThe switching points of the rf signal source frequency are shown in table 1, and the amplitude of the rf signal source changes with the frequency, where a (f) is I × sinc (pi f/f _ CLK), I is a reference value, and f _ CLK is the clock frequency.
The frequency mixing result of the local oscillator signal and the radio frequency signal:
high frequency after signal mixing
Low frequency part after signal mixing
Filtering low-pass filtering the medium frequency component:
this intermediate frequency signal is used as a reference signal for the incident and reflected voltages, S, of ports 1 and 2a1，Sa2Sb1Sb2And (6) normalization processing. Defining signal ports 1 and 2 normalizes the incident and reflected voltage phases.
Is provided with(5) Relative phase of incident voltage at input end
(6) Relative phase of reflected voltage at input terminal
(7) Relative phase of incident voltage at output end
(8) Relative phase of reflected voltage at output end
It can be seen that the intermediate frequency phase represents the port 1 and port 2 normalized incident and reflected voltage phase relationship.
The amplitude and phase of the frequency signals in the port 1 and the port 2 can be measured through AD sampling calculation.
The input end is used for inputting intermediate frequency signals after voltage mixing;
reflecting the intermediate frequency signal after voltage mixing at the input end;
the output end is used for inputting intermediate-frequency signals after voltage mixing;
reflecting the intermediate frequency signal after voltage mixing at the output end;
the following can be obtained:
(9) the input end incident voltage normalizes the amplitude;
(10) the input end reflects the normalized amplitude of the voltage;
(11) the input end reflects the normalized amplitude of the voltage;
(12) the input end reflects the normalized amplitude of the voltage;
the amplitude and phase of the intermediate frequency signal may be obtained by performing a Fast Fourier Transform (FFT) on the ADC samples.
SIFFFT (x _ n) (13) intermediate frequency signal AD sampling result x _ n
The invention is illustrated below by way of specific examples:
example 1: by switching different clock frequencies, the maximum amplitude among the three is taken at each point, and the resultant signal envelope is as shown in fig. 4. For example, if 380M spurs are desired, a 260M clock and a 120M fundamental frequency (380M-260M +120M) are preferably used. To obtain the envelope map of fig. 4, the maximum signal envelope map may be obtained by using a clock frequency of 400M within the output frequencies of 0-350M, 260M for the output frequencies of 350M-400M, then switching the clock frequency to 320M at the output frequencies of 400M-500M, and so on. Thereby obtaining LLo,SRFWhere f islo,fRFThe frequency difference is 1.2K for the intermediate frequency measurement.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not intended to limit the present invention in any way, and all simple modifications, equivalent variations and modifications made to the above embodiments according to the technical spirit of the present invention are within the scope of the present invention.
Claims (1)
1. The vector network analysis method based on the DDS stray frequency application is characterized by comprising the following steps of:
step 1: generating a spectrum of an ideal DDS;
step 2: for the frequency spectrum characteristics of an ideal DDS, different frequency spectrum characteristics are obtained by modifying clock frequency, and a local oscillator and a RF (radio frequency) sweep source are obtained by intercepting and splicing frequency segments;
and step 3: inputting the sweep frequency source obtained in the step 2 into a device to be tested, adjusting the DDS frequency in different frequency bands to control the frequency of the whole frequency band to pass through the device to be testedThe measuring device obtains the incident voltage and the reflected voltage of the input end and the output end, mixes the local oscillation signal with the radio frequency signal and the incident reflected signal of each port, obtains an intermediate frequency signal through low-pass filtering, and thus obtains the normalized incident voltage and the normalized reflected voltage Sa1，Sa2，Sb1And Sb2Amplitude and phase of; .
Wherein L isLoLocal oscillation signal source, SRFThe radio frequency signal source is generated by a DDS (direct digital synthesizer) by utilizing a stray effect, and S is obtained through a device to be testeda1Input terminal incident voltage, Sa2Incident voltage at the output terminal Sb1Reflected voltage at input, Sb2Reflected voltage at the output terminal by measuring Sa1，Sa2，Sb1And Sb2To obtain device characteristics; wherein,
LLolocal oscillator signal
SRFRadio frequency signal source
LLoLocal oscillator signal source, SRFThe amplitude of a frequency switching point of the signal source is constantly changed along with the frequency, A (f) is I sinc (pi f/f _ CLK), I is a reference value, and f _ CLK is clock frequency;
the frequency mixing result of the local oscillator signal and the radio frequency signal:
high frequency after signal mixing
Low frequency part after signal mixing
Obtaining the intermediate frequency component through low-pass filtering:
the intermediate frequency signal is used as a reference signal, and the phases of the intermediate frequency signals incident and reflected by each port are obtained through frequency mixing filtering as follows;
is provided withRelative phase of incident voltage at input end
Relative phase of reflected voltage at input terminal
Relative phase of incident voltage at output end
Relative phase of reflected voltage at output end
Calculating and measuring the amplitude and the phase of the intermediate frequency signals of the port 1 and the port 2 through AD sampling;
the input end is used for inputting intermediate frequency signals after voltage mixing;
reflecting the intermediate frequency signal after voltage mixing at the input end;
the output end is used for inputting intermediate-frequency signals after voltage mixing;
reflecting the intermediate frequency signal after voltage mixing at the output end;
obtaining:
normalizing the amplitude of the incident voltage at the input end;
the input end reflects the normalized amplitude of the voltage;
the input end reflects the normalized amplitude of the voltage;
the input end reflects the normalized amplitude of the voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510187868.1A CN104811139B (en) | 2015-04-20 | 2015-04-20 | Vector network analysis method based on the application of DDS spurious frequencies |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510187868.1A CN104811139B (en) | 2015-04-20 | 2015-04-20 | Vector network analysis method based on the application of DDS spurious frequencies |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104811139A CN104811139A (en) | 2015-07-29 |
| CN104811139B true CN104811139B (en) | 2018-06-05 |
Family
ID=53695702
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510187868.1A Active CN104811139B (en) | 2015-04-20 | 2015-04-20 | Vector network analysis method based on the application of DDS spurious frequencies |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104811139B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110365350B (en) * | 2019-06-24 | 2021-11-16 | 成都振芯科技股份有限公司 | Method and device for enhancing adaptability of receiving channel orthogonal correction algorithm |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101149630A (en) * | 2007-09-28 | 2008-03-26 | 电子科技大学 | DDS signal source amplitude-frequency characteristic compensation method and related DDS signal source |
| CN102447470A (en) * | 2010-10-15 | 2012-05-09 | 卢珊 | Direct digital frequency synthesis (DDS)-based signal source |
| CN103346874A (en) * | 2013-06-20 | 2013-10-09 | 桂林电子科技大学 | Digital communication clock synchronization system based on DDS |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4520061B2 (en) * | 2001-03-08 | 2010-08-04 | 富士通オプティカルコンポーネンツ株式会社 | Rubidium atomic oscillator |
| US7336748B2 (en) * | 2003-12-23 | 2008-02-26 | Teradyne, Inc. | DDS circuit with arbitrary frequency control clock |
-
2015
- 2015-04-20 CN CN201510187868.1A patent/CN104811139B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101149630A (en) * | 2007-09-28 | 2008-03-26 | 电子科技大学 | DDS signal source amplitude-frequency characteristic compensation method and related DDS signal source |
| CN102447470A (en) * | 2010-10-15 | 2012-05-09 | 卢珊 | Direct digital frequency synthesis (DDS)-based signal source |
| CN103346874A (en) * | 2013-06-20 | 2013-10-09 | 桂林电子科技大学 | Digital communication clock synchronization system based on DDS |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104811139A (en) | 2015-07-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10564198B2 (en) | Spectrum analyzer using multiple intermediate frequencies and multiple clock configurations for residual, spurious and image signal reduction | |
| CN103067104B (en) | System and method for measuring radio-frequency signal high-speed sweeping frequency spectrum based on digital local oscillator | |
| US8378693B2 (en) | Vector network analyzer (VNA) on a chip | |
| US7801505B2 (en) | Multipulse/multitone mixing receiver | |
| US10684317B2 (en) | Vector network analyzer and measuring method for frequency-converting measurements | |
| CN110837002B (en) | Spectrum scanning measuring device and time domain waveform obtaining method | |
| CN103795475B (en) | Amplitude and the phase response calibration of receiver | |
| JP4711935B2 (en) | Equalization filter setting method | |
| US8744370B2 (en) | System for characterizing mixer or converter response | |
| CN104410469B (en) | Calibration method for tracking preselector based on built-in noise source | |
| US20190072594A1 (en) | Vector network analyzer and measuring method for frequency converting measurements | |
| US7629795B2 (en) | Vector impedance measurement system and method of using same | |
| US7030627B1 (en) | Wideband complex radio frequency impedance measurement | |
| JP5347507B2 (en) | Signal quality measurement device, spectrum measurement circuit, program | |
| CN104811139B (en) | Vector network analysis method based on the application of DDS spurious frequencies | |
| Mirra et al. | A multi-step phase calibration procedure for closely spaced multi-tone signals | |
| CN106199184A (en) | A kind of spectrum analyzer with quick phase-locked function | |
| EP2122372A1 (en) | Rf circuit analysis | |
| US9188617B2 (en) | Using a shared local oscillator to make low-noise vector measurements | |
| KR101325658B1 (en) | Characterization of a frequency response for a frequency translation device | |
| CN105306091B (en) | Crystal oscillation fractional frequency circuit for radio general measuring instrument RF local oscillator circuit | |
| Zeng et al. | Wideband signal transceiver module with a Doppler shift function | |
| Sharma et al. | Design and implementation of a reconfigurable wideband radio frequency spectrum analyzer with image rejection in the digital domain | |
| Will et al. | Phase measurement of RF devices using phase-shifting interferometry | |
| Yeom et al. | An Efficient Cross-Correlation Method for a Digital Phase Noise Measurement System. |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| EXSB | Decision made by sipo to initiate substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |