CN202870167U - System for realizing spectrum analyzer whole-band scanning by using point-by-point phase locking - Google Patents
System for realizing spectrum analyzer whole-band scanning by using point-by-point phase locking Download PDFInfo
- Publication number
- CN202870167U CN202870167U CN 201220568776 CN201220568776U CN202870167U CN 202870167 U CN202870167 U CN 202870167U CN 201220568776 CN201220568776 CN 201220568776 CN 201220568776 U CN201220568776 U CN 201220568776U CN 202870167 U CN202870167 U CN 202870167U
- Authority
- CN
- China
- Prior art keywords
- frequency
- local oscillator
- scanning
- mixer
- amplifier
- 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.)
- Expired - Lifetime
Links
Images
Landscapes
- Superheterodyne Receivers (AREA)
Abstract
A system for realizing spectrum analyzer whole-band scanning by using point-by-point scanning comprises a first local oscillator, a first frequency mixer, a second local oscillator, a second frequency mixer, a third local oscillator, a third frequency mixer, a digital intermediate frequency processing module, a first amplifier, a first filter, a second amplifier and a second filter. A radio frequency signal, after entering a radio frequency channel, is sent to the first frequency mixer, is mixed with the first local oscillator and generates a first intermediate frequency; the first intermediate frequency is amplified by the first amplifier and filtered by the first filter, is mixed with the second local oscillator by the second frequency mixer and generates a second intermediate frequency; the second intermediate frequency is amplified by the second amplifier and filtered by the second filter, and then is mixed with the third local oscillator by the third frequency mixer and generates a third intermediate frequency. As such, the radio frequency signal completes radio frequency down-conversion through three levels of frequency conversion. The digital intermediate frequency processing module is used for digital processing. The first local oscillator complete scanning by point-by-point phase locking during the whole scanning process, and thus when a scanning span is increased, the system improves frequency accuracy of the spectrum analyzer.
Description
Technical field
The utility model relates to the spectrum analyzer field, and especially the system of Spectrum Analyzer full frequency band scanning is specially the system that utilizes the scanning of the phase-locked realization frequency spectrograph of pointwise full frequency band.
Background technology
Along with the different occasions of every field to utilizing improving constantly of spectrum analyzer test request, the local oscillator technology of spectrum analyzer has progressively become one of gordian technique of weighing frequency spectrograph overall performance height, past spectrum analyzer till now generally all adopts superhet technology, all take to scan the first local oscillator, fix the mode of all the other local oscillators, the scanning of frequency spectrograph complete machine realizes by the scanning of the first local oscillator.Therefore the performance of the first local oscillator becomes the key of complete machine.The first local oscillator of early stage spectrum analyzer is used open YIG oscillator, frequency stability is relatively poor, residual FM is also larger, the frequency locking formula local oscillator that develops afterwards, frequency stability and residual FM increase, local oscillator in the present high-performance spectrum analyzer all is to have used phase-locking type to synthesize local oscillator, output signal is locked on the very high reference frequency of degree of stability, reference frequency is generally by the TCXO(temperature compensating crystal oscillator) or the OCXO(constant-temperature crystal oscillator) provide, synthetic local oscillator can reach very little residual FM.Frequency spectrograph is swept wide degree setting SPAN() and the RBW(resolution bandwidth) after, also determined the number of scan points in the single pass process, number of scan points has determined that the first local oscillator is by great step-scan, when number of scan points is fewer, local oscillator adopts every all phase-locked mode in scanning process, but when number of scan points increases, particularly in full frequency band scanning, consider the factor of sweep time, the first local oscillator of frequency spectrograph is taked is as shown in Figure 1 locking initial frequency point, perhaps lock starting point and ending point 2 points, the mode of all the other frequency point opened loop scannings is finished scanning, local oscillator in the scanning process has certain uncertainty, and this mode has affected the frequency accuracy of frequency spectrograph overall measurement.
The utility model content
Technical matters to be solved: provide a kind of system that utilizes the scanning of the phase-locked realization frequency spectrograph of pointwise full frequency band for above problem the utility model, be under the condition of any setting in sweep length and resolution bandwidth, local oscillator to the phase-locked scanning of each Frequency point pointwise, has improved frequency spectrograph and has swept frequency accuracy under wide in difference in scanning process.
Technical scheme: the system for above not enough the utility model provides the phase-locked realization frequency spectrograph of a kind of pointwise full frequency band to scan comprises the first local oscillator, the first frequency mixer, the second local oscillator, the second frequency mixer, the 3rd local oscillator, three-mixer, Digital IF Processing module; It is characterized in that: also comprise the first amplifier, the first wave filter, the second amplifier, the second wave filter; Radiofrequency signal is delivered to the first frequency mixer and is produced the first intermediate frequency with the first local oscillator mixing after entering the radio-frequency channel, the first intermediate frequency amplify through the first amplifier and the first filter filtering after by the second frequency mixer with generation the second intermediate frequency after itself and the second local oscillator mixing, the second intermediate frequency amplify through the second amplifier and the second filter filtering after by three-mixer with generation the 3rd intermediate frequency after itself and the 3rd local oscillator mixing, radiofrequency signal is finished radio frequency down-conversion through three grades of frequency conversions, and the Digital IF Processing module is used for carrying out digital processing.
Described the first local oscillator is taked the phase-locked scan mode of pointwise, and it is phase-locked namely to scan omnidistance pointwise, and the digital signal of Digital IF Processing module after to Digital Down Convert is divided into two kinds of processing modes: a kind of is the digital detection mode; Another kind is FFT " Fast Fourier Transform (FFT) " mode; The selection of dual mode is that the setting according to RBW " resolution bandwidth " decides; The intermediate value that resolution bandwidth is set is 1kHz, and the resolution bandwidth that frequency spectrograph is set and 1KHz determine the stepping set-up mode that the first local oscillator pointwise is phase-locked more afterwards:
1. when the set resolution belt of frequency spectrograph was wider than 1KHz, the Digital IF Processing module selected to adopt the mode of digital detection, and under the analytical model of digital detection, the setting of sweep length is until full frequency band scanning; The number of scan points of the first local oscillator output is to draw according to frequency spectrograph set sweep length and resolution bandwidth, number of scan points in the sweep length scope has determined that the first local oscillator is according to great step value pointwise output frequency, " number of scan points＞sweep length ÷ resolution bandwidth; for the ease of showing; usually being fixedly installed is 501,1001,2001 points; step value=sweep length ÷ number of scan points, and＜resolution bandwidth ";
2. when the set resolution bandwidth of frequency spectrograph was less than or equal to 1KHz, the Digital IF Processing module selected to adopt the mode of FFT, and under the analytical model of FFT, the setting of sweep length is until the minimum sweep length 100Hz of frequency spectrograph; The number of scan points of the first local oscillator output is to determine according to the set sweep length of frequency spectrograph and the analysis bandwidth of FFT, determined that equally the first local oscillator is according to great step value pointwise output frequency in the sweep length scope, " number of scan points=sweep length ÷ fft analysis bandwidth, step value=sweep length ÷ number of scan points ".
The scan mode of described the first local oscillator is to finish by the control system based on ARM.
Beneficial effect: the omnidistance pointwise in scanning process of the utility model the first local oscillator is phase-locked finishes scanning, is sweeping in the situation that wide degree increases, and has improved the frequency accuracy of frequency spectrograph.
Description of drawings
Fig. 1: the theory diagram of open loop scanning in the scanning process;
Fig. 2: the phase-locked theory diagram of pointwise in the scanning process.
Embodiment
The below is described in more detail the utility model.
As shown in Figure 2, the system of the phase-locked realization frequency spectrograph of pointwise full frequency band scanning comprises the first local oscillator, the first frequency mixer, the first amplifier, the first wave filter, the second local oscillator, the second frequency mixer, the second amplifier, the second wave filter, the 3rd local oscillator, three-mixer, Digital IF Processing module;
Radiofrequency signal is delivered to the first frequency mixer and is produced the first intermediate frequency with the first local oscillator mixing after entering the radio-frequency channel, the first intermediate frequency amplify through the first amplifier and the first filter filtering after by the second frequency mixer with generation the second intermediate frequency after itself and the second local oscillator mixing, the second intermediate frequency amplify through the second amplifier and the second filter filtering after by three-mixer with generation the 3rd intermediate frequency after itself and the 3rd local oscillator mixing, radiofrequency signal is finished radio frequency down-conversion through three grades of frequency conversions, and the Digital IF Processing module is used for carrying out digital processing.
The 3rd intermediate frequency, finally carries out data and processes through ADC sampled digital, Digital Down Convert in the Digital IF Processing module in FPGA or DSP, finish spectrum analysis.
Utilize the scanning of the phase-locked realization frequency spectrograph of pointwise full frequency band, the scanning of frequency spectrograph full frequency band realizes by the scanning of the first local oscillator, the sweep limit of the first local oscillator covers the radiofrequency signal input range, scanning is finished in stepping pointwise output under the first local oscillator arranges with different condition, and each Frequency point of exporting in scanning process is in the lock state, and it is phase-locked namely to scan omnidistance pointwise.
The phase-locked stepping of the first local oscillator when scanning pointwise is divided into two kinds of set-up modes according to the Digital IF Processing module to the difference of digital signal processing mode.The digital signal of Digital IF Processing module after to Digital Down Convert is divided into two kinds of processing modes: a kind of is the digital detection mode; Another kind is the FFT(Fast Fourier Transform (FFT)) mode.The selection of dual mode is according to the RBW(resolution bandwidth) setting decide.The intermediate value that resolution bandwidth is set is 1kHz, and the resolution bandwidth that frequency spectrograph is set and 1KHz determine the stepping set-up mode that the first local oscillator pointwise is phase-locked more afterwards.
1. when the set resolution belt of frequency spectrograph is wider than 1KHz, the Digital IF Processing module selects to adopt the mode of digital detection, under the analytical model of digital detection, arranging of sweep length is generally all wider, until full frequency band scanning, the number of scan points of the first local oscillator output is to draw according to frequency spectrograph set sweep length and resolution bandwidth, and the number of scan points in the sweep length scope has determined that the first local oscillator is according to great step value pointwise output frequency.Number of scan points＞sweep length ÷ resolution bandwidth, for the ease of demonstration, usually being fixedly installed is 501,1001,2001 points, step value=sweep length ÷ number of scan points, and＜resolution bandwidth ".
2. when the set resolution bandwidth of frequency spectrograph is less than or equal to 1KHz, the Digital IF Processing module selects to adopt the mode of FFT, under the analytical model of FFT, the setting of sweep length is relatively narrow, until the minimum sweep length 100Hz of frequency spectrograph, the number of scan points of the first local oscillator output is to determine according to the set sweep length of frequency spectrograph and the analysis bandwidth of resolution bandwidth and FFT, has determined that equally the first local oscillator is according to great step value pointwise output frequency in the sweep length scope." number of scan points=sweep length ÷ fft analysis bandwidth, step value=sweep length ÷ number of scan points ".
Under above-mentioned two kinds of different conditions that arrange, no matter the first local oscillator is finished scanning according to which kind of stepping output, each Frequency point of exporting reaches lock-out state, even under the state of full frequency band scanning, the first local oscillator also is the phase-locked output of pointwise.Therefore under any sweep length, the frequency accuracy of frequency spectrograph all is greatly improved.
Carry out the phase-locked scanning of pointwise by control the first local oscillator based on the control system of ARM, after the ARM control system receives the parameters such as the set sweep length of frequency spectrograph, resolution bandwidth, behind more set resolution bandwidth and the intermediate value 1KHz, select to adopt digital detection mode or FFT mode.Adopt subsequently said method to calculate the step value of the first local oscillator output scanning, again according to sweep length, centre frequency and scanning step value calculate the first local oscillator needs the initial frequency of exporting and the frequency that adds up with step value in sweep limit, " initial frequency=centre frequency-sweep length/2 ", again output frequency value is converted to successively the frequency dividing ratio data of First center of percussion frequency divider, successively send to radio-frequency front-end by data bus with the speed more than the 6MHz with binary form, RF front-end module then is responsible for receiving the data that the ARM control system sends by CPLD " programmable logic device (PLD) ", because the ARM control system is transmitted by one group of data bus the control of radio-frequency front-end, so before serial data, distinguished each functional module of radio-frequency front-end with address code, CPLD deciphers address code first before receive data, determines that again should organize data sends to the first local oscillator.In scanning process, by the first local oscillator is sent the output frequency that the frequency dividing ratio data change the first local oscillator.The frequency of pointwise output all is in the state of locking under the effect of phaselocked loop, under the state of full frequency band scanning, the first local oscillator pointwise is phase-locked finishes scanning, because number of scan points is many, the loop bandwidth that improves the first local oscillator can reduce the phase-locked time, eliminate the impact that the phase-locked sweep velocity of bringing of pointwise slows down, guaranteed simultaneously the frequency accuracy of testing under the different bandwidth.
The above is preferred embodiment of the present utility model only, is not restricted to the utility model, and for a person skilled in the art, the utility model can have various modifications and variations.All within spirit of the present utility model and principle, any modification of doing, be equal to replacement, improvement etc., all should be included within the claim scope of the present utility model.
?
Claims (1)
1. the system of the phase-locked realization frequency spectrograph of a pointwise full frequency band scanning comprises the first local oscillator, the first frequency mixer, the second local oscillator, the second frequency mixer, the 3rd local oscillator, three-mixer, Digital IF Processing module; It is characterized in that: also comprise the first amplifier, the first wave filter, the second amplifier, the second wave filter; Radiofrequency signal is delivered to the first frequency mixer and is produced the first intermediate frequency with the first local oscillator mixing after entering the radio-frequency channel, the first intermediate frequency amplify through the first amplifier and the first filter filtering after by the second frequency mixer with generation the second intermediate frequency after itself and the second local oscillator mixing, the second intermediate frequency amplify through the second amplifier and the second filter filtering after by three-mixer with generation the 3rd intermediate frequency after itself and the 3rd local oscillator mixing, radiofrequency signal is finished radio frequency down-conversion through three grades of frequency conversions, and the Digital IF Processing module is used for carrying out digital processing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220568776 CN202870167U (en) | 2012-11-01 | 2012-11-01 | System for realizing spectrum analyzer whole-band scanning by using point-by-point phase locking |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220568776 CN202870167U (en) | 2012-11-01 | 2012-11-01 | System for realizing spectrum analyzer whole-band scanning by using point-by-point phase locking |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202870167U true CN202870167U (en) | 2013-04-10 |
Family
ID=48036876
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220568776 Expired - Lifetime CN202870167U (en) | 2012-11-01 | 2012-11-01 | System for realizing spectrum analyzer whole-band scanning by using point-by-point phase locking |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202870167U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102928664A (en) * | 2012-11-01 | 2013-02-13 | 南京国睿安泰信科技股份有限公司 | System for realizing full-band scanning of frequency spectrograph through point-by-point phase locking |
| CN108303587A (en) * | 2017-01-12 | 2018-07-20 | 北京普源精电科技有限公司 | Improve the spectrum analyzer that bottom is made an uproar |
-
2012
- 2012-11-01 CN CN 201220568776 patent/CN202870167U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102928664A (en) * | 2012-11-01 | 2013-02-13 | 南京国睿安泰信科技股份有限公司 | System for realizing full-band scanning of frequency spectrograph through point-by-point phase locking |
| CN108303587A (en) * | 2017-01-12 | 2018-07-20 | 北京普源精电科技有限公司 | Improve the spectrum analyzer that bottom is made an uproar |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103067104B (en) | System and method for measuring radio-frequency signal high-speed sweeping frequency spectrum based on digital local oscillator | |
| CN102928664A (en) | System for realizing full-band scanning of frequency spectrograph through point-by-point phase locking | |
| CN205829606U (en) | A kind of based on DDS with the frequency synthesizer module of fractional frequency-division phase-locked loop | |
| CN101867381B (en) | Method for realizing down conversion of radio frequency spectrometer by narrow-band local oscillation and switch filtering | |
| CN103248444B (en) | System integration method for test parameters based on unit combination | |
| CN101908896B (en) | Multi-band radio frequency receiver | |
| CN103633997B (en) | TD-LTE-Advanced comprehensive test instrument synthesizes local oscillation device | |
| CN106067815B (en) | Frequency synthesizer based on DDS and fractional frequency division phase-locked loop | |
| US9091724B2 (en) | Synthesizer having adjustable, stable and reproducible phase and frequency | |
| CN107239611B (en) | Vector signal analysis device and method | |
| CN110837002B (en) | Spectrum scanning measuring device and time domain waveform obtaining method | |
| WO2011140563A1 (en) | A signal generator for a built-in self test | |
| CN103134984A (en) | Fast Fourier transform (FFT) broadband frequency spectrometer design based on AD9864 medium frequency digitization system | |
| JP2019504520A (en) | Ultra-low phase noise frequency synthesizer | |
| CN202870167U (en) | System for realizing spectrum analyzer whole-band scanning by using point-by-point phase locking | |
| US7629795B2 (en) | Vector impedance measurement system and method of using same | |
| CN106199184A (en) | A kind of spectrum analyzer with quick phase-locked function | |
| CN106199187A (en) | A kind of method of testing of multi-tone signal relative phase | |
| CN103941092B (en) | A kind of device of the quick scanning survey of frequency domain | |
| CN202856715U (en) | System for realizing spectrum analyzer down-conversion with broadband local oscillators and high-frequency phase demodulation | |
| CN102890192B (en) | Method for realizing scanning of frequency spectrograph under different scanning widths by using multi-local oscillator combination | |
| CN105548932B (en) | Realize the nearly spuious system and method calibrated automatically of microwave test instrument | |
| CN204376873U (en) | For wireless frequency synthesizer | |
| CN102684689B (en) | Direct digital synthesis-based (DDS-based) device and method for synthesizing broadband microwave local-oscillation multi-ring frequency | |
| CN105203976A (en) | Digital MRI radio frequency generator based on DDS and QAM |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130410 |