Novel analog Doppler frequency shift signal generation circuit
By employing two frequency conversions and filtering in the analog Doppler frequency shift signal circuit, the problems of image spurious signals, high local oscillator spurious signals, and sideband spurious signals were solved, achieving high-quality Doppler frequency shift signal generation, simplifying the circuit structure, and improving performance.
Patent Information
- Application Number
- CN202520006902.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-02
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2035-01-02
AI Technical Summary
Traditional analog Doppler frequency shift signal circuits suffer from high image spurious emissions, high local oscillator spurious emissions, high sideband spurious emissions, and excessive use of mixers, making it difficult to meet high-performance requirements.
A novel analog Doppler frequency shift signal generation circuit is designed by employing two frequency conversions and two filterings, reasonably increasing the intermediate frequency signal frequency, and using a bandpass filter to filter out mixing spurious signals.
It generates high-quality Doppler frequency shift signals, reduces image spurious, sideband spurious and local oscillator spurious, avoids overuse of mixers, and achieves simple circuitry and superior performance.
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Figure CN223729726U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to radar technical field, concretely relates to a novel simulation doppler frequency shift signal generating circuit. BACKGROUND
[0002] Simulation doppler frequency shift is an important microwave technology in simulator test equipment, and most of the application scenarios about radar speed measurement will involve doppler frequency shift. In recent years, with the rapid development of radar guidance and radar speed measurement technology, it is particularly important to simulate doppler frequency shift for testing the performance of radar. How to simulate stable and high-quality doppler frequency shift signal is a problem that must be faced and solved by radio frequency engineers and engineering applications.
[0003] At present, there are two kinds of traditional circuit schemes for simulating doppler frequency shift signal, and the first kind is as shown in the figure. Figure 1 The working principle is that: low frequency signal IF (typical power 0dBm, as mixed frequency signal) and high frequency signal LO (typical power 15dBm, as mixed local oscillator signal) are mixed through IQ mixer to obtain the radio frequency signal RF with doppler frequency shift, RF=LO+IF. Therefore, by adjusting the frequency of low frequency signal IF, any frequency of doppler frequency shift can be simulated. The circuit has the advantages of simple implementation method, simple circuit and low cost. But the image rejection of IQ mixer is limited, and the image rejection of conventional IQ mixer is in the order of 20dB, so the simulated signal has a large image spurious, and under typical working conditions, the spurious is in the order of 15-25dBc. Secondly, the local oscillator isolation of IQ mixer is limited, and the local oscillator isolation of conventional IQ mixer is in the order of 40dB, so the simulated signal has a large high frequency local oscillator spurious, and under typical working conditions, the spurious is in the order of 15-25dBc. At the same time, the frequency of low frequency IF signal is very low, generally below 1MHz, and cannot be filtered at RF port, so the simulated signal has a large sideband spurious, and under typical working conditions, the nearest sideband spurious is in the order of 25-35dBc.
[0004] The second kind of traditional circuit scheme for simulating doppler frequency shift signal is as shown in the figure. Figure 2The working principle is that the low frequency signal LO (typical power 15dBm, as a local oscillator signal) and the high frequency signal IF (typical power 0dBm, as an intermediate frequency signal) are mixed by an IQ mixer to obtain a radio frequency signal RF with Doppler frequency shift, RF=LO+IF. Then the RF signal is mixed with the high frequency signal 2 (as a local oscillator signal) to obtain a Doppler frequency shift signal. Therefore, by adjusting the frequency of the low frequency signal LO, a Doppler frequency shift of any frequency can be simulated. The circuit has the advantages of simple implementation method, simple circuit and low cost. However, first, the image rejection of the IQ mixer is limited, and the image rejection of the conventional IQ mixer is in the order of 20dB, so there is a large image spurious in the simulated signal, and under typical working conditions, the spurious is in the order of 15-25dBc. Second, using the low frequency port of the mixer as the local oscillator signal port avoids the problem of high local oscillator spurious, but it is an over-limit use and has a large loss, and under typical working conditions, the loss is in the order of 15dB. At the same time, the frequency of the low frequency LO signal is very low, generally below 1MHz, and cannot be filtered at the RF port, so there is a large sideband spurious in the simulated signal, and under typical working conditions, the nearest sideband spurious is in the order of 25-35dBc.
[0005] In summary, the two conventional circuits have the defects of high image spurious, high local oscillator spurious, high sideband spurious and over-limit use of the mixer, which are difficult to meet the increasingly high performance requirements. Practical new type
[0006] The utility model aims at providing a kind of novel analog Doppler frequency shift signal generation circuit, to solve the problems of high image spurious, high local oscillator spurious, high sideband spurious and over-limit use of the mixer in the prior art analog Doppler frequency shift signal circuit.
[0007] The utility model provides a kind of novel analog Doppler frequency shift signal generation circuit, including high frequency signal input module, mixer one, mixer two, filter module one, filter module two, local oscillator signal input module one, local oscillator signal input module two and radio frequency signal output module;High frequency signal input module is connected with mixer one, and mixer one is connected with filter module one and local oscillator signal input module one respectively, and filter module one is connected with mixer two, and mixer two is connected with filter module two and local oscillator signal input module two respectively, and filter module two is connected with radio frequency signal output module.
[0008] In one embodiment, the high frequency signal input module comprises a high frequency signal input port one, a high frequency signal input port two, an isolator one, an isolator two, a limiter one, a limiter two, a programmable radio frequency switch one and a band pass filter one; the high frequency signal input port one is connected with the isolator one, the limiter one and the programmable radio frequency switch one in sequence, the high frequency signal input port two is connected with the isolator two, the limiter two and the programmable radio frequency switch one in sequence, the programmable radio frequency switch one is connected with the band pass filter one, and the band pass filter one is connected with the mixer one.
[0009] In one embodiment, the local oscillator signal input module one comprises a local oscillator signal input port one, an amplifier one and a band pass filter two; the local oscillator signal input port one is connected with the amplifier one, the band pass filter two and the mixer one in sequence.
[0010] In one embodiment, the filter module one comprises a band pass filter three, a band pass filter four, a chip attenuator one, an amplifier two, a digital controlled attenuator one, a digital controlled attenuator two and a temperature compensating attenuator one; the mixer one, the band pass filter three, the chip attenuator one, the amplifier two, the digital controlled attenuator one, the digital controlled attenuator two, the temperature compensating attenuator one, the band pass filter four and the mixer two are connected in sequence.
[0011] In one embodiment, the filter module two comprises a band pass filter six, a chip attenuator two and a band pass filter seven; the mixer two, the band pass filter six, the chip attenuator two, the band pass filter seven and the radio frequency signal output module are connected in sequence.
[0012] In one embodiment, the local oscillator signal input module two comprises a local oscillator signal input port two, an amplifier three and a band pass filter five; the local oscillator signal input port two, the amplifier three, the band pass filter five and the mixer two are connected in sequence.
[0013] In one embodiment, the radio frequency signal output module comprises a programmable radio frequency switch two, a radio frequency signal output port one and a radio frequency signal output port two; the band pass filter seven is connected with the programmable radio frequency switch two, and the programmable radio frequency switch two is connected with the radio frequency signal output port one and the radio frequency signal output port two respectively.
[0014] In one embodiment, the high frequency signal input module is a high frequency signal input port, and the radio frequency signal output module is a radio frequency signal output port.
[0015] In one embodiment, the filter module one and the filter module two are both band pass filters.
[0016] In one embodiment, the local oscillator signal input module one is a first local oscillator signal input port, and the local oscillator signal input module two is a second local oscillator signal input port.
[0017] The utility model discloses beneficial effect lies in: the utility model discloses through the mode of reasonable improvement intermediate frequency signal frequency, make the frequency difference of mixed frequency spurious signal from useful signal increase, with the purpose of filtering mixed frequency spurious through band pass filter, finally produce high quality doppler frequency shift signal. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 The utility model discloses background art first kind traditional analog doppler frequency shift signal circuit.
[0019] Figure 2 The utility model discloses background art second kind traditional analog doppler frequency shift signal circuit.
[0020] Figure 3 The utility model discloses embodiment 1 new analog doppler frequency shift signal generation circuit.
[0021] Figure 4 The utility model discloses embodiment 2 high frequency signal input module circuit diagram.
[0022] Figure 5 The utility model discloses embodiment 2 local oscillator signal input module one circuit diagram.
[0023] Figure 6 The utility model discloses embodiment 2 filter module one circuit diagram.
[0024] Figure 7 The utility model discloses embodiment 2 filter module two circuit diagram.
[0025] Figure 8 The utility model discloses embodiment 2 local oscillator signal input module two circuit diagram.
[0026] Figure 9 The utility model discloses embodiment 2 radio frequency signal output module circuit diagram. DETAILED DESCRIPTION
[0027] In order to make the technical problem of the present application, technical scheme and beneficial effect more clearly, the following will be further described in detail with the drawings and examples.The specific examples described here are only used to explain the present application, and are not used to limit the present application.
[0028] Embodiment 1
[0029] In order to solve the problem of the mirror image spurious of analog doppler frequency shift signal circuit, local oscillator spurious, sideband spurious and the problem of using frequency mixer beyond limit in prior art, the utility model discloses a kind of new analog doppler frequency shift signal generation circuit, as shown in Figure 3The high frequency signal input port, the first local oscillator signal input port are connected with the first mixer respectively, the first mixer is connected with the second mixer through the first band-pass filter, the second mixer is connected with the second local oscillator signal input port and the second band-pass filter respectively, and the second band-pass filter is connected with the radio frequency signal output port.
[0030] The high frequency signal input port is used for inputting high frequency signal RF1, the first local oscillator signal input port is used for inputting local oscillator signal LO1, the first mixer mixes the high frequency signal RF1 and the local oscillator signal LO1 to obtain intermediate frequency signal IF=RF1-LO1. The frequency of the intermediate frequency signal IF is relatively high, and a suitable intermediate frequency frequency can be formulated according to actual requirements. In this example, the first band-pass filter is used to filter the spurs caused by mixing. The second local oscillator signal input port is used for inputting local oscillator signal LO2, and the second mixer mixes the local oscillator signal LO2 and the intermediate frequency signal IF filtered by the second band-pass filter to obtain radio frequency signal RF2 through the radio frequency signal output port, and RF2=LO2+IF. The local oscillator signal LO2 in this example is set as LO2=LO1+△F. Since IF=RF1-LO1 and LO2=LO1+△F, RF2=RF1+△F. The △F is an analog generated Doppler shift, and by changing the value of △F, a Doppler shift of any frequency can be obtained.
[0031] In summary, the scheme filters out the spurs caused by mixing through twice mixing and twice filtering, and simulates a Doppler shift of any frequency by controlling the frequency of △F. In this example, the frequency difference between the mixed spur signal and the useful signal is increased by reasonably increasing the intermediate frequency signal frequency, so as to filter out the mixed spur through the band-pass filter, and finally a high-quality Doppler shift signal is generated. This example overcomes the defects of the two traditional circuits, that is, each has its own advantages and disadvantages. The advantages of simple circuit, high image spur suppression, high local oscillator spur suppression, no edge spur, and no out-of-limit component usage are taken into account.
[0032] Embodiment 2
[0033] At present, a new type of radio frequency analog component needs to generate a Doppler shift signal, and the requirements of the Doppler frequency signal for image suppression, local oscillator suppression and edge suppression are relatively high, and the traditional circuit cannot meet the requirements. The application of the present application to the new type of radio frequency analog component has the advantages of high quality of simulating Doppler shift signal, high spur suppression, controllable frequency shift frequency and simple implementation. Specific applications are as shown in the following table. Figures 4 to 9
[0034] The high frequency signal input port one RFin1 is connected with the isolator one, the amplitude limiter one and the program-controlled radio frequency switch one in sequence, the high frequency signal input port two RFin2 is connected with the isolator two, the amplitude limiter two and the program-controlled radio frequency switch one SP2T1 in sequence, the program-controlled radio frequency switch one SP2T1 is connected with the band-pass filter one, and the band-pass filter one is connected with the mixer one. The local oscillator signal input port one L01 is connected with the amplifier one, the band-pass filter two and the mixer one in sequence. The mixer one, the band-pass filter three, the chip attenuator one, the amplifier two, the numerical control attenuator one, the numerical control attenuator two, the temperature compensation attenuator one, the band-pass filter four and the mixer two are connected in sequence. The local oscillator signal input port two L02, the amplifier three, the band-pass filter five and the mixer two are connected in sequence. The mixer two, the band-pass filter six, the chip attenuator two, the band-pass filter seven and the program-controlled radio frequency switch two SP2T2 are connected in sequence, and the program-controlled radio frequency switch two SP2T2 is connected with the radio frequency signal output port one RFOUT1 and the radio frequency signal output port two RFOUT2 respectively.
[0035] After the argument of the example and a series of experimental verification, it is proved that the quality of the Doppler frequency shift signal simulated by the radio frequency simulation assembly of the Doppler frequency shift signal generation circuit is high, the spurious suppression degree is high, the frequency shift frequency is controllable, and the implementation is simple and convenient. The technical indexes reached by the radio frequency simulation assembly are as shown in Table 1:
[0036] Table 1: Technical indexes reached by the radio frequency simulation assembly
[0037]
[0038] The technical features of the above embodiments can be combined in any manner. In order to make the description simple, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the description.
[0039] The above-described embodiments only express several implementation manners of the application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which are within the protection scope of the application. Therefore, the patent protection scope of the application should be subject to the appended claims.
Claims
1. A novel analog Doppler frequency shift signal generation circuit, characterized in that, It includes a high-frequency signal input module, mixer one, mixer two, filter module one, filter module two, local oscillator signal input module one, local oscillator signal input module two, and radio frequency signal output module; the high-frequency signal input module is connected to mixer one, mixer one is connected to filter module one and local oscillator signal input module one respectively, filter module one is connected to mixer two, mixer two is connected to filter module two and local oscillator signal input module two respectively, and filter module two is connected to radio frequency signal output module.
2. The novel analog Doppler frequency shift signal generation circuit according to claim 1, characterized in that, The high-frequency signal input module includes a high-frequency signal input port one, a high-frequency signal input port two, an isolator one, an isolator two, a limiter one, a limiter two, a programmable radio frequency switch one, and a bandpass filter one. The high-frequency signal input port one is connected in sequence to the isolator one, the limiter one, and the programmable radio frequency switch one. The high-frequency signal input port two is connected in sequence to the isolator two, the limiter two, and the programmable radio frequency switch one. The programmable radio frequency switch one is connected to the bandpass filter one, and the bandpass filter one is connected to the mixer one.
3. The novel analog Doppler frequency shift signal generation circuit according to claim 2, characterized in that, The local oscillator signal input module includes a local oscillator signal input port, an amplifier, and a bandpass filter; the local oscillator signal input port is connected in sequence to the amplifier, the bandpass filter, and the mixer.
4. The novel analog Doppler frequency shift signal generation circuit according to claim 3, characterized in that, The filtering module one includes a bandpass filter three, a bandpass filter four, a chip attenuator one, an amplifier two, a digitally controlled attenuator one, a digitally controlled attenuator two, and a temperature-compensated attenuator one; the mixer one, the bandpass filter three, the chip attenuator one, the amplifier two, the digitally controlled attenuator one, the digitally controlled attenuator two, the temperature-compensated attenuator one, the bandpass filter four, and the mixer two are connected in sequence.
5. A novel analog Doppler frequency shift signal generation circuit according to claim 4, characterized in that, The second filtering module includes a bandpass filter six, a chip attenuator two, and a bandpass filter seven. The second mixer, the sixth bandpass filter, the second chip attenuator two, the seventh bandpass filter, and the RF signal output module are connected in sequence.
6. A novel analog Doppler frequency shift signal generation circuit according to claim 5, characterized in that, The local oscillator signal input module two includes a local oscillator signal input port two, an amplifier three, and a bandpass filter five; the local oscillator signal input port two, the amplifier three, the bandpass filter five, and the mixer two are connected in sequence.
7. A novel analog Doppler frequency shift signal generation circuit according to claim 6, characterized in that, The radio frequency signal output module includes a programmable radio frequency switch two, a radio frequency signal output port one, and a radio frequency signal output port two; the bandpass filter seven is connected to the programmable radio frequency switch two, and the programmable radio frequency switch two is connected to both the radio frequency signal output port one and the radio frequency signal output port two.
8. A novel analog Doppler frequency shift signal generation circuit according to claim 1, characterized in that, The high-frequency signal input module is a high-frequency signal input port; the radio frequency signal output module is a radio frequency signal output port.
9. A novel analog Doppler frequency shift signal generation circuit according to claim 8, characterized in that, Both filter module one and filter module two are bandpass filters.
10. A novel analog Doppler frequency shift signal generation circuit according to claim 9, characterized in that, The first local oscillator signal input module is the first local oscillator signal input port, and the second local oscillator signal input module is the second local oscillator signal input port.