Broadband reconfigurable comb line spectrum dot frequency extraction system and method

Abstract

The invention discloses a broadband reconfigurable comb line spectrum dot frequency extraction system and method, and belongs to the technical field of microwave frequency synthesis. The method comprises the following steps: firstly, converting a multi-harmonic signal generated by a comb spectrum generator into a certain frequency band, taking out a required high-frequency dot frequency signal corresponding to a certain harmonic dot frequency signal through a high-suppression narrow-band dot frequency filter, and then down-converting the taken-out high-frequency dot frequency signal back to the original harmonic dot frequency by using a frequency mixer and a coherent local oscillator signal; therefore, the extraction of a certain point frequency signal required in the multi-harmonic signal output by the comb line spectrum generator is realized, and the circuit can realize the extraction of a plurality of different harmonic point frequencies by setting different coherent local oscillator signal frequencies.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave frequency synthesis, and relates to a method for extracting a multi-harmonic signal output by a comb spectrum generator by using a mixer and a coherent local oscillator signal, and specifically relates to a broadband reconfigurable comb spectrum point frequency extraction system and method. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] The point frequency extraction technology of the comb spectrum generator output is a frequency synthesis technology widely used in the field of direct frequency synthesis. Its purpose is to extract one or more required high-purity point frequency signals for frequency synthesis from the numerous harmonic signals output by the comb spectrum generator. Currently, the most widely used and mature extraction technology is to customize the design of corresponding high-suppression filters or switching filter groups according to the frequency and number of the signal points to be extracted for filtering extraction. There are two typical technical solutions according to the number of extracted point frequency signals.

[0004] (a) Single point frequency extraction technology The typical single comb line spectrum harmonic frequency extraction technology mainly designs a narrowband, high-suppression bandpass filter based on the frequency of a certain harmonic point to be extracted and the frequency interval of the harmonic signal (i.e. the fundamental frequency). In order to achieve high suppression of other unnecessary harmonic frequencies while extracting the required frequency point, a multi-stage filter cascade is usually required to achieve this. The basic principle of the typical single comb line spectrum harmonic frequency extraction circuit can be found in Figure 2 shown.

[0005] Figure 2 In the single point frequency signal extraction circuit shown in the figure, the input signal of the comb spectrum generator is , its output signal contains and its many harmonic signals 、 … 、 、 etc., it is necessary to extract a certain harmonic frequency signal (such as ), the current typical technical solution is to customize the design of the passband center frequency The narrowband high suppression filter extracts the required harmonics from the numerous harmonic signals. Signals, and because the out-of-band suppression capability of a single-stage filter is limited (usually only around 35dB), multiple identical filters are often required to be cascaded to enhance the suppression capability of out-of-band signals in order to meet the at least 60dBc suppression capability required for frequency synthesis. When using a multi-stage filter cascade, considering the matching between filters, it is usually necessary to add attenuation isolation, amplifier isolation and other measures to maximize the out-of-band suppression enhancement effect of the multi-stage filter cascade.

[0006] (b) Multi-harmonic frequency extraction technology Typical multi-harmonic frequency extraction technology can be found in Figure 3 This solution is similar to the single-frequency extraction solution, except that multiple sets of narrowband filters corresponding to the passband center frequency are customized and designed based on the number and frequency of the harmonic frequencies to be extracted. At the same time, a single-pole multi-throw switch is used to combine multiple sets of filters to form a switch filter bank. By controlling the front and rear single-pole multi-throw switches to select different filter branches and the corresponding point frequency signal, the arbitrary selection of multiple harmonic frequencies can be achieved.

[0007] The above typical solutions have obvious advantages and disadvantages: Advantages: The design is clear and simple, and the extraction of each corresponding frequency point is achieved entirely by relying on the suppression capability of the corresponding filter at each frequency point. No other spurious signals unrelated to the original signal are introduced into the circuit.

[0008] Disadvantages: The circuit is bulky and completely customized.

[0009] 1. The circuit is designed with the same number of filter channels according to the number of frequency points to be extracted, and each channel requires a multi-stage filter cascade to achieve the extraction of each frequency point and high out-of-band suppression. When there are multiple frequency points, a single-pole multi-throw switch is also required. It is even necessary to add a single-pole single-throw switch to achieve the switching and isolation of multiple extracted signals, resulting in a large circuit. The more frequency points there are, the larger the volume.

[0010] 2. Each channel filter in the circuit is completely customized according to the extracted frequency point. Once the required frequency point changes, this circuit cannot be used and the filter needs to be redesigned. It is completely customized and lacks versatility and scalability.

[0011] 3. The filter sizes, implementation methods, and processes corresponding to different frequency bands are different, which increases the design difficulty, makes it impossible to solidify the processing and debugging procedures, leads to poor consistency, and lacks reconfigurability.

[0012] In summary, practical engineering applications require a universal comb spectrum point frequency extraction circuit with a simple solution, fixed circuit form, and reconfigurable expansion within a wide frequency band to improve product design efficiency. Summary of the Invention

[0013] The purpose of the present invention is to address the problems existing in the prior art and provide a broadband reconfigurable comb spectrum point frequency extraction system and method. The method of extracting multiple harmonic frequencies is flexible and reconfigurable (different frequency points can be extracted simply by changing the coherent local oscillator frequency). There is no need to specially customize the design of filters or switch filter groups. Different point frequency signals can be arbitrarily extracted within a certain frequency band, thus solving the above-mentioned problems.

[0014] Generally speaking, the present invention first converts the multi-harmonic signal generated by the comb spectrum generator to a certain frequency band, extracts the high-frequency point frequency signal corresponding to a required harmonic point frequency signal through a high-suppression narrowband point frequency filter, and then uses a mixer and a coherent local oscillator signal to down-convert the extracted high-frequency point frequency signal back to the original harmonic point frequency frequency, thereby realizing the extraction of a required point frequency signal from the multi-harmonic signal output by the comb spectrum generator. In addition, this circuit can realize the extraction of multiple different harmonic point frequencies by setting different coherent local oscillator signal frequencies.

[0015] Specifically, the specific technical solutions of the present invention are as follows: A broadband reconfigurable comb spectrum point frequency extraction system, comprising: Comb spectrum generator, which multiplies the input signal and outputs multi-harmonic signals; A first mixer, whose input port is connected to the output end of the comb spectrum generator, is used to up-mix the multi-harmonic signal with the coherent local oscillator signal to generate a mixed signal; a narrowband frequency filter connected to the output end of the first mixer and used for extracting the frequency signal from the mixed signal; The second mixer has an input port connected to the output end of the narrowband frequency filter, and is used to down-mix the frequency signal with the coherent local oscillator signal, shift the frequency signal spectrum back to the original frequency of the signal, and complete the extraction of the frequency signal; A voltage-controlled oscillator, the output end of which is connected to the local oscillator ports of the first mixer and the second mixer respectively through a power divider, for providing a coherent local oscillator signal with adjustable frequency and consistent phase; The control module is connected to the voltage-controlled oscillator and is used to calculate and configure the frequency value of the coherent local oscillator signal according to the frequency of the point frequency signal, so that the point frequency signal to be extracted falls within the passband range of the narrowband point frequency filter after up-mixing, and is restored to the original frequency after down-mixing.

[0016] Furthermore, the passband center frequency of the narrowband frequency filter is fixed, and the passband bandwidth of the narrowband frequency filter is less than 1 / 4 of the input signal frequency.

[0017] Furthermore, when the frequency deviates from the narrowband point frequency filter passband center frequency, It has a suppression capability of more than 60dB.

[0018] Furthermore, the frequency error or fluctuation range of the coherent local oscillator signal output by the coherent local oscillator signal source does not exceed that of the narrow-band point frequency filter.

[0019] Furthermore, the control module includes: a DA and an operational amplifier circuit.

[0020] Furthermore, it also includes: A first low-pass filter is provided between the comb spectrum generator and the first mixer, and is used to filter out high-order harmonic signals that do not need to be extracted from the multi-harmonic signal; The second low-pass filter has an input port connected to the output end of the second mixer, and is used to filter out other intermodulation components after down-mixing and output the extracted point frequency signal.

[0021] The present invention also proposes a broadband reconfigurable comb line spectrum point frequency extraction method, comprising: Step S1: Determine the voltage controlled oscillator output signal frequency; Step S2: Use a power divider to divide the output signal The equal-phase power is divided into two paths and transmitted to the first mixer and the second mixer respectively as the coherent local oscillator signals of the two mixers; Step S3: Using the first mixer and the coherent local oscillator signal Mixing the spectrum of the multi-harmonic signal to be extracted to obtain a mixed signal; Step S4: extracting a frequency signal from the mixed signal through a narrowband frequency filter; Step S5: Using the second mixer and the coherent local oscillator signal The frequency spectrum of the point frequency signal is moved and restored to the original frequency of the signal to complete the extraction of the point frequency signal.

[0022] Furthermore, the step S1 includes: calculate hour The frequency value controls the DA and operational amplifier circuit outputs corresponding The voltage-controlled voltage VT of the frequency value is tuned to output the corresponding frequency of the voltage-controlled oscillator. Signal.

[0023] Furthermore, it also includes: Before up-mixing in step S3, a first low-pass filter is used to filter out higher harmonic signals that do not need to be extracted from the multi-harmonic signal; After down-mixing in step S5, other intermodulation components after down-mixing are filtered out using a second low-pass filter, and the extracted point frequency signal is output.

[0024] Compared with the existing technology, the beneficial effects of the present invention are: 1. Compared with the traditional method that requires customized design of filters or multi-way switching filter groups of corresponding frequencies according to the extracted harmonic point frequency signals, the present invention is flexible and reconfigurable in extracting multiple harmonic frequencies (different frequency points can be extracted by simply changing the coherent local oscillator frequency). There is no need to specially customize the design of filters or switching filter groups. Different point frequency signals can be arbitrarily extracted within a certain frequency band. Compared with the traditional customized switching filter group method, the entire circuit is smaller in size, the number and frequency of extracted points can be reconstructed by digital control, the design and use are more flexible, and the integrated design is convenient.

[0025] 2. Based on the analysis of the advantages and disadvantages of the traditional comb spectrum generator point frequency extraction circuit in direct frequency synthesis, the present invention uses a mixer and a coherent local oscillator signal to first up-mix the broadband harmonic point frequency signal output by the comb spectrum generator to a fixed intermediate frequency, and then uses a narrowband filter with a fixed passband frequency to extract the intermediate frequency point frequency signal corresponding to the up-mixed harmonic point frequency signal, and then uses the coherent local oscillator signal and the mixer to down-mix the extracted intermediate frequency point frequency signal to the original frequency value of the harmonic point frequency signal to be extracted. During this process, the entire hardware circuit remains unchanged, and only the frequency value of the coherent local oscillator signal is controlled by software (such as controlling the DA output voltage and tuning the VCO to output different frequencies) to achieve the extraction of different point frequency signals in the broadband multi-harmonic point frequency signal output by the comb spectrum generator.

[0026] 3. The hardware circuitry of the present invention is simple and reconfigurable. By calculating and adjusting the frequency of the coherent local oscillator signal, the different harmonic frequency signals to be extracted are mixed into a fixed intermediate frequency filter for extraction, and then mixed back to the original harmonic frequency. Throughout this process, the filters, mixers, oscillators, and other hardware circuits are fixed and reused. Within a certain bandwidth, multiple harmonic frequency points can be extracted by simply changing the output signal frequency of the voltage-controlled oscillator through software control. The number of harmonics extracted is independent of the hardware. Furthermore, the voltage-controlled oscillator output frequency interface can be reconfigured and calculated for harmonic signals with different frequency intervals, without requiring any hardware changes.

[0027] 4. The circuit of the present invention is small in size and has good signal isolation and suppression. The harmonic point frequency signal has only one link: up-mixing - point frequency filtering - down-mixing, and only a high-suppression intermediate frequency narrowband filter needs to be designed. Compared with the traditional multi-branch form of the switching filter group, the circuit of the present invention has a fixed circuit size and a small size, and there is no need to worry about the change of filter size as the extracted spectrum changes. At the same time, there is no signal radiation leakage between multiple filter branches, which leads to poor suppression of other frequency points after point frequency extraction. The signal isolation design is simpler and the out-of-band suppression degree will be higher.

[0028] 5. Easy circuit expansion: The range of harmonic frequency signals extracted in this invention is primarily determined by the output frequency range of the voltage-controlled oscillator, while the lower limit of the harmonic frequency interval is primarily determined by the cutoff frequency of the intermediate frequency filter. Therefore, when the range of harmonic frequencies to be extracted changes, it is sufficient to simply calculate and replace the voltage-controlled oscillator that can output the corresponding frequency band. If the frequency interval of the extracted harmonic frequencies changes significantly, the corresponding filter can be expanded and replaced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a circuit diagram of a broadband reconfigurable comb spectrum point frequency extraction circuit; Figure 2 This is the principle block diagram of the single point frequency output extraction circuit of a typical comb spectrum generator; Figure 3 This is a block diagram of the principle of a typical multi-harmonic frequency extraction technology; Figure 4 An example implementation for tuning voltage amplification; Figure 5 Schematic diagram of the overall circuit of the implementation example. DETAILED DESCRIPTION

[0030] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0031] The present invention is a method of utilizing a coherent local oscillator signal The first mixer first converts the broadband multi-harmonic signal output by the comb spectrum generator ( ) Spectrum moved to a fixed intermediate frequency After the frequency band, use a passband frequency (like ) Fixed narrowband high suppression bandpass filter (can be cascaded in multiple stages) to achieve the point frequency signal in the intermediate frequency band After the extraction is completed, the coherent local oscillator signal is used The second mixer moves the extracted frequency spectrum to the original frequency ( ), the two spectrum shifting processes are one up-mixing and one down-mixing, and the local oscillator used is a coherent local oscillator, so the harmonic point frequency signal to be extracted After the spectrum is shifted twice by up-mixing and down-mixing, it returns to the original frequency value. , and the local oscillator signals cancel each other out in the two mixings, and only the harmonic point frequency signal that needs to be extracted is left. .

[0032] In the circuit of the present invention, the coherent local oscillator signal can be generated by a broadband voltage-controlled oscillator, a broadband integrated phase-locked loop, etc. Therefore, when all hardware circuits such as the filter, mixer, and coherent local oscillator remain unchanged, the coherent local oscillator signal can be generated by changing the coherent local oscillator signal. The frequency value of can realize the extraction of different harmonic frequency point frequency signals, such as setting It can realize Harmonic point frequency signal extraction. Therefore, within the frequency bandwidth of the entire local oscillator signal, multiple harmonic point frequency signals can be extracted by configuring different local oscillator frequencies, realizing broadband reconstructible extraction of the multi-harmonic point frequency signal output by the comb spectrum generator. Theoretically, the maximum number of extractable frequency points is , is the bandwidth of the local oscillator output signal.

[0033] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0034] Example 1 See also Figure 1 , a broadband reconfigurable comb spectrum point frequency extraction system, comprising: Comb spectrum generator, which multiplies the input signal and outputs multi-harmonic signals; A first low-pass filter is provided between the comb spectrum generator and the first mixer, and is used to filter out high-order harmonic signals that do not need to be extracted from the multi-harmonic signal; a first mixer, whose input port is connected to the output end of the first low-pass filter, and is used to up-mix the multi-harmonic signal with the coherent local oscillator signal to generate a mixed signal; a narrowband frequency filter connected to the output end of the first mixer and used for extracting the frequency signal from the mixed signal; The second mixer has an input port connected to the output end of the narrowband frequency filter, and is used to down-mix the frequency signal with the coherent local oscillator signal, shift the frequency signal spectrum back to the original frequency of the signal, and complete the extraction of the frequency signal; A second low-pass filter, whose input port is connected to the output end of the second mixer, is used to filter out other intermodulation components after down-mixing and output the extracted point frequency signal; A voltage-controlled oscillator, the output end of which is connected to the local oscillator ports of the first mixer and the second mixer respectively through a power divider, for providing a coherent local oscillator signal with adjustable frequency and consistent phase; The control module is connected to the voltage-controlled oscillator and is used to calculate and configure the frequency value of the coherent local oscillator signal according to the frequency of the point frequency signal, so that the point frequency signal to be extracted falls within the passband range of the narrowband point frequency filter after up-mixing and is restored to the original frequency after down-mixing; the control module includes: a DA and an operational amplifier circuit.

[0035] In this embodiment, it should be noted that the comb spectrum generator has the following features: 1. Input signal Perform frequency multiplication and output the 1st to Nth harmonic signals corresponding to the input signal ( ); 2. The output harmonic signal power decreases as the harmonic order increases.

[0036] In this embodiment, it should be noted that the first low-pass filter has the following characteristics: 1. Suppress signals with a frequency greater than the cutoff frequency, and pass signals with a frequency less than the cutoff frequency with low insertion loss; 2. Design the cutoff frequency according to circuit requirements to suppress unnecessary high-order harmonic signals.

[0037] In this embodiment, it should be noted that the first mixer has the following characteristics: 1. Use the coherent local oscillator signal output by the power divider to move the spectrum of the multi-harmonic signal to be extracted to the high and medium frequency band; 2. The mixer has high intermodulation suppression capability; 3. Reasonably set the coherent local oscillator signal frequency according to the multi-harmonic signal frequency band.

[0038] In this embodiment, it should be noted that the narrowband point frequency filter has the following characteristics: 1. It is a bandpass filter with a narrow passband width and a fixed passband center frequency, which is usually required to be less than 1 / 4 of the frequency of the comb spectrum input signal; 2. Strong out-of-band suppression capability; 3. Small size and easy to use in multi-stage cascade, preferably using narrow-band high-suppression bandpass filter with FBAR process.

[0039] 4. In order to ensure the high suppression ability of the narrowband point frequency filter on the signal that does not need to be extracted, the filter should be placed around the center frequency of the passband. In order to take into account the passband bandwidth, insertion loss, size, etc., it is usually necessary to cascade multiple filters and amplifiers.

[0040] In this embodiment, it should be noted that the second mixer has the following characteristics: 1. Use the coherent local oscillator signal that is coherent with the first mixer to shift the frequency spectrum of the point frequency signal extracted by the point frequency filter back to the original frequency of the signal.

[0041] 2. The mixer has high intermodulation suppression capability; 3. The mixed output needs to use a low-pass filter to filter out high-order intermodulation.

[0042] In this embodiment, it should be noted that the second low-pass filter has the following characteristics: 1. Suppress signals with a frequency greater than the cutoff frequency, and pass signals with a frequency less than the cutoff frequency with low insertion loss; 2. Design the cutoff frequency according to the intermodulation product frequency output by the second mixer to suppress the higher-order intermodulation products output by the mixer.

[0043] In this embodiment, it should be noted that the power divider has the following characteristics: The input local oscillator signal is distributed and output with equal phase and equal power to ensure that the two local oscillator signals input to the first mixer and the second mixer are coherent.

[0044] In this embodiment, it should be noted that the voltage controlled oscillator (VCO) has the following characteristics: 1. It can output a sine wave signal of corresponding frequency according to the given tuning voltage value; 2. Capable of fast frequency tuning; 3. The tuning voltage can be generated by DA and active filter amplifier circuit to achieve digital controllable configuration; 4. The output signal frequency range is wide.

[0045] In this embodiment, in order to ensure that the harmonic signal to be extracted and the coherent local oscillator signal can fall within the passband frequency of the narrowband frequency filter after mixing in the first mixer, it is necessary to ensure that the VT voltage corresponds to the tuned output. The signal frequency error or fluctuation range does not exceed the passband bandwidth of the point frequency filter.

[0046] Example 2 Example 2 Based on the broadband reconfigurable comb line spectrum point frequency extraction system proposed in Example 1, a broadband reconfigurable comb line spectrum point frequency extraction method is proposed.

[0047] First, define the input signal frequency of the comb spectrum generator as , the output harmonic signal frequency is The passband center frequency of the narrowband point frequency filter is fixed at , the cutoff frequency is around At the frequency, the voltage controlled oscillator tuned output signal frequency is .

[0048] See also Figure 1 A broadband reconfigurable comb spectrum point frequency extraction method specifically comprises the following steps: 1. Determine the voltage controlled oscillator output signal frequency; That is, calculation hour The frequency value controls the DA and operational amplifier circuit outputs corresponding The voltage-controlled voltage VT of the frequency value is tuned to output the corresponding frequency of the voltage-controlled oscillator. Signal.

[0049] 2. Use a power splitter to output the signal The equal-phase power is divided into two paths and transmitted to the first mixer and the second mixer respectively using two cables of equal length to serve as the coherent local oscillator signals of the two mixers.

[0050] 3. Use the first low-pass filter to filter out the high-order harmonic signals that do not need to be extracted from the multi-harmonic signal, and the harmonic signal frequency that needs to be extracted can pass through with low loss; 4. Use the first mixer and the coherent local oscillator signal Mixing the spectrum of the multi-harmonic signal to be extracted to obtain a mixed signal; That is, using the first mixer and the coherent local oscillator signal The broadband multi-harmonic signal to be extracted Spectrum upmixing moved to ~ In this frequency band, the mixing process uses a high local oscillator up-mixing mode to reduce intermodulation products.

[0051] 5. Extract the frequency signal from the mixed signal through a narrowband frequency filter; That is, the narrowband point frequency filter ~ The frequency extracted from the frequency band signal is signal and suppress other frequency signals.

[0052] 6. Use a second mixer and a coherent local oscillator signal Move the frequency spectrum of the point frequency signal back to the original frequency of the signal to complete the extraction of the point frequency signal; That is, the second mixer and the coherent local oscillator signal The narrowband point frequency filter extracts After the signal is mixed, The signal spectrum is down-mixed and moved to Department ( , high LO mode).

[0053] 7. Use the second low-pass filter to filter out other intermodulation components after down-mixing and output the extracted point frequency signal; Repeat 1 to 7 above, and calculate hour The frequency value controls the voltage controlled oscillator to output the corresponding frequency signal, and realize different harmonic signals in turn 、 ...etc.

[0054] Example 3 See also Figure 1-5 Circuit design was performed based on the broadband reconfigurable comb spectrum point frequency extraction method described in the above embodiment. The device's peripheral configuration circuits can be built based on the device manual and the reference circuits provided by the manufacturer, and will not be described in detail. The following mainly describes four aspects: the selection of key components, key signals and their connection to the device, the operating process, and test results.

[0055] 1. Device selection a) The first and second mixers use broadband mixers with an RF / LO operating frequency range of 6 to 18 GHz and an IF operating frequency range of 0.1 to 6 GHz. The conversion loss is typically 10 dB, and the LO to RF / IF isolation is greater than 30 dB.

[0056] b) The output frequency of the voltage controlled oscillator is 4 to 8 GHz, and the tuning voltage is 0 to 22 V.

[0057] c) Using an operational amplifier to build a tuned voltage operational amplifier circuit Figure 4 .

[0058] d) The first low-pass filter and the second low-pass filter are self-made or use mature commercial devices according to the frequency band. In this example, the corresponding low-pass filter is selected according to the highest frequency of the harmonic to be extracted.

[0059] e) Narrowband point-frequency filters can be homemade or use mature commercial components based on requirements such as passband frequency and out-of-band suppression. In this example, an Fbar filter is selected, which has a passband center frequency of 3200 MHz, a passband bandwidth of 20 MHz, a suppression of ≥30 dBc at a point 100 MHz away from the center frequency, and an insertion loss of ≤3 dB.

[0060] f) The power divider is a homemade part.

[0061] g) DA uses a 12-bit DAC function core integrated in the microcontroller.

[0062] h) The 100MHz comb spectrum generator is a self-made component, which inputs 100MHz and outputs 100MHz comb spectrum signals in the range of 100M~2000MHz.

[0063] 2. Key signals and connections with devices a) The 100MHz / 200MHz / … / 2000MHz comb spectrum harmonic frequency signals output by the comb spectrum generator are connected to the first low-pass filter for filtering and then output 100MHz / 200MHz / … / 1700MHz frequency signals.

[0064] b) The 100MHz / 200MHz / … / 1700MHz frequency signal is connected to the IF port of the second mixer, and the coherent local oscillator signal output by the power divider is connected to the LO port of the mixer.

[0065] c) The DA outputs a 0.2V voltage, which is amplified to 0.8V by the operational amplifier circuit and outputted at RFOUT (pin 15) of the tuned voltage-controlled oscillator. After power division, the signal becomes two coherent local oscillator signals.

[0066] d) The 100MHz / 200MHz / … / 1700MHz frequency signals are mixed with the local oscillator signal by the first mixer and then output 2300MHz / 2400MHz / … / 3900MHz and other intermodulation signals. After these signals are filtered by the three-stage FBAR frequency filter, the 3200MHz frequency signal is extracted and other signals are suppressed. Figure 4 shown.

[0067] e) The extracted 3200MHz frequency signal enters the RF port of the second mixer and outputs the power divider After the coherent local oscillator signal is down-mixed, an 800MHz point frequency signal and other intermodulation products are generated.

[0068] f) The output 800MHz frequency signal and other intermodulation components are filtered by LFCN-1700, which suppresses the intermodulation components and extracts the 800MHz frequency signal.

[0069] g) Adjust the DA output voltage gradually, amplify it to the output through the operational amplifier circuit, and tune the voltage-controlled oscillator RFOUT (pin 15) to output in sequence signal, and finally extract the 800MHz / 900MHz / … / 1700MHz frequency signals in sequence.

[0070] The completed circuit (excluding peripheral circuits not related to the patent idea) is shown in Figure 5 .

[0071] 3. Working process The working process of the implementation example is described as follows. By default, the control method given in the device manual is used to control each device.

[0072] a) The 100MHz / 200MHz / … / 2000MHz comb spectrum harmonic frequency signals output by the comb spectrum generator are connected to the first low-pass filter and filtered to output 100MHz / 200MHz / … / 1700MHz frequency signals.

[0073] b) The 100MHz / 200MHz / … / 1700MHz frequency signal is connected to the IF port of the second mixer, and the coherent local oscillator signal output by the power divider is connected to the LO port of the mixer.

[0074] c) The DA outputs a 0.2V voltage, which is amplified to 0.8V by the operational amplifier circuit and outputted at RFOUT (pin 15) of the tuned voltage-controlled oscillator. After power division, the signal becomes two coherent local oscillator signals.

[0075] d) 100MHz / 200MHz / … / 1700MHz frequency signal and The LO signal is mixed up by the first mixer and outputs 2300MHz / 2400MHz / … / 3900MHz and other intermodulation signals. These signals are filtered by three-stage FBAR frequency filtering to extract the 3200MHz frequency signal and suppress other signals.

[0076] e) The extracted 3200MHz frequency signal enters the RF port of the second mixer and outputs the power divider After the coherent local oscillator signal is down-mixed, an 800MHz point frequency signal and other intermodulation products are generated.

[0077] f) The output 800MHz frequency signal and other intermodulation components are filtered by LFCN-1700, which suppresses the intermodulation components and extracts the 800MHz frequency signal.

[0078] g) The DA output voltage is gradually adjusted and amplified by the operational amplifier circuit to the output. The RFOUT (pin 15) of the tuned voltage-controlled oscillator outputs 4.1GHz / 4.2GHz / … / 4.9GHz signals in sequence, and finally the 800MHz / 900MHz / … / 1700MHz frequency signals are extracted in sequence.

[0079] The above-described embodiments merely represent specific implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of protection of the present application. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the technical concept of the present application, and all such variations and improvements fall within the scope of protection of the present application.

[0080] This background section is provided to generally present the context of the invention, and the work of the presently named inventors, the work to the extent described in this background section, and aspects of the description in this section that did not constitute prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art to the present invention.

Claims

1. A broadband reconfigurable comb spectrum point frequency extraction system, characterized in that: include: Comb spectrum generator, which multiplies the input signal and outputs multi-harmonic signals; A first mixer, whose input port is connected to the output end of the comb spectrum generator, is used to up-mix the multi-harmonic signal with the coherent local oscillator signal to generate a mixed signal; a narrowband frequency filter connected to the output end of the first mixer and used for extracting the frequency signal from the mixed signal; The second mixer has an input port connected to the output end of the narrowband frequency filter, and is used to down-mix the frequency signal with the coherent local oscillator signal, shift the frequency signal spectrum back to the original frequency of the signal, and complete the extraction of the frequency signal; A voltage-controlled oscillator, the output end of which is connected to the local oscillator ports of the first mixer and the second mixer respectively through a power divider, for providing a coherent local oscillator signal with adjustable frequency and consistent phase; The control module is connected to the voltage-controlled oscillator and is used to calculate and configure the frequency value of the coherent local oscillator signal according to the frequency of the point frequency signal, so that the point frequency signal to be extracted falls within the passband range of the narrowband point frequency filter after up-mixing, and is restored to the original frequency after down-mixing.

2. A broadband reconfigurable comb spectrum point frequency extraction system according to claim 1, characterized in that: The narrowband frequency filter has a fixed passband center frequency, and the passband bandwidth of the narrowband frequency filter is less than 1 / 4 of the input signal frequency.

3. A broadband reconfigurable comb spectrum point frequency extraction system according to claim 2, characterized in that: Around the center frequency of the narrowband point frequency filter passband It has a suppression capability of more than 60dB.

4. A broadband reconfigurable comb spectrum point frequency extraction system according to claim 3, characterized in that: The frequency error or fluctuation range of the coherent local oscillator signal output by the coherent local oscillator signal source does not exceed that of the narrow-band point frequency filter.

5. The broadband reconfigurable comb spectrum point frequency extraction system according to claim 1, characterized in that: The control module includes: a DA and an operational amplifier circuit.

6. The broadband reconfigurable comb spectrum point frequency extraction system according to claim 1, characterized in that: Also includes: The first low-pass filter is arranged between the comb spectrum generator and the first mixer, and is used to filter out the high-order harmonic signals that do not need to be extracted from the multi-harmonic signals.

7. A broadband reconfigurable comb spectrum point frequency extraction system according to claim 6, characterized in that: Also includes: The second low-pass filter has an input port connected to the output end of the second mixer, and is used to filter out other intermodulation components after down-mixing and output the extracted point frequency signal.

8. A broadband reconfigurable comb spectrum point frequency extraction method, characterized in that: include: Step S1: Determine the voltage controlled oscillator output signal frequency; Step S2: Use a power divider to divide the output signal The equal-phase power is divided into two paths and transmitted to the first mixer and the second mixer respectively as the coherent local oscillator signals of the two mixers; Step S3: Using the first mixer and the coherent local oscillator signal Mixing the spectrum of the multi-harmonic signal to be extracted to obtain a mixed signal; Step S4: extracting a frequency signal from the mixed signal through a narrowband frequency filter; Step S5: Using the second mixer and the coherent local oscillator signal The frequency spectrum of the point frequency signal is moved and restored to the original frequency of the signal to complete the extraction of the point frequency signal.

9. A broadband reconfigurable comb spectrum point frequency extraction method according to claim 8, characterized in that: The step S1 comprises: calculate hour The frequency value controls the DA and operational amplifier circuit outputs corresponding The voltage-controlled voltage VT of the frequency value is tuned to output the corresponding frequency of the voltage-controlled oscillator. Signal.

10. The broadband reconfigurable comb spectrum point frequency extraction method according to claim 8, characterized in that: Also includes: Before up-mixing in step S3, a first low-pass filter is used to filter out higher harmonic signals that do not need to be extracted from the multi-harmonic signal; After down-mixing in step S5, other intermodulation components after down-mixing are filtered out using a second low-pass filter, and the extracted point frequency signal is output.

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