Numerically-controlled electrically-controlled wave trap and number selection control method

Abstract

The invention provides a numerical control electrically tunable wave trap and a number selection control method, and belongs to the technical field of wave trap modulation. Comprising a numerical control circuit used for generating driving signals; the at least one trap circuit is used for receiving the driving signal generated by the numerical control circuit and carrying out trap processing on an input radio frequency signal; the vector network analyzer is electrically connected with the output end of the at least one trap circuit and is used for carrying out frequency sweeping processing on the output radio frequency signal subjected to trap processing by the at least one trap circuit and outputting trap frequency information; the PC is in communication connection with the vector network analyzer and is used for setting the sweep frequency range of the vector network analyzer and obtaining the relationship between the driving signal and the notch frequency information; and the upper computer is in communication connection with the PC, obtains a driving signal matched with the notch frequency band according to the relation between the driving signal obtained by the PC and the notch frequency, and feeds back the driving signal to the numerical control circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of wave trap adjustment, and in particular to a digitally controlled electrically adjustable wave trap and a number selection control method. Background Art

[0002] The notch filter is a band-stop filter that blocks the signal of a specified frequency. By modulating the parameters, the specified signal can be removed or attenuated in a specified frequency band. Corresponding to the resonance phenomenon that enhances a certain frequency, the notch filter will attenuate the signal in the specified frequency band, while the signal in the non-specified frequency band will be maintained. The notch filter has been applied in the fields of communication, signal processing, etc.

[0003] Although the common single-pole digitally controlled electrically adjustable notch filter has low passband insertion loss, its notch depth is also low, and its 3dB bandwidth is narrow, and its applicability is low. When dealing with multiple spurious signals in multiple frequency bands, it is often necessary to cascade multiple notch filters to trap these signals, and there may be mutual interference between multiple notch filters, which is difficult to achieve using existing notch filters in the selection method.

[0004] Based on the above problems, a digitally controlled electrically adjustable notch filter and a selection control method are proposed, which has a good notch depth and can better trap multiple stray signals, which is very necessary. Summary of the invention

[0005] In view of this, the present invention proposes a digitally controlled electrically adjustable notch filter and a selection control method which has high integration, good scalability, and can notch multiple frequency bands or increase the notch depth of the same notch frequency band.

[0006] In one aspect, the present invention provides a digitally controlled electrically adjustable trap filter, comprising:

[0007] A digital control circuit for generating a driving signal;

[0008] at least one notch circuit, receiving the driving signal generated by the digital control circuit and performing notch processing on the input radio frequency signal;

[0009] A vector network analyzer is electrically connected to the output end of the at least one trap circuit, and is used to perform frequency sweep processing on the output radio frequency signal after trap processing of the at least one trap circuit, and output trap frequency information;

[0010] A PC is connected to the vector network analyzer for setting the frequency sweep range of the vector network analyzer and obtaining the relationship between the driving signal and the notch frequency information;

[0011] The host computer is connected to the PC for communication, and obtains a driving signal adapted to the notch frequency band according to the relationship between the driving signal obtained by the PC and the notch frequency, and feeds it back to the numerical control circuit.

[0012] On the basis of the above technical solution, preferably, the digital control circuit includes a single-chip microcomputer and several operational amplifier units, the single-chip microcomputer is communicatively connected to the host computer, and the single-chip microcomputer has several DAC output terminals; the several DAC output terminals are electrically connected to the input terminals of several operational amplifier units in a one-to-one correspondence, and the output terminals of the several operational amplifier units are electrically connected to the bias terminal of at least one trap circuit.

[0013] Preferably, the operational amplifier unit includes an operational amplifier, a tenth inductor L10, a third capacitor C3, a fourth capacitor C4, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9; the DAC output end is electrically connected to the in-phase input end of the operational amplifier, the power supply VBB is electrically connected to one end of the third capacitor C3 and one end of the tenth inductor L10 respectively, the other end of the tenth capacitor L10 is electrically connected to one end of the fourth capacitor C4 and the power supply end of the operational amplifier respectively, and the other end of the third capacitor C3 and the other end of the fourth capacitor C4 are grounded; the output end of the operational amplifier is electrically connected to one end of the seventh resistor R7 and one end of the eighth resistor R8 respectively, the other end of the eighth resistor is electrically connected to one end of the ninth resistor R9 and the inverting input end of the operational amplifier respectively, and the other end of the ninth resistor R9 is grounded; the other end of the seventh resistor R7 serves as the output end of the operational amplifier unit.

[0014] Further preferably, the at least one trap circuit includes a first inductor L1, a first resistor R1, a fourth inductor L4, a main trap unit and a branch trap unit; the main trap unit includes a first varactor diode VT1, a first capacitor C1, a second inductor L2, a second resistor R2, a first diode D1 and a second diode D2, one end of the first inductor L1 is electrically connected to the input RF signal, the other end of the first inductor L1 is respectively electrically connected to one end of the second inductor L2 and one end of the first capacitor C1, the other end of the first capacitor C1 is respectively electrically connected to the cathode of the first diode D1, the cathode of the second diode D2 and one end of the second resistor R2, the other end of the second resistor R2 is electrically connected to the anode of the first varactor diode VT1, the cathode of the first varactor diode VT1 is grounded, the other end of the second inductor L2 is respectively connected to the anode of the first diode D1, the anode of the second diode D2, one end of the first resistor R1, the branch trap unit and the fourth inductor L4 One end is electrically connected, the other end of the first resistor R1 is grounded, and the other end of the fourth inductor L4 is used as the output end of the trap circuit to output the radio frequency signal; the branch trap unit includes a second varactor diode VT2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a third resistor R3 and a third inductor L3, an anode of the third diode D3 and an anode of the fifth diode D5 are respectively electrically connected to the non-grounded end of the first resistor R1, a cathode of the third diode D3 is respectively electrically connected to the cathode of the fifth diode D5, the cathode of the fourth diode D4, the cathode of the sixth diode D6 and one end of the third resistor R3, and the other end of the third resistor R3 is electrically connected to the anode of the second varactor diode VT2; an anode of the fourth diode, an anode of the sixth diode D6 and a cathode of the second varactor diode VT2 are grounded; bias ends of the first varactor diode VT1 and the second varactor diode VT2 are respectively electrically connected to the output ends of different operational amplifier units.

[0015] More preferably, in the at least one trap circuit, the trap frequencies of the main trap unit and the branch trap unit are the same or different.

[0016] On the other hand, the present invention provides a digitally controlled electric notch filter and a selection control method, comprising the following steps:

[0017] S1: Configure the above-mentioned digitally controlled electric notch filter;

[0018] S2: starting the digital control circuit, so that the digital control circuit outputs different DAC signals to drive at least one trap circuit respectively;

[0019] S3: The digital control circuit generates a first driving signal DAC1, which is amplified by the operational amplifier unit, and drives the main notch unit of at least one notch circuit to perform independent notch processing on the notch frequency band of the input RF signal. The digital control circuit generates a second driving signal DAC2, which is amplified by the operational amplifier unit, and drives the notch frequency point of the branch notch unit of at least one notch circuit to move to the outside of the frequency band of the input RF signal.

[0020] S4: Start the vector network analyzer, respectively obtain the frequency of the main notch unit of at least one notch circuit during frequency sweep and the magnitude of the first drive signal DAC1 and save them to form a frequency point F1-DAC1 signal pair; send the frequency point F1-DAC1 signal pair to the PC;

[0021] S5: The DAC2 signal generated by the digital control circuit causes the branch trap unit of at least one trap circuit to perform trap processing on the trap frequency band of the input radio frequency signal, and at the same time causes DAC1 to drive the trap frequency point of the main trap unit of at least one trap circuit to move to the outside of the frequency band of the input radio frequency signal; using a vector network analyzer, respectively obtaining the frequency of the branch trap unit of at least one trap circuit during frequency sweeping and the size of the second drive signal DAC2 and saving them, forming a frequency point F2-DAC2 signal pair, and sending the frequency point F2-DAC2 signal pair to the PC;

[0022] S6: After the PC obtains the frequency-DAC1 signal pair and the frequency-DAC2 signal pair, it performs a segmented number selection operation to obtain the frequency and DAC1, DAC2 signals that meet the notch depth requirements when the main notch unit and the branch notch unit of at least one notch circuit perform notch processing simultaneously.

[0023] Preferably, the specific content of step S6 is:

[0024] S60: Perform function fitting on the frequency point F1-DAC1 signal pair and the frequency point F2-DAC2 signal pair respectively, to obtain a function F1 (DAC1) between the notch frequency point and DAC1 when the main notch unit of at least one notch circuit is independently notched; and a function F2 (DAC2) between the notch frequency point and DAC2 when the branch notch unit of at least one notch circuit is independently notched;

[0025] S61: segment the set notch frequency band S of the digital control electric notch filter to form a number of continuous sub-notch frequency bands S1, S2, ...S n-1 ;

[0026] S62: For each sub-notch frequency band, respectively obtain the DAC1 signal corresponding to the frequency point with the deepest notch depth between the starting position and the ending position of the sub-notch frequency band and its neighborhood of the function F1 (DAC1), which is recorded as DAC11, DAC12, ..., DAC1n Similarly, for each sub-notch frequency band, the DAC2 signal corresponding to the frequency point with the deepest notch depth in the neighborhood of the starting position and the ending position of the sub-notch frequency band of the function F2 (DAC2) is obtained, which is recorded as DAC21, DAC22, ..., DAC2 n ;

[0027] S63: In each sub-notch frequency band, at least one main notch unit and branch notch unit of a notch circuit are enabled simultaneously to perform joint notch processing, and according to the center frequency value of the current joint notch processing, a center frequency value that is closest to the starting position and the ending position of the sub-notch frequency band and has the deepest notch depth is found, and the DAC1 and DAC2 signals corresponding to the center frequency of each sub-notch frequency band under the joint notch processing are respectively recorded as DAC1 S = {DAC1 1’ DAC1 2’ , DAC1 n’} and DAC2 S = {DAC2 1’ DAC2 2’ , DAC2 n’}; then:

[0028] DAC1 S＝ =DAC1-△DAC1={DAC11-△DAC11, DAC12-△DAC12,…, DAC1 n -

[0029] △DAC1 n};

[0030] DAC2 S =DAC2+△DAC2={DAC21+△DAC21, DAC22+△DAC22,…, DAC2 n +

[0031] △DAC2 n}; △DAC1 and △DAC2 correspond to the deviation values ​​of the center frequency points of the joint notch processing of each sub-notch frequency band and the intermediate frequency points when each sub-notch frequency band is acted upon by the main notch unit or the branch notch unit of at least one notch circuit alone;

[0032] S64: constructing a relationship between a center frequency F obtained by simultaneous notching processing of a main notch unit and a branch notch unit of at least one notch circuit, and a second frequency point F1 (DAC1) when the main notch unit of at least one notch circuit works independently and a second frequency point F2 (DAC2) when the branch notch unit works independently;

[0033] F=W1×F1(DAC1-△DAC1)+W2×F2(DAC2+△DAC2)=W1×F1(DAC1 S )

[0034] +W2×F2(DAC2 S ), W1 and W2 are weight coefficients, and the value range of W1 and W2 is [0,1].

[0035] Further preferably, if the starting frequency and the ending frequency of the notch frequency band S are both integer multiples of 10 and 100 and can be equally divided, the frequency span range of each sub-notch frequency band is made equivalent; if the starting frequency or the ending frequency of the notch frequency band S is not an integer multiple of 10 and 100, or the starting frequency or the ending frequency is an integer multiple of 10 and 100 but cannot be equally divided, the frequency span ranges of the sub-notch frequency bands at non-head or end positions are set to be equivalent, and the remaining part is used as the head sub-notch frequency band and the end sub-notch frequency band.

[0036] Further preferably, the number of frequency-DAC1 signal pairs and frequency-DAC2 signal pairs is no less than 4096.

[0037] Further preferably, when the number of trap circuits exceeds one, the trap frequency bands S of different trap circuits are the same or different.

[0038] The digitally controlled electrically adjustable trap filter and the number selection control method provided by the present invention have the following beneficial effects compared with the prior art:

[0039] (1) The present invention provides a notch circuit of a digitally controlled electrically adjustable notch filter, wherein the main notch unit and the branch notch unit of the circuit respectively achieve resonance to achieve notch of two different specific frequency signals. The main notch unit and the branch notch unit of the same notch circuit can also resonate at the same frequency to achieve adjustment of notch depth at the same frequency.

[0040] (2) The present invention also provides a number selection control method, that is, a method for screening out a suitable resonant frequency of a notch circuit. By biasing a varactor diode, the corresponding relationship between the input DAC signal and the output frequency is obtained, and the optimal notch depth when the main notch unit and the branch notch unit work simultaneously is obtained, thereby improving the depth and reliability of the notch filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 It is a structural schematic diagram of an implementation mode of a digitally controlled electrically adjustable notch filter and a number selection control method of the present invention;

[0043] Figure 2 for Figure 1 The structural diagram of the trap circuit;

[0044] Figure 3 It is a structural schematic diagram of another implementation mode of a digitally controlled electrically adjustable trap filter and a number selection control method of the present invention;

[0045] Figure 4 for Figure 3 The structural diagram of the trap circuit;

[0046] Figure 5 The present invention provides a circuit diagram of an operational amplifier unit of a digitally controlled electrically adjustable notch filter and a number selection control method. DETAILED DESCRIPTION

[0047] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Example 1: Figure 1 , Figure 2 and Figure 5 As shown, the present invention provides a digitally controlled electrically adjustable notch filter, comprising:

[0049] A digital control circuit for generating a driving signal;

[0050] At least one trap circuit receives the driving signal generated by the digital control circuit and performs trap processing on the input radio frequency signal; in this embodiment, only one trap circuit is used. Figure 2 shown.

[0051] A vector network analyzer is electrically connected to the output end of the at least one trap circuit, and is used to perform frequency sweep processing on the output radio frequency signal after trap processing of the at least one trap circuit, and output trap frequency information;

[0052] A PC is connected to the vector network analyzer for setting the frequency sweep range of the vector network analyzer and obtaining the relationship between the driving signal and the notch frequency information;

[0053] The host computer is connected to the PC for communication, and obtains a driving signal adapted to the notch frequency band according to the relationship between the driving signal obtained by the PC and the notch frequency, and feeds it back to the numerical control circuit.

[0054] like Figure 1 As shown in the block diagram, the digital control circuit includes a single-chip microcomputer and a plurality of operational amplifier units. The single-chip microcomputer is connected to the host computer for communication. The single-chip microcomputer has a plurality of DAC output terminals. The plurality of DAC output terminals are electrically connected to the input terminals of the plurality of operational amplifier units in a one-to-one correspondence. The output terminals of the plurality of operational amplifier units are electrically connected to the bias terminal of at least one trap circuit. The single-chip microcomputer outputs a DAC analog signal to drive the trap circuit to perform trap processing.

[0055] like Figure 5 As shown, the operational amplifier unit includes an operational amplifier, a tenth inductor L10, a third capacitor C3, a fourth capacitor C4, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9; the DAC output end is electrically connected to the in-phase input end of the operational amplifier, the power supply VBB is electrically connected to one end of the third capacitor C3 and one end of the tenth inductor L10 respectively, the other end of the tenth capacitor L10 is electrically connected to one end of the fourth capacitor C4 and the power supply end of the operational amplifier respectively, and the other end of the third capacitor C3 and the other end of the fourth capacitor C4 are grounded; the output end of the operational amplifier is electrically connected to one end of the seventh resistor R7 and one end of the eighth resistor R8 respectively, the other end of the eighth resistor is electrically connected to one end of the ninth resistor R9 and the inverting input end of the operational amplifier respectively, and the other end of the ninth resistor R9 is grounded; the other end of the seventh resistor R7 serves as the output end of the operational amplifier unit. The operational amplifier unit constitutes a in-phase proportional amplifier, and the amplification factor is determined by the ratio of the eighth resistor R8 to the ninth resistor R9.

[0056] like Figure 2As shown, the trap circuit includes a first inductor L1, a first resistor R1, a fourth inductor L4, a main trap unit and a branch trap unit; the main trap unit includes a first variable capacitance diode VT1, a first capacitor C1, a second inductor L2, a second resistor R2, a first diode D1 and a second diode D2, one end of the first inductor L1 is electrically connected to the input RF signal, the other end of the first inductor L1 is respectively electrically connected to one end of the second inductor L2 and one end of the first capacitor C1, the other end of the first capacitor C1 is respectively electrically connected to the cathode of the first diode D1, the cathode of the second diode D2 and one end of the second resistor R2, the other end of the second resistor R2 is electrically connected to the anode of the first variable capacitance diode VT1, the cathode of the first variable capacitance diode VT1 is grounded, the other end of the second inductor L2 is respectively electrically connected to the anode of the first diode D1, the anode of the second diode D2, one end of the first resistor R1, the branch trap unit and one end of the fourth inductor L4 The branch trap unit includes a second varactor diode VT2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a third resistor R3 and a third inductor L3, an anode of the third diode D3 and an anode of the fifth diode D5 are electrically connected to the non-grounded end of the first resistor R1, a cathode of the third diode D3 is electrically connected to the cathode of the fifth diode D5, the cathode of the fourth diode D4, the cathode of the sixth diode D6 and one end of the third resistor R3, and the other end of the third resistor R3 is electrically connected to the anode of the second varactor diode VT2; an anode of the fourth diode, an anode of the sixth diode D6 and a cathode of the second varactor diode VT2 are grounded; bias ends of the first varactor diode VT1 and the second varactor diode VT2 are electrically connected to the output ends of different operational amplifier units, respectively. The single chip microcomputer modulates the first variable capacitance diode VT1 and / or the second variable capacitance diode VT2 through the output signal of the operational amplifier unit, so that the main path trap unit and the branch path trap unit resonate respectively.

[0057] Figure 2 The dotted box on the upper left includes the first inductor L1, the first resistor R1, the fourth inductor L4, and the main path trap unit, which is an independent trap input and output structure. The devices at both ends of the second inductor L2, the first capacitor C1, the first diode D1, the second diode D2, the second resistor R2 and the first variable capacitance diode VT1 together constitute an equivalent capacitor C10, that is, the equivalent capacitor C10 and the second inductor L2 constitute a resonant trap circuit in which the equivalent capacitor C10 is connected in parallel with the first inductor L1; the first inductor L1 and the second inductor L2 are both matching inductors of the equivalent capacitor C10, which are used to adjust the input impedance. Figure 2The third diode D3, the fourth diode D4, the fifth diode D5, the sixth diode D6, the third resistor R3 and the second varactor VT2 in the dotted box on the upper right constitute an equivalent capacitor C20, that is, the first resistor R1 is connected to the side away from the ground terminal and is connected to an equivalent capacitor C20 and a resonant trap circuit in series with the third inductor L3. In the figure, the first resistor R1 is connected to the reference ground of the first varactor VT1, and at the same time prevents the signal from leaking directly to the ground. The larger its resistance value, the smaller the circuit insertion loss, but at the same time it will affect the charging and discharging time of the first varactor VT1, resulting in a longer tuning time, so a suitable value needs to be selected. The second resistor R2 and the third resistor R3 are connected to the varactor diode respectively, preventing the signal from leaking from the bias circuit, and also affecting the tuning time.

[0058] In the trap circuit of this embodiment, the trap frequencies of the main trap unit and the branch trap unit are the same or different. If the trap frequencies of the main trap unit and the branch trap unit are the same, a deeper trap depth is achieved; if the trap frequencies of the main trap unit and the branch trap unit are different, the ability to trap two different frequency points is achieved.

[0059] Example 2: Figure 3 and Figure 4 As shown, the difference between this embodiment and embodiment 1 is that: in this embodiment, two trap circuits are used. Figure 4 The first two dashed boxes correspond to the first trap circuit. Figure 4 The last two dotted boxes correspond to the second trap circuit, and the structures of the two trap circuits are exactly the same. From left to right, the structures and equivalent circuits of the first and third dotted boxes are exactly the same, and the structures and equivalent circuits of the second and fourth dotted boxes are exactly the same, with only the numbers of the circuit components being different. They also constitute a parallel resonant trap circuit and a series resonant trap circuit.

[0060] A sixth inductor L6 for impedance matching is also provided between the output end of the first trap circuit and the input end of the second trap circuit. When the number of trap circuits exceeds one, the trap frequency bands S of different trap circuits are the same or different: in two different trap circuits, the trap frequencies of the main trap units can be the same or different; the trap frequencies of two different branch trap units can be the same or different. That is, there is at least one trap frequency and at most four trap frequencies.

[0061] Embodiment 3: The present invention provides a digitally controlled electrically adjustable trap filter and a selection control method, comprising the following steps:

[0062] S1: Configure the digitally controlled electrically adjustable trap filter described in Example 1 or Example 2.

[0063] S2: Start the digital control circuit so that the digital control circuit outputs different DAC signals to drive at least one trap circuit respectively.

[0064] S3: The digital control circuit generates a first drive signal DAC1 which is amplified by the operational amplifier unit and drives the main notch unit of at least one notch circuit to perform independent notch processing on the notch frequency band of the input RF signal. The digital control circuit generates a second drive signal DAC2 which is amplified by the operational amplifier unit and drives the branch notch unit of at least one notch circuit to move the notch frequency point to outside the frequency band of the input RF signal.

[0065] S4: Start the vector network analyzer, obtain the frequency of the main notch unit of at least one notch circuit during frequency sweep and the magnitude of the first drive signal DAC1 and save them to form a frequency point F1-DAC1 signal pair; send the frequency point F1-DAC1 signal pair to the PC.

[0066] S5: The DAC2 signal generated by the digital control circuit causes the branch trap unit of at least one trap circuit to perform trap processing on the trap frequency band of the input RF signal, and at the same time causes DAC1 to drive the trap frequency point of the main trap unit of at least one trap circuit to move outside the frequency band of the input RF signal; using a vector network analyzer, respectively obtain the frequency of the branch trap unit of at least one trap circuit during frequency scanning and the size of the second drive signal DAC2 and save them to form a frequency point F2-DAC2 signal pair, and send the frequency point F2-DAC2 signal pair to the PC; for example, the single-chip microcomputer drives DAC1 and the operational amplifier unit to output a 0-22V bias signal to obtain the relationship between the trap frequency and the DAC1 value, and the relationship between the trap frequency and the DAC1 value.

[0067] S6: After the PC obtains the frequency-DAC1 signal pair and the frequency-DAC2 signal pair, it performs a segmented number selection operation to obtain the frequency and DAC1, DAC2 signals that meet the notch depth requirements when the main notch unit and the branch notch unit of at least one notch circuit perform notch processing simultaneously.

[0068] The specific content of step S6 is:

[0069] S60: Perform function fitting on the frequency point F1-DAC1 signal pair and the frequency point F2-DAC2 signal pair respectively, to obtain a function F1 (DAC1) between the notch frequency point and DAC1 when the main notch unit of at least one notch circuit is independently notched; and a function F2 (DAC2) between the notch frequency point and DAC2 when the branch notch unit of at least one notch circuit is independently notched;

[0070] S61: segment the set notch frequency band S of the digital control electric notch filter to form a number of continuous sub-notch frequency bands S1, S2, ...S n-1 ;

[0071] If the starting frequency and the ending frequency of the notch frequency band S are both integer multiples of 10 and 100 and can be equally divided, the frequency span range of each sub-notch frequency band is made equivalent; if the starting frequency or the ending frequency of the notch frequency band S is not an integer multiple of 10 and 100, or the starting frequency or the ending frequency is an integer multiple of 10 and 100 but cannot be equally divided, the frequency span range of each sub-notch frequency band at a non-head or end position is set to be equivalent, and the remaining part is used as the head sub-notch frequency band and the end sub-notch frequency band.

[0072] For example, the 225-678MHz notch filter frequency band cannot be divided into 100 equal parts, and can be divided into five segments: 225-300MHz, 300-400MHz, 400-500MHz, 500-600MHz, and 600-678MHz for selection. The middle sub-notch frequency band has a bandwidth of 100MHz; and the sub-notch frequency bands at both ends of the first segment are 75Mhz and 78MHz respectively.

[0073] S62: For each sub-notch frequency band, respectively obtain the DAC1 signal corresponding to the frequency point with the deepest notch depth between the starting position and the ending position of the sub-notch frequency band and its neighborhood of the function F1 (DAC1), which is recorded as DAC11, DAC12, ..., DAC1 n Similarly, for each sub-notch frequency band, the DAC2 signal corresponding to the frequency point with the deepest notch depth in the neighborhood of the starting position and the ending position of the sub-notch frequency band of the function F2 (DAC2) is obtained, which is recorded as DAC21, DAC22, ..., DAC2 n ;

[0074] As a preferred implementation manner, the number of frequency-DAC1 signal pairs and frequency-DAC2 signal pairs is no less than 4096.

[0075] S63: In each sub-notch frequency band, at least one main notch unit and branch notch unit of a notch circuit are enabled simultaneously to perform joint notch processing, and according to the center frequency value of the current joint notch processing, a center frequency value that is closest to the starting position and the ending position of the sub-notch frequency band and has the deepest notch depth is found, and the DAC1 and DAC2 signals corresponding to the center frequency of each sub-notch frequency band under the joint notch processing are respectively recorded as DAC1 S = {DAC1 1’ DAC1 2’ , DAC1 n’} and DAC2 S = {DAC2 1’ DAC2 2’ , DAC2 n’}; then:

[0076] DAC1 S =DAC1-△DAC1={DAC11-△DAC11, DAC12-△DAC12,…, DAC1 n -

[0077] △DAC1 n};

[0078] DAC2 S =DAC2+△DAC2={DAC21+△DAC21, DAC22+△DAC22,…, DAC2 n +

[0079] △DAC2 n}; △DAC1 and △DAC2 correspond to the deviation value of the center frequency point of the joint notch processing of each sub-notch frequency band and the intermediate frequency point when each sub-notch frequency band is acted upon by the main notch unit or the branch notch unit of at least one notch circuit alone.

[0080] S64: constructing a relationship between a center frequency F obtained by simultaneous notching processing of a main notch unit and a branch notch unit of at least one notch circuit, and a second frequency point F1 (DAC1) when the main notch unit of at least one notch circuit works independently and a second frequency point F2 (DAC2) when the branch notch unit works independently;

[0081] F=W1×F1(DAC1-△DAC1)+W2×F2(DAC2+△DAC2)=W1×F1(DAC1 S )

[0082] +W2×F2(DAC2 S ), W1 and W2 are weight coefficients, and the value range of W1 and W2 is [0,1].

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A digitally controlled electrically adjustable notch filter, characterized in that: include: A digital control circuit for generating a driving signal; at least one notch circuit, receiving the driving signal generated by the digital control circuit and performing notch processing on the input radio frequency signal; A vector network analyzer is electrically connected to the output end of the at least one trap circuit, and is used to perform frequency sweep processing on the output radio frequency signal after trap processing of the at least one trap circuit, and output trap frequency information; A PC is connected to the vector network analyzer for setting the frequency sweep range of the vector network analyzer and obtaining the relationship between the driving signal and the notch frequency information; The host computer is connected to the PC for communication, and obtains a driving signal adapted to the notch frequency band according to the relationship between the driving signal obtained by the PC and the notch frequency, and feeds it back to the numerical control circuit.

2. The digitally controlled electrically adjustable notch filter according to claim 1, characterized in that: The digital control circuit includes a single-chip microcomputer and a plurality of operational amplifier units. The single-chip microcomputer is communicatively connected to a host computer, and the single-chip microcomputer has a plurality of DAC output terminals. The plurality of DAC output terminals are electrically connected to the input terminals of the plurality of operational amplifier units in a one-to-one correspondence, and the output terminals of the plurality of operational amplifier units are electrically connected to the bias terminal of at least one trap circuit.

3. The digitally controlled electrically adjustable notch filter according to claim 2, characterized in that: The operational amplifier unit includes an operational amplifier, a tenth inductor L10, a third capacitor C3, a fourth capacitor C4, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9; the DAC output end is electrically connected to the in-phase input end of the operational amplifier, the power supply VBB is electrically connected to one end of the third capacitor C3 and one end of the tenth inductor L10 respectively, the other end of the tenth capacitor L10 is electrically connected to one end of the fourth capacitor C4 and the power supply end of the operational amplifier respectively, and the other end of the third capacitor C3 and the other end of the fourth capacitor C4 are grounded; the output end of the operational amplifier is electrically connected to one end of the seventh resistor R7 and one end of the eighth resistor R8 respectively, the other end of the eighth resistor is electrically connected to one end of the ninth resistor R9 and the inverting input end of the operational amplifier respectively, and the other end of the ninth resistor R9 is grounded; the other end of the seventh resistor R7 serves as the output end of the operational amplifier unit.

4. The digitally controlled electrically adjustable notch filter according to claim 3, characterized in that: The at least one trap circuit includes a first inductor L1, a first resistor R1, a fourth inductor L4, a main trap unit and a branch trap unit; the main trap unit includes a first variable capacitance diode VT1, a first capacitor C1, a second inductor L2, a second resistor R2, a first diode D1 and a second diode D2, one end of the first inductor L1 is electrically connected to the input RF signal, the other end of the first inductor L1 is electrically connected to one end of the second inductor L2 and one end of the first capacitor C1, and the other end of the first capacitor C1 is electrically connected to the first diode D1 and the second diode D2. 1, the cathode of the second diode D2 and one end of the second resistor R2 are electrically connected, the other end of the second resistor R2 is electrically connected to the anode of the first varactor diode VT1, the cathode of the first varactor diode VT1 is grounded, the other end of the second inductor L2 is electrically connected to the anode of the first diode D1, the anode of the second diode D2, one end of the first resistor R1, the branch trap unit and one end of the fourth inductor L4 respectively, the other end of the first resistor R1 is grounded, and the other end of the fourth inductor L4 serves as an output end of the trap circuit to output the RF signal; The branch trap unit includes a second varactor diode VT2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a third resistor R3 and a third inductor L3, the anode of the third diode D3 and the anode of the fifth diode D5 are respectively electrically connected to the non-grounded end of the first resistor R1, the cathode of the third diode D3 is respectively electrically connected to the cathode of the fifth diode D5, the cathode of the fourth diode D4, the cathode of the sixth diode D6 and one end of the third resistor R3, the other end of the third resistor R3 is electrically connected to the anode of the second varactor diode VT2; the anode of the fourth diode, the anode of the sixth diode D6 and the cathode of the second varactor diode VT2 are grounded; the bias ends of the first varactor diode VT1 and the second varactor diode VT2 are respectively electrically connected to the output ends of different operational amplifier units.

5. The digitally controlled electrically adjustable notch filter according to claim 4, characterized in that: In the at least one trap circuit, the trap frequencies of the main trap unit and the branch trap unit are the same or different.

6. A method for selecting a digital control of a digitally controlled electric notch filter, characterized in that: The steps include: S1: A digitally controlled electrically adjustable trap filter as described in any one of claims 4 to 5 is configured; S2: starting the digital control circuit, so that the digital control circuit outputs different DAC signals to drive at least one trap circuit respectively; S3: The digital control circuit generates a first driving signal DAC1, which is amplified by the operational amplifier unit, and drives the main notch unit of at least one notch circuit to perform independent notch processing on the notch frequency band of the input RF signal. The digital control circuit generates a second driving signal DAC2, which is amplified by the operational amplifier unit, and drives the notch frequency point of the branch notch unit of at least one notch circuit to move to the outside of the frequency band of the input RF signal. S4: Start the vector network analyzer, respectively obtain the frequency of the main notch unit of at least one notch circuit during frequency sweep and the magnitude of the first drive signal DAC1 and save them to form a frequency point F1-DAC1 signal pair; send the frequency point F1-DAC1 signal pair to the PC; S5: The DAC2 signal generated by the digital control circuit causes the branch notch unit of at least one notch circuit to perform notch processing on the notch frequency band of the input RF signal, and at the same time causes DAC1 to drive the notch frequency point of the main notch unit of at least one notch circuit to move to the outside of the frequency band of the input RF signal; Using a vector network analyzer, respectively obtaining the frequency of the branch trap unit of at least one trap circuit during frequency sweep and the magnitude of the second drive signal DAC2 and saving them, forming a frequency point F2-DAC2 signal pair, and sending the frequency point F2-DAC2 signal pair to a PC; S6: After the PC obtains the frequency-DAC1 signal pair and the frequency-DAC2 signal pair, it performs a segmented number selection operation to obtain the frequency and DAC1, DAC2 signals that meet the notch depth requirements when the main notch unit and the branch notch unit of at least one notch circuit perform notch processing simultaneously.

7. A method for controlling the selection of digitally controlled electric notch filters according to claim 6, characterized in that: The specific content of step S6 is: S60: Perform function fitting on the frequency point F1-DAC1 signal pair and the frequency point F2-DAC2 signal pair respectively, to obtain a function F1 (DAC1) between the notch frequency point and DAC1 when the main notch unit of at least one notch circuit is independently notched; and a function F2 (DAC2) between the notch frequency point and DAC2 when the branch notch unit of at least one notch circuit is independently notched; S61: segment the set notch frequency band S of the digital control electric notch filter to form a number of continuous sub-notch frequency bands S1, S2, ...S n-1 ; S62: For each sub-notch frequency band, respectively obtain the DAC1 signal corresponding to the frequency point with the deepest notch depth between the starting position and the ending position of the sub-notch frequency band and its neighborhood of the function F1 (DAC1), which is recorded as DAC11, DAC12, ..., DAC1 n Similarly, for each sub-notch frequency band, the DAC2 signal corresponding to the frequency point with the deepest notch depth in the neighborhood of the starting position and the ending position of the sub-notch frequency band of the function F2 (DAC2) is obtained, which is recorded as DAC21, DAC22, ..., DAC2 n ; S63: In each sub-notch frequency band, at least one main notch unit and branch notch unit of a notch circuit are enabled simultaneously to perform joint notch processing, and according to the center frequency value of the current joint notch processing, a center frequency value that is closest to the starting position and the ending position of the sub-notch frequency band and has the deepest notch depth is found, and the DAC1 and DAC2 signals corresponding to the center frequency of each sub-notch frequency band under the joint notch processing are respectively recorded as DAC1 S = {DAC1 1’ DAC1 2’ , DAC1 n’ } and DAC2 S = {DAC2 1’ DAC2 2’ , DAC2 n’ }; then: DAC1 S＝ =DAC1-△DAC1={DAC11-△DAC11,DAC12-△DAC12,…,DAC1 n - △DAC1 n }; DAC2 S =DAC2+△DAC2={DAC21+△DAC21,DAC22+△DAC22,…,DAC2 n + △DAC2 n }; △DAC1 and △DAC2 correspond to the deviation values ​​of the center frequency points of the joint notch processing of each sub-notch frequency band and the intermediate frequency points when each sub-notch frequency band is acted upon by the main notch unit or the branch notch unit of at least one notch circuit alone; S64: constructing a relationship between a center frequency F obtained by simultaneous notching processing of a main notch unit and a branch notch unit of at least one notch circuit, and a second frequency point F1 (DAC1) when the main notch unit of at least one notch circuit works independently and a second frequency point F2 (DAC2) when the branch notch unit works independently; F=W1×F1(DAC1-△DAC1)+W2×F2(DAC2+△DAC2)=W1×F1(DAC1 S )+W2×F2(DAC2 S ), W1 and W2 are weight coefficients, and the value range of W1 and W2 is [0,1].

8. A method for controlling the selection of digital control electric notch filters according to claim 7, characterized in that: The content of step S61 is that if the starting frequency and the ending frequency of the notch frequency band S are both integer multiples of 10 and 100 and can be equally divided, the frequency span range of each sub-notch frequency band is made equivalent; if the starting frequency or the ending frequency of the notch frequency band S is not an integer multiple of 10 and 100, or the starting frequency or the ending frequency is an integer multiple of 10 and 100 but cannot be equally divided, the frequency span range of each sub-notch frequency band at a non-head or end position is set to be equivalent, and the remaining part is used as the head end notch frequency band and the end sub-notch frequency band.

9. The method for selecting a digital control method for a digitally controlled electric notch filter according to claim 6, characterized in that: The number of frequency-DAC1 signal pairs and frequency-DAC2 signal pairs shall be no less than 4096.

10. The method for selecting a digital control method for a digitally controlled electric notch filter according to claim 6, characterized in that: When the number of the trap circuits exceeds one, the trap frequency bands S of different trap circuits are the same or different.

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