Polar zero cancellation circuit based on 8421 code resistance network

By designing an extreme zero phase destruction circuit based on the 8421 code resistor network, the motor drive chip and double-bit double-throw relay are used to achieve quantitative control of resistance equivalent resistance value, which solves the problems of long adjustment time, limited bandwidth and leakage current in the prior art, and achieves high-precision and high-speed signal compensation and system performance improvement.

CN222721471UActive Publication Date: 2025-04-04XIAN CNNC NUCLEAR INSTRUMENT CO LTD
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Patent Information

Application Number
CN202421475281.1
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-06-25
Publication Date
2025-04-04
Estimated Expiration
2034-06-25

AI Technical Summary

Technical Problem

The existing pole-zero phase cancellation circuits have problems such as long adjustment time, inaccurate adjustment values ​​and cumbersome operation when adjusting the signal pole zero point. The limited bandwidth of the digital potentiometer may cause signal distortion, and the analog switch may introduce leakage current to cause the output signal to deviate from the ideal value.

Method used

A polar-zero phase-destruction circuit based on the 8421 code resistor network was designed, and a motor drive chip was used to drive a double-knife double-throw relay to achieve quantitative control of the equivalent resistance value of the connection circuit between the resistor VTT1 and the resistor VTT2, and compensate the signal with high accuracy and fast speed, eliminating non-ideal poles and zero points, and reducing pulse accumulation.

Benefits of technology

High-precision and high-speed signal compensation is achieved, which eliminates the phenomenon of undershoot and long tailings, reduces pulse accumulation, and improves the stability, frequency response and performance of the system.

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Abstract

The utility model discloses a pole zero cancellation circuit based on a 8421 code resistor network, which comprises a fixed capacitor connected between an input signal and an output signal, two ends of the fixed capacitor are connected with a variable resistor in parallel, the connecting end of the fixed capacitor and the output signal is grounded through the fixed resistor, the variable resistor comprises a resistor VTT1 and a resistor VTT2 which are connected in series, and the VTT2 is connected with the fixed capacitor. A connecting end of the resistors VTT1 and VTT2 is provided with an access line, one end, far away from the connecting end of the resistors VTT1 and VTT2, of the access line is connected with an output signal, the resistors VTT1 and VTT2 are 8421 code resistor networks, symmetrical resistors in the two 8421 code resistor networks are connected through a double-pole double-throw relay, and the double-pole double-throw relay is driven by a motor driving chip. According to the utility model, a non-ideal pole and zero point are generated after a compensation signal with high precision and high speed is amplified by the detector, so that the undershoot phenomenon and the long trailing phenomenon are eliminated, the pulse accumulation is reduced, and the system performance is improved.
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Description

Technical Field

[0001] The utility model belongs to the technical field of pole-zero cancellation circuits, and in particular relates to a pole-zero cancellation circuit based on an 8421 code resistor network. Background Art

[0002] Since the nuclear pulse signal output by the nuclear detector has a long tail and excessive undershoot, the signal amplitude is too large, causing the subsequent amplifier circuit to work in the nonlinear region for a period of time. In order to avoid this situation and reduce pulse accumulation and pulse distortion, it is necessary to use a pole-zero cancellation circuit to adjust the pole-zero point of the signal. At present, the existing pole-zero cancellation circuit mainly uses an analog potentiometer, a digital potentiometer or an analog switch to adjust the resistance value of different gears to adjust the pole-zero point of the signal, thereby reducing or eliminating the undershoot. For manually adjusting the sliding rheostat, it has the disadvantages of long adjustment time, inaccurate adjustment value and cumbersome operation; for adjustment through a digital potentiometer, most of the current digital potentiometers have limited bandwidth. When a high-frequency nuclear pulse signal passes through, insufficient bandwidth may cause signal distortion, resulting in the loss of pulse signals; analog switches must consider the influence of leakage current in the internal MOS tube, which may introduce additional offset voltage or offset current, causing the amplitude of the output signal to deviate from the ideal value. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a pole-zero cancellation circuit based on an 8421 code resistor network in view of the deficiencies in the above-mentioned prior art. The design is novel and reasonable. A motor driver chip is used to drive a double-pole double-throw relay to achieve quantitative control of the equivalent resistance value in the circuit connected between resistors VTT1 and VTT2. The non-ideal poles and zeros generated by the high-precision and high-speed compensation signal after amplification by the detector preamplifier are eliminated, the undershoot phenomenon and the long tail phenomenon are eliminated, and pulse accumulation is reduced, so as to improve the stability, frequency response and performance of the system, and facilitate popularization and use.

[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is: a pole-zero cancellation circuit based on an 8421 code resistor network, including a fixed capacitor C connected between an input signal and an output signal, a variable resistor is connected in parallel at both ends of the fixed capacitor C, and the connection end of the fixed capacitor C and the output signal is grounded through a fixed resistor R, characterized in that: the variable resistor includes a resistor VTT1 and a resistor VTT2 connected in series, and the connection end of the resistor VTT1 and the resistor VTT2 is provided with an access line, and one end of the access line away from the connection end of the resistor VTT1 and the resistor VTT2 is connected to the output signal, the resistor VTT1 is a first 8421 code resistor network, the resistor VTT2 is a second 8421 code resistor network, the first 8421 code resistor network and the second 8421 code resistor network are symmetrical structures, and the symmetrical resistors in the first 8421 code resistor network and the second 8421 code resistor network are connected through a double-pole double-throw relay, and the double-pole double-throw relay is driven by a motor drive chip.

[0005] The pole-zero cancellation circuit based on the 8421 code resistor network is characterized in that: the first 8421 code resistor network includes the thousandth 8421 code resistor, the hundredth 8421 code resistor, the tenth 8421 code resistor and the first 8421 code resistor connected in series in sequence;

[0006] The second 8421-code resistor network includes a second thousandth 8421-code resistor, a second hundredth 8421-code resistor, a twentieth 8421-code resistor and a second 8421-code resistor connected in series in sequence;

[0007] The first thousandth 8421 code resistor and the second thousandth 8421 code resistor each include an 8KΩ resistor, a 4KΩ resistor, a 2KΩ resistor and a 1KΩ resistor connected in series in sequence;

[0008] The 100th 8421-code resistor and the 200th 8421-code resistor both include an 800Ω resistor, a 400Ω resistor, a 200Ω resistor, and a 100Ω resistor connected in series in sequence;

[0009] The first tenth 8421-code resistor and the second tenth 8421-code resistor each include an 80Ω resistor, a 40Ω resistor, a 20Ω resistor and a 10Ω resistor connected in series in sequence;

[0010] The first 8421-code resistor and the second 8421-code resistor both include an 8Ω resistor, a 4Ω resistor, a 2Ω resistor, and a 1Ω resistor connected in series in sequence.

[0011] The above-mentioned pole-zero cancellation circuit based on the 8421 code resistor network is characterized in that: the 1Ω resistor in the first 8421 code resistor and the 1Ω resistor in the second 8421 code resistor are connected in series, and the 1Ω resistor in the first 8421 code resistor and the 1Ω resistor in the second 8421 code resistor are connected through an access line.

[0012] The above-mentioned pole-zero cancellation circuit based on the 8421 code resistor network is characterized in that: the symmetrical resistors in the first 8421 code resistor network and the second 8421 code resistor network include a first resistor and a second resistor with the same resistance value, one end of the first resistor is connected to the third pin of the double-pole double-throw relay, the other end of the first resistor is connected to the fourth pin of the double-pole double-throw relay, one end of the second resistor is connected to the sixth pin of the double-pole double-throw relay, and the other end of the second resistor is connected to the seventh pin of the double-pole double-throw relay.

[0013] The above-mentioned pole-zero cancellation circuit based on the 8421 code resistor network is characterized in that: the symmetrical resistors in the first 8421 code resistor network and the second 8421 code resistor network include 16 pairs, the number of the double-pole double-throw relays is equal to the number of symmetrical resistor pairs in the first 8421 code resistor network and the second 8421 code resistor network and corresponds one to one; the number of the motor drive chips is equal to the number of the double-pole double-throw relays and corresponds one to one.

[0014] The above-mentioned pole-zero cancellation circuit based on the 8421 code resistor network is characterized in that it also includes a serial-to-parallel input circuit, which includes four serial-to-parallel chips connected in sequence, the control ends of the four serial-to-parallel chips are all connected to the single-chip microcomputer, and the data ends of the four serial-to-parallel chips are connected to the 16 motor drive chips.

[0015] The above-mentioned pole-zero cancellation circuit based on the 8421 code resistor network is characterized in that: the serial-to-parallel chip includes a 74LV595PW serial-to-parallel chip, and the motor drive chip includes an MX612E motor drive chip.

[0016] The beneficial effects of the utility model are that the design is novel and reasonable, and the motor driving chip is used to drive the double-pole double-throw relay to achieve quantitative control of the equivalent resistance value in the circuit connected between the resistor VTT1 and the resistor VTT2. The non-ideal poles and zeros generated by the high-precision and high-speed compensation signal after amplification by the detector preamplifier are eliminated, the undershoot phenomenon and the long tail phenomenon are eliminated, and the pulse accumulation is reduced, so as to improve the stability, frequency response and performance of the system, and it is easy to promote and use.

[0017] The technical solution of the utility model is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the equivalent circuit principle diagram of the pole-zero cancellation circuit of the utility model.

[0019] Figure 2 The utility model is a schematic diagram of a thousand-digit control circuit of an 8421-code resistor network.

[0020] Figure 3 The utility model is a schematic diagram of the hundreds-digit control circuit of the 8421 code resistor network.

[0021] Figure 4 The utility model is a ten-bit control circuit schematic diagram of the 8421 code resistor network.

[0022] Figure 5 The utility model is a schematic diagram of the unit digit control circuit of the 8421 code resistor network.

[0023] Figure 6 The schematic diagram of the serial-to-parallel input circuit of the utility model is shown in FIG. DETAILED DESCRIPTION

[0024] like Figures 1 to 6 As shown, the utility model is a pole-zero cancellation circuit based on an 8421 code resistor network, including a fixed capacitor C connected between an input signal and an output signal, a variable resistor is connected in parallel at both ends of the fixed capacitor C, a connection end of the fixed capacitor C and the output signal is grounded through a fixed resistor R, the variable resistor includes a resistor VTT1 and a resistor VTT2 connected in series, an access line is provided at the connection end of the resistor VTT1 and the resistor VTT2, an end of the access line away from the connection end of the resistor VTT1 and the resistor VTT2 is connected to the output signal, the resistor VTT1 is a first 8421 code resistor network, the resistor VTT2 is a second 8421 code resistor network, the first 8421 code resistor network and the second 8421 code resistor network are symmetrical structures, and the symmetrical resistors in the first 8421 code resistor network and the second 8421 code resistor network are connected through a double-pole double-throw relay, and the double-pole double-throw relay is driven by a motor drive chip.

[0025] like Figures 2 to 5 As shown, in this embodiment, the first 8421-code resistor network includes the thousandth 8421-code resistor, the hundredth 8421-code resistor, the tenth 8421-code resistor and the first 8421-code resistor connected in series in sequence;

[0026] The second 8421-code resistor network includes a second thousandth 8421-code resistor, a second hundredth 8421-code resistor, a twentieth 8421-code resistor and a second 8421-code resistor connected in series in sequence;

[0027] The first thousandth 8421 code resistor and the second thousandth 8421 code resistor each include an 8KΩ resistor, a 4KΩ resistor, a 2KΩ resistor and a 1KΩ resistor connected in series in sequence;

[0028] The 100th 8421-code resistor and the 200th 8421-code resistor both include an 800Ω resistor, a 400Ω resistor, a 200Ω resistor, and a 100Ω resistor connected in series in sequence;

[0029] The first tenth 8421-code resistor and the second tenth 8421-code resistor each include an 80Ω resistor, a 40Ω resistor, a 20Ω resistor and a 10Ω resistor connected in series in sequence;

[0030] The first 8421-code resistor and the second 8421-code resistor both include an 8Ω resistor, a 4Ω resistor, a 2Ω resistor, and a 1Ω resistor connected in series in sequence.

[0031] It should be noted that the total resistance in the series structure of the first 8421 code resistor network and the second 8421 code resistor network is added to 16665Ω, and the first 8421 code resistor network and the second 8421 code resistor network are symmetrical structures. When the relay is switched to connect to different moving contacts, in the symmetrical resistance structure, only one side of the resistor with the same resistance is connected to the series circuit, and the other side of the resistor with the same resistance has an equivalent resistance value of 0 due to the short circuit. Since only one side of the two sides can be connected to the circuit, VTmid and VTT2 are connected. At this time, the equivalent resistance of VTT1 and VTT2 connected to the circuit is equal to the resistance of the series connection between VTT1 and VTmid. That is, the equivalent resistance in the circuit between VTT1 and VTT2 can be quantitatively controlled by the single-chip microcomputer, thereby compensating the input signal and realizing the pole-zero cancellation function.

[0032] In this embodiment, the 1Ω resistor in the first 8421-bit code resistor and the 1Ω resistor in the second 8421-bit code resistor are connected in series, and the 1Ω resistor in the first 8421-bit code resistor and the 1Ω resistor in the second 8421-bit code resistor are connected through an access line.

[0033] In this embodiment, the symmetrical resistors in the first 8421 code resistor network and the second 8421 code resistor network include a first resistor and a second resistor with the same resistance value, one end of the first resistor is connected to the third pin of the double-pole double-throw relay, the other end of the first resistor is connected to the fourth pin of the double-pole double-throw relay, one end of the second resistor is connected to the sixth pin of the double-pole double-throw relay, and the other end of the second resistor is connected to the seventh pin of the double-pole double-throw relay.

[0034] In this embodiment, the symmetrical resistors in the first 8421 code resistor network and the second 8421 code resistor network include 16 pairs, the number of the double-pole double-throw relays is equal to the number of symmetrical resistor pairs in the first 8421 code resistor network and the second 8421 code resistor network and corresponds one to one; the number of the motor drive chips is equal to the number of the double-pole double-throw relays and corresponds one to one.

[0035] In this embodiment, a serial-to-parallel input circuit is also included, and the serial-to-parallel input circuit includes four serial-to-parallel chips connected in sequence, the control ends of the four serial-to-parallel chips are all connected to the single-chip microcomputer, and the data ends of the four serial-to-parallel chips are connected to the 16 motor drive chips.

[0036] In this embodiment, the serial-to-parallel chip includes a 74LV595PW serial-to-parallel chip, the motor driver chip includes an MX612E motor driver chip, and the single-chip microcomputer includes an STM32F411VET6 chip.

[0037] It should be noted that because there are a large number of controlled relays, if the single-chip microcomputer directly controls it, it will occupy too many single-chip microcomputer pin resources, so the serial-to-parallel chip output is used. The power consumption required for the relay to work is relatively high. If it is directly driven by a single-chip microcomputer, the driving capability may be insufficient. Therefore, the single-chip microcomputer is used to connect the serial-to-parallel input circuit, and then control the motor driver chip. Each motor driver chip drives a relay to ensure the normal operation of the relay, thereby driving the relay to adjust the resistance value of the 8421 code resistor in the pole-to-zero cancellation circuit.

[0038] like Figures 2 to 6 As shown, the 16 motor drive chips are chips U1, U3, U5, U7, U9, U12, U14, U17, U20, U23, U25, U27, U29, U31, U33 and U35; the 16 double-pole double-throw relays are U2, U4, U6, U8, U10, U13, U15, U18, U21, U24, U26, U28, U30, U32, U34 and U36; the four serial-to-parallel chips are chips U11, U16, U19 and U22.

[0039] The utility model adopts the form of a relay combined with a resistor network, which can pass higher frequency signals while having a higher bandwidth, so as to ensure that the nuclear pulse signal containing high frequency passes through the pole-zero cancellation circuit without distortion. At the same time, the mechanical mechanism adopted can effectively avoid the generation of leakage current, eliminate the influence brought by the leakage current, so that the amplitude of the nuclear pulse signal passing through the pole-zero cancellation circuit remains unchanged, and the nuclear pulse signal retains the original information for the accuracy of subsequent analysis; the motor drive chip and the relay are combined with the 8421 code resistor network to form a system circuit; compared with the method of manually adjusting the resistance value to achieve the purpose of pole-zero cancellation, the time consumed in manually adjusting the resistance value is greatly saved, and the error caused by manual adjustment is avoided.

[0040] The above is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Any simple modification, change and equivalent structural change made to the above embodiments according to the technical essence of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A pole-zero cancellation circuit based on an 8421 code resistor network, comprising a fixed capacitor C connected between an input signal and an output signal, a variable resistor connected in parallel at both ends of the fixed capacitor C, and a connection end between the fixed capacitor C and the output signal being grounded via a fixed resistor R, characterized in that: The variable resistor includes a resistor VTT1 and a resistor VTT2 connected in series, and an access line is provided at the connection end of the resistor VTT1 and the resistor VTT2. One end of the access line away from the connection end of the resistor VTT1 and the resistor VTT2 is connected to the output signal. The resistor VTT1 is a first 8421 code resistor network, and the resistor VTT2 is a second 8421 code resistor network. The first 8421 code resistor network and the second 8421 code resistor network are symmetrically structured. The symmetrical resistors in the first 8421 code resistor network and the second 8421 code resistor network are connected through a double-pole double-throw relay, and the double-pole double-throw relay is driven by a motor drive chip.

2. A pole-zero cancellation circuit based on an 8421 code resistor network according to claim 1, characterized in that: The first 8421-code resistor network includes a thousandth 8421-code resistor, a hundredth 8421-code resistor, a tenth 8421-code resistor and a first 8421-code resistor connected in series in sequence; The second 8421-code resistor network includes a second thousandth 8421-code resistor, a second hundredth 8421-code resistor, a twentieth 8421-code resistor and a second 8421-code resistor connected in series in sequence; The first thousandth 8421-code resistor and the second thousandth 8421-code resistor each include an 8KΩ resistor, a 4KΩ resistor, a 2KΩ resistor, and a 1KΩ resistor connected in series in sequence; The 100th 8421-code resistor and the 200th 8421-code resistor both include an 800Ω resistor, a 400Ω resistor, a 200Ω resistor, and a 100Ω resistor connected in series in sequence; The first tenth 8421-code resistor and the second tenth 8421-code resistor each include an 80Ω resistor, a 40Ω resistor, a 20Ω resistor and a 10Ω resistor connected in series in sequence; The first 8421-code resistor and the second 8421-code resistor both include an 8Ω resistor, a 4Ω resistor, a 2Ω resistor, and a 1Ω resistor connected in series in sequence.

3. A pole-zero cancellation circuit based on an 8421 code resistor network according to claim 2, characterized in that: The 1Ω resistor in the first 8421-code resistor and the 1Ω resistor in the second 8421-code resistor are connected in series, and the 1Ω resistor in the first 8421-code resistor and the 1Ω resistor in the second 8421-code resistor are connected through an access line.

4. A pole-zero cancellation circuit based on an 8421 code resistor network according to claim 1, characterized in that: The symmetrical resistors in the first 8421 code resistor network and the second 8421 code resistor network include a first resistor and a second resistor with the same resistance value, one end of the first resistor is connected to the third pin of the double-pole double-throw relay, the other end of the first resistor is connected to the fourth pin of the double-pole double-throw relay, one end of the second resistor is connected to the sixth pin of the double-pole double-throw relay, and the other end of the second resistor is connected to the seventh pin of the double-pole double-throw relay.

5. A pole-zero cancellation circuit based on an 8421 code resistor network according to claim 4, characterized in that: The symmetrical resistors in the first 8421 code resistor network and the second 8421 code resistor network include 16 pairs, the number of the double-pole double-throw relays is equal to the number of symmetrical resistor pairs in the first 8421 code resistor network and the second 8421 code resistor network and corresponds one to one; the number of the motor drive chips is equal to the number of the double-pole double-throw relays and corresponds one to one.

6. A pole-zero cancellation circuit based on an 8421 code resistor network according to claim 5, characterized in that: It also includes a serial-to-parallel input circuit, which includes four serial-to-parallel chips connected in sequence, the control ends of the four serial-to-parallel chips are all connected to the single-chip microcomputer, and the data ends of the four serial-to-parallel chips are connected to the 16 motor drive chips.

7. A pole-zero cancellation circuit based on an 8421 code resistor network according to claim 6, characterized in that: The serial-to-parallel chip includes a 74LV595PW serial-to-parallel chip, and the motor driver chip includes an MX612E motor driver chip.