CN112787606A - Signal reading circuit - Google Patents
Signal reading circuit Download PDFInfo
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- CN112787606A CN112787606A CN202011643480.5A CN202011643480A CN112787606A CN 112787606 A CN112787606 A CN 112787606A CN 202011643480 A CN202011643480 A CN 202011643480A CN 112787606 A CN112787606 A CN 112787606A
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- H03—ELECTRONIC CIRCUITRY
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Abstract
The invention discloses a signal reading circuit, which comprises an amplifying circuit and a filter circuit; the amplifying circuit comprises a single carrier integrating circuit and a double carrier integrating circuit, the single carrier integrating circuit and the double carrier integrating circuit are arranged in parallel, the input end of the single carrier integrating circuit or the double carrier integrating circuit is connected with an input signal, and the output end of the single carrier integrating circuit or the double carrier integrating circuit is connected with the input end of the filter circuit; the filter circuit comprises a low-pass filter, a high-pass filter, a band-stop filter and a band-pass filter; the low-pass filter, the high-pass filter, the band-stop filter and the band-pass filter are arranged in parallel; the input ends of the low-pass filter, the high-pass filter, the band-stop filter and the band-pass filter are respectively connected with the output end of the single carrier integrating circuit or the double carrier integrating circuit; according to the invention, through the series arrangement of the amplifying circuit and the filter circuit, a plurality of signal adjusting ranges are realized by adjusting different circuit structures; different circuit structures can be connected by rotating different switches to be closed; the flexibility is good, and the parameter variable range is big.
Description
Technical Field
The invention belongs to the technical field of detection circuits, and particularly relates to a signal reading circuit.
Background
The capacitance variation of the capacitive acceleration sensor is very small, a common amplifying circuit cannot achieve the amplifying effect, the circuit is easily influenced by device performance, parasitic capacitance or noise, and the single circuit has defects in function. The filtering aspect comprises digital filtering and switched capacitor filtering, wherein the digital filtering occupies excessive software resources, and the switched capacitor filtering circuit has the disadvantages of higher noise, limited cut-off frequency and higher price. The traditional signal reading circuit has the technical problems of small flexibility, low parameter variable range and small output amplitude change.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides a signal reading circuit to solve the technical problems of small flexibility, low parameter variable range and small output amplitude change of the traditional signal reading circuit.
In order to achieve the purpose, the invention adopts the technical scheme that:
the invention provides a signal reading circuit, which comprises an amplifying circuit and a filter circuit; the input end of the amplifying circuit is connected with the input signal, and the output end of the amplifying circuit is connected with the input end of the filter circuit;
the amplifying circuit comprises a single carrier integrating circuit and a double carrier integrating circuit, the single carrier integrating circuit and the double carrier integrating circuit are arranged in parallel, the input end of the single carrier integrating circuit or the double carrier integrating circuit is connected with an input signal, and the output end of the single carrier integrating circuit or the double carrier integrating circuit is connected with the input end of the filter circuit;
the filter circuit comprises a low-pass filter, a high-pass filter, a band-stop filter and a band-pass filter; the low-pass filter, the high-pass filter, the band-stop filter and the band-pass filter are arranged in parallel; the input ends of the low-pass filter, the high-pass filter, the band-stop filter and the band-pass filter are respectively connected with the output end of the single carrier integrating circuit or the double carrier integrating circuit.
Further, a switch S1 is arranged between the output end of the single carrier integrating circuit and the input end of the filter circuit, and a switch S2 is arranged between the output end of the double carrier integrating circuit and the input end of the filter circuit.
Further, the single-carrier integrating circuit comprises an integrated operational amplifier U6A, an integrated operational amplifier U7A, an integrated operational amplifier U8A, a capacitor C8, a capacitor C9, a capacitor C10, a capacitor C11, a resistor R16, a resistor R17, a resistor R18, a resistor R19 and a resistor R20; the integrated operational amplifier U6A and the integrated operational amplifier U7A are arranged in parallel, the positive input end of the integrated operational amplifier U6A is grounded, and the positive input end of the integrated operational amplifier U7A is grounded;
the reverse input end of the integrated operational amplifier U6A is connected with an input signal through a capacitor C8, and a resistor R16 and a capacitor C9 are connected between the reverse input end and the output end of the integrated operational amplifier U6A in parallel; the output end of the integrated operational amplifier U6A is connected with the positive input end of the integrated operational amplifier U8A through a resistor R19;
the reverse input end of the integrated operational amplifier is connected with an input signal through a capacitor C10, and a capacitor C11 and a resistor R17 are arranged between the reverse input end and the output end of the integrated operational amplifier U7A in parallel; the output end of the integrated operational amplifier U7A is connected between the inverted input end of the integrated operational amplifier U8A through a resistor R18; one end of the resistor R20 is connected with the inverted input end of the integrated operational amplifier U8A, and the other end is connected with the output end of the integrated operational amplifier U8A.
Further, the double-carrier integrating circuit comprises an integrated operational amplifier U5A, a capacitor C4, a capacitor C5 and a capacitor C6; one end of the capacitor C4 is connected with one end of an input signal, and the other end of the capacitor C4 is connected with the reverse input end of the integrated operational amplifier U5A; one end of the capacitor C5 is connected with the other end of the input signal, and the other end of the capacitor C5 is connected with the reverse input end of the integrated operational amplifier U5A; the positive input end of the integrated operational amplifier U5A is grounded, and the output end of the integrated operational amplifier U5A is connected with the input end of the amplifying circuit; one end of the capacitor C6 is connected with the inverted input end of the integrated operational amplifier U5A, and the other end is connected with the output end of the integrated operational amplifier U5A.
Furthermore, the capacitor C4 and the capacitor C5 both use ceramic chip capacitors, and the capacitor C6 uses an electrolytic capacitor.
Further, the low-pass filter comprises an integrated operational amplifier U2A, a resistor R4, a resistor R5 and a capacitor C3, one end of the resistor R5 is connected with the output end of the amplifying circuit, and the other end of the resistor R5 is connected with the reverse input end of the integrated operational amplifier U2A; the capacitor C3 and the resistor R4 are connected in parallel between the inverting input terminal and the output terminal of the integrated operational amplifier U2A.
Further, the high-pass filter comprises an integrated operational amplifier U1A, a capacitor C1, a resistor R3 and a resistor R1; the positive input end of the integrated operational amplifier U1A is grounded;
one end of the capacitor C1 is connected with the output end of the amplifying circuit, the other end of the capacitor C1 is connected with one end of the resistor R3, and the other end of the resistor R3 is connected with the reverse input end of the integrated operational amplifier U1A; one end of the resistor R1 is connected with the reverse input end of the integrated operational amplifier U1A, and the other end is connected with the output end of the integrated operational amplifier U1A.
Further, the band-pass filter comprises an integrated operational amplifier U1A, an integrated operational amplifier U3A, a capacitor C1, a capacitor C2, a resistor R1, a resistor R2, a resistor R3 and a resistor R6; one end of the capacitor C1 is connected with the output end of the amplifying circuit, the other end of the capacitor C1 is connected with one end of the resistor R3, and the other end of the resistor R3 is connected with the reverse input end of the integrated operational amplifier U1A;
the integrated operational amplifier U1A, the resistor R6 and the integrated operational amplifier U3A are sequentially connected in series, the output end of the integrated operational amplifier U1A is connected with one end of the resistor R6, and the other end of the resistor R6 is connected with the reverse input end of the integrated operational amplifier U3A; one end of the resistor R1 is connected with the reverse input end of the integrated operational amplifier U1A, and the other end of the resistor R1 is connected with the output end of the integrated operational amplifier U1A; the capacitor C2 and the resistor R2 are connected in parallel between the inverting input terminal and the output terminal of the integrated operational amplifier U3A.
Further, the band elimination filter comprises an integrated operational amplifier U1A, an integrated operational amplifier U4A, a resistor R1, a resistor R7, a resistor R8 and a capacitor C1; one end of the capacitor C1 is connected with the output end of the amplifying circuit, the other end of the capacitor C1 is connected with one end of the resistor R3, and the other end of the resistor R3 is connected with the reverse input end of the integrated operational amplifier U1A;
one end of the resistor R1 is connected with the reverse input end of the integrated operational amplifier U1A, and the other end of the resistor R1 is connected with the output end of the integrated operational amplifier U1A; one end of the resistor R7 is connected with the output end of the integrated operational amplifier U1A, and the other end of the resistor R7 is connected with the reverse input end of the integrated operational amplifier U4A; one end of the resistor R8 is connected with the inverted input end of the integrated operational amplifier U4A, and the other end is connected with the output end of the integrated operational amplifier U4A.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a signal reading circuit.A single carrier circuit and a double carrier circuit are connected in parallel in an amplifying circuit, and the type of the amplifying circuit can be flexibly rotated according to the type of an input signal; the amplifying circuit adopts differential capacitance detection, so that the amplifying circuit has stronger anti-interference capability, and the double-carrier circuit can effectively avoid noise interference; after entering the filter circuit, according to a Laplace transform method and by combining basic operations such as proportion, integration and summation, a transfer function can be set as a constructed operation circuit so as to realize low-pass, high-pass, band-pass and band-stop filter functions, if a feedback path is a low-pass filter circuit, the whole circuit realizes high-pass filtering; if the feedback path is a high-pass filter circuit, the whole circuit realizes low-pass filtering; if the high-pass filter circuit and the low-pass filter circuit are connected in series and the parameters are reasonably selected, the whole circuit realizes band-pass filtering, and if the output of the high-pass filter circuit and the output of the low-pass filter circuit are connected to the summation operation circuit, the whole circuit executes band-stop filtering; good flexibility, large parameter variable range and large output amplitude variation.
Furthermore, the switch S1 and the switch S2 are arranged to be used for adjusting whether the circuit is connected with a single carrier circuit or a double carrier circuit, the signal amplification effect of different circuits is different when the circuits are connected, and the advantages of the switches are adjusted and flexibly selected.
Furthermore, compared with a double carrier wave, the phase difference of two signals is required to be completely close, the single carrier wave structure is simple, and the reflection interference in the signal transmission process can be reduced. The carrier-to-noise ratio threshold of the single carrier circuit is lower than that of a double carrier circuit. The double-carrier circuit has a large signal regulation range, and the amplification signal range is obvious compared with a single carrier.
Furthermore, the capacitor C4 and the capacitor C5 ceramic chip have better high-frequency characteristics, and can better perform filtering and coupling by utilizing the charging and discharging characteristics; the capacitor C6 adopts electrolytic capacitor as filter circuit in DC, and has DC isolating function, and can eliminate low frequency interference without AC, and the electrolytic capacitor with large capacity can prevent the low frequency component in signal from being lost too much.
Further, the low-pass filter utilizes the principle that the capacitor C3 passes high frequency and blocks low frequency, and the inductor R5 passes low frequency and blocks high frequency; for the high frequency needing to be cut off, the passing of the high frequency is blocked by using a method of capacitance absorption and inductance blocking, and for the low frequency needing to be cut off, the high frequency passes through the high frequency by using the characteristics of capacitance high resistance and inductance low resistance; signals below the cut-off frequency can be passed while signals above the cut-off frequency are blocked.
Furthermore, a high-pass filter circuit is formed by a capacitor C1 and a resistor R3, and the capacitor is used for blocking direct current and alternating current, namely high-frequency current can pass through the capacitor, and the capacitor is short-circuited for the high-frequency current; due to the fact that the capacitor blocks direct current and alternating current, for low-frequency signals, the capacitor is disconnected, and the low-frequency signals cannot pass through; so that high frequency signals can pass but low frequency signals cannot.
Further, the band-pass filter of the aeoni functions to pass signals within a frequency band centered on the center frequency and having a frequency range width B, while attenuating signals of all other frequencies; in fact, the signal can pass through the whole frequency passband to the maximum extent, and only the stopband has attenuation and inhibition effects on the passing signal, so that a proper signal is transmitted to a rear circuit; the band-stop filter attenuates or reduces the frequency range signal, but allows the passage of signals having frequencies below a lower cutoff frequency and above an upper cutoff frequency, thereby passing appropriate signals to subsequent circuitry.
In summary, the amplifying circuit and the filter circuit are connected in series, and a plurality of signal adjusting ranges are realized by adjusting different circuit structures; different circuit structures can be connected by rotating different switches to be closed.
Drawings
FIG. 1 is an overall circuit diagram of a signal sensing circuit according to the present invention;
fig. 2 is a general structural diagram of an amplifying circuit in the signal readout circuit according to the present invention;
FIG. 3 is a single carrier dual path integration circuit diagram in the signal readout circuit according to the present invention;
FIG. 4 is a diagram of a dual carrier integrator circuit in the signal readout circuit according to the present invention;
fig. 5 is a general structural diagram of a filter circuit in the signal readout circuit according to the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects of the present invention more apparent, the following embodiments further describe the present invention in detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 1 to 5, the present invention provides a signal readout circuit, which includes an amplifying circuit and a filtering circuit, wherein an input terminal of the amplifying circuit is connected to an input signal, and an output terminal of the amplifying circuit is connected to an input terminal of the filtering circuit.
The amplifying circuit comprises a single carrier integrating circuit and a double carrier integrating circuit, the single carrier integrating circuit and the double carrier integrating circuit are arranged in parallel, the input end of the single carrier integrating circuit or the double carrier integrating circuit is connected with an input signal, and the output end of the single carrier integrating circuit or the double carrier integrating circuit is connected with the input end of the filter circuit.
The filter circuit comprises a low-pass filter, a high-pass filter, a band-stop filter and a band-pass filter; the low-pass filter, the high-pass filter, the band-stop filter and the band-pass filter are arranged in parallel; the input ends of the low-pass filter, the high-pass filter, the band-stop filter and the band-pass filter are respectively connected with the output end of the single carrier integrating circuit or the double carrier integrating circuit.
A switch S1 is arranged between the output end of the single carrier integrating circuit and the input end of the filter circuit, and a switch S2 is arranged between the output end of the double carrier integrating circuit and the input end of the filter circuit.
The single-carrier integrating circuit comprises an integrated operational amplifier U6A, an integrated operational amplifier U7A, an integrated operational amplifier U8A, a capacitor C8, a capacitor C9, a capacitor C10, a capacitor C11, a resistor R16, a resistor R17, a resistor R18, a resistor R19 and a resistor R20; the integrated operational amplifier U6A and the integrated operational amplifier U7A are arranged in parallel, the positive input end of the integrated operational amplifier U6A is grounded, and the positive input end of the integrated operational amplifier U7A is grounded;
the reverse input end of the integrated operational amplifier U6A is connected with an input signal through a capacitor C8, and a resistor R16 and a capacitor C9 are connected between the reverse input end and the output end of the integrated operational amplifier U6A in parallel; the output end of the integrated operational amplifier U6A is connected with the positive input end of the integrated operational amplifier U8A through a resistor R19;
the reverse input end of the integrated operational amplifier is connected with an input signal through a capacitor C10, and a capacitor C11 and a resistor R17 are arranged between the reverse input end and the output end of the integrated operational amplifier U7A in parallel; the output end of the integrated operational amplifier U7A is connected between the inverted input end of the integrated operational amplifier U8A through a resistor R18; one end of the resistor R20 is connected with the inverted input end of the integrated operational amplifier U8A, and the other end is connected with the output end of the integrated operational amplifier U8A.
The double-carrier integrating circuit comprises an integrated operational amplifier U5A, a capacitor C4, a capacitor C5 and a capacitor C6; one end of the capacitor C4 is connected with one end of an input signal, and the other end of the capacitor C4 is connected with the reverse input end of the integrated operational amplifier U5A; one end of the capacitor C5 is connected with the other end of the input signal, and the other end of the capacitor C5 is connected with the reverse input end of the integrated operational amplifier U5A; the positive input end of the integrated operational amplifier U5A is grounded, and the output end of the integrated operational amplifier U5A is connected with the input end of the amplifying circuit; one end of the capacitor C6 is connected with the inverted input end of the integrated operational amplifier U5A, and the other end is connected with the output end of the integrated operational amplifier U5A.
The capacitor C4 and the capacitor C5 both adopt ceramic chip capacitors, and the capacitor C6 adopts an electrolytic capacitor.
The low-pass filter comprises an integrated operational amplifier U2A, a resistor R4, a resistor R5 and a capacitor C2, one end of the resistor R5 is connected with the output end of the amplifying circuit, and the other end of the resistor R5 is connected with the reverse input end of the integrated operational amplifier U2A; the capacitor C3 and the resistor R4 are connected in parallel between the inverting input terminal and the output terminal of the integrated operational amplifier U2A.
The high-pass filter comprises an integrated operational amplifier U1A, a capacitor C1, a resistor R3 and a resistor R1; the positive input end of the integrated operational amplifier U1A is grounded;
one end of the capacitor C1 is connected with the output end of the amplifying circuit, the other end of the capacitor C1 is connected with one end of the resistor R3, and the other end of the resistor R3 is connected with the reverse input end of the integrated operational amplifier U1A; one end of the resistor R1 is connected with the reverse input end of the integrated operational amplifier U1A, and the other end is connected with the output end of the integrated operational amplifier U1A.
The band-pass filter comprises an integrated operational amplifier U1A, an integrated operational amplifier U3A, a capacitor C1, a capacitor C2, a resistor R1, a resistor R2, a resistor R3 and a resistor R6; one end of the capacitor C1 is connected with the output end of the amplifying circuit, the other end of the capacitor C1 is connected with one end of the resistor R3, and the other end of the resistor R3 is connected with the reverse input end of the integrated operational amplifier U1A;
the integrated operational amplifier U1A, the resistor R6 and the integrated operational amplifier U3A are sequentially connected in series, the output end of the integrated operational amplifier U1A is connected with one end of the resistor R6, and the other end of the resistor R6 is connected with the reverse input end of the integrated operational amplifier U3A; one end of the resistor R1 is connected with the reverse input end of the integrated operational amplifier U1A, and the other end of the resistor R1 is connected with the output end of the integrated operational amplifier U1A; the capacitor C2 and the resistor R2 are connected in parallel between the inverting input terminal and the output terminal of the integrated operational amplifier U3A.
The band elimination filter comprises an integrated operational amplifier U1A, an integrated operational amplifier U4A, a resistor R1, a resistor R7, a resistor R8 and a capacitor C1; one end of the capacitor C1 is connected with the output end of the amplifying circuit, the other end of the capacitor C1 is connected with one end of the resistor R3, and the other end of the resistor R3 is connected with the reverse input end of the integrated operational amplifier U1A;
one end of the resistor R1 is connected with the reverse input end of the integrated operational amplifier U1A, and the other end of the resistor R1 is connected with the output end of the integrated operational amplifier U1A; one end of the resistor R7 is connected with the output end of the integrated operational amplifier U1A, and the other end of the resistor R7 is connected with the reverse input end of the integrated operational amplifier U4A; one end of the resistor R8 is connected with the inverted input end of the integrated operational amplifier U4A, and the other end is connected with the output end of the integrated operational amplifier U4A.
Principle of operation
According to the signal reading circuit, signals are input from an input end, and are switched through switches S1 and S2 to be selected to Pass through a single carrier integrating circuit or a double carrier integrating circuit, and after being processed by four filter circuits, namely a Low-Pass filter, a High-Pass filter, a Band-Stop filter and a Band-Pass filter, the final signal waveform result is checked at output ports of a Low Pass, a High Pass, a Band Pass and a Band Stop; and judging the type of the signal input by the original input end according to the four results, or judging the signal again by using a non-switching switch.
Examples
The embodiment provides a signal reading circuit, which comprises a double-carrier integrating circuit, a single-carrier integrating circuit, a low-pass filter, a high-pass filter, a band-stop filter and a band-pass filter;
the single carrier integrating circuit is connected with the signal input end of the double carrier integrating circuit, the output ends of the single carrier integrating circuit and the double carrier integrating circuit are connected with the input ends of the low-pass filter, the high-pass filter, the band-stop filter and the band-pass filter, and all the filters are connected in parallel.
The double-carrier integrating circuit comprises an integrated operational amplifier U5A, a capacitor C4, a capacitor C5 and a capacitor C6, wherein the capacitor C4 and the capacitor C5 are respectively connected with two input ends of signals, the capacitor C6 is connected with the reverse input end and the output end of the integrated operational amplifier U5A, and the forward input end of the U5A is grounded.
The capacitor C4 and the capacitor C5 are ceramic chip capacitors, and the capacitor C6 is an electrolytic capacitor.
The single-carrier integrating circuit comprises an integrated operational amplifier U6A and an integrated operational amplifier U7A, the integrated operational amplifier U8A, a capacitor C8, a capacitor C9, a capacitor C10, a capacitor C11, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R16 and a capacitor C9 which are respectively connected with a reverse input end and an output end of the integrated operational amplifier U6A, a resistor R7 and a capacitor C11 which are respectively connected with a reverse input end and an output end of the integrated operational amplifier U7A, a forward input end of the integrated operational amplifier U8A is connected with the integrated operational amplifier U6A through the resistor R19, a forward input end of the integrated operational amplifier U8A is connected with the integrated operational amplifier U7A through the resistor R18, and an output end of the integrated operational amplifier U8A is finally used as an input end of the filter circuit.
The low-pass filter comprises an integrated operational amplifier U2A, a resistor R4, a resistor R5 and a capacitor C2, wherein the resistor R4 is connected with the reverse input end of the U2A, and the resistor R5 and the capacitor C2 are respectively connected with the reverse input end and the output end of the U2A.
The band-pass filter comprises an integrated operational amplifier U1A, an integrated operational amplifier U3A, a capacitor C1, a capacitor C2 resistor R1, a resistor R2, a resistor R3 and a resistor R6, the resistor R3 and the resistor R1 are respectively connected with the reverse input end of the integrated operational amplifier U1A, the other end of the resistor R1 is connected with the output end of the integrated operational amplifier U1A, one ends of two ends of the resistor R6 are connected with the output end of the integrated operational amplifier U1A, the other end of the resistor R3A is connected with the reverse input end of the integrated operational amplifier U3A, one ends of the resistor R2 and the capacitor C2 are connected with one end of the reverse input end of the U3A to.
The band-elimination filter comprises an integrated operational amplifier U1A, an integrated operational amplifier U4A, a resistor R1, a resistor R7, a resistor R8, a capacitor C1, a feedback resistor R1 and a resistor R8 which are respectively connected with the two ends of the integrated operational amplifier U1A and the two ends of the integrated operational amplifier U4A, and the resistor R7 is connected with the two integrated operational amplifiers in series to form the band-elimination filter.
The high-pass filter comprises an integrated operational amplifier U1A, a resistor R3, a resistor R1 and a capacitor C1, wherein the capacitor C1 is connected with the resistor R3 and the integrated operational amplifier U1A in series, and a feedback resistor R1 is connected with the reverse input end and the output end of the integrated operational amplifier U1A in parallel to form the high-pass filter.
The embodiment aims at the signal reading circuit, the signal reading range flexibility is high, and for an output signal, the required low-frequency, high-frequency or specified-frequency waveform can be given according to different required scenes, so that the manufacturing process is saved, and multiple functions are realized. The signal readout circuit can be applied to various sensors.
The amplifying circuit part of the embodiment is formed by connecting a single carrier integrating circuit and a double carrier integrating circuit in parallel, so that the flexibility of parameters is improved; the single carrier circuit passes through a switch S1 and the double carrier circuit passes through a switch S2 and enters a filtering and amplifying circuit.
According to the type size of the input signal, a single carrier circuit or a double carrier circuit can be flexibly selected, and the amplifying circuit can have strong anti-interference capability by adopting differential capacitance detection, so that noise interference can be effectively avoided.
After entering the filter circuit, according to a Laplace transform method and by combining basic operations such as proportion, integration and summation, a transfer function can be set as a constructed operation circuit so as to realize low-pass, high-pass, band-pass and band-stop filter functions, if a feedback path is a low-pass filter circuit, the whole circuit realizes high-pass filtering; if the feedback path is a high-pass filter circuit, the whole circuit realizes low-pass filtering; if the high-pass filter circuit and the low-pass filter circuit are connected in series and the parameters are reasonably selected, the whole circuit realizes band-pass filtering, and if the output of the high-pass filter circuit and the output of the low-pass filter circuit are connected to the summation operation circuit, the whole circuit executes band-stop filtering.
The operational amplifier is mainly composed of two stages of amplifiers. The first stage is a differential amplifier, mainly with increased input resistance and common mode rejection ratio. The second stage amplifier is a source follower, which mainly improves the driving capability.
Connecting the operational amplifier, the resistor and the capacitor together to form a complete state variable filter circuit; the circuit is designed with four independent channels: the circuit has the advantages that high-pass, low-pass, band-pass and band-stop filtering are realized, the number of devices is limited, due to the independence of each filter path, the state variable filter can realize parallel output of a plurality of filtering, the filter characteristic of each path can be independently adjusted according to actual requirements, the circuit is simple in structure and high in flexibility, and all simulation graphs are simulated in music.
The integrated operational amplifier of the embodiment adopts an LM324 series, the LM324 is a conventional operational amplifier, the application range is wide, the four operational amplifiers with true differential inputs have true differential inputs, the four operational amplifiers can work in a power supply circuit of 3-32V, the offset current is small, and internal compensation can be realized. Therefore, the method is applied to more circuits.
In the invention, the power of the element needs to be determined by inquiring a data manual, so that the output damage caused by exceeding the output power is prevented, and the maximum power required by each element is generally influenced by the power of a required signal and an unnecessary noise signal; since noise is subject to various disturbances and an unnecessarily high power signal may appear, a slightly higher power element is selected.
The invention is connected to different filter circuits through different amplifying circuits, has different generating effects, larger variable range of output amplitude and higher flexibility, and realizes the functions of low-pass, high-pass, band-pass and band-stop filtering.
The above-described embodiment is only one of the embodiments that can implement the technical solution of the present invention, and the scope of the present invention is not limited by the embodiment, but includes any variations, substitutions and other embodiments that can be easily conceived by those skilled in the art within the technical scope of the present invention disclosed.
Claims (9)
1. A signal readout circuit is characterized by comprising an amplifying circuit and a filtering circuit; the input end of the amplifying circuit is connected with the input signal, and the output end of the amplifying circuit is connected with the input end of the filter circuit;
the amplifying circuit comprises a single carrier integrating circuit and a double carrier integrating circuit, the single carrier integrating circuit and the double carrier integrating circuit are arranged in parallel, the input end of the single carrier integrating circuit or the double carrier integrating circuit is connected with an input signal, and the output end of the single carrier integrating circuit or the double carrier integrating circuit is connected with the input end of the filter circuit;
the filter circuit comprises a low-pass filter, a high-pass filter, a band-stop filter and a band-pass filter; the low-pass filter, the high-pass filter, the band-stop filter and the band-pass filter are arranged in parallel; the input ends of the low-pass filter, the high-pass filter, the band-stop filter and the band-pass filter are respectively connected with the output end of the single carrier integrating circuit or the double carrier integrating circuit.
2. A signal readout circuit as claimed in claim 1, wherein a switch S1 is provided between the output of the single-carrier integrator and the input of the filter circuit, and a switch S2 is provided between the output of the dual-carrier integrator and the input of the filter circuit.
3. The signal readout circuit of claim 1, wherein the single carrier integrator circuit comprises an integrated operational amplifier U6A, an integrated operational amplifier U7A, an integrated operational amplifier U8A, a capacitor C8, a capacitor C9, a capacitor C10, a capacitor C11, a resistor R16, a resistor R17, a resistor R18, a resistor R19, and a resistor R20; the integrated operational amplifier U6A and the integrated operational amplifier U7A are arranged in parallel, the positive input end of the integrated operational amplifier U6A is grounded, and the positive input end of the integrated operational amplifier U7A is grounded;
the reverse input end of the integrated operational amplifier U6A is connected with an input signal through a capacitor C8, and a resistor R16 and a capacitor C9 are connected between the reverse input end and the output end of the integrated operational amplifier U6A in parallel; the output end of the integrated operational amplifier U6A is connected with the positive input end of the integrated operational amplifier U8A through a resistor R19;
the reverse input end of the integrated operational amplifier is connected with an input signal through a capacitor C10, and a capacitor C11 and a resistor R17 are arranged between the reverse input end and the output end of the integrated operational amplifier U7A in parallel; the output end of the integrated operational amplifier U7A is connected between the inverted input end of the integrated operational amplifier U8A through a resistor R18; one end of the resistor R20 is connected with the inverted input end of the integrated operational amplifier U8A, and the other end is connected with the output end of the integrated operational amplifier U8A.
4. A signal readout circuit according to claim 1, wherein the dual carrier integrator circuit comprises an integrated operational amplifier U5A, a capacitor C4, a capacitor C5 and a capacitor C6; one end of the capacitor C4 is connected with one end of an input signal, and the other end of the capacitor C4 is connected with the reverse input end of the integrated operational amplifier U5A; one end of the capacitor C5 is connected with the other end of the input signal, and the other end of the capacitor C5 is connected with the reverse input end of the integrated operational amplifier U5A; the positive input end of the integrated operational amplifier U5A is grounded, and the output end of the integrated operational amplifier U5A is connected with the input end of the amplifying circuit; one end of the capacitor C6 is connected with the inverted input end of the integrated operational amplifier U5A, and the other end is connected with the output end of the integrated operational amplifier U5A.
5. A signal readout circuit according to claim 4, wherein the capacitor C4 and the capacitor C5 are ceramic capacitors, and the capacitor C6 is an electrolytic capacitor.
6. A signal readout circuit according to claim 1, wherein the low pass filter comprises an integrated operational amplifier U2A, a resistor R4, a resistor R5 and a capacitor C3, one end of the resistor R5 is connected to the output terminal of the amplification circuit, and the other end of the resistor R5 is connected to the inverting input terminal of the integrated operational amplifier U2A; the capacitor C3 and the resistor R4 are connected in parallel between the inverting input terminal and the output terminal of the integrated operational amplifier U2A.
7. A signal readout circuit as claimed in claim 1 wherein the high pass filter comprises an integrated operational amplifier U1A, a capacitor C1, a resistor R3 and a resistor R1; the positive input end of the integrated operational amplifier U1A is grounded;
one end of the capacitor C1 is connected with the output end of the amplifying circuit, the other end of the capacitor C1 is connected with one end of the resistor R3, and the other end of the resistor R3 is connected with the reverse input end of the integrated operational amplifier U1A; one end of the resistor R1 is connected with the reverse input end of the integrated operational amplifier U1A, and the other end is connected with the output end of the integrated operational amplifier U1A.
8. A signal readout circuit as claimed in claim 1 wherein the bandpass filter comprises an integrated op-amp U1A, an integrated op-amp U3A, a capacitor C1, a capacitor C2, a resistor R1, a resistor R2, a resistor R3 and a resistor R6; one end of the capacitor C1 is connected with the output end of the amplifying circuit, the other end of the capacitor C1 is connected with one end of the resistor R3, and the other end of the resistor R3 is connected with the reverse input end of the integrated operational amplifier U1A;
the integrated operational amplifier U1A, the resistor R6 and the integrated operational amplifier U3A are sequentially connected in series, the output end of the integrated operational amplifier U1A is connected with one end of the resistor R6, and the other end of the resistor R6 is connected with the reverse input end of the integrated operational amplifier U3A; one end of the resistor R1 is connected with the reverse input end of the integrated operational amplifier U1A, and the other end of the resistor R1 is connected with the output end of the integrated operational amplifier U1A; the capacitor C2 and the resistor R2 are connected in parallel between the inverting input terminal and the output terminal of the integrated operational amplifier U3A.
9. A signal readout circuit according to claim 1, wherein the band-stop filter comprises an integrated operational amplifier U1A, an integrated operational amplifier U4A, a resistor R1, a resistor R7, a resistor R8 and a capacitor C1; one end of the capacitor C1 is connected with the output end of the amplifying circuit, the other end of the capacitor C1 is connected with one end of the resistor R3, and the other end of the resistor R3 is connected with the reverse input end of the integrated operational amplifier U1A;
one end of the resistor R1 is connected with the reverse input end of the integrated operational amplifier U1A, and the other end of the resistor R1 is connected with the output end of the integrated operational amplifier U1A; one end of the resistor R7 is connected with the output end of the integrated operational amplifier U1A, and the other end of the resistor R7 is connected with the reverse input end of the integrated operational amplifier U4A; one end of the resistor R8 is connected with the inverted input end of the integrated operational amplifier U4A, and the other end is connected with the output end of the integrated operational amplifier U4A.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011643480.5A CN112787606A (en) | 2020-12-30 | 2020-12-30 | Signal reading circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011643480.5A CN112787606A (en) | 2020-12-30 | 2020-12-30 | Signal reading circuit |
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| CN112787606A true CN112787606A (en) | 2021-05-11 |
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|---|---|---|---|---|
| CN114157964A (en) * | 2021-12-15 | 2022-03-08 | 科大讯飞股份有限公司 | Audio circuit and apparatus |
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