CN202218204U - Multi-channel low pass filter - Google Patents
Multi-channel low pass filter Download PDFInfo
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- CN202218204U CN202218204U CN2011203274467U CN201120327446U CN202218204U CN 202218204 U CN202218204 U CN 202218204U CN 2011203274467 U CN2011203274467 U CN 2011203274467U CN 201120327446 U CN201120327446 U CN 201120327446U CN 202218204 U CN202218204 U CN 202218204U
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Abstract
The utility model discloses a multi-channel low pass filter including a power source module, a low pass filtering control module and at least one filtering module. The filtering module includes a filtering input channel module, an active low pass filtering module, a signal amplifying module, a switch capacitor filtering module and a filtering output channel module. The power source module connects with the low pass filtering control module, the active low pass filtering module, the signal amplifying module and the switch capacitor filtering module. The filtering input channel module connects with the active low pass filtering module. The active low pass filtering module connects with the signal amplifying module. The signal amplifying module connects with the switch capacitor filtering module. The low pass filtering control module connects with the switch capacitor filtering module. The switch capacitor filtering module connects with the filtering output channel module. The multi-channel low pass filter in the utility model has advantages of large noise margin, strong anti-interference capability, high precision, low limiting frequency, and low fluctuation aptitude and high stability in frequency response.
Description
Technical field
The utility model relates to a kind of low pass filter, especially relates to a kind of multichannel low pass filter.
Background technology
The multichannel low pass filter can transmit the useful frequency content in the input signal, decays or suppresses useless frequency content; Traditional multichannel low pass filter mainly contains Butterworth filter, Chebyshev filter and elliptic filter, and the three has different passbands and transition band characteristic; Elliptic filter is with respect to Butterworth filter, and its transition band is more precipitous, and phase-frequency characteristic is relatively poor; Chebyshev filter is with respect to Butterworth filter, and its transition band is narrower, and phase-frequency characteristic is also relatively poor; Along with safety in production field and the raising of monitoring signal filtering requirement in the detection range, the cut-off frequency of traditional multichannel low pass filter is higher relatively, and its filtering accuracy and stability more and more can not meet the demands; And Butterworth LPF has good Frequency Response on passband, has obtained development fast and uses widely at safety in production field such as bridge, dam, skyscraper, tunnel, highway, electric power, petrochemical industry, fire-fighting and HVAC and monitoring detection range.
Summary of the invention
The utility model technical problem to be solved provides that a kind of cut-off frequency is low, precision is high, amplitude fluctuation is little during frequency response, stability is high, is applicable to the multichannel low pass filter of safety in production field and monitoring detection range.
The utility model solves the problems of the technologies described above the technical scheme that is adopted: a kind of multichannel low pass filter; Comprise power module; Also comprise low-pass filtering control module and at least one road filtration module; Described filtration module comprises filtering input channel module, active low-pass filter module, signal amplification module, switch-capacitor filtering module and filtering output channel module; Described power module is connected with described low-pass filtering control module, described active low-pass filter module, described signal amplification module and described switch-capacitor filtering module respectively; The signal output part of described filtering input channel module is connected with the signal input part of described active low-pass filter module; The signal output part of described active low-pass filter module is connected with the signal input part of described signal amplification module; The signal output part of described signal amplification module is connected with the signal input part of described switch-capacitor filtering module, and the signal output part of described low-pass filtering control module is connected with the control end of described switch-capacitor filtering module, and the signal output part of described switch-capacitor filtering module is connected with described filtering output channel module.
Described active low-pass filter module is made up of the first amplifier chip, the second amplifier chip, first resistance, second resistance, first electric capacity, second electric capacity and first variable capacitance diode; The in-phase signal input of the described first amplifier chip is connected with an end of described first resistance; The other end of described first resistance is connected with the anode of described first variable capacitance diode; The minus earth of described first variable capacitance diode; The inversion signal input of the described first amplifier chip is connected with the signal output part of the described first amplifier chip; The signal output part of the described first amplifier chip is connected through the in-phase signal input of described second resistance with the described second amplifier chip; The in-phase signal input of the described second amplifier chip is through first capacity earth; The inversion signal input of the described second amplifier chip is connected with the signal output part of the described second amplifier chip; The inversion signal input of the described first amplifier chip is connected with the signal output part of the described second amplifier chip through described second electric capacity, and the negative voltage input of the negative voltage input of the described first amplifier chip and the described second amplifier chip inserts respectively-12V voltage, and the positive voltage input of the positive voltage input of the described first amplifier chip and the described second amplifier chip inserts respectively+12V voltage.
Described signal amplification module is made up of the 3rd amplifier chip, the 3rd resistance, the 4th resistance, first rheostat and the 3rd electric capacity; The in-phase signal input of described the 3rd amplifier chip is connected with described the 3rd resistance; The in-phase signal input of described the 3rd amplifier chip is through described the 3rd capacity earth; The inversion signal input of described the 3rd amplifier chip is through described the 4th grounding through resistance; The inversion signal input of described the 3rd amplifier chip is connected with the signal output part of described the 3rd amplifier chip through described first rheostat; The positive voltage input access+12V voltage of described the 3rd amplifier chip, the negative voltage input access-12V voltage of described the 3rd amplifier chip.
Described low-pass filtering control module is made up of first single row's pin terminal, second single row's pin terminal, the 3rd single row's pin terminal, the 4th single row's pin terminal, pin connector, microprocessor chip and peripheral circuit; Described first single row's pin terminal is connected with described microprocessor chip; Described second single row's pin terminal is connected with described microprocessor chip; The described the 3rd single row's pin terminal is connected with described microprocessor chip; The described the 4th single row's pin terminal is connected with described microprocessor chip, and described microprocessor chip is connected with described pin connector.
Described switch-capacitor filtering module is made up of switch-capacitor filtering chip and peripheral circuit.
Described power module is made up of voltage stabilizing circuit, the first inductance isolation and capacitor filter, the second inductance isolation and capacitor filter, the 3rd inductance isolation and capacitor filter, the 4th inductance isolation and capacitor filter, voltage conversion circuit and binding post, and described voltage stabilizing circuit is that voltage stabilizing chip and peripheral circuit are formed by model.
Be provided with the voltage follow module between described signal amplification module and the described switch-capacitor filtering module; The signal input part of described voltage follow module is connected with the signal output part of described signal amplification module; The signal output part of described voltage follow module is connected with the signal input part of described switch-capacitor filtering module, and the power input of described voltage follow module is connected with described power module.
Described voltage follow module is made up of four high guaily unit chip, the 6th resistance, the 7th resistance, the 8th resistance, the 4th electric capacity and second variable capacitance diode; The in-phase signal input of described four high guaily unit chip is through described the 8th grounding through resistance; The inversion signal input of described four high guaily unit chip is connected with an end of described the 7th resistance; The other end of described the 7th resistance is through described the 4th capacity earth; The inversion signal input of described four high guaily unit chip is connected with the signal output part of described four high guaily unit chip through described the 6th resistance; The signal output part of described four high guaily unit chip is connected with the anode of described second variable capacitance diode, the minus earth of described second variable capacitance diode.
Compared with prior art; The advantage of the utility model is: input signal is transferred to the active low-pass filter module through filtering input channel module; The active low-pass filter module is transferred to the signal amplification module with the voltage signal that receives, and after the signal amplification module amplifies, is transferred to the switch-capacitor filtering module, and low-pass filtering control module output PWM wave control signal is in the switch-capacitor filtering module; After the switch-capacitor filtering module compares coupling with the transmission signals of the signal amplification module that receives and PWM wave control signal; Suppress or the useless frequency content that decays, export useful frequency content, realize LPF to filtering output channel module; Wherein the active low-pass filter module adopts Bath water low-pass filter circuit to extract useful signal; Suppress the noise jamming in the input signal, the signal amplification module can amplify low frequency small-signal waveform, in the switch-capacitor filtering module, adopts LTC-1164 5CSW chip; Have higher angular frequency precision and lower temperature and float coefficient; Amplitude fluctuation when overcoming frequency response has advantages of higher stability, satisfies the demand of safety in production field and monitoring detection range; If between signal amplification module and switch-capacitor filtering module, the voltage follow module is set in addition, can play the isolation buffer effect, eliminate the influence of load variations, further enhanced stability to the output signal.
Description of drawings
Fig. 1 is the theory diagram of the utility model;
Fig. 2 is the circuit theory diagrams of the power module of the utility model;
Fig. 3 is the circuit theory diagrams of the filtering input channel module of the utility model;
Fig. 4 is the circuit theory diagrams of the active low-pass filter module of the utility model;
Fig. 5 is the circuit theory diagrams of the signal amplification module of the utility model;
Fig. 6 is the circuit theory diagrams of the low-pass filtering control module of the utility model;
Fig. 7 is the circuit theory diagrams of the switch-capacitor filtering module of the utility model;
Fig. 8 is the circuit theory diagrams of the filtering output channel module of the utility model;
Fig. 9 is the circuit theory diagrams of the voltage follow module of the utility model.
Embodiment
Embodiment describes in further detail the utility model below in conjunction with accompanying drawing.
As shown in Figure 1; A kind of multichannel low pass filter; Comprise power module 1; Low-pass filtering control module 6 and at least one road filtration module; Filtration module comprises filtering input channel module 2, active low-pass filter module 3, signal amplification module 4, switch-capacitor filtering module 7 and filtering output channel module 8, and power module 1 is connected with low-pass filtering control module 6, active low-pass filter module 3, signal amplification module 4 and switch-capacitor filtering module 7 respectively, and the signal output part of filtering input channel module 2 is connected with the signal input part of active low-pass filter module 3; The signal output part of active low-pass filter module 3 is connected with the signal input part of signal amplification module 4; The signal output part of signal amplification module 4 is connected with the signal input part of switch-capacitor filtering module 7, and the signal output part of low-pass filtering control module 6 is connected with the control end of switch-capacitor filtering module 7, and the signal output part of switch-capacitor filtering module 7 is connected with filtering output channel module 8.
In the above-mentioned specific embodiment; As shown in Figure 2; Power module 1 is made up of the binding post J1 of voltage stabilizing circuit 13, the isolation of first inductance and capacitor filter 9, the isolation of second inductance and capacitor filter 10, the isolation of the 3rd inductance and capacitor filter 11, the isolation of the 4th inductance and capacitor filter 12, voltage conversion circuit 14 and 6Pin; Voltage stabilizing circuit 13 is made up of voltage stabilizing chip U3 and peripheral circuit, and wherein voltage stabilizing chip U3 is that model is the integrated chip of L7805; The voltage output end of voltage stabilizing chip U3 is connected with low-pass filtering control module 6, and voltage conversion circuit 14 comprises eight respectively a resistance and the electronic circuit that electric capacity is formed by connecting, and each electronic circuit converts the current signal that receives into voltage signal+12Vna; + 12Vnb; + 12Vnc ,+12Vnd ,-12Vna;-12Vnb;-12Vnc ,-12Vnd (wherein n >=1) exports respectively, and power module 1 provides respectively that active low-pass filtering module 3, signal amplification module 4, low-pass filtering control module 6 and switch-capacitor filtering module 7 need ± 12V voltage and ± 5V voltage.
In the above-mentioned specific embodiment, as shown in Figure 3, filtering input channel module 2 is made up of the binding post J2 of 2pin, and binding post J2 inserts input signal Si nglen (wherein n >=1).
In the above-mentioned specific embodiment; As shown in Figure 4; Active low-pass filter module 3 adopts second order Butterworth filter circuit; Form by the first amplifier chip A1, the second amplifier chip A2, first resistance R 1, second resistance R 2, first capacitor C 1, second capacitor C 2 and the first variable capacitance diode D1; Wherein the first amplifier chip A1 and the second amplifier chip A2 are respectively the integrated chip that model is OP177; In-phase signal input+IN of the first amplifier chip A1 is connected with an end of first resistance R 1; The other end of first resistance R 1 inserts input signal Si nglen (wherein n >=1) and is connected with the anode of the first variable capacitance diode D1; The minus earth of the first variable capacitance diode D1, inversion signal input-IN of the first amplifier chip A1 is connected with the signal output part OUT of the first amplifier chip A1, and the signal output part OUT of the first amplifier chip A1 is connected with in-phase signal input+IN of the second amplifier chip A2 through second resistance R 2; In-phase signal input+IN of the second amplifier chip A2 is through first capacitor C, 1 ground connection; Inversion signal input-IN of the second amplifier chip A2 is connected with the signal output part OUT of the second amplifier chip A2, and inversion signal input-IN of the first amplifier chip A1 is connected with the signal output part OUT of the second amplifier chip A2 through second capacitor C 2, the signal output part OUT output signal FIRVinn (wherein n >=1) of the second amplifier chip A2; The negative voltage input V-of the negative voltage input V-of the first amplifier chip A1 and the second amplifier chip A2 inserts respectively-12V voltage, and the positive voltage input V+ of the positive voltage input V+ of the first amplifier chip A1 and the second amplifier chip A2 inserts respectively+12V voltage.
In the above-mentioned specific embodiment; As shown in Figure 5; Signal amplification module 4 is made up of the 3rd amplifier chip A3, the 3rd resistance R 3, the 4th resistance R 4, the first rheostat B1 and the 3rd capacitor C 3; Wherein the 3rd amplifier chip A3 is that model is the integrated chip of OP177; In-phase signal input+IN of the 3rd amplifier chip A3 is connected with an end of the 3rd resistance R 3; The other end of the 3rd resistance R 3 inserts the output signal FIRVinn (wherein n >=1) of active low-pass filtering module 3, and in-phase signal input+IN of the 3rd amplifier chip A3 is through the 3rd capacitor C 3 ground connection, and inversion signal input-IN of the 3rd amplifier chip A3 is through the 4th resistance R 4 ground connection; Inversion signal input-IN of the 3rd amplifier chip A3 is connected with the signal output part OUT of the 3rd amplifier chip A3 through the first rheostat B1; The signal output part OUT output signal FIRVoutn (wherein n >=1) of the 3rd amplifier chip A3, the positive voltage input V+ access+12V voltage of the 3rd amplifier chip A3, the negative voltage input V-access-12V voltage of the 3rd amplifier chip.
In the above-mentioned specific embodiment; As shown in Figure 6; Low-pass filtering control module 6 is made up of the single row's pin terminals P of the single row's pin terminals P of the single row's pin terminals P of first single row's pin terminals P 1, second the 2, the 3rd the 3, the 4th 4, pin connector P5, microprocessor chip U1 and peripheral circuit; Wherein first single row's pin terminals P 1, second single row's pin terminals P the 2, the 3rd single row's pin terminals P the 3 and the 4th single row's pin terminals P 4 is respectively the terminal that model is Header 8H; Pin connector P5 is that model is the pin connector of AVRISP10, and microprocessor chip U1 is that model is the integrated chip of Atmega128, and the pin8 of first single row's pin terminals P 1 ~ pin1 end is held corresponding connection with PB0 ~ PB7 of Atmega128 chip U1; The pin8 of second single row's pin terminals P 2 ~ pin1 end is connected with PC0 ~ PC7 end of Atmega128 chip U1; The pin8 of the 3rd single row's pin terminals P 3 ~ pin1 end is connected with PD0 ~ PD7 end of Atmega128 chip U1, and the pin8 of the 4th single row's pin terminals P 4 ~ pin1 end is connected the PB1 of Atmega128 chip U1 with PE0 ~ PE7 end of Atmega128 chip U1; PE0; PE1 and VCC end are connected with the respective ends of AVRISP10 pin connector P5 respectively, and wherein peripheral circuit mainly is made up of crystal oscillator Z1, the 9th resistance R 9 and the 5th capacitor C 5 of 4mHz, and the power end VCC of crystal oscillator Z1 connects the voltage output end of the voltage stabilizing chip U3 in the voltage stabilizing circuit 13; The output OUT of crystal oscillator Z1 connects the XTAL1 end of the chip U1 of Atmega128; One end of the 9th resistance R 9 is connected with an end of the 5th capacitor C 5, and its public connecting end inserts the RESET end of Atmega128 chip U1, the 9th resistance R 9 another termination VCC; The other end ground connection of the 5th capacitor C 5, Atmega128 chip U1 output PWM wave control signal control switch capacitor filtering module 7 is carried out filtering.
In the above-mentioned specific embodiment, like Fig. 7 and shown in Figure 8, switch-capacitor filtering module 7 is by the switch-capacitor filtering chip
U2 and peripheral circuit are formed; Wherein switch-capacitor filtering chip U2 is that model is the integrated chip of LTC-1164 5CSW; Filtering output channel module 8 is made up of the binding post J3 of 2pin, after switch-capacitor filtering module 7 receives the output signal of PWM wave control signal and signal amplification module 4 of low-pass filtering control module 6 transmission, after LTC-1164 5CSW chip U2 matees the output signal of the signal amplification module 4 that receives and PWM wave control signal; Export useful frequency content to binding post J3; Realize LPF, wherein the angular frequency precision of LTC-1164 5CSW chip U2 can reach 0.03%, and temperature is floated coefficient can reach 0.0002DB/ ℃.
In the above-mentioned specific embodiment; Can also be provided with voltage follow module 5 between signal amplification module 4 and the switch-capacitor filtering module 7; The power input of voltage follow module 5 is connected with power module 1, and the signal input part of voltage follow module 5 is connected with the signal output part of signal amplification module 4, and the signal output part of voltage follow module 5 is connected with the signal input part of switch-capacitor filtering module 7; Voltage follow module 5 receives the signal of signal amplification module 4 transmission; This signal is carried out isolation buffer, be transferred to after the influence of elimination load variations and carry out Filtering Processing in the switch-capacitor filtering module 7, further strengthened the precision and the stability of filtering signal; Voltage follow module 5 is made up of four high guaily unit chip A4, the 6th resistance R 6, the 7th resistance R 7, the 8th resistance R 8, the 4th capacitor C 4 and the second variable capacitance diode D2; Wherein four high guaily unit chip A4 is that model is the integrated chip of OP177; In-phase signal input+IN of four high guaily unit chip A4 is through the 8th resistance R 8 ground connection; Inversion signal input-IN of four high guaily unit chip A4 is connected with an end of the 7th resistance R 7; The other end of the 7th resistance R 7 is through the 4th capacitor C 4 ground connection; Inversion signal input-IN of four high guaily unit chip A4 is connected with the signal output part OUT of four high guaily unit chip A4 through the 6th resistance R 6, and the signal output part OUT of four high guaily unit chip A4 is connected with the anode of the second variable capacitance diode D2, the minus earth of the second variable capacitance diode D2.
Claims (8)
1. multichannel low pass filter; Comprise power module; It is characterized in that also comprising low-pass filtering control module and at least one road filtration module; Described filtration module comprises filtering input channel module, active low-pass filter module, signal amplification module, switch-capacitor filtering module and filtering output channel module; Described power module is connected with described low-pass filtering control module, described active low-pass filter module, described signal amplification module and described switch-capacitor filtering module respectively; The signal output part of described filtering input channel module is connected with the signal input part of described active low-pass filter module; The signal output part of described active low-pass filter module is connected with the signal input part of described signal amplification module; The signal output part of described signal amplification module is connected with the signal input part of described switch-capacitor filtering module, and the signal output part of described low-pass filtering control module is connected with the control end of described switch-capacitor filtering module, and the signal output part of described switch-capacitor filtering module is connected with described filtering output channel module.
2. a kind of multichannel low pass filter according to claim 1; It is characterized in that described active low-pass filter module is made up of the first amplifier chip, the second amplifier chip, first resistance, second resistance, first electric capacity, second electric capacity and first variable capacitance diode; The in-phase signal input of the described first amplifier chip is connected with an end of described first resistance; The other end of described first resistance is connected with the anode of described first variable capacitance diode; The minus earth of described first variable capacitance diode; The inversion signal input of the described first amplifier chip is connected with the signal output part of the described first amplifier chip; The signal output part of the described first amplifier chip is connected through the in-phase signal input of described second resistance with the described second amplifier chip; The in-phase signal input of the described second amplifier chip is through first capacity earth; The inversion signal input of the described second amplifier chip is connected with the signal output part of the described second amplifier chip; The inversion signal input of the described first amplifier chip is connected with the signal output part of the described second amplifier chip through described second electric capacity, and the negative voltage input of the negative voltage input of the described first amplifier chip and the described second amplifier chip inserts respectively-12V voltage, and the positive voltage input of the positive voltage input of the described first amplifier chip and the described second amplifier chip inserts respectively+12V voltage.
3. a kind of multichannel low pass filter according to claim 1; It is characterized in that described signal amplification module is made up of the 3rd amplifier chip, the 3rd resistance, the 4th resistance, first rheostat and the 3rd electric capacity; The in-phase signal input of described the 3rd amplifier chip is connected with described the 3rd resistance; The in-phase signal input of described the 3rd amplifier chip is through described the 3rd capacity earth; The inversion signal input of described the 3rd amplifier chip is through described the 4th grounding through resistance; The inversion signal input of described the 3rd amplifier chip is connected with the signal output part of described the 3rd amplifier chip through described first rheostat, the positive voltage input access+12V voltage of described the 3rd amplifier chip, the negative voltage input access-12V voltage of described the 3rd amplifier chip.
4. a kind of multichannel low pass filter according to claim 1; It is characterized in that described low-pass filtering control module is made up of first single row's pin terminal, second single row's pin terminal, the 3rd single row's pin terminal, the 4th single row's pin terminal, pin connector, microprocessor chip and peripheral circuit; Described first single row's pin terminal is connected with described microprocessor chip; Described second single row's pin terminal is connected with described microprocessor chip; The described the 3rd single row's pin terminal is connected with described microprocessor chip; The described the 4th single row's pin terminal is connected with described microprocessor chip, and described microprocessor chip is connected with described pin connector.
5. a kind of multichannel low pass filter according to claim 1 is characterized in that described switch-capacitor filtering module is made up of switch-capacitor filtering chip and peripheral circuit.
6. according to the described a kind of multichannel low pass filter of claim 1; It is characterized in that described power module is made up of voltage stabilizing circuit, the first inductance isolation and capacitor filter, the second inductance isolation and capacitor filter, the 3rd inductance isolation and capacitor filter, the 4th inductance isolation and capacitor filter, voltage conversion circuit and binding post, described voltage stabilizing circuit is that voltage stabilizing chip and peripheral circuit are formed by model.
7. according to each described a kind of multichannel low pass filter in the claim 1 ~ 6; It is characterized in that being provided with the voltage follow module between described signal amplification module and the described switch-capacitor filtering module; The signal input part of described voltage follow module is connected with the signal output part of described signal amplification module; The signal output part of described voltage follow module is connected with the signal input part of described switch-capacitor filtering module, and the power input of described voltage follow module is connected with described power module.
8. a kind of multichannel low pass filter according to claim 7; It is characterized in that described voltage follow module is made up of four high guaily unit chip, the 6th resistance, the 7th resistance, the 8th resistance, the 4th electric capacity and second variable capacitance diode; The in-phase signal input of described four high guaily unit chip is through described the 8th grounding through resistance; The inversion signal input of described four high guaily unit chip is connected with an end of described the 7th resistance; The other end of described the 7th resistance is through described the 4th capacity earth; The inversion signal input of described four high guaily unit chip is connected with the signal output part of described four high guaily unit chip through described the 6th resistance, and the signal output part of described four high guaily unit chip is connected with the anode of described second variable capacitance diode, the minus earth of described second variable capacitance diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203274467U CN202218204U (en) | 2011-09-02 | 2011-09-02 | Multi-channel low pass filter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203274467U CN202218204U (en) | 2011-09-02 | 2011-09-02 | Multi-channel low pass filter |
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| CN202218204U true CN202218204U (en) | 2012-05-09 |
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| CN2011203274467U Expired - Fee Related CN202218204U (en) | 2011-09-02 | 2011-09-02 | Multi-channel low pass filter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102355228A (en) * | 2011-09-02 | 2012-02-15 | 宁波杉工结构监测与控制工程中心有限公司 | Multi-channel lowpass filter |
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2011
- 2011-09-02 CN CN2011203274467U patent/CN202218204U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102355228A (en) * | 2011-09-02 | 2012-02-15 | 宁波杉工结构监测与控制工程中心有限公司 | Multi-channel lowpass filter |
| CN102355228B (en) * | 2011-09-02 | 2014-03-12 | 宁波杉工结构监测与控制工程中心有限公司 | Multi-channel lowpass filter |
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