CN207926548U - A kind of bandpass filter - Google Patents
A kind of bandpass filter Download PDFInfo
- Publication number
- CN207926548U CN207926548U CN201820011631.7U CN201820011631U CN207926548U CN 207926548 U CN207926548 U CN 207926548U CN 201820011631 U CN201820011631 U CN 201820011631U CN 207926548 U CN207926548 U CN 207926548U
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- resistance
- operational amplifier
- capacitance
- output end
- bandpass filter
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Abstract
The utility model discloses a kind of bandpass filters, it is characterised in that：Including second order high-pass filtering circuit, the second-order low-pass filter circuit that is connected with second order high-pass filtering circuit；The second order high-pass filtering circuit includes operational amplifier A 1, one end is grounded as the capacitance pole C1, P that signal input part, the other end are connected after capacitance C2 with the anode of operational amplifier A 1 after resistance R3, the diode D1 etc. that the poles N are connected with the tie point of capacitance C1 and capacitance C2.The interfering noise outside setting range can be isolated for the utility model, effectively eliminate interfering noise, improve communication effect.
Description
Technical field
The utility model is related to a kind of filter, in particular to a kind of bandpass filters.
Background technology
Filter can filter out other frequency signals other than specific frequency, be widely used in communication field, to carry
High speech quality.Such as generally use filter filters out other interference signals other than sound of speaking in telephonic communication system,
To improve speech quality.However it is not good enough to interference signal filter effect for filter used by existing communication system, leads
Speech quality is caused to be unable to reach demand.
Utility model content
The purpose of the utility model is to overcome conventional filters to the imperfect defect of interference signal filter effect, provides
A kind of bandpass filter.
The purpose of this utility model is achieved through the following technical solutions：A kind of bandpass filter, including second order high-pass filtering
Circuit, the second-order low-pass filter circuit being connected with second order high-pass filtering circuit；The second order high-pass filtering circuit includes operation
Amplifier A1, the capacitance that one end is connected after capacitance C2 with the anode of operational amplifier A 1 as signal input part, the other end
The diode D1 that the pole C1, P is grounded after resistance R3, the poles N are connected with the tie point of capacitance C1 and capacitance C2, is serially connected in diode
Resistance R2 between the poles N and the output end of operational amplifier A 1 of D1, is serially connected in the output end and diode of operational amplifier A 1
The resistance R1 that resistance R4 and one end between the poles P of D1 are connected with the anode of operational amplifier A 1, the other end is grounded；Institute
The output end for stating operational amplifier A 1 is connected with second-order low-pass filter circuit, and cathode is connected with the poles P of diode D1.
Further, the second-order low-pass filter circuit includes operational amplifier A 2, and one end is defeated with operational amplifier A 1
The resistance R5 that outlet is connected, the other end is connected after resistance R7 with the anode of operational amplifier A 2, one end and resistance R5 and
The capacitance C4 that the tie point of resistance R7 is connected, the other end is connected with the output end of operational amplifier A 2, simultaneously with capacitance C4 phases
The resistance R8 of connection, the capacitance C3 that one end is connected with the anode of operational amplifier A 2, the other end is grounded, is in parallel with capacitance C3
The resistance R6 and resistance R9 that one end is connected with the output end of operational amplifier A 2, the other end is grounded after resistance R10；Institute
The cathode for stating operational amplifier P2 is connected with the tie point of resistance R9 and resistance R10, its output end is as signal output end.
The centre frequency of the second order high-pass filtering circuit isThe second-order low-pass filter
The centre frequency of circuit is
The gain A of the second order high-pass filtering circuitF1Equal to the gain A of second-order low-pass filter circuitF2, i.e.,：The gain A of the bandpass filterF=AF1AF2。
The frequency filtering of the bandpass filter is 300~3000Hz.
The utility model compared with the prior art, has the following advantages and advantageous effect：The utility model can will be set
Interfering noise outside range is isolated, and interfering noise is effectively eliminated, and improves communication effect.
Description of the drawings
Fig. 1 is the overall structure diagram of the utility model.
Specific implementation mode
The utility model is described in further detail with reference to embodiment, but the embodiment of the utility model is simultaneously
It is without being limited thereto.
Embodiment
As shown in Figure 1, the bandpass filter of the utility model, including second order high-pass filtering circuit, with second order high-pass filtering
The second-order low-pass filter circuit that circuit is connected.The frequency filtering of the bandpass filter is 300~3000Hz, can be effective
It filters interfering noise and retains the audio signal spoken, to which the sound for making telephonic communication system export is more clear.
Specifically, the second order high-pass filtering circuit includes operational amplifier A 1, and capacitance C1, capacitance C2, resistance R1, resistance
R2, resistance R3, resistance R4 and diode D1.
When connection, one end of capacitance C1 with as signal input part, the other end after capacitance C2 with operational amplifier A 1
Anode be connected.The poles P of diode D1 are grounded after resistance R3, the poles N are connected with the tie point of capacitance C1 and capacitance C2.Electricity
Resistance R2 is serially connected between the poles N of diode D1 and the output end of operational amplifier A 1.Resistance R4 is serially connected in operational amplifier A 1
Between output end and the poles P of diode D1.One end of resistance R1 is connected with the anode of operational amplifier A 1, the other end is grounded.
The output end of the operational amplifier A 1 is connected with second-order low-pass filter circuit, and cathode is connected with the poles P of diode D1.
Signal input inputs to operational amplifier A 1 after coming in after capacitance C1 and capacitance C2 are filtered, the operation amplifier
High-pass filter is collectively formed in device A1, capacitance C1, capacitance C2, resistance R4 and resistance R3；The operational amplifier A 1 is negative-feedback,
It can be with the gain of stabilizing circuit.The centre frequency of the second order high-pass filtering circuit isAt this
In embodiment, the capacitance of capacitance C1 and capacitance C2 is that the resistance value of 0.068 μ F, resistance R1 and resistance R2 are 8.2K Ω；By
Above-mentioned formula can obtain, the centre frequency f of second order high-pass filtering circuit in the present embodiment1=286Hz.In addition, diode D1
The resistance value of model 14001, resistance R4 is 27K Ω, and the resistance value of resistance R3 is 47K Ω, the model OP07 of operational amplifier A 1.
The audio signal that operational amplifier A 1 exports is input to second-order low-pass filter circuit.
As shown in Figure 1, the second-order low-pass filter circuit includes operational amplifier A 2, and resistance R5, resistance R7, resistance R6, electricity
Hinder R8, resistance R9, resistance R10, capacitance C3 and capacitance C4.When specific connection, one end and the operational amplifier A 1 of resistance R5
Output end be connected, the other end is connected after resistance R7 with the anode of operational amplifier A 2.One end of capacitance C4 and resistance
The tie point of R5 and resistance R7 are connected, the other end is connected with the output end of operational amplifier A 2.Resistance R8 and capacitance C4 phases
It is in parallel.One end of capacitance C3 is connected with the anode of operational amplifier A 2, the other end is grounded.Resistance R6 is in parallel with capacitance C3.
One end of resistance R9 is connected with the output end of operational amplifier A 2, the other end is grounded after resistance R10.The operational amplifier
The cathode of P2 is connected with the tie point of resistance R9 and resistance R10, its output end is then as the output end of signal.
The audio signal that operational amplifier A 1 exports inputs to operational amplifier A 2, while electricity after resistance R5 and resistance R7
Audio signal can be filtered by holding C3 and capacitance C4；The operational amplifier A 2, resistance R5, resistance R7, capacitance C3, resistance R6,
Low-pass filter is collectively formed in capacitance C4 and resistance R8.Operational amplifier A 2 is also negative-feedback, can be with the increasing of stabilizing circuit
Benefit.The centre frequency of the second-order low-pass filter circuit isIn the present embodiment, resistance R5 and
The resistance value of resistance R7 is that the capacitance of 8.2K Ω, capacitance C3 and capacitance C4 are 0.0068 μ F；It can be obtained by above-mentioned formula, this reality
Apply the centre frequency f of second-order low-pass filter circuit in example2=2856Hz.In addition, the resistance value of resistance R6 is 10K Ω, resistance R8
Resistance value be 1K Ω, the resistance value of resistance R9 is 27K Ω, and the resistance value of resistance R10 is 47K Ω, the model of operational amplifier A 2
OP07。
It is obtained by above-mentioned, the cutoff frequency of the bandwidth-limited circuit of the present embodiment is 286Hz~2856Hz, to effective
Interference signal other than one's voice in speech frequency signal is isolated, speech quality is improved.
In addition, the gain A of the second order high-pass filtering circuitF1Equal to the gain A of second-order low-pass filter circuitF2, i.e.,：The gain A of the bandwidth-limited circuitF=AF1AF2。
As described above, the utility model can be realized well.
Claims (5)
1. a kind of bandpass filter, it is characterised in that：Including second order high-pass filtering circuit, it is connected with second order high-pass filtering circuit
Second-order low-pass filter circuit；The second order high-pass filtering circuit includes operational amplifier A 1, and one end is as signal input part, another
The capacitance pole C1, P that one end is connected after capacitance C2 with the anode of operational amplifier A 1 is grounded after resistance R3, the poles N and capacitance
The diode D1 that C1 is connected with the tie point of capacitance C2 is serially connected in the output end of the poles N and operational amplifier A 1 of diode D1
Between resistance R2, the resistance R4 being serially connected between the output end of operational amplifier A 1 and the poles P of diode D1 and one end with
The resistance R1 that the anode of operational amplifier A 1 is connected, the other end is grounded；The output end of the operational amplifier A 1 is low with second order
Bandpass filter circuit is connected, and cathode is connected with the poles P of diode D1.
2. a kind of bandpass filter according to claim 1, it is characterised in that：The second-order low-pass filter circuit includes fortune
Calculate amplifier A2, one end is connected with the output end of operational amplifier A 1, the other end after resistance R7 with operational amplifier A 2
The resistance R5 that anode is connected, one end is connected with the tie point of resistance R5 and resistance R7, the other end and operational amplifier A 2
The capacitance C4 that output end is connected, the resistance R8 being in parallel with capacitance C4, one end is connected, separately with the anode of operational amplifier A 2
The capacitance C3 of one end ground connection, the resistance R6 and one end being in parallel with capacitance C3 be connected with the output end of operational amplifier A 2,
The resistance R9 that the other end is grounded after resistance R10；The tie point of the cathode and resistance R9 and resistance R10 of the operational amplifier P2
It is connected, its output end is as signal output end.
3. a kind of bandpass filter according to claim 2, it is characterised in that：The centre frequency of the second order high-pass filtering circuit
ForThe centre frequency of the second-order low-pass filter circuit is
4. a kind of bandpass filter according to claim 3, it is characterised in that：The gain of the second order high-pass filtering circuit
AF1Equal to the gain A of second-order low-pass filter circuitF2, i.e.,：The gain A of the bandpass filterF=
AF1AF2。
5. a kind of bandpass filter according to claim 4, it is characterised in that：The frequency filtering of the bandpass filter is
300~3000Hz.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820011631.7U CN207926548U (en) | 2018-01-04 | 2018-01-04 | A kind of bandpass filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820011631.7U CN207926548U (en) | 2018-01-04 | 2018-01-04 | A kind of bandpass filter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207926548U true CN207926548U (en) | 2018-09-28 |
Family
ID=63615980
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820011631.7U Expired - Fee Related CN207926548U (en) | 2018-01-04 | 2018-01-04 | A kind of bandpass filter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207926548U (en) |
-
2018
- 2018-01-04 CN CN201820011631.7U patent/CN207926548U/en not_active Expired - Fee Related
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| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20180928 Termination date: 20190104 |
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| CF01 | Termination of patent right due to non-payment of annual fee |