CN202178740U - Low pass filter - Google Patents
Low pass filter Download PDFInfo
- Publication number
- CN202178740U CN202178740U CN2011203002138U CN201120300213U CN202178740U CN 202178740 U CN202178740 U CN 202178740U CN 2011203002138 U CN2011203002138 U CN 2011203002138U CN 201120300213 U CN201120300213 U CN 201120300213U CN 202178740 U CN202178740 U CN 202178740U
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- Prior art keywords
- filter
- operational amplifier
- resistance
- resistor
- low pass
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Abstract
The utility model discloses a low pass filter, which adopts a cascaded structure of one-pole filter and two Tow-Thomas second order filter units. The one-pole filter comprises an input end, an output end, an operational amplifier, a capacitor and a resistor. The operational amplifier is connected between the input end and the output end, a positive input end of the operational amplifier is connected with the ground, and the capacitor, the resistor and the operational amplifier are connected in parallel. Each Tow-Thomas second order filter unit comprises an input end, an output end, a first filter circuit, a second filter circuit, a resistor R1, a resistor R2 and a resistor R3. The input ends are connected with the resistor R3s which are connected with the first filter circuits, the resistor R1s and the second filter circuits in series sequentially. The second filter circuits are connected with the output ends, and the resistor R1s are connected between the R3s and the output ends in parallel. The low pass filter is less in feedback loops, good in stability, and capable of better filtering disturbance signals and noise signals out of band.
Description
Technical field:
The utility model relates to a kind of low pass filter, relates to a kind of fertile low pass filter now of five rank Barts that is used for Low Medium Frequency GPS receiver in particular.
Background technology:
The global location airmanship is related to national defense and military safety and has wide civilian prospect, becomes the focus of domestic research in recent years.But aspect the research and development of correlation reception machine chip, domestic level still lags far behind many developed countries such as the U.S..Therefore the design and the research of receiver chip have its own strategic significance.Around the channel of gps signal place a lot of stronger interference are arranged, be easy to generate serious harmonic distortion, synchronous signal is through the decay of atmosphere; When being received the antenna reception of machine; Power is-the 130dBm magnitude that signal and faint is to the very high requirement of handling property proposition of GPS receiver.Select the Low Medium Frequency structure can avoid the dc offset problem of zero-if architecture, but, still need image removing circuit, after image removing circuit, need carry out frequency band and select, outer interference signal and the noise signal of filtering band because mirror image disturbs still existence.Need this moment active low-pass filter to realize filtering, certain gain is provided simultaneously, receive so that amplitude output signal is fit to analog to digital converter.
The utility model content:
It is tunable that the purpose of the utility model provides a kind of cut-off frequency, the fertile low pass filter now of five rank Barts of band quality factor compensation, thereby outer interference signal and the noise signal of better filtering band.
The technological solution of the utility model is following:
Low pass filter, it is made up of single-pole filter and Tow-Thomas second-order filter unit.
In the technique scheme, described single-pole filter has one, and described Tow-Thomas second-order filter unit has two, and described single-pole filter adopts the structure of cascade to be connected with two Tow-Thomas second-order filter unit.
In the technique scheme; Described single-pole filter comprises input, output, operational amplifier, electric capacity and resistance; Said operational amplifier is connected between input and the output, the positive input terminal ground connection of operational amplifier, said electric capacity, resistance and operational amplifier parallel connection.
In the technique scheme, described Tow-Thomas second-order filter unit comprises input, output, first filter circuit, second filter circuit, resistance R 1, resistance R 2 and resistance R 3.Said input connects resistance R 3; Said R3 connect successively first filter circuit, resistance R 1 and second filter circuit; Said second filter circuit is connected with output; A parallelly connected resistance R 1 between said R3 and the output.
In the technique scheme, described first filter circuit comprises operational amplifier, electric capacity and resistance, the positive input terminal ground connection of operational amplifier, said electric capacity, resistance and operational amplifier parallel connection.
In the technique scheme; Described second filter circuit comprises operational amplifier, electric capacity and multiplier; The positive input terminal ground connection of operational amplifier, said electric capacity and operational amplifier parallel connection, said multiplier is connected on the parallel circuits of said electric capacity and operational amplifier.
The utility model beneficial effect is:
The low pass filter of the utility model, its filter type are selected the fertile low pass filter now of five rank Barts, and its passband is smooth, and stopband suppresses to reach requirement, and realizes easily.The structure of this low pass filter adopts a single-pole filter and two structures that the Tow-Thomas second-order filter is unit cascaded, and its feedback control loop is less, and stability is better, and is easy to tuning.
Description of drawings:
Below in conjunction with accompanying drawing the utility model is done further explanation:
Fig. 1 is the single-stage point filter circuit figure of the utility model;
Fig. 2 is the circuit diagram of the secondary filter unit of the utility model.
Embodiment:
The following stated is merely the preferred embodiment of the utility model, is not that scope to the utility model limits.
Described single-pole filter has one, and described Tow-Thomas second-order filter unit has two, and described single-pole filter adopts the structure of cascade to be connected with two Tow-Thomas second-order filter unit.
Described single-pole filter comprises input Vin1, output end vo ut1, operational amplifier A (s), capacitor C and resistance R 1; Said operational amplifier is connected between input and the output; The positive input terminal ground connection of operational amplifier, said electric capacity, resistance and operational amplifier parallel connection.
Described Tow-Thomas second-order filter unit comprises input Vin, output end vo ut, first filter circuit 100, second filter circuit 200, resistance R 1, resistance R 2 and resistance R 3.Said input connects resistance R 3; Said R3 connect successively first filter circuit, resistance R 1 and second filter circuit; Said second filter circuit is connected with output; A parallelly connected resistance R 1 between said R3 and the output.
Described first filter circuit comprises operational amplifier A (s), capacitor C and resistance R 2, the positive input terminal ground connection of operational amplifier, said electric capacity, resistance and operational amplifier parallel connection.
Described second filter circuit comprises operational amplifier A (s), capacitor C and multiplier, the positive input terminal ground connection of operational amplifier, and said electric capacity and operational amplifier parallel connection, said multiplier is connected on the parallel circuits of said electric capacity and operational amplifier.
Claims (5)
1. low pass filter, it is characterized in that: it is made up of single-pole filter and Tow-Thomas second-order filter unit; Described single-pole filter has one, and described Tow-Thomas second-order filter unit has two, and described single-pole filter adopts the structure of cascade to be connected with two Tow-Thomas second-order filter unit.
2. low pass filter according to claim 1; It is characterized in that: described single-pole filter comprises input, output, operational amplifier, electric capacity and resistance; Said operational amplifier is connected between input and the output; The positive input terminal ground connection of operational amplifier, said electric capacity, resistance and operational amplifier parallel connection.
3. low pass filter according to claim 1 is characterized in that: described Tow-Thomas second-order filter unit comprises input, output, first filter circuit, second filter circuit, resistance R 1, resistance R 2 and resistance R 3.Said input connects resistance R 3; Said R3 connect successively first filter circuit, resistance R 1 and second filter circuit; Said second filter circuit is connected with output; A parallelly connected resistance R 1 between said R3 and the output.
4. low pass filter according to claim 3 is characterized in that: described first filter circuit comprises operational amplifier, electric capacity and resistance, the positive input terminal ground connection of operational amplifier, said electric capacity, resistance and operational amplifier parallel connection.
5. low pass filter according to claim 4; It is characterized in that: described second filter circuit comprises operational amplifier, electric capacity and multiplier; The positive input terminal ground connection of operational amplifier; Said electric capacity and operational amplifier parallel connection, said multiplier is connected on the parallel circuits of said electric capacity and operational amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203002138U CN202178740U (en) | 2011-08-17 | 2011-08-17 | Low pass filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203002138U CN202178740U (en) | 2011-08-17 | 2011-08-17 | Low pass filter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202178740U true CN202178740U (en) | 2012-03-28 |
Family
ID=45868603
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011203002138U Expired - Fee Related CN202178740U (en) | 2011-08-17 | 2011-08-17 | Low pass filter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202178740U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106803749A (en) * | 2017-03-01 | 2017-06-06 | 贵州木弓贵芯微电子有限公司 | A kind of wave filter and its quality factor compensation method |
| CN109873620A (en) * | 2017-12-01 | 2019-06-11 | 炬芯（珠海）科技有限公司 | Third-order low-pass filter |
| CN117118433A (en) * | 2023-10-25 | 2023-11-24 | 成都九洲迪飞科技有限责任公司 | Novel high-order phase-locked loop system, loop filter circuit and implementation method |
| TWI834408B (en) * | 2022-12-02 | 2024-03-01 | 元智大學 | Two-stage filter |
-
2011
- 2011-08-17 CN CN2011203002138U patent/CN202178740U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106803749A (en) * | 2017-03-01 | 2017-06-06 | 贵州木弓贵芯微电子有限公司 | A kind of wave filter and its quality factor compensation method |
| CN109873620A (en) * | 2017-12-01 | 2019-06-11 | 炬芯（珠海）科技有限公司 | Third-order low-pass filter |
| CN109873620B (en) * | 2017-12-01 | 2023-08-29 | 炬芯科技股份有限公司 | Third-order low-pass filter |
| TWI834408B (en) * | 2022-12-02 | 2024-03-01 | 元智大學 | Two-stage filter |
| CN117118433A (en) * | 2023-10-25 | 2023-11-24 | 成都九洲迪飞科技有限责任公司 | Novel high-order phase-locked loop system, loop filter circuit and implementation method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120328 Termination date: 20140817 |
|
| EXPY | Termination of patent right or utility model |