CN103973252A - High-Q-factor band-pass filter for audio near field communication - Google Patents
High-Q-factor band-pass filter for audio near field communication Download PDFInfo
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- CN103973252A CN103973252A CN201310043101.2A CN201310043101A CN103973252A CN 103973252 A CN103973252 A CN 103973252A CN 201310043101 A CN201310043101 A CN 201310043101A CN 103973252 A CN103973252 A CN 103973252A
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Abstract
The invention discloses a high-Q-factor band-pass filter for audio near field communication. The band-pass filter comprises a first amplifier, a second amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a first capacitor, a second capacitor and a third capacitor, wherein the first amplifier, the first, second and third resistors and the first and second capacitors jointly form a first-stage general filter low in Q-value, the second amplifier, the sixth and seventh resistors and the third capacitor jointly form a second-stage phase inverter which amplifies signals by several times to increase the Q-value of an entire circuit, and the fifth resistor is a feedback resistance which leads part of positive feedback of the second stage into the first stage. The band-pass filter has good frequency-selection characteristics. The Q-value of the circuit is increased, so that the band-pass filter is narrow in bandwidth and good in frequency-selection characteristics and has good anti-jamming capability.
Description
Technical field
The present invention relates to a kind of band pass filter, relate in particular to a kind of high Q matter band pass filter paying for audio frequency near field.
Background technology
Audio frequency near field payment technology be the applicant's a kind of utilization of proposing and applying for a patent closely audio transmission information to complete the technology of payment function, it utilizes the audio frequency R-T unit realization that the conventional equipments such as mobile phone carry to pay, and has advantages of and pays quick, easily enforcement, easily universal.In the payment technology of audio frequency near field, in the receipts of audio frequency, in the process of sending out, all need to use band pass filter, although traditional band pass filter has without inductance, volume is little, lightweight, the open-loop voltage gain of integrated transporting discharging and input impedance are all very high, output impedance is low again, after forming active filter circuit, also there is certain advantage such as voltage amplification and cushioning effect, but because of its Q value (being quality factor) cannot do very large, what also just cause that its passband width cannot do is very narrow, having caused this filter is not fine to the selectivity of frequency, neither be very strong to the inhibition ability of interference signal.
Summary of the invention
Object of the present invention is just to provide in order to address the above problem a kind of high Q matter band pass filter paying for audio frequency near field.
The present invention is achieved through the following technical solutions above-mentioned purpose:
The high Q matter band pass filter paying for audio frequency near field of the present invention, comprises the first amplifier, the second amplifier, the first resistance, the second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, the first electric capacity, the second electric capacity and the 3rd electric capacity, the first end of described the first resistance respectively with the first end of described the second resistance, the second end of described the 5th resistance, the first end of described the first electric capacity is connected with the first end of described the second electric capacity, the second end of described the second electric capacity is connected with the first end of described the 3rd resistance and the negative input of described the first amplifier respectively, the second end of described the first electric capacity respectively with the second end of described the 3rd resistance, the output of described the first amplifier is connected with the first end of described the 4th resistance, the second end of described the 4th resistance respectively with the negative input of described the second amplifier, the first end of described the 6th resistance is connected with the first end of described the 3rd electric capacity, and the electrode input end of described the second amplifier is connected with the first end of described the 7th resistance, the output of described the second amplifier respectively with the second end of described the 5th resistance, the second end of described the 6th resistance is connected with the second end of described the 3rd electric capacity, the second end of described the second resistance, the second end of the electrode input end of described the first amplifier and described the 7th resistance interconnects, the electrode input end that the second end of described the first resistance is described band pass filter, the output of described the second amplifier is the cathode output end of described band pass filter, and the electrode input end of described the first amplifier is negative input and the cathode output end of described band pass filter simultaneously.
As preferably, described the first amplifier and described the second amplifier are high input impedance type integrated operational amplifier.
Beneficial effect of the present invention is:
The first amplifier of the present invention, the first resistance, the second resistance, the 3rd resistance, the first electric capacity and the second electric capacity form first order general filter jointly, and its Q value is lower; The second amplifier, the 6th resistance, the 7th resistance and the 3rd electric capacity form second level inverter jointly, and signal is amplified to several times, improve the Q value of whole circuit; The 5th resistance is feedback resistance, the partial positive feedback of the second level is introduced to the first order, so band pass filter of the present invention has good selecting frequency characteristic.The present invention, by improving Q-Value in Electric Circuit, makes that its bandwidth is narrower and selecting frequency characteristic good, and has good antijamming capability.
Brief description of the drawings
Fig. 1 is the circuit diagram of high Q matter band pass filter of the present invention;
Fig. 2 is the system architecture diagram of sound intermediate frequency of the present invention near field payment system;
Fig. 3 is the circuit structure block diagram of the voice frequency sender of sound intermediate frequency of the present invention near field payment system;
Fig. 4 is the circuit structure block diagram of the audio receiver of sound intermediate frequency of the present invention near field payment system.
Embodiment
Below in conjunction with accompanying drawing, the invention will be further described:
As shown in Figure 2, Figure 3 and Figure 4, audio frequency near field payment system in the payment technology of audio frequency near field comprises that multiple (in Fig. 2, having illustrated 4) can be mutually by the voice frequency terminal of voice communication, this voice frequency terminal can be the mobile terminals such as mobile phone, can be also the fixed terminals such as payment platform.Each voice frequency terminal comprises voice frequency sender and audio receiver, voice frequency sender comprises encoder for convolution codes, modulator, band pass filter, D/A change-over circuit, amplifirer and the loud speaker of series connection successively, the input input Applied Digital data-signal of encoder for convolution codes, the information medium of loud speaker output sound signal for paying as near field; Audio receiver comprises microphone, A/D change-over circuit, band pass filter, demodulator, low pass filter and the convolutional code decoder device of series connection successively, the voice signal that the input of the input of microphone is transmitted by loud speaker, the output output Applied Digital data-signal of convolutional code decoder device.
As shown in Figure 1, above-mentioned band pass filter comprises the first amplifier A1, the second amplifier A2, the first resistance R 1, the second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6, the 7th resistance R 7, the first capacitor C 1, the first end of the second capacitor C 2 and the 3rd capacitor C 3, the first resistance R 1 respectively with the first end of the second resistance R 2, the second end of the 5th resistance R 5, the first end of the first capacitor C 1 is connected with the first end of the second capacitor C 2, and the second end of the second capacitor C 2 is connected with the first end of the 3rd resistance R 3 and the negative input of the first amplifier A1 respectively, the second end of the first capacitor C 1 respectively with the second end of the 3rd resistance R 3, the output of the first amplifier A1 is connected with the first end of the 4th resistance R 4, the second end of the 4th resistance R 4 respectively with the negative input of the second amplifier A2, the first end of the 6th resistance R 6 is connected with the first end of the 3rd capacitor C 3, and the electrode input end of the second amplifier A2 is connected with the first end of the 7th resistance R 7, the output of the second amplifier A2 respectively with the second end of the 5th resistance R 5, the second end of the 6th resistance R 6 is connected with the second end of the 3rd capacitor C 3, the second end of the second resistance R 2, the second end of the electrode input end of the first amplifier A1 and the 7th resistance R 7 interconnects, the electrode input end that the second end of the first resistance R 1 is described band pass filter, the output of the second amplifier A2 is the cathode output end of described band pass filter, and the electrode input end of the first amplifier A1 is negative input and the cathode output end of described band pass filter simultaneously, in figure, the second end of the first resistance R 1 and the electrode input end of the first amplifier A1 form the input Uin of described band pass filter, the electrode input end of the output of the second amplifier A2 and the first amplifier A1 forms the output Uout of described band pass filter, and input Uin and output Uout in figure are all labeled in positive pole.Above-mentioned the first amplifier A1 and the second amplifier A2 are high input impedance type integrated operational amplifier.
As shown in Figure 1, the first amplifier A1, the first resistance R 1, the second resistance R 2, the 3rd resistance R 3, the first capacitor C 1 and the common composition first order of the second capacitor C 2 general filter, its Q value is lower; The second amplifier A2, the 6th resistance R 6, the 7th resistance R 7 and the common composition of the 3rd capacitor C 3 second level inverter, amplify several times by signal, improves the Q value of whole circuit; The 5th resistance R 5 is feedback resistance, the partial positive feedback of the second level is introduced to the first order, so band pass filter of the present invention has good selecting frequency characteristic and antijamming capability.
Claims (2)
1. the high Q matter band pass filter paying for audio frequency near field, is characterized in that: comprise the first amplifier, the second amplifier, the first resistance, the second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, the first electric capacity, the second electric capacity and the 3rd electric capacity, the first end of described the first resistance respectively with the first end of described the second resistance, the second end of described the 5th resistance, the first end of described the first electric capacity is connected with the first end of described the second electric capacity, the second end of described the second electric capacity is connected with the first end of described the 3rd resistance and the negative input of described the first amplifier respectively, the second end of described the first electric capacity respectively with the second end of described the 3rd resistance, the output of described the first amplifier is connected with the first end of described the 4th resistance, the second end of described the 4th resistance respectively with the negative input of described the second amplifier, the first end of described the 6th resistance is connected with the first end of described the 3rd electric capacity, and the electrode input end of described the second amplifier is connected with the first end of described the 7th resistance, the output of described the second amplifier respectively with the second end of described the 5th resistance, the second end of described the 6th resistance is connected with the second end of described the 3rd electric capacity, the second end of described the second resistance, the second end of the electrode input end of described the first amplifier and described the 7th resistance interconnects, the electrode input end that the second end of described the first resistance is described band pass filter, the output of described the second amplifier is the cathode output end of described band pass filter, and the electrode input end of described the first amplifier is negative input and the cathode output end of described band pass filter simultaneously.
2. the high Q matter band pass filter paying for audio frequency near field according to claim 1, is characterized in that: described the first amplifier and described the second amplifier are high input impedance type integrated operational amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310043101.2A CN103973252A (en) | 2013-02-04 | 2013-02-04 | High-Q-factor band-pass filter for audio near field communication |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201310043101.2A CN103973252A (en) | 2013-02-04 | 2013-02-04 | High-Q-factor band-pass filter for audio near field communication |
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| CN103973252A true CN103973252A (en) | 2014-08-06 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201310043101.2A Pending CN103973252A (en) | 2013-02-04 | 2013-02-04 | High-Q-factor band-pass filter for audio near field communication |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104485920A (en) * | 2014-12-02 | 2015-04-01 | 苏州沃斯麦机电科技有限公司 | Signal processing system based on high-Q-value band pass filter circuit |
| CN106788325A (en) * | 2016-12-28 | 2017-05-31 | 宁波斯凯勒智能科技有限公司 | A kind of high q-factor tunable filter circuit |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070229152A1 (en) * | 2006-04-03 | 2007-10-04 | Kabushiki Kaisha Toshiba | Filter adjustment circuit |
| CN102364493A (en) * | 2011-10-18 | 2012-02-29 | 山东华翼微电子技术有限责任公司 | Novel high-frequency communication protocol monitoring circuit |
| CN203104383U (en) * | 2013-02-04 | 2013-07-31 | 成都摩宝网络科技有限公司 | High Q quality band pass filter used for audio frequency near field payment |
-
2013
- 2013-02-04 CN CN201310043101.2A patent/CN103973252A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070229152A1 (en) * | 2006-04-03 | 2007-10-04 | Kabushiki Kaisha Toshiba | Filter adjustment circuit |
| CN102364493A (en) * | 2011-10-18 | 2012-02-29 | 山东华翼微电子技术有限责任公司 | Novel high-frequency communication protocol monitoring circuit |
| CN203104383U (en) * | 2013-02-04 | 2013-07-31 | 成都摩宝网络科技有限公司 | High Q quality band pass filter used for audio frequency near field payment |
Non-Patent Citations (1)
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| 耿爽: "音频前置放大电路性能优化设计", 《火力与指挥控制》, vol. 28, 30 June 2003 (2003-06-30) * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104485920A (en) * | 2014-12-02 | 2015-04-01 | 苏州沃斯麦机电科技有限公司 | Signal processing system based on high-Q-value band pass filter circuit |
| CN106788325A (en) * | 2016-12-28 | 2017-05-31 | 宁波斯凯勒智能科技有限公司 | A kind of high q-factor tunable filter circuit |
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Application publication date: 20140806 |