CN209823716U - Filtering low-noise amplifier circuit for communication - Google Patents
Filtering low-noise amplifier circuit for communication Download PDFInfo
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- CN209823716U CN209823716U CN201920926005.5U CN201920926005U CN209823716U CN 209823716 U CN209823716 U CN 209823716U CN 201920926005 U CN201920926005 U CN 201920926005U CN 209823716 U CN209823716 U CN 209823716U
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- inductor
- resistor
- wave filter
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Abstract
The utility model discloses a filtering low noise amplifier circuit for communication belongs to electronic circuit technical field, including first wave filter, second wave filter, first signal amplifier, second signal amplifier, first band-pass filtering module and second band-pass filtering module, a serial communication port, input signal is connected to the input of first band-pass filtering module, the output of first band-pass filtering module is connected the input of second band-pass filtering module, the output of second band-pass filtering module is connected the input of first wave filter, the output of first wave filter is connected the input of first signal amplifier, the output of first signal amplifier is connected the second wave filter, the output of second wave filter is connected second signal amplifier. The utility model discloses a two-stage filter can effectively reduce the noise, realizes low noise filtering function.
Description
Technical Field
The utility model belongs to the technical field of electronic circuit, concretely relates to filtering low noise amplifier circuit for communication.
Background
The interphone adopts local oscillation frequencies in different forms due to different working frequency bands, wherein the UHF frequency band adopts an ultra-inner difference local oscillation frequency, namely the frequency of a local oscillation signal is lower than the frequency of a useful signal by one intermediate frequency; the VHF band uses a superheterodyne local oscillator frequency, i.e. the local oscillator signal has a frequency that is one if higher than the frequency of the desired signal. Because the relationship between the local oscillator signal frequency and the useful signal frequency is different, the frequency band in which the interference signal acts is also different, that is, the frequency band in which the UHF-band interference signal acts is on the left side of the operating frequency band, and the frequency band in which the VHF-band interference signal acts is on the right side of the operating frequency band. Therefore, how to accurately distinguish the interference signals of the left side band and the right side band becomes a standard for measuring the quality of the filter circuit of the talkback system.
SUMMERY OF THE UTILITY MODEL
In order to solve the above problem, the utility model provides a: the utility model provides a filtering low noise amplifier circuit for communication, includes first wave filter, first signal amplifier, second wave filter, first band-pass filtering module and second band-pass filtering module, input signal is connected to the input of first band-pass filtering module, the output of first band-pass filtering module is connected the input of second band-pass filtering module, the output of second band-pass filtering module is connected the input of first wave filter, the output of first wave filter is connected the input of first signal amplifier, the output of first signal amplifier is connected the second wave filter, the output of second wave filter is connected the second signal amplifier.
Preferably, the first filter includes an inductor L3, an inductor L6, a capacitor C9 and a capacitor C10, the second filter includes an inductor L1, a capacitor C2 and a capacitor C3, the first signal amplifier includes a resistor R3, a resistor R4, a first transistor VD1 and a capacitor C11, the second signal amplifier includes a resistor R5, a resistor R6, a second transistor VD2 and a capacitor C13, the first band-pass filtering module includes a capacitor C1, an inductor L1 and a varactor D1, and the second band-pass filtering module includes a capacitor C2, an inductor L2 and a varactor D2; the capacitor C1 is connected to the inductor L1, the grounding inductor L4 and the capacitor C2, the other end of the inductor L1 is connected to the capacitor C5 and the capacitor C6, the other end of the capacitor C5 is connected to the other end of the capacitor C6, the resistor R1 and the negative electrode of the grounding varactor D1, and the other end of the resistor R1 is connected to the grounding capacitor C11, the grounding capacitor C12, the resistor R2 and the tuning voltage V1.
Preferably, the other end of the resistor R2 is connected to the cathodes of a capacitor C2, a capacitor C2 and a grounding varactor D2, the other end of the capacitor C2 is connected to the other end of the capacitor C2 and an inductor L2, the other end of the inductor L2 is connected to the other end of the capacitor C2, a grounding inductor L2 and a capacitor C2, the other end of the capacitor C2 is connected to the other end of the capacitor C2, the other end of the inductor L2 is connected to the grounding capacitor C2, the other end of the capacitor C2 is connected to the other end of the inductor L2 and the capacitor C2, the other end of the capacitor C2 is connected to the bases of the resistor R2 and a first transistor VD2, the collector of the first transistor VD2 is connected to the cathode of the first transistor VD2 and the ground, the other end of the capacitor C2 is connected to the second filter VD2, and the other end of the capacitor VD2 is connected to the, the output of second wave filter is resistance R5, second triode VD2 base is connected to resistance R5, and second triode VD2 collecting electrode is connecting resistance R5 and electric capacity C13 respectively, and direct current voltage VCC is connected to the resistance R5 other end, signal output part is connected to the electric capacity C13 other end.
Compared with the prior art, the beneficial effects of the utility model are that: the band-pass mode of band elimination and high pass is selected to obtain the steeper band-pass characteristic at the right side band so as to obtain larger out-of-band rejection, thereby improving the anti-interference capability; the two-stage filter can effectively reduce noise and realize the low-noise filtering function.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It is to be understood that the following description is exemplary only, and is not intended to limit the invention to the following embodiments.
FIG. 1 is a schematic block diagram of a filtered low noise amplifier circuit;
FIG. 2 is a circuit diagram of the present invention;
fig. 3 is a circuit diagram of a second filter.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the description is intended to be illustrative only and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.
Referring to fig. 1-3, the present invention provides a filtering lna circuit for communication, and the specific circuit and operation principle of the filtering lna circuit for communication will be explained below.
IN this embodiment, this low noise amplifier circuit of filtering for communication includes first wave filter, first signal amplifier, second wave filter, first band-pass filter module and second band-pass filter module, input signal IN is connected to the input of first band-pass filter module, the output of first band-pass filter module is connected the input of second band-pass filter module, the output of second band-pass filter module is connected the input of first wave filter, the output of first wave filter is connected the input of first signal amplifier, the output of first signal amplifier is connected the second wave filter, the output of second wave filter is connected the second signal amplifier.
Specifically, the first filter includes an inductor L3, an inductor L6, a capacitor C9 and a capacitor C10, the second filter includes an inductor L1, a capacitor C2 and a capacitor C3, the first signal amplifier includes a resistor R3, a resistor R4, a first transistor VD1 and a capacitor C11, the second signal amplifier includes a resistor R5, a resistor R6, a second transistor VD2 and a capacitor C13, the first band-pass filtering module includes a capacitor C1, an inductor L1 and a varactor D1, and the second band-pass filtering module includes a capacitor C2, an inductor L2 and a varactor D2; the capacitor C1 is respectively connected to the inductor L1, the grounding inductor L4 and the capacitor C2, the other end of the inductor L1 is respectively connected to the capacitor C5 and the capacitor C6, the other end of the capacitor C5 is respectively connected to the other end of the capacitor C6, the resistor R1 and the negative electrode of the grounding varactor D1, and the other end of the resistor R1 is respectively connected to the grounding capacitor C11, the grounding capacitor C12, the resistor R2 and the tuning voltage V1; the other end of the resistor R2 is respectively connected with the negative electrodes of a capacitor C2, a capacitor C2 and a grounding varactor D2, the other end of the capacitor C2 is respectively connected with the other end of the capacitor C2 and an inductor L2, the other end of the inductor L2 is respectively connected with the other end of the capacitor C2, the grounding inductor L2 and the capacitor C2, the other end of the capacitor C2 is respectively connected with the capacitor C2, the other end of the inductor L2 is respectively connected with the grounding capacitor C2, the other end of the capacitor C2 is respectively connected with the other end of the inductor L2 and the capacitor C2, the other end of the capacitor C2 is connected with the capacitor C2, the other end of the capacitor C2 is respectively connected with the base of the resistor R2 and the first triode VD2, the collector of the first triode 2 is respectively connected with the resistor R2 and the capacitor C2, the other end of the resistor R2 is connected with a direct current voltage VCC, the negative electrode of the power supply U2 is, the output of second wave filter is resistance R5, second triode VD2 base is connected to resistance R5, and second triode VD2 collecting electrode is connecting resistance R5 and electric capacity C13 respectively, and direct current voltage VCC is connected to the resistance R5 other end, signal output part is connected to the electric capacity C13 other end.
The band-pass mode of the first filter and the first band-pass filtering module is to obtain a steeper band-pass characteristic at the right side band so as to obtain larger out-of-band rejection, thereby improving the anti-interference capability; the series capacitor of the varactor is used for reducing tuning sensitivity so as to reduce the influence of voltage fluctuation on band-pass characteristics; the two capacitors are connected in parallel with the capacitor connected in series with the varactor so as to conveniently adjust the shape of the band-pass to increase the debugging redundancy; the series resonance band elimination filter is used for inhibiting image frequency interference, because certain image frequency points of the VHF frequency band just fall in a transition band of the antenna low-pass filter circuit and the band elimination filter circuit (the position of the image frequency is related to the size of the first intermediate frequency), the second band-pass filter circuit is used for inhibiting the degree of inhibition on the image frequency which is not enough to meet the requirement; the filter circuit is added with an amplifying module for amplifying the attenuated signals after filtering, and a first filter from one stage to the ground is added to the filter circuit for increasing the suppression degree of the right sideband of the band-pass.
In this embodiment, the input signal can effectively filter clutter interference in the signal through the first band-pass filtering module, the second band-pass filtering module, the first filter, the first signal amplifier and the second filter in sequence, and the stability of the signal is ensured.
It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.
Claims (3)
1. The utility model provides a low noise amplifier circuit of filtering for communication, includes first wave filter, second wave filter, first signal amplifier, second signal amplifier, first band-pass filtering module and second band-pass filtering module, its characterized in that, input signal is connected to the input of first band-pass filtering module, the output of first band-pass filtering module is connected the input of second band-pass filtering module, the output of second band-pass filtering module is connected the input of first wave filter, the output of first wave filter is connected the input of first signal amplifier, the output of first signal amplifier is connected the second wave filter, the output of second wave filter is connected the second signal amplifier.
2. The filtering low-noise amplifier circuit for communication of claim 1, wherein the first filter comprises an inductor L3, an inductor L6, a capacitor C9 and a capacitor C10, the second filter comprises an inductor L1, a capacitor C2 and a capacitor C3, the first signal amplifier comprises a resistor R3, a resistor R4, a first transistor VD1 and a capacitor C11, the second signal amplifier comprises a resistor R5, a resistor R6, a second transistor VD2 and a capacitor C13, the first band-pass filtering module comprises a capacitor C1, an inductor L1 and a varactor D1, and the second band-pass filtering module comprises a capacitor C2, an inductor L2 and a varactor D2; the capacitor C1 is connected to the inductor L1, the grounding inductor L4 and the capacitor C2, the other end of the inductor L1 is connected to the capacitor C5 and the capacitor C6, the other end of the capacitor C5 is connected to the other end of the capacitor C6, the resistor R1 and the negative electrode of the grounding varactor D1, and the other end of the resistor R1 is connected to the grounding capacitor C11, the grounding capacitor C12, the resistor R2 and the tuning voltage V1.
3. The circuit of claim 2, wherein the other end of the resistor R2 is connected to the negative electrodes of the capacitor C7, the capacitor C8 and the grounding varactor D2, the other end of the capacitor C7 is connected to the other end of the capacitor C8 and the inductor L2, the other end of the inductor L2 is connected to the other end of the capacitor C2, the inductor L2 is connected to the ground and the capacitor C2, the other end of the capacitor C2 is connected to the capacitor C2, the inductor L2 is connected to the inductor L2, the other end of the inductor L2 is connected to the ground, the other end of the capacitor C2 is connected to the other end of the inductor L2 and the capacitor C2, the other end of the capacitor C2 is connected to the bases of the resistor R2 and the first transistor VD2, the collector of the first transistor VD2 is connected to the resistor R2 and the capacitor C2, the other end of the power supply U2 is connected to the, the second wave filter is connected to the electric capacity C12 other end, the input is connected to the electric capacity C1 other end, and the output of second wave filter is resistance R5, second triode VD2 base is connected to resistance R5, and second triode VD2 collecting electrode is connecting resistance R5 and electric capacity C13 respectively, and direct current voltage VCC is connected to the resistance R5 other end, signal output part is connected to the electric capacity C13 other end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920926005.5U CN209823716U (en) | 2019-06-19 | 2019-06-19 | Filtering low-noise amplifier circuit for communication |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920926005.5U CN209823716U (en) | 2019-06-19 | 2019-06-19 | Filtering low-noise amplifier circuit for communication |
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| Publication Number | Publication Date |
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| CN209823716U true CN209823716U (en) | 2019-12-20 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201920926005.5U Expired - Fee Related CN209823716U (en) | 2019-06-19 | 2019-06-19 | Filtering low-noise amplifier circuit for communication |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113872634A (en) * | 2021-10-28 | 2021-12-31 | 广东宽普科技有限公司 | High-efficient stable communication circuit of VHF signal |
-
2019
- 2019-06-19 CN CN201920926005.5U patent/CN209823716U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113872634A (en) * | 2021-10-28 | 2021-12-31 | 广东宽普科技有限公司 | High-efficient stable communication circuit of VHF signal |
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Granted publication date: 20191220 Termination date: 20210619 |