CN106603033B

CN106603033B - Intermediate frequency 46.52MHz band-pass filter for Beidou

Info

Publication number: CN106603033B
Application number: CN201611272258.2A
Authority: CN
Inventors: 王冬梅
Original assignee: Shaanxi Fenghuo Electronics Co Ltd
Current assignee: Shaanxi Fenghuo Electronics Co Ltd
Priority date: 2016-12-31
Filing date: 2016-12-31
Publication date: 2023-09-22
Anticipated expiration: 2036-12-31
Also published as: CN106603033A

Abstract

The invention relates to an intermediate frequency 46.52MHz band-pass filter for Beidou, which comprises an input end, an output end and a grounding end, wherein a first inductor and a first capacitor are arranged between the input end and the grounding end in parallel; a second inductor and a second capacitor are connected in series between the input end and the output end; the output end is connected with a third inductor and a third capacitor which are arranged between the output end and the grounding end in parallel; the output end is connected with the fourth inductor and the fourth capacitor in series, and then a fifth inductor and a fifth capacitor are arranged between the output end and the grounding end in parallel; the output end is connected with the sixth inductor and the sixth capacitor in series, and then a seventh inductor and a seventh capacitor are arranged between the output end and the grounding end in parallel; the output end is connected with the eighth inductor and the eighth capacitor in series, and the ninth inductor and the ninth capacitor are connected in parallel and arranged between the output end and the grounding end. The invention can filter out-of-band clutter of the intermediate frequency output signal of the B3 frequency point of the Beidou user machine radio frequency unit, the passband width is more than or equal to 20MHz, the stopband attenuation is more than or equal to 60dB, and the in-band fluctuation is less than or equal to 1dB.

Description

Intermediate frequency 46.52MHz band-pass filter for Beidou

Technical Field

The invention belongs to the technical field of satellite communication, relates to a Beidou navigation user machine, and in particular relates to an intermediate frequency 46.52MHz band-pass filter for the Beidou user machine.

Background

In general, the intermediate frequency band-pass filter for Beidou is used for filtering out-of-band clutter of intermediate frequency output signals of the radio frequency unit B3 of the Beidou user machine. But the filter is characterized by a broader passband and a higher out-of-band rejection requirement, with a maximum rejection ratio requirement greater than 60dB. Meanwhile, the transition band is smaller, wherein the intermediate frequency of B3 is 6MHz, so that the difficulty of effective filtering is very high. Secondly, the filter has small volume, and the design and implementation difficulties of the filter are increased. There are various filters in the current market but the filtering effect is not good.

Disclosure of Invention

In order to solve the problems, the chebyshev band-pass filter is selected by comparing, optimizing and comprehensively considering, and is characterized by having equal ripple in the band and monotonously decreasing attenuation in the band, and can meet the index requirement of the intermediate frequency filter.

The invention aims to provide an intermediate frequency 46.52MHz band-pass filter for Beidou, and L, C lumped elements are selected to realize network parameters.

The technical scheme adopted by the invention is as follows:

the intermediate frequency 46.52MHz band-pass filter for Beidou comprises an input end, an output end and a grounding end; a first inductor and a first capacitor are arranged between the input end and the grounding end in parallel and are arranged between the input end and the grounding end; a second inductor and a second capacitor are connected in series between the input end and the output end; the output end is connected with a third inductor and a third capacitor which are arranged between the output end and the grounding end in parallel; the output end is connected with the fourth inductor and the fourth capacitor in series, and then a fifth inductor and a fifth capacitor are arranged between the output end and the grounding end in parallel; the output end is connected with the sixth inductor and the sixth capacitor in series, and then a seventh inductor and a seventh capacitor are arranged between the output end and the grounding end in parallel; the output end is connected with the eighth inductor and the eighth capacitor in series, and the ninth inductor and the ninth capacitor are connected in parallel and arranged between the output end and the grounding end.

The beneficial effects of the invention are as follows: the intermediate frequency 46.52MHz band-pass filter can be well applied to filtering out-of-band clutter of intermediate frequency output signals of the B3 frequency points of the Beidou user machine radio frequency unit, and has a good effect. The index of the filter is mainly that the passband width of the filter is more than or equal to 20MHz, the stopband attenuation is more than or equal to 60dB, the insertion loss is less than or equal to 3dB, the in-band fluctuation is less than or equal to 1dB, and the transition band is less than or equal to 6MHz.

Drawings

Fig. 1 is a schematic structural diagram of a bandpass filter of intermediate frequency 46.52MHz for Beidou according to the present invention.

In the figure, L1-a first inductor, C1-a first capacitor, L2-a second inductor, C2-a second capacitor, L3-a third inductor, C3-a third capacitor, L4-a fourth inductor, C4-a fourth capacitor, L5-a fifth inductor, C5-a fifth capacitor, L6-a sixth inductor, C6-a sixth capacitor, L7-a seventh inductor, C7-a seventh capacitor, L8-an eighth inductor, C8-an eighth capacitor, L9-a ninth inductor, C9-a ninth capacitor, A-an input end, B-an output end and C-a ground end.

Detailed Description

The present invention will be described in detail with reference to specific examples.

As shown in FIG. 1, the structure diagram of the intermediate frequency 46.52MHz band-pass filter for Beidou comprises an input end A, an output end B and a grounding end C; a first inductor L1 and a first capacitor C1 are arranged between the input end A and the grounding end C in parallel and are arranged between the input end A and the grounding end C; a second inductor L2 is connected in series with a second capacitor C2 between the input end A and the output end B; the output end B is connected with the third inductor L3 and the third capacitor C3 and is arranged between the output end B and the grounding end C in parallel; the output end B is connected with the fourth inductor L4 and the fourth capacitor C4 in series, and then a fifth inductor L5 and a fifth capacitor C5 are connected in parallel and arranged between the output end B and the grounding end C; the output end B is connected with a sixth inductor L6 and a sixth capacitor C6 in series, and a seventh inductor L7 and a seventh capacitor C7 are arranged between the output end B and the grounding end C in parallel; the output end B is connected with the eighth inductor L8 and the eighth capacitor C8 in series, and then a ninth inductor L9 and a ninth capacitor C9 are connected in parallel and arranged between the output end B and the grounding end C.

The values of the electronic devices are obtained through the following processes:

firstly, determining the index requirement which needs to be reached by a band-pass filter, and directly giving the following steps:

center frequency f ₀ ＝46.52MHz；

f ₀ Attenuation at + -10.0 MHz is no greater than 3.0dB;

f ₀ the in-band ripple at + -10.0 MHz is no greater than 1.0dB;

f ₀ attenuation at 16MHz is not less than 40dB;

f ₀ attenuation at + -25 MHz is not less than 60dB;

in this example, the input/output impedance is 50Ω.

Converting the requirements of the band pass filter to equivalent low pass requirements:

f ₀ ＝46.52MHz；

BW _3dB ＝10.0MHz；

BW _40dB ＝16MHz；

BW _60dB ＝25MHz；

select n=9.

The Chebyshev normalized low-pass filter with the in-band fluctuation of 0.1dB can be obtained, and parameters of the Chebyshev normalized low-pass filter are determined after table lookup.

Scaling the low pass filter to a cut-off frequency f _c =bw 3 db=10.0 MHz, the formula is as follows:

L ^* ＝L*R/ω _c ＝L*50/2πf _c ①

C ^* ＝C/ω _c ＝C/2πf _c *50 ②

and then the low pass is converted into the band pass, and the formula is as follows:

C _n ＝1/ω ₀ ² *L _n ^* ③

L _n ＝1/ω ₀ ² *C _n ^* ④

according to the table lookup and the formulas (1), (2), (3) and (4), the parameter values of each device can be obtained as follows: the first inductor L1 is 61.82nH, the first capacitor C1 is 200pF, the second inductor L2 is 504.19nH, the second capacitor C2 is 24pF, the third inductor L3 is 37.10nH, the third capacitor C3 is 330pF, the fourth inductor L4 is 554.88nH, the fourth capacitor C4 is 22pF, the fifth inductor L5 is 36.11nH, the fifth capacitor C5 is 343pF, the sixth inductor L6 is 554.88nH, the sixth capacitor C6 is 22pF, the seventh inductor L7 is 37.10nH, the seventh capacitor C7 is 330pF, the eighth inductor L8 is 504.19nH, the eighth capacitor C8 is 24pF, the ninth inductor L9 is 61.82nH, and the ninth capacitor C9 is 200pF.

The parameter values of the individual devices of the invention are thus determined.

In addition, when the Beidou intermediate frequency filter is manufactured in a trial mode, when the printed board is designed according to the requirement of the size of the B3 filter, the printed board is manufactured by using polytetrafluoroethylene plates with the thickness of 1.0 according to the characteristics of high requirement and small size of the index of the filter, and when the Beidou intermediate frequency filter is used, signals are input into the filter from the input end A, and signals meeting the requirement can be obtained from the output end B.

Claims

1. The utility model provides a medium frequency 46.52MHz band pass filter for big dipper, includes input (A), output (B) and ground connection (C), its characterized in that:

a first inductor (L1) and a first capacitor (C1) are arranged between the input end (A) and the grounding end (C) in parallel;

a second inductor (L2) is connected in series with a second capacitor (C2) between the input end (A) and the output end (B);

the output end (B) is connected with the third inductor (L3) and the third capacitor (C3) and is arranged between the output end (B) and the grounding end (C) in parallel;

the output end (B) is connected with the fourth inductor (L4) and the fourth capacitor (C4) in series, and then a fifth inductor (L5) and the fifth capacitor (C5) are connected in parallel and arranged between the output end (B) and the grounding end (C);

the output end (B) is connected with the sixth inductor (L6) and the sixth capacitor (C6) in series, and a seventh inductor (L7) and the seventh capacitor (C7) are arranged between the output end (B) and the grounding end (C) in parallel;

the output end (B) is connected with the eighth inductor (L8) and the eighth capacitor (C8) in series, and a ninth inductor (L9) and the ninth capacitor (C9) are arranged between the output end (B) and the grounding end (C) in parallel;

wherein, the liquid crystal display device comprises a liquid crystal display device,

the first inductance (L1) is 61.82nH, and the first capacitance (C1) is 200pF;

the second inductance (L2) is 504.19nH, and the second capacitance (C2) is 24pF;

the third inductance (L3) is 37.10nH, and the third capacitance (C3) is 330pF;

the fourth inductance (L4) is 554.88nH, and the fourth capacitance (C4) is 22pF;

the fifth inductance (L5) is 36.11nH and the fifth capacitance (C5) is 343pF;

the sixth inductance (L6) is 554.88nH, and the sixth capacitance (C6) is 22pF;

the seventh inductance (L7) is 37.10nH, and the seventh capacitance (C7) is 330pF;

the eighth inductor (L8) is 504.19nH, and the eighth capacitor (C8) is 24pF;

the ninth inductance (L9) is 61.82nH and the ninth capacitance (C9) is 200pF.