CN211791459U

CN211791459U - MOCA filter

Info

Publication number: CN211791459U
Application number: CN202020684755.9U
Authority: CN
Inventors: 陈棒棒
Original assignee: CIG Shanghai Co Ltd
Current assignee: CIG Shanghai Co Ltd
Priority date: 2020-04-28
Filing date: 2020-04-28
Publication date: 2020-10-27
Anticipated expiration: 2030-04-28

Abstract

The utility model discloses a MOCA wave filter, including first terminal and second terminal, its characterized in that, MOCA wave filter still includes high pass filter and low pass filter between first terminal and the second terminal, high pass filter is including establishing ties electric capacity and resonant circuit in proper order, low pass filter includes electric capacity and resonant circuit that connect in parallel each other. Experiments prove that the MOCA filter is small in size, has insertion loss of about 4dB, and has good out-of-band rejection degree and good in-band flatness.

Description

MOCA filter

Technical Field

The utility model relates to a wave filter, in particular to MOCA wave filter.

Background

The filter is widely applied to high-frequency electronic circuits and can be divided into a low-pass filter, a high-pass filter and a band-pass filter, the low-pass filter and the high-pass filter can form an MOCA filter, signals of a certain section of frequency can be selected to pass through a circuit, signals of other frequencies are blocked or greatly attenuated, the MOCA filter has no signal gain and also has certain signal loss, and the loss of the passing signals and the suppression degree of out-of-band signals are two main parameters of the filter.

The MOCA technology is a technical scheme for solving the problem of using a home network by using an existing Coaxial cable in a home, is called a Coaxial ethernet system, and is a solution for realizing bidirectional data transmission based on an existing Coaxial cable distribution network and realizing bidirectional network improvement for an HFC (Hybrid Fiber-coax network) network, which is specially designed for cable television network operators. The television and the bidirectional data signals are transmitted on the same coaxial cable, the bidirectional transformation of the HFC network is greatly simplified, and the existing broadcasting HFC network is utilized to provide digital television, interactive television and broadband service for users. The MOCA filter is a filter that is custom-tuned to the frequency Band of MOCA, and the frequency Band of the filter is High Band: 1475-1675 MHz. Most of the MOCA filters on the market have higher cost and larger volume.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide a MOCA filter in order to overcome among the prior art MOCA filter most all defect with higher costs, the volume is small enough.

The utility model discloses a solve above-mentioned technical problem through following technical scheme:

a MOCA filter comprising a first terminal and a second terminal, characterized in that the MOCA filter further comprises a high pass filter and a low pass filter between the first terminal and the second terminal, wherein,

the high-pass filter comprises a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and a fifth capacitor which are sequentially connected in series, a first resonant circuit between the first capacitor and the second capacitor, a second resonant circuit between the second capacitor and the third capacitor, a third resonant circuit between the third capacitor and the fourth capacitor and a fourth resonant circuit between the fourth capacitor and the fifth capacitor,

the low-pass filter comprises a sixth capacitor, a seventh capacitor and an eighth capacitor which are connected in parallel with each other, a fifth resonant circuit between the sixth capacitor and the seventh capacitor, and a sixth resonant circuit between the seventh capacitor and the eighth capacitor,

the first terminal is connected with one end of the first capacitor, the other end of the first capacitor is connected with the first resonance circuit and the second capacitor, one end of the fifth capacitor is connected with the fourth capacitor and the fourth resonance circuit, the other end of the fifth capacitor is connected with the sixth capacitor and the fifth resonance circuit, and the second terminal is connected with the eighth capacitor and the sixth resonance circuit.

Preferably, the first, second, third and fourth resonant circuits each comprise an inductance and a capacitance in series.

Preferably, the fifth resonant circuit and the sixth resonant circuit comprise an inductance and a capacitance in parallel.

Preferably, the MOCA filter has an order of 6 to 10.

Preferably, the MOCA filter is disposed in a four-layer PCB (printed circuit board) including a top layer, a bottom layer, and a ground layer and a power layer between the top layer and the bottom layer, wherein the MOCA filter is disposed on the bottom layer.

Preferably, the frequency band of the MOCA filter is 1475-1675 MHz.

On the basis of the common knowledge in the field, the above preferred conditions can be combined at will to obtain the preferred embodiments of the present invention.

The utility model discloses an actively advance the effect and lie in: the whole MOCA filter is built by a high-pass filter and a low-pass filter, the first resonant circuit to the fourth resonant circuit are four wave traps, the four wave traps and a capacitor connected in series are jointly superposed to form the high-pass filter with good sideband suppression degree, the fifth resonant circuit and the sixth resonant circuit are two wave traps, and the fifth resonant circuit and the sixth resonant circuit and the capacitor connected in parallel are jointly superposed to form the low-pass filter with good sideband suppression degree. Experiments prove that the MOCA filter is small in size, the occupied area of the PCB body can be 66 x 21mm, and better balance between an out-of-band suppression degree and insertion loss can be realized.

Drawings

Fig. 1 is an equivalent circuit diagram of an MOCA filter according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of performance parameters (return loss and gain) of an MOCA filter according to an embodiment of the present invention.

Description of the reference numerals

P1, P2 first terminal, second terminal

C1, C2, C3, C4 and C5 first capacitor, second capacitor, third capacitor, fourth capacitor and fifth capacitor

C12, C13, C14 sixth capacitor, seventh capacitor and eighth capacitor

11. 12, 13, 14 first resonant circuit, second resonant circuit, third resonant circuit, fourth resonant circuit

15. 16 fifth and sixth resonance circuits

Detailed Description

The present invention is further illustrated by way of the following examples, which are not intended to limit the scope of the invention.

Referring to fig. 1 to 2, the MOCA filter according to the present embodiment includes a first terminal P1 and a second terminal P2, and a high pass filter and a low pass filter between the first terminal P1 and the second terminal P2, wherein,

the high-pass filter comprises a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5 which are sequentially connected in series, a first resonant circuit 11 between the first capacitor C1 and the second capacitor C2, a second resonant circuit 12 between the second capacitor C2 and the third capacitor C3, a third resonant circuit 13 between the third capacitor C3 and the fourth capacitor C4 and a fourth resonant circuit 14 between the fourth capacitor C4 and the fifth capacitor C5,

the low pass filter comprises a sixth capacitor C12, a seventh capacitor C13 and an eighth capacitor C14 connected in parallel with each other, a fifth resonant circuit 15 between the sixth capacitor C12 and the seventh capacitor C13, and a sixth resonant circuit 16 between the seventh capacitor C13 and the eighth capacitor C14,

a first terminal P1 is connected to one end of a first capacitor C1, the other end of the first capacitor C1 is connected to the first resonant circuit 11 and the second capacitor C2, one end of a fifth capacitor C5 is connected to the fourth capacitor C4 and the fourth resonant circuit 14, the other end of the fifth capacitor C5 is connected to the sixth capacitor C12 and the fifth resonant circuit 15, and a second terminal P2 is connected to the eighth capacitor C14 and the sixth resonant circuit 16.

Specifically, the first resonant circuit includes an inductor L1 and a capacitor C8 connected in series, the second similar resonant circuit includes an inductor L2 and a capacitor C9 connected in series, the third resonant circuit includes an inductor L3 and a capacitor C10 connected in series, and the fourth resonant circuit includes an inductor L4 and a capacitor C11 connected in series. The first resonant circuit to the fourth resonant circuit are four wave traps, and a high-pass filter with good sideband suppression degree is superposed with the capacitors connected in series.

The fifth resonant circuit comprises an inductor L5 and a capacitor C6 in parallel, and the sixth resonant circuit comprises an inductor L6 and a capacitor C7 in parallel. The fifth resonance circuit and the sixth resonance circuit are two wave traps, and a low-pass filter with good sideband suppression degree is superposed with the parallel capacitors.

The MOCA filter is disposed in a four-Layer PCB including a TOP Layer (Layer1- - -TOP), a bottom Layer (Layer4- - -BOT), and a ground Layer (Layer2- - -GND) and a power Layer (Layer3- - -VCC) between the TOP Layer and the bottom Layer, wherein the MOCA filter is disposed on the bottom Layer. The MOCA filter may also be referred to as a PCB MOCA filter, and in this embodiment, the PCB MOCA filter uses stack information as shown in the table below, with the components at the L4 level and referenced at the L2 level. The radio frequency line impedance is controlled to 75 ohms.

Referring to fig. 2, the operating bandwidth, insertion loss, and out-of-band rejection of the MOCA filter were tested, and the test results are shown in the screenshot of the network analyzer. The operating bandwidth BW represents the operating band selection from the first terminal P1 to the second terminal P2 in HZ; the first resonant circuit to the sixth resonant circuit are all wave traps, and the calculation formula of the wave trap is f ═ 1/(2 pi) √ LC, wherein L and C represent inductance and capacitance values in the wave trap, and f is the band stop frequency of the wave trap; the insertion loss IL represents the energy loss from the first terminal P1 to the second terminal P2 in dB, and the calculation formula is IL-10 × log (P1/P2), where P1 in the formula is the input power of the first terminal P1 and P2 in the formula is the output power of the second terminal P2 and m w; in addition, if the out-of-band rejection degree of the filter is to be improved, the order of the filter may be increased, and the increase of the order inevitably causes the increase of the insertion loss, so a compromise scheme is required to be made according to the actual usage scenario requirements. According to experiments, the order of the MOCA filter is selected to be 6-10.

The insertion loss IL test data of the filter is shown as Mark4 to Mark5 (insertion loss of 4.12 and 4.11dB, respectively) at S21 in fig. 2, and the data of the out-of-band suppression degree is shown as Mark1 and Mark2 (45.51 dB and 44.14dB, respectively) at S21 in fig. 2, where the abscissa represents frequency in HZ, the S11 and S22 ordinate represent return loss in dB, and the S12 and S21 ordinate represent transmission coefficient, i.e., gain, in dB.

The MOCA filter is used for production projects in small batches, has insertion loss of about 4dB, good out-of-band rejection degree and good in-band flatness, and therefore can bring economic value for replacing an integrated filter.

Although particular embodiments of the present invention have been described above, it will be appreciated by those skilled in the art that these are examples only and that the scope of the present invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and the principles of the present invention, and these changes and modifications are all within the scope of the present invention.

Claims

1. A MOCA filter comprising a first terminal and a second terminal, characterized in that the MOCA filter further comprises a high pass filter and a low pass filter between the first terminal and the second terminal, wherein,

2. The MOCA filter of claim 1, wherein the first resonant circuit, the second resonant circuit, the third resonant circuit, and the fourth resonant circuit each comprise an inductor and a capacitor in series.

3. The MOCA filter of claim 1, wherein the fifth resonant circuit and the sixth resonant circuit comprise an inductor and a capacitor in parallel.

4. The MOCA filter of any of claims 1-3, wherein the MOCA filter is of order 6 to 10.

5. The MOCA filter of any of claims 1-3, wherein the MOCA filter is disposed in a four-layer PCB, the PCB including a top layer, a bottom layer, and a ground layer and a power layer between the top layer and the bottom layer, wherein the MOCA filter is disposed on the bottom layer.

6. The MOCA filter of any of claims 1-3, wherein the frequency band of the MOCA filter is 1475-1675 MHz.