CN206422854U - Suppress the bidirectional filter circuit of low-frequency noise - Google Patents
Suppress the bidirectional filter circuit of low-frequency noise Download PDFInfo
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- CN206422854U CN206422854U CN201621330706.5U CN201621330706U CN206422854U CN 206422854 U CN206422854 U CN 206422854U CN 201621330706 U CN201621330706 U CN 201621330706U CN 206422854 U CN206422854 U CN 206422854U
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Abstract
It is high frequency high pass circuit between the common port and the front end the utility model discloses a kind of bidirectional filter circuit for suppressing low-frequency noise, including common port, front end and low frequency end, is low frequency band-pass circuit between the common port and the low frequency end.The beneficial effects of the utility model：By the way that the low pass circuit in original bidirectional filter is designed as band-pass circuit, the suppression to low-frequency noise is realized.
Description
Technical field
The utility model belongs to cable television technology field, and in particular to one kind is applied to cable television two-way light work-station
Bidirectional filter circuit.
Background technology
Currently, the bidirectional filter applied to cable television optical workstation, as shown in figure 1, by low-pass filter circuit and height
Bandpass filter circuit is constituted, and realizes the mixing or fractionation of downstream signal (high-frequency signal) and upward signal (low frequency signal).Such as meet
The 65/87MHz frequency divisions of professional standard, realize the mixing of downstream signal (87-1000MHz) and upward signal (5-65MHz)
Or split.
Low-frequency noise due to user terminal in real network is converged, and influences the transmission of upward signal, outstanding in below 25MHz
Its is serious.So in Cable TV Light station device, in addition to plug formula bidirectional filter, on radio frequency mainboard
Fixed low-frequency filter circuit is also devised with, to filter off low frequency influx noise.
Design adds the complexity of radio frequency mainboard above, and the flexibility ratio of another aspect filtering characteristic change is also deteriorated.
As devised 25MHz low-pass filter circuits on radio frequency mainboard, certain CHINA RFTCOM Co Ltd needs to dispose the light work of 20MHz LPF functions
Stand, this radio frequency mainboard cannot just be met.
Utility model content
Problem to be solved in the utility model is to provide a kind of bidirectional filter circuit for suppressing low-frequency noise.
In order to solve the above-mentioned technical problem, the utility model is adopted the following technical scheme that：Suppress the two-way filter of low-frequency noise
Ripple device circuit, including common port, front end and low frequency end, are high frequency high pass circuit between the common port and the front end,
It is low frequency band-pass circuit between the common port and the low frequency end；
Cable television downstream signal is injected from front end, and frequency division multiplexing is realized after common port and return path signal mixing,
Same transmission over coaxial cable is to user terminal；
The return path signal of user terminal passback is exported after bidirectional filter circuit separation by low frequency end.
The low frequency band-pass circuit is made up of electric capacity C1~C11, inductance L1~L7, electric capacity C1, electric capacity C2, inductance L1, electricity
Hold C3, inductance L2, electric capacity C4, inductance L3, inductance L4 to be sequentially connected in series, electric capacity C8 one end is connected between electric capacity C1, electric capacity C2
Node, other end ground connection, electric capacity C9 one end is connected to the node between inductance L1, electric capacity C3, other end ground connection, electric capacity C10 mono-
End is connected to the node between inductance L2, electric capacity C4, and the other end is grounded, and electric capacity C11 one end is connected between inductance L3, inductance L4
Node, other end ground connection, electric capacity C5, electric capacity C6, electric capacity C7 be in parallel with inductance L1, inductance L2, inductance L3 respectively, inductance L5,
Inductance L6, inductance L7 are in parallel with electric capacity C8, electric capacity C9, electric capacity C10 respectively.
The high frequency high pass circuit is made up of electric capacity C12~C22, inductance L8~L12, wherein, inductance L8~L12 with it is described
Common port and the front end are in parallel, and electric capacity C12~C17 connects with the common port and the front end.The high frequency high pass
Circuit includes including the filter capacitor of series connection, the high pass circuit on main road and LC mutual inductance circuits, the main road of the high pass circuit
Main road one end receive input signal, other end output signal output；Each two filter capacitor on the main road of the high pass circuit
Between be provided with node, the mutual inductance inductance in LC mutual inductance circuits, the LC mutual inductance circuits is connected with wherein at least one node
And Inductance and Capacitance series connection is followed by between the node and ground.
The beneficial effects of the utility model：It is real by the way that the low pass circuit in original bidirectional filter is changed to band-pass circuit
Now to the suppression of low-frequency noise.
Brief description of the drawings
Fig. 1 is the circuit theory diagrams of existing bidirectional filter circuit
Fig. 2 is the circuit theory diagrams of the utility model bidirectional filter circuit
Fig. 3 is the circuit diagram of the utility model bidirectional filter circuit one embodiment
Embodiment
As shown in Fig. 2 suppress the bidirectional filter circuit of low-frequency noise, including common port, front end and low frequency end, institute
It is high frequency high pass circuit to state between common port and the front end, is powered between the common port and the low frequency end for low-frequency band
Road.
The characteristic that the utility model bidirectional filter circuit leads to the logical low frequency resistance high frequency of high frequency resistance low frequency, inductance using electric capacity is set
Count LC filter circuits.
As shown in figure 3, the low frequency band-pass circuit is made up of electric capacity C1~C11, inductance L1~L7.The low-frequency band is powered
Routing capacitance C1~C11, inductance L1~L7 compositions, electric capacity C1, electric capacity C2, inductance L1, electric capacity C3, inductance L2, electric capacity C4, inductance
L3, inductance L4 are sequentially connected in series, and electric capacity C8 one end is connected to the node between electric capacity C1, electric capacity C2, other end ground connection, electric capacity C9 mono-
End is connected to the node between inductance L1, electric capacity C3, and the other end is grounded, and electric capacity C10 one end is connected between inductance L2, electric capacity C4
Node, other end ground connection, electric capacity C11 one end is connected to the node between inductance L3, inductance L4, other end ground connection, electric capacity C5,
Electric capacity C6, electric capacity C7 are in parallel with inductance L1, inductance L2, inductance L3 respectively, inductance L5, inductance L6, inductance L7 respectively with electric capacity C8,
Electric capacity C9, electric capacity C10 are in parallel.
The high frequency high pass circuit is made up of electric capacity C12~C22, inductance L8~L12, wherein, inductance L8~L12 with it is described
Common port and the front end are in parallel, and electric capacity C12~C17 connects with the common port and the front end.The high frequency high pass
Circuit includes including the filter capacitor of series connection, the high pass circuit on main road and LC mutual inductance circuits, the main road of the high pass circuit
Main road one end receive input signal, other end output signal output；Each two filter capacitor on the main road of the high pass circuit
Between be provided with node, the mutual inductance inductance in LC mutual inductance circuits, the LC mutual inductance circuits is connected with wherein at least one node
And Inductance and Capacitance series connection is followed by between the node and ground.
87~1000MHz cable televisions downstream signal injects from the H ends (front end) of bidirectional filter circuit, at COM ends
Frequency division multiplexing is realized after the mixing of (common port) and 25~65MHz return path signals, in same transmission over coaxial cable to user terminal；
25~65MHz return path signals that user terminal passback comes up are exported after bidirectional filter circuit separation by L ends (low frequency end).
The inserting moduleization design of bidirectional filter, adds the flexibility of optical workstation equipment filtering characteristic change.
Using the plug-in bidirectional filter module of the circuit realiration, low-frequency noise suppresses to reach more than 40dB, and pass band insertion loss is less than
1dB。
Claims (3)
1. suppress the bidirectional filter circuit of low-frequency noise, including common port, front end and low frequency end, it is characterised in that it is described
It is high frequency high pass circuit between common port and the front end, is powered between the common port and the low frequency end for low-frequency band
Road；
Cable television downstream signal injects from front end, frequency division multiplexing is realized after common port and return path signal mixing, same
Root transmission over coaxial cable is to user terminal；
The return path signal of user terminal passback is exported after bidirectional filter circuit separation by low frequency end.
2. suppress the bidirectional filter circuit of low-frequency noise according to claim 1, it is characterised in that the low-frequency band is powered
Routing capacitance C1~C11, inductance L1~L7 compositions, electric capacity C1, electric capacity C2, inductance L1, electric capacity C3, inductance L2, electric capacity C4, inductance
L3, inductance L4 are sequentially connected in series, and electric capacity C8 one end is connected to the node between electric capacity C1, electric capacity C2, other end ground connection, electric capacity C9 mono-
End is connected to the node between inductance L1, electric capacity C3, and the other end is grounded, and electric capacity C10 one end is connected between inductance L2, electric capacity C4
Node, other end ground connection, electric capacity C11 one end is connected to the node between inductance L3, inductance L4, other end ground connection, electric capacity C5,
Electric capacity C6, electric capacity C7 are in parallel with inductance L1, inductance L2, inductance L3 respectively, inductance L5, inductance L6, inductance L7 respectively with electric capacity C8,
Electric capacity C9, electric capacity C10 are in parallel.
3. suppress the bidirectional filter circuit of low-frequency noise according to claim 1, it is characterised in that the high frequency height is powered
Road includes including the filter capacitor of series connection on main road and LC mutual inductance circuits, the main road of the high pass circuit, the high pass circuit
Main road one end receives input signal, other end output signal output；On the main road of the high pass circuit each two filter capacitor it
Between be provided with node, the mutual inductance inductance that is connected with wherein at least one node in LC mutual inductance circuits, the LC mutual inductance circuits and
Inductance and Capacitance series connection is followed by between the node and ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621330706.5U CN206422854U (en) | 2016-12-06 | 2016-12-06 | Suppress the bidirectional filter circuit of low-frequency noise |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621330706.5U CN206422854U (en) | 2016-12-06 | 2016-12-06 | Suppress the bidirectional filter circuit of low-frequency noise |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206422854U true CN206422854U (en) | 2017-08-18 |
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ID=59575199
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621330706.5U Expired - Fee Related CN206422854U (en) | 2016-12-06 | 2016-12-06 | Suppress the bidirectional filter circuit of low-frequency noise |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN206422854U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111022276A (en) * | 2019-12-27 | 2020-04-17 | 哈尔滨工业大学 | Hall effect thruster low-frequency oscillation suppression outer loop |
-
2016
- 2016-12-06 CN CN201621330706.5U patent/CN206422854U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111022276A (en) * | 2019-12-27 | 2020-04-17 | 哈尔滨工业大学 | Hall effect thruster low-frequency oscillation suppression outer loop |
| CN111022276B (en) * | 2019-12-27 | 2021-03-12 | 哈尔滨工业大学 | Hall effect thruster low-frequency oscillation suppression outer loop |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170818 Termination date: 20191206 |