CN1787366A - High pass filting circuit - Google Patents
High pass filting circuit Download PDFInfo
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- CN1787366A CN1787366A CN 200410077486 CN200410077486A CN1787366A CN 1787366 A CN1787366 A CN 1787366A CN 200410077486 CN200410077486 CN 200410077486 CN 200410077486 A CN200410077486 A CN 200410077486A CN 1787366 A CN1787366 A CN 1787366A
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- pass filtering
- filtering circuit
- frequency
- signal
- circuit
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Abstract
This invention relates to a high pass filtering circuit including a capacitor and a resistor, in which, said capacitor is serial to the input end of said high pass filtering circuit, said resistor is parallel to the output of said filtering circuit and one end of said capacitor is connected with said resistor. Said circuit is used in the computer mainboard circuit to control the pass of low frequency signals.
Description
[technical field]
The invention relates to a kind of high-pass filtering circuit, particularly a kind of high-pass filtering circuit that can effectively suppress low frequency signal.
[background technology]
Along with developing rapidly of electronic technology, modern electronic equipment has been widely used in human lives's every field.Current, electronic equipment has been in the period of develop rapidly, and the extensive use of electronic equipment and development cause constantly increasing at the electromagnetic field that its surrounding space produces.Industry is mainly taked three measures in anti-electromagnetic interference, i.e. shielding, filtering and ground connection.But simple employing shielding can not provide complete electromagnetic interference shielding, because the cable in equipment or the system is only the most effective interference reception and transmitting antenna.Usually the measure of taking is to add filter circuit, to cut off the path of electromagnetic interference along holding wire or power line propagation, with the perfect electromagnetic interference shielding of the common formation of shielding.
Please refer to Fig. 1, a kind of high-pass filtering circuit 10, it comprises a filter capacitor 11, and an end of this filter capacitor 11 links to each other with signal input part, and the other end is connected to signal output part.Filter capacitor 11 has the electrical characteristics of logical high frequency, resistance low frequency, can effectively stop the signal of low frequency to flow into signal output part from signal input part.This high-pass filtering circuit 10 is used in usually in the less demanding device of signal integrity.But the defective of this high-pass filtering circuit 10 is that the signal of determining which kind of frequency can need constantly to change described filter capacitor 11 by behind this filter capacitor 11, makes it can effectively suppress passing through of low frequency signal.
Please refer to Fig. 2, other has a kind of high-pass filtering circuit 20, and it comprises one first electric capacity 22, one second electric capacity 24 and an inductance 26.This first electric capacity 22 is connected between the signal input part, and this inductance 26 is connected on signal input part, and the one end links to each other with first electric capacity 22.This second electric capacity 24 is connected between the signal output part, and the other end of this inductance 26 links to each other with this second electric capacity 24.This high-pass filtering circuit 20 can filter low-frequency interference signal, and can determine accurately that the signal of which kind of frequency can pass through this inductance 26, arriving signal output.But it is many that the defective of this kind high-pass filtering circuit 20 is to form electronic component, and shared space is big, and cost is higher.
[summary of the invention]
The object of the present invention is to provide a kind of high-pass filtering circuit, particularly a kind of simple in structure, high-pass filtering circuit that can effectively suppress low frequency signal.
The objective of the invention is to realize by following scheme: a kind of high-pass filtering circuit of the present invention comprises electric capacity and a resistance; Described capacitance series is in the input of described high-pass filtering circuit, and described resistance is parallel to the output of described high-pass filtering circuit, and an end of described electric capacity is connected with described resistance.
The invention has the advantages that: high-pass filtering circuit of the present invention comprises electric capacity and a resistance, and it is simple in structure, and can suppress low frequency signal effectively.
[description of drawings]
Fig. 1 is the circuit diagram of known high-pass filtering circuit.
Fig. 2 is the circuit diagram of known another kind of high-pass filtering circuit.
Fig. 3 is the circuit diagram of high-pass filtering circuit of the present invention.
Fig. 4 is the amplitude-frequency characteristic oscillogram of high-pass filtering circuit of the present invention.
[embodiment]
See also Fig. 3, a kind of high-pass filtering circuit 30 of the present invention comprises electric capacity 32 and a resistance 34.Described electric capacity 32 is serially connected with signal input part, and described resistance 34 is parallel to signal output part, and an end of described electric capacity 32 links to each other with described resistance 34.
See also Fig. 4, the amplitude-frequency characteristic oscillogram of high-pass filtering circuit 30 of the present invention, it is arranged in a reference axis 50.Transverse axis 52 representatives of described reference axis 50 are by the frequency of described high-pass filtering circuit 30, and its longitudinal axis 54 representatives are by the amplitude of the frequency of described high-pass filtering circuit 30.On described transverse axis 52 toggle frequency is arranged, it uses f
0Expression.In the amplitude-frequency characteristic waveform 40 of described high-pass filtering circuit 30, described toggle frequency f
0The left side be first curve 42 of steep rising, described toggle frequency f
0The right be the second comparatively level and smooth curve 44.The frequency signal of these first curve, 42 pairing transverse axis 52 can not pass through described high-pass filtering circuit 30, and promptly frequency is less than toggle frequency f
0Signal suppressed by described high-pass filtering circuit 30.The frequency signal of described second curve, 44 pairing transverse axis 52 can pass through described high-pass filtering circuit 30, and promptly frequency is greater than toggle frequency f
0Signal be not subjected to the influence of described high-pass filtering circuit 30.
Described toggle frequency f
0Computing formula be:
f
0＝1/(2πτ)＝1/(2πR1C1)
At aforementioned calculation toggle frequency f
0Formula in, π represents constant, C1 represents the appearance value of described electric capacity 32, R1 represents the resistance of described resistance 34.
Usually in the motherboard circuit of computer,, all be high-frequency signal and make clock signal, data-signal and the control signal of motherboard circuit operate as normal because most of noises and interference signal all are low frequency signals.Then the noise of these low frequencies and interference signal are to suppress or to make it to decay by described high-pass filtering circuit 30, and the clock signal of these high frequencies, data-signal and control signal need not change by described high-pass filtering circuit 30.Then in the motherboard circuit design, use a testing equipment to measure the noise of designed circuit medium and low frequency and the frequency separation that interference signal is mainly concentrated.Calculate the value of lowest signal frequency in clock signal, data-signal and the control signal.Be higher than the frequency separation place that described noise and interference signal are mainly concentrated being lower than described lowest signal frequency values, select a frequency, this frequency is described toggle frequency f
0By above-mentioned toggle frequency f
0Computing formula determine the appearance value of described electric capacity 32 and the resistance of described resistance 34, promptly 2 times inverse of constant π, described electric capacity 32 appearance values, described resistance 34 resistance products equals described toggle frequency f
0
In the motherboard circuit, use described high-pass filtering circuit 30, can determine described toggle frequency f exactly
0, reduce or lower noise and interference signal to greatest extent.At definite toggle frequency f
0Afterwards, by toggle frequency f
0Computing formula can easily determine the appearance value of described electric capacity 32, the resistance of described resistance 34.
Above-mentioned high-pass filtering circuit 30 also can be used in the circuit of other devices, suppresses passing through of low-frequency disturbance and noise signal effectively.
Claims (6)
1. a high-pass filtering circuit comprises electric capacity and a resistance;
It is characterized in that: described capacitance series is in the input of described high-pass filtering circuit, and described resistance is parallel to the output of described high-pass filtering circuit, and an end of described electric capacity is connected with described resistance.
2. high-pass filtering circuit as claimed in claim 1 is characterized in that: the amplitude-frequency characteristic waveform of described high-pass filtering circuit comprises second curve that first curve and of a steep rising is comparatively level and smooth.
3. high-pass filtering circuit as claimed in claim 2 is characterized in that: the frequency that first curve of described high-pass filtering circuit is corresponding with the second curve intersection place is the toggle frequency of described high-pass filtering circuit.
4. high-pass filtering circuit as claimed in claim 3 is characterized in that: described toggle frequency is not need the minimum frequency that suppresses by described high-pass filtering circuit.
5. high-pass filtering circuit as claimed in claim 4 is characterized in that: the value of described toggle frequency equals 2 times inverse of constant π, described capacitor's capacity, described resistance product.
6. high-pass filtering circuit as claimed in claim 5 is characterized in that: described high-pass filtering circuit applies in the computer motherboard circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410077486 CN1787366A (en) | 2004-12-11 | 2004-12-11 | High pass filting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410077486 CN1787366A (en) | 2004-12-11 | 2004-12-11 | High pass filting circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1787366A true CN1787366A (en) | 2006-06-14 |
Family
ID=36784713
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200410077486 Pending CN1787366A (en) | 2004-12-11 | 2004-12-11 | High pass filting circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1787366A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103813055A (en) * | 2013-12-27 | 2014-05-21 | 宇龙计算机通信科技(深圳)有限公司 | Lock oscillating circuit and video unit |
-
2004
- 2004-12-11 CN CN 200410077486 patent/CN1787366A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103813055A (en) * | 2013-12-27 | 2014-05-21 | 宇龙计算机通信科技(深圳)有限公司 | Lock oscillating circuit and video unit |
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|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |