w****a 发帖数: 11 | 1 作了一个简单的放大器准备做实验用,结果发现即使没有接任何输入的时候,放大器输
出有噪音(图1),加上信号后输出如图2 所示。
请问大家有没有什么办法把图2中的放大器噪声信号去掉。 已经试过Savitzky-Golay
filter, 感觉不是很理想。
谢谢! |
r*****e 发帖数: 620 | 2 首先要确定noise来自源信号 还是放大器自身 或者是scope
看了这两张图我觉得noise是测试设备造成的
你用的是coaxial cable么,或者active probe?
如果probe的signal和ground在测试点相距比较远的话可能会引入噪声,或者可以加一
个metal shield box试试看
【在 w****a 的大作中提到】 : 作了一个简单的放大器准备做实验用,结果发现即使没有接任何输入的时候,放大器输 : 出有噪音(图1),加上信号后输出如图2 所示。 : 请问大家有没有什么办法把图2中的放大器噪声信号去掉。 已经试过Savitzky-Golay : filter, 感觉不是很理想。 : 谢谢!
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w****a 发帖数: 11 | 3 用的是coaxial cable,不是active probe。现在觉得放大器的可能性更大,我重新作
了一个,基本一样表现。明天放到盒子里看看。
谢谢! |
s*******y 发帖数: 4173 | 4 你的电源是那种的啦,
还有看你放大器的结构啦,放大器本身也是有噪声的。 |
W***n 发帖数: 11530 | 5
If the 2nd pic is your signal, you seem to have a problem. You might have a
bad grounding. What is the vertical scale in the graph?
【在 w****a 的大作中提到】 : 作了一个简单的放大器准备做实验用,结果发现即使没有接任何输入的时候,放大器输 : 出有噪音(图1),加上信号后输出如图2 所示。 : 请问大家有没有什么办法把图2中的放大器噪声信号去掉。 已经试过Savitzky-Golay : filter, 感觉不是很理想。 : 谢谢!
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w****a 发帖数: 11 | 6 5mv/div
I checked all the groundings and they are well connected. Any more
suggestion?
a
【在 W***n 的大作中提到】 : : If the 2nd pic is your signal, you seem to have a problem. You might have a : bad grounding. What is the vertical scale in the graph?
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s*******y 发帖数: 4173 | 7 what kind of power supply do you use?
switching power supply?
【在 w****a 的大作中提到】 : 5mv/div : I checked all the groundings and they are well connected. Any more : suggestion? : : a
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z*****n 发帖数: 7639 | 8 I also doubt this is the problem.
【在 s*******y 的大作中提到】 : what kind of power supply do you use? : switching power supply?
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W***n 发帖数: 11530 | 9
Without your ckt diagram, can't tell. Did you choose the right value for
decoupling cap?
Btw, what's the horizontal scale?
【在 w****a 的大作中提到】 : 5mv/div : I checked all the groundings and they are well connected. Any more : suggestion? : : a
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a****c 发帖数: 46 | |
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b*****e 发帖数: 1193 | |
w****a 发帖数: 11 | 12 先谢谢大家!
The horizontal scale is 50ns/div. I'm using TI OPA656NB, the decoupling
caps are 6.8uF, 0.1uF and 200pF. Circuit is very simple, just the OpAmp and
decoupling caps and feedback resistor.
【在 W***n 的大作中提到】 : : Without your ckt diagram, can't tell. Did you choose the right value for : decoupling cap? : Btw, what's the horizontal scale?
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s*******y 发帖数: 4173 | 13 resistor value?
resistor will also generate thermal noise.
and
【在 w****a 的大作中提到】 : 先谢谢大家! : The horizontal scale is 50ns/div. I'm using TI OPA656NB, the decoupling : caps are 6.8uF, 0.1uF and 200pF. Circuit is very simple, just the OpAmp and : decoupling caps and feedback resistor.
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S********5 发帖数: 1058 | |
w****a 发帖数: 11 | 15 Power supply is HP 6624a DC power supply. Is that a problem?
The circuit is attached below.
【在 s*******y 的大作中提到】 : what kind of power supply do you use? : switching power supply?
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s*******y 发帖数: 4173 | 16 纹波和噪声 500μV
for this type of power supply, |
w****a 发帖数: 11 | 17 Any suggestion to eliminate or reduce the noise? thanks!
【在 s*******y 的大作中提到】 : 纹波和噪声 500μV : for this type of power supply,
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le 发帖数: 190 | 18 have you tried dry battery to replace the power supply
【在 w****a 的大作中提到】 : Any suggestion to eliminate or reduce the noise? thanks!
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i******n 发帖数: 15 | 19 use differential opamp instead of sigle end |
s*******y 发帖数: 4173 | 20 if possible, consider the differential input.
which can eliminate power supply noise.
【在 w****a 的大作中提到】 : Any suggestion to eliminate or reduce the noise? thanks!
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s*******y 发帖数: 4173 | 21 if possible, consider the differential input.
【在 w****a 的大作中提到】 : Any suggestion to eliminate or reduce the noise? thanks!
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d********g 发帖数: 11948 | 22 boost your PSR... possibly your vdd source is noisy... try check it or your
cable may caused some. how much inductance is your cable? |