Can anyone help me identify why my data for a bandpass filter does not match the theory curve?

Question

Lee 2016-10-30

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/309880-can-anyone-help-me-identify-why-my-data-for-a-bandpass-filter-does-not-match-the-theory-curve

关闭： MATLAB Answer Bot 2021-8-20

I had my data checked by my professor before we left the lab. It was the expected plot from what he said. It's the phase diagram for my Bandpass filter using 2 capacitors. For reference, this is how it should look. http://www.electronics-tutorials.ws/filter/filter_7.html .

Im not sure why our and/or how our dat is shifted and simple transforms of the data don't seem to work.

3 个评论
显示 1更早的评论隐藏 1更早的评论

Lee 2016-10-30

The transfer function is definitely the expected one. I'm 100% certain of that. We get our data from an ELVIS board using National Instrument's Software and then import the data to Matlab. I think the data is correct. I think that it's the way labview chooses to express the data. If my assumption is correct, there should be something with the way the phase is displayed that I can transform it to fit my data. I think i'm just missing whatever that is.

Star Strider 2016-10-31

Without your code and your data it’s difficult to determine what the problem may be (assuming I could do it then). It looks to me that there’s an unaccounted-for series capacitance that is producing a significant phase lead in your data.

That’s the best I can do.

此问题已关闭。

Answer 1

cool 2016-12-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/309880-can-anyone-help-me-identify-why-my-data-for-a-bandpass-filter-does-not-match-the-theory-curve#answer_247403

how did you get the data of different frequencies? by sweep frequency (eg. 1Hz to 100Hz, 10Hz/s variation)? the filter has some delay, if you variation is too fast, maybe the data you get is not correct. you can do some fix frequecy test, sample data when the output is stable. all the components you use may not precise enough.