- #71
The Electrician
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The center frequency stays the same, but the rolloff rate is enough higher to meet your requirements. Unity remains at 10 kHz.
BiGyElLoWhAt said:So would both my lowpass filters have the same RC values?
BiGyElLoWhAt said:Yes, yes. I think I get it now. What would be a reasonable, physical approximation that I could use to get my values? I.e. how I was trying to maximize it at 10k by setting both circuits in phase with each other and they would maximize due to superposition or something along those lines, or as was mentioned early where z_1 = R_1 at 3k, etc.
BiGyElLoWhAt said:What's a reasonable threshold to call something at "unity"? I think I get what I need to do, now. Thanks.
BiGyElLoWhAt said:But that's only theoretical, right? You can't actually get the gain to be 1.
Have you determined the Q with those component values?The Electrician said:Here's the un-normalized response of your original circuit using the R and C values I gave in post #25:
I have been wanting to reconcile this equation with the plot in #25. Is there an error in this apart from the subscript?donpacino said:when analyzing the circuit, the transfer function is found seen below
Vo/Vin = [SC_2R_2 ] / [ S^2C_2^2R_2_2+S(2C_2R_2+C1R1)+1 ]
Just checked my work. Yes it is incorrect. I now got what the electrcian got. I switched some terms part way through the analysis. 1 am algebra will do that I guess.The Electrician said:donpacino in post #32 has the wrong transfer function. The pdf file in post #60 has the derivation of the correct transfer function.
My derivation is the same:
View attachment 106821
The figure of 0.33 does seem lower than what I would expect to be achievable.NascentOxygen said:With the Rs and Cs suggested, I calculate using your equation: Q = 0.333
An RC BP filter is a type of electronic circuit that is used to selectively filter out certain frequencies from a signal while allowing others to pass through. It consists of a combination of resistors (R) and capacitors (C) that work together to create a bandpass filter.
An RC BP filter works by using the properties of resistors and capacitors to create a voltage divider circuit. The resistors and capacitors are strategically placed to only allow a specific range of frequencies to pass through, while blocking out all other frequencies.
The purpose of an RC BP filter is to filter out unwanted frequencies from a signal. This can be useful in many applications, such as in audio systems to eliminate background noise or in communication systems to isolate specific frequencies.
To optimize an RC BP filter, you would need to carefully select the values of the resistors and capacitors used in the circuit. This involves calculating the cutoff frequencies and impedance values to ensure that the filter is working effectively for the desired frequency range.
Some common challenges in optimizing an RC BP filter include selecting the right combination of resistors and capacitors to achieve the desired cutoff frequencies, dealing with non-ideal components that may affect the filter's performance, and ensuring that the filter does not introduce unwanted phase shifts or distortions to the signal.