I'm needing to design a somewhat narrow band pass filter for a project. I'm new to audio circuit design, but I do have a [basic] understanding of electronics. I've done some research on different types of filters, and I'm hoping someone can point me in the right direction of which type of filter I need and perhaps provide some design insights.
Here are the specifications:
- audio line level input (-10)
- pass between 165 Hz and 255 Hz frequencies
- very sharp frequency cutoffs, but I don't mind heavy attenuation of the edges of the frequency range defined above
- audio line level output (-10)
I don't mind building a 4th or more ordered circuit; I just figured the community out there may have a more efficient way of doing things for a 100 Hz band filter? Any tips or ideas would be greatly appreciated.
Here are the specifications:
- audio line level input (-10)
- pass between 165 Hz and 255 Hz frequencies
- very sharp frequency cutoffs, but I don't mind heavy attenuation of the edges of the frequency range defined above
- audio line level output (-10)
I don't mind building a 4th or more ordered circuit; I just figured the community out there may have a more efficient way of doing things for a 100 Hz band filter? Any tips or ideas would be greatly appreciated.
Since this is a line level filter there's no reason not to go with an active filter. You could try TI's Filterpro Desktop:- Active Filter Design Application - FILTERPRO - TI Software Folder
You can generate a number of filters pretty quickly using this software, it will show you the number of stages required for different stopband attenuations, the min. GBW of the opamps and you will get some idea of the tradeoffs involved in different types of filters and what is achievable in practise.
w
You can generate a number of filters pretty quickly using this software, it will show you the number of stages required for different stopband attenuations, the min. GBW of the opamps and you will get some idea of the tradeoffs involved in different types of filters and what is achievable in practise.
w
Yay! Software!
Excellent! I'll try out the software - that will take a lot of guessing out of designing the circuit. Outside of that, I would need to use the equations to make a "best guess" of the component ratings I need. Actually simulating the setup will be much easier. Thanks!
Excellent! I'll try out the software - that will take a lot of guessing out of designing the circuit. Outside of that, I would need to use the equations to make a "best guess" of the component ratings I need. Actually simulating the setup will be much easier. Thanks!
Yes - I've considered rummaging through DigiKey to see what they might have. I may still do that. 🙂
OK - I've designed several candidate circuits using the TI software, and I've constructed one of them using a TL074 quad op-amp chip I had on hand, but it doesn't seem to perform like I expected. I put together a simple frequency generator (don't ask), and got a fair filtering response, but when I tried another input (using a powered electret condenser mic at a lower voltage), I could not detect any filtering going on at all. This has posed two questions for me:
1. Can anyone recommend to me an op-amp chip that would work best for my needs?
2. Will the filter's response ability be affected by the input signal strength (sort of like using a compressor or limiter)?
Any help would be appreciated!
1. Can anyone recommend to me an op-amp chip that would work best for my needs?
2. Will the filter's response ability be affected by the input signal strength (sort of like using a compressor or limiter)?
Any help would be appreciated!
- Status
- Not open for further replies.