designing a bandpass loww freq. filter

passive loww pass filter

how can i design (or buy) band pass filters with :
F0 (kHz) : 37.879
53.674
48.363
68.677
63.981
79.976
91.146
75.000
106.250
90.000
112.500


bandwidths =1 khz approximately. so that not overlap other bandin neighbor .
Q is ery important(> 100).
Filter bank is better.

another BP filters needed are :

f0 (Hz): 60.317
85.061
60.004
84.997
60.020
75.025
85.024
60.000
85.000
60.000
75.000

max 3-dB BW=10 Hz.
thnks alot.

Hi,

Designing bandpass filter is not that difficult. But I have a question here. Are all that center frequencies. So, do you need all seperate filters?

Design:
1) First, get the substrate information: height and dielectric constant
2) Design a low pass filter. Use frequency transformation and also find order of the filter from attenuation characterstics. You can design chebyshev response with -3 db ripple or -0.5 db ripple
3) Transform low pass filter in to bandpass filter using filter transformation formula
4) Simulate lumped element design in ansoft designer or awr microwave office
6) Do, the tuning procedure to get the proper ripples and response.
7) Q of greater than 100 seams to me impractical. Because in practice, you have parasitics formed in your circuit, so you get a lot of resistance and that will lower the Q.

Thanks

The frequency is low.
It sounds to me that your BPF design is used in ADSL / VDSL.
Right?
You can reference to some filter design book.

Thank you,

but the problem is practical and i need filter components (like Kr Filters Co. products).
which components did you know for that?
if it is a tunable filter bank?

thanks.

A lot of specification details are missing. Giving a center frequency, a bandwidth and a "Q" value isn't a filter specification. Particularly a stopband specification would be needed. At present, any filter starting with 2nd order may fit. Also the intended filter type (active, passive, SC), accuracy and dynamic range should be known.