Help me check a low-pass filter design for Radio Telescope project

[Buck12]

I am working on a designing a Radio Telescope for a school UROP and I need help designing a low-pass filter for a section of this project. I need a cutoff frequency of ~ 1 MHz (determined thus far) and I was planning on designing a passive Bessel low-pass filter. My questions basically is, for the application specified, is this a reasonable plan? Would an active filter be better?

Thank you

 

[KJ6EAD]

Re: Analog Filter Design

It depends on how sharp the cutoff needs to be and how much passband attenuation you're willing to accept. If you have plenty of signal and don't need a sharp cutoff, passive will work, otherwise active.

 

[LvW]

Re: Analog Filter Design

It depends on how sharp the cutoff needs to be and how much passband attenuation you're willing to accept. If you have plenty of signal and don't need a sharp cutoff, passive will work, otherwise active.

I think, the decision between active and passive is a bit more sophisticated. Both alternatives are, of course, possible and a choice depends on gain/damping requirements, transfer function order, power requirements/availability, technological aspects (IC yes/no?), and other operational/economical requirements.

 

[Buck12]

Re: Analog Filter Design

I think, the decision between active and passive is a bit more sophisticated. Both alternatives are, of course, possible and a choice depends on gain/damping requirements, transfer function order, power requirements/availability, technological aspects (IC yes/no?), and other operational/economical requirements.

To be honest I have not learned a whole lot about Active filters yet (am currently enrolled in a class that will cover it later this spring), but I plan on teaching myself what I need to know. As far as what you have stated, I will have to look into these concerns and get back to you with more information.

Thanks for the speedy reply guys,

 

[LvW]

Re: Analog Filter Design

OK, that`s a good approach. A good decision needs a broad range of requirements/specifications.