R
Rob Gaddi
Guest
So I need to do some wideband low RF filtering (flat to 0.5 dB from
40-100 MHz, fairly sharp cut off on the high end, low end can cut off or
not as convenient), and have found that my lossless LC ladders are in
fact anything but. Who knew that several ohms of resistance in my 0603
inductors would add up, other of course than anyone who had stopped to
think about it.
I've managed to massage the filters back into shape through trial and
error in RFSim99, but in the process have beaten my nice little
Butterworth and Chebyshev filters into unrecognizable scattered heaps of
very sore poles, making irrelevant decades of filter theory. It strikes
me that there must have been an easier way of doing it.
So, for future reference, how should one go about doing wideband RF
filtering? I've got books here with plenty of suggestions if I felt
like blowing ten thousand dollars designing an analog ASIC, but I'd like
a solution with a few less zeros, not to mention not having to learn
analog ASIC design.
-- Rob
40-100 MHz, fairly sharp cut off on the high end, low end can cut off or
not as convenient), and have found that my lossless LC ladders are in
fact anything but. Who knew that several ohms of resistance in my 0603
inductors would add up, other of course than anyone who had stopped to
think about it.
I've managed to massage the filters back into shape through trial and
error in RFSim99, but in the process have beaten my nice little
Butterworth and Chebyshev filters into unrecognizable scattered heaps of
very sore poles, making irrelevant decades of filter theory. It strikes
me that there must have been an easier way of doing it.
So, for future reference, how should one go about doing wideband RF
filtering? I've got books here with plenty of suggestions if I felt
like blowing ten thousand dollars designing an analog ASIC, but I'd like
a solution with a few less zeros, not to mention not having to learn
analog ASIC design.
-- Rob