I would like to make a low pass filter with a corner frequency of approx. 200MHz which uses a variable capacitor (range 100pF to 2000pF). All I have seen so far are Butterworth or Chebyshev filters with fixed capacitors, but when I look up simple low pass filters I see two component filters. (NOTE: The filter will follow a buffer amplifier, accuracy is not vital because all I will be doing is using a diode detector to roughly determine the value of the variable capacitor)
1) Is there an advantage in using an LC filter over a RLC filter? I
2) Do I need to match the impedance of the filter to the output impedance of a buffer amplifier? If so, can someone please point me to how I calculate and match the impedance of the filter? I'd like to learn about how to do this.
Regards.
1) Is there an advantage in using an LC filter over a RLC filter? I
2) Do I need to match the impedance of the filter to the output impedance of a buffer amplifier? If so, can someone please point me to how I calculate and match the impedance of the filter? I'd like to learn about how to do this.
Regards.