Current location - Education and Training Encyclopedia - Graduation thesis - The design problem of Butterworth low-pass filter! What is the normalized cutoff frequency?
The design problem of Butterworth low-pass filter! What is the normalized cutoff frequency?
As the name implies, normalized frequency is that no matter what frequency is classified as 1, which is used to design filters of any frequency.

That is, you first design the filter of 1Hz, and then push it to 100Hz. The way to deduce it is to multiply all the frequency-related components in the network by a coefficient: all L decreases by 100 times, and the inductance wL remains unchanged; All C is also reduced by 100 times, and the capacitive reactance is 1/wC unchanged.

If there is still "normalized impedance" (1ω), continue recursion. For example, if it is used in a 50 Ω system, it is 50 times larger than the normalized impedance, and all L needs to be expanded 50 times, and the inductance needs to be expanded 50 times. All capacitors are reduced by 50 times, and the capacitive reactance is 50 times larger.