Filters & Frequency Response
Every filters & frequency response calculator on CalcEngines — unit converters, derived indices and interpretive tools, each with its formula, a worked example and the reference intervals it is judged against.
7 calculators in this section
- Anti-Aliasing Filter CalculatorHow much attenuation your anti-aliasing filter has to reach before anything folds back into the band you care about — derived from the converter's own resolution — and the filter order that gets there across the transition the sample rate leaves you, with the corner frequency it implies and what oversampling would save.
- Control Loop Stability CalculatorEnter a loop gain — a DC or integrator term, a resonant pole pair, zeros and poles — or let the page build the plant from a buck output stage, and get the crossover frequency, the phase margin, the gain margin and the step-response overshoot that phase margin implies, with the Bode plot that shows where they are read.
- EMI Input Filter CalculatorThe LC filter in front of a switching converter, and the stability question that comes with it. A regulated converter presents a negative incremental resistance to its input, so an undamped filter can make a working converter oscillate. This page gives the corner, the attenuation at the switching frequency, the filter's output impedance peak, the Middlebrook verdict, and the parallel R–C damping branch that fixes it.
- Filter Response Order CalculatorGive a passband edge with an allowed droop and a stopband edge with a required attenuation, and get the order Butterworth, Chebyshev type I and Bessel each need — with the attenuation each actually reaches, the −3 dB frequency each ends up with, and the group delay at DC that makes the Bessel argument a number rather than an opinion.
- Multiple-Feedback (MFB) Filter CalculatorSecond-order low-pass or band-pass in the inverting multiple-feedback topology: the three resistors and two capacitors for the cut-off or centre frequency, Q and gain you want, the nearest E-series parts, the response those real parts actually give, and the op-amp speed it needs.
- RC and RLC Filter CalculatorCut-off or resonant frequency, Q and bandwidth of an RC low-pass or high-pass filter, a series RLC band-pass or a second-order RLC low-pass, with the gain and phase at any frequency and a Bode plot.
- Sallen-Key Active Filter DesignerSecond-order Sallen-Key low-pass or high-pass, unity-gain or equal-component, to a Butterworth, Bessel or 0.5 dB Chebyshev response: the exact R and C values, the nearest E-series parts, the response those real parts give, the op-amp speed it needs, and the Bode plot.