How to Test Analog Filter Frequency Response

+ Expert Benchtop Waveform and Function Generator

Characterize Filter Performance Across Frequency

Analog filter frequency response measurements can be distorted when source amplitude, output impedance, or connection losses change across the test band. Separating those effects from the filter’s actual behavior requires a stable sine-wave source, a reference measurement at the filter input, and an oscilloscope or analyzer capable of measuring input and output amplitude over the required frequency range.

The test steps the sine-wave stimulus across the passband, transition band, and stopband while keeping the applied level within the filter’s linear operating range. At each frequency, the measurement system compares output amplitude with the input reference and calculates gain. Plotting gain against frequency reveals passband flatness, cutoff frequency, roll-off, and stopband attenuation; phase can be derived from input-to-output timing when required.

Analog Filter Frequency Response Solution

Perform the test by sweeping a sine-wave stimulus across the filter’s passband, transition band, and stopband while measuring the input and output amplitude at each frequency. Keysight Expert Benchtop Waveform and Function Generators provide the controlled stimulus, while an oscilloscope or analyzer captures the filter frequency response. Its frequency-sweep capability enables repeatable stimulus across the test band. Comparing the output amplitude with the input reference produces a gain-versus-frequency trace for evaluating passband flatness, cutoff frequency, roll-off slope, and stopband attenuation. Remote connectivity can support automated frequency stepping and repeatable test execution.

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