A noise detection circuit includes an analog-to-digital conversion (ADC) circuit and a noise event recognition circuit. The ADC circuit is configured to convert an analog signal outputted from a device under test (DUT) into a sequence of digital codes. The noise event recognition circuit, coupled to the ADC circuit, is configured to determine a noise count of the sequence of digital codes, and refer to the noise count to determine if a noise event occurs in the DUT. The noise count indicates a number of times a change in code values between two successive digital codes exceeds a predetermined value.