Detector

An electronic circuit that determines the amplitude level of a signal in accordance with certain rules. The simplest type of detector consists simply of a resistor and capacitor, and it measures the average value of a continuous fluctuating DC signal. A more complex but must more useful detector is the RMS detector, which is almost always used in vibration analysis systems. Any type of detector performs an average over time, and the averaging time can theoretically be of any length. It is typically set to be several times longer than the slowest fluctuation period of the signal being detected. Most detectors in vibration analysis equipment have an averaging time of about one second. Detectors are used to determine the levels of frequency domain signals (spectra) as well as time domain signals. Time domain detectors are usually of the analog type, while detectors used in FFT analyzers are digital in operation.

Demodulators used in radio receivers are also called detectors.