Detector (Latin detector — discoverer, from detego — to uncover, to detect) in radio engineering is a device for extracting the useful signal from electrical oscillations. The detector of a radio receiving device, or demodulator, restores the information from a radio signal that was embedded in it by a modulator. Detectors are used in broadcast, communication, and television radio receivers.
There are amplitude detectors for extracting signals encoded using amplitude modulation, frequency detectors for extracting signals encoded using frequency modulation, pulse-width detectors for retrieving information carried by pulse-width modulation, and detectors for other types of modulation.
In measuring instruments, oscillations are detected to extract certain signal parameters: root mean square or pulse values, current average signal power, etc. Depending on the application, the principle of operation and circuitry of detectors may vary.
Modern digital detection methods are based on real-time computation of functions for extracting the signal envelope, which reflects the transmitted information. These methods allow more precise extraction of the useful signal even when the carrier frequency and the extracted oscillations differ slightly. This principle is used in direct amplification receivers based on the RDA1846 chip.
Related articles: CTCSS pilot tone, Pilot tone modulation, Polar modulation, Radio signal modulation, Types of modulation, Demodulation and signal detection.