narrow-band amplifier
31Common emitter — Figure 1: Basic NPN common emitter circuit (neglecting biasing details). In electronics, a common emitter amplifier is one of three basic single stage bipolar junction transistor (BJT) amplifier topologies, typically used as a voltage amplifier.… …
32Electronic filter — Electronic filters are electronic circuits which perform signal processing functions, specifically intended to remove unwanted signal components and/or enhance wanted ones. Electronic filters can be:*passive or active *analog or digital *discrete …
33RF MEMS — The MEMS acronym stands for Micro Electromechanical System and is used to refer to components of which sub millimeter sized parts need to move for the components to have electronic functionality. RF MEMS passives, such as capacitors, inductors,… …
34Dipole antenna — A schematic of a half wave dipole antenna connected to an unbalanced coaxial cable. Better practice is to connect the balanced dipole to the unbalanced line with a balun. A dipole antenna is a radio antenna that can be made of a simple wire, with …
35Heterodyne — This article is about waveform manipulation. For the use of the term in poetry, see Heterodyne (poetry). For the webcomic characters, see Girl Genius. Heterodyning is a radio signal processing technique invented in 1901 by Canadian inventor… …
36TV and FM DX — TV DX and FM DX is the active search for distant radio or television stations received during unusual atmospheric conditions. The term DX is an old telegraphic term meaning long distance. VHF/UHF television and radio signals are normally limited… …
37Electronic oscillator — An electronic oscillator is an electronic circuit that produces a repetitive electronic signal, often a sine wave or a square wave.A low frequency oscillator (LFO) is an electronic oscillator that generates an AC waveform between 0.1 Hz and 10 Hz …
38Light pollution — This article is about light pollution in the visible spectrum. For information on pollution in the radio spectrum, see radio spectrum pollution. This time exposure photo of New York City at night shows skyglow, one form of light pollution …
39Coherent state — In quantum mechanics a coherent state is a specific kind of quantum state of the quantum harmonic oscillator whose dynamics most closely resemble the oscillating behaviour of a classical harmonic oscillator system. It was the first example of… …
40Bat detector — The term bat detector is usually used to describe a device used to detect the presence of bats by converting their echolocation ultrasound signals to audible frequencies as they are emitted by the bats. There are other types of detector which… …
