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Signal sampling representation. The continuous signal S(t) is represented with a green colored line while the discrete samples are indicated by the blue vertical lines. In signal processing, sampling is the reduction of a continuous-time signal to a discrete-time signal. A common example is the conversion of a sound wave to a sequence of "samples".
Instead, the sampling of the signal should be made in a short enough interval that it can represent the instantaneous value of the signal with the highest frequency. This means that in the FM radio example above, the sampling circuit must be able to capture a signal with a frequency of 108 MHz, not 43.2 MHz.
In the early 1980s, a 32 kHz sampling rate was used in broadcast (esp. in UK and Japan), because this is sufficient for FM stereo broadcasts, which have 15 kHz bandwidth. Some digital audio was provided for domestic use in two incompatible EIAJ formats, corresponding to 525/59.94 (44,056 Hz sampling) and 625/50 (44.1 kHz sampling).
In radio communications, for example, bandwidth is the frequency range occupied by a modulated carrier signal. An FM radio receiver's tuner spans a limited range of frequencies. A government agency (such as the Federal Communications Commission in the United States) may apportion the regionally available bandwidth to broadcast license holders ...
FM radio: PAL: used as sampling frequency for ADCs for digitizing the 10.7 MHz intermediate frequency in software-defined radio implementations of AM/FM radio receivers. [17] Pixel clock of some PAL CCD cameras (raw image resolution of 912×625). [18] Used in PAL version in some early Apple computers, e.g. Apple II Europlus. 14.318182 NTSC
The frequency spectrum of a typical radio signal from an AM or FM radio transmitter. The horizontal axis is frequency; the vertical axis is signal amplitude or power. It consists of a signal (C) at the carrier wave frequency f C, with the modulation contained in narrow frequency bands called sidebands (SB) just above and below the carrier.
If one desired to sample an FM radio broadcast centered at 87.9 MHz and bandlimited to a 200 kHz band, then an appropriate anti-alias filter would be centered on 87.9 MHz with 200 kHz bandwidth (or passband of 87.8 MHz to 88.0 MHz), and the sampling rate would be no less than 400 kHz, but should also satisfy other constraints to prevent aliasing.
An American FM radio transmitter in Buffalo, NY at WEDG. Edwin Howard Armstrong (1890–1954) was an American electrical engineer who invented wideband frequency modulation (FM) radio. [12] He patented the regenerative circuit in 1914, the superheterodyne receiver in 1918 and the super-regenerative circuit in 1922. [13]