In radio electronics or acoustics, spectral splatter (also called switch noise) refers to spurious emissions that result from an abrupt change in the transmitted signal, usually when transmission is started or stopped.[1]
Frequency spectrum of a non-splattering PSK31 signalFrequency spectrum of a splattering PSK31 signalSpectral plot of the 27 MHz band during a band opening showing severely distorted and splattered voice signals
For example, a device transmitting a sine wave produces a single peak in the frequency spectrum; however, if the device abruptly starts or stops transmitting this sine wave, it will emit noise at frequencies other than the frequency of the sine wave. This noise is known as spectral splatter.
When the signal is represented in the time domain, an abrupt change may not be visually apparent; in the frequency domain, however, the abrupt change causes the appearance of spikes at various frequencies.
A sharper change in the time domain usually results in more spikes or stronger spikes in the frequency domain. Spectral splatter can thus be reduced by making the change more smooth. Controlling the power ramp shape (i.e. the way in which the signal increases ("power-on ramp") or falls off ("power-down ramp")) can help reduce the splatter. In some cases one can use a filter to remove unwanted emissions. Note that a completely abrupt change (in the mathematical sense) is not possible in physical reality; the change is always somewhat smoothed naturally, for example due to the capacitance (in electronics) or inertia (in acoustics) of the components involved.
In radio electronics, the need to minimize spectral splatter arises because signals are usually required by government regulations to be contained in a particular frequency band, defined by a spectral mask. Spectral splatter can cause emissions that violate this mask.
^"Temporal resolution The ability to follow rapid changes in a sound over time" (PDF). University of Washington. Retrieved February 12, 2024.
January 01, 1970
spectral, splatter, radio, electronics, acoustics, spectral, splatter, also, called, switch, noise, refers, spurious, emissions, that, result, from, abrupt, change, transmitted, signal, usually, when, transmission, started, stopped, frequency, spectrum, splatt. In radio electronics or acoustics spectral splatter also called switch noise refers to spurious emissions that result from an abrupt change in the transmitted signal usually when transmission is started or stopped 1 Frequency spectrum of a non splattering PSK31 signal Frequency spectrum of a splattering PSK31 signal Spectral plot of the 27 MHz band during a band opening showing severely distorted and splattered voice signals For example a device transmitting a sine wave produces a single peak in the frequency spectrum however if the device abruptly starts or stops transmitting this sine wave it will emit noise at frequencies other than the frequency of the sine wave This noise is known as spectral splatter When the signal is represented in the time domain an abrupt change may not be visually apparent in the frequency domain however the abrupt change causes the appearance of spikes at various frequencies A sharper change in the time domain usually results in more spikes or stronger spikes in the frequency domain Spectral splatter can thus be reduced by making the change more smooth Controlling the power ramp shape i e the way in which the signal increases power on ramp or falls off power down ramp can help reduce the splatter In some cases one can use a filter to remove unwanted emissions Note that a completely abrupt change in the mathematical sense is not possible in physical reality the change is always somewhat smoothed naturally for example due to the capacitance in electronics or inertia in acoustics of the components involved In radio electronics the need to minimize spectral splatter arises because signals are usually required by government regulations to be contained in a particular frequency band defined by a spectral mask Spectral splatter can cause emissions that violate this mask See also editGibbs phenomenonReferences edit Temporal resolution The ability to follow rapid changes in a sound over time PDF University of Washington Retrieved February 12 2024 Retrieved from https en wikipedia org w index php title Spectral splatter amp oldid 1206585392, wikipedia, wiki, book, books, library,
