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{{redirect|Sonograph|the musical recording|Sonograph (EP)}}
{{for|the scientific instrument|Optical spectrograph}}
[[Image:Spectrogram-19thC.png|thumb|
[[File:3D battery charger RF spectrum over time.jpg|thumb|
A '''spectrogram''' is a visual representation of the [[spectral density|spectrum]] of [[frequencies]] of a signal as it varies with time.
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