A special oscilloscope that displays an X-Y plot of two signals so as to indicate their relationship.(noun)
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Use "vectorscope" in a sentence
"· This vectorscope is overlaid directly on top of the video, so you can see how adjustments in lighting and the camera controls affect the brightness and saturation of the colors."
"A vectorscope will help perfectly light a chroma key backdrop."
"G Series monitors feature a built-in waveform monitor with over-level function, vectorscope with selectable size and position, advanced audio level meter, and LTC/VITC time code support."