howoscilloscopework

"A vector scope uses an overlaid circular reference display, or graticule, for visualizing chrominance signals, which is the best method of referring to the QAM scheme used to encode colour into a video signal. The actual visual pattern that the incoming chrominance signal draws on the vector scope is called the trace. Chrominance is measured using two methods—colour saturation, encoded as the amplitude, or gain, of the subcarrier signal, and hue, encoded as the subcarrier’s phase. The vector scope’s graticule roughly represents saturation as the distance from the centre of the circle, and hue as the angle, in standard position, around it. "

"The graticule is also embellished with several elements corresponding to the various components of the standard colour bars video test signal, including boxes around the circles for the colours in the main bars, and perpendicular lines corresponding to the U and V components of the chrominance signal (and additionally on an NTSC vector scope, the I and Q components). NTSC vector scopes have one set of boxes for the colour bars, while their PAL counterparts have phases on alternating lines. Another element in the graticule is a fine grid at the nine o’clock, or -U position, used for measuring differential gain and phase."

"Oscilloscopes are built for mainly troubleshooting malfunctioned electronic equipment. It can also be probed between connections of circuits for results. The use of an oscilloscope is also in vogue nowadays to test sensors & outputs of signals of different systems. "

"The vector scopes, on the other hand, have a more distinct application. Vector scopes play a huge role in video applications. It can measure a television signal regardless of its format, leaving the user to easily understand the characteristics of the video signal. It also has a graticule to visualize chrominance signals. Oscilloscopes don’t have this kind of exclusive feature. In the field of audio, vector scopes can also differentiate between channels of stereo audio signals."

"The XY display format can be used to measure the phase relationship between two or more synchronous signals. This measurement technique involves inputting one signal into the vertical system as usual and then another signal into the horizontal system – called an XY measurement because both the X and Y axis are tracing voltages. The waveform that results from this arrangement is called a Lissajous pattern (named for French physicist Jules Antoine Lissajous and pronounced LEE–sa–zhoo). From the shape of the Lissajous pattern, you can tell the phase difference between the two signals."