The oscilloscope is an electrical laboratory device that is used to graph, display, and analyze the characteristics of any given circuit, electrical system or component. Generally it displays waveforms of alternating current or fluctuating current, having a frequency in the range of 1 Hz to 1 MHz.
A vector scope is an oscilloscope oriented tool that is used for both audio and video purposes. It is generally taken for identification, measurement and displaying of the color characteristics of a video signal.
The Major Distinction Between Oscilloscope versus Vector Scope
The primary difference between oscilloscope and vector scope lies in the use of an axis. In the oscilloscope, different signals, generally voltage is taken in the y-axis, and time or frequency is taken at the x-axis. On the contrary, in vector scope, two signals are each taken in the both axis.
So we can say, an oscilloscope helps us to identify and analyze the characteristics of an electrical device, while a vector scope assists us to reduce the saturations of video images.
Difference in purposes and axis
An oscilloscope displays live screening of graphical relationship between the voltage and time. The vertical axis represents the voltage measurement while the horizontal axis represents the time, or at times the frequency.
The vector scope is an electrical layout that has a broad similarity with a general oscilloscope, but here graphical relationship between two electrical signals is exhibited. The horizontal line represents the hue, while the vertical line represents the saturation.
Audio Vector Scope
An audio vector scope is used to measure the difference between channels of stereo audio signals. It visualizes the spectral content of a sound in a similar way to a video vector scope. It analyzes the audio characteristics of an audio recording, in order to detect clipping, hum, resonances or fluctuating frequency responses.
Working Mechanism of an Oscilloscope
The signal is to be viewed on the screen being applied across the Y-plates of CRT. To see the waveform of the input signal, it is essential to spread it horizontally from left to right, which is done by applying a saw-tooth voltage wave to X-plates. Under these conditions, the electron beam would move uniformly thereby graphing vertical vibrations of input signal with respect to time.
Due to repetitive tracing of the viewed waveform, a continuous display is obtained because of persistence of vision. To get a stable stationary display on the screen, the input signal across the Y-plates must be synchronized with the horizontal sweeping of the beam.
Working Mechanism of a Vector Scope
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 color 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—color 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 distance from the center 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 color bars video test signal, including boxes around the circles for the colors 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 color bars, while their PAL counterparts have phase 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.
What is the line on a vector scope?
The line between red and yellow on the Selective Vector scope is the Skin Tone line, which allows us to effectively check for the accuracy of all skin tones in the footage. All skin types should fall along this line if we want them to look realistic.
Conclusion
Oscilloscopes are built for mainly troubleshooting malfunctioned electronic equipment. It can also 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 plays 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.
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