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User Manual 49
Change the Horizontal Format
Press the Acquire button on the front panel; then press the XY soft key to set the XY(On)
or YT(Off) mode. The default setup is YT .
YT
It is the normal viewing mode for the oscilloscope. In the Normal time mode, signal events
occurring before the trigger are shown to the left of the trigger point and signal events
after the trigger point are displayed to the right of the trigger point.
XY
XY mode changes the display from a volt- versus- time display to a volt- versus- volt
display. Channel 1 amplitude is plotted on the X- axis and Channel 2 amplitude is plotted
on the Y- axis, the two channels will be turned on or off together.
You can use XY mode to compare frequency and phase relationships between two
signals. XY mode can also be used with transducers to display strain versus displacement,
flow versus pressure, volts versus current, or voltage versus frequency.
The phase deviation between two signals with the same frequency can be easily
measured via Lissajous method. The figure below shows the measurement schematic
diagram of the phase deviation.
According to sin θ =A/B or C/D (wherein, θ is the phase deviation angle between the two
channels and the definitions of A, B, C and D are as shown in the figure above), the phase
deviation angle is obtained, that is: θ = ± arcsin (A/B) or ± arcsin (C/D)
If the principal axis of the ellipse is within quadrant I and III, the phase deviation angle
obtained should be within quadrant I and IV, namely within (0 to π/2) or (3π/2 to 2π). If the
principal axis of the ellipse is within quadrant II and IV, the phase deviation angle obtained
should be within quadrant II and III, namely within (π/2 to π) or (π to 3π/2).
X-Y function can be used to measure the phase deviation occurred when the signal under
test passes through a circuit network. Connect the oscilloscope to the circuit to monitor the
input and output signals of the circuit.