Illustration 6 : Using The X-Y Function - Tenma 72-8710 Operating Manual

DSO Series User Ma nual

Illustration 6 : Using the X-Y function

To check the phase difference between two channels.
Example : To measure the phase variation when a signal passes
through the circuit, connect your oscilloscope to the circuit and
monitor the input and output signals. To check the circuit's input and
output in the X-Y coordinate mode, follow the steps below :
1. Set the attenuation factor of the probe to 10X. Set the switch of the
probe to 10X.
2. Connect the CH1 probe to the input terminal of the network.
Connect the CH2 probe to the output terminal of the network.
3. If the channel is not displayed, press the [CH1] and [CH2] menu
button to enable the two channels.
4. Press [AUTO].
5. Adjust the vertical scale knob to make the displayed amplitude of
the two channels to about equal.
6. Press the [DISPLAY] menu key to recall the display menu.
7. Press F2 to select X-Y. The oscilloscope will display the circuit's
input and output characteristics in a Lissajous figure.
8. Adjust the vertical scale and vertical position knob to achieve
the best result of waveform.
9. Using the elliptic oscilloscope display graph to observe, measure
and calculate the phase difference. (see the figure below)
Signal must be
horizontally central
Figure 3-7
A C
If sin θ = ,
or
B D
θ is the angle of disparity between the channels. For definitions of A,
B, C, D see the above figure. Calculating with this formula, the
angle of disparity is
A
± ±
θ = ) or θ =
arcsin( arcsin (
B
If the elliptic main axis is within quadrants I and III, the angle of disparity
should be within quadrants I and IV, i.e. inside (0~ ) or (
If the main axis is within quadrants II and IV, the angle of disparity should
be within quadrants II and III, i.e. inside (
C
)
D
π
3π
~ 2π ).
2
2
π 3π
π
~ ) or ( ~ π ).
2
2
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