Front-Panel Operation
RMS Versus p-p Amplitude 4
4-17
5502A
CALIBRATOR
!
60V
24V
MAX
OFFSET
ON/OFF
F/C
HOLD
K/J THERMOMETER
51
Connection wiring must match thermocouple type, e.g., K, J, etc.
gvx022.eps
Figure 4-10. UUT Connection: Temperature (Thermocouple)
RMS Versus p-p Amplitude
The Calibrator ranges for sinusoidal ac functions are specified in rms (root-mean-square,
the effective value of the wave form). For example, 1.0 to 32.999 mV, 33 to 329.999 mV,
0.33 to 3.29999 V, etc. The sine wave outputs are in rms, while the triangle wave, square
wave, and truncated sine wave outputs are in p-p. The relationship between p-p and rms
for the non-sine wave types are:
• Square wave p-p x 0.5000000 = rms
• Triangle wave p-p x 0.2886751 = rms
• Truncated Sine wave p-p x 0.2165063 = rms
While the ac function ranges are compatible for sine waves, the rms content of the
other waveforms is less apparent. This quality leads to subtle Calibrator range changes.
For example, if you record a sine wave voltage of 6 V (rms assumed), the selected
range is 3.3 to 32.9999 V. If you then use the softkeys to change from a sine wave to a
triangle wave, for example, the display changes from 6 V rms to 6 V p-p. This
translates to 6 V p-p x 0.2886751 = 1.73205 V rms, and the range switches to 0.33 to
3.29999 V. The Output Display shows the range change because the sine wave voltage
is shown as 6.0000, the resolution for the 3.3 to 32.9999 V range, while the triangle
wave is shown as 6.00000, the resolution for the 0.33 to 3.29999 V range.
You must know the range in operation to record the correct values for voltage offset
because the maximum offsets are specified to the range. For example, the maximum peak
signal for the 3.3 to 32.9999 V range is 55 V while the maximum peak signal for the 0.33
to 3.29999 V range is 8 V. This means in the example above, the 6 V rms sine wave
could have offsets applied to a maximum peak signal of 55 V because the current range is
3.3 to 32.9999 V, while the 6 V p-p triangle wave could have offsets applied to a
maximum peak signal of 8 V because the current range is 0.93 to 9.29999 V. See
“Specifications” in Chapter 1 and “Record a DC Offset” in this chapter for more about dc
offset voltages.
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