CMRR 3.0E | User Manual
14
6.1.1.2
[Supply Voltage] and [Frequency]
Select [Manual] in [Standard] option, and then select [Voltage]. Now the [Voltage] can choose [Off], [20],
[2.828], [0.5] and [2.0] Vrms (200/56.6/8/1.422/5.66 Vpp) for Supply Voltage Vs (the output voltage of
built-in sine wave signal generator) and 50/60/100/120 Hz for frequency.
After pressing the hole above [Coarse] knob for 6 seconds and launching the hidden voltage of 70.71
Vrms (200 Vp-p), a [70.71 Vrms] option becomes available for voltage Vs. Now it is possible to test a
CMRR value that exceeds the requirement of standards. Although this voltage exceeds all of the standard
requirements, it extends the range of CMRR value
Figure 6-2, Options in [Supply Voltage] and [Frequency]
6.1.1.3
Inner Shield Vc
Once [Supply Voltage] (Vs) is selected, the [Coarse] / [Fine] knobs can be tuned to Inner shield Vc =Vs/2.
This action automatically measures and monitors the voltage that passes variable capacitance Ct with
built-in Vc voltage test circuit. By tuning [Coarse] / [Fine] knobs, the inner Ct is tuned until Ct+Cx (stray
capacitance) =100 pF, where Vc will be half of the output of line frequency signal generator. For example,
when Vs= 20 Vrms, Vc=10 Vrms.
Figure 6-3, voltage display of
“Inner Shield Vc”
