Single Channel EEG Test System | User Manual
19
•
Confirm all values are within 1% or
5µV of the set value
•
Note: The Fluke 8845A has suitable
accuracy at 10mVpp but has
borderline accuracy at 1mVpp and
lower. An alternate method is to
measure the output at BNC2 and then
use the divider ratio above.
DC offset
(fixed
±150mV)
150mV ±1%
Method:
⚫
Set the equipment to “Off”
⚫
150mV
⚫
Measure the voltage between Ch1
and Ch2
Note: the DC offset is sourced from an
internal super capacitor which will discharge
after ~10min. Tests in the standard are
typically less than 2 minutes.
DC variable
Setting ±5mV
or 1%
Use the following procedure:
⚫
Set the equipment to “Off”
⚫
Select the “Variable” checkbox
⚫
Set to +200mV dc offset
⚫
Confirm the value is 200±5mV
⚫
Repeat for +600, +1000, -200, -600
and -1000mV
Output
frequency
Setting ±1%
Method:
•
Set up 1mVpp 10/40Hz sine wave
•
Measure the frequency at BNC2 using
any appropriate meter
⚫
Note: this verifies whether the system
clock is accurate. Verification of other
frequencies or timing is not as this is
covered by software validation,
although users are free to measure
other frequencies and timing. The use
of 40Hz is recommended to avoid
beating with mains frequency.