abolished
by grounding
amp. input
?
fluorescent lights,
fans & motors,
rheostats
turn off source;
shield recording
regular
pattern
?
fundamental
frequency
60 Hz
frequency
?
pure
sinusoid
?
no
yes
>1 kHz
<1 kHz
different
in each amp.
channel
?
yes
no
amplifier
oscillation
use cleanest
channel;
repair amp.
yes
no
electrode
and grounds
intact
?
poorly
regulated DC
power supply
repair amp.
no
yes
15.75 kHz
frequency
?
yes
video monitor
turn off or
move monitor;
shield recording
transients in power
lines or grounds
filter; surge
suppressor
asynch. motors,
engines, generators,
bells, buzzers
turn off source;
shield recording
switching power
supplies, AC bridges
turn off source;
shield recording
yes
no
common mode
rejection failed
repair, replace, or
reconnect ground
and electrode
unshielded lights,
heaters, AC lines
turn off, shield,
or move source;
shield recording
no
no
yes
Figure C.1
Noise Reduction. Start at the top and answer each question posed in the diamonds, following the arrows. At the end, possible noise sources and solutions are proposed. (After Loeb and Gans, 1986.)
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Mouse wheel zooms the figure; click and drag pans across it.