Casella CEL CEL-278 - Manual (Page 14)

Normally when the Filter Set is used with CEL sound level meters, (except
for the CEL-493/2 series), the CEL-278/2 RANGE switch is set to "Hi" so that
the upper 70dB of its dynamic range is brought into operation.
When used with the CEL-493/2 series of sound level meter, the normal
position of the RANGE switch for frequency analysis is "Lo", which
corresponds to the bottom 70dB of the meter's range. However, due to the
extremely wide dynamic range of the CEL-493/2, if the input from the sound
level meter is within the top 30dB of its chosen range, the Filter Set may
overload. Should such an overload occur, move the Filter Set RANGE
switch to "Hi" and use the top 70dB of its range.
In either case, if an overload occurs during a measurement, move the
RANGE switch on the sound level meter to a higher range in order to obtain
valid readings.
WTNG: All Pass - C - Oct
In the "All Pass" position the signal from the associated Sound Level Meter
is fed straight to the output without passing through either filter network.
In the "C" position, the input signal is passed through a C-weighted filter.
In the "Oct" position, the input signal is passed through the octave filter. The
centre frequency of this filter may be stepped manually or by remote control
from an external device. Complete results from the "Octave" setting include
an All Pass band level, followed by octave band levels over the frequency
range from 16Hz to 16kHz.
"Up" and "Down" Nudge Buttons
The
and nudge buttons at either side of the front panel are used to
select the next highest or next lowest filter band centre frequencies when
scanning the Filter Set manually.
Page 14 CEL-278/2 Handbook CEL Instruments Ltd