Casella CEL CEL-368 - Manual (Page 21)

2. INTRODUCTION
The CEL-268 and CEL-368 Environmental Noise Meters are the first in
a new generation of CEL logging sound level meters designed for envi-
ronmental noise measurement.
In addition to the usual features found on a full specification sound level
meter, these instruments also provide comprehensive calculation, dis-
play and logging facilities that were not previously available in a single
hand held unit. Using well
proven design concepts
and methods that take
full advantage of modern
microprocessor control
and liquid crystal display
technology, they enable a
comprehensive range of
acoustic measurements
to be performed and
stored.
The instruments measure
sound pressure levels in
the range from 10 dB(A) to 140 dB(A) at frequencies between 3.5 Hz
and 20 kHz with the microphone supplied, and up to 70 kHz with a suit-
able microphone.
For example, both frequency and measuring range of the CEL-268 are
extended when an MK-301
1 ⁄
4 " Microphone is fitted to the preamplifier in
place of the standard microphone.
Note that there are no facilities for the connection of external filter
sets for frequency analysis of sound and vibration. However, there
is an analog AC output available suitable for FFT or spectrum analysers.
Both instruments have a similar appearance, the main difference being
the separate
1 ⁄
2 " microphone and preamplifier on the Type 1 CEL-268
The CEL-268 satisfies the requirements
of IEC 804: 1985 Type 1 and ANSI S1.4
1983 Type S.1* for integrating sound
level meters.
The CEL-368 satisfies the requirements
of IEC 804: 1985 Type 2 and ANSI S1.4
1983 Type S.2 for integrating sound
level meters.
* With CEL-192/R Random Incidence Microphone
CEL-268/368 Operator's Handbook - Page 17