Casella CEL CEL-278 - Manual (Page 5)

1. INTRODUCTION
The CEL-278/2 Filter Set was designed to meet the requirement for a
portable filter set that allows octave frequency analysis to be performed with
CEL Sound Level Meters.
This requirement has been realised by utilizing a switched capacitor filter,
that can be switched step by step to give the full range of centre
frequencies. The resulting lightweight instrument has 11 octave bands with
centre frequencies from 16Hz to 16kHz. The accuracy of each individual
filter band achieved in this way fulfils the relevant IEC and ANSI Standard
requirements for octave filters.
The Filter Set is primarily intended to operate while directly fitted to the base
of one of the following sound level meters.
CEL-493/2N Precision Integrating Impulse Sound Level Meter
(Type 1I), CEL-275/2A, /2B, /2C, & /2D Precision Integrating
Impulse Sound Level Meters (Type 1I),
CEL-383/2A, /2B, /2C, & /2D Integrating Impulse Sound Level
Meters (Type 2I).
A factory conversion is available to adapt the following older versions of
these sound level meters so that they can be close coupled to the CEL-
278/2.
CEL-493/2 Precision Integrating Impulse Sound Level
Meter (Type 1I),
CEL-275A & B Precision Integrating Impulse Sound Level
Meters (Type 1I),
CEL-383A & B Integrating Impulse Sound Level Meters
(Type 2I).
CEL Instruments Ltd. CEL-278/2 Handbook Page 5