Casella CEL CEL-393 - Manual (Page 6)

on the main digital display. In addition, the computer is continually
sampling this level every 15ms, and the data is used to calculate the
noise rating parameters.
These parameters are the L eq , L Tm3 , L Tm5 , L max and three L n values.
The statistical L n parameters calculated are normally L 10 , L 50 and L 90 ,
however, alternative values are available on option. They are described
in Chapter 2 of this handbook.
The computed results are available throughout the current period along
with the SPL, and are continually updated and therefore always correct.
A comprehensive memory facility for these results is also provided and
this operates in four distinct modes. The memory modes provided are:
890009
Internal Data Bus
RAM
Pro-
cessor
ROM Digital
Interface
CEL-160
Level
Recorder
Overload
Control
Logic
Display
Display
Driver
Oct/
1 / 3 Oct
Filter
Operator
Control
Matrix
Operator
Control
Matrix
Level
Recorder
Interface
Power
Supply
Intl/Extl
CEL-238
Sec'dary
Pr'ssor
D A
Log DC Output
A-Wgt
F P I S
Range
Control
System
Conditioned AC Output
RMS
Optional
CEL-2942A/5
Cable
CEL-299
Preamplifier
CEL-186
Microphone
Optional
CEL-2962
Windshield
Optional
CEL-3025
Vibration Kit
Figure 1 Block diagram of CEL-393B
/2. 393 Handbook