Cirrus Research CR308, Instrument Handbook

Page: 16 / 28

Page 16 CR:308 & CR:310 – User Manual
8 Specifications and technical information
8.1 Instrument specifications
Applicable standards IEC 61672-1: 2013 Class 2
Measurement range 30dB(A) – 130dB(A)
40dB(C) – 130dB(C)
Frequency weighting A and C
Time weighting Fast (F) and Slow (S)
Display functions Normal, Maximum, Minimum, CPeak
Measurement functions LAF, LAS, LCF, LCS, LCPeak
Noise floor <25dB(A) and 35dB(C)
Display flags Alarm limit, overload and under-range
Auto calibration range ±4.5dB
Reference point 94dB (1kHz), 92.9dB (8kHz)
Settling time 60s
Display Backlit 128x64 LCD
Resolution 0.1dB
Electrical input 5V power-in via mini-USB
Power 2 x AA/LR6 1.5V batteries or 5V DC via mini-USB input
Battery life 24 hours with alkaline batteries
Microphone ½” pre-polarised electret condenser type HY:205
Operating temperature 0°C to +40°C
Operating humidity 25% – 90%
Atmospheric pressure 65kPa – 108kPa
Storage temperature -20°C to +60°C
Dimensions 215mm x 68mm x 32mm
Weight (including batteries) 220g
Electrical outputs AC (tip 3.5mm jack) and DC (middle 3.5mm jack)
DC output Voltage 15mV/dB, range 450mV – 1950mV
AC output RMS 2V
8.2 Reference information for periodic testing
Reference level (1kHz) 94dB
Reference level (8kHz) 92.9dB(A)
Linear range 8kHz
30 – 130dB
Linear range 4kHz 30 – 130dB
Linear range 1kHz
30 – 130dB
LCPeak maximum (500Hz,
1kHz, 8kHz)
133dB
Self-generated noise floor
A-weighting = 25dB
C-weighting = 35dB
Self-generated noise floor
(with mic fitted)
A-weighting = 25dB
C-weighting = 35dB
Dummy microphone
capacitance
18pf
Recommended dummy
microphone
KP:66