CR:270 Series User Manual
Page 21
IEC 804 11.2.20 & IEC 651 11.2.21
The warm up period is 4 minutes although it is normally ready within 60 secs.
IEC 804 11.2.21
The settling time before valid Leq readings are obtained is one minute.
IEC 804 11.2.22
The nominal battery life is 10 hours continuous use.
IEC 651 11.2.22
Not applicable.
IEC 804/651 11.2.23
See microphone data.
IEC 804/651 11.2.24
See microphone data.
IEC 804/651 11.2.25
Dummy microphone impedance is 18 pF in series with 50ohm.
IEC 651 11.2.26
Primary indicator range is 87dB to 97dB on the centre range.
IEC 651 11.2.27
Manual only.
IEC 804 11.2.26
+1dB at all frequencies greater than or equal to 31.5Hz.
IEC 804 11.2.27
The instrument can be factory set for free field or diffuse field use.
IEC 804 11.2.28
The indicator range is identical to the linearity range of IEC 804 11.2.4
Additional Octave information
The CR:274 meets IEC 1260 Type 2 whilst the CR:273 meets IEC 1260 Type 1. The
specification IEC 1260 requires that this manual provides detailed information to verify
that the specifications are met. While much of the data required is in the body of this
manual, the points required to be detailed are listed below in the order in which they
occur in the IEC specification. The numbers marked after the IEC number refer to that
documents paragraph numbers for reference.
IEC 1260 7a
The octave filters comply with all performance requirements of IEC 1260 with class 2
for the CR:274 and class 1 for the CR:273
IEC 1260 7b
The filters are designed using analog filters. The filter centre frequencies are changed
by switching in different resistors and capacitors CMOS analog switches controlled by
CMOS digital circuitry.
