CR:270 Series User Manual
Page 10
CR:273 & CR:274 Additional Functions
General Overview
The CR:273 & CR:274 sound level meters makes
use of virtually the same functions and controls as
the CR:271 & CR:272. The only functional
difference is that the CR:273 & CR:274 has an
octave filter set fitted which meets IEC 1260 to
type 1, with centre frequencies at 31Hz, 63Hz,
125Hz, 250Hz, 500Hz, 1kHz, 2kHz, 4kHz, 8kHz &
16kHz. There is also a FLAT or linear filter instead
of dB(C).
Warning : The power consumption of the
instrument will increase slightly whilst the octave
filters are switched on.
Controls
One extra control is added, a tri-function push
button, labeled OCTAVE FILTER. While the octave
filters are not in use the red filter LED's situated in
the upper most label will all be extinguished.
Switching on the filters
One quick push (duration less than 1 second) of the
OCTAVE FILTER button will switch in the octave
filters, ie make them active. Once the octave filters
are switched in a red LED will be lit in the upper
most label. The lit LED will signify which octave
band filter is currently being utilised.
Selecting the Active filter
To make the next higher octave band filter active
press the OCTAVE FILTER button quickly while the
filters are switched in. This will cause the
instrument to step up to the next octave filter
band, ie if the 1kHz filter LED is lit and the OCTAVE
FILTER button is quickly depressed again then the 2kHz filter LED will light and the
1kHz filter LED will extinguish.
To make a lower octave band filter active depress the OCTAVE BAND button for slightly
longer, for approximately 1 second. This will step down to the adjacent lower octave
filter band.
