35
C. Reviewing the Data
To review the data, the meter must be in the Pause mode. Use the Up/Down
buttons on the filter to review the frequencies that were measured. Each
frequency has the following information in memory: SPL, MAX, MIN, SEL, TIME
and LEQ. If an overload occurred during any frequency band measurements, the
OL indicator will appear in the display. OL time can then be recalled by
first placing the mode switch into the TIME mode and then holding the BATTERY
button down.
NOTE: Any frequencies that were not measured will appear as "---" in
the display when the MODE switch selects either SPL, MAX, MIN,
SEL and LEQ. Both TIME and OL TIME will appear as "0:00"
since no run time has elapsed.
X. TECHNICAL INFORMATION
The OB-100 conforms to ANSI S1.11-1986, Order 3, Type 2, Sub-type C and IEC
R225-1966. The normalized passband characteristic of a typical octave filter
response is depicted in Figure 24.
The OB-100 filter is flat within 0.5 dB in the passband, with the 3 dB down
points at approximately .707 fc and 1.414 fc where fc is the center frequency
of the band chosen. The fc/2 and 2fc frequencies are down by approximately
21 dB with the decade points (fc/10 and 10fc) down by greater than 70 dB.
The block diagram of the OB-100 illustrated in Figure 25 traces the signal
input from the Model 1800 through the filters and back to the sound level
meter.
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Figure 24. Typical OB-100 Filter Response
XI.
SPECIFICAT
IONS
Stand
ards:
ANSI
S1.11
-1986
,
Order
3,
Type
2,
Sub-t
ype C
and
IEC
R225-
1966.
Center Frequencies: 10 frequencies from 31.5 Hz to 16 kHz.
Frequency Selection: Full manual control or automatic sequential
stepping through each frequency.
Power Source: Sound Level Meter.
Size: 3.3 x 2.8 x 1.8 inches (84 x 71 x 47mm)
Weight: 6 ounces (170 grams)
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