Chapter 2 — Checking Procedure
Checking Procedure
2238 Mediator Integrating Sound Level Meter
Service Manual
BI 5043 –13
19
Table 2.9 Tone Burst Test
Note:
The 2238 handles both Fast and Slow through the same circuit. If there is a
fault, then the whole unit (excluding the microphone and preamplifier) must be
returned as an FRP.
2.3.11 Octave Filter Upgrade
Following an upgrade with Octave Filter ZT 0328, the service technician can choose
to perform the following tests on any or all of the 29 Center Frequencies.
●
Remove the microphone and use adaptor JJ 2614 and JP 0144 to connect the 2238
to a generator.
●
Press
, then
to
About
, then
to select. The last line on the 2238 display
should read
Filter set: Yes
. This shows that you have installed the filter set.
●
Press
once to return to main menu.
●
First, set up to generate a reference signal. Press
and
down to
Weightings
,
then
to select. Start by using
to set the bandwidth to
BB/S
, then
press
down to
Freq. Wtg.
and
to set it to
L
, then
to
OK
and
to
Close
and return to the active display.
●
Set the generator to an appropriate level, and adjust the output until the display
on the 2238 reads 100.0 dB.
●
With this as a reference, press
then
and
to select
Weightings
.
Use
to set the bandwidth to either
1/1-octave/F
or
1/3-octave/F
.
●
The
1/3-octave/F
setting gives access to all 29 Center Frequencies, while the
“
1/1-octave/F
setting provides only 9. Then press
down to “
Center Freq.
and
to set it to the desired frequency. Press
to
OK
and
to
Close
.
●
The 2238 display should read
LxxHzFP
where
xx
is your center frequency. If not,
use
while in the active display to go down to the first line, and
until it reads
correctly.
●
Input a signal from the generator at this frequency. The 2238 display should now
read
100.0 dB
±
0.5 dB.
●
Repeat this sequence for the remaining selected frequencies.
Note:
When measuring frequencies of 50 Hz
or under
, set the weighting to
1/3-
octave/S
. This prevents the reading from short term variations due to the low
Tone Burst
2000 Hz
Acceptance Criteria
in dB re 1 µVRMS
Actual
Reading
Reference
96.0 dB
96.0 dB
Fast (LCFP) – 200 ms
95.0 ± 1.0
Slow (LCSP) – 500 ms
91.9 ± 1.0
Содержание Mediator 2238
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