HP 416A - Page 73

Atten. #2
Model 416A
Model 416A Meter
Setting
RANGE Switch Setting
Indication, DB Scale
10 DB 0 DB
100%
5
30 DB
- 10 DB
30%
15
50 DB
- 20 DB
10%
25
70 DB
- 30 DB
3%
35
2 . Return attenuator #2 to the 0 DB setting .
Noise Level -
l. Recheck the range tracking , at full scale, on all ranges, using the
following settings .
Atten. #2
Model 416A DB Scale
Setting RANGE Switch Setting
Reading
, Indication
0 DB
0 DB
100% 0 0
20 DB
- 10 DB
30%
0
-
10
40 DB - 20 DB
10%
0 - 20
60 DB - 30 DB
3%
0
-
30
·z. Return the setting of attenuator #2 to 0 DB.
3 . Increase attenuation at attenuator # 1 in 10 - db steps down to ~ 70 db.
Check that there is no change in the meter full - scale indication . On the final
reading , look for excess i ve noise (instability of the meter indication).
4. Increase attenuation at attenuator #2 in 10 - db steps down to - 80 db .
At every 20 - db increase in attenuation , reset the Model 416A RANGE switch.
a . With attenuator #2 set at 70 DB , note
meter tracking and indication of noise .
On the DB scale , the meter should in -
dicate approximately 35 ±1 db . (At
35 db , if the deviation is within ±1 db
noise is within permissible limits.)
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I .