Simpson 886-2, Руководство оператора, Страница: 8 / 24

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5. Meter: Pivot and Jewel movement with 2-1/2” dial
having end markings of -10 dB and +10 dB, and
fifteen 1 dB scale markings. From -5 dB to +10 dB
the accuracy and scale markings comply with the
ANSI specification for a Type 2 instrument.
6. Speed of Response: Types of response: Selectable “Slow” or “Fast” re-
sponse times meet the exponential-time-averag-
ing characteristic required by the ANSI specifica-
tion for a Type 2 instrument.
SLOW Response: Response to a 500 millisecond tone burst of 1000
Hz is nominally 2.5 dB down from a reference
steady state signal at the same level and fre-
quency. Overshoot response to a suddenly ap-
plied steady state signal is less than 0.5 dB. When
an applied signal is turned off, the decay rate is
less than 3 seconds per 10 dB.
FAST Response: Response to a 200 millisecond tone burst of 1000
Hz is nominally 2.0 dB down from a reference
steady state signal at the same level and fre-
quency. Overshoot response to a suddenly ap-
plied steady state signal is less than 0.5 dB. When
an applied signal is turned off, the decay rate is
less than 0.5 seconds per 10 dB.
7. Linearity: Primary indicator range is from 0 dB to +10 dB on
each range. Overall indicator range is -5 dB to
+10 dB. The dedicated “OSHA” range primary
indication is +105 dB to +115 dB, with an overall
indication of +100 dB to +115 dB. Within these
limits, the primary indicator accuracy is .1 dB and
the overall accuracy is 1.5 dB.
8. Calibration: Recommended calibration frequency is 1000 Hz
at sound pressure levels of either 94 dB on the 90
dB range, or 114 dB on the 110 dB range. Cali-
bration is screwdriver adjustable from side of case.
9. Output Connections: This Instrument is equipped with three outputs:
External Filter, RMS Output, and dB Output.
External Filter: Provides non-weighted (flat response) output of
120 mV RMS, at meter reading of +10 dB, into a
100 K
⍀
load; a lower impedance may affect the
meter reading. This output is not affected by the
“Fast-Slow” setting. The recommended plug is
Switchcraft’s #750 (0.141" diameter).
RMS Output: Provides weighted or non-weighted output of 1.00
V RMS, at a meter reading of +10 dB, into a 100
K
⍀
load; a lower impedance will not affect the
meter reading. This output is not affected by the
“Fast-Slow” setting. The recommended plug is
Switchcraft’s #850 (0.097" diameter).