27
Figure 21. IMPULSE Response
Figure 22.
IMPULSE
Response to
Repeated
Impulses
28
VI. SPECIFICATIONS
Standards: Meets or exceeds ANSI S1.4-1983, Type 1 and relevant sections of
IEC 651-1979, Type 1(I) and IEC 804-1985.
Display: 3 1/2 Digit Liquid Crystal Display with an additional
Quasi-Analogue 60 dB indicator in 2 dB increments. Level display indicates
to 0.1 dB resolution. Time display indicates either Min:Sec or Hr:Min.
Annunciators are included for Battery Check, Hold, and Overload Indication.
Printout: When used with a printer, a one page printout is produced. It
consists of the following: Heading; WEIGHTING and RESPONSE settings; LEQ,
MAX, MIN, and SEL levels; RUN TIME and OL TIME; EXCEEDANCE LEVELS (dB) with
1 dB resolution; and Filter Data for each frequency (LEQ, MAX, MIN, and SEL)
along with the RUN TIME and OL TIME for each frequency.
Modes of Operation: Sound Pressure Level (SPL), Maximum Level (MAX), Minimum
Level (MIN), Sound Exposure Level (SEL), and Equivalent Level (LEQ). Peak
Level (PEAK) and Impulse Level (IMP) can also be measured.
Minimum Measurement: Meter only; With Model QE4146 Microphone -- 27 dBA.
Using Linear Weighting with an Octave Filter Set; See Figure 17. The minimum
measurement varies depending on the filter frequency selected.
Maximum Measurement: With Model QE4146 Microphone -- 120 dB with 20 dB Crest
Factor. (140 dB if measuring a sinusoidal signal.) Overload indication will
occur if upper range is exceeded.
Frequency Weighting Networks: A, B, C, and Linear. When using a filter set,
any one of the weightings may be selected.
Meter Response: Slow, Fast, Impulse, and Peak. (The Peak onset time
constant is less than 50 microseconds). Peak measurements may be made in
either A, B, C, or Linear Weighting.
Microphones: Removable precision 1/2 inch prepolarized condenser (electret)
microphone is standard. Optional 1/2 inch, one inch, and other microphones
are available.
Preamp: Removable. The input impedance is greater than 1G ohm in parallel
with 2 pF. The preamp will drive up to 100 feet of cable with no loss. (See
Figure 14.)
Polarization: Regulated 200V DC within 2% when using condenser microphones.
The voltage must be manually switched off when using prepolarized condenser
(electret) microphones.
