Casella CEL CEL-63X - Manual (Page 56)

CEL-63x Environmental & Occupational Noise Meter
56 Casella CEL
analysis and graphing tools, which you can use to analyse and view
measurement runs.
Contact Casella CEL for more information about the insight program.
AC and DC output port
The AC and DC output port is a 2.5 mm stereo jack. It has two functions:
The tip connection (1) provides an
AC output from the instrument.
You can use this output for remote
monitoring, and for providing a
signal to a separate recording
device or headphone amplifier.
The AC output level is
approximately 0.4 Vrms full scale, which corresponds to a sound
pressure level of 96 dB with AC Low Output selected (refer to the note
on page 26 for more information). The output impedance is
approximately 2.2 kΩ. The AC output corresponds to the Z-weighted
response of the instrument.
If you use the AC output, you should make certain the load impedance is
as high as possible, and you should use a co-axial cable of length 0.5 m
to 10 m.
The ring connection (2) provides a DC output voltage that is
proportional to the measured sound pressure level. The DC output
voltage is scaled linearly at 0.01 V/dB with a maximum value of 1.4 V
DC, which represents 140 dB.
The output impedance is approximately 2.2 kΩ. The DC output
corresponds to the A-weighted fast time response of the instrument.
If you use the DC output, you should make certain the load impedance is
as high as possible.
The signal ground for the AC output and for the DC output is on the barrel
connection (3). The signal ground must be isolated from the ground connection
of the DC power input when you use a mains DC supply.
High-level noise measurements
The CEL-63x instrument may be used to measure sound pressure levels up to
165 dB when used in conjunction with microphone -MIC1. To set the
instrument to the 140 dB or the 165 dB full-scale measurement mode, refer to
the System Tools menu (see the note on page 26).