Larson Davis System 824, Technical Reference Manual

Page: 505 / 673

9/29/09 A -49
The “F” is the check character for
the S205, 0 command. A detailed
description of the protocol is
available from Larson•Davis and the
latest revisions of software utilize
the protocol.
This setting is set to the noise floor
of the instrument so that it can
properly indicate “Near Noise Floor”
messages when within 10dB of the
noise floor. It is also used with NF
Compensate, Q208, which will place
the System 824 in an extended
Linearity Range Mode. The true
noise floor of the entire system must
be measured and entered in Q207.
This will vary with the selected input
weighting or microphone sensitivity.
An equivalent microphone
capacitance can be used after
calibration to determine the noise
floor. It may also be possible to
remove the microphone bias to
obtain this value. When properly set
up the linearity range can be
increased by 10dB.
NOTE: The mode is always turned off
with a CAL Change.
S206 Reserved setting
S207 ALL NOISE FLOOR LEVEL
S208 SSA, ISM,
LOG NOISE FLOOR COMP MODE
S209 Reserved setting
S210 ALL AUX CONTROL REG
S211 LOG EXCD RECORD NUMBER