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JP 0802
JP 0802
273155/1
Fig.4.8.
Control cable AQ 0034
4.2. RECORDING MODE
Level Recorders 2307 and 2309 provide for both AC and DC recording. The criteria for
the selection of recording mode and paper and writing speeds are similar for both Level
Recorders, and are given in some detail in the remainder of this chapter.
The X-Y Recorder Type 2308 has provision for DC recording only. For details of the crite-
ria for selecting sweep speeds, refer to the 2308 Instruction Manual.
4.2.1. AC Recording
When signal rectification, averaging and logarithmic conversion (if applied) are required
to be carried out
in
the graphic recorder, the 2010 READ OUT SELECTOR must be set to
"AC", and thus this mode is known as AC recording
.
Averaging is partly effected by the
inertia of the pen deflection system and cannot therefore be specified as closely as for
DC recording, which is generally preferred for this reason.
Note that the signal in the RECORDER output of the 2010 has a different frequency
from that at the Analyzer input for some settings of the controls.
4.2.2. DC Recording
44
When a signal rectified and averaged in the 2010 is fed to a graphic recorder, the mode
is known as DC Recording. The READ OUT SELECTOR must be set to "DC". This mode
is preferred for most applications because the averaging is constant over the full dy-
namic range of tt:le rectifier (unlike electromechanical averaging), is under the control of
the 2010, and may be varied automatically with frequency by means of a B & T Pro-
gram. It is the only mode which may be used with the Type 2308 X-Y Recorder, which
does not include a rectifier.
Normally logarithmic conversion is performed in the recorder, but it may be performed in
the 2010 by selecting "DC Log" on the READ OUT SELECTOR.
On level recorders the writing speed may be set to the maximum for stable operation.
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