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If the DC output from the 2010 is used, the Level Recorder should also
be used in the DC mode. To minimize overshoot while making a DC record-
ing and for the averaging time to override the averaging effect of the pen
system, the Level Recorder's WRITING SPEED control should be set for an
averaging time equal to, or less than, that selected on the 2010.
Once the effective averaging time, and the bandwidth are chosen a limit
is then imposed on the maximum permissible scanning speed. The scanning
speed must not be faster than that which will sweep a range equal to the
bandwidth during a time equal to the averaging time.
This produces the relation
s~~
T
where
S
scanning speed
selected bandwidth
B
T
averaging time - on 2010 for DC
on Recorder for AC
A relation can be derived from this equation, which will fix a value for
the maximum permissible paper speed. An example of this calculation for a
logarithmic sweep is given in Appendix 9.1. The result of this calculation
requires that, using DRIVE SHAFT I of the Level Recorder
p
~
86.6/2 s2 mm/sec
( 1)
where
B is the measurement bandwidth (Hz)
f is the highest measurement frequency (Hz), and
e
is the maximum permissible error
P is the paper speed ( mm/sec)
A similar calculation for a linear sweep (assuming the same scan drive as
for the log sweep) produces the requirement that:
600 e
2
s
2
p~
(2)
fu
where
B is the measurement bandwidth (Hz)
60
fu is the upper limit of the frequency range
(i.e. 2, 20, or 200 kHz), and
e
is the maximum permissible error
P is the paper speed ( mm/sec)
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