LeCroy 9400A

SECTION 9
GETTING THE MOST OUT OF YOUR 9400A
The 9400A is a highly accurate digital oscilloscope which achieves
optimum precision when handled properly.
The purpose of this section is to familiarize the user with operations
and functional hints that will ensure the best possible operation of
the instrument.
9.1
Front Panel Controls
All front panel controls are fully remotely controllable and are
therefore constantly monitored by the 9400A’s internal processor.
Any action performed on the front panel is detected by the processor
and the requested changes are implemented very rapidly.
During data acquisition (measurement of input signals), the internal
processor is also busy with the data-taking controls, calculations and
display generation. Under certain conditions, (e.g. RIS mode or slow
time base), the response time of the front panel controls increases.
When for example, the user tries to move a trace up or down on the
screen, it tends to move with a jumping motion.
Whenever slow response to the control knobs is noticed, set the trigger
mode to SINGLE. Acquisition is stopped, the display of the waveform is
frozen and the response time of control knobs returns to normal. Once
waveform manipulations are done, return to NORMAL or AUTO trigger.
9.2
Accurate Amplitude Measurements
The 9400A digitizers are 8-bit analog-to-digital converters that
measure the amplitude of input signals by subdividing them into 256
levels.
You can ensure maximum measurement accuracy by using the full dynamic
range of the converters, i.e. using input signals close to full scale.
Half-scale signals are in 128 levels only, reducing measurement
accuracy by a factor of two.
To facilitate the adjustment of a full-scale ADC signal, the 9400A
display has been designed to represent the zero level of the ADC as the
bottom line of the grid. Full scale, level 256, is represented by the
top line of the grid.
9-1
Getting the Most Out of Your 9400A