I
I
I
I
I
I
I
I
I
SIGNAL CONNECTIONS
Probes
Generally, probes offer
the
most
convenient means
of
connecting an
input
signal
to
the
instrument.
They
are
shielded
to
prevent pickup
of
electrostatic interference. The
supplied 1
OX
probe offers a high
input
impedance, which
minimizes circuit loading and allows
the
circuit
under
test
to
operate
very close
to
normal
conditions
thus
providing
accurate measurements. Conversely, it also
attenuates
the
input
signal amplitude by a
factor
of
10.
Coaxial
Cables
Cables may also be used
to
connect
signals
to
the
input
connectors
and may have a considerable
effect
on
the
accuracy
of
a displayed waveform.
To
maintain
the
original
frequency characteristics
of
an applied signal,
only
high-
quality, low-loss coaxial cables should
be used. Also,
cabling should be
terminated
at
both
ends in its characteris-
tic impedance.
If
this
is
not
possible, use suitable
impedance-matching devices.
PROBE COMPENSATION
Misadjustment
of
probe
compensation
is
one
of
the
greatest sources
of
operator
error.
Most
attenuator
probes
are
equipped
with
compensation
adjustments.
To
ensure
optimum
measurement accuracy, always compensate
your
probe before making measurements. Probe
compensation
is
accomplished as follows:
1.
Set
the
appropriate
VOL TS/DIV switch
to
0.1 V and
the
AC-GND-DC switch
to
DC.
2. Preset
instrument
controls
and
obtain
a Normal
Sweep Display presentation (see Basic Oscilloscope
Displays section
of
this manual) using
the
"'='1
kHz
CALIBRATOR square-wave
output
as
the
input
signal. Display several cycles
of
the
CALIBRATOR
square-wave
at
approximately
four
divisions
amplitude.
3.
Check
the
waveform presentation for overshoot and
roll off. Readjust, if necessary,
the
probe com-
pensation for flat
tops
on
the
waveforms (see Figure
11). Refer
to
the
appropriate
probe
manual for
compensation
adjustment
instructions.
@
465B/DM44
Operators
35
To Next Page
Loading...
Need help?
General
