LeCroy 9450 - Page 37

9
Bandwidth at
1 MS Input
Impedance
(at
Probe Tip)
The
purpose
of
this
test
is
to
ensure that the entire 9450 system
has a
bandwidth
of at
least
200 MHz
at
probe tip
at
1 MS input impedance.
Set up a
Tektronix
SG
503
Leveled
Sine
Wave
Generator
or equivalent
(note
for the
Marconi
that the maximum amplitude
is
smaller than 5 V):
-
Frequency
.5
MHz
-
Amplitude 5 V
p-p
Terminate
the output
of the
SG
503 via
a 50
S feedthrough and
connect
it
to
the
CHI input
through
a 300
MHz 10 MS
/10
probe using the probe
tip
-
BCN jack.
Make sure
the probe has
a 300
MHz bandwidth
(for
example our
model
P9020 M15xlOHF), and is perfectly adjusted,
low
frequency
and high
frequency
(see
brochure enclosed
with probe).
Turn off all
the traces
except CHI.
Trigger:
SMART
(COMPLEX)
Source:
Coupl
:
Mode:
Delay
:
Level
:
Set
the
input of CHI:
-
Coupl:
-
Gain:
-
Var:
-
Offset:
Trigger: OFF
CHI
HF
NORM
zero
zero
1 MS
AC
.1 V/div
Gain 1
zero
Set
the time base:
-
Time/div
-
Interleaved
.5
ysec/div
ON
Bandwidth
limit OFF
Adjust the
SG
503 output amplitude and
the
CHI offset
to
provide
a 5
division
p-p
sine wave.
Increase the SG 503 frequency, while
decreasing the Time/div until the
sine wave
p-p
amplitude is
.7
*
5
divisions
=
3.5 divisions
(3
dB
point)
.
12