Philips pm3232 - Page 38

80
—
Check that no
overshoot is visible
(maximum pulse
top
errors 2
%)
and also check the trace
height;
If
necessary, correct the
pulse
top
errors
with the aid
of
the
trimmers
(Fig.
3.14.)
mentioned
in the following
table
Position
AMPL
switch
SK17
(78)
Signal
to
Yfy
(Ygl
BUS
(5)
Adjust
with
Trace
height
2 mV/cm
12 mV
C52 (C252)
6cm
+
or
—
2 %
5
mV/cm
30
mV
C52 (C252)
6
cm
+
or
—
2 %
10 mV/cm
60
mV
C52 (C252)
6
cm
+
or
—
2 %
20
mV/cm
120
mV
C52
(C252)
6
cm
+
or
—
2 %
50
mV/cm
300 mV
C52
(C252)
6cm
+
or
—
2 %
.
1 V/cm
600 mV
C52 (C252)
6cm
+
or
—
2 %
.2
V/cm
1.2
V C28 (C228)
6cm
+
or
—
2 %
.5
V/cm
3 V
C28 (C228)
6
cm
+
or
—
2
%
1 V/cm 6 V C28 (C228)
6cm
+
or
—
2 %
2 V/cm
12
V
C33 (C233)
6cm
+
or
—
2 %
5
V/cm
30 V
C33
(C233)
6cm
+
or
—
2 %
10 V/cm
60 V C33 (C233)
6
cm
+
or
—
2
%
—
Set
AMPL
switches
SK17
and SK18 to .1
V/cm
—
Apply
a
square-wave voltage of 1.2
Vp.p, repetition
rate 10
kHz, rise time not
exceeding
200 ns,
to
input
socket
BUS via a
2:
1 dummy
measuring probe
consisting
of
a
1 MOhm
resistor and a
30
pF
trimmer
in
parallel.
If higher voltages are
available, a
10:1 attenuator
probe may be
used.
—
Adjust the
trimmer
of
the
dummy probe
for
optimum
square-wave
response.
—
Apply
the input
signal via
the dummy probe to
Yb
input
socket
BU5
—
Check that the top
of
the
displayed
pulse is straight;
if
necessary,
readjust
trimmer C235
(Fig.
3.14.)
“
Connect,
via
the dummy
probe,
a
square-wave
voltage
with an
amplitude as
indicated
in the
following
table,
a
repetition
rate
of
10 kHz and a rise
time not
exceeding
200
ns
to
Y/\
(Yq) input
socket
BUS
(BUB)
—
Check that
neither overshoot
nor rounding
is visible
(maximum
pulse
top
errors
3
%)
and
also
check
the
trace
height;
if necessary,
correct the
pulse top
errors
with the aid
of
the
trimmers
(Fig.
3.14.)
mentioned
in the
following
table
Position
AMPL
Signal to
2:
1
dummy
Adjust
with
Trace
height
switch SK17
(18)
.2
V/cm
2.4 V C29 (C229)
6
cm
+
or
-
2
%
.5
V/cm
6
V
C29 (C229)
6
cm
+
or
-
2 %
1 V/cm
12 V
C29
(C229)
6cm
+
or
—
2 %
2 V/cm
24
V
C34 (C234)
6cm
+
or
—
2
%
5
V/cm
60
V
C34 (C234)
6cm
+
or
—
2 %
10
V/cm
60
V
C34 (C234)
3
cm
+
or
—
3 %
3.2.4.7.
Square-wave
response
(C62, C262,
R113, R313)
-
Depress
Ya
(Yq) switch
SK4 (SK5),
AUTO
switch SK10
and BEAM
SELECTOR
switch
A SK14
(B
SK15)
-
Set
TIME/cm
switch
SK2
to
.2
jus and TIME/cm
potentiometer R2 to
CAL
-
Set
AMPL switch SK17 (SK18)
to
.1 V/cm and
AMPL
potentiometer R4
(R5)
to
CAL
-
Set
AC-O-DC
switch
SK16
(SK19)
to AC
—
Apply a
square-wave
voltage
of 600
mV,
repetition rate
1 MHz, rise
time
1 ns
—
Check the
square-wave
response.
The pulse top
errors must
not exceed 2
%;
if
necessary,
readjust
trimmer
C62 (C262)
or
select a
different value
for resistor R1
13
(R313)
-
Set AMPL
switch SK17
(SK18) to
.2
mV/cm
—
Decrease
the input
voltage
to 12
mV
—
Check that
the
pulse top
errors
do not
exceed
2
%
(a
slight rounding
is
permissible)