Philips PM 5715 - Page 52

9.
Calibration
SURVEY
OF
CALIBRATION
POINTS
AND
REQUIRED
TEST
INSTRUMENTS
Calibration
Calibration
Refer
to
point
paragraph
R313
+
22.5V
A
R502
Start
oscillator
B
R226
Trailing
ramp
C
R258
Pulse
amplitude
C
R261
Pulse
amplitude
C
C226
Pulse
shape
C
C229
Pulse
shape
C
OSCILLATOR
1.
Set
the
PM
5715
controls as follows:
REP.
TIME
20ns
VERNIER
fully clockwise
2.
Connect
the SYNC.
OUT output
to the
oscilloscope
via 20dB
attenuator
3.
Set
the trimmer R502
on
unit PM
5715-1
until
the oscillator runs
properly
4.
Rotate
the rep. time VERNIER
fully
counter-clockwise
5.
Check
that the
oscillator
runs properly.
If
not, readjust
R502
and repeat
steps
3
through 5
C. OUTPUT
CIRCUIT,
UNIT
PM
5715-2
Test instruments
and devices
For
calibration
of R313 use:
Digital
voltmeter,
e.g.
PHILIPS
PM2421
For calibration
of R502...C229
use:
Sampling
oscilloscope,
e.g.
PHILIPS
PM3400
20dB
attenuator,
50Q
A.
POWER
SUPPLY,
UNIT
5715-3
GENERAL
Allow
the
PM
5715
to
warm
up for
at least 10
minutes before
calibrating.
The voltages
men-
tioned
apply
at nominal
mains voltage.
EQUIPMENT REQUIRED
-
Digital
voltmeter,
e.g. PHILIPS
PM 2421
+
22.5V
1. Connect
the DVM
to terminal BU309
on the power
supply
unit
PM
5715-3
2.
Set trimmer
R313
until
the
DVM
reads
+
22.5V±1 %
3.
Check
that
the voltage
at terminal
BU307
is
-22.5V±1
%
4.
Check
that the voltage
at
terminal
BU310
is +6V±1 %
B.
TIMING CIRCUIT,
UNIT PM
5715-1
EQUIPMENT REQUIRED
-Sampling
oscilloscope PM 3400
-50Q
attenuator,
20dB
EQUIPMENT REQUIRED
-Sampling
oscilloscope, PM 3400
-50Q
attenuator, 20dB
PM 571
5 as
follow:
1
ps
fully counter clockwise
PRQCEDURE
1
.
Set
the
controls of
REP.
TIME
VERNIER
T/2 mode
?T
^
f?
T!
_|_
TT
NQRM/INV.
NORMAL
DC OFFSET OV
AMPLITUDE
5V
VERNIER
fully clockwise
RAMP TIME
6ns
tr, tf
fully counter-clockwise
2.
Connect
the sampling
oscilloscope
to
PULSE
OUT via 20dB
attenuator
3.
Set
R226, R258
and R261
to mid-position
4.
Set
C226 and
C229 to minimum
capacitance
5.
Adjust
R261 until
pulse
amplitude is
+5.5V
6.
Turn
vernier tf fully
clockwise
7.
Adjust
R226 until
td2 is
40ns (refer
to
Fig.
9-1)
8.
Repeat
steps
5,
6
and
7
9.
Turn vernier
tr fully
clockwise
and check
that tdl
<25ns (refer
to
Fig.
9
-
1
)
10.
Set switch
"
±
"
to
"
—
"
11.
Adjust
R258 until
pulse
amplitude is
-5.5V
12.
Turn vernier
tr
and tf fully
clockwise
and
check that
td3 is
<25ns and
td4 is
<40ns
(Fig.
9-2)
13.
Set
vernier tr
and tf fully
counter-clockwise.
Adjust
trimmer
C226 until
output
pulse
has
no
overshoot or
rounding (refer
to
Fig.
9
—
3)
14.
Set switch
"
±
"
to
"
+
"
15.
Adjust
C229 until
output pulse
has no
over-
shoot or rounding
(refer
to
Fig.
9
—
4)