Tektronix 503, Instruction Manual

Page: 69 / 147

Calibration— Type 503
a. Test setup is shown in Fig. 6-24.
b. Connect a 50 f i termination, a UHF T connector, and
two 50-ohm cables to the output connector o f the constant-
amplitude signal generator. If desired, tw o quick-connect
adapters (item 15 o f Recommended Equipment) may be
installed at the Type 503 input ends of the cables, to per­
mit easy cable-switching,
NOTE
The tw o 5 0-ohm cables should be id e n tic a l to
assure a sym m etrical in p u t to the tw o a m p lifie rs
fo r phasing adjustm ents.
c. Connect the two cables to the VERTICAL and HORI­
ZONTAL + INPUT connectors.
d. Adjust the generator output for a 6-cm display at
a frequency of 50 kHz, and center the display exactly with
the VERTICAL and HORIZONTAL POSITION controls.
e. Change the generator frequency to 450 kHz.
f. Check—A vertical trace > 4 .2 cm in length.
g. Adjust C419 for a trace ^ 4 . 2 cm in length. See Figs.
6-25 and 6-26 for interaction of phasing adjustments.
h. Move the signal cable from the VERTICAL -f INPUT
connector to the VERTICAL — INPUT connector, change the
VERTICAL + INPUT switch to GND, the VERTICAL -IN P U T
switch to DC, and repeat steps (e), (f), and (g).
i. Change the VERTICAL —INPUT switch to GN D , and
tho HORIZONTAL -fIN PU T switch to DC. The trace w ill
now be o horizontal line.
j. Repeat steps (o), (f), and |g) for tho horizontal trace.
k. Dress the CRT deflection plate leods (instrument left
side) for a trace > 4 .2 cm in length.
l
. Chongo tho HORIZONTAL -fIN PU T switch to GND,
and the HORIZONTAL -IN P U T switch to DC.
Fig. 6 -2 6 le c a rlo n o f phasing a d |u tlm o n l C 4 I9 lin ttru m o n t lo ft
• I d o l.
m. Move the signal cable from the HORIZONTAL - f IN ­
PUT connector to the HORIZONTAL —INPUT connector.
n. Repeat tho checks as in steps (e), (f), and (g).
o. Increoso tho generator output (at 450 kHz) to display
a trace exactly 6 cm long.
p. Change the VERTICAL -IN P U T switch to DC The
trace w ill change to a straight line or flattened ellipse at
a 45* angle across the CRT screen. See Fig. 6-27 for ty p i­
cal displays.
6 - 2 2
© i
Fig. 6 -2 7 . Typical displays, a m p lifie r phasing adjustment.