Tektronix 2445, Instruction Manual

Page: 108 / 351

Performance Check— 2445 Service
b. Select 5 ns time markers from the Time-Mark Genera­
tor and adjust the TRIGGER LEVEL control for a stable
display.
c. Use the Horizontal POSITION control to align the 2nd
time marker with the 2nd vertical graticule line (2nd from the
left edge of the display).
NO TE
The 2 ns and the 5 ns time markers are sinusodial.
Use either the rising or falling zero-crossings as align­
m ent points.
d. Align the AREF cursor with the 2nd time marker and
align the A cursor with the 10th time marker.
e. CHECK—The A Sweep timing and cursor readout
accuracies are within the limits given in Tables 4-6 and 4-7.
N O TE
If the 2nd and 10th time m arkers are within ± 0 .0 6
division o f the 2nd and 10th vertical graticule lines for
unmagnified sweeps and within ± 0 . 1 division for
magnified sweeps, the sweep timing accuracy is con­
servatively within limits. When the timing accuracy is
checked a t each sweep speed, note any S E C /D iV set­
ting a t which the timing error exceeds the 0.6-division
limit. Check these sweep speeds against the major-
division tim e-interval limits given in Table 4-7.
NO TE
For A and B S E C /D IV switch settings o f 10 ns, the
tim e-m arker period is greater than 1 division when the
sweep is magnified. A t 1 ns p er division, 1 ns p er divi­
sion (S E C /D IV setting o f 10 ns with X I 0 MAG), check
for 4 cycles between the 2nd and 10th vertical grati­
cule lines ( ± 0 . 1 division).
f. Repeat parts c, d, and e for each A SEC/DIV-time
marker combination given in Table 4-6 for both unmagnified
and magnified sweeps.
4-19