Tektronix P6015 - Page 9

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. C2—Set fully clockwise and back off 2 turns.
R2—Set fully clockwise and back off 90 degrees.
2. Adjust R5 for exactly 2 major divisions of vertical
deflection on the crt. Use the level portions of the square
wave if the waveform is over- or under-peaked.
3. Set the sweep rates for 50 us/div and display the
leading corner of the square wave. Adjust R1, C3, and C1
for the sharpest leading corner without overshoot (see Fig.
2-1). Each may have to be adjusted several times for the
sharpest corner. Maintain 2 divisions of deflection at the
leading edge. The R1-C3 combination affects the very
corner and C1 affects the area immediately following with
some overlap.
4. Set the sweep rate of the oscilloscope for 0.2:ms/div
and adjust R2 and C2 to level the trailing 2 divisions of the
top of the square wave.
| 5. Set sweep for 0.2 ms/div. Adjust C3 and C1 for a flat
top on the square wave.
6. Any remaining aberrations may be corrected by slight
readjustment of C1, R2, €2, R1, and C3.
Fig. 2-1. Pulse area affected by each compensation adjustment.
The preceding steps da not include high-frequency
peaking adjustment R3. The affect of R3 is apparent only
with risetimes faster than about 0.1 microsecond. Conse-
quently, the calibrator signal is not fast enough for this
adjustment. The most desirable signal source is a fast-rise
pulse generator with enough charge line to generate at least
a 100 ns pulse. However the 1 MHz output of a Tektronix
Square Wave Generator terminated in 50 ohms is also
adequate. With any of these generators, it is advantageous
to have a plug-in unit with a sensitivity greater than 0.05
volt/div, such as the Tektronix 7A13. R3 should be
2-2 Operating Instructions—P6015