Tektronix 543B Instruction Manual page 36

Calibration — Type 543B /R M 543B
area. Again, be sure that the front corner does not begin
to tilt up or down.
With the TIME/CM switch at .2 /iSEC, adjust C568 for mini­
mum ringing on the front corner area of the wavfeorm.
Some of the high-frequency adjustments just made may
affect the vertical gain. It is therefore necessary to check
the vertical gain. Refer to step 6 for gain setting instructions.
26. Checking Risetime
With all controls left as in step 25, set the HORIZONTAL
DISPLAY switch to X 5 SWEEP MAGNIFIED.
magnifier on and the TIME/CM control set to .1 ,uSEC each
centimeter of horizontal deflection on the graticule rep­
resents 20 nsec.
Adjust the TU-7 Amplitude control for a display amplitude
of 5 cm. Using the Vertical Position control, place the top
of the display on the long dash line which is at the 2'/j cm
point above the center graticule line. The bottom of the
display should now be on the long dash line 2Vz crn below
the center graticule line.
With the HORIZONTAL POSITION control, move the
point at which the lower part of the waveform crosses the
small dash line, to a point near the center of the graticule
where a horizontal and vertical graticule line intersect (see
Fig. 5-7). Now using the above intersection as the starting
point (10% point) follow the vertical graticule line up to
the small dash line, then follow the small dash line to the
right until it intersects the waveform. This is the 90% point
of the waveform. The distance from the vertical graticule
line to the intersection of the small dash and waveform
times 20 nsec gives the risetime of the waveform. The rise­
time should be less than 10 nsec. Refer to Fig. 5-7.
Turn the TRIGGER SLOPE to —INT and the Test Function
switch to —Pulse. To measure the risetime of a negative
pulse, use the same technique as described previously. The
exception is ihct the top part of the pulse is lined up with
an intersection of a horizontal and vertical graticule line
to establish the starting point (10% point).
graticule line is then followed down and to the right to find
the 90% point. The normal specified risetime for the posi­
With the
tive and negative pulses is the same.
The vertical