Tektronix 7B70 Time Base Instruction Manual page 21

Operating Instructions-7B70 (SN B205000 and Up)
Second-vertical Tenth-vertical
Fig.
2-8.
Area of graticule used for accurate time measurements.
able sweep rate range from 20 nanoseconds/division (from
2 nanoseconds/division with MAGNIFIER at X10) to about
12.5 seconds/division.
( A ) Unmagnified Waveform
-
-
(B) Magnified Waveform
When making time measurements from the graticule, the
area between the second-division and tenth-division vertical
lines of the graticule provides the most linear time measure-
ment (see Fig. 2-8). Therefore, the first and last division of
the display area should not be used when making accurate
time measurements. Position the start of the timing area to
the second vertical line (second line from the left) and
adjust the 1-IWIEIDIV switch so the end of the timing area
falls between the second-division and tenth-division vertical
lines.
Fig.
2-9.
Operation of sweep magnifier.
Sweep Magnifier
10. For example, if the TIMEIDIV switch is set to .05 ps,
the equivalent magnified sweep rate is 5 nanoseconds1
The sweep magnifier
the sweep
ten times' The
division. The eqLlivalent magnified sweep
rate must
be used
center division of the unmagnified display is the portion
for all
time measurements when the XIO-MAG,,,I FIER
visible on the screen in magnified form (see Fig. 2-9).
button is lighted. The equivalent magnified sweep rate is
Equivalent length of the magnified sweep is more than 100
divisions; any 10-division portion can be viewed by ad-
calibrated when the VARIABLE TIMEIDIV control is in
the calibrated position.
justing the horizontal POSITION control to bring the
desired portion onto the viewing area. The dual-range
feature of the horizontal POSITION control is particularly
useful when the MAGNl Fl ER is set to XlO (see Horizontal
Position Control discussion which follows).
To use sweep magnification, first move the portion of
the display which is to be expanded to the center of the
graticule. Then press the X 10-MAGN I FI ER pushbutton;
the X I 0 button lights to indicate that the horizontal sweep
rate i s magnified. Whenever the X I 0-MAGNI FIER push-
button is lighted, the equivalent magnified sweep rate can
be determined by dividing the TIMEIDIV switch setting by
Horizontal Position Control
The 7B70 provides both fine and coarse adjustment of
positioning. The coarse adjustment provides rapid horizon-
tal positioning of the trace. Fine positioning is provided for
more precise control of trace position.
Display Mode
Time-Base. With the DISPLAY MODE switch in the
TIME BASE position the 7B70 functions a s a normal time-
base with the sweep rate set by the TIMEIDIV switch.
Scans by ArtekMedia O 2006