Changing Horizontal And Vertical Size - Tektronix 11801C User Manual

Changing Horizontal
and Vertical Size
11801C User Manual
You can change the horizontal and vertical size and position of the FFT trace
display by selecting the vertical and horizontal icons and using the knobs to
adjust size and position.
When you touch the horizontal icon (
Frequency Span/div and Frequency Resolution. The Span/div function
changes the Main Size (time base) setting (or, for windows, the Window
Size setting). The resolution function changes the record length. When you
adjust Frequency Span/div and Frequency Resolution, you are changing
the time base of the source trace, so you will see a change in the display of
all traces on that time base.
You can also use Pan/Zoom to horizontally expand the display of the FFT
trace without affecting the time base. Changing the horizontal magnification
and position of an FFT trace using Pan/Zoom changes the appearance of
the trace, but does not increase the horizontal (frequency) resolution. For
more details about Pan/Zoom, including changing the pivot point and using
multitrace Pan/Zoom, see page 3 107.
You can also change the frequency interval and frequency range by chang
ing the record length and horizontal size of the time domain trace. If the
record length increases, frequency resolution improves (dF decreases).
When the effective sample rate increases (due to a faster horizontal size
setting), F and dF both increase, giving the FFT trace a broader frequen
max
cy range with less frequency resolution.
When you touch the vertical icon ( ), the knobs are assigned to control
Vertical Mag: Tra and Vertical Pos: Tra, the vertical magnitude and position
of the trace. As with other calculated traces, the vertical controls of the FFT
trace affect only the appearance of the trace.
Fast Fourier Transforms
), the knobs are assigned to control
3 69