Giga-tronics 8003, Operation Manual

Page: 121 / 258

Operation
Manual 20791, Rev. C, June 2001 2-85
All of the scaling functions of the analyzer can be found under the
[SCALE]
key. Each channel can be
scaled independently, so the proper channel button must be pressed to make it the active entry channel
before scaling. To scale a channel, press
[SCALE]
to bring up the scaling softkey menu on the display.
The displayed trace vertical characteristics are dependent on three settings - the SCALE factor, the
REFerence POSition, and the REFerence LEVEL.
The easiest way to scale a trace is with the [ AUTO SCALE ] softkey. When you press this key, the
analyzer will automatically scale the trace so that it fills the screen and is centered vertically. When
autoscaling, the analyzer only changes the SCALE factor and REF LEVEL. Their new values can be read
from the status section for the active channel.
Sometimes you will want to manually change the vertical characteristics of the display. To do this, you
will use the [
SCALE FACTOR ], [ REF LEVEL ] and [ REF POS ] softkeys.
The [ SCALE FACTOR ] softkey allows you to change the scale factor per division (in dB/division) with
either the spin knob or the number pad. The scale factor setting is displayed in the lower left area of the
status section for each channel.
The [ REF LEVEL ] softkey allows you to specify the level for the reference line. The reference line is the
level on the screen which remains fixed during scaling. In other words, all points on the trace are scaled
from that fixed level. The REF LEVEL value can be changed by either the spin knob or a number pad
entry. This value is displayed in the lower right area of the status section for each channel.
The [ REF POS ] softkey allows you to change the graticule position on the screen of the reference line.
The REF POS can only be changed by the spin knob, not by the number pad. The graticule position of
the reference line is indicated by a small number on the left hand side of the grid corresponding to the
channel number.
Figure 2-40: SCALE Display & Softkey Menu Typical Display
Scale Factor
Readout Area
Ref Position
Readout Area
Ref Level Readout Area
REF
POSN
COUNT
AUTOSCL
AUTO-
SCALE
SCALE
FACTOR
REF
LEVEL
SCALE
STRT 2.000 GHz CRSR 6.204 GHz
STOP 10.000 GHz
CH1 : SW A -PC -8.48 dB
0.1 Db / REF 0.00 dB
SCALE FACTOR
0.1 dB/DIV
1
CH1: PASS