Advertisement
Model 8902A
Operation
Ratio and Log/Lin
FUNCTIONS
RATIO, PREVIOUS RATIO, LOG/LIN, Special Function
1 1
(Previous Ratio)
DESCRIPTION
T h e Ratio and Previous Ratio fiinctions permit any measurement result to be scaled to a reference.
T h e reference may be either a measurement result o r a keyboard entry. Special Function I 1.2 displays
the current ratio reference.
T h e LOGILIN
k e y
enables measurement results to be displayed in linear o r logarithmic units, both
absolute and relative. Examples of absolute units are kHz and mV (linear), o r dBm (logarithmic).
Examples of relative units are
O / O
and dB. For purposes of discussion, basic measurement units, such
as
Yo for AM
o r
distortion, dB for SINAD, etc., (though actually relative units), are treated as absolute
units. When the instrument displays
O/o
and dB as relative units (that is, when the ratio function is
used), annunciator R E L is added to the display.
All modulation and all frequency measurement results cannot be displayed with absolute, logarithmic
units even though they can be displayed in relative, logarithmic units. (The LOG/LIN key is ignored.)
T h e Ratio function can be used with the following measurements:
AM
SlNAD (29.0 SPCL)
F M
9 M
LO Frequency (33.0 SPCL)
R F POWER
FR EQ
AUDIO FREQ
AUDIO DISTN
I F LEVEL
TUNED RF LEVEL
F R E Q ERROR
Ext Audio RMS Level (30.0 SPCL)
I F Frequency (34.0 SPCL)
R F Level (35.0 SPCL)
Peak Tuned R F Level (36.0 SPCL)
T h e Ratio fiinc!ion is exited when:
0
the RATIO key is pressed a second time,
0
a new measurement is selected, or
0
other measurement units are selected.
PROCEDURE
Select LOG/LIN anytime during a measurement t o change the display between linear and logarithmic
units, where permitted. for both absolute and relative (Ratio) displays.
To use the Ratio function:
in "DESCRIPTION."
1. Select the desired Measurement mode. Measurements possible with the ratio fiinction are listed
3-245
Advertisement
Chapters
