Tektronix 492 Operator's Handbook

14
15
2-6
DEGAUSS . When the DEGAUSS button is
pressed , current through the tuning coils of the
YIG oscillator ( 1st LO ) and YIG preselector
( when installed ) is reduced to zero to minimize
hysteresis effects . This enhances center
frequency and display amplitude accuracy .
DEGAUSS does not function when the FREQ
SPAN / DIV
is less than
1 MHz / Div
.
Degauss the
tuning coils after a significant frequency change
and before calibrating the center frequency
readout .
IDENTIFY 500 kHz ONLY . Signal identify feature
is
functional
only when
the FREQ
SPAN / DIV is
500 kHz . When activated ( button lit ) true signals
will change amplitude each sweep ; images and
spurious response signals will shift horizontally
or off screen . To ensure that the signal is
changing
amplitude every
sweep
,
decrease the
sweep rate so each sweep can be analyzed ; or , if
the instrument has digital storage , activate SAVE
A
,
VIEW B.
When the true signal is centered under the dot
marker after degauss , the FREQUENCY readout
is the signal frequency ( within specification ) .
Degauss
by
pressing
DEGAUSS
at
FREQ
SPAN / DIV setting of 1 MHz or 2 MHz .
16
PHASE LOCK
( Option 3 ) . The
1st LO is locked
to
a stable internal reference and the 2nd LO swept
to reduce residual FM in narrow spans ; the button
lights when phase lock is active . In narrow spans
phase lock
can be
turned off
or back
on by
pressing
the
button .
Spans for
which the
microcomputer
automatically
selects
phase
lock
are
:
Band
1
, 2 ,
3
4
5 and above
492
Operator's
Handbook
Span
/
Div
50
kHz and
below
100
kHz and
below
200
kHz and
below
17
AUTO RESOLUTION . This is a pushbutton that
activates automatic bandwidth selection for the
selected FREQ SPAN / DIV and TIME / DIV and
VIDEO FILTER . An internal microcomputer
selects bandwidth to maintain a calibrated
display . When the TIME / DIV is in AUTO mode ,
resolution bandwidth becomes a function of the
FREQ SPAN / DIV selection .
@

Tektronix 492 Specifications

General

Brand	Tektronix
Model	492
Category	Measuring Instruments
Language	English