Tektronix 492 Operator's Handbook

calibrated for each FREQ SPAN / DIV selection . The AUTO
position of the
TIME
/ DIV
selector ties the
sweep speed to
the analyzer span / div and resolution bandwidth . The
AUTO mode
of the
RESOLUTION
BANDWIDTH op
timizes bandwidth for the selected FREQ SPAN / DIV and
TIME / DIV settings unless either is outside the range of
correction . When this occurs , the UNCAL indicator lights
and a " > " symbol prefixes the REF Level readout on the crt
display
.
When analyzing pulse signals , a wider bandwidth than
that provided by AUTO is usually desired . The resolution
bandwidth should be on the order of 1/10 the side lobe
frequency width , or the reciprocal of the pulse width , in
order to ensure adequate resolution . The RESOLUTION
BANDWIDTH is usually set for optimum main lobe detail
after the sweep rate has been selected .
USING THE PEAKING CONTROL
The PEAKING control adjusts bias for the EXT MIXER
port and the preselector tracking for the instruments with
Option 1. It is adjusted for maximum conversion or
maximum signal amplitude . This control has a marked
effect on performance when operating in the higher
frequency ranges . Mixer peaking when Option 1 is
installed , must be adjusted before relative amplitude and
sensitivity measurements are made when operating above
Band 1 ( 1.8 GHz ) . Frequency response and flatness are
also
affected ;
therefore
,
after any
significant
frequency
change , it is good practice to degauss , then adjust
PEAKING for
maximum
signal
amplitude .
Degauss with
FREQ SPAN / DIV of 2 MHz or 1 MHz .
USING THE SIGNAL IDENTIFIER
Conversion
in
the 1st mixer
generates
many
spurious
responses .
This is due
to the
multiple
harmonics of the
local oscillator converting input signals to an intermediate
frequency within the bandpass of the IF . This is especially
true for the basic 492 ( without the Option 1 preselector )
and when the waveguide mixers are used .
To
help
identify true
signals , the 492
features an
' identify ' mode . With the FREQ SPAN / DIV at 500 kHz ,
press the IDENTIFY 500 kHz / ONLY button . True signals
will alternately shift vertically while spurious signals shift
horizontally or off screen . Identify mode will operate only
when the frequency span is 500 kHz / div .
492
Operator's
Handbook
3-3

Tektronix 492 Specifications

General

Brand	Tektronix
Model	492
Category	Measuring Instruments
Language	English