Fig. 6-38. Equipment setup to adjust wide band IF amplifier and check flatness.
Type 491 FINE RF CENTER FREQ
Centered
INTENSITY
FOCUS and ASTIGMATISM
SCALE ILLUM
POSITION (Horizontal and
Vertical]
TIME/DIV
VARIABLE
TRIGGER
SLOPE
LEVEL
SOURCE
DISPERSION RANGE
DISPERSION-COUPLED
RESOLUTION
IF ATTENUATOR dB
IF CENTER FREQ Controls
VIDEO FILTER
VERTICAL DISPLAY
GAIN
POWER
MIXER PEAKING
PHASE LOCK Controls
Display of nominal
brightness
INT REF FREQ
ON
Adjusted for optimum
Test Oscilloscope
display definition.
Time/Cm 1 ms
As desired
Volts/Cm
.005
Adjusted for a horizon-
Input Coupling
AC
tally centered sweep on
Trigger
Int
the graticule baseline
20 ms
CAL
+
FREE RUN
INT
MHz/DIV
5 MHz/DIV
20 dB switch on
Midrange (000)
OFF
LIN
Midrange
ON
Manual
36. Adjust the Wide Band Amplifier
o
Response and Check the System Response
Flatness
NOTE
The Type 491 response flatness and sensitivity
is dependent on the combined response of the
wide band amplifier, the bandpass filter, the low
pass filters and the RF mixer. Each circuit assem-
bly must be adjusted as part of the complete
system, since the circuit response for each unit is
dependent on the impedance presented by the
preceding and following circuit.
The low-pass and bandpass filters should require
recalibration only after circuit components have
been replaced.
If recalibration is required, the
analyzer should be returned to Tektronix for cali-
6-36
To Next Page
Loading...
