TB 9-4931-523-35
LO = (RF -IF)/2
Where:
RF = frequency of signal generator No. 1 above
IF = intermediate frequency at which receiver system is to perform measurement (0.700 GHz).
EXAMPLE
Let IF =
0.700
Let RF =
18 GHz (1) above
Let LO =
LO
=
(RF -IF)/2
LO
=
(18 GHz -0.700 GHz)/2
LO
=
17.3 GHz/2
LO
=
8.65 GHz
(3) Adjust signal generator No. 2 frequency controls to value determined in (2)
above and RF output controls to +8 dBm.
NOTE
Use adapters as needed.
NOTE
Use waveguide-to-coaxial adapters when TI is coaxial.
(5) Establish a reference on receiver system at 0.700 GHz.
(6) Insert TI between POINTS A and B (fig. 2).
NOTE
Ensure receiver system is in measurement mode.
(7) Measure and record receiver system indication. Measured attenuation will be
within the range and accuracies listed in appendix for TI being calibrated.
(8) Repeat (1) through (7) above for remaining test frequencies recorded in 7a
above.
b. Adjustments. No adjustments can be made; however, a corrective chart may be
prepared showing actual attenuation value at frequencies of interest.
11. Variable Attenuation
Measurement (18 to
26.5 GHz)
a. Performance Check
(1) Adjust signal generator No. 1 frequency controls to value (RF) recorded in 7a
above and RF LEVEL output control for +3 dBm.