TM 11-6625-3059-10
USING EXTERNAL OSCILLATOR (EXT OSC)
External Local Oscillator (EXT OSC)(LO) Measurements
A connector is provided on the rear panel for application of an external local oscillator signal. The external
oscillator frequency is determined from the following formula:
f
LO = (f + 1)/n
where f = signal frequency in MHz
n = any integer which allows
f
LO to fall between 10
and 20 MHz.
USING EXTERNAL OSCILLATOR (EXT OSC)
Example: For a signal frequency of 100 MHz
f
LO = (100+ 1)/n = (101)/n
For n = 10, fLO = 10.10 MHz
n = 9, fLO = 11.22MHz
n = 8, fLO = 12.635 MHz
f
n = 7, LO = 14.428 MHz
n = 6, fLO = 16.83 MHz
Any of the above listed local oscillator frequencies at a level of + 10.0 dBm may be used to produce the proper if.
The highest possible local oscillator frequency is generally used; however, for applications where a synthesizer
type generator is used as the local oscillator signal source, it may be useful to note that a lock point will always
exist between 10 and 13 MHz for rf signals above 40 MHz.
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