USING EXTERNAL OSCILLATOR (EXT OSC)

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:

LO = (f + 1)/n

where f = signal frequency in MHz

n = any integer which allows

LO to fall between 10

and 20 MHz.

USING EXTERNAL OSCILLATOR (EXT OSC)

Example: For a signal frequency of 100 MHz

LO = (100+ 1)/n = (101)/n

For n = 10, fLO = 10.10 MHz

n = 9, fLO = 11.22MHz

n = 8, fLO = 12.635 MHz

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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