Watkins-Johnson Company WJ-8718-19/FE Instruction Manual page 86

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3.2.1.2 Input RF Switching Signal Interfaces
The following input/out signals interface with the Input RF Switching
Section:
a. RF Input - Rear panel connector FE-A2J1 feeds broadband 0
to 100 MHz signals from an antenna or similar source at a 50
ohm impedance.
b. VHF Out - The VHF output is a wideband signal from 30 to
100 MHz and is sent to the Frequency Extender Section.
c. IF In - The IF input signals is 29.5 MHz +/- 1 MHz signal
received from the Frequency Extender Section.
d. RF Out - The RF output is a wideband signal from 0.005 to
30 MHz signal and is sent to the Input Conversion Section.
e. Switch Control - The Switch Control is a single control line
from the Digital Control Section and controls the routing of
RF signals within the Input Switching Section.
| 3.2.2 FREQUENCY EXTENDER SECTION
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A general description of the Frequency Extender Section functions and
signal interfaces is provided in the following paragraphs.
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3.2.2.1 Frequency Extender Section Functions
• ' The Frequency Extender Section performs the following functions:
a. Frequency Translation - VHF signals in the range of 30-100
I MHz are down converted to 29.5 MHz (2nd IF) by a double
conversion process with a 1st IF center frequency of 159.5
MHz.
b. Bandlimiting - The bandwidth of the 29.5 MHz 2nd IF output
is limited to 1 MHz.
c. Gain Control - Under high RF input signal conditions, the
overall gain of the Frequency Extender Section is reduced to
prevent overloading or saturation of succeeding receiver
stages.
3.2.2.2 Input/Output Signal Interfaces
The following input/output signals interface with the Frequency Extender
Section:
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