The 250
to
500
MHz
signal
is
derived by dividing the
500
to
1000
MHz
main band signal by two.
Filtering is handled by separate low-pass filters for each frequency
band.
AM
is done using two separate modulators, one for the divide band
and one dual-output modulator for the main and heterodyne bands.
The
AM
signal from the
A3
modulation section for both modulators is
summed into the
ALC
loop integrator.
Amplitude leveling is handled with
an
ALC
loop to lock the level
and an amplitude
DAC
to set the level. The error signal from the
ALC
integrator is sent to either
of
the two modulators along with the
summed
AM
signal.
The output assembly contains
a
calibration
ROM
that contains
factory-generated calibration data that is specific to the assembly.
A7 Attenuator
The attenuator assembly contains the attenuators, the
reverse-power-protection circuitry and the temperature-sense
circuitry.
The attenuator assembly contains a calibration
ROM
that contains
factory-generated calibration data that is specific to the assembly.
Theory
of
Operation
511.5
To Next Page
Loading...
