struments to the internally generated pulse; the
video pulse is a TTL level copy of the RF output
pulse; and the sample/hold signal synchronizes the
ALC loop to the ON portion of the pulse modulating
waveform.
The 682XXB/683XXB has five pulse modulation
modes:
Internal pulse modulation mode – The pulse
modulation waveform is generated and timed
internally.
External pulse mode – The external pulse
source signal from the front or rear panel con-
nectors is interfaced by the pulse generator to
the pulse modulation driver.
External triggered mode – The pulse generator
is triggered by the external pulse source signal
to produce the pulse modulation waveform.
External gated mode – The external pulse
source signal gates the internal pulse genera-
tor on and off.
Composite mode – The external pulse source
signal triggers the internal pulse generator
and also modulates the RF output signal. The
pulse generator produces a delayed, single
pulse waveform that also modulates the RF
output signal.
2-5 RF DECK ASSEMBLIES The primary purpose of the RF deck assembly is to generate CW and
swept frequency RF signals and route these signals to the front panel
RF OUTPUT connector.It is capable of generating RF signals in the
frequency range of 0.01 to 65 GHz.
The series 682XXB/683XXB synthesized signal generators use a single
2 to 20 GHz YIG-tuned oscillator.All other frequencies are derived
from the fundamental frequencies generated by this oscillator,as fol-
lows:
RF output frequencies of 0.01 to 2 GHz are developed by down-
converting the fundamental frequencies of 6.51 to 8.5 GHz.
RF output frequencies of 0.5 to 2.2 GHz are developed by down-
converting the fundamental frequencies of 2 to 4.4 GHz.
RF output frequencies of 20 to 40 GHz are produced by doubling
the fundamental frequencies of 10 to 20 GHz.
RF output frequencies of 40 to 65 GHz are produced by quadru-
pling the fundamental frequencies of 10 to 16.25 GHz.
The following paragraphs briefly describe the operation of the RF deck
assembly.

682XXB/683XXB MM 2-19

FUNCTIONAL RF DECK
DESCRIPTION ASSEMBLIES