HP 8340b User Manual

A54
YO
Pretune/Delay Compensation
Assembly
Theory
of
Operation
The
A54
YO
pretune/delay
compensation
assembly
performs
three
major
functions:
•
It
provides
a
DC
voltage
(PRETUNE)
to
the
ASS
YO
driver
that
is
proportional to
the
frequency
to
which the
YO
is
being
phase-locked.
The
YO
sensitivity
of
this
line
is
—2.5
V/GHz
(of
YO
fre¬
quency).
PRETUNE
is
also used
by
the
A28
SYTM
driver to
tune
the
A13
switched
YIG-tuned
multiplier
(located
in
the
RF
section).
•
It
generates
the
kick
pulses
that
are
necessary
at
a
YO
retrace
to eliminate
magnetic hysteresis.
These pulses
are
of
constant
amplitude,
corresponding
to
about
2.5
GHz,
and
are
of
varying
width.
The width
is
a
function
of
the
YO
start
frequency
and
sweep
width
of the
previous
sweep
as
well
as
the
YO
start
frequency
of the
next
sweep.
These
pulses
are
subtracted
from
the
phase-
lock
PRETUNE
voltage
and
temporarily
tune
the
YO
2.5
GHz
below
the
next
phase-lock
fre¬
quency.
•
It
provides
a
voltage
(VCOMP)
to
the
ASS
YO
driver
that
compensates
for
the
YO's
normal delay
at
start
of
sweep.
ASS
YO
Driver
Assembly
Theory
of
Operation
The
ASS
YO
driver
performs
the following
functions:
•
It
acts
as
a
voltage-to-current
converter
to
change
the
PRETUNE
voltage
(sensitivity
=
—2.S
V/
GHz)
to
YO
main
coil
current
(sensitivity
is
approximately
24
ma/GHz).
The
two
sensitivities
mentioned
above
are
expressed
in
terms
of
YO
frequency,
not
RF
output
frequency.
•
It
provides
the
summing
point
for
the
low
frequency
portion (<100
Hz)
of
the
YO
phase-locked
loop
error
voltage
(YO
TUNE).
•
It
provides
the
summing
point for
the
YO
delay
compensation
voltage
(VCOMP).
•
It
provides
the
summing
point for
the
YO
coil
offset
current.
•
It
provides
the
driver
circuitry
for
the
YO
retrace
kick
pulse.
HP 8340B/41B
Sweep
Generator
-
YO
Loop
Theory
of
Operation
D-13

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English