HP 8340b User Manual

A59
DIGITAL
INTERFACE ASSEMBLY
The
digital
interface
links
the
instrument
processor
to
the
sweep
generator,
the
reference
M/N
oscillator, and
the
20-30
synthesizer.
Read/Write
Strobes
The
instrument
processor
read/write
strobes enable
buffers
that
either
send data
to
the
instrument
processor, or
clock
registers
that
store
data
sent from
the
instrument
processor.
Several strobes
also
operate registers
on
other
assemblies.
Low
Stop
(LSTP)
and
Low Service
Request
(LSRQ)
The
digital
interface
assembly connects
to
the
16-bit
data
bus
(DBO
to
DB15). Using
the
LSTP
(low
stop) signal,
this
assembly
can
stop
all
instrument
processor
operations
when
all
current
tasks
are
completed.
When
the
instrument
processor
stops,
the
RUN
LED
on
the
processor
assembly
turns
off.
LSTP
stops
the
instrument
processor when
it
is
not
needed,
or when
it
is
necessary
to
eliminate
all
potential
sources
of
digital
noise
(e.g.
during
forward
sweeps).
When
the
LSTP
signal
releases
the
instrument
processor
to
perform
a
task,
the
instrument
processor
defers processing
until
it
determines
that
the
LSRQ
(low
service
request)
signal
is
low.
LSRQ
can
be
sent
low
by
the
digital
interface,
by
the
front panel
interface, or
by
LBX
(low
bandcross).
Once
LSRQ
is
sensed
low,
it
can go
high
again;
the
instrument
processor
finishes
all
pending
tasks
before
checking
this
signal
again.
Controller
Response
Using
the
change
detectors and
the
processor
service
request
block,
the
instrument
processor
responds
to
the
Following:
•
Changes
in
the
UNLOCK
or
OVEN
indicators
•
Changes
in
OVERMOD
or
UNLEVELED
conditions
•
Changes
in
the
EXTERNAL
REFERENCE
switch
position
•
Sweep
events
as
indicated
by
the
marker/bandcross
assembly
The instrument
processor
also distinguishes
between
power
on
and
instrument
preset.
F-4
Controller
Section
Theory
of
Operation
HP
8340B/41B

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English