HP 4262A User Manual

Extender
RAM.
When
data
is
transferred
to
the
RAM,
the
DSW
signal
actuates
the
RAM
and
the
Address
Register
addresses
the
RAM
to
assign
individual
memories
for
storing
the
data.
When
a
DSR
signal
actuates
the
RAM,
the
Nanoprocessor
causes
the
RAM
to
output
stored
data.
The
RAM
writes
out
data
as
addressed
by
signals
inputted
at
the
RAM
ADDRESS
signal
port.
The
clock
pulse
generator
oscillates
at
2.54MHz
and
is
frequency
stabilized
by
a
crystal
resonator.
Divider
U12
counts
down
the
2.54MHz
basic
clock
by
one
half
(to
1.27MHz)
and
provides
the
nano-
processor
with
a
stable
time
base
for
synchronizing
various
circuit
timing.
The
Down
Counter
(U7,
U14
and
U15)
produces
the
31.83kHz
frequency
whose
value
coincides
with
the
reciprocal
number
of
pi
(m
=
3.14159---).
This
particular
frequency
is
significant
in
derivation
of
the
measured
value.
The
secondary
clock
signal
is
fed
to
the
Nanoprocessor
for
calculating
the
value
of
the
DUT.
Additionally,
the
Down
Counter
drives
the
Scan
Counter
(U2)
which
produces
display
timing
signals.
8-33. A2 DISPLAY AND KEYBOARD.
A2 section includes the Keyboard Control, Dis-
plays, and certain decoders. The Keyboard Control
manipulates the Keyboard Scan signals sent from
the Scan Decoder (U4) and outputs the resulting
CLM (CoLuMn) signals. All annunciator data
except for alphabetic annunciations are trans-
mitted from the A21 section. Because the range
and multiplier annunciator data has been coded to
minimum bit size, the Decoder Drivers U3 and U4
translate them so as to illuminate proper indicators.
The Unit and DQ annunciator signals are fed,
respectively, via the Function and Loss indicators
assembled in the keyboard pushbutton. The
;‘ numeric displays are independently driven by the
. A22 section.

HP 4262A Specifications

General

Brand	HP
Model	4262A
Category	Measuring Instruments
Language	English