HP 8110A Service Manual page 238

5-Wi dth Ge nerator
Thi s section sets t he wi dth
o
f
t he O utpu t pulse
6-Sl ope Ge n erator
Thi s circuitry p rodu ces t he
l ead ing and tra ilin g
edge sl op es of the output wa veform
7-S lo p e C u rrents
Thi s circui tr y contro l s the S lope Ge ne rator
p
erform an ce
8- Vari able Ampli tude Gen erator
Thi s circuitry co ntrol s t he amp lit ude o f t h e out put
wa v e form
9- Vern i er C u rren ts
Thi s circuitry pro vides curren t
f or the Var iable
Ampli t ude Gen erator
10-O u t pu t Co n trol
Thi s section sets th e output con dit ions an d th e
relati onship b et ween the t wo ch annel s, wh en α
secon d channel i s fitted
11-Offset Ge n erator
Thi s sets t he offset voltage
f
or the out pu t
waveform
12-O utput Enabl e and
P rotect ion
Thi s circ ui try enables the out put wh e n conditio n s
are correct, an d
p
rotects th e outpu t fro m damage
whe n the y are not .
More detailed descrip t ion s o f
t
he funct ional un its
f oll o w :
Power
F
ilters
This sect ion i s on sc hem at ic 6Α.
HP 8110 Α Service Guide
Th e
P
o wer S upplies to t he Output B oard are fil tered for
n oi se and
addi ti o n al voltages are ge nerated .
U 1
p rovi des +15
V
f rom the +32V lin e
f or supplying Op-amps.
U 3
p
rovi des -15 V from the -32V lin e
f or supplying Op-amps.
Selftest and A
dju
st DAC
Thi s sectio n i s on schem at ic 6C .
U
2
p rovi des α
p
recise +5V reference, a nd -5 V refere nce is derived
from
t hi s by U100A
a
n d associated comp onents .
At switch-on the Se lftest sect ion
c
heck s t hat th e Microprocessor is
w or king . If t he Mi croprocessor is OK no error
m
essage
i s displ ayed .
Α co mpl ete selftest i s
p erformed when requested
f rom the F ront
P
an e l or by HP- ΙΒ co mm an d. Th e various sign al blocks are
also
ch eck ed for output . Th e output sig nals are appli ed to
m ultipl exer
U
70 and are se lected in
t
urn vi a its 3 address lines . The se lected
si gnal
i s th en buffered in U 71A
a nd appli ed to U 72
f
or Α -D
co nvers i on . Th e resulting data is comp ared by the mi cro processor
to
f
all within acceptable upp er and
l
o wer limits .
Fu
nctio
n
al Descri
p
tio n 7- 29