Tektronix 7704A User Manual

Ci r cu it Description -7704A Service
Selection
M
atrix was a dd resse d to ob tai n information in
each time-slot
.
T he
column d ata
c h
anges to enco d e t h e
a pp
lica b le rea d out d
ata
as t he
op
erating
conditions
c h ange .
F or examp le, if t he varia b le co n trol
of
t h e plug-in un
it
was
activated, R 130 wo u ld be connecte d betwee n time-slot 3
and t
h e column analog
d ata
out
p ut
line
.
T h
is enco d
es
10
units
of
column current
(see s
h
aded area in time-slot 3 of
t he waveform s h ow n i n F ig . 2-41 Β ) . Since one unit
of
row
curre n t is also enco d ed during t h is time-slot by R30, α >
sy m bol is a dd ed to t h e d is p lay . T he CRT rea d out will now
s h ow + >100 μ V . In α similar manner, t h e ot h er switch es
can c hange t he e n co d e d d ata for t h e col u m n out pu t and
t h ere by c h ange t h e reado u t d is p lay . See t he descriptions
w h ic h
follow for d eco d i n g t
h
is information .
T h e column analog d ata e n co d e db y most plug-in units
can be
modifie
d by attenuator
p
ro b es connecte d to t
h
e
in p
ut
connectors of am p lifier p lug-in units
.
Α s
p
ecial co
d
ing
ring around t he input connector of th e plug-in unitsenses
the atte n uation ratio of t h e p robe (wit h rea d o u t-co d e d
p rob es only) . T h e pro b e contains α circuit w h ic h provi d es
ad d itional column c u rrent . F or exam p le, if α 10 Χ
atten u ator pro b e is connecte d to α plug-in un it e n co d e d for
100 microvolts as s h own in F ig . 2-40, an a dd itional unit of
current is added to t h e col u m n analog d ata during time-slot
1 . Since
two
u
nits of cu rrent were encoded b y R 111 (see
F ig .
2-40), t
h
is ad d
itional current
res
u
lts in α total of th ree
units of colum n
analog
current
d
u ring
t
h
is time-slot .
R eferri n g
to t
he C h aracter Selectio n M
atrix, th ree units of
col u mn cu rrent, along with
t
h e
two units of row cu rre n t
enco d e d by
R10,
in d
icates t
h
at t
h
e prefix s h o u l d b e s h ifte d
one col u mn to t he left . Since
t
h
is
i n
str
u
ction occ u rs i n t h e
same time-slot t h at p revio u sly in d
icated t
h
at two zeros
sh ould b e added to t h e d is p lay an d
only
one instruction
can
be enco d ed du ri n g α time-slot, t h e zeros
do not
a
pp
ear
in
t h e d isplay . T h e C R T readout will now be c h a nged
to
1 mV
( r ead out program prod uced by p lug-in same as for p revious
example) .
L i k ewise, if α 100 Χ rea d o u t-co d e dp rob e is connecte d to
t h e in put of t he p lug-in unit, t
h
e col
u mn
current d
u
ring
time-slot 1 will b e increase d two units for α total of four
units of colum n cu rrent .
T
h is a d dresses an instruction in
t h e Ch aracter Selection M atrix to s h ift t he prefix an d add
one zero to t he display .
T h
e resultant C
RT rea
d o
u
t wit
h
t h e previous program is 10
m
V .
T h ree
ot
h er lines of information are co nn ected from t h e
p lug-in compartme n ts to t he Rea d out System . T he column
a n d row analog data from Ch annel 2 of α d u al-c hannel
plug-in are con necte d to t h e Rea d ou t System t hrough
termi n als Α 38 a nd Β 38 of t h e p l u g-in interface,
respectively .
F
orce rea dou t information is enco d ed on
termi
n
al
Α
35 ; t
he f u
nction of t
h
is
input
is d
escribe
d
u nder
Colum n an d Row Data Switc h es .
2- 50
F ig . 2-41 . I d ealize d c u rre n t waveforms of :
(
Α ) Row an alog d ata,
( ΒΙ Col u m n a n alog d ata .
T he preceding i n formation gave α typical exam p le
of
enco d ing d ata from an amplifier plug-in unit . Specific
enco d ing data and circuitry is s h own in t h e in d ivi d ual
plug-in unit man u als .
Colum n an d R
ow
Data
Switc h
es
Th e encodi ng d ata
from t h e plug-in u nits is connected to
t h e Column a nd
Row
Data
Switc h stages . Α col u mn-data
line and α row- d ata
line convey
a
nalog data from each of
t h e eig h t data sources (two
ch
a
n nels from each of t h e four
pl u g-in compartments) .
T h e Colu mn Data Switc h U 2030 and t h e Row Data
Switc h U 2070 receive t h e C hann el Address Co d
e from
t
he
C han nel Counter . T h is b inary code d irects t h e Column Data
Switc h an d t he Row Data Switc h as to w h ic h
c
h
annel
s hould be t he so u rce of t h e enco d i ng data . Ta b
le
2-3
gives
t
h e eig h t com b inations of t he C hannel A dd ress Co d e a nd
t
h
e resultant c
h
an
n el selecte d with each com b inatio n .
T h ese stages have n ine i npu ts an d provi de α
R \
Time-Slot -~
ι
1
ι 2 ι
3
ι 4 ι 5 ι 6 ι 7 ι 8 1 9 ι 10 i
R λ
ι
-
Ι
R-2 :
R-3 _
R-4 ~
-
R-5
R-6
R-7
R-8
R-9
R-10
( Α )
Ti m e-Slot
-0
Col .
ι
1
1 2 ι 3
ι
4
ι
5
ι 6 ι 7 ι
8
ι 9 ι 10 ι
ι ι Ι ι
"" ι
C-2
ι
ι
ι ι
C-3
ι
ι
; ι
C-4
ι Ι
C-5
ι ι
ι
ι
C-6 ι ,
C-7-
ι
C-8-
ι
ι
ι
ι
C-9
ι
ι
C-10 ~ '
( Β )
Program for 100 μ V , inve r te d , cali br
ate d ( un cali b rate d o p
eratio n
s h ow n by s haded a r ea)

Tektronix 7704A Specifications

General

Brand	Tektronix
Model	7704A
Category	Test Equipment
Language	English