Tektronix 7704A User Manual

Circ u it Description -7704A Service
V ertical B uffer
V-H INHIBIT
2-30
SIG N
A
L FR
O
M `
Α '
H O R IZO NTAL UN
IT
SIG NA L
FR
O M W
H OR IZO N
TAL
U
NIT
MF
CH A NN EL
S W ITC
H SIG NAL
(DIS PL AY Β )
Φ = H as no effect in t h is case
ΑυχΥ Axis or
V e ι t Trace Sep aratio n
F ig . 2-25 . Input/outpu t ta b le for V ertical T r ace Se p a r atio n stage .
Th e ou t p uts of t h e V ertical
Plug-In
Selector an d V ertical
Trace Separation stages are connecte d to t he emitters
of
Q2241-Q2242 . T h is tra n sistor p air is connected in
t
h e
common-base configuration to p rovi d e
a low-impedance
loa d to t he previous stages . Centering a d ju stment R 2222
sets t h e quiescent level
on
t h e base of Q2242
to ad j
ust
t
h e
trace p osition w h en no in p uts are app lie d
to
t h is circuit
.
Gain ad j ustment R 2247 sets t h e collector degeneration of
Q2241-Q2242 to a d j ust t h e stage gain . Q2255-Q2263 are
connecte d in t he commo n -collector configuration (emitter
follower) to provid e α low-impedance reverse termi nation
for t
h
e delay line .
F ig . 2-26 . H orizontal I n terface ci r c u it d etaile d bloc k d iagra m .
H O R IZO N TA L IN T ERF AC E
T h
e
H
orizontal
I n terface circuit determines w h
et
h er
t
h e
sig n
al
from
t
h e out p ut of t he Α h orizontal or Β h orizontal
p lug-in
unit provi d es t he h orizontal d eflection signal . T h is
circuit also acce
p
ts as in p ut
from t he R
ea
dou t System to
block t he h orizontal signal w
h ile rea d out information is
d is p laye d on t h e C
R T . F igure 2-26 s h ows α d etailed b loc k
d iagram of t he
H
orizontal
Interface circuit .
H orizontal
Plug-In Selector
T he H orizontal
Plug-in Selector determines w h ic h input
sig n al provides t
h
e
h orizontal d eflection signal to t h e
H orizontal Am p lifier as
controlle d by t he MF ( M ain F rame)
C h annel Switc h Signal
(Display Β
)
from t h e L ogic Circuit .
R esistors
R
2301-
R
2302
an d R 2303- R 2304 establis h t h e
input resistance of t
h is stage and p rovide α load for t he Α
and Β h orizontal u n its . R
esistors R 2317- R2319 and
R 2327- R2329 establis
h t h e operatin g levels for t h is stage .
R 2311- R 2313-
R
2315-
R
T2315 an d
R 2321- R 2323- R 2325-
R T2325 establis h t
h
e current gain
for each channel .
R 2313 and
R
2323 are ad j
usta b le to matc h t h e curren t
gain of t he two
c
hannels .
T hermistors R
T2315
an
d
R T2325 provi d e tem p erature compensation to sta b ilize
t h e current gain for eac h c
h
annel
.
T h is stage is ma d
e
up
primarily of
U 2320, t
he same
type
of IC as used
i n t he Trigger Selector and V ertical Interface
circuits . An
in p ut/out p ut table for U 2320 is s h own in F ig .
2-27 . U 2320
provi d es α h ig h-im ped ance differential input
for
t
h e signal from t h e Α h orizontal unit at pi n s 2 an d 15
an
d t he signal from t h e Β horizon tal un it at pins 7 and 10 .
T
h
e output signal at p ins 12 an d 13 is α d iffere n tial sig n al
to
d rive t he H orizontal Amplifier circuit . T he sum of t h e
DC current at p ins 12 and 13 is always e q ual to t
h
e sum of
t he DC cu rrents at pins 1, 8, 9, and 16 .
T h
is provi d es α
constant DC out put current level to t h e following stage as
t he H O R IZO N TA L MOD E switch is ch ange d .
H O R IZO N TA L SIG N A LTO
H OR IZO N
TAL A MPL I F IE R
L O L O L O
Αυχ Υ Axis
HI
L
O
L O B ot h
Φ HI L O
Αυχ Υ Axis
Φ Φ ΗΙ
N
eit he r ( B loc k e d By
R ea do u t System)

Tektronix 7704A Specifications

General

Brand	Tektronix
Model	7704A
Category	Test Equipment
Language	English