Tektronix 7704A User Manual

O
utput Signal
Input
Φ = H as no effect i n t h is case .
O utput
Fig . 2-27 . Input/outpu t ta b le
for Ho r izo n tal Plug-in Selector .
Wh en
t
he H O R IZO N TA L M OD E switc h is set to Α , t h e
level at p in
4
is
L 0 . T h is level allows t he sig n al from the Α
h orizontal unit to p ass to
t h e outpu t w h ile t he signal from
t h e Β h orizontal
u nit is b loc ke d . In t h e Β p osition of t h e
H
O
R IZO N TA L M OD E switc h , t h e level at pi n 4 is HI .
Now, t
h e signal from t h e Β h orizo n tal unit is con n ecte d to
t
h e outp u t w h ile t he signal from t h e
Α
h orizontal
un it is
bloc
ke d .
F or A L T or CHO
P positions of t h e H O R
IZO N TA L
M OD E switc h , t h e
MF Ch annel Switch Signal (Display
Β )
at
p in 4 switc h es
between t h e L O an d HI levels at α
rate
d etermined by t
he H orizontal B inary stage
in t he Logic
Ci r cuit .
T h is action allows t he signals
from t h e Α h orizontal
u nit to be d isplaye d w
h
en t
he MF Chan nel Switc h Signal
(Display Β ) is L O an d t
h e signal from t h e Β h orizontal
un
it
to be d isplaye d w h
en
t h
e MF Ch annel Switch Signal
(Display
Β ) is ΗΙ .
T he V - Η ( V ertical-
H orizontal) In h i b it from t
h e Rea dout
System, applie d to pi
n 6, h as final cont r ol
over
t he
out
p
ut
signal fr om this stage .
Quiescently, t h is sig n al is
L O
to allow
t he signal from t
he selecte d h orizontal unit to p
ass to t h e
outpu t . H oweve r , w
hen t he Reado u t System is
ready to
display readout
information, t h e level at pin
6 goes ΗΙ . T h is
level b loc k s t he
sig n
al
fr om bot h h orizontal
u nits, so t h ere
is no signal out p ut from
t h is stage unde r t h is co
n
dition
.
H orizontal B
uffer
T h e out pu t
sig n al from t he H orizontal
Plug-in Selector is
connecte d to
t he H orizontal Am p lifier
circuit t h ro u g h t he
H o r izo
n
tal
Bu ffer stage . T r ansisto rs Q2331-Q2337
provi de
α low load
impedance for U 2320 as
well
as
provi d ing DC
voltage matc h ing between t
he H orizontal Interface an d
H orizontal Am p lifie
r circ u its .
V ertical Signal Amplifier
Sawtoot h Am p lifier
Gate Am p lifier
Ci
r cu it Description-7704A Service
OU T PU T SIG N A L S
T he Output Signals circuit provi des
signals to the
connectors located in
the OUTPUTS section of the rear
p anel . These output
signals are either generated within the
instrument or
are samples of signals from the associate d
plug-in u nits . In a dd itio n , t h is circuit co n tains t h e mo d
e
selection for
the Readout System . F igure 2-28 s h ows α
detaile d bloc
k d iagram of t h e Out p ut Signals circuit .
T he vertical signal selected by the
Β Trigger Selector (see
Trigger
Selector d escription for more
information) is
connecte d to
t he b ases of transistors Q3306-03308 .
T h e
amplifie d
signal is conn ecte d to b uffer
Q3312-03315
t hroug
h
an
RC networ k w h ic h p rovides t
h ermal balance fo r
t
h
e
circuit . C R 3315 and C
R
3317 p rotect
t h is stage if
h ig h -level voltages are accidentally app lie d to
t he VER T
SIG O U T conn ector . CR 3315 pr
ovides pr otection from
p
ositive voltages and CR 3317 pr
ovides p rotection from
negative
voltages .
T h e sawtoot h sig n als from t
h
e
Α
and
Β ti m e-base units
a r e conn ected to t he Sawtoot
h Am p lifier stage t h roug h
series resistors R2029 and
R2019 res p ectively
(See
Diagram
2) .
Swee p Selector switc h S3320 d
ete r min es w h et
h
er t
he
Α -sweep or t he Β -sweep sawtoot
h signal p rovi d es t h e
+SA W TOOT H O U T signal .
T h
e
unuse d sawtooth signal is
terminate d b y R 3320 to p rovide α
constant loa d to t he
signal source .
03321-Q3323-Q3330
compose an inverting fee dbac k
amplifier . Gain of t
h e stage is about two, as determine
db y
t h e ratio of
fee db ac k resistor R3328 to t
h
e
i nput resistance
(made up
of R3321 and eit
h er R2029 and R2019,
d ependi
ng on w h ic h sawtoot
h source is selecte d
)
. RC
networ
k R 3330-C3330
provides frequency- r es p
onse
sta
b ilization for t h is stage
.
CR 3326 p rovides p rotection
from h ig h -amplitu de p
osi-
tive
voltages ina d vertently
con n ected to t
h
e
outp u t
conn ector .
T h is d iode provi
d es α cu r rent p at
h to t h e
+15- V olt
s up ply th roug
h t h e collecto r - b ase j
unction of
Q3330 . Wh
en the diod
e is forward b iase d , it
clamps t h e
base of
Q3330 at +15
volts . CR 3333 pr ovi d es
protectio n
from h ig h -am p litu d
e negative voltages at t
h
e
SA W TOOT H
O U T con nector b y
clampi ng t he output if it
attem p ts to go
more negative t han a
b
o
u t -15 .6 volts .
T h e + GAT
E
O U
T signal is selecte d
from th ree inp u t
gate
signals by Gate
Selector switc h
S3340 . In t h e Α
position, t h e Α Gate
signal from t
he Α H O R IZ com p art-
2- 3 1
L O L O
Α Ho r izo n tal
HI L O Β Horizontal
(D HI
Neither Iblocked by
readout system)

Tektronix 7704A Specifications

General

Brand	Tektronix
Model	7704A
Category	Test Equipment
Language	English