Tektronix 2235 User Manual

T heory of O p e r ation-2235
Service
3- 6
FR O M C HA
NNEL
1
ATT
ENU ATO R
C HA NNEL 1
A MPL /S W Ι TC H
U 13 θ
D I OD E
S W I TC H I NG
C R2
0
0 ,
C R 20 1 ,
CR2θ2, CR 2θ3
L OGIC
S55 θ , U54 ΘΑ
U5408,
U537A
U537C, U537D
FRO M C HA
NNEL 2

C H ANN EL 2
ATT
ENU ATO R

Ah P U SWITC H
U 180
Fig
u re 3-2 . B loc k d iag r a m
of t he C hann el Switc h i ng
ci r c u itry .
α 206-12
Co u p ling
capacito r C547 a n
d
r
esistors R 547 an d R 548

Delay L i ne Drive
r
form α d iffe r
entiati n g ci r cuit t h at p
ro duces p ositive- and n
eg-
ative-goi ng sh
ort- d uration pulses . T h
ese pulses are inverted

The Delay
L ine Driver converts t h
e sig n al current from
U537 B to
ge
n
erate t he C h op B lan k
sig n al utilized b y t h
e

the V ertical
Pream p lifiers or t h e Trigger V
iew circuitry into b y

α
b y Axis Am p lifier .

signal voltage
for i npu t to t h e Delay
L ine . Transisto r s 0202,
0203,
Q206, and Q207 form α
differential s hu
nt-feedbac k
am p lifier wit h
t
h
e gai n controlled b y R
216and R 217 . Ampli
T h
e
Alt
Sync signal ap plie d
to one in p ut of U 537A
is HI

fier com p
ensation is p rovide d by C210
and R 210 and out
pu t
except during H
oldoff . T h is allows t h
e out pu t of U 537C
to

common-mode
d o sta b ilization b y
U 225 . S h ould t he voltage
be inverted
by U537A w h ic h drives
t h e cloc k input
of

at t he j un ctio n
of R 222 and R 223 deviate
from zero, U225
U540A . Si n ce t h
e Q outpu t of U540A
is con necte d bac k
to

will sin k or
source b ase current to
Q202 and Q203 t hr oug h
t he D i npu t
a
n
d both t he S and R in p uts
are ΗΙ , t he o u t p uts

R202 and R
203 . T h is will retur n t h
e outpu ts of t he
Delay
of U540A will
toggle wit h eac h
cloc
k
input . T he Delay L i ne

L ine Driver to
an average do value of
zero volts . Delay L i n
e
Driver will t h
e
n
be driven alter n ately
by t he C h annel 1
and

D
L 210 p rovides
α vertical signal delay
of about 90 n s
so
C ha n nel

2

Pream p lifiers

at

α

rate

determined

by

that t h e Swee p
Generator has sufficie n
t time to produce
α
multivibrator
U 537D .

sweep before
t h e vertical signal t h at triggered
t he swee p
reac hes t h
e crt deflectio n plates . T h
is permits viewi ng t he
lea d ing e d
ge of t h e internal signal
t
h
at originate d t he trigger
A L T ERN
AT E DIS PL AY . In t h
e A L T p ositio n , t h
e C h o p

p
ulse .
Enable line is h el d HI and m u ltivi
b rator U 537D
is disable d .
T h eo u t p
ut of U 537C will b e L
O and t h e C h o p B la nk sig
n al

Vertical O u
t pu t Am p lifier
from U537 B
will also be L O . In p
ut sig n als to U537A
will b e
t h e L O from
U537C and t he Alt
Sy
n
c signal from t h
e Holdoff

T h e V ertical
Outp u t Amplifier p r ovi d
es final am p lificatio n
circuitry in t h
e
Α
Sweep Gene r ator . T
he o u t p ut of
U537A

of t he in p ut
signals for a pp lication
to t he vertical d eflectio n
will t hen be t h
e inverted Alt Sync
sig n al w h ic h
cloc
k
s

p lates of the
crt . Sig n als from t he
Delay L ine are ap plie d to
α
U540A . Th
is causes t h e out pu ts of
U 540A to toggle at t h
e

differential amplifier
com p osed of Q230
and Q231 wit h
low-
end of each
swee p so t h at t he C h
annel 1 and C h annel 2

and h ig h -fre q uency
com p ensation p rovide
d by t h eR C net-
P reamplifier sig n
als will alternately
drive t he Delay L
ine

wor k s connecte d
betwee n t he emitters . Th
ermal com pensa-
Driver .

tion is p rovided
by R T236, a nd overall gain
is set b y R 233 .

Tektronix 2235 Specifications

General

Brand	Tektronix
Model	2235
Category	Test Equipment
Language	English