Circuit Analysis Of R Eadout System - Tektronix 5440 Instruction Manual

Circuit Analysis of
R
eadout System
Th e following analysis of the
R
ea dout System dis-
cusses th e operation of eac h stage in
d
etail . Α com
p
lete
sc hematic of th e
R
ea
d
out System is s hown on the diagram
at the rear of t h is manual .
T
h
e defi
n
itions of several terms use
d
in t
h
is description
of th e
R
ea
d
out System follow :
C haracter- Α ch aracter is α single number, letter, or
symbol t h at is dis
p
layed on the crt, either alone or i n
combination with ot h er c h aracters .
W
or d -Α word is ma
d
e up of α related grou p
of c h aracters .
In the readout system, α wor
d
can consist of up to ten
characters .
F rame-Α frame is α dis play of all words for α given
o perating mode an
d p
lug-in combination .
U
p
to
eig ht wor
d
s can be displaye
d
in o n e frame .
Colum n -One of the vertical groups in t h e character
selectio n matrix (see Fig . 3-6) . Columns C- Ο
(Column zero) to C-10 (column 10) can be a
d
-
d
ressed in th e system .
R
ow-One of the horizontal groups in th e character
selection matrix (Fig . 3-6) .
R
ow R
-1 (row 1) to
R
-10
(row 10) can be a
dd
ressed in th e system .
Time Slot- Α locatio n in α pulse train. In the
R
ea
d
out
System, th e pulse train consists of 10 negative-goi n g
pulses . Eac h of these time-slots is assigne
d
α
number between one and te n . For example, th e first
time-slot is TS-1 .
Timer. Timer U 1000 establis hes the timing sequence
for all circuits wit hin t h e
R
eadout System . Th is stage
p roduces seven time-relate
d
output waveforms (see F ig .
3-2) . T he tria ngle waveform produced at pin 6 forms the
basis for the remaining signals. The basic perio
d
of th is
triangle waveform is about 250 microsecon
d
s, as con-
trolle
d
by R C networ k C1021- R1021 . T h e triangle
waveform is clippe
d
an d amplified by U1000 to form the
tra
p
ezoi dal output signal at p i n 10 . The am plitude of th is
output sig nal is exactly 15 volts as
d
etermine
d
by U 1000
(exact amplitude necessary to accurately enco
d
e
d
ata in
plug-in units ; see E nco
d
ing the Data) . T he trigger output
at pin 5 provides the switc h ing signal for the time-slot
counter an d readout intensity control 01018.
ι :
ιι
ι
luffl W AM,
ι
iw
Will
WAVATRIF
P
in 10
Trigger
Pin
5
C
haracter
Scan
P
in 16
Ζ- Αχίs
L
ogic
Bla nk
Pin 14
Channel
Switch
O
FF
Comman
d
P
in 13
Circuit Descri
p
tio
n
-5440
En
91/ ι
f
11
r
1111
ΙιΙ1ΙΙrail ΙΜ/115 Ι ; Ι' 1 Ι
ιι
Ετ:ιπΜτΕΜ r Ι Ι Ι Ι Ι . s Ι Ι .
1/Ιι/ill
ι
MEMO
ι
MOMMEMEMEM
ιιιι1ιιιΙιιιιιιιιιιιιιι
11101010111111010111111,
MMMMMMMMMMI
MENNEN
ιι
ωΕιιιΜΜΕιιιω
ιιιιιιιιιιιΙ1 ' ι ιιιι _ιιιιιι ι
Μ=~1
RiIMMONA
MMMMMMMMMM
200mV 200μS
R
eadout
t+6 V
Inten sity
P
in 12
-1
ffil-F
NOTE : Test oscilloscope exte rn ally trigger ed from channel
add ress 4 .
F
ig . 3-2 . Output wavefo rms of time r stage.
3-7