Tektronix DD 501 Instruction Manual page 19

Fig.
3-3.
Counter
Control
Timing.
U
cn
U230A
pin 2
(derived
from
START
trigger.)
U44A
pin 2
(derived
from
EVENT
trigger.)
_n_n
COUNT
BEGINS AT
99988
89
U271 pin 12
(CLOCK)
U272
pin 2
(8
BIT)
U271
pin 15
(1
BIT)
U240
pin 9
(99990 detected)
U210A
pin
2
90
U210C
pin 15
U210C
pin 9
(99999 detected)
U210B
pin 3
U230B
pin
15
(pin
14 processed
as
OUTPUT
pulse.)
U274
pin 2
U232B
pin 15
U232A
pin 2
1818-15
Theory
of
Operation—
DD
501