User Manual
United
States
Patent
Justice
[111
3,902,007
[451
Aug.
26,
1975
i541
AUDIO
AND
VIDEO
PLURAL
SOURCE
TIME
DIVISION
MULTIPLEX
FOR
AN
EDUCATIONAL
TV
SYSTEM
[75]
Inventor:
James
W.
H.
Justice,
Murrysville,
Pa.
[73]
Assignee:
Westinghouse
Electric
Corporation,
Pittsburgh,
Pa.
[22]
Filed:
June
26,
I973
[2!]
Appl.
No.:
373,727
[52]
US.
Cl.
.....................
..
178/5.8
R;
l78/DIG.
23
[5
1]
Int.
Cl.2
..........................................
..
H04N
7/08
[58]
Field
of
Search
..........
..
178/56,
5.8
R,
DIG. 23
[56]
References
Cited
UNITED
STATES
PATENTS
2,089,639
8/1937
Bcdford
.............................
..
178/51)
3,740,463
6/1973
Youngstrom
et
al.
.............
..
17875.6
FOREIGN
PATENTS
OR
APPLICATIONS
531,159
12/1940
Unitcd
Kingdom
........
..
l78/DIG.
23
Primary
Examiner—Howard
W.
Britton
Assistant
Examiner—George
G.
Stellar
Attorney,
Agent,
or
Firm—‘M.
P.
Lynch
[57]
ABSTRACT
One
or
more
audio
signals
are
transmitted
and
re—
ceived
on
conventional
video
subcarriers
during
blanked
guard-band
intervals
in
the
horizontal
scan
lines
forming
one, or
less
than
all,
of
a
plurality
of
branched
video
pictures.
In
the
branching
system,
a
single
TV.
channel
is
used
to
transmit
and
receive
two
or
more
separate
video
pictures
by
selecting
a
hori'
zontal
scan
line
from
one
picture,
disregarding
succes
sive
scan
lines
thereof
until
one
successively
occurring
scan
line
from
all
of
the
pictures
to
be
transmitted
has
been
selected
and
then
selecting
the
next
available
scan
line
of
the
first
picture.
This
processing
is
then
repeated
continuously
for
all
the
scan
lines
making
up
the'frame
of
the
pictures.
In
the
preferred
form,
the
blanked
guard-band
interval
occurs
only
during
hori—
zontal
scan
lines
for
one
of
two
pictures
transmitted.
Audio
signals
are
sampled
at
the
standard
video
scan
rate
to
form
audio
bursts,
two
of
which
are
inserted
into
only
those
horizontal
scan
lines
having
a
blanked
interval.
When
one
audio
signal
is
transmitted,
it
is
branched
into
two
lines,
one
including
a
time
delay
medium.
In
the
receiver,
the
previously
undelayed
audio
bursts
are
time
delayed
and
recombined
with
the
transmitter
delayed
audio
bursts
to
provide
a
wide
bandwidth
audio
signal.
When
bursts
of
two
or
more
audio
signals
are
received,
gating
is
used
to
recover
the
separate
audio
signals.
23
Claims,
6
Drawing
Figures
AUDIO
AUDIO
,
COLOR
A:
‘*2
Al
A2-
Al
2
r
-
REF
1
BURST
*2
#2
g
#|
VIDEO
VIDEO
#I
vmeo
VIDEO
“1
HORZ
.
HORZ
'
SYNC
I.
615/18
_|__|
|__GUARD
SYNC
PULSE
BAND
PULSE