<s>
GI	O
SP0256	O
refers	O
to	O
a	O
family	O
of	O
closely	O
related	O
NMOS	B-Algorithm
LSI	O
chips	O
manufactured	O
by	O
General	O
Instrument	O
in	O
the	O
early	O
1980s	O
,	O
able	O
to	O
model	O
the	O
human	O
vocal	O
tract	O
by	O
a	O
software	O
programmable	O
digital	O
filter	O
,	O
creating	O
a	O
digital	O
output	O
converted	O
into	O
an	O
analog	O
signal	O
through	O
an	O
external	O
low-pass	B-Algorithm
filter	I-Algorithm
.	O
</s>
<s>
The	O
SP0256	O
includes	O
2	O
KB	O
of	O
mask	B-Device
ROM	I-Device
.	O
</s>
<s>
The	O
SP0256	O
(	O
and	O
its	O
predecessor	O
,	O
the	O
SP0250	O
)	O
implement	O
a	O
12-pole	O
,	O
Linear	B-Algorithm
Predictive	I-Algorithm
Coding	I-Algorithm
(	O
aka	O
LPC-12	O
)	O
all-pole	O
Vocal	O
Tract	O
Model	O
(	O
VTM	O
)	O
.	O
</s>
<s>
This	O
is	O
in	O
contrast	O
to	O
its	O
contemporaries	O
,	O
such	O
as	O
Texas	B-Application
Instruments	I-Application
LPC	I-Application
Speech	I-Application
Chips	I-Application
,	O
which	O
used	O
an	O
8kHz	O
sample	O
rate	O
with	O
a	O
10-pole	O
model	O
,	O
and	O
realized	O
their	O
VTM	O
with	O
a	O
lattice	O
filter	O
.	O
</s>
<s>
The	O
SP0256	O
combines	O
the	O
VTM	O
with	O
a	O
simple	O
controller	O
that	O
loads	O
compressed	O
coefficient	O
data	O
into	O
the	O
VTM	O
,	O
either	O
from	O
the	O
on-chip	O
ROM	B-Device
,	O
external	O
speech	O
ROMs	O
such	O
as	O
the	O
SPR-128	O
,	O
or	O
in	O
the	O
case	O
of	O
the	O
Intellivoice	O
,	O
an	O
SPB640	O
speech	O
data	O
FIFO	B-Operating_System
.	O
</s>
<s>
These	O
variants	O
differed	O
primarily	O
in	O
their	O
mask	B-Device
ROM	I-Device
content	O
.	O
</s>
<s>
It	O
contains	O
59	O
allophones	O
primarily	O
intended	O
for	O
use	O
with	O
English	O
language	O
phrases	O
and	O
five	O
pauses	O
in	O
its	O
internal	O
16Kb	O
(	O
2KB	O
)	O
ROM	B-Device
.	O
</s>
<s>
The	O
SP0256-AL2	O
needs	O
the	O
control	O
of	O
an	O
external	O
microprocessor	B-Architecture
to	O
concatenate	O
allophones	O
into	O
words	O
.	O
</s>
<s>
The	O
SP0256-AL2	O
was	O
available	O
in	O
home	O
brew	O
kits	O
for	O
speech	B-Application
synthesis	I-Application
published	O
in	O
specialized	O
magazines	O
for	O
microcomputers	B-Architecture
such	O
as	O
the	O
VIC-20	B-Device
,	O
and	O
Atari	B-Device
8-bit	I-Device
family	I-Device
.	O
</s>
<s>
Other	O
companies	O
produced	O
add-ons	O
for	O
various	O
8-bit	O
microcomputers	B-Architecture
,	O
like	O
Currah	B-Application
MicroSpeech	O
and	O
the	O
Tandy	O
Speech/Sound	O
Program	O
Pak	O
for	O
the	O
TRS-80	B-Device
.	O
</s>
<s>
Mattel	O
's	O
Intellivoice	O
attachment	O
for	O
its	O
Intellivision	B-Operating_System
video	O
game	O
system	O
uses	O
the	O
SP0256-012	O
.	O
</s>
<s>
This	O
variant	O
contains	O
only	O
Mattel-specific	O
game	O
phrases	O
,	O
including	O
the	O
energetic	O
phrase	O
"	O
Mattel	B-Operating_System
Electronics	I-Operating_System
Presents	O
,	O
"	O
phrases	O
for	O
digits	O
,	O
and	O
a	O
couple	O
additional	O
game	O
phrases	O
.	O
</s>
<s>
The	O
part	O
set	O
also	O
contained	O
the	O
SPR016-117	O
,	O
an	O
external	O
serial	O
speech	O
ROM	B-Device
.	O
</s>
<s>
The	O
Magnavox	B-Application
Odyssey²	I-Application
's	O
The	O
voice	O
attachment	O
uses	O
the	O
SP0256-019	O
.	O
</s>
<s>
This	O
variant	O
included	O
the	O
same	O
allophones	O
as	O
the	O
SP0256-AL2	O
(	O
but	O
an	O
external	O
ROM	B-Device
IC	O
is	O
required	O
for	O
the	O
allophones	O
)	O
,	O
along	O
with	O
some	O
Odyssey²-specific	O
game	O
phrases	O
.	O
</s>
<s>
Used	O
in	O
a	O
prototype	O
Fuzzbuster	B-Application
radar	B-Application
detector	I-Application
,	O
the	O
SP0264-021	O
has	O
relevant	O
phrases	O
and	O
is	O
pin	O
compatible	O
to	O
the	O
SP0256	O
series	O
.	O
</s>
<s>
An	O
FPGA	O
implementation	O
of	O
a	O
classic	O
eighties	O
speech	B-Application
synthesizer	I-Application
SPO256	O
,	O
done	O
for	O
the	O
Retro	O
Challenge	O
October	O
2017	O
by	O
Niels	O
Moseley	O
,	O
is	O
available	O
on	O
his	O
GitHub	B-Application
account	O
.	O
</s>
