Casio CZ-1 Operation Manual page 22

As shown
in
Fig.
2,
the
phase
angle read
is
distorted
rather
than
linear,
and
the output cosine
wave
takes
on what
is
close
to
a
saw-tooth
pattern.
What
would happen
now
if
we
further
increase the
phase
angle read speed from through
tt
and
decrease
it
from
X
through 2x7
(Fig. 3)
(Fig. 4)
Fig.
3
shows
that
the output cosine
wave
is
almost a
perfect saw-tooth
pattern.
The
revolutionary
PD
sound
source
system
thus
makes
it
possible
to
output
waveforms
that
differ
from cosine
waves
by simply
distorting the
cosine
(or
sine)
wave
read from
ROM.
Figs.
1
through
3
illustrate
the patterns produced by
increasing the
phase
angle read speed from
through
X
while decreasing
the
speed
from
x
through
2x.
This
is
the pattern effected
when
the
SAW-TOOTH
wave-
form
is
selected
in
the
DCO
parameter.
Read
phase
angles are
also distorted
in
accordance
with the selection
of
the other
DCO
parameter
WAVE
FORMS,
thus
making
a
variety of
waveform
outputs
possible.
The
magnitude
of
the read
phase
angle
distortion cor-
responds
to
the
momentary
value
(change over
time)
of the
DCW
envelope.
When
the
DCW
envelope
is
set
as
shown
in Fig. 4,
an
undistorted
cosine
wave
is
out-
put
at point
@
,
distortion
reaches
its
peak
at
point
©
,
and a
saw-tooth
pattern
as
shown
in
Fig.
3
is
output.
Distortion
is
reduced
(modulation
becomes
shallower)
at point
Cb)
,
and
a
pattern that
is
somewhere between
a cosine wave
and a
saw-tooth
wave
as
illustrated
in
Fig.
2
is
output.
rw33 ©
•A
^
DCW
envelope
AA
/
l\
^
\
t
Key
ON Key
OFF
When
WAVE FORM
is
set
to
saw-tooth.
®
AA
^^^^^U^^^^
®
^mm
1)
The
pattern
of
the read
phase
angle
distortion
corresponds
to
the
WAVE FORM
setting of
the
DCO
parameter.
2)
The magnitude
of
the read output
phase
an-
gle distortion
(modulation depth) corresponds
to
the
momentary
value
of
the
DCW
envelope.
-21-