Yamaha CS-80 Instruction Manual page 48

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4
44
that converts the
time
interval
between
switch contact
opening and
closing into
a
brief
output
voltage
pulse.
The
faster
a
key
is
pressed
down,
the shorter the
time
of
switch contact
action,
and
the higher the voltage
level
of the
pulse.
The
key timing
circuit
pulse
is
used
to create various
initial
touch
sensitivity (velocity
sensitive) effects,
depending on
how
the
presets, pro-
gramming, and
TOUCH
RESPONSE
sections are
set.
PITCHBEND
[12]
is
an
initial
touch
sensitivity
effect
whereby
the
timing
circuit
pulse
is
reversed
in
polarity
and
applied to the
VCO.
Thus,
the
frequency
of
the
VCO
is
initially
forced lower by the
negative
voltage pulse
from
the
Key Timer
Circuit,
and
then
comes up
to
the
note's
designated
frequency
as
the
pulse
dies out.
The INITIAL
LEVEL
lever
[43]
in
the
program-
ming
panel applies the
key timing
pulse to the
VCA,
thus
increasing the
volume
of
the note
for
the duration
of the
pulse.
The
faster
you
strike
a
key, the higher
the voltage pulse
and
the higher the
volume.
This
effect
is
programmed
into
some
of the preset patches.
Similarly, the
INITIAL
BRILLIANCE
lever
[42]
applies the
key timing
pulse to the
VCF,
thus
raising
the
cutoff
frequency
of
both
filters.
This
increases the
amount
of high frequencies
which
can
pass
through
the
VCF
by an
amount
proportional
to the voltage of
the
timing
pulse,
and
only
for the
duration
of the
pulse.
Pressure Sensitivity
A
sensor
beneath
the front of
each key
is
used
for
the
AFTER
(pressure
sensitive) effects.
The
harder
you
press
a
key
after
it
first
touches bottom,
the
higher the voltage
allowed
to
get
through
a
variable
pad
in
the
key's sensor.
Various
effects are
produced
by
the
voltage,
depending on
how
the
presets,
pro-
gramming, and
TOUCH
RESPONSE
sections are
set;
the
keyboard's
after
voltage
is
applied to the control
input
of the
appropriate voltage controlled
circuits.
Keyboard
Control
The
keyboard
control
HIGH
and
LOW
levers
affect
the
upper and lower
portions
of
the
keyboard
separately,
with
increasing effect
toward
the
ends
of
the
keyboard. Thisis
done
for
LEVEL
and
for
BRILLIANCE.
The
effect
is
actually
achieved
by
a
digital
circuit
which
interprets
the position of
each
note played
on
the
keyboard and produces
a
pro-
portional
amount
of
dc
voltage.
With
the
HIGH
levers,
the higher the note, the higher the voltage.
With
the
LOW
levers,
the
lower
the note, the higher the
voltage.
If
a
BRILLIANCE
lever
is
engaged,
the extra voltage
is
added
to the
VCF,
raising
the cutoff
point
for
a
more
brilliant
sound.
If
a
LEVEL
lever
is
engaged,
the
extra voltage
is
added
to the
VCA,
increasing
the
volume
of the note.
(BRILLANCE
and
LEVEL
are
decreased
by
reversing the polarity of the
keyboard
control
voltage.)
Portamento/Glissando
The
glissando effect
is
produced by
a
digital
circuit
which
"looks at" the
last
note played
and
at
the
note
being played. Instead
of
allowing the voltage fed
to the
VCO
to
jump
instantly to
the voltage
called for
by
the
note being played, the
glissando
circuit
gradually
moves
the voltage
from
that of the previous
note
to the
currently
played
note.
A
digital
circuit
causes the
voltage to increase or decrease
in
quantized increments
that
correspond
to
half-step
increments
(a
chromatic
scale).
The portamento
effect
is
actually
produced
by
the
same
circuit
that
produces
the
glissando,
except
that
an
additional
circuit
element
is
added.
This
element
"integrates" the steps of
voltage,
smoothing
the
transi-
tion
from one
note
to
the
next.
Thus,
the
change
is
continuous
rather
than stepped.
Ribbon
Controller
The
ribbon
controller
is
a felt
strip
beneath which
is
located
a flat resistive
pad and
a
conductive
cord.
When
you
press
down
on
the
felt,
the
cord contacts
the
pad
and
establishes
a
given
resistance.
Voltage
passes
through
the
pad and
the cord, the value varying
in
proportion
to
where
the
strip
is
pressed
down. The
actual
voltage
produced
when
the
ribbon
is
first
pressed
down
is
not important;
it
serves
only
as
a
reference
point.
The
output
from
the
ribbon
circuit
then
be-
comes
proportional
to
the difference
between
the
reference point
and any
other point
touched on
the
ribbon.
A
comparator
circuit
"looks at"
the
change
in
voltage
and produces
a
positive
dc output
when
the
second
point
touched on
the ribbon
is
to the
right
of
the reference point.
A
negative
dc output
is
produced
when
the
second
point
is
to
the
left
of
the reference
point.
The
further
away
the
second
point
from
the
reference point, the higher the voltage
output
(positive or negative).
No
voltage
output
is
produced
if
only
one
point
is
touched.
It
is
necessary to
move
a
finger
along the
ribbon,
or to
hold one
finger
in a
given
point
and
then
touch another
finger
elsewhere
on
the
ribbon
in
order
to achieve
an
effect.
The
voltage
output from
the
ribbon
controller
is
fed to the
main VCO's,
thus
changing
the pitch of
any
note
or
notes being played;
a
positive
voltage
would
raise
the
pitch,
and
a
negative voltage
would
lower
the
pitch.
Pitch
Control
&
Detune
CH
il
Control
The
pitch
control
adds
more
or
less
voltage to "bias"
the
VCO
control
inputs,
thus
raising
or
lowering the
frequency produced
when
a
given
key
is
depressed.
The
pitch control feeds
both channels an equal
amount
of voltage.
The
coarse
pitch control
merely
produces
a
greater
range
of
voltage variation
than
the
fine
pitch control.
The Detune
CH
II
control
really
does
the
same
thing
as
the
fine pitch control,
but
it
is
connected
only
to
channel
II.
Thus, only
the pitch of
channel
1
1
changes.
Ring Modulator
A
Ring
Modulator
blends
two
signals
together
in
a
special
way, "beating"
a
sub
oscillator
against
whatever
input
signal
is
fed to the
modulator
input.
The
output
does not contain
the input
signal
frequency
(or
frequencies),
but
it
does contain
what
are
known
as
sum
and
difference frequencies.
Sum
and
difference
simply
means
that the
sub
oscillator
frequency
is
added
to
the input frequency,
and
is
also
subtracted
from
the
input frequency.
(Actually, the
mathematics
that describe the
modulation
are
somewhat more
complex
because
two
times the
sub
oscillator
fre-
quency
is
subtracted
from and added
to the input,
three times the
sub
oscillator
frequency,
etc.).
The
effect
may
resemble
"ringing,"
although
the
term
"ring
modulator"
is
believed to be derived
from
the
configuration
of
the diodes
which comprise
such
modulators; they
are
wired
in a circle.
The
sub
oscillator
frequency
is
set
with the
SPEED
lever,
and
the
amount
of
sub
oscillator
voltage fed to
the
ring
modulator
is
set
with the
MODULATION
lever.
An
envelope generator
is
provided
for
the
sub
oscillator,
and
may
be used to
change
the
speed
when
a
note
is
played.
The
ATTACK
TIME
lever
and
DECAY
TIME
lever
respectively
speed
up and
slow
down
the
effect
from whatever
speed
is
set
with
the
SPEED
lever
to
some
higher
value,
and back
to the
set
speed.
The
amount
of
change
in
speed—
the
amount
of
envelope
voltage fed to the
sub
oscillator-is
set
with
the
DEPTH
lever.
Panels,
Memories
&
Preset
Patches
The
main programmable
panels provide
a
means
for
the player to adjust the
many VCO,
VCF
and
VCA
characteristics,
as
well
as
touch
response
characteristics,
that together
comprise
a
basic
"patch"
or
sound.
The
memories
are
miniaturized
versions of the
program-
ming
panels,
and
are
used
in
exactly the
same
v\/ay.
The
preset
patches
(PRESET TONES)
were
all
derived
from
actual settings of the
main programmable
panels.
Once
a
given
patch
was
derived, the resistance value or
switch
position of
each panel control
was measured.

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