7.
Tone Color Parameters
A
tone color consists of various parameters,
there-
fore, to edit a tone
color, change
the values of
those parameters.
a. Synthesizer Structure
The a
JUNO's synthesizer section
consists of
several blocks as shown in the picture.
Each
block
of the synthesizer section is
controlled by
relevant tone-color parameters.
®
DCO
Block
©
LFO
Block
HPF
Biock
VCF Block
Audio Signal
Control
Signal
®
VGA Block
Modulation Pitch
Lever
Bender
T
Keyboard
Chorus
Biock
Output
®
ENV Block
DCO (Digitally Controlled Oscillator)
DCO is the
digitally controlled
oscillator that con-
trols the pitch and generates the waveforms
that
are the sound
source of the
synthesizer.
@
HPF (High Pass Rlter)
The HPF
{High-Pass Filter) is
a
filter
that passes
high
frequency harmonics and cuts off the lower
ones.
This changes
the
waveform and controls
the
tone
color.
CD
VCF (Voltage Controlled Rlter)
Each
VCF lets lower frequency harmonics of the
input signal pass and
cuts
off the higher ones. In
other
words, it Is a usual low pass filter.
By con-
trolling the cutoff
point
and resonance, the
waveform
changes, thereby
the
tone color alters.
®
VCA
(Voltage Controlled
Amplifier)
After filtered
in the
VCF, the signal is
fed to the
VCA
where the
volume
{amplitude) of the
sound is
controlled.
(D
CHORUS
(6)
LFO
(Low
Frequency
Oscillator)
This
oscillator
generates
extremely low
frequency,
so
produces a
vibrato
or growl effect
by control-
ling the
DCO
or VCF.
(7)
ENV
(Envelope
Generator)
This
generates
the
control voitage
(Envelope)
which
controls the DCO,
VCF and VCA,
therefore,
alters
the pitch,
tone color and
volume in
each
note.
18
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