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Claims  |
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What is claimed is:
1. An electronic musical instrument, comprising:
envelope extraction means for extracting an envelope signal from an input
waveform signal;
musical tone generation means including means for generating a musical tone
signal, and preset envelope generation
musical tone generation means including means for generating a musical tone
signal, and preset envelope generation means for generating a preset
envelope signal to impart an envelope characteristic to the generated
musical tone signal;
envelope control means for (a) imparting, between a generation start timing
and a sustain state start timing of the musical tone signal, a constant
value to the musical tone signal to which the preset envelope signal has
been imparted and (b) imparting, from said sustain start timing of the
musical tone signal, the envelope signal extracted by said envelope
extraction means to the musical tone signal to which the preset envelope
signal has been imparted;
wherein said envelope extraction means includes:
(a) peak value detection means for sequentially detecting peak values for a
digital waveform signal obtained by digitizing said input waveform signal
after the sustain start timing of the musical tone signal;
(b) average value calculation means for calculating average values of a
present peak value detected by said peak value detection means and at
least one previous peak value; and
(c) envelope signal calculating means for calculating ratios as said
extracted envelope signal by dividing the average values successively
output from said average value calculation means by the average value at
the sustain start timing, and said constant value which is imparted to the
musical tone signal between the generation start timing and the sustain
start timing being equal to the ratio at the sustain start timing.
2. An electronic musical instrument, comprising:
envelope extraction means for extracting an envelope signal from an input
waveform signal;
musical tone generation means including means for generating a musical tone
signal, and preset envelope generation means for generating a preset
envelope signal to impart an envelope characteristic to the generated
musical tone signal;
envelope control means for (a) imparting, between a generation start timing
and a sustain state start timing of the musical tone signal, constant
value to the musical tone signal to which the preset envelope signal has
been imparted and (b) imparting, from said sustain start timing of the
musical tone signal, the envelope signal extracted by said envelope
extraction means to the musical tone signal to which the preset envelope
signal has been imparted;
wherein said envelope extraction means includes:
(a) peak value detection means for sequentially detecting peak values of a
digital waveform signal obtained by digitizing said input waveform signal
after the sustain start timing of the musical tone signal; and
(b) envelope signal calculating means for calculating ratios as said
extracted envelope signal by dividing the peak values successively output
from said peak value detection means by the peak value at the sustain
start timing, and said constant value which is imparted to the musical
tone signal between the generation start timing and a sustain start timing
being equal to the ratio at the sustain start timing.
3. An electronic musical instrument, comprising:
envelope extraction means for extracting an envelope signal from an input
waveform signal;
musical tone generation means for generating a musical tone signal;
preselected envelope signal generation means for generating a preselected
envelope signal;
selecting means for enabling a performer to select a mixing ratio of
envelope signals;
mixing means coupled to said envelope extraction means and to said
preselected envelope signal generation means for mixing the envelope
signal representing an envelope of said input waveform signal and the
preselected envelope signal generated from said preselected envelope
signal generation means at a desired mixing ratio selected by said
selecting means; and
envelope control means for imparting a mixed envelope signal obtained from
said mixing means to the musical tone signal generated from said musical
tone generation means;
wherein said envelope extraction means includes;
(a) maximum peak value detection means for detecting a maximum peak value
of a digital waveform signal at its start timing, said digital waveform
signal being obtained by digitizing the input waveform signal;
(b) peak value detection means for sequentially detecting peak values of
the digital waveform signal after its start timing;
(c) envelope signal calculating means including means for calculating an
average value of a present peak value detected sequentially by said peak
value detection means and at least one previous peak value, means for
sequentially calculating a ratio of the average value to the maximum peak
value detected by said maximum peak value detection means, and means for
sequentially outputting the calculated ratio as the extracted envelope
signal.
4. The electronic musical instrument according to claim 3, wherein said
mixing means includes:
first multiplying means for multiplying the envelope signal extracted by
said envelope extraction means with a preselected first factor;
second multiplying means for multiplying the envelope signal generated by
said envelope signal generator means with a preselected second factor; and
adding means for adding outputs from said first and second multiplying
means to generate said mixed envelope signal; and wherein
said envelope control means includes multiplying means for multiplying the
musical tone signal generated from said musical tone generation means with
said mixed envelope signal.
5. An electronic stringed instrument in which a string vibration is
detected, a pitch is extracted from the detected string vibration and a
musical tone having a corresponding tone pitch is generated, comprising:
envelope extraction means for extracting an envelope signal from an input
waveform signal representing the string vibration;
musical tone generation means including means for generating a musical tone
signal, a pitch of the musical tone signal being determined by a pitch
extracted from said input waveform signal, and preset envelope generation
means for generating a preset envelope signal to impart an envelope
characteristic to the generated musical tone signal;
envelope control means for (a) imparting, between a generation start timing
and a sustain state start timing of the musical tone signal, a constant
value to the musical tone signal to which the preset envelope signal has
been imparted and (b) imparting, from said sustain start timing of the
musical tone signal, the envelope signal extracted by said envelope
extraction means to the musical tone signal to which the preset envelope
signal has been imparted;
wherein said envelope extraction means includes:
(a) peak value detection means for sequentially detecting peak values of a
digital waveform signal obtained by digitizing said input waveform signal
after the sustain start timing of the musical tone signal; and
(b) average value calculation means for calculating an average value of a
present peak value detected by said peak value detection means and at
least one previous peak value; and
(c) envelope signal calculating means for calculating ratios as said
extracted envelope signal by dividing the average values successively
output from said average value calculation means by the average value at
the sustain start timing, and said constant value which is imparted to the
musical tone signal between the generation start timing and the sustain
start timing being equal to the ratio at the sustain start timing.
6. An electronic stringed instrument in which a string vibration is
detected, a pitch is extracted from the detected string vibration and a
musical tone having a corresponding tone pitch is generated, comprising:
envelope extraction means for extracting an envelope signal from an input
waveform signal representing the string vibration;
musical tone generation means including means for generating a musical tone
signal, a pitch of the musical tone signal being determined by the pitch
extracted from said input waveform signal, and preset envelope generation
means for generating a preset envelope signal to impart an envelope
characteristic to the generated musical tone signal;
envelope control means for (a) imparting, between a generation start timing
and a sustain state start timing of the musical tone signal, a constant
value to the musical tone signal to which the preset envelope signal has
been imparted and (b) imparting, from said sustain start timing of the
musical tone signal, the envelope signal extracted by said envelope
extraction means to the musical tone signal to which the preset envelope
signal has been imparted;
wherein said envelope extraction means includes:
(a) peak value detection means for sequentially detecting peak values of a
digital waveform signal obtained by digitizing said input waveform signal
after the sustain start timing of the musical tone signal; and
(b) envelope signal calculating means for calculating ratios as said
extracted envelope signal by dividing the peak values successively output
from said peak value detection means by the peak value at the sustain
start timing, and said constant value which is imparted to the musical
tone signal between the generation start timing and a sustain start timing
being equal to the ratio at the sustain start timing.
7. An electronic stringed instrument in which a string vibration is
detected, a pitch is extracted from the detected string vibration and a
musical tone having a corresponding tone pitch is generated, comprising:
envelope extraction means for extracting an envelope signal from an
inputwaveform signal representing the string vibration;
musical tone generation means for generating a musical tone signal whose
pitch is determined by the extracted pitch from said input waveform
signal;
preselected envelope signal generation means for generating a preselected
envelope signal;
selecting means for enabling a performer to select a mixing ratio of
envelope signals;
mixing means coupled to said envelope extraction means and to said
preselected envelope signal generation means for mixing the envelope
signal representing the envelope of said input waveform signal and the
preselected envelope signal generated from said preselected envelope
signal generation means at a desired mixing ratio selected by said
selecting means; and
envelope control means for imparting a mixed envelope signal obtained by
said mixing means to the musical tone signal generated from said musical
tone generation means;
wherein said envelope extraction means includes:
(a) maximum peak value detection means for detecting a maximum peak value
of a digital waveform signal at its start timing, said digital waveform
signal being obtained by digitizing the input waveform signal;
(b) peak value detection means for sequentially detecting peak values of
the digital waveform signal after its start timing;
(c) envelope signal calculating means including means for calculating an
average value of a present peak value detected sequentially by said peak
value detection means and at least one previous peak value, means for
sequentially calculating a ratio of the average value to the maximum peak
value detected by said maximum peak value detection means, and means for
sequentially outputting the calculated ratio as the extracted envelope
signal.
8. The electronic musical instrument according to claim 7, wherein said
mixing means includes:
first multiplying means for multiplying the envelope signal extracted by
said envelope extraction means with a preselected first factor;
second multiplying means for multiplying the envelope signal generated by
said envelope signal generator means with a preselected second factor; and
adding means for adding outputs from said first and second multiplying
means to generate said mixed envelope signal; and wherein
said envelope control means includes multiplying means for multiplying the
musical tone signal generated from said musical tone generation means with
said mixed envelope signal. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to electronic musical instruments of a
synthesizer type such as an electronic guitar, other electronic stringed
instruments and the like, and more particularly to a technique for an
electronic musical instrument for controlling an envelope of a musical
tone to be generated.
2. Description of the Related Art
Recently, electronic musical instruments have been developed wherein a
vibration of a plucked string is detected as an electric waveform signal,
and a musical tone generating circuit comprising digital circuits and/or
analog circuits is controlled in accordance with the detected waveform
signal, and thereby a musical tone is synthesized and is acoustically
generated.
In the other case, the above waveform signal can be electrically detected
from a human voice or an acoustic signal generated by playing an acoustic
instrument. There are following articles disclosing such a technique:
(a) U.S. Pat. No. 4,117,757 (issued on Oct. 3, 1978), inventor: Akamatu.
This patent discloses an electronic circuit for forming a waveform signal
in which "1" and "0" sequentially inverted at positive and negative peak
points of an input waveform signal. This waveform signal is converted to a
rectangular wave signal, and its frequency corresponds to a pitch of the
input waveform signal.
(b) U.S. Pat. No. 4,606,255 (issued on Aug. 19, 1986), inventor: Hayashi et
al.
This patent discloses a guitar synthesizer. A pitch is extracted for each
string to obtain a corresponding voltage signal, and a musical tone signal
is generated by voltage control.
(c) U.S. Pat. No. 4,644,748 (issued on Jan. 6, 1987), inventor: Takashima
et al.
This patent discloses a technique for converting an acoustic signal input
through a microphone into a digital signal, and extracting a pitch by
digital processing.
(d) U.S. Pat. No. 4,688,464 (issued on Aug. 25, 1987), inventor: Gibson et
al.
This patent discloses a technique for extracting a pitch in accordance with
time intervals crossing three threshold levels, i.e., high, middle, and
low threshold levels of an input waveform signal.
(e) Japanese Patent Publication No. 57-37074 (published on Aug. 7, 1982),
applicant: Roland Kabushiki Kaisha.
(f) Japanese Patent Publication No. 57-58672 (published on Dec. 10, 1982),
applicant: Roland Kabushiki Kaisha.
The contents of these two patents correspond to the above-mentioned patent
(a), U.S. Pat. No. 4,117,757, and disclose techniques for generating a
rectangular wave having a frequency corresponding to a pitch of an input
waveform signal.
(g) Japanese Patent Disclosure (Kokai) No. 55-55398 (disclosed on Apr. 23,
1980), applicant: Toshiba Corp.
This patent application discloses a technique for generating a rectangular
wave having a frequency corresponding to a pitch of an input waveform
signal as in the patent (a), U.S. Pat. No. 4,117,757.
(h) Japanese Patent Disclosure (Kokai) No. 55-87196 (disclosed on Jul. 1,
1980), applicant: Nippon Gakki Seizo Kabushiki Kaisha.
This prior-art invention discloses a technique for generating a fundamental
wave pulse having a period corresponding to a pitch in accordance with a
output from a pickup of a guitar, counting the pulse by an interval
counter to obtain period data, and converting the period data into digital
frequency data.
(i) Japanese Patent Disclosure (Kokai) No. 55-159495 (disclosed on Dec. 11,
1980), applicant: Nippon Gakki Seizo Kabushiki Kaisha.
This prior-art invention discloses a technique wherein when an extracted
pitch is not varied, a musical tone is started to generate. When two
adjacent periods substantially coincide with each other, a coincidence
signal is output, and start of tone generation is instructed in accordance
with the coincidence signal.
(j) Japanese Utility Model Disclosure (Kokai) No. 55-152597 (disclosed on
Nov. 4, 1980), applicant: Nippon Gakki Seizo Kabushiki Kaisha.
This prior-art device discloses a technique wherein a vibration of a string
is extracted by an optical pickup, and the vibration of the string is
excited by a pickup signal to obtain a vibration sustain effect.
(k) Japanese Utility Model Disclosure (Kokai) No. 55-162132 (disclosed on
Nov. 20, 1980), applicant: Keio Gikken Kougyo Kabushiki Kaisha.
This prior-art device discloses a technique wherein a detector detects a
next zero-cross point of positive and negative peak points of an input
waveform signal, and a flip-flop is set/reset in response to each point
detection to generate a frequency signal corresponding to a pitch.
(l) Japanese Patent Publication No. 61-51793 (published on Nov. 10, 1986),
applicant: Nippon Gakki Seizo Kabushiki Kaisha.
This patent is a publication of the invention (h), and has the same gist as
the content of the invention (i). That is, digital frequency data is
generated upon detection of a substantial coincidence between two adjacent
periods.
(m) Japanese Utility Model Publication No. 62-20871 (published on May 27,
1987), applicant: Fuji Roland Kabushiki Kaisha.
This is a Japanese publication corresponding to the invention (b), U.S.
Pat. No. 4,606,255.
(n) Japanese Patent Disclosure (Kokai) No. 61-26090 (disclosed on Feb. 5,
1986), applicant: Seikou Denshi Kougyo Kabushiki Kaisha.
This prior-art invention discloses a technique for detecting a pitch from
an input waveform signal, sequentially writing the detected pitch in a
memory, and obtaining accurate pitch data later by executing an arithmetic
operation.
(o) Japanese Patent Disclosure (Kokai) No. 62-163099 (disclosed on Jul. 18,
1987), applicant: Fuji Gen Gakki Seizo Kabushiki Kaisha.
This prior-art invention relates to a guitar controller for a guitar
synthesizer, wherein frequency changing methods are switched in accordance
with monophonic or polyphonic tones generated. More specifically, when a
monophonic tone is generated, a picked-up vibration period is continuously
reflected to determine the frequency of the musical sound to be generated.
When a polyphonic tone is generated, the vibration period is reflected at
chromatic scale steps to determine the same.
Furthermore, the following U.S. patent applications disclosing an
electronic stringed instrument and a relating electronic equipment thereto
associated with the present invention assigned to the present assignee
have been filed.
(p) U.S. Ser. No. 112,780 (field on Oct. 22, 1987), inventor: Uchiyama et
al.
This prior-art invention discloses a technique for measuring a time period
between positive and negative peak points or between zero-cross points
associated with these peak points to extract a pitch of an input waveform
signal based on the measured time period, and a technique for performing
various control operations in accordance with the obtained pitch.
(q) U.S. Ser No. 184,099 (filed on Apr. 20, 1988), inventor: Iba et al.
In this prior-art invention, a musical tone parameter such as a timbre is
designated by a fret operation and a picking operation of a string. In
order to detect an operated fret, a pitch extraction technique, and a fret
switch detection technique is used.
(r) U.S. Ser. No. 256,398 (filed on Oct. 7, 1988), inventor: Iba et al.
This prior-art invention discloses a technique for performing musical tone
generation control in units of strings, changing characteristics of an
output musical tone in accordance with a plucking strength of a string, or
controlling an effector or pan (sound localization).
(s) U.S. Ser. No. 252,914 (filed on Oct. 3, 1988), inventor: Uchiyama
In this prior-art invention, a pitch extraction circuit comprising a
digital circuit in place of a conventional analog circuit, and integration
of the electronic circuit can be facilitated.
(t) U.S. Ser. No. 256,400 (filed on Oct. 11, 1988) Inventor: Matsumoto
This prior-art invention discloses an electronic apparatus for extracting a
pitch from an input waveform signal and generating a musical tone having
the corresponding tone pitch, and discloses a technique for changing a
tone pitch of an output tone along with a change of the input waveform
signal in pitch without accompanying an unnecessary variation in interval.
(u) U.S. Ser. No. 282,510 (filed on Dec. 9, 1988), inventor: Obata
In this prior-art invention, even if a pitch is unstably extracted at the
beginning of tone generation, a musical tone having a stable pitch can be
generated from the beginning. Start of musical tone generation is
chromatically instructed on the basis of a pitch extracted by a pitch
extraction system.
(v) U.S. Ser. No. 290,981 (filed on Dec. 28, 1988), inventor: Murata et al.
In this prior-art invention, strings are completely electronically tuned.
Before a performance, a reference pitch is determined by plucking at a
specific fret, and a tone pitch of a musical tone to be generated is
determined on the basis of period data obtained by plucking at a
designated fret using the reference pitch.
(w) U.S. Ser. No. 329,418 (filed on Mar. 27, 1989), Inventor: Obata
In this prior-art invention, a signal intensity of an input waveform signal
at its leading edge and a variation ratio of the signal intensity are
detected and tone volume or timbre of a musical tone can be independently
controlled in accordance with the two parameters. This technique, for
example, in an electronic stringed instrument, allows to change only
timbre of the musical tone without changing its tone volume by shifting a
string plucking position.
(x) U.S. Ser. No. 362,830 (filed on Jun. 7, 1989) inventor: Katou
In this prior-art invention, characteristics of a musical tone, such as
timbre, tone volume, tone pitch and the like are controlled on the basis
of variation in a pitch frequency and thereby an abundant performance
expression is realized.
As described above, according to the conventional technique, the form of
the tone volume envelope of a musical tone to be generated is previously
determined by selection of timbre of the musical tone and remains the
same. Only the level of the whole tone volume envelope changes depending
on the amplitude level of the input waveform signal at the leading edge.
Therefore, for example, even when a guitar operation is performed to
abruptly change the envelope of the string vibration of an electronic
stringed instrument, the envelope of a musical tone is determined
regardless of the above guitar operation. Accordingly, a performance
effect desired by the guitar player can not be obtained and the above
guitar operation can cause sound offensive to the ear.
When the player plucks a string of an electronic musical instrument, the
envelope of the string vibration has a characteristic shown at A in FIG.
1A, and the envelope of the musical tone to be generated has a
characteristic shown at B in FIG. 1A. In FIG. 1A, a symbol "ON" indicates
a timing at which sound generation of a musical tone is started when the
level of the string vibration shown at A in FIG. 1A exceeds a
predetermined value. Similarly, a symbol "OFF" indicates a timing at which
an instruction to stop sounding is given when the level of the string
vibration shown at A in FIG. 1A becomes equal to or less than a
predetermined value. That is, the envelope of the musical tone to be
generated decreases gradually after the OFF timing.
In this case, when the player performs a muting operation to compulsorily
cease the string vibration by holding the string with the palm of his
hand, while the string vibration has not adequately decreased after the
string is plucked, the envelope of the string vibration shows a
characteristic to rapidly decrease right after a strong attack, as shown
at C in FIG. 1B. On the other hand, the envelope of the musical tone to be
generated keeps an attenuating sound having considerable large volume for
a long time even after the OFF timing. Therefore, staccato sounds are not
generated and a unique nuance of the muting operation is lost.
Therefore, the following invention relating to other envelope control
technology has been developed.
(y) U.S. Ser. No. 370,336 (filed on Jun. 22, 1989), inventor: Uchiyama et
al.
In this prior-art invention, an envelope of a musical tone to be generated
can be controlled in accordance with an envelope of an input waveform and
thereby an effect of the envelope of the input waveform is further
imparted to a predetermined peculiar effect of the envelope of the musical
tone.
When the player of, for example, an electronic guitar performs the muting
operation to compulsorily cease the string vibration after plucking a
string, the whole envelope of the input waveform signal is characterized
to rapidly decrease as shown at E in FIG. 1(C). Then, even though the
variation of the envelope of the musical tone signal output from the
musical tone generator has a characteristic as shown at F in FIG. 1C, the
variation of the envelope of the musical tone signal output from the
musical tone generator can be characterized by the tendency to abruptly
decrease as shown at G in FIG. 1C because of being multiplied by the
characteristic as shown at E in FIG. 1C. Thus, the performance effect by
the muting operation can be easily obtained, and the player can modify the
envelope of the musical tone as the expects by his operation of the
instrument.
However, the attack portion of the musical tone signal as shown at F in
FIG. 1C is also multiplied by the envelope of the input waveform signal as
shown at E in FIG. 1C. In general, the characteristic of the attack
portion of the musical tone includes important elements for defining
timbre and the like of a musical tone. As the attack portion of the
envelope characteristic is modified as shown at G in FIG. 1C as a result
of the multiplication, a fact that sound characteristics of the musical
tone originally generated from the musical tone generator peculiar to an
electronic musical instrument is modified, causes trouble.
Furthermore, when reflecting the envelop of the input waveform upon the
musical tone signal as shown at G in FIG. 1C, the musical tone signal is
multiplied by an extracted envelope data from the input waveform at the
same rate. Therefore, if the influence of the envelope of the input
waveform is too strong, the envelope of the musical tone signal changes
too abruptly. Otherwise, the envelope of the input waveform signal
scarcely affect the envelope of the musical tone signal to be generated.
Accordingly, the player cannot control an imparting level of the effect of
the envelope based on the input waveform signal at will, thereby he is
difficult to obtain a desired musical tone.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above
situation, and has as its first object to provide an electronic musical
instrument in which an envelope of a musical tone to be generated can be
controlled in accordance with an envelope of an input waveform without
destroying a characteristic of the musical tone peculiar to the electronic
musical instrument, thereby a performance effect as expected by a player
can be obtained.
The second object of the present invention is to provide an electronic
musical instrument in which an imparting level of the effect of an
envelope of an input waveform to a musical tone signal can be controlled
freely, thereby a performance effect as expected by a player can be
obtained.
That is, according to one aspect of the present invention, there is
provided an electronic musical instrument comprising envelope extraction
means for extracting an envelope signal of an input waveform signal,
musical tone signal generation means for generating a musical tone signal,
envelope control means for controlling to impart the envelope signal
extracted by said envelope extraction means to the musical tone signal
generated by said musical tone signal generation means from a
predetermined timing after a generation start of said musical tone signal.
Furthermore, according to another aspect of the present invention, there is
provided an electronic musical instrument comprising envelope extraction
means for extracting an envelope signal of an input waveform signal,
musical tone signal generation means for generating a musical tone signal,
envelope signal generation means for generating a preset envelope signal,
mixing means for mixing the envelope signal extracted from said envelope
extraction means and said preset envelope signal generated from said
envelope signal generation means at a desired mixing ratio, and envelope
control means for controlling an envelope of said musical tone signal
generated from said musical tone signal generation means in accordance
with a mixed envelope signal obtained by said mixing means.
More specifically, the electronic musical instrument of the present
invention is realized as an electronic guitar and the like in which a
string vibration is detected as an input waveform by a sensor or a pickup
and a musical tone is controlled on the basis of the detected input
waveform.
The envelope extraction means is preferably realized by a combination of
the following means: maximum peak value detection means for detecting a
maximum peak value of a digital waveform signal at its leading edge, which
signal is obtained by digitizing an input waveform signal, effective peak
value detection means for sequentially detecting effective peak values of
said digital waveform signal after its leading edge, and envelope signal
calculation means for sequentially calculating means values of an
effective peak values sequentially detected by said effective peak value
detection means and the previous or preceding effective peak values, and
for sequentially outputting the mean values as the envelope signal.
As the musical tone generation means, various types of means such as a
digital sound source means and an analog sound source means can be
employed. For example, the musical tone generating means employing digital
circuits may be realized by a combination of the following means: memory
for storing a digital musical tone waveform, waveform read out means for
reading out digital musical tone waveforms from said memory at address
intervals corresponding to a sound pitch on the basis of an instruction
for starting sound generation and a sound pitch control, and sound
generation means for converting the read-out digital musical tone waveform
signal to an analog waveform signal, and for generating sound based on the
amplified analog waveform signal. In addition to this, a waveform
generation may be effected by employing technique such as a sine wave
synthesis, a frequency modulation (FM), a phase modulation and the like.
The envelope control means, for example, controls the envelope of the
musical tone signal generated from the musical tone signal generation
means in accordance with an envelope signal extracted by said envelope
extracting means from a predetermined timing after the starting of the
musical tone signal generation. The envelope control means may be realized
by multiplying means for multiplying the musical tone signal generated
from the musical tone signal generation means by values of the ratio which
are sequentially obtained by dividing the envelope values calculated by
the envelope signal calculation means after the predetermined timing is
passed, by the envelope value at the predetermined timing. In this
arrangement, a value, for example, 1.0 is multiplied by said multiplying
means, so that the musical tone signal is not modified.
In above construction, the musical tone signal generation means may include
an envelope generation means for imparting an envelope character such as
attack, decay, sustain, release and the like, to the musical tone signal
generated, and means for setting as said predetermined timing, a timing
when the envelope characteristic imparted by the envelope generation
means, is changed into the sustain phase.
As described above, according to one aspect of the present invention, when
a musical tone signal is generated from a musical tone generation means,
the musical tone generation means generates a musical tone signal without
modifying in an attack portion prior to a predetermined timing (e.g.,
sustain starting point), thereby keeping characteristics of a musical tone
such as timbre. In general, a sound starting portion (i.e., attack
portion) of a musical tone has an important element for defining
characteristics of the musical tone, such as timbre and the like.
Therefore the musical tone signal generation means outputs the musical
tone signal as it is so that the characteristics thereof may be
maintained.
After the predetermined timing, an envelope control means controls an
envelope of a musical tone signal generated from the musical tone signal
generation means in accordance with an envelope signal extracted from an
input waveform signal.
Accordingly, when the player of, for example, an electronic guitar performs
the muting operation to compulsorily cease the string vibration after
plucking a string, the timbre of a musical tone signal (synthesizer sound)
is maintained in an attack portion immediately after the start of
sounding. Thereafter, the envelope control means imparts an envelope
characteristic of the input waveform signal which is abruptly decreasing
in accordance with the muting operation to the musical tone signal and
thereby the player can change the envelope of the musical tone as he
expects by his operation of the instrument.
Furthermore, according to another aspect of the present invention, there is
provided a mixing means for mixing an envelope signal of an input envelope
waveform signal which is extracted by an envelope extracting means, and a
preset envelope waveform signal which is generated from an envelope signal
generation means at a desired mixing ratio. The mixing means, for example,
is realized by a combination of the following means: first multiplying
means for multiplying an envelope signal of the input waveform signal
extracted by an envelope extracting means by a first preselected and
desired factor, second multiplying means for multiplying a preset envelope
signal generated from the envelope signal generation means by a second
preselected and desired factor, and adding means for adding the outputs
from the first and second multiplying means to generate a mixed envelope
signal. The mixing ratio can be set by manual operation of a user, or
automatically set in accordance with timbre selection. The mixing ratio
may be changed in accordance with a pitch or note range of the musical
tone, and may be changed time-dependently. Further modification may be
realized as to the mixing means.
An envelope control means is further provided for controlling an envelope
of a musical tone signal generated from a musical tone generation means in
accordance with the mixed envelope signal obtained by the mixing means.
The envelope control means is, for example, realized as a multiplying
means which multiplies the musical tone signal generated from the musical
tone generation means by the mixed envelope signal.
In an electronic stringed instrument, an envelope signal derived from the
envelope extracting means directly corresponds to an envelope
characteristic of an input waveform signal which is changed on a real time
basis in accordance with a vibration of a string plucked by a player.
On the other hand, the preset envelope signal generated by the envelope
signal generation means has an envelope characteristic of, for example, a
synthesized sound which is preset by a user.
The mixing means mixes two kinds of the envelope signal at a desired ratio
to output a mixing envelope signal.
The envelope control means controls the envelope of the musical tone signal
generated from the musical tone signal generation means based on the mixed
envelope signal obtained as explained above.
Accordingly, a player of, for example, an electronic guitar can select the
mixing ratio of two kinds of the envelope signal previous to a musical
performance so that an envelope of the musical tone may be changed at a
plurality of steps between a preselected synthesizer sound envelope and an
envelope directly corresponding to a string vibration of an electronic
guitar.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and features of the present invention will be
apparent from the description of the preferred embodiment taken in
conjunction with the accompanying drawings, in which:
FIGS. 1A to 1C are charts showing disadvantages of conventional technique;
FIG. 2 is a block diagram showing the overall arrangement of first
embodiment of the electronic musical instrument according to the present
invention;
FIG. 3 is a block diagram of a pitch extraction digital circuit in FIG. 2;
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