 |
Description  |
|
|
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a musical tone signal generating apparatus
which can be used for an electronic musical instrument, toys and the like,
and more particularly to a musical tone signal generating apparatus in
which a waveform signal is modulated such that a desirable musical effect
will be applied to a musical tone to be generated or so that the modulated
waveform signals are combined together into a new musical tone signal.
2. Prior Art
It is well known that the conventional apparatus modulates the musical tone
signal with the waveform signal having a low frequency in an amplitude
modulation, phase modulation, frequency modulation or the like, so that
the musical effect such as a tremolo, ensemble and the like can be
obtained. Or, this conventional apparatus circulatingly delays the musical
tone signal such that the reverberation effect or echo effect can be
obtained.
However, in the above-mentioned conventional apparatus, the modulation or
delay is monotonous so that the musical tone to be generated must be short
of the massiveness, thickness or depth in the music (hereinafter, referred
to as a musical thickness). Therefore, the listener may feel unsatisfied
with such musical tone.
SUMMARY OF THE INVENTION
It is accordingly a primary object of the present invention to provide a
musical tone signal generating apparatus capable of applying the variable
musical effect or the musical thickness to the musical tone to be
generated.
In a first aspect of the present invention, there is provided a musical
tone signal generating apparatus comprising:
(a) means for sequentially generating musical tone waveform data in lapse
of time, the musical tone waveform data consisting of first sampling data
indicative of instantaneous amplitude values of a continuous musical tone
waveform;
(b) first storing means for delaying the first sampling data outputted from
the means, so that the storing means sequentially stores delayed first
sampling data therein;
(c) acoustic converting means for converting an acoustic signal into an
analog signal, wherein the acoustic signal indicates acoustics of an
externally picked-up musical tone;
(d) analog-to-digital converting means for sequentially converting
instantaneous values of the analog signal into a digital signal by every
predetermined time;
(e) second storing means for sequentially storing the digital signal as
second sampling data indicative of the externally picked-up musical tone;
(f) multiplying means for multiplying each of the delayed first sampling
data and each of the second sampling data together; and
(g) combining means for combining output data of the multiplying means
together to thereby form an output musical tone waveform, the output
musical tone waveform being outputted from the combining means as output
sampling data indicative of instantaneous amplitude values thereof.
In a second aspect of the present invention, there is provided a musical
tone signal generating apparatus comprising:
(a) first means for sequentially generating first sampling data indicative
of instantaneous amplitude values of a first continuous musical tone
waveform in lapse of time;
(b) first storing means for delaying the first sampling data outputted from
the first means, so that the first storing means sequentially stores
delayed first sampling data therein;
(c) second means for sequentially generating second sampling data
indicative of instantaneous values of a second continuous musical tone
waveform;
(d) second storing means for delaying the second sampling data outputted
from the second means, so that the second storing means sequentially
stores delayed second sampling data therein;
(e) multiplying means for multiplying each of the delayed first sampling
data and each of the delayed second sampling data together; and
(f) combining means for combining output data of the multiplying means
together to thereby form an output musical tone waveform, the output
musical tone waveform being outputted from the combining means as output
sampling data indicative of instantaneous amplitude values thereof.
In a third aspect of the present invention, there is provided a musical
tone signal generating apparatus comprising:
(a) first means for sequentially generating first sampling data indicative
of instantaneous amplitude values of a continuous musical tone waveform in
lapse of time;
(b) first storing means for delaying the first sampling data outputted from
the first means, so that the first storing means sequentially stores
delayed first sampling data therein;
(c) acoustic converting means for converting an acoustic signal into an
analog signal, wherein the acoustic signal indicates acoustics of an
externally picked-up musical tone;
(d) analog-to-digital converting means for sequentially converting
instantaneous values of the analog signal into a digital signal by every
predetermined time, the digital signal being outputted as second sampling
data;
(e) second storing means for delaying the second sampling data, so that the
second storing means sequentially stores delayed second sampling data
therein;
(f) multiplying means for multiplying each of the delayed first sampling
data and each of the delayed second sampling data together; and
(g) combining means for combining output data of the multiplying means
together to thereby form an output musical tone waveform, the output
musical tone waveform being outputted from the combining means as output
sampling data indicative of instantaneous amplitude values thereof.
In a fourth aspect of the present invention, there is provided a musical
tone signal generating apparatus comprising:
(a) means for sequentially generating musical tone waveform data in lapse
of time, the musical tone waveform data consisting of first sampling data
indicative of instantaneous amplitude values of a continuous musical tone
waveform;
(b) storing means for delaying the first sampling data outputted from the
means, so that the storing means sequentially stores delayed first
sampling data therein;
(c) waveform storing means for storing second sampling data indicative of
instantaneous amplitude values of another musical tone waveform;
(d) multiplying means for multiplying each of the delayed first sampling
data and each of the second sampling data together; and
(e) combining means for combining output data of the multiplying means
together to thereby form an output musical tone waveform, the output
musical tone waveform being outputted from the combining means as output
sampling data indicative of instantaneous amplitude values thereof.
In a fifth aspect of the present invention, there is provided musical tone
signal generating apparatus comprising:
(a) means for generating musical tone waveform data in lapse of time, the
musical tone waveform data consisting of first sampling data indicative of
instantaneous amplitude values of a continuous musical tone waveform;
(b) storing means for delaying the first sampling data outputted from the
means, so that the storing means stores delayed first sampling data
therein;
(c) waveform storing means for storing second sampling data indicative of
instantaneous amplitude values of another musical tone waveform;
(d) operating means for operating each of the delayed first sampling data
and each of the second sampling data together; and
(e) tone forming means for forming a musical tone signal based on an output
of the operating means.
In a sixth aspect of the present invention, there is provided a musical
tone signal generating apparatus comprising:
(a) first means for sequentially generating first sampling data indicative
of instantaneous amplitude values of a first continuous musical tone
waveform in lapse of time;
(b) second means for sequentially generating second sampling data
indicative of instantaneous values of a second continuous musical tone
waveform;
(c) operating means for operating each of the delayed first sampling data
and each of the delayed second sampling data together; and
(d) tone forming means for forming a musical tone signal based on an output
of the operating means.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects and advantages of the present invention will be apparent
from the following description, reference being had to the accompanying
drawings wherein a preferred embodiment of the present invention is
clearly shown.
FIG. 1 is a circuit diagram showing a basic configuration for a convolution
operation control according to the present invention;
FIG. 2 is a block diagram showing an electronic musical instrument which
adopts the musical tone signal generating apparatus according to an
embodiment of the present invention;
FIG. 3 is a block diagram showing a detailed electric configuration of a
convolution operation circuit shown in FIG. 2;
FIGS. 4, 6, 8 and 9 show time charts which are used for explaining
operations of the electronic musical instrument shown in FIG. 2; and
FIGS. 5, 7, 10 and 11 show memory maps which are used for explaining
reading/writing operations of a memory shown in FIG. 2.
DESCRIPTION OF A PREFERRED EMBODIMENT
Next, description will be given to a preferred embodiment of the present
invention by referring to the drawings wherein like reference characters
are designated by like or corresponding numerals in the several views.
[A] BASIC CONFIGURATION FOR CONVOLUTION OPERATION CONTROL
First, description will be given with respect to the convolution operation
control which is used for an embodiment of the present invention.
FIG. 1 is a circuit diagram showing the electric circuit which is used as
the convolution operation control. This circuit shown in FIG. 1 consists
of n-stage circuits which include n pairs of delay circuits 1.sub.1,
1.sub.2, . . . , 1.sub.n and 2.sub.1, 2.sub.2, . . . , 2.sub.n, (n+1)
multipliers 3.sub.0, 3.sub.1, 3.sub.2, . . . , 3.sub.n, and n adders
4.sub.1, 4.sub.2, . . . , 4.sub.n.
The delay circuit 1.sub.1 inputs sampling data A(t) indicative of an
instantaneous value of a first continuous waveform signal which is taken
by every delay time dt (where d means delta .DELTA.). Each of the delay
circuits 1.sub.1, 1.sub.2, . . . , 1.sub.n delays its input signal by the
delay time dt, whereby these delay circuits 1.sub.1, 1.sub.2, . . . ,
1.sub.n output sampling data A(t-dt), A(t-2dt), . . . , A(t-ndt)
respectively. Another delay circuit 2.sub.1 inputs sampling data B(t)
indicative of an instantaneous value of a second continuous waveform
signal which is taken by every delay time dt. Each of the delay circuits
2.sub.1, 2.sub.2, . . . , 2.sub.n delays its input signal by the delay
time dt, whereby these delay circuits 2.sub.1, 2.sub.2, . . . , 2.sub.n
output sampling data B(t-dt), B(t-2dt), . . . , B(t-ndt) respectively. The
multipliers 3.sub.0, 3.sub.1, 3.sub.2, . . . , 3.sub.n multiplies the
sampling data A(t), A(t-dt), A(t-2dt), . . . , A(t-ndt) by B(t), B(t-dt),
B(t-2dt), . . . , B(t-ndt) respectively but inversely. Then, the adders
4.sub.1, 4.sub.2, . . . , 4.sub.n sequentially add the outputs of
multipliers 3.sub.0, 3.sub.1, 3.sub.2, . . . , 3.sub.n together to thereby
output an output signal C(t).
As a result, this output signal C(t) can be expressed as follows.
C(t)=A(t)*B(t-ndt)+A(t-dt)*B(t-(n-1)dt)+A(t-2dt)*B(t-(n-2)dt)+ . . .
+A(t-ndt)*B(t)
As described in the above formula, the output signal C(t) means the result
of the convolution operation between the inputs A(t) and B(t). For
example, the input A(t) can be set as the musical tone waveform signal
whose amplitude is continuously varied in lapse of time. In addition, when
each of the sampling data B(t-dt), B(t-2dt), . . . , B(t-ndt) is stored in
each of the delay circuits 2.sub.1, 2.sub.2, . . . , 2.sub.n, the
sequential delay operation (i.e., shift operation) of each sampling data
is stopped so that each sampling data is fixed to each delay circuit.
Thus, the musical tone waveform signal is applied with the modulation due
to the convolution operation based on the input B(t). Therefore, when the
impulse response waveform signal indicative of the reverberation
characteristic in the room is adopted as the input B(t), it is possible to
obtain the musical tone signal to which the reverberation characteristic
is applied. On the other hand, when another waveform signal is adopted as
the input B(t), it is possible to obtain the musical tone signal to which
the brand-new musical effect is applied.
Further, the waveform signal whose amplitude continuously varies in lapse
of time can be adopted as the input B(t), while the sequential delay
operation of the sampling data B(t-dt), B(t-2dt), . . . , B(t-ndt) at the
delay circuits 2.sub.1, 2.sub.2, . . . , 2.sub.n is continued. In such
case, the input A(t) as the musical tone waveform signal is dynamically
modulated by the convolution operation based on the input B(t). As a
result, it is possible to give the brand-new and complicated modulation
effect to the musical tone signal.
[B] CONFIGURATION OF AN EMBODIMENT
Next, description will be given with respect to the concrete configuration
of the musical tone signal generating apparatus according to the present
embodiment which is applied to the keyboard electronic musical instrument.
FIG. 2 is a block diagram showing the whole configuration of the keyboard
electronic musical instrument. This electronic musical instrument includes
a key switch circuit 12 consisting of plural key switches each
corresponding to each of plural keys in a keyboard 11. Each open/close (or
on/off) operation of the key switch in the key switch circuit 12 is
detected by a key-depression detecting circuit 13. In other words, this
circuit 13 detects depression/release operation of each key of the
keyboard 11. Thus, the circuit 13 outputs key information indicative of
the key which is depressed or released, and then this key information is
supplied to a main waveform data generating circuit 14 and a sub-waveform
data generating circuit 15.
Based on the key information, the main waveform data generating circuit 14
forms a first continuous musical tone waveform signal having a pitch
frequency of the depressed key in the keyboard 11. Then, this circuit 14
outputs sampling data indicative of the instantaneous value of the first
continuous musical tone waveform signal to a convolution operation circuit
16 as a waveform signal A. On the other hand, the sub-waveform data
generating circuit 15 forms a second continuous musical tone waveform
signal having the pitch frequency of the depressed key based on the key
information. Then, this circuit 15 output sampling data indicative of the
instantaneous value of the second continuous musical tone waveform signal
which is different from the waveform signal A, and this sampling data is
supplied to a first input ("1") of a selector 17. In order to form the
above-mentioned first and second continuous musical tone waveform signals,
it is possible to adopt several known methods such as the waveform memory
reading method, higher harmonic waveform combining method, operation
method and the like.
In addition, an analog-to-digital (A/D) converter 18 is connected to a
second input ("0") of the selector 17. The A/D converter 18 converts an
analog signal supplied from a microphone 21 into a digital signal, so that
the A/D converter 18 outputs this digital signal to the second input of
the selector 17 as sampling data indicative of the instantaneous value of
the tone which is externally picked up by the microphone 21 (hereinafter,
referred to as an external tone). The selector 17 selectively outputs one
of two sampling data to the convolution operation circuit 16 as a waveform
signal B based on a second mode signal MD2 which is supplied to a
selection control terminal SL thereof. When the second mode signal MD2
takes the value "1", the sampling data from the subwaveform data
generating circuit 15 is selected. On the other hand, when the second mode
signal MD2 takes the value "0", another sampling data from the A/D
converter 18 is selected.
This second mode signal MD2 is outputted from a mode selecting switch 22.
This mode selecting switch 22 also outputs first and third mode signals
MD1 and MD3. Based on the selecting operation of the mode selecting switch
22, any one of the mode signals MD1 to MD3 selectively takes the value
"1". In the present embodiment, these mode signals MD1, MD2 and MD3
respectively correspond to the following first, second and third modes
which are set in the keyboard electronic musical instrument.
(1) FIRST MODE
The impulse response waveform signal is inputted from the external device.
Then, the convolution operation is executed between this impulse response
waveform signal and the waveform signal A from the main waveform data
generating circuit 14 so that the output musical tone waveform signal is
formed. In addition, the convolution operation based on the pre-stored
waveform data whose waveform is fixed is executed so that the output
musical tone waveform signal is formed, wherein the impulse response
waveform data can be applied to this waveform data.
(2) SECOND MODE
The convolution operation is executed between the waveform signal A from
the main waveform data generating circuit 14 and another waveform signal B
from the sub-waveform data generating circuit 15 so that the output
musical tone waveform signal is formed.
(3) THIRD MODE
The convolution operation is executed between the waveform signal A and the
external tone signal from the microphone so that the output musical tone
waveform signal is formed, wherein the amplitude of waveform signal A may
continuously vary in lapse of time but the amplitude of external tone
signal may intermittently vary in lapse of time.
Next, under control of these mode signals MD1 to MD3, the convolution
operation circuit 16 executes the convolution operation between the
waveform signals A and B corresponding to the mode to be set, whereas the
detailed description of the convolution operation circuit 16 will be
described later. Thus, this circuit 16 generates a series of sampling data
each indicating the instantaneous value of the output musical tone
waveform. This sampling data is supplied to a digital-to-analog (D/A)
converter 23 as an output waveform signal C, wherein the sampling data is
converted into the analog signal which is to be supplied to a sound system
24. The sound system 24 comprises an amplifier, speaker and the like so
that it generates the musical tone corresponding to the analog signal
outputted from the D/A converter 23.
In addition to the above-mentioned elements, the present keyboard
electronic musical instrument further includes an impulse generator 25 and
a level detecting circuit 26 in order to generate the impulse signal and
also input the impulse response waveform signal into the convolution
operation circuit 16. Next, an AND circuit 28 inputs the first mode signal
MD1 and "1" signal to be supplied thereto via an operation switch 27 which
is used for generating the impulse, so that the output thereof is to be
supplied to the impulse generator 25. Thus, the impulse generator 25
outputs a pulse signal whose cycle is in synchronism with the leading edge
of the output of AND circuit 28. The impulse generator 25 is connected to
a speaker 32 via an amplifier 31. Therefore, the pulse signal from the
impulse generator 25 is converted into the acoustic signal, so that the
speaker 32 generates the sound corresponding to the acoustic signal.
Meanwhile, the A/D converter 18 is connected to the level detecting
circuit 26. When the level detecting circuit 26 detects that the output
signal level of the A/D converter 18 exceeds over the predetermined level
by inputting the external tone via the microphone 21, this circuit 26
outputs a pulse signal to a first input of AND circuit 33. In addition,
the output of AND circuit 28 is supplied to a second input of the AND
circuit 33. Thus, only when the impulse response waveform signal is
inputted into the present keyboard electronic musical instrument, the AND
circuit 33 supplies a sampling start signal SMPS to the convolution
operation circuit 16, wherein this sampling start signal SMPS consists of
the pulse signals each of which is in synchronism with the time when the
external tone (i.e., impulse response signal) is started to be inputted.
The present keyboard electronic musical instrument further comprises a
waveform data storing control circuit 34 in order to restore the waveform
data concerning the externally picked-up impulse response waveform signal
or use the predetermined waveform data for the convolution operation
instead of the waveform signal B in the convolution operation circuit 16,
wherein this circuit 34 controls the data transfer with the convolution
operation circuit 16. This circuit 34 is connected to the convolution
operation circuit 16 via a bus 35 which transmits a memory address signal
MADR, a memory read/write control signal MR/W and a memory enable signal
MEN. Based on these signals, the transfer of memory waveform data MDAT for
the convolution operation circuit 16 is controlled. The waveform data
storing control circuit 34 is connected with a waveform data memory 36
configured by a random-access memory (RAM). In addition, an external
storing unit 37 such as a magnetic disk unit or a magnetic tape unit can
be connected to the waveform data storing control circuit 34. Further, the
waveform data storing control circuit 34 is connected with a designating
unit 38 including plural operation switches. This designating unit 38
controls the read/write operation of waveform data for the waveform data
memory 36 and external storing unit 37.
Incidentally, a master clock signal Cm and a read/write control signal R/W
from the convolution operation circuit are supplied to several circuits
within the present keyboard electronic musical instrument according to
needs. In response to these signals Cm and R/W, the synchronizing
operation of each circuit is controlled.
Next, description will be given with respect to the detailed configuration
of the convolution operation circuit 16 by referring to FIG. 3.
The convolution operation circuit 16 as shown in FIG. 3 comprises: a first
waveform data storing portion WM1 for storing each of first sampling data
which form the waveform signal A; a second waveform data storing portion
WM2 for storing each of second sampling data which form the waveform
signal B; a calculation portion CAL for executing the convolution
operation; a timing control portion TMCON for controlling the operation
timings at the whole parts of the keyboard electronic musical instrument;
an address control portion ADCON for controlling the read/write operations
of each sampling data in the first and second waveform data storing
portions WM1 and WM2; and a sampling control portion SMPCON for
controlling the input of impulse response waveform signal.
The first waveform data storing portion WM1 includes a memory 41 consisting
of the RAM having N storing areas. A data input/output terminal DATA of
this memory 41 is connected to a bus 42, while a read/write control signal
R/W (see FIG. 4) from the timing control portion TMCON is supplied to a
read/write control terminal R/W thereof. When the signal R/W takes the
value "1", the reading operation of sampling data from the memory 41 is
controlled. When the signal R/W takes the value "0", the writing operation
of sampling data into the memory 41 is controlled. The input side of bus
42 is connected to a gate circuit 43 whose gate control terminal GC is
connected to an inverter 44. Therefore, an inverted read/write control
signal R/W is supplied to the gate control terminal GC of the gate circuit
43. When this inverted read/write control signal R/W takes the value "1",
the gate circuit 43 is turned on so that the first sampling data for the
waveform signal A is transmitted to the bus 42. On the other hand, the
output side of bus 42 is connected with another gate circuit 45. When the
read/write control signal R/W to be supplied to a gate control terminal GC
of the gate circuit 45 takes the value "1", the gate circuit 45 is turned
on so that the sampling data on the bus 42 is transmitted to the
calculation portion CAL. In addition, an output terminal of a selector 46
is connected to an address input ADR of the memory 41, wherein this
selector 46 is controlled by the read/write control signal R/W supplied to
a selection control terminal SL thereof. When the signal R/W takes the
value "0", the selector 46 selects a write address signal WADR from the
address control portion ADCON. When this signal R/W takes the value "1",
the selector 46 selects a review (or rewinding) read address signal READR
from the address control portion ADCON.
Similarly, the second waveform data storing portion WM2 includes a memory
47 consisting of the RAM having N storing areas. A data input/output
terminal DATA of this memory 47 is connected to a selector 48 whose
selection control terminal SL is supplied with a memory enable signal MEM
outputted from the waveform data storing control circuit 34 (see FIG. 2).
When this signal MEM takes the value "0", it is permitted that the
sampling data is transferred between the memory 47 and a bus 51. When this
signal MEM takes the value "1", it is permitted that the sampling data
(i.e., memory waveform data MDATA) is transferred between the memory 47
and the waveform data storing control circuit 34. The input side of bus 51
is connected to a gate circuit 52 whose gate control terminal GC is
supplied with an output of OR circuit 53. When the output of OR circuit 53
takes the value "1", the gate circuit 52 is turned on so that the second
sampling data for the waveform signal B is transmitted onto the bus 51.
The output side of bus 51 is connected to another gate circuit 54 whose
gate control terminal GC is supplied with an output of an inverter 55 to
which the output of OR circuit 53 is supplied. When the output of inverter
55 takes the value "1", the gate circuit 54 is turned on so that the
sampling data on the bus 51 is transmitted to the calculation portion CAL.
The first input of OR circuit 53 is supplied with an output of AND circuit
56. The inverted read/write control signal R/W from an inverter 57 is
supplied to the first input of AND circuit 56, while an output of OR
circuit 58 is supplied to the second input of AND circuit 56, wherein the
second and third mode signals MD2 and MD3 are supplied to the OR circuit
58. Therefore, when the second or third mode is set in the present
keyboard electronic musical instrument, the OR circuit 53 outputs the
inverted read/write control signal R/W. On the other hand, an output of
AND circuit 61 is supplied to a second input of the OR circuit 53. This
AND circuit 61 is supplied with the inverted read/write control signal
R/W, the first mode signal MD1 and a sample/hold signal S/H from the
sampling control portion SMPCON. In the first mode, the OR circuit 53
outputs the inverted read/write control signal R/W under the condition
where the sample/hold signal S/H takes the value "1".
Meanwhile, an output of a NOR circuit 62 is supplied to a read/write
control terminal R/W of the memory 47. The reading operation of this
memory 47 is controlled when the output of NOR circuit 62 takes the value
"1", while the writing operation thereof is controlled when it takes the
value "0". A first input of this NOR circuit 62 is supplied with an output
of AND circuit 63. The output of OR circuit 53 is supplied to a first
input of the AND circuit 63, while an output of inverter 64 is supplied to
a second input of the AND circuit 63. The memory enable signal MEN is
supplied to the inverter 64 so that an inverted memory enable signal MEN
is supplied to the second input of AND circuit 63. Due to the operations
of the NOR circuit 62 and AND circuit 63, when the memory enable signal
MEN takes the value "0", the inverted output of OR circuit 53 is supplied
to the read/write control terminal R/W of the memory 47. On the other
hand, an output of AND circuit 65 is supplied to a second input of the NOR
circuit 62. An output of inverter 66 is supplied to a first input of the
AND circuit 65, while the foregoing memory enable signal MEN is supplied
to a second input of the AND circuit 65. The memory read/write control
signal MR/W from the waveform data storing control circuit 34 (shown in
FIG. 2) is supplied to the inverter 66 so that the inverted memory
read/write control signal MR/W is supplied to the second input of AND
circuit 65. Due to the operations of the NOR circuit 62 and AND circuit
65, when the memory enable signal MEN takes the value "1", the inverted
read/write control signal MR/W is further inverted and then supplied to
the read/write control terminal R/W of the memory 47.
Next, an output of selector 67 is supplied to an address input terminal ADR
of the memory 47. This selector 67 is controlled by the memory enable
signal MEN supplied to a selection control terminal SL thereof, wherein
this memory enable signal MEN is outputted from the waveform data storing
control circuit 34 (shown in FIG. 2). The selector 67 selects an output of
selector 68 when the memory enable signal MEN takes the value "0", while
the selector 67 selects the memory address signal MADR from the waveform
data storing control circuit 34 when it takes the value "1". The selector
68 is controlled by the read/write control signal R/W supplied to a
selection control terminal SL thereof. This selector 68 selects the write
address signal WADR from the address control portion ADCON when the signal
R/W takes the value "0", while the selector 68 selects a forward read
| | |
