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Description  |
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BACKGROUND OF THE INVENTION
One embodiment of the present invention relates generally to an automatic
play device such as a sequencer of a musical instrument, automatic
accompaniment device, automatic rhythm playing device or the like, and
more particularly to an automatic play device which can effectively
realize a smooth tempo change from one tempo to another corresponding to a
tempo change operation.
In Japanese Patent Laid-open Publication Nos. 58-211191 or 63-193192, there
is disclosed an example of a sequencer-type automatic play device of which
stores play data inputted from a keyboard of a musical instrument, a
computer or the like and reproduces a tone based on the stored play data.
In such an automatic play device, the play data is read out from a memory
in response to a tempo clock, and then a tone signal is generated based on
the read-out play data. The tempo clock frequency can be changeably
controlled in correspondence to a tempo setting value and thus the
reproduction play tempo can be freely changed to desired one. The tempo
setting value can be continuously changed by operating a tempo setting
knob, or it can be changed in response to a suitable switch operation.
However, the prior art automatic play devices are disadvantageous in that
when tempo change operation is made during the play by means of the tempo
setting operator such as the knob or switch, the tempo is caused to change
immediately and hence abruptly to a new tempo after the operation, which
inevitably gives an impression of awkward intermission. Further, in such
device that can continuously change the play tempo by the operation of the
tempo setting knob, it will become quite an obstacle to turn the knob
slowly during a manual play in an order to change the tempo smoothly.
Also, the aforesaid sequencers can be connected via MIDI terminals with a
MIDI musical instrument, and the automatic play tempo can be adjusted by
changing a tempo clock frequency of play data supplied from the sequencer
to the MIDI musical instrument connected in master-slave fashion
therewith. In a specific type of the sequencers, the tempo can be changed
in correspondence to the player's own beating time action; for example, in
the case where a pedal switch for adjusting a tempo is provided in the
sequencer, the player can control the automatic play tempo by stepping on
the pedal switch at a desired tempo (hereinafter, this step-on operation
will be called a tap). In this case, the sequencer detects when the pedal
switch is stepped on (switched on), and at each time of detection, it
changes a timing clock frequency in accordance with the time interval
between the times of the current and last step-on operations of the pedal
switch. However, in such sequencer, since the play tempo is determined in
correspondence to the tap interval, the music play is undesirably caused
to stop if the player stops tapping. Thus, the sequencer is not
satisfactory in that the player must continue to tap for every beat. Also,
it is substantially impossible to carry out ritardando, accelerando or the
like since the tap tempo change tends to cause the timing clock to
abruptly change in uncontinuous manner, which results in unnaturality of
music.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an automatic
play device which, when operation for changing an automatic play tempo is
effected, can change the tempo gradually and smoothly from one tempo to
another corresponding to the change operation.
It is a further object of the present invention to provide an automatic
play device which can realize a natural tempo change even when a tap is
effected only at a desired beat and which can control stopping and
restarting an automatic play in correspondence to a tap operation.
An automatic play device according to the present invention comprises a
tempo signal generating section for generating a tempo signal at a
frequency corresponding to a tempo setting value, an automatic tone
generating section for automatically generating a tone in accordance with
a tempo determined by said tempo signal, and a tempo change controlling
section for, when change of the tempo setting value is effected, gradually
changing a frequency of the tempo signal generated by the tempo signal
generating section, from one frequency to another in correspondence to the
change of the tempo setting value.
The tempo signal generating section generates the tempo signal at a
frequency corresponding to the tempo setting value. This tempo setting
value, as conventionally known, may be given in either of analog form or
digital numerical value by operating an operator such as a knob or a
switch or by other data input device. When this tempo setting value is
changed, the tempo change controlling section controls the frequency of
the tempo signal generated by the generating section in such manner that
the frequency may be changed gradually, from one frequency corresponding
to the tempo setting value not yet changed to another frequency
corresponding to the tempo setting value already changed. In this way,
when the tempo setting value is changed, the automatic play tempo does not
immediately or abruptly change to a desired tempo, but instead, it does
change gradually from one tempo to another tempo in correspondence to the
tempo setting value change, with the result that a smooth tempo change can
be effectively realized.
Further, an automatic play device according to the present invention
prestores play data in a memory section and reads out the play data in a
music procession order for automatic play, and it comprises a switch
section that is operated for beating time, a detecting section for
detecting when duration of a switch-on state of said switch section
exceeds a predetermined time, and a adjusting section for stopping the
automatic play at a next beat of the play data in response to detection by
said detecting section. The device further includes a measuring section
for measuring a measurement time until the switch section turns to the
next switch-on state, and a tempo adjusting section for, when the
measurement time is measured, changing the tempo in accordance with the
measurement time and thereafter maintaining the tempo until a new
measurement time is measured.
The detecting section detects when duration of the switch-on state of the
switch section exceeds the predetermined time, and the adjusting section
stops the automatic play at the next beat of the play data in response to
detection by the detecting section, so that the automatic play can be
automatically stopped. Also, the tempo adjusting section changes the tempo
in accordance with the measurement time and thereafter maintains the tempo
until a new measurement time is detected, so that a natural tempo change
can be realized.
Now, embodiments of the present invention will be described with reference
to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings,
FIG. 1 is a block diagram showing an embodiment of the invention;
FIG. 2 is a block diagram showing a hardware construction of an embodiment
of a musical instrument according to the invention;
FIG. 3 shows example data format of play data to be stored in a sequencer
memory in FIG. 2, expressed in accordance with the MIDI standard;
FIGS. 4A and 4B show a concept of tempo change processing of the invention;
FIG. 5 is a flow chart showing an example of a main routine performed by a
CPU shown in FIG. 2;
FIG. 6 is a flow chart showing a detailed example of a tempo setting event
process shown in FIG. 5;
FIG. 7 is a flow chart showing a detailed example of a preset/manual
setting event process shown in FIG. 5;
FIG. 8 is a flow chart showing a detailed example of a tempo change
coefficient setting event process shown in FIG. 5;
FIG. 9 is a flow chart showing a detailed example of a tempo followability
setting event process shown in FIG. 5;
FIG. 10 is a flow chart showing a detailed example of a play switch event
process shown in FIG. 5;
FIG. 11 is a flow chart showing a detailed example of a key-on event
subroutine shown in FIGS. 10 and 14;
FIG. 12 is a flow chart showing a detailed example of a time interval
setting subroutine shown in FIGS. 10 and 14;
FIGS. 13 and 14 is a flow chart showing an example of a tempo clock
interruption process;
FIG. 15 is a flow chart showing a modification of the tempo setting event
process shown in FIG. 6;
FIG. 16 is a flow chart showing a modification of the tempo followability
setting event process shown in FIG. 9;
FIG. 17 is a flow chart showing a modification of the tempo clock
interruption process shown in FIG. 13;
FIG. 18 is a block diagram showing a hardware construction of another
embodiment according to the invention;
FIG. 19 is a flow chart showing an example of a main routine performed by a
CPU shown in FIG. 18;
FIG. 20 is a flow chart showing an example of an event routine performed in
FIG. 19; and
FIGS. 21 and 22 show an example function of an embodiment shown in FIGS.
18-20.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 generally illustrates a fundamental construction of an embodiment of
an automatic play device according to the present invention. The device
generally comprises a tempo signal generating section 101 for generating a
tempo signal at a frequency corresponding to a tempo setting value, an
automatic tone generating section 102 for automatically generating a tone
in accordance with a tempo determined by the tempo signal, and a tempo
change controlling section 103 for, when change of the tempo setting value
is effected, gradually changing a frequency of the tempo signal generated
by the tempo signal generating section 101, from one frequency to another
in correspondence to the change of the tempo setting value.
FIG. 2 illustrates an embodiment of an automatic play device of the
sequencer type. A microprocessor unit (CPU) 10 is provided for performing
controls of the entire automatic play device. To this CPU 10 are connected
via a bus 19 a program and data memory 11, a working register 12, a
sequencer memory 13, an operation panel 14, an input-output device 15, and
a tempo clock generator 18. In this embodiment, the components indicated
by reference characters 10-15, 18 and 19 constitute a sequencer module, to
which modules of a keyboard 16 and a tone source 17 are connected via the
input-output device 15. The data exchanges among individual modules are
done in accordance with the well-known MIDI (Musical Instrument Digital
Interface) standard.
The program and data memory 11 stores various programs and data to be used
by the CPU 10, and it comprises a read only memory (ROM). The working
register 12 is provided for temporarily storing various data generated
when the CPU 10 carries out the programs, and predetermined address areas
of a random access memory (RAM) are reserved as this register 12. The
sequencer memory 13 comprises a random access memory (RAM) and stores play
data.
The operation panel 14 includes various kinds of operators for selecting,
setting or controlling tone color, tone volume, tone pitch, tone effects
or the like; for example, as a group of tempo setting operators, it has a
tempo setting operator 14a, a tempo change coefficient setting operator
14b and a tempo followability setting operator 14c, the tempo setting
operator 14a being used for setting a desired tempo.
The input-output device 15 is provided for implementing the input and
output of play data expressed in accordance with the MIDI standard. With
this device 15, the keyboard circuit 16 provided for inputting desired
play data into the sequencer module and also the tone source 17 that
receives play data outputted from the sequencer module can be connected.
Of course, for the purpose of inputting desired play data, a computer etc.
can be connected in place of the keyboard circuit 16.
The keyboard circuit 16 comprises a plurality of key switches that are
provided in corresponding relations with respective keys on a keyboard for
designating the tone pitch of a tone to be generated. The keyboard circuit
16 outputs key-on event data when a key has been newly depressed and
outputs key-off event data when a key has been newly released. The circuit
16 also performs a touch data generation process by determining the
velocity of key depression, the magnitude of key depression force or the
like, and it outputs thus generated touch data as velocity data. The
key-on, key-off and velocity data are expressed in accordance with the
MIDI standard and contain data indicative of a key code and an assigned
channel as described later.
The tone source 17, which is capable of generating tone signals
simultaneously in a plurality of channels, receives play data (data
prepared in accordance with the MIDI standard) and generates a tone signal
on the basis of this data. In the tone source 17, and any known system of
tone signal generation may be employed as required. Namely, the system may
be, for example, the memory read-out system in which tone waveshape sample
value data stored in a waveshape memory is sequentially read out in
accordance with address data that changes in correspondence to the tone
pitch of a tone to be generated, or, the FM system in which predetermined
frequency modulation operation is performed utilizing the abovementioned
address data as phase parameter data so as to obtain tone waveshape sample
value data, or, the AM system in which predetermined amplitude modulation
operation is performed utilizing the abovementioned address data as phase
parameter data so as to obtain tone waveshape sample value data. A digital
tone signal generated in the tone source 17 is converted to an analog tone
signal through a digital-to-analog converter (not shown) and is sounded by
a sound system (also not shown).
The tempo clock generator 18 generates a tempo clock pulse at a selected
frequency for counting a time interval or setting a tempo for automatic
play, and the frequency of the tempo clock pulse can be set and adjusted
by means of the tempo setting operators 14a, 14b, 14c. The tempo clock
pulse generated by the generator 18 is given to the CPU 10 as an
interruption signal so that an automatic play process can be carried out
by an interruption process.
Automatic play data to be stored in the sequencer memory 13 is data that
represents a play sequence. In the record mode, play data is sequentially
stored in the memory 13 in accordance with the player's actual playing,
while in the play mode, the stored data of the memory 13 is sequentially
read out in response to the abovementioned tempo clock. The play data to
be stored in the memory 13 is various data based on the events in the
keyboard circuits 16 and operation panel 14. To be more specific, the
sequencer memory 13 stores key-on event data when a keyboard key has been
newly depressed and stores key-off event data when a keyboard key has been
newly released, and also stores time data indicative of a time interval
between those events. The process for recording those automatic play data
is known and hence will not be described in detail.
The play data to be stored in the sequencer memory 13 is for example in the
data format of the MIDI standard. FIG. 3 illustrates examples of the
respective data formats of the key-on, key-off and time interval data. The
first byte of each data is a status byte (a byte utilized for an
identification code indicative of the nature of a message), and the
following second and third bytes are data bytes.
The first byte of the key-on data, namely, key-on event data is composed of
"9" representing key-on data and "X" indicating the number of the MIDI
channel to which the key-on event has been assigned, and thus the
identification code of this data is "9X". The first byte of the key-off
data, namely, key-off event data is composed of "8" representing the
key-off data and "X" indicating the number of the MIDI channel to which
the key-off event has been assigned, and thus the identification code of
this data is "8X". The second byte of each of the key-on and key-off data
indicates the key code of the key concerned, and the third byte indicates
velocity data which is the touch data of the key.
Although not defined in the MIDI standard, the identification code "F4" in
the first byte of the time interval data is used in the embodiment as an
identification code byte for the time interval indicating a timing at
which a tone is to be generated. The time interval is indicated by the
upper 7 bits of the second byte and the lower 7 bits of the third byte.
As set forth above, one unit of the event data or the time interval data
comprises three-byte data. In the sequencer memory 13, one address
designated by a pointer is used for one byte, so that one unit of the
event data or the time interval data comprising three-byte data is stored
in successive three pointer addresses.
In this embodiment, the sequencer memory 13 has a memory capacity of
thirty-two tracks. Each track corresponds to one play part, and tones can
be simultaneously generated in sixteen channels for each track. In other
words, one play part is a sixteen-channel polyphonic part. The channel "X"
in the first byte of the MIDI standard indicates one of the sixteen
channels within the MIDI. The sequencer memory 13 stores sequential play
data at each track, and reads out the stored play data of each track for
reproduction.
In this embodiment, when change of the tempo setting value is effected by
operating the tempo setting operator 14a, the tempo clock frequency is
caused to shift gradually from one frequency corresponding to the previous
(unchanged) tempo setting value, to another frequency corresponding to the
new (changed) tempo setting value.
Example manners how the frequency is shifted and interpolation is made in
the case will now be outlined with reference to FIGS. 4A and 4B, in each
of which the horizontal axis denotes time, and the vertical axis denotes
tempo clock frequency. In each of the figures, a case is illustrated where
the tempo clock frequency is first increased from A to B and then
decreased from B to C.
When operation has been made for increasing the tempo clock frequency from
A to B in FIG. 4A, namely, there has occurred a tempo setting event for
increasing the tempo by means of the tempo setting operator 14a, the tempo
clock frequency is increased by the tempo increase amount U0 at time T0 to
take the value of A+U0, this value of A+U0 being maintained for a unit
time interval Ea (between times T0 and T1). Next, at time T1, the tempo
clock frequency is increased by the tempo increase amount U1 to take the
value of A+U0+U1, and this value of A+U0+U1 being maintained for a unit
time interval Ea. After that, the increase amounts U2, U3, U4, U5 and U6
are likewise added to the tempo clock frequency as the time passes, and
thus the frequency is increased gradually until it reaches the target
tempo clock frequency B at time T6. In this example, the tempo increase
amounts U1, U2, U3, U4, U5, U6 are predetermined to become gradually
smaller in the order of mention so that the tempo clock frequency increase
follows a logarithmic curve.
After the desired tempo-up (tempo increase) is completed in the
abovementioned manner, the tempo clock frequency B is maintained at a
fixed value for a period between times T6 and T7. Subsequently, when there
has occurred at time T7 a tempo setting event for decreasing the tempo,
the tempo clock frequency is, in the reversed manner from the above,
decreased by the tempo decrease amount D0 at time T7 to take the value of
B-D0, this value of B-D0 being maintained for a unit time interval Eb
(between times T7 and T8). Then, at time T8, the tempo clock frequency is
decreased by the tempo decrease amount D1 to take the value of B-D0-D1,
this value of B-D0-D1 being maintained for a unit time interval Eb. After
that, the tempo decrease amount D2, D3, D4 and D5 are subtracted from the
tempo clock frequency as the time passes, and thus the tempo clock
frequency is decreased gradually unit it reaches the target tempo clock
frequency C at time T12. The tempo decrease amounts D1, D2, D3, D4 and D5
are determined so as to become gradually smaller in the order of mention.
The unit time interval Eb for the tempo decrease is determined to be
shorter than the unit time interval Ea for the tempo increase, and hence
the tempo clock frequency is decreased at a higher speed than when it is
increased. It means that the change rate at which the tempo is made faster
is smaller than the change rate at which the tempo is made slower.
Similarly, in the example shown in FIG. 4B, the tempo clock frequency is
caused to shift in the order of A, B, C, but a unit time interval Eb for
the tempo increase is equal to a unit time interval Eb for the tempo
decrease. Accordingly, if a tempo setting event occurs simultaneously at
time T0 and t0 respectively in both the examples of FIGS. 4A and 4B, the
target tempo clock frequency B can be reached earlier in the example of
FIG. 4B than in the example of FIG. 4A. Further, the respective tempo
decrease amounts D6, D7, D8, D9 in the example of FIG. 4B are
predetermined to become greater than the corresponding decrease amounts in
the example of FIG. 4A. Accordingly, if the decrease commences
simultaneously at time T7 and t7 in both the examples of FIGS. 4A and 4B,
the tempo block frequency C can be reached earlier in the example of FIG.
4B than in the example of FIG. 4A. It means that also in the example of
FIG. 4B, the change rate at which the tempo is made faster is smaller than
the change rate at which the tempo is made slower.
Thus, according to this embodiment, the change rate at which a certain
tempo clock frequency shifts to the target tempo clock frequency can be
variably set and the tempo clock frequency shift following a desired
change curve characteristic can be implemented, by predetermining as
desired the tempo increase and decrease amounts (those being hereinafter
referred to as tempo change amounts) or the unit time intervals for the
tempo increase and decrease. The unit time intervals Ea, Eb for the tempo
increase and decrease will be hereinafter referred to as tempo
followability, because the time required for the complete tempo shift,
namely, the tempo followability with respect to tempo clock frequency
changing operation is determined by controlling the lengths of such time
intervals. Specific processes in accordance with the tempo increase and
decrease amounts and the tempo followability will be described later.
Examples of various processes in the automatic play device of FIG. 2 that
are performed by the CPU 10 will now be described on the basis of flow
charts shown in FIGS. 5-15.
Before getting down to the point, the contents of the working register 12
will be described. The following registers are arranged in the working
register 12:
FLG: Identification code register that temporarily stores an identification
code in the first byte of a unit play data;
MD(TRK): Action mode register that stores, for each track, an action mode
currently selected from among a reproduction mode, record mode, stop mode
etc.;
POINT(TRK): Pointer that designates, for each track, an address of the
sequencer memory 13;
PRI: Process mode register that indicates whether the currently selected
process mode is a preset mode in which tempo change coefficient and tempo
followability data preset in the program and data memory 11 are used, or a
manual mode in which tempo change coefficient and tempo followability set
as desired by a user are used. This register stores "1" when the current
mode is the preset mode and stores "0" when the current mode is the manual
mode;
KCD: Key code register that temporarily stores a key code;
VEL: Velocity register that temporarily stores velocity data;
TNOW: Tempo setting register that temporarily stores tempo data for setting
a tempo clock frequency, namely, data indicative of the current tempo
setting value;
TNEW: Target tempo register that temporarily stores target tempo data
indicative of a target tempo for tempo change;
TRK: Track number register that designates the number (1-32) of a track
which is currently processed;
TIME(TRK): Time interval register that temporarily stores, for each track,
data indicative of a time interval between successive play events;
UPC: Tempo-up coefficient register that is used when the tempo clock
frequency is increased and stores a tempo-up coefficient for determining
the tempo increase amount set as desired by the user;
DNC: Tempo-down coefficient register that is used when the tempo clock
frequency is decreased and stores a tempo-down coefficient for determining
the tempo decrease amount set as desired by a user;
EU: Tempo-up followability register that stores tempo followability data
(for example, the unit time interval Ea or Eb of FIG. 4A or 4B) for the
tempo-up change set as desired by the user;
ED: Tempo-down followability register that stores tempo followability data
(for example, the unit time interval Eb of FIG. 4A or 4B);
EXU: Tempo-up time measuring register that stores the tempo followability
data in the tempo-up followability register EU to decrement the data;
EXD: Tempo-down time measuring register that stores the tempo followability
data in the tempo-down followability register ED to decrement the data;
and
EXPRI: Time measuring register that stores tempo followability data EPRI
prestored in the program and data memory 11 to decrement the data.
Further, in the program and data memory 11 are prestored such data as
tempo-up coefficient data UPCX and tempo-down coefficient data DNCX which
correspond, respectively, to the tempo-up coefficient stored in the
tempo-up coefficient register UPC and the tempo-down coefficient stored in
the tempo-down coefficient register DNC, and tempo followability data
which corresponds to the tempo followability data in the above mentioned
tempo-up and tempo-down followability registers EU, ED. The tempo
followability data stored in the program and data memory 11 is used in
common for both the tempo-up and tempo-down changes.
FIG. 5 shows an example of the main routine performed by the CPU 10.
Upon switch-on of the power, the CPU 10 start processes corresponding to
the control program stored in the program and data memory 11. In an
initialization process, the working register 12 is initialized. After the
initialization process, a play switch event process, a preset/manual
setting event process, a tempo change coefficient setting event process, a
tempo followability setting event process and other processes (i.e., other
operation event processes such as a record switch process, a stop switch
process and a ten key input process) are repeatedly performed in response
to the respective events.
The play switch event process is performed for starting an automatic play
(reproduction) when a play (reproduction) switch on the operation panel 14
has been operated. An example of the play switch event process is shown in
FIG. 10. The tempo setting event process is performed when operation to
change the tempo setting value has been made by means of the tempo setting
operator 14a on the operation panel 14. An example of the tempo setting
event process is shown in FIG. 6. The preset/manual setting event process
is performed when a process mode selecting switch on the operation panel
14 has been operated. An example of the preset/manual setting event
process is shown in FIG. 7. The tempo change coefficient setting event
process and the tempo followability setting event process are performed
respectively when operations to set the tempo change coefficient or
followability data have been made by means of the operators 14b, 14c on
the operation panel 14. Examples of these processes are shown in FIGS. 8
and 9. In the other processes, such processes based on operations of the
other operators on the operation panel 14 and various other processes are
performed.
In the tempo setting event process shown in FIG. 6, a tempo setting value
newly set by means of the tempo setting operator 14a is stored as target
tempo data in the target tempo register TNEW, the tempo followability data
of the tempo-up followability register EU and the tempo-down followability
register ED are stored in the tempo-up time measuring register EXU and the
tempo-down time measuring register EXD, respectively, and the tempo
followability data EPRI within the program and data memory 11 is stored in
the time measuring register EXPRI. With thus stored data, it becomes
possible to make the rates for the tempo-up and tempo-down changes
different from each other when the tempo change operations are made in the
manual mode.
In the preset/manual setting event process shown in FIG. 7, the contents of
the process mode register PRI is inverted to the preset mode or the manual
mode whenever the process mode selecting switch has been operated.
In the tempo change coefficient setting event process shown in FIG. 8, a
tempo change coefficient for the manual mode is set in the tempo-up
coefficient register UPC or in the tempo-down coefficient register DNC.
First, it is determined whether or not the setting event by means of the
tempo change coefficient setting operator 14b is a coefficient setting
operation directed to the tempo-up change. If the determination result is
YES, the tempo change coefficient set by the tempo change coefficient
setting operator 14b is stored into the tempo-up coefficient register UPC;
if, on the other hand, the result is NO, the set tempo change coefficient
is stored into the tempo-down coefficient register DNC.
In the tempo followability setting event process shown in FIG. 9, tempo
followability data for the manual mode is set in the tempo-up and
tempo-down followability register EU, ED. To do this, it is first
determined whether or not the setting event operation by the tempo
followability setting operator 14c is a followability setting operation
directed to the tempo-up change. If the determination result is YES, the
tempo followability data set by the tempo followability setting operator
14c is stored into the tempo-up followability register EU; if, on the
other hand, the result is No, the followability data is stored into the
tempo-down followability register ED.
As for the example of FIG. 4A, substantially same values are respectively
set in the tempo-up and tempo-down coefficient registers UPC, DNC in the
process of FIG. 8, and the unit time interval Ea is set in the tempo-up
followability register EU and the unit time interval Eb shorter than the
interval Ea is set in the tempo-down followability register ED in the
process of FIG. 9. Thus, in the example of FIG. 4A, although the tempo
increase amount for the tempo clock frequency increase and the tempo
decrease amount for the tempo clock frequency decrease are substantially
the same, the frequency increase takes place more slowly than the
frequency decrease due to difference in the time intervals
(followabilities).
As for the example of FIG. 4B, a smaller value than the value of the
tempo-down coefficient register DNC is set in the tempo-up coefficient
register UPC in the process of FIG. 8, and substantially same time
intervals Eb are respectively set in the tempo-up and tempo-down
followability register EU, ED. Thus, in the example of FIG. 4B, although
the unit time intervals are the same for the tempo clock frequency
increase and decrease, the frequency increase takes place more slowly than
the frequency decrease because the tempo increase amount is smaller than
the tempo decrease amount.
Individual steps of the play switch event process will now be described
with reference to FIG. 10.
Step 21: "1" is set in the track number register TRK to start processes for
the first track.
Step 22: It is determined whether or not the value stored in the action
mode register MD(TRK) is the one indicative of the reproduction mode. If
the determination result is YES, next step 23 is implemented; however, if
the determination result is NO (the value is indicative of the record or
stop mode other than the reproduction mode), step 30 is implemented. The
action mode register MD(TRK) is provided for each track, and in this step
22 the action mode of the track designated by the track number register
TRK is examined. A track to be reproduced can be designated as desired by
enabling an action mode to be set for each track in this manner, but
detailed explanation on the process for enabling an action mode to be set
for each track will be omitted.
Step 23: The head address of the sequencer memory 13 associated with the
track designated by the track number register TRK is stored into the
pointer POINT(TRK).
Step 24: Play data in the sequencer memory 13 corresponding to the address
indicated by the pointer POINT(TRK) is stored into the identification code
register FLG.
Step 25: The identification code of the play data stored in the
identification code is examined, and different steps are i | | |
