JP3231895B2 - Electronic musical instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, synthesizers,
The present invention relates to an electronic musical instrument such as an electronic piano, an electronic organ, and a sound source module, and more particularly to an electronic musical instrument that can change a sound effect based on a note-on range.

[0002]

2. Description of the Related Art In the case of an acoustic piano, a piano string is usually held down by a device called a damper which suppresses the vibration of the string. Vibrated and pronounced. When you play multiple keys, each string not only vibrates when struck by a hammer, but also resonates with each other's vibrations, producing a rich sound including resonance with the frame. And, the more keys are played at the same time, the greater the resonance effect becomes.

[0003] In the case of a conventional electronic musical instrument, when the number of keys pressed increases, musical tones corresponding to each depressed key are generated. However, they are simply added together and resonate with each other. Absent. In order to approximate the resonance effect of the acoustic piano, an effect circuit such as reverb may be used, but only a uniform effect set by a switch or the like on a setting panel is generated. That is, when the reverb effect switch is turned on, only a constant reverb effect is generated regardless of the number of keys pressed, so that a natural effect cannot be obtained.

In view of this, the applicant of the present application has filed Japanese Patent Application No.
No. 1242 proposes a device in which the number of key presses is counted, and the resonance effect is made variable by switching the control parameter value of the resonance circuit according to the number of key presses. In this case, a considerably natural effect was obtained as compared with the related art.

[0005]

However, in the case of an acoustic piano, the strings in the low range are often thick and long due to the winding, and the strings in the high range are thin and short in many cases. Also, no damper is attached to the highest range string,
It is always in the same state as the damper is away. Therefore, the degree of resonance greatly varies depending on the range of keys pressed, and simply changing the resonance effect according to the number of keys pressed results in a difference from a natural effect.

Accordingly, the present invention reflects the difference in the effect depending on the range of the key being depressed, and makes it possible to obtain an effect closer to that of an acoustic instrument. It is an object of the present invention to provide an electronic musical instrument capable of positively linking a difference in a sound range to a change in a sound effect and enabling a more varied performance.

[0007]

Means for Solving the Problems] Such an electronic musical instrument according to claim 1, wherein has been made in order to achieve the object, as illustrated in FIG. 1, sound a musical tone signal by the note-on, acoustic sound effect producing means The sound effect given to the tone signal can be changed by passing through M1, and an electronic musical instrument that performs only with its own device or in cooperation with an external device, and has a distribution corresponding to a key number that is turned on. Person in charge
Key press distribution measuring means M2 for accumulating numbers and calculating cumulative distribution coefficients;
Parameter value determination means M for determining a control parameter value Ri
3 and control means M4 for controlling the sound effect creating means M1 based on the parameter values determined by the parameter value determining means M3.

The electronic musical instrument according to a second aspect of the present invention, as exemplified in FIG. 2, further comprises a sounding channel counting means M5 for counting the number of note-on sounding channels in addition to the electronic musical instrument according to the first aspect. The parameter value determination means M3 calculates the number of sounding channels counted by the sounding channel counting means M5 and the cumulative distribution calculated by the key press distribution measuring means M2.
The control parameter value is determined by the number .

[0009]

According to the electronic musical instrument of the present invention having the above structure, the key press distribution measuring means M2 accumulates the distribution coefficient corresponding to the key number to which the note is turned on to calculate the cumulative distribution coefficient.
Out, and the parameter value determination means M3 is, note-on counter
The control parameter value is determined based on the data value and the cumulative distribution coefficient . When the control means M4 controls the sound effect sound creating means M1 according to the determined control parameter value, the sound effect sound to which the sound effect corresponding to the control parameter value is given is generated from the sound effect sound creating means M1. Is done. As the acoustic effect, various types of reverb (resonance), chorus, and the like can be considered.

Therefore, for example, if the predetermined correspondence between the cumulative distribution coefficient and the control parameter value is set in consideration of the relationship between the range of the acoustic piano and the degree of resonance, the effect of the range of the key being depressed can be obtained. By reflecting the difference, it is possible to obtain an effect closer to that of an acoustic piano. The same applies to various acoustic instruments as well as pianos. Further, the predetermined correspondence between the cumulative distribution coefficient and the control parameter value may be set irrespective of the relation between the range and the resonance degree in the acoustic piano. In addition to simply approaching an acoustic instrument, if the difference in the musical range being played is positively linked to a change in the sound effect, a more varied performance can be achieved.

Further, according to the electronic musical instrument of the present invention, the tone generation channel counting means M5 counts the number of note-on channels, and the parameter value determination means M3
Determines the control parameter value from the counted number of channels and the cumulative distribution coefficient calculated by the key press distribution measuring means M2.

Therefore, it is possible to obtain not only a difference in effect due to the range of the key being pressed but also a difference in the number of note-on channels (for example, a difference in the number of pressed keys) to obtain an effect closer to an acoustic instrument. it can. In this case, the weighting of the cumulative distribution coefficient and the number of note-on channels may be changed according to the acoustic instrument to be simulated. Also, a desired correspondence or weighting may be performed irrespective of the simulation of the acoustic musical instrument.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of the electronic musical instrument of the present invention will be described below. FIG. 3 is a block diagram showing the electrical configuration of the electronic musical instrument according to one embodiment.

The MIDI interface 10 controls the transfer of performance information transmitted and received between an external device (not shown) and the CPU 11. The external device referred to herein is one that supplies performance information to the electronic musical instrument or generates musical sounds based on performance information from the electronic musical instrument. For example, an MID such as an electronic piano, an electronic organ, and an electronic keyboard
An electronic musical instrument having an I interface function is used. The MIDI interface 10 is directly connected to the CPU 11 without passing through the system bus 12.

The CPU 11 controls each part of the electronic musical instrument according to a control program stored in a program memory of the ROM 17. The CPU 11 includes a system bus 1
2, the panel 13 and the pedal 15 are connected via the system bus 12, and the ROM 17 and the RAM 1 are connected via the system bus 12.
9, the touch sensor 21, the display panel unit 25, the musical sound generation unit 27, and the sound effect circuit 41 are connected.

The panel 13 includes various switches such as a power switch, a mode designation switch, a melody selection switch, a rhythm selection switch, a timbre selection switch (not shown), an effect setting switch 13a, and a reverb switch 13b. The set / reset state of each switch is detected by a panel scan circuit provided therein. Data on the switch set state detected by the panel scan circuit in the panel 13 is controlled by the CPU 11. It is stored in the RAM 19. Various information such as the current setting status of the switches on the panel 13 is displayed on the display panel unit 25.

The pedals 15 include, for example, a damper pedal, a soft pedal, a sostenuto pedal (all not shown) and the like according to the type of the electronic musical instrument. The CPU 11 controls the voltage according to the depression amount of the pedal 15 to control the volume. Or the attenuation characteristic is changed.

The ROM 17 stores tone color data and various other fixed data in addition to the program for operating the CPU 11 described above. The tone color data memory stores a frequency number, a waveform number, an envelope waveform number, mode data, and the like, which are data for synthesizing a tone vibration.

Each data stored in the tone data memory is specified by a tone point. That is, the timbre pointer is changed according to the panel operation and the keyboard operation, and each data specified by the changed timbre pointer is stored in the waveform memory 31 and the envelope waveform memory 33.
Is read from. Then, it is supplied to the tone generator 27 after a predetermined operation is performed.

The table for determining the attack speed, the attack level, the decay speed, the decay level, and the like, and the parameter value selection table are represented by R
OM17 is provided. On the other hand, the RAM 19 has a CP
U11 defines a work area, various registers, counters, flags, and the like for controlling the electronic musical instrument.
A data area in which necessary data stored in the OM 17 is transferred and stored, a plurality of registers in which data necessary for sound emission corresponding to the state of each switch of the panel 13 are set, and a tone generation unit are set to unused channels. It has an assignment memory for storing data to be assigned to the memory, a storage area for storing performance information, and the like.

The panel 13 stored in the RAM 19
The data regarding the setting state of the switch is referred to by the CPU 11 or the like as necessary at the time of sound generation. The key press map for storing the on / off state of the keyboard unit 23 and the note-on counter are also stored in the RAM 1.
9.

The keyboard section 23 is used for designating a musical tone to be generated, and is composed of a plurality of keys and key switches which are opened and closed in conjunction with key press / release operations of these keys. The touch sensor 21 detects the on / off state of the key switch and sends it to the CPU 11.

The tone generator 27 generates and outputs tone signals corresponding to various musical instruments by reading and reproducing the tone waveform data stored in the waveform memory 31. CPU 1 according to an input from keyboard unit 23
1 based on the control data output from
Reads out the tone waveform data and envelope data corresponding to the designated tone and volume from the waveform memory 31 and the envelope waveform memory 33, and outputs them as tone signals obtained by adding envelope data to the tone waveform data.

The output tone signal is divided into two systems, one of which is provided via a sound effect circuit 41 to a first D / A converter 47.
The other is supplied to the second D / A converter 47b without passing through the sound effect circuit 41. The sound effect circuit 41 outputs a sound effect sound by applying a predetermined sound effect to the tone signal sent from the tone generator 27 in accordance with the parameter control signal from the CPU 11.

Also, the tone generator 27 outputs the sound effect circuit 4
The digital tone signal output through 1 and through is converted into an analog tone signal by first and second D / A converters 47a and 47b and sent to first and second sound systems 49a and 49b, respectively. Supplied. Each of the sound systems 49a and 47b includes an amplifier and a speaker.
It is a well-known device that amplifies analog tone signals supplied from the A converters 47a and 47b with a predetermined gain, converts them into acoustic signals, and emits sound.

An adder for adding the tone signal output from the sound effect circuit 41 and the tone signal output through the tone generator 27 is provided, and one D / A converter and one sound system are provided. It may be one by one. next,
The operation of this embodiment will be described. FIG. 4 is a flowchart showing the general processing of this embodiment.

When the power supply is turned on, the CPU 11, the RAM 19,
Initialization of the sound source LSI and the like is performed. At S200, panel event processing is performed. At S300, pedal event processing is performed.
At S400, a keyboard event process is performed, and at S4
After the keyboard event process of 00, the process returns to S200 and the following processes are repeated. The following event processing S200, S30
0 and S400 will be described in detail.

First, the panel event process (S200)
This is a process related to the panel 13, and depending on the setting status (set / reset) of each switch on the panel 13, for example, turns on a corresponding LED, switches to a set tone, an automatic sound effect setting mode (effect setting). This is processing for switching to the reverb mode (when the switch 13a is pressed) or the reverb mode (when the reverb switch 13b is pressed).

Next, the pedal event process (S300) will be described with reference to FIG. This pedal event processing includes damper pedal processing (S310 to S350) and other pedal processing (S360). After the damper pedal processing is performed first, other pedal processing is performed.

First, at S310, it is determined whether or not a damper pedal ON event has occurred. If the damper pedal is newly depressed, that is, if there is an ON event (S310: YES), a flag indicating that the damper pedal has been turned on is set in the storage unit on the RAM 19 (S320), and the damper pedal process is performed. The processing ends, and the processing shifts to the next other pedal processing (S360).

On the other hand, if there is no on-event of the damper pedal in S310, it is determined whether or not there is an off-event of the damper pedal (S330). If an off event has occurred (S330: YES), the already set damper pedal on flag is reset (S340), and damper pedal off processing is performed (S35).
0). That is, the sound that has been extended while the keyboard is pressed and the damper pedal is depressed is silenced. After the process of S350, the process proceeds to another pedal process (S360).

If there is no event of turning off the damper pedal in S330, nothing is performed, and the process proceeds to other pedal processing (S360). The other pedal processing in S360 is, for example, soft pedal processing or sostenuto pedal processing, for example, setting / resetting a flag according to ON / OFF of an event, and sliding a variable resistor according to the degree of pedal depression. This is an operation of controlling the voltage by performing such operations.

Next, referring to the flowchart of FIG.
The keyboard event processing (S400) will be described. In the present keyboard event process, it is first determined whether or not an on event of the keyboard has occurred (S410). If an on event has occurred, a key pressing effect process (S420) is executed.

Here, the key pressing effect processing will be described with reference to the flowchart of FIG. First, the note-on counter is incremented (S421), and a key press distribution measurement process is performed (S422). This key press distribution measurement processing will be described later. In subsequent S423, the counter value and the cumulative distribution coefficient AL (described later) calculated in the key press distribution measurement processing are read, and the corresponding control parameter value is determined with reference to the parameter value selection table. In S424, the control parameter value is determined. Controls the sound effect circuit 41 to end this processing.

By the control in S424, the sound effect circuit 41 applies a predetermined sound effect (reverb, chorus or volume, etc.) based on the control parameter to the digital tone signal from the tone generator 27 to generate the sound effect sound. It is created and output to the first D / A converter 47a.

Returning to FIG. 6, following the key depression effect processing of S420, various musical tone parameters are loaded into the tone generator LSI (S420).
430). The musical tone parameters include, for example, an attack speed and an attack level indicating a rising speed and a magnitude, a decay speed and a decay level indicating a falling speed and a magnitude, a value of a reading (producing) frequency, and a start of reading a waveform memory. These are addresses and the like, which are loaded into the sound source LSI.

Thereafter, a sound generation process is performed (S440).
This keyboard event processing ends. That is, the CPU 11
Gives a tone generation instruction to the tone generator LSI. When the tone is generated by the tone generation process, a process for one keyboard event is performed. This process is repeated every time an event occurs.

On the other hand, if there is no ON event in S410, it is determined whether there is an OFF event (S450), and if there is an OFF event (S45).
0: YES), it is determined whether or not the damper is on (S460). If there is no off-event in S450 (S450: NO), that is, if there is no on-vent and no off-event, this keyboard event process ends without doing anything. If the damper is ON in S460 (S
(460: YES), the keyboard event processing is terminated without doing anything.

On the other hand, if a negative determination is made in S460, that is, if the damper is off, the release speed is read from the ROM 17 and loaded into the tone generator LSI (S470).
After performing the subsequent key release effect process (S480), the process ends.
This key release effect processing (S480) will be described with reference to FIG.

First, the note-on counter is decremented (S481), and a key press distribution measuring process (FIG. 9) described later is performed (S482). Then, the counter value and the cumulative distribution coefficient AL
Is read, the corresponding control parameter value is determined with reference to the parameter value selection table (S483), and the sound effect circuit 41 is controlled by the control parameter value (S4).
84) This process ends.

Next, the key press distribution measurement processing performed in S422 of the key press effect processing (FIG. 7) and S482 of the key release effect processing (FIG. 8) will be described with reference to the flowchart of FIG. In the key depression distribution measurement process, first, the distribution coefficient EL is loaded from the distribution coefficient table based on the key number at which the event occurred (S500). Here, the distribution coefficient table will be described with reference to FIG. In the present embodiment, the distribution coefficient EL is set to be large when the key number is small, that is, in the low-tone range, and to be small as the key number becomes large, that is, as the key number approaches the high-tone range. However, the distribution coefficient EL is set to be slightly larger in the highest range. This is because, in the case of an acoustic piano, a damper is not attached to the string in the highest range and the state is always the same as the state where the damper is separated, so that the state is simulated.

By setting this distribution coefficient table variously, the weighting by the key pressed area can be changed arbitrarily. In the example shown in FIG. 10, the length of the strings in the acoustic piano (becomes shorter as going from the lower range to the higher range) is considered from the low range to just before the highest range, and no damper is attached in the highest range. In consideration of the degree of resonance due to the strings, it is simulated as much as possible how each keyboard position on the acoustic piano affects the resonance effect.

Returning to FIG. 9, after the distribution coefficient EL is loaded in S500, if the key is pressed (S510: YES), the loaded distribution coefficient EL is added to the accumulated distribution coefficient AL (S520). The process ends. On the other hand, when the key is not depressed (S510: NO) but is released (S530: YE)
S), the loaded distribution coefficient EL is subtracted from the accumulated distribution coefficient AL (S540). If the cumulative distribution coefficient AL resulting from the subtraction is smaller than zero (S550: YES), AL =
0 (S560), terminates this process, and calculates the cumulative distribution coefficient A
If L is equal to or greater than zero (S550: NO), the process ends. Note that also in the case of a negative determination in S530 (that is, neither key depression nor key release), the process ends.

As described above, the cumulative distribution coefficient AL of this embodiment is
Simulates the case of an acoustic piano,
This reflects the degree of the resonance effect when the currently depressed range is produced. And S4 of FIG.
23 and S483 in FIG. 8, the control parameter value, that is, the tone signal sent from the tone generator 27 in the sound effect circuit 41 is referred to based on the counter value and the cumulative distribution coefficient AL with reference to the parameter value selection table. A parameter value for creating a sound effect sound by giving a sound effect to the sound effect is determined. A method of this determination will be described.

A control parameter value is determined based on a value obtained by performing a predetermined weighting on the counter value and the cumulative distribution coefficient AL. In this case, the counter value and the cumulative distribution coefficient A
The relationship between the value calculated by weighting L with a predetermined weight and the control parameter value is stored in the parameter value selection table, and is referred to. The counter value is not used as it is. For example, the number of key presses (or the number of sounding channels corresponding to the key presses) 1 to 3 is “1”, 4 to 7 are “2”, 8
The above can be considered to be classified into about three levels based on the condition of "3".

Further, the control parameter value may be determined by referring to the counter value corresponding to the divided cumulative distribution coefficient AL based on the cumulative distribution coefficient AL. The parameter value selection table in this case is such that, for example, when the counter value is 1 for a certain cumulative distribution coefficient AL,
In the case of 2 to 4, 5 to 7, 5 or more, it is conceivable to set individually according to the counter value based on the cumulative distribution coefficient AL.

The execution of the key press distribution measuring process shown in FIG. 9 corresponds to the process as the key press distribution measuring means M2 of the present invention, and the execution of the processes of S423 in FIG. 7 and S483 in FIG. This corresponds to the processing as the means M3. The execution of the processing of S424 in FIG. 7 and S484 of FIG. 8 corresponds to the processing as the control unit M4.

In the above embodiment, the counter value and the cumulative distribution coefficient AL are read in S423 of the key depression effect process (FIG. 7) and S483 of the key release effect process (FIG. 8), and the parameter value selection table is referred to. Although the control parameter value is determined, the control parameter value may be determined based only on the cumulative distribution coefficient AL. In that case, the increment processing of S421 of the key press effect processing (FIG. 7) and the decrement processing of S481 of the key release effect processing (FIG. 8) may be omitted.

In the above embodiment, the control parameter value is determined with reference to the parameter value selection table.
The control parameter value may be determined by executing a predetermined program process. Although it has been described above that the panel 13 is provided with the effect setting switch 13a and the reverb switch 13b, when one of these is pressed down and set, the other is automatically reset. The key setting effect process of S420 and the key release effect process of S480 in FIG.
3a is set and is executed in the automatic sound effect setting mode. On the other hand, when the reverb switch 13b is set, the key depression effect processing of S420 and the key release effect processing of S480 are not executed, and a uniform sound effect sound is created in the sound effect circuit 41 by a predetermined control parameter value. It will be.

As described above, according to the present electronic musical instrument, the key press distribution state is measured based on the key number of which the note is turned on, and the control parameter value is determined based on the cumulative distribution coefficient AL. Then, the sound effect circuit 41 generates a sound effect sound to which a sound effect according to the control parameter value is given. Therefore, in the case of the above embodiment, since the cumulative distribution coefficient AL is set in consideration of the relationship between the range of the acoustic piano and the degree of the sound effect, the difference in the effect due to the range of the key being pressed is reflected. An effect similar to that of an acoustic piano can be obtained.

By setting the same not only for the piano but also for various acoustic musical instruments, the sound can be produced with a closer feeling. Further, the correspondence between the cumulative distribution coefficient AL and the control parameter value may be set independently of the relationship between the range of the acoustic piano and the degree of the sound effect. In addition to simply approaching an acoustic instrument, if the difference in the musical range being played is positively linked to changes in various sound effects, a more varied performance can be achieved. For example, various settings can be made, such as applying a very deep reverb only when the highest range and the lowest range are played, or associating chorus and tremolo with a predetermined range. In this case, a variety of acoustic effects not found in ordinary acoustic instruments occur,
The range of performance expands.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various embodiments can be adopted without departing from the gist of the present invention. For example, in the above embodiment, the distribution coefficient table shown in FIG. 10 is set in consideration of the length of the strings so as to simulate an acoustic piano, but may be simply a linear change or a step-like change. A setting that changes may be used. Also,
The control parameters are not limited to those relating to one type of acoustic effect, and a plurality of control parameters may be set simultaneously.

Further, in the above embodiment, the number of key presses is counted and used for determining the control parameter value, but this may be the number of sound channels instead of the number of key presses. Depending on the model, a single key may use a plurality of channels, and the number of sound channels to be used may change depending on the tone setting (for example, piano, organ, harpsichord, etc.). Therefore, the number of sounding channels may be counted and used for determining the control parameter value.

[0054]

As described above in detail, according to the electronic musical instrument according to the first aspect, it corresponds to the key number that is turned on.
Accumulate distribution coefficient to calculate cumulative distribution coefficient , note
A control parameter value is determined based on the on-counter value and the cumulative distribution coefficient, and a sound effect sound with a sound effect corresponding to the determined control parameter value is generated. Therefore, for example, if the predetermined correspondence between the cumulative distribution coefficient and the control parameter value is set in consideration of the relationship between the range of the acoustic piano and the degree of the sound effect, the difference in the effect depending on the range of the key being pressed is different. And an effect closer to that of an acoustic piano can be obtained. Furthermore, it is not just an acoustic instrument,
If the difference in the musical range being played is positively linked to changes in various sound effects, a more varied performance can be achieved.

According to the electronic musical instrument of the present invention, the number of note-on sound channels is counted, and the number of sound channels and the cumulative distribution coefficient are counted .
It determines the control parameter value Ri. Therefore, it is possible to obtain an effect closer to that of an acoustic instrument by reflecting not only the difference in the effect depending on the range of the key being pressed but also the difference in the number of note-on sounding channels.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a basic configuration of an electronic musical instrument according to claim 1 of the present invention.

FIG. 2 is a block diagram illustrating a basic configuration of an electronic musical instrument according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing an electrical configuration of the electronic musical instrument according to one embodiment of the present invention.

FIG. 4 is a flowchart showing general processing of the embodiment.

FIG. 5 is a flowchart illustrating pedal event processing according to the present embodiment.

FIG. 6 is a flowchart illustrating keyboard event processing according to the present embodiment.

FIG. 7 is a flowchart illustrating a key pressing effect process according to the present embodiment.

FIG. 8 is a flowchart illustrating a key release effect process according to the present embodiment.

FIG. 9 is a flowchart showing a key press distribution measurement process.

FIG. 10 is an explanatory diagram illustrating a distribution coefficient table according to the present embodiment.

[Explanation of symbols]

M1: sound effect sound creating means, M2: key press distribution measuring means, M3: parameter value determining means, M4
... control means, M5 ... sounding channel counting means, A
L: cumulative distribution coefficient, EL: distribution coefficient, 10: MID
I interface, 13 ... panel, 13a ... effect setting switch, 13b ... reverb switch, 15 ...
Pedal, 21: Touch sensor, 23: Keyboard part,
27: musical tone generator, 31: waveform memory, 3
3: Envelope waveform memory 41: Sound effect circuit
47a, 47b ... D / A converter, 49a, 49b ...
Sound system

Continuation of the front page (56) References JP-A-4-204598 (JP, A) JP-A-60-91393 (JP, A) JP-A-4-121790 (JP, A) JP-A-2-131790 (JP) , U) Patent 2858120 (JP, B2)

Claims (2)

(57) [Claims] 1. A musical tone signal is generated by note-on .
And can vary the acoustic effect to be imparted to the tone signal by passing the acoustic sound effect producing means, an electronic musical instrument for performing play in cooperation with its own device only, or the external device, it is note-on Distribution coefficient corresponding to the key number
Key press distribution measuring means for accumulating and calculating a cumulative distribution coefficient ; parameter value determining means for determining a control parameter value based on the note-on counter value and the cumulative distribution coefficient; An electronic musical instrument, comprising: control means for controlling the sound effect creating means according to parameter values. 2. A sound channel counting means for counting the number of note-on sound channels, wherein the parameter value determining means includes a sound channel number counted by the sound channel counting means and a key press distribution measuring means. According to the calculated cumulative distribution coefficient
Electronic musical instrument according to the first aspect, characterized in that to determine the control parameter value Ri.