Electronic musical instrument

Abstract: A plurality of drum pads (l0) are each provided with a respective piezoelectric pick-up (ll). The out­ put of each piezoelectric pick-up (ll) is fed to a corre­ sponding envelope-extracting circuit (l3). The envelope signal extracted by the envelope-extracting circuit is converted by an A/D converter into a digital signal which is fed to a CPU (20). The CPU (20) feeds a tone designa­ tion signal to a tone genera-tor unit (27) according to parameter data from a parameter data setter (9) and the digital signals noted above, thereby causing generation of a corresponding drum sound.

Description: This present invention relates to an electronic musical instrument according to the preamble of claim 1. More particularly, the present invention relates to an electronic percussion instrument called an "electronic drum". Heretofore, various electronic musical instruments in the form of electronic drums have been developed. Such electronic drums are disclosed in US-A-3,551,580, US-A-3,553,339, US-A-3,956,959 US-A-4,418,598 and US-A-4,479,412. In any of these prior art electronic musical instruments, vibrations produced by striking a vibration member called a pad with a drumstick or a hand is converted by a pick-up or a transducer into an electric signal, and an amplifier is controlled for tone volume control according to this electric signal. This means that a circuit constituting the electronic drum performs analog signal-processing. This is unsatisfactory from the point of view of obtaining a variety of percussion instrument sounds; thus that kind of prior art electronic drums lacks flexibility. According to the preamble of new claim 1 the present invention starts out from a prior art as it is known from EP-A-0 142 390. This document discloses an electronic control circuit for an electro guitar which comprises two microphones (each of which consists of several individual microphone units), wherein the analog output signal of one of these microphones is coupled via an effective value detector to the input of an analog-to-digital converter. Furthermore, there is provided a CPU which receives a digitally sampled tonesignal representing an effective value of the input electric signal. Finally, there is provided a tone generating means in the form of an interface which is controlled by the CPU depending on the respective level of an analog signal which is compared by a comparator. A drawback of this known electronic musical instrument has to be seen in that it is rather difficult to reliably generate a tone which has a volume level or timbre corresponding to the magnitude of vibrations (detected maximum level) of the vibrating member. It is therefore the object of the present invention to improve an electronic musical instrument according to the preamble of claim 1 in such a way that a tone which has a volume level or timbre corresponding to the magnitude of vibrations can be reliably generated. According to the present invention this object is solved by the advantageous measures indicated in the characterizing part of claim 1. These advantageous features allow to generate the volume level or timbre of the respective tone very reliably. Further advantageous features of the present invention are subject-matter of the subclaims. In WO86/04718, which document constitutes a prior art in the terms of Art.54(3) EPC, there is disclosed an electronic musical instrument comprising analog signal generating means for generating an electric signal representing vibrations of a vibration member which is operative for a musical performance, tone generating means for generating a tone signal corresponding to the vibrations of that vibration member, control means for controlling the tone generating means by designating a characteristic of a desired tone depending on the respective level of the generated analog signal and analog-to-digital conversion means for converting the generated analog signal into a digital signal. In partial accordance with characterizing features of claim 1, this document furtheron discloses that the control means detects the levels of the digital signal for a predetermined number of times and designates the characteristic of the desired tone according to the result of this detection. This document, however, does not disclose the measure to detect a maximum level from among the detected levels of the digital signal. The document FR-A-2 555 347 discloses a further electronic instrument which comprises means for generating an analog signal which represents a musical performance, envelope extracting means (a diode in cooperation with an integrator) for extracting an envelope signal from the electric signal, tone generating means (an amplifier with adjustable gain, a low-pass filter and a preamplifier) for generating a tone signal corresponding to the a.m. envelope signal, and control means (in the form of a voltage controlled oscillator, a counter1, an adressable memory and a D-A-converter) for controlling the tone generating means. The invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: Fig. 1 is a schematic representation of an embodiment of the invention; Fig. 2A and Fig. 2B show, in combination, a parameter data set/display unit; Fig. 3A and Fig. 3B show, in combination, a flow chart illustrating the operation of a parameter setting; Fig. 4 is a flow chart briefly showing the operation of the musical instrument in play mode; Fig. 5 is a timing chart for explaining the operation for envelope extraction; Fig. 6A to Fig. 6C show, in combination, a flow chart illustrating a detailed operation while the instrument is in the play mode; and Fig. 7 is a view showing parameter data-designating tones generated in dependence on the state of a foot switch. Now, an embodiment of the invention will be described with reference to the drawings. Fig. 1 shows the overall circuit construction of an embodiment of the invention applied to an electronic percussion instrument. Elements 10 to 13 constitute an analog trigger signal generator, elements 14, 9 and 20 constitute a signal converter, and element 27 is a tone generator unit. In this electronic musical instrument, eight analog trigger-signal generators or lines L1 to L8 are used. As will be described later in detail, the signal converter can freely set such parameters as timbre, pitch, and channel to be allotted to the individual trigger-signal generators (i.e., the individual lines L1 to L8). At the time of performance, the performer plays eight drums, using drumsticks in eight lines L1 to L8. In consequence, analog trigger signals are generated from lines L1 to L8 and fed to the signal converter SC. The signal converter SC feeds a musical tone control signal to the tone generator unit 27 in a timing related to that of the generation of each analog signal. The tone control signals include key-on commands and tone volume level-designation data (these commands and designation data being determined through level analysis of the input signal) and also channel, timbre, and pitch designation data based on setting. The designated channel of the tone generator unit 27 is operated according to a tone control signal from the signal converter SC, whereby a tone signal of designated timbre, pitch, and tone volume is generated. The generated tone signal is sounded through a loudspeaker 28. Tone generator unit 27 can generate tone signals corresponding to the maximum number of tones to be produced at a time. It has a plurality of internal tone generation channels, which may be separate hardware channels or which can operate in a time-division multiplexing arrangement. In further detail, reference numeral 10 in each of lines L1 to L8 designates each drum pad. When drum pad 10 is struck by drumstick 12, its vibrations are picked up by piezoelectric pick-up 11, in order to be converted into an analog electric signal. Piezoelectric pick-up 11 may be replaced with a hall element or a mechanical-electric transducer, or a microphone. Further, it is possible to permit detection of the depression force rather than the vibrations of the drum pad. At any rate, the analog electric signal which represents vibrations of the drum pad is fed through a corresponding one of input terminals 1-1 to 1-8, to envelope-extracting circuit 13 of each lines L1 to L8. Envelope-extracting circuit 13 includes operational amplifier 16. Coupling capacitor 15 and grounded resistor 23 are connected to a non-inverted input side of operational amplifier 16, to cut a DC component in the non-inverted input. Diode 17 is connected to the output side of operational amplifier 16. The cathode of diode 17 is connected to a grounded time-constant circuit consisting of capacitor 18 and resister 19. The output of the cathode side of diode 17 is fed back to variable resistor VR, which can be adjusted by sensitivity adjustment volume control knobs 2 (see Fig. 2B) to the inverted input terminal of operational amplifier 16. The gain, and hence sensitivity, of operational amplifier 16 is thus determined by the resistance provided by variable resistor VR. The response characteristic is tentatively determined by the time-constant circuit. A/D converter 14 converts an envelope signal for 8 lines L1 to L8 provided from envelope-extracting circuit 13, into a corresponding digital signal. The conversion is effected in a timing related to the time-division processing of microcomputer 20 on input data on 8 lines L1 to L8. More specifically, microcomputer 20 drives 8 gates 24 constituting a multiplexer, on a time-division basis, and A/D converter 14 effects A/D conversion during a time slot during which each gate is held enabled by the gate control signals G1 to G8. More specifically, while line L1 is selected, microcomputer 20 enables gate 24 related to gate control signal G1 and produces an A/D conversion start signal commanding a conversion operation to A/D converter 14. In response to this signal, A/D converter 14 effects A/D conversion and, when this is completed, it sends an end signal back to microcomputer 20. In response to this end signal, microcomputer 20 fetches the converted data, and then selects line L2, i.e., the second analog trigger-signal generator, and enables gate 24 related to gate control signal G2, thus repeating the above operation. Microcomputer 20 is the center of the signal converter, and it includes ROM 26 where programs are stored; RAM 22 to store various data, for example, key-on command, key-off command code, tone volume designation code, timbre designation code, pitch (note) designation code, channel designation code, and also data fed from A/D converter 14; ALU 25 for excuting various arithmetic operations; and software timer 21 used for analysis of input data from A/D converter 14. The main function of microcomputer 20 is a data-setting (or edit) mode. In this mode, microcomputer 20 sets preset parameters from parameter set/display unit 9 which serves as an input/output unit in internal RAM 22, and also causes display of parameter data set in RAM 22 on parameter set/display unit 9. In the play mode, microcomputer 20 effects analysis of data fed from A/D converter 14 and provides a tone control signal to tone generator unit 27 according to the result of the analysis. Microcomputer 20, as described above, causes A/D converter 14, which is an interface for a plurality of (i.e., eight in this case) analog trigger-signal generators L1 to L8, to convert data for the individual signal generators and fetches the result of conversion. Now, the input data level analysis, which is performed by microcomputer 20 on a time-division basis, will be briefly described. Its details will be described with reference to Fig. 5 and Fig. 6. In the input data level analysis, microcomputer 20 determines the level of data fed from A/D converter 14 and, if the level exceeds a certain value (i.e., trigger level), it saves the input data in RAM 22. Subsequently, microcomputer 20 executes peak detection to detect the maximum value generated from the pertinent analog trigger signal generator. More correctly, a predetermined number of data subsequent to the trigger level are saved, and the strength of impact of drumstick 12 on drum pad 10 is estimated by finding out the maximum value. According to this maximum value, microcomputer 20 designates a tone volume level and feeds a key-on command to tone generator unit 27. Subsequently, microcomputer 20 continues to monitor the input data level. When the input data level becomes lower than a predetermined level, it starts timer 21. When time-out of timer 21 occurs with the input data level remaining lower than the predetermined level, microcomputer 20 feeds a key-off command to tone generator unit 27. At this time, data is transferred through MIDI (musical instrument digital interface). In this embodiment, microcomputer 20 feeds a key-on command together with various parameter data, to tone generator unit 27. The various data are of channel designation code, tone program designation code, and pitch designation code, these codes being set for each input data source. The channel designation code is a command for designating a channel to be used in tone generator unit 27. The timbre program designation code is a command for designating a timbre program to be used in the channel. The pitch designation code is a command for designating the pitch (i.e., note) of tone to be generated by tone generator unit 27. The above parameter data-setting is performed via parameter set/display unit 9 which serves as an input/output unit. The detailed construction of parameter set/display unit 9 will now be described with reference to Figs. 2A, 2B. Fig. 2B shows operating panel 9a on the front of the signal transducer, and Fig. 2A shows input/output terminal panel 8 on the back. Operating panel 9a corresponds to parameter set/display unit 9, and it includes part of the analog trigger-signal generator and the entirety of the signal converter. More specifically, envelope-extracting circuit 13, A/D converter 14, and microcomputer 20 are provided in the inside. Input/output terminal panel 8 has input terminals 1-1 to 1-8 to which signals from individual drum pads 10 are fed, and output terminal 6 from which a control signal is fed to tone generator unit 27. Reference numeral 2 designates sensitivity adjustment volume control knobs. For example, the resistance of feedback register VR of envelope extracting circuit 13 related to input terminal 1-1, is adjustable by operating the first control knob. Thus, the sensitivity with respect to the input signal from line L1, i.e., the first analog trigger-signal generator, is adjusted. Reference numerals 3 to 5 designate switch groups of various setting and selection switches. An LED is provided above each switch. When the LED is "on", it indicates that the corresponding switch is functioning correctly. Reference numeral 7 designates a display section which constitutes part of parameter set/display unit 9. Various data are displayed on the display surface of display section 7. Designated as 8-1 is an AC power source connector, and 9-1 is a power switch. In further detail, designated as 3-1 is a mode switch, which can switch the edit mode and play mode. When the LED of this switch is "on", it indicates the edit mode. Designated as 3-2 is a channel switch. When the LED of this switch is "on", it is possible to set a channel. The channel number can be set by operating up/down switches 3-5 and 3-6. Designated as 3-3 is a timbre program switch. When this switch is depressed once, timbre program selection is possible, and the corresponding LED is turned on. Designated as 3-4 is a pitch (note) switch. When the LED of switch 3-4 is "on", a note can be set, using keys 3-5 and 3-6. Designated as 4 is a switch group for selecting each line (i.e., each analog trigger-signal generator). In this embodiment, there are eight input lines, so that eight line switches 4-1 to 4-8 are provided. For example, when effecting parameter data-setting with respect to line L1, i.e., the input line connected to input terminal 1-1, line L1 is selected by depressing key 4-1. Thus, channel designation code data, timbre program designation code data, and pitch designation code data are stored in RAM 22 in microcomputer 20, such that these data are allotted to the eight lines and can be accessed independently. Microcomputer 20 further has four programmable areas each with an eight-line data set, and these areas are selected by system selection switches 5-1 to 5-4. More specifically, the 8-line data for the first set is selected by depressing switch 5-1, the data for the second set by depressing switch 5-1, the data for the third set by depressing switch 5-3, and the data for the fourth set by depressing switch 5-4. The data group for each set corresponds to an electronic musical instrument system. That is, when a data group for a particular set is used at the time of performance, an electronic musical instrument system is operated. This means that the present embodiment has four electronic musical instrument systems, that is, four sets of tones generated by operating drum pads 10 are programmable prior to the performance. It is to be understood that parameter data can be freely set and altered by operating the switches of groups 3 to 5. A system is selected by using switch group 5; a line in the same system is selected by using switch group 4; channel, program, and timbre setting modes are set for the same line by using switches 3-2, 3-3, and 3-4, and the alteration of the channel, program, and pitch are performed by using switches 3-5 and 3-6. An operation of the embodiment having the above construction will now be described with reference to the flow charts of Figs. 3A, 3B, and 4. The description will be made first with respect to the processing of the setting and alteration of parameter data (in the edit mode) with reference to Figs. 3A, 3B. In step S1, the edit mode is detected. Then, in step S2, microcomputer 20 effects a check as to whether mode switch 3-1 is "off", i.e., a check as to whether the play mode or edit mode is required. If it is detected that the mode switch is "off", the play mode is detected, in step P1 as shown in Fig. 4. If the mode switch is not "off", the routine goes to step S3 of a check of the state of the system selection switches of group 5, to determine the selected system. In subsequent step S4, a check of the state of the line selection switches of group 4 is performed, to determine the selected line. In subsequent step S5, a check of the state of channel switch 3-2, i.e., a check as to whether channel switch 3-2 is "on", is performed. If the channel switch is not "on", the routine goes to step S6 of a check of the state of timbre program switch 3-3, i.e., a check as to whether the timbre program switch is "off". If the timbre program switch is not "on", the routine goes to step S7 of a check of the state of pitch (note) switch 3-4, i.e., a check as to whether note switch 3-4 is "on". If the pitch (note) switch is not "on", the routine goes back to step S2. If it is detected in step S5 that the channel switch is "on", in step S8 of Fig. 3B, channel data allotted to the system line determined in steps S3 and S4 is read out from RAM 22 and is displayed as prevailing channel data on display section 7. Then, in step S9, a check to determine whether one of switches 3-5 and 3-6 is "on", is performed. If one of these switches is "on", the routine goes to step S10, in which ALU 25 effects alteration of channel data, the new data being written in RAM 22 and displayed on display section 7. Thereafter, the routine returns to step S2. If it is detected, in step S6, that the program switch is "on", steps S11 through S13 are executed. Steps S11 and S12 are, respectively, like steps S8 and S9. A difference is that these steps are executed based not on channel data but on timbre program designation data. In step S13 subsequent to step S12, in addition to the process of writing the new timbre program data in RAM 22 and displaying the data on display section 7, output processing with respect to the analysis is executed so that the performer can confirm aurally the alteration of the parameter data. More specifically, microcomputer 20 prepares new parameter data together with a key-on command and provides these data as tone control signal to tone generator unit 27. In response to this signal, tone generator unit 27 operates the designated channel and executes the designated timbre program, thus producing a tone signal according to the designated pitch data. Thus, the tone of the new designated timbre and pitch is provided through loudspeaker 28. After completion of step S13, the routine goes back to step S2. If it is detected, in step S7, that the note switch is "on", steps S14 through S16 are executed. Steps S14, S15, and S16 correspond to steps S8, S9, and S10. A difference is that these steps are executed based not on channel data but on note or pitch data. Now, the operation in the play mode will be described with reference to Fig. 4. The play mode is detected in step P1. Then in step P2 a check of the state of mode switch 3-1, i.e., a check as to whether the edit mode is required, is performed. If it is detected that the edit mode is required, the edit mode is set in step S1. Otherwise, the play mode is continued, and step P3 is executed, in which input data is analyzed. The flow chart of Fig. 4 is very simplified. Actually, microcomputer 20 commands the time-division basis A/D conversion noted above to A/D converter 14 and fetches input data of the selected line according to the conversion output of A/D converter 14, for level analysis. If it is detected from the result of analysis of input data for a certain line that "a predetermined trigger level is exceeded by the input data" and "detection of the peak of the input data" is effected, the routine goes to step P4, in which microcomputer 20 reads out, from RAM 22, key-on command (which is thought to be generated when the input data level is detected to be above the trigger level), a tone volume level designation code (which is determined from the detected peak of the input data), as well as preset parameter data allotted to the selected line of the used system, i.e., channel designation code, timbre program designation code, and pitch (note) designation code, and produces from these data a tone control signal in a predetermined format suited to, and which is then, fed to tone generator unit 27. Preferably, before providing the key-on command, microcomputer 20 feeds a timbre program designation code for each channel to tone generator unit 27 to be ready for a subsequent percussion operation. Tone generator unit 27 generates a tone signal according to the tone control signal fed from microcomputer 20, and the tone signal is fed to and sounded from loudspeaker 28, with designated timbre and pitch. Until the input data reaches the trigger level, the routine returns to step P2 for the mode check, and the operation described above is repeated for the next line. Although not shown in Fig. 4, if it is detected in the input data analysis process of step P3, that the input level has become lower than a certain level, microcomputer 20 feeds a key-off command to tone generator unit 27 to discontinue the tone. The overall construction and operation of the embodiment have been described so far. Now, the description will be mainly in connection with the operation of envelope extracting circuit 13, A/D converter 14, and microcomputer 20, with reference to Figs. 5 to 7. As described above, the above circuit performs a time-division basis operation to detect the operations of the eight drum pads independently. In the following, an operation that takes place with a percussion operation of a single drum pad 10 will be described for the sake of simplicity of description. In the following description, it is assumed that foot switch 121, which designates one of two different tones (in this example open highhat and closed highhat) to microcomputer 20, is connected to microcomputer 20. It is also assumed that foot switch 121 is operative with respect to a single particular drum pad, e.g., the first drum pad 10. When the first drum pad 10 is struck with foot switch 121 held depressed to be "on", first tone designation data stored in RAM 22 and a key-on command signal are sent out. When the same drum pad 10 is struck with foot switch 121 "off", second tone designation data stored in RAM 22 and a key-on command signal are sent out. More specifically, when the first drum pad 10, i.e., a vibration plate thereof, is struck with a predetermined intensity by drumstick 12, the vibrations caused by the impact are sensed by pick-up 11 mounted on drum pad 10. Pick-up 11 thus produces an analog signal of a waveform, as shown in (A) in Fig. 5. This analog signal is fed to envelope-extracting circuit 13. Envelope-extracting circuit 13 thus produces an envelope signal having a waveform as shown in (B) in Fig. 5. The extracted envelope signal is fed to A/D converter 14 which then converts the input envelope signal into a digital signal at every output timing of the A/D start signal, shown in (C) in Fig. 5, which is provided periodically from timer 21 in microcomputer 20. Immediately after each output timing of the A/D start signal, A/D converter 14 feeds an end signal (shown in (D) in Fig. 5) indicative of the end of A/D conversion operation, to microcomputer 20. The digital signal provided from A/D converter 14 is processed in microcomputer 20, in a routine as shown in the flow chart of Figs. 6A - 6C. More specifically, microcomputer 20 starts the processing in step R-1 of Fig. 6A. In step R-2, process jumps to sub-routine M of Fig. 6C. In step M-1 of sub-routine M, an A/D start signal is fed to A/D converter 14 when a predetermined time interval has been counted by timer 21 in microcomputer 20. In subsequent step M-2, a check is performed as to whether there is an end signal indicative of the end of the conversion into a digital signal performed by A/D converter 14 according to the A/D start signal. If the end signal is detected, a decision "YES" is produced, and the routine goes to step M-3, in which microcomputer 20 fetches data of the digital signal. When the operation of step M-3, i.e., fetching of the digital signal data to microcomputer 20, is completed, the subroutine returns to the main routine, to execute step R-3. In step R-3, a check is performed as to whether the level of the digital signal fetched to microcomputer 20 is above "5". If the decision is "YES", the routine goes to step R-4, in which the fetched data (i.e., level of "5") is stored or saved in RAM 22. If the decision is "NO", the routine goes back to step R-2, to repeat the operation as described. In this embodiment, the digital signal has a level of, for instance, "13" at timing A ○ in (D) in Fig. 5. Since this value is above "5", it is saved in RAM 22. Through the operation of storing this level value of "13" in RAM 22, it is decided that drum pad 10 has been struck at this instant. In subsequent step R-5, the envelope signal at the timing of the next A/D start signal, i.e., timing B ○ in (D) in Fig. 5, is converted into a digital signal through steps M-1 to M-3 of sub-routine M. The digital signal is saved in RAM 22, in step R-6. Then, in step R-7, the envelope signal at the timing of the next A/D start signal (i.e., timing C ○ in (D) in Fig. 5) is converted into a digital signal, which is saved in RAM 22, in step R-8. In subsequent step R-9, the maximum level value among the level values "3" "28", and "40" of digital signal at timings A ○, B ○, and C ○ (i.e., value "40" in this case) is obtained. This maximum level value of "40" is regarded to be the intensity of impact of striking drum pad 10. In subsequent step R-10, a check is performed as to whether foot switch 121 is "on". If the decision is "YES", the first tone designation data in RAM 22 is designated, and in subsequent step R-11, this first tone designation data (i.e., channel code "01" and pitch No. "15") and tone volume designation data corresponding to the maximum level noted above are fed together with a key-on command, for the first channel, (i.e., code "40" in Fig. 7) to tone generator unit 27. According to this key-on command, the closed highhat tone is sounded from the tone generator for the first channel, on the basis of the data noted above. If the decision of the check in step R-10 is "NO", the second tone designation data in RAM 22 is designated. In this case, this second tone designation data (i.e., channel code "02" and pitch No. "20", in Fig. 7) and the tone volume designation data corresponding to the maximum level are fed together with a key-on command (code "40") to the tone generator unit for the second channel. Thus, the open highhat tone is sounded from the tone generator for the second channel, according to the key-on command and the various data noted above. The closed highhat tone or open highhat tone sounded in step R-11 or R-12 is gradually attenuated until the level value of the digital signal from A/D converter 14 becomes "2". More specifically, in step R-13, sub-routine M is executed, and in subsequent step R-14, a check is performed as to whether the level value is less than "2". If the decision is "NO", the routine returns to step R-13. If the level value of the digital signal becomes less than "2" at timing D ○ in (E) in Fig. 5, step R-14 produces a decision "YES", and step R-15 is executed, in which timer 21 in microcomputer 20 is started. In subsequent step R-16, a check is performed as to whether a predetermined time t has passed from timing (D) noted above. If the decision is "YES", the routine goes to step R-17. If the decision is "NO", the routine returns to step R-15. In the case of the decision "YES", a check is performed, in step R-17, as to whether the prevailing tone is sounded with foot switch 21 "on". If the decision is "YES", step R-18 is executed, in which a key-off command (code "00") for discontinuing the closed highhat tone being generated with foot switch 121 "on" is fed to the tone generator unit for the first channel, thus causing quick attenuation of closed highhat tone. If the decision is "NO", step R-19 is executed, in which a key-off command (code "00") for discontinuing open highhat tone being generated with foot switch 121 "off" is fed to the tone generator unit for the second channel, thus causing quick attenuation of the open highhat tone. As has been shown, either first or second tone designation data in RAM 22 in microcomputer 20 is selected by means of a switch-on or switch-off signal fed to the microcomputer, depending on whether foot switch 121 is "on" or "off". Thus, when drum pad 10 is struck, either the closed highhat tone or the open highhat tone can be sounded from the corresponding tone generator unit according to the selected tone designation data. In other words, two different tones can be selectively sounded with a simple construction using a single drum pad 10. Further, the closed highhat tone is generated with foot switch 121 depressed, while the open highhat tone is generated with foot switch 121 released. Thus, even in the case of highhat as a usual natural percussion instrument, like the case of the above embodiment, it is possible to generate closed highhat with the foot switch depressed and generate open highhat with the foot switch released. In other words, it is possible to generate either closed highhat or open highhat tone in the same manner of depression as the highhat (symbal) of the original musical instrument. Further, in the above embodiment, the analog signal from pick-up 11 installed on drum pad 10 is converted via A/D converter 14 into a digital signal before being produced as a musical tone from tone generator unit 27, unlike the prior art case where all the tones are processed analog-wise, it is possible to obtain a variety of tones, utilizing a simple construction. Further, in the above embodiment, because a tone is generated on the basis of the maximum value of the level of digital signal produced from A/D converter 14, it is possible to generate a tone on the basis of the maximum impact of the striking of drum pad 10. It is thus possible to generate tones reliably every time. Further, in the above embodiment, a predetermined time t is counted by timer 21 from the instant when the level value of digital signal from A/D converter 14 becomes less than "2", and attenuation of the tone being sounded is started according to a key-off command generated from microcomputer 20 after the lapse of the time noted above. Thus, even in case when drum pad 10 is struck immediately after the instant when the digital signal level value becomes less than "2" (frequently in case of an erroneous operation, such as a double striking), it is possible to prevent generation of consecutive tones due to the double striking. The tone being sounded thus can be quickly attenuated and discontinued. Further, in the above embodiment, a tone of a volume or a timbre corresponding to the maximum level of the digital signal is generated. However, it is possible to generate a tone with a volume or a timbre corresponding to the level of the digital signal when the level exceeds a predetermined level at the timing of delivery of a certain A/D start signal. Further, in the above embodiment, A/D converter 14 is provided between envelope-extracting circuit 13 and microcomputer 20, and a predetermined tone is generated on the basis of the provision of a digital signal above a predetermined level or at a maximum level, from A/D converter 14. However, it is possible to let the envelope signal from envelope-extracting circuit be fed directly to microcomputer 20, so that a predetermined tone is generated on the basis of the provision of an envelope signal above a predetermined level or at a maximum level from envelope extracting circuit 13. Further, in the above embodiment, two different tones are selectively sounded depending on whether foot switch 121 is "on" or "off". However, it is also possible to cause selective sounding of two different tones depending on the "on" or "off" state of a manual switch instead of foot switch 121. Further, while in the above embodiment two different tones are selectively sounded, it is also possible to let one of three or more different tones be selectively sounded. Further, various other changes and modifications of the above embodiment are possible without departing from the scope of the invention. For example, in response to the operation of one of system switches 5-1 to 5-4 shown in Fig. 2, all corresponding preset data, i.e., preset parameter data for lines L1 to L8, may be provided together with a key-on command to tone generator unit 27, for effecting demonstration through loudspeaker 28. The user can thus confirm aurally the tones allotted to lines L1 to L8, i.e., from respective drum pads 10. Further, instead of or along with this, all preset data (system data) may be displayed cyclically or collectively on display section 7 in accordance with the operation of a particular system key. Further, while in the above embodiment touch sensitive tone volume designation is performed through peak detection based on input data analysis, this processing may be omitted, if desired. Likewise, it is possible to dispense with the key-off command. Further, in the above embodiment, an envelope signal is extracted from the analog voltage signal provided from pick-up 11 and is converted, in A/D converter 14, into a digital signal for the sounding start and end control noted above. It is possible to effect extraction of the envelope signal after conversion of the analog voltage signal from pick-up 11 into a digital signal. In this way, the same effects can be realized with a slight modification of the construction. As has been shown in the foregoing, according to the invention, an envelope signal generated with the actuating of a vibration member is converted into a digital signal, and the start and end of the sounding of a desired tone are controlled according to this digital signal. Thus, it is possible to generate a variety of different performance tones reliably, utilizing a simple construction. Further, according to the invention, setting means are provided to add programmable setting elements to parameter data contained in a tone control signal to be fed to the tone generation unit according to an analog signal from the analog trigger signal generator. Thus, it is possible to freely set and alter pitch data, timbre data, etc. The user thus can freely and easily construct an electronic musical instrument system according to a piece of music, to be performed or matched to his or her taste. Further, a particular one of at least two different tones can be selectively sounded via a selective designation operation of a foot switch or similar designating means. Thus, by actuating a single vibration member, a particular one of at least two different tones can be selectively sounded. This means that tones rich in variation can be sounded, utilizing a simple construction. Further, while the above embodiment of the invention has been applied to percussion instruments, the invention can of course be applied to electronic string musical instruments as well.

Claims: An electronic musical instrument, comprising: [a] analog signal generating means ( 11 ) for generating an analog signal representing vibrations of a vibration member ( 10 ) which is operative for a musical performance; [b] tone generating means ( 27 ) for generating a tone signal corresponding to the vibrations of said vibration member ( 10 ); and [c] control means ( 20 ) for controlling said tone generating means ( 27 ) by designating a characteristic of a desired tone depending on the respective level of said generated analog signal; characterized by [d] envelope extracting means ( 13 ) for extracting an envelope signal from said analog signal; and [e] analog-to-digital conversion means ( 14 ) for converting said envelope signal into a digital signal; [c1] wherein said control means ( 20 ) [c1.1] detects ( R-3 to R-8 ) the levels of said digital signal for a predetermined number of times from the instant ( R-3 ) at which the level of said digital signal exceeds a predetermined value, [c1.2] further detects ( R-9 ) a maximum level from among said detected levels and [c1.3] designates ( R-11 ) a volume level or a timbre of the desired tone according to said detected maximum level. An instrument according to claim 1, characterized in that said control means (20) includes first means for instructing the start of said tone, by detecting that the level of said digital signal from said analog-to-digital conversion means (14) exceeds a predetermined level. An instrument according to claim 1, characterized in that said control means (20) includes second means for instructing the stopping of said tone, by detecting that the level of said digital signal from said analog-to-digital conversion means (14) has become less than a predetermined value. An instrument according to claim 2, characterized in that said first means includes instructing means for detecting the level of said digital signal for a predetermined number of times from the instant when the level of said digital signal from said analog-to-digital conversion means (14) exceeds said predetermined value, detecting a maximum one of said detected levels and instructing the generation of the tone according to the digital signal of said maximum level. An instrument according to claim 1, characterized in that said control means (20) includes: detecting means (20) for detecting the maximum level of said digital signal generated from said analog-to-digital conversion means (14) within said predetermined number of lines; and control means for controlling a characteristic of a tone to be generated from said tone generating means (27,28) according to said maximum level detected by said detecting means (20). An instrument according to claim 3, characterized in that said second means (20) includes delay means for discontinuing the generation of said tone after the lapse of a predetermined period of time from the instant when the level of said digital signal from said analog-to-digital conversion means (14) becomes said predetermined value or a value slightly lower than said predetermined value. An instrument according to one of claims 1 to 6, characterized in that said control means ( 20 ) comprises: a manually-operative means ( 121 ); and instructing means ( 20 ) for instructing selective generation of at least two different tone signals to be generated from said tone generating means ( 27 ) according to the operating state of said manually-operative means ( 121 ). An instrument according to claim 7, characterized in that said manually-operative means ( 121 ) is a foot switch.

Inventors: NAKAMURA KAZUHISA C O PAT DPT, TSUTSUMI KENICHI C O PAT DPT D, UCHIYAMA SHIGERU C O PAT DPT D, NAKAMURA, KAZUHISA C/O PAT. DPT. DEV. DIV., TSUTSUMI, KENICHI C/O PAT. DPT. DEV. DIV., UCHIYAMA, SHIGERU C/O PAT. DPT. DEV. DIV.
Applicants: CASIO COMPUTER CO LTD, CASIO COMPUTER COMPANY LIMITED
Application year: 1986
Main classification: G10H3
IPC codes: G10H3