EP0264955A2 - Gerät zur Bestimmung der Tonhöhe eines im wesentlichen periodischen Eingangssignales - Google Patents

Gerät zur Bestimmung der Tonhöhe eines im wesentlichen periodischen Eingangssignales Download PDF

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Publication number
EP0264955A2
EP0264955A2 EP87115594A EP87115594A EP0264955A2 EP 0264955 A2 EP0264955 A2 EP 0264955A2 EP 87115594 A EP87115594 A EP 87115594A EP 87115594 A EP87115594 A EP 87115594A EP 0264955 A2 EP0264955 A2 EP 0264955A2
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EP
European Patent Office
Prior art keywords
cpu
zero
peak
register
pitch
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Granted
Application number
EP87115594A
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English (en)
French (fr)
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EP0264955A3 (en
EP0264955B1 (de
Inventor
Shigeru Pat. Dept. Dev. Hamura Uchiyama
Katsuhiko Pat. Dept. Dev. Hamura Obata
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Casio Computer Co Ltd
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Casio Computer Co Ltd
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Priority claimed from JP61253487A external-priority patent/JPS63106795A/ja
Priority claimed from JP61282142A external-priority patent/JPS63136088A/ja
Priority claimed from JP61283292A external-priority patent/JP2555551B2/ja
Priority claimed from JP61285985A external-priority patent/JPS63139399A/ja
Priority claimed from JP61286745A external-priority patent/JPS63141099A/ja
Priority claimed from JP62004714A external-priority patent/JP2508044B2/ja
Priority claimed from JP62050381A external-priority patent/JPH07104666B2/ja
Priority to EP92105224A priority Critical patent/EP0493374B1/de
Application filed by Casio Computer Co Ltd filed Critical Casio Computer Co Ltd
Publication of EP0264955A2 publication Critical patent/EP0264955A2/de
Publication of EP0264955A3 publication Critical patent/EP0264955A3/en
Publication of EP0264955B1 publication Critical patent/EP0264955B1/de
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H3/00—Instruments in which the tones are generated by electromechanical means
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H2210/00—Aspects or methods of musical processing having intrinsic musical character, i.e. involving musical theory or musical parameters or relying on musical knowledge, as applied in electrophonic musical tools or instruments
    • G10H2210/031—Musical analysis, i.e. isolation, extraction or identification of musical elements or musical parameters from a raw acoustic signal or from an encoded audio signal
    • G10H2210/066—Musical analysis, i.e. isolation, extraction or identification of musical elements or musical parameters from a raw acoustic signal or from an encoded audio signal for pitch analysis as part of wider processing for musical purposes, e.g. transcription, musical performance evaluation; Pitch recognition, e.g. in polyphonic sounds; Estimation or use of missing fundamental

Definitions

  • the zero-cross point detection system detects the time intervals between zero-cross points in the input waveform, and uses them as periods of the artificial sound.
  • the input waveform frequently contains harmonics which should have been removed by filters such as low-­pass filters.
  • the detection system does not operate well for such input waveforms. If it is applied, the detected pitches contain many errors. To prevent the errors, complicated software processings, for example, to check the duty of the input waveform, are required. It is technically difficult to realize this.
  • KOKAI 55-159495 and KOKOKU 61-51793 disclose a frequency stabilizing technique in which when the adjacent extracted periods are substantially the same, the sounding of the musical instrument starts. A sounding command is not sent to the sound source until at least two periods elapse. In this respect, these patent applications involve the response performance problem. To obtain a quick response, the sounding should start as soon as possible.
  • FIG. 3 A specific configuration of minimum peak detector 5 is shown in Fig. 3.
  • the circuit configuration of this circuit 5 is substantially the same as that of the maximum peak detector 4 as mentioned above, except for the connection of diode D2 being opposite. Accordingly, capacitor C repeats the charge/discharge in the opposite directions as shown in Fig. 4d. Finally, the interrupt command signal INTb as shown in Fig. 4e is obtained.
  • the frequency control processing is a musical tone sounding processing in which the data from counter 7 is directly applied to frequency ROM 8 or the pitch code as indicated by the fret number extracted on the basis of that data is applied to frequency ROM 8. So long as the musical tone level is above the predeter­mined level, CPU 6 continues this sounding processing (steps A2, A3 and A5). The count data of counter 7 is set through the interrupt processing as given later.
  • the corresponding frequency data is output from frequency ROM 8 in step A5.
  • the frequency is changed two times (MAX1-MAX1 and MIN-MIN) during one period. This implies that the system of the musical instrument can quickly respond to the frequency variation of the input signal.
  • a second embodiment of the present invention will be described.
  • a new pitch extraction system will be discussed in the second embodiment.
  • the maximum and/or minimum peaks of the waveform of a musical tone i.e., an input signal
  • the maximum and/or minimum peaks of the waveform of a musical tone i.e., an input signal
  • zero-cross points immediately after the maximum or minimum peaks are detected.
  • a time interval between the detected zero-cross points is obtained.
  • the pitch of the input signal wave­form is obtained using the time interval.
  • Each maximum peak detectors 4 detects the maximum peak point of an input signal waveform.
  • flip-flop (FF) 214 located at the post stage of each detector 4 outputs the Q out­put at high level.
  • the output signal of FF 214 and the inverted output of inverter 230 coupled with zero-cross point detector 206 are applied to AND gate 224.
  • the output signal from AND gate 224 is applied as interrupt signal INTan (where n is any of 1 to 6 figures) to CPU 200.
  • each minimum peak detectors 5 detects the minimum peak point of an input signal waveform.
  • flip-flop (FF) 215 located at the post stage of each detector 5 outputs the Q output at high level.
  • the output signal of FF 215 and the inverted output of inverter 230 coupled with zero-cross point detector 206 are applied to AND gate 225.
  • the output signal from AND gate 225 is applied as interrupt signal INTbn (where n is any of 1 to 6 figures) to CPU 200.
  • CPU 200 Immediately after receiving the interrupt signal INTan or INTbn, CPU 200 applies clear signal CLan (where n is any of 1 to 6) or CLbn to FF214 or 215. In turn, the corresponding FF is reset. Accordingly, until the next maximum or minimum peak point is detected, even if the waveform crosses the zero level any number of times, the corresponding FF remains reset, and therefore CPU 200 is never interrupted.
  • step B5 When the zero-cross point (Zero 5) succeeding to the maximum peak point MAX2 shown in Fig. 13(a) is reached, interrupt signal INTa for the detection of the zero-cross point following the maximum peak point is generated, and CPU 200 fetches the count of counter 7 in step B10. In step B2, if the CPU confirms that the present wave is not the first wave. Then, in step B3, the CPU checks if the flag is "0".
  • step B301 This routine is similar to those of Figs. 7 and 13.
  • CPU 200 resets FF 214 in step B301, reads in the count of counter 7, and in step B302 checks if the rise flag is 1. Since the waveform has just risen, and the pres­ent wave of the waveform is the first wave, the CPU advances to step B303 (see steps A16 (A26, A36, A46, A56, A66), and in this step executes the processing of starting the sounding at the note by the open string.
  • step B304 the rise flag is cleared, and the CPU pro­ceeds to step B305 where it sets the control flag to "1". Then, the CPU saves into in-maximum memory 201 the counter 7 count as read out in step 301.
  • the control flag "1" indicates that the zero-cross point after the maximum peak point has been detected.
  • the cleared flag indicates the detection of the minimum peak point. The function of this control flag will be discussed later.
  • step B304 (Fig. 19)
  • the rise flag has been cleared.
  • the result of the check in step 302 is NO.
  • the judgement in step C307 can be attained by pro­viding such a flag in CPU 200 that is turned on during the period of time from the generation of the musical tone of the open string to the arrival of the next interrupt signal INT, and is turned off in other periods of time.
  • the arrival time of the next interrupt signal INT is more exactly the time when the next interrupt signal INTan (where n is any of "1" to 6) arrives when the input waveform rises, and the time when the next interrupt signal INTbn (n is any of 1 to 6) arrives when the input waveform falls. In the example shown in Fig. 9, it is the timing of zero-cross point Zero 5.
  • the musical tone at the note of this string when it is in the open string, is generated at the generation of the first interrupt signal INTa for waveform rise or INTb for waveform fall.
  • the next interrupt signal which is of the same type
  • two types of time intervals are obtained, and the frequency change is performed two times during one period.
  • One of the two types of the intervals is the time interval (t1) between the zero-­cross points, i.e., Zero 1 and Zero 5, immediately after the maximum peak values are detected.
  • the other is the time interval (t2) between the zero-cross points, i.e., Zero 4 to Zero 8, generated immediately after the mini­mum peak values are detected. Therefore, the musical tone can quickly be output in response to the generation of the input signal.
  • the pitch is extracted, the operation of the electronic guitar follows up a frequency change of the input signal by setting the sounding note based on the extracted pitch.
  • the frequency change is made until the first one wave of the note sound of the open string is completed, as shown in Fig. 18(g). Therefore, the actual tone frequency can be obtained before the player feels the periodicity (i.e., the fre­quency or pitch) of the output sound at the early stage of sounding.
  • the sounding start is possible at early timing, and the player hear the sound with natural feeling of sound at the time of sounding start.
  • CPU 200 detects the string vibration before the maximum peak value MAX1 in Fig. 18(a), that is, CPU 200 detects that A/D converter 11 outputs a signal at an amplitude larger than a prede­termined level
  • the CPU applies a sounding start command of the open string note to frequency ROM 8 and sound source circuit 9 in the processing to set the rise flag to "1" (steps A13 and A16, A23 and A26, A33 and A36, A43 and A46, A53 and A56, A63 and A66).
  • the fourth embodiment is based on the fact that three items of distinctive period information exist between two periods of the input signal waveform. Within the time interval of less than two periods of the input signal waveform, two periods of the waveform are detected. If the detected two periods are almost equal to each other a controller issues a command to start the sounding.
  • the above technical features reduces the time from the arrival of the input signal to the generation of artificial acoustic wave, providing attractive perfor­mance by the guitar.
  • Fig. 21 shows a main routine executed by CPU 400.
  • This routine is similar to those of early mentioned embodiments.
  • the main routine illustrated is for pro­cessing the musical tone generated by one string of the guitar. This processing is correspondingly applied for other five strings.
  • CPU 400 executes these routines in a time divisional manner.
  • CPU 400 first executes step A401 to initialize the system of the electronic guitar. Following this, CPU 400 reads on the contents of A/D converter 411 in step A402.
  • the CPU continues the tone-off processing of musical tone until the output level of A/D converter 41 reaches a predeter­mined level (steps A403, 404, and 405). If the guitar string is picked, and the musical tone signal above the predetermined level as shown in Fig.
  • step A406 If the answer to the step A406 is NO, that is, when interval tl between zero-cross points Zero 1 and Zero 5 is not equal to the interval t2 between zero-cross points Zero 4 and Zero 8, no sounding starts and the CPU waits for the next interrupt processing. Then, the CPU checks if the time interval t2 between the points Zero 4 and Zero 8 is equal to the next time interval t1 ranging from zero-cross points Zero 5 to Zero 9 (Fig. 23(a)). This is made in step A406. If the check result is YES, the CPU advances to step A407 where it directs the start of sounding.
  • detectors 4 and 5 may be the same as those of the first embodiment.
  • step B502 the CPU clears FF 214, and executes the step B503 to fetch the count of counter.
  • the CPU detects the value of t1, i.e., the interval between the zero-cross points respecting following the maximum peak points of the waveform. This is obtained as the dif­ference between the count of counter 7 and the value of in-maximum memory 201.
  • step A505 CPU 400 issues a command to sound the musical tone at the frequency based on time interval t1.
  • step B505 gives the answer of NO at timing (1) of Fig. 9(b). Then step B508 is executed.
  • step B505 is used for checking if "an” exceeds "a”. This step is not essen­tial. In this case, the CPU jumps from step B504 to step B506, and in this step, the CPU checks whether or not the input waveform level exceeds a predetermined level by using the relation of (an - an-1) R.
  • the present invention is applied for the electronic guitar, it can be applied for any other systems of the type in which pitches are extracted from a sound signal or an electrical vibration as input from a microphone, for example, and an acoustic signal, which is different from the original signal, is generated at the pitches or note frequencies corresponding to those of the original signal.
  • pitches are extracted from a sound signal or an electrical vibration as input from a microphone, for example, and an acoustic signal, which is different from the original signal, is generated at the pitches or note frequencies corresponding to those of the original signal.
  • Specific examples of such are electronic pianos with key boards, electronic wind instruments, electronic string instruments such as electronic violins and koto (Japanese string instrument).
  • the period measurement starts when both the positive and negative peak points appear as shown in Fig. 32(c).
  • the period of (c) is not measured, but the period of (d) is measured. This indicates that the sounding start timing is slightly delayed.
  • a STEP register contains four stages 0, 1, 2, and 3.
  • the contents of the STEP register progressively change, as shown in Fig. 36(b) or Fig. 37(b), as the string is picked and vibrates (Fig. 36(a) or Fig. 37(a)).
  • the contents 0 of this register represents the note-off state.
  • a REVERCE register stores the data to check whether the interrupt processing has been made, which is exe­cuted at the arrival of the zero-cross point after the peak point which is located in opposition to the zero-­cross point as given by the SIGN register.
  • An AMP (i) register stores the maximum or minimum peak value, more exactly, its absolute value, which is applied from A/D converter 11 and latched in latch 12.
  • An AMP (1) register stores the maximum peak value, and an AMP (2) is for minimum peak value storage.
  • step Q8 the CPU sets "1" to the STEP register.
  • step Q9 the CPU sets "0" to the REVERSE register.
  • step Q10 the CPU inputs the value of a ⁇ into the SIGN register. The value of a ⁇ is "1" at the zero-cross point immediately after the maximum peak point, and is "2" at the zero-cross point immediately after the minimum peak point.
  • the CPU ad­vances from step Q4 to step Q22 in the main routine processing, and checks if the value of the present peak point b ⁇ is above OFFLEV as shown in Fig. 38.
  • the CPU advances to step Q23, and judge whether or not the relative-on processing should be executed.
  • the CPU checks if the value of the present peak point (b ⁇ ) is above that of the previous peak point by ONLEVII, i.e. checks if the value of the extracted peak point rapidly increases during sounding.
  • this embodiment discretely picks up a variation of the frequency of string vibration, and controls the frequency according to the picked up discrete data in a real time manner.
  • the waveform contain much intensive harmonics has many peak points and cross points. If the electronic guitar receives such a waveform, it mistakenly measure one wave length time interval P as intervals PS and PR, which are each dif­ferent from the true time interval P. The guitar sounds the musical tone at incorrect pitches. This is problematic in the technique disclosed in KOKOKU No. 61-51793. In this technique, when the adjacent waveform periods are substantially equal, the frequency control is executed on the basis of the time length of the period compared.
  • a control directs the sounding of a musical tone at the frequency as defined by the time length.
  • An arrangement of the seventh embodiment is substantially the same as that of the sixth embodiment (Fig. 33).
  • the interrupt routines INTa and INTb exe­cuted by CPU 600 are the same as those in the sixth embodiment.
  • step S1 gives YES
  • step S2 is executed to read out the contents a ⁇ , b ⁇ and t ⁇ .
  • step S3 CPU 600 reads out the value of peak point of the same type (maximum or minimum from AMP(a ⁇ ) register, and loads it into the s ⁇ register in the CPU. Further, the CPU sets the peak value b ⁇ now extracted in the AMP(a ⁇ ) register.
  • step S4 the CPU if the contents of TRIGGER register is "1" or not. If the system of the electronic guitar is in the initial condition "1" cannot be set in the register, the CPU goes to step S5 where it checks if the note-on condition has been set up or not. In this case, however, the note-on condition has not been set up, and the CPU returns to step S1. If the input signal whose level is larger than ONLEVI comes in, step S6 gives the answer of YES and then step S7 will be exe­cuted.
  • step S16 When the string is picked, the string gradually damps toward zero.
  • the answer of this step S16 is NO.
  • the answer of step S16 may be YES, although this is a rare case.
  • step S16 gives YES and flow jumps to step S17 and steps S8 and S9 are exe­cuted consecutively.
  • "1" is set in the TRIGGER register and exactly the same operation as that at the sounding start will be executed. In other words, steps S12 to S14 are successively executed to effect the relative-on processing.
  • step S17 following step S16 is executed to compare the value of a ⁇ and the value of the SIGN register. If these are not coincident as in the case of zero-cross points Zero 4, Zero 6, ..., steps S18 and S19 are executed. In these steps the contents of the TR register is subtracted from the t ⁇ register to obtain the second period PR.
  • the PR is set in the PR register, and the value of t ⁇ is set in the TS register in order to obtain the pitch data of the next period PR.
  • step S20 is executed.
  • step S the contents difference between the t ⁇ -register and TS register is obtained to have the pitch data of the next third period.
  • the difference is set in the P register.
  • the value t ⁇ is set in the TS register in order to obtain the pitch data of the next third period P, in step S21.
  • the electronic guitar discretely picks up the fre­quency variation in the string vibration time to time, and executes the frequency control on the basis of the picked up data in a real time manner.
  • the present invention is applied for the electronic guitar, it can be applied for any other systems of the type in which pitches are extracted from a sound signal or an electrical vibration as input from a microphone, for example, and an acoustic signal, which is different from the original signal, is generated at the pitches or note frequencies corresponding to those of the original signal.
  • pitches are extracted from a sound signal or an electrical vibration as input from a microphone, for example, and an acoustic signal, which is different from the original signal, is generated at the pitches or note frequencies corresponding to those of the original signal.
  • Specific examples of such are electronic pianos with key boards, electronic wind instrument electronic string instruments such as electronic violins and koto (Japanese string instrument).
  • the seventh embodiment measurement is made of the time length of a first wave of an input waveform which par­tially overlaps one wave of the same waveform, and the time length of a second wave also overlapping the first wave. If the measured time lengths are substantially equal, the CPU directs the sounding of a musical tone at the frequency as defined by the time length.
  • the system of the electronic guitar which is best on the three periods comparison, can exactly extract the pitch of the waveform even if it contains much harmonics.
  • Control goes to step C806, and further to step C807 to write the value of b1 into a predetermined memory area of the peak memory.
  • step C801 2 is obtained and control flows to step C809.
  • step B812 when the tremolo playing is made, and before the sounding terminates, a string is picked again, the interrupt processing is executed when the zero-cross point following the maximum peak of an-1 is reached, in step B812, the answer of YES is given since an+1 - an > R, and control flows step B814.
  • the CPU gives the note-off command to sound source circuit 9 and abruptly drops the sounding level (Fig. 43(h)).
  • any other suitable detection may be used for detecting the rapid increase of the waveform during the sounding.
  • the ninth embodiment is based on the scheme that the note-off is executed if the maximum and minimum peak values of the input wave­form are below those previous peaks, respectively.
  • step S904 the CPU judges whether or not the contents of a ⁇ -, b ⁇ - and t ⁇ -register are saved into work memory 601 through the interrupt processing in step S904.
  • Primed characters a ⁇ , b ⁇ and t ⁇ correspond to a, b and c above, and indicate that these items of data have previously stored, respectively. If no interrupt processing has been executed, the answer to step S904 is NO, and the CPU repeats the execution of step S904.
  • sequences of steps S904 to S908, and S919 to S923 are executed and YES is given in step S23.
  • a sequence of steps 924 to 926 is executed to set a new period ranging from Zero 3 to Zero 5 into the PERIOD register and transfers the contents of the t ⁇ -register into the T register.
  • new period measurement starts.
  • the CPU issues a frequency change command to frequency ROM 8 and sound source circuit 9, according to the pitch this time detected and stored in the PERIOD register.
  • CPU 600 executes the sequence of steps S904 to S908, and S919 to S921, and in steps S927 and 928 the CPU checks if "1" is set in the FLAG (i) for the opposite peak point. At present the register contains “1” and therefore the CPU clears the FLAG (i) register on the opposite side, and sets "3" in the STEP register. In step 932, the CPU executes the note-off processing, and gives to sound source circuit a command to stop the sounding of the musical tone from sound source circuit 9.
  • Fig. 50 Technical problems to which this embodiment is directed is illustrated in Fig. 50.
  • (j) indicates an input waveform
  • (k) an envelope connecting positive peaks
  • (1) a waveform of a positive peak detect signal
  • (m) an envelope connecting negative peaks
  • (n) a waveform of a negative peak detection signal.
  • the output signal from each latch 412 is applied to CPU 1000. This data is used for controlling the controls such as note-on, note-off, pitch extraction start, pitch extraction stop, and control of sounding level (volume control).
  • the peak values as latched in each latch 412 before the output of latch command signals L1 to L6 are stopped, are successively stored into work memory 601.
  • FIG. 29 A main routine of CPU 1000 is illustrated in Fig. 29.
  • An AMP (i) register stores the maximum or minimum peak value, more exactly, its absolute value, which is applied from A/D converter 411 and latched in 412.
  • An AMP (1) register stores the maximum peak value, and an AMP (2) is for minimum peak value storage.
  • An OFF register contains "1" when the level data of the input waveform latched in latch 412 is below OFFLEV as the note-off level shown in Fig. 54. It contains "0” when it is above OFFLEV during the sounding.
  • An OFT register stores the count of counter 7 when 21 ⁇ is set in the OF register. If the time duration of the state of "1" in the OF register is a predetermined time duration, for example, the period of of a string vibration in the open string mode, more exactly, 12 msec for the sixth string, for example, the note-off pro­cessing is executed.
  • ONLEVII is used in such a way that in the note-on mode, when the difference between the previous and this-time detection levels is above the level of ONLEVEII, the CPU executes the relative-on processing even if the tremolo, for example, is used.
  • step S1002 the CPU reads out the registered contents a ⁇ , b ⁇ and t′. Then, the CPU goes to step S1002, and reads out the peak value at the peak point of the same type (maximum or minimum) which has been stored in AMP (a ⁇ ) register. The CPU sets the peak value b ⁇ extracted this time into AMP (a ⁇ ) register.
  • step S1011 the value of t ⁇ -register is set in the T register.
  • the contents of a ⁇ -­register is set in the SIGN register (now SING is "1" in the case of Figs. 36(a) and Fig. 37(a))
  • the contents of the b ⁇ -register is set in the AMP register.
  • the con­tents of the t ⁇ -register is loaded into the T register. Then, the CPU returns to step S1.
  • step S1012 NO is given, and then, the CPU advances to step S1013, and sets "2" in the STEP register (see Fig. 36(b)).
  • step S1017 the CPU has the answer of YES in step S1016, and advances to step S1017 to check if the REVERSE register contains "1". If the value of the REVERSE register is "1", the CPU has the answer of NO, and returns to step S1001. As mentioned above, after execution of step S1015, the value of this register is "1". Then, the CPU advances to step S1018, and inputs "3" in the STEP register (see Fig. 37(b)). In step S1019, the CPU subtracts the value of the T register, i.e., the time of the zero-cross point Zero 1, from the value of the counter 7 given by the this-time interrupt processing, and the CPU loads it in the PERIOD register.
  • T register i.e., the time of the zero-cross point Zero 1
  • step S1021 CPU 1000 issues a sounding start (note-on) command to frequency ROM 8 and sound source circuit 9 in accordance with the contents of the PERIOD register. At this time, the sounding starts.
  • Fig. 36 the main flow after the next zero-cross point Zero 4 is executed again, and the CPU jumps from step S1005 to S1016. Since the value of the SIGN register is now 2, YES is given in step S1016. Subsequently, the sounding start processing in steps S1017 to S1021 are executed. At this time, CPU 1000 recognizes the time interval from zero-cross points Zero 2 to Zero 4 shown in Fig. 36(c), as one period. The guitar starts the sounding of the musical tone at the frequency as defined by the time length recognized (see Fig. 36(d)).
  • the CPU advances from step S1004 to step S1023 in the main routine processing, and judges whether or not the relative-on processing should be executed. In other words, the CPU checks if the value of the present peak point (b ⁇ ) is above that of the previous peak point by ONLEVII, i.e. checks if the value of the extracted peak point rapidly increases during sounding.
  • step S1023 When a string is picked, the vibration of the string gradually damps toward zero. NO is given in step S1023. In case that before the vibration of the string previously picked damps to zero, another string is picked by the tremolo playing, for example, the answer to step S1023 is often YES.
  • step S1027 the contents of the t ⁇ -register are transferred to the T register. Subsequently, on the basis of the value of the PERIOD register obtained in step S1028, CPU 1000 executes the frequency (pitch) control for frequency ROM 8 and sound source circuit 9.
  • the CPU advances from step S1028 to step S1029, and clears the REVERSE register, and finally executes the period measuring.
  • step S1035 recognizes this by using the dif­ference between the count as set in the OFT register and the present count of counter 7.
  • step S1036 CPU 1000 clears the STEP register and the OF register, and executes the note-off processing in step S1037, and gives a note-off command to sound source circuit 9, to stop the sounding.
  • the note-off processing can be executed quickly and reliably, even if the waveform level abruptly changes, by detecting that the waveform level below OFFLEV for 12 msec, for example.
  • harmonics are contained in the natural waveform.
  • the harmonics possibly cause errone­ous frequency change control, when these are detected.
  • the first constants is ONLEVI.
  • step Q119 When a string is picked, the vibration of the string gradually damps toward zero. NO is given in step Q119. In the case where, before the vibration of the string previously picked damps to zero, another string is picked by the tremolo playing, for example, the answer to step Q1119 may be YES.
  • step Q1118 if the input peak value is below OFFLEV, step Q1118 gives NO, and in step Q1126, the STEP register is cleared. The note-on processing is executed in step Q1127. As described, the musical tone thus sounded from sound source circuit is stopped.
  • step Q1130 NO is given, and the CPU returns to step Q1103. Hence, steps Q1103 to Q1108 and Q1129 and Q1130 are executed whenever the zero-cross point is reached.
  • the STEP register is instantaneously set to "0".
  • 3 is set to the STEP register.
  • the CPU waits till the input signal level becomes satisfactorily small, and "0" is set to the register.
  • the string vibration often continues when the harmonic is input. It is possible to prevent the guitar system from being trig­gered for the relative-on by the waveform with the level above ONLEVI.
  • CPU 1200 issues a note-on command to sound source circuit 9.
  • a sound source circuit progressively controls the frequency of a sounding musical tone according to the time interval data, which are successively obtained.
  • timer 1208 counts a predetermined time duration or the time duration required for one command execution. More specifically, timer 1208 receives a control signal from CPU 1200, and measures the predetermined time, and then applies an interrupt signal INTc to CPU 1200.
  • the CPU executes the interrupt processing. This will be described in detail.
  • sound source circuit 9 generates a musical tone at the frequency as defined by the pitch change command. Sound system sounds the musical tone.
  • a STEP register contains four contents 0, 1, 2, and 3.
  • the contents of the STEP register progressively change, as shown in Fig. 36(b) or Fig. 37(b), as the string is picked and vibrates (Fig. 36(a) or Fig. 37(a)).
  • the contents 0 of this register represents the note-off state.
  • a REVERSE register stores the data to check whether the interrupt processing has been made, which is exe­cuted at the arrival of the zero-cross point after the peak point which is located in opposition to the zero-­cross point as given by the SIGN register.
  • a T register stores the count of counter 7 at a specific point to measure the period of the input wave­form. Count 7 free runs responsive to a given clock signal.
  • a PERIOD register stores the data of measured periods. On the basis of the contents of this register, CPU 1200 executes the frequency control for frequency ROM 8 and sound source circuit 9.
  • P and P ⁇ registers store the frequency data repre­senting the extracted pitches (including the frequencies of semitone or less expressed in cent, for example).
  • the first constant is ONLEVI.
  • the system is in the note-off mode. In this mode, when a peak level higher than ONLEVI is detected, the CPU decides that a string has been picked, and starts the period measurement.
  • step 1204 to Q1206 the CPU checks if the contents of STEP register is 3, 2 or 1. When the system of the electronic guitar under discussion is in the ini­tial condition, the STEP register is 0, and therefore the answer to steps 1204, Q1205 and Q1206 is NO. In step Q1207, the CPU checks if the peak value b ⁇ detected this time is above or below the level of ONLEVI.
  • step Q1207 gives the answer of YES and the CPU advances to step Q1208.
  • step Q1208 the CPU sets "1" to the STEP register.
  • step Q1209 the CPU sets "0" to the REVERSE register.
  • step Q1211 the value of t ⁇ is set in the T register.
  • the value of a ⁇ is set in the SIGN register, that of b ⁇ in the AMP register, and that of t ⁇ in the T register.
  • the value of the SIGN register is "1" (Fig. 36(a) and Fig. 37(a)). Then, the CPU returns to step Q1201 again.
  • step Q1212 NO is given, and after that, the CPU advances to Q1213 and sets 2 in the STEP register (see Fig.36(b) and Fig. 37(b)).
  • step Q1214 the CPU executes step Q1214 and compares the previous peak point (AMP (SIGN)) with the present peak point (b ⁇ ). If the previous value X0 is smaller than the present value (X1>X0) as shown in Fig.36(a), YES will be given.
  • the CPU jumps from step Q1214 to steps Q1210 and Q1211, to set 2 in the SIGN register and at the same time to transfer the contents of the t ⁇ -register to the T register.
  • step Q1214 NO is given in step Q1214 and 1 is set in the REVERSE register in step Q1215.
  • the previous value 1 is maintained in the SIGN register.
  • the previous zero-cross point Zero 1 is the period measuring start point, in this case (see Fig. 37(c)).
  • the time length PERIOD shown in Fig. 37(c) is that of one period.
  • the CPU transfers the contents of t ⁇ -register to the T register, and starts the new period measurement.
  • step Q1240 the CPU computes the pitch of the musical tone to be generated on the basis of the PERIOD register, and loads the pitch data (some other data representing the computed data) into the P ⁇ register.
  • the pitch data preferably contains octave, note, and the pitch of semitone or less, which are expressed in the unit of cent.
  • step S1221 CPU 1200 issues a note-on command to sound source cir­cuit 9 in response to the contents of the P ⁇ register. From this time point, the musical tone is generated.
  • the CPU flows to step Q1241.
  • timer 8 starts its count and counts a predetermined time under control of the CPU.
  • step Q1242 "1" is set in the FLAG register.
  • the period measurement is executed from the next zero-cross point after the peak point whose value is larger.
  • the period measurement is completed at the next zero-cross point located in the same side as the previous peak point.
  • one period of low-pass filter 3 output waveform is extracted.
  • step Q23 When a string is picked, the vibration of the string gradually damps toward zero. NO is given in step Q23. In case that before the vibration of the string previously picked damps to zero, another string is picked by the tremolo playing, for example, the answer to step Q23 is often YES.
  • the CPU jumps to step Q1208 after judging YES in Q23, and then executes step Q1209 to step Q1211.
  • the CPU sets "1" in the STEP register, and subsequently executes the same processing as that of the sounding start.
  • the CPU executes step Q1216 to step Q1221 again, and executes the relative-on processing.
  • step Q1228 CPU 1200 transfers the contents of the P register to the P ⁇ register, and in steps Q1241 and 1242, is ready for the next pitch change.
  • CPU 1200 executes the corresponding pro­cessing, and gives a necessary command to sound source circuit 9. In this respect, the guitar system is good in response.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Electrophonic Musical Instruments (AREA)
EP19870115594 1986-10-24 1987-10-23 Gerät zur Bestimmung der Tonhöhe eines im wesentlichen periodischen Eingangssignales Expired - Lifetime EP0264955B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP92105224A EP0493374B1 (de) 1986-10-24 1987-10-23 Gerät zum Erzeugen eines Musiktonsignales gemäss eines Eingangswellenform-Signals

Applications Claiming Priority (14)

Application Number Priority Date Filing Date Title
JP61253487A JPS63106795A (ja) 1986-10-24 1986-10-24 電子楽器の入力制御装置
JP253487/86 1986-10-24
JP282142/86 1986-11-28
JP61283292A JP2555551B2 (ja) 1986-11-28 1986-11-28 入力波形信号制御装置
JP283292/86 1986-11-28
JP61282142A JPS63136088A (ja) 1986-11-28 1986-11-28 電子楽器の入力制御装置
JP61285985A JPS63139399A (ja) 1986-12-02 1986-12-02 波形信号入力制御装置
JP285985/86 1986-12-02
JP61286745A JPS63141099A (ja) 1986-12-03 1986-12-03 電子楽器の入力制御装置
JP286745/86 1986-12-03
JP62004714A JP2508044B2 (ja) 1987-01-12 1987-01-12 電子楽器の入力制御装置
JP4714/87 1987-01-12
JP62050381A JPH07104666B2 (ja) 1987-03-06 1987-03-06 ピッチ抽出装置
JP50381/87 1987-03-06

Related Child Applications (2)

Application Number Title Priority Date Filing Date
EP92105224A Division EP0493374B1 (de) 1986-10-24 1987-10-23 Gerät zum Erzeugen eines Musiktonsignales gemäss eines Eingangswellenform-Signals
EP92105224.7 Division-Into 1992-03-26

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EP0264955A2 true EP0264955A2 (de) 1988-04-27
EP0264955A3 EP0264955A3 (en) 1989-08-30
EP0264955B1 EP0264955B1 (de) 1993-03-17

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EP92105224A Expired - Lifetime EP0493374B1 (de) 1986-10-24 1987-10-23 Gerät zum Erzeugen eines Musiktonsignales gemäss eines Eingangswellenform-Signals
EP19870115594 Expired - Lifetime EP0264955B1 (de) 1986-10-24 1987-10-23 Gerät zur Bestimmung der Tonhöhe eines im wesentlichen periodischen Eingangssignales

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HK (1) HK1005348A1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0318675A1 (de) * 1987-10-08 1989-06-07 Casio Computer Company Limited Vorrichtung zum Ziehen der Tonhöhe aus einem Wellenformsignal
CN108333506A (zh) * 2018-04-08 2018-07-27 杭州欣美成套电器制造有限公司 一种近零信号提取与交流开关位置检测电路
CN111030412A (zh) * 2019-12-04 2020-04-17 瑞声科技(新加坡)有限公司 一种振动波形的设计方法及振动马达

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2138988A (en) * 1983-02-27 1984-10-31 Casio Computer Co Ltd Electronic musical instrument
US4627323A (en) * 1984-08-13 1986-12-09 New England Digital Corporation Pitch extractor apparatus and the like

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6145298A (ja) * 1984-08-09 1986-03-05 カシオ計算機株式会社 電子楽器

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2138988A (en) * 1983-02-27 1984-10-31 Casio Computer Co Ltd Electronic musical instrument
US4627323A (en) * 1984-08-13 1986-12-09 New England Digital Corporation Pitch extractor apparatus and the like

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0318675A1 (de) * 1987-10-08 1989-06-07 Casio Computer Company Limited Vorrichtung zum Ziehen der Tonhöhe aus einem Wellenformsignal
US5018427A (en) * 1987-10-08 1991-05-28 Casio Computer Co., Ltd. Input apparatus of electronic system for extracting pitch data from compressed input waveform signal
CN108333506A (zh) * 2018-04-08 2018-07-27 杭州欣美成套电器制造有限公司 一种近零信号提取与交流开关位置检测电路
CN111030412A (zh) * 2019-12-04 2020-04-17 瑞声科技(新加坡)有限公司 一种振动波形的设计方法及振动马达

Also Published As

Publication number Publication date
DE3784830D1 (de) 1993-04-22
HK1005348A1 (en) 1998-12-31
DE3752185D1 (de) 1998-06-04
EP0493374A2 (de) 1992-07-01
DE3784830T2 (de) 1993-10-14
EP0493374B1 (de) 1998-04-29
DE3752185T2 (de) 1998-08-27
EP0264955A3 (en) 1989-08-30
EP0493374A3 (en) 1992-11-19
EP0264955B1 (de) 1993-03-17

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