Submultiple-related-frequency wave generator4333374Abstract A digital oscillator generates a basic pulse having a period which is a predetermined large number of times of a clock pulse period. During the basic pulse period are allotted a predetermined small number of time slots defining submultiple frequency channels. There is provided a shift register having the channel number of stages, each stage being assigned to each channel. The contents of the respective stages are changed at respectively different periods which are multiples of the basic pulse period. The contents are taken out timewise-serially, one at a time, stage by stage, and superimposed on the basic pulse to constitute a time-division-multiplexed wave data signal. The delivered signal is demultiplexed to form individual waves having respectively different frequencies which are submultiple-related to the frequency of the basic pulse. This generator is very suitable for electronic musical instruments, as a single line transmits plural wave data. Claims What is claimed is: Description BACKGROUND OF THE INVENTION
TABLE 1
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Q.sub.2
Q.sub.1 B.sub.4 B.sub.3
B.sub.2
B.sub.1
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0 0 0 0 0 0
0 1 1 0 1 0
1 0 1 0 0 0
1 1 1 1 1 0
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The output of the switch 42 is applied through a delay flip-flop 45 to the control line 27, thereby to control the frequency division factor of the digital oscillator section 14, that is, the generation interval of the basic pulse P. In the case where the frequency division factor set by the AND circuit 21 is N as described before, when the signal on the control line 27 is raised to "1", the basic pulse signal P is produced at the frequency division factor of (N+1); and when the signal on the line 27 is switched to "0", it is produced at the frequency division factor of N. Accordingly, with respect to the frequency division factor for generating the basic pulse signal P in the digital oscillator section 14, the modulo-N operation is effected at all times when the armature of the switch 42 is connected to the terminal B.sub.1 ; the modulo-N and the modulo-(N+1) operations are repeated when the armature of the switch 42 is connected to the terminal B.sub.2 ; after the modulo-N operation has been effected three times, the modulo-(N+1) operation is effected only once when the armature of the switch 42 is connected to the terminal B.sub.3 ; and when the armature of the switch 42 is connected to the terminal B.sub.4, the modulo-(N+1) operation is effected three times after the modulo-N has been effected once. In the example shown in FIG. 1, the armature of the switch 42 is connected to the terminal B.sub.4. And the input condition of the AND circuit 21 in the digital oscillation section 14 is set to "A.sub.1.A.sub.2.A.sub.3.A.sub.4.A.sub.5.A.sub.6.A.sub.7 ". This means that the maximum length counter is set to modulo 112 (N=112). The basic pulse signal P generation state in this case is as indicated in the part (a) of FIG. 4. The numbers indicated in the part (a) of FIG. 4 are the numbers of clock pulses which are included in the ranges covered thereby, that is, the frequency division factors based on the clock pulses. As was described before, the submultiple frequency wave data Q.sub.2 through Q.sub.7 in succession with the basic pulse signal P are outputted by the AND circuit 41. Shown in the part (b) of FIG. 4 is the generation state of the submultiple frequency wave data trains D.sub.1, D.sub.2, D.sub.3 . . . each of which includes the basic pulse signal P at the top and the submultiple frequency wave data Q.sub.2 through Q.sub.7 in succession therewith as indicated in the part (f) of FIG. 3. As the submultiple frequency wave data Q.sub.2 having the smallest frequency division factor is obtained by subjecting the basic pulse signal P to 1/4 frequency division, its value is changed from "0" to "1" or from "1" to "0" whenever two basic pulse signals P are provided. Therefore, if it is assumed that the submultiple frequency wave data trains are generated with the generation period of the basic pulse signal P, the data trains having the same contents are provided continuously twice as D.sub.1, D.sub.1 ; D.sub.2, D.sub.2 ; . . . Although the circuitry may be so designed that each of the frequency division trains D.sub.1, D.sub.2, D.sub.3 . . . is generated only once, no trouble is caused even if the submultiple frequency wave data trains are provided continuously twice as was described above. As one example of the data contents of the frequency division data trains D.sub.1, D.sub.2, D.sub.3 . . . , the frequency division data Q.sub.2 and Q.sub.3 are indicated in the parts (c) and (d) of FIG. 4, respectively. The variations of the data contents of the frequency division trains D.sub.1, D.sub.2, . . . effected with the lapse of a longer period of time are indicated in Table 2 below:
TABLE 2
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Q.sub.2
Q.sub.3
Q.sub.4
Q.sub.5
Q.sub.6
Q.sub.7 Q.sub.2
Q.sub.3
Q.sub.4
Q.sub.5
Q.sub.6
Q.sub.7
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D.sub.1
0 0 0 0 0 0 D.sub.21
0 0 1 0
1 0
D.sub.2
1 0 0 0 0 0 D.sub.22 1 0 1 0 1 0
D.sub.3
0 1 0 0 0 0 D.sub.23 0 1 1 0 1 0
D.sub.4
1 1 0 0 0 0 D.sub.24 1 1 1 0 1 0
D.sub.5
0 0 1 0 0 0 D.sub.25 0 0 0 1 1 0
D.sub.6
1 0 1 0 0 0 D.sub.26 1 0 0 1 1 0
D.sub.7
0 1 1 0 0 0 D.sub.27 0 1 0 1 1 0
D.sub.8
1 1 1 0 0 0 D.sub.28 1 1 0 1 1 0
D.sub.9
0 0 0 1 0 0 D.sub.29 0 0 1 1 1 0
D.sub.10
1 0 0 1 0 0 D.sub.30 1 0 1 1 1 0
D.sub.11
0 1 0 1 0 0 D.sub.31 0 1 1 1 1 0
D.sub.12
1 1 0 1 0 0 D.sub.32 1 1 1 1 1 0
D.sub.13
0 0 1 1 0 0 D.sub.33 0 0 0 0 0 1
D.sub.14
1 0 1 1 0 0 D.sub.34 1 0 0 0 0 1
D.sub.15
0 1 1 1 0 0 D.sub.35 0 1 0 0 0 1
D.sub.16
1 1 1 1 0 0 D.sub.36 1 1 0 0 0 1
D.sub.17
0 0 0 0 1 0 .
D.sub.18
1 0 0 0 1 0 .
D.sub.19
0 1 0 0 1 0 .
D.sub.20
1 1 0 0 1 0 D.sub.128 1 1 1 1 1 1
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Among the wave data Q.sub.2 through Q.sub.7, the submultiple frequency wave data Q.sub.2 is repeatedly switched to "1" and "0" with the shortest period. Therefore, an oscillatory wave generated from the data Q.sub.2 is the highest in frequency. As is apparent from the numbers indicated in the part (a) of FIG. 4, the wave signal obtained from the data Q.sub.2 is one which is obtained by subjecting the delay flip-flop driving clock pulse to 1/451 frequency division. That is, the data Q.sub.2 is obtained by subjecting the basic pulse signal P to 1/4 frequency division, and in this example after the 1/112 frequency division of the clock pulse is carried out once, the 1/113 frequency division is carried out three times, so that four basic pulse signals P are provided. The signals obtained from the data Q.sub.3, Q.sub.4, Q.sub.5, Q.sub.6 and Q.sub.7 are those which are obtained by subjecting the highest frequency signal corresponding to the data Q.sub.2 to 1/2 , 1/4, 1/8, 1/16 and 1/32 frequency division, respectively. Thus, the data of a plurality of octavely-related wave signals are generated in a time division multiplexed way. The reason for the provision of the switch 42 to slightly change the frequency division factor is to provide slightly deviated frequency division factors which cannot be completely divided by using only the maximum length counter having the seven-stage shift register 16. In other words, if the AND circuit 21 is operated in the case when the maximum length counter operates on the modulo-N, then the data Q.sub.2 can be obtained with frequency division factors slightly different as 4N, (4N+1), (4N+2) and (4N+3). As is apparent from the above description whenever the basic pulse signal P is provided, the submultiple frequency wave data Q.sub.2 through Q.sub.7 arranged in a series mode are outputted by the multiplexed data generator section 11. These time-division multiplexed wave data signals are applied through the line 13 to a shift register 46 in the wave demultiplexing section 12. The shift register 46 and delay flip-flops in the section 12 are operated synchronously by the same clock pulse as that for the section 11. The shift register 46 has seven stages, and carries out a series shift operation in the direction of the first stage S.sub.1 toward the seventh stage S.sub.7. The basic pulse signal P and the wave data Q.sub.2 -Q.sub.7 are successively applied to the shift register 46 through the line 13. The shift register 46 operates to rearrange the series data Q.sub.2 -Q.sub.7 into parallel data Q.sub.2 -Q.sub.7, which are stored in a latch circuit 47. In this case, the basic pulse signal P is utilized as a timing signal controlling the latch timing of the latch circuit 47. Since the basic pulse signal P is delivered after the data Q.sub.2 through Q.sub.7, no signal is provided on the line 13 (the line 13 being at "0") for the period of at least six bit-times immediately before the provision of the basic pulse signal P. Accordingly, when the basic pulse signal P is inputted into the first stage S.sub.1 of the shift register 46, the outputs of the second through seventh stages S.sub.2 -S.sub.7 representative of the signal state of the six bit-times immediately before that are all at "0". This is indicated in correspondence to the timing t.sub.1 ' in FIG. 5. A NOR circuit 48 in the section 12 detects the time instant of the timing t.sub.1 ', that is, the time instant of arrival of the submultiple frequency wave data train D.sub.1 or D.sub.2 or D.sub.3 or . . . When the basic pulse signal P is inputted into the first stage S.sub.1 of the shift register 46, the output of the first stage S.sub.1 is raised to "1", while the output of an inverter 49 is switched to "0". As the output of the inverter 49 and the outputs of the second through seventh stages S.sub.2 -S.sub.7 are applied to the NOR circuit 48, the latter 48 provides the output "1" at the time instant of timing t.sub.1 '. The output "1" of the NOR circuit 48 is applied to the set terminal S of a set-reset type flip-flop 50. As a result, the flip-flop 50 is placed in a set state as indicated in the part (b) of FIG. 5, and its set output is applied to an AND circuit 52 after being delayed by one bit-time by a delay flip-flop 51 as indicated in the part (c) of FIG. 5. For the period from timing t.sub.1 ' to timing t.sub.7 ', the submultiple frequency wave data Q.sub.2 through Q.sub.7 are successively shifted in the stages S.sub.1 through S.sub.7 of the shift register 46, as shown in the part (a) of FIG. 5. At the timing t.sub.7 ', the basic pulse signal P is shifted to the seventh stage of the shift register 46, and all the submultiple frequency wave data Q.sub.7, Q.sub.6 . . . Q.sub.2 are held in the first through sixth stages S.sub.1 -S.sub.6, respectively. At the timing t.sub.7 ', the signal "1" (signal P) outputted by the seventh stage of the shift register 46 is applied to the reset input R of the flip-flop 50 and to the AND circuit 52. Therefore, the flip-flop 50 is reset as indicated in the part (b) of FIG. 5, while one bit-time later the output of the delay flip-flop 51 is decayed to "0". Accordingly, at the timing t.sub.7 ', the AND circuit 52 is still maintained enabled, and a latch signal L as indicated in the part (d) of FIG. 5 is applied to the latch circuit 47 by the AND circuit 52. In the latch circuit 47, the data Q.sub.7, Q.sub.6 . . . Q.sub.2 held in the first through sixth stages S.sub.1 -S.sub.6 of the shift register 46 are stored in a parallel mode in six memory position. Thus, the data Q.sub.2 -Q.sub.7 intermittently generated with the generation period of the basic pulse signal P are stored and held in the latch circuit 47, whereby they are converted into lasting signals. The levels ("1" and "0") of the signals outputted from the memory positions of the latch circuit 47 are changed whenever the levels of the data Q.sub.2 -Q.sub.7 applied through the line 13 are changed. Accordingly, six signals (square wave pulses) corresponding to six multiplexed data Q.sub.2 -Q.sub.7 outputted by the multiplexed data generator section 11 are individually outputted from the latch circuit 47, or the wave demultiplexing section 12. The parts (e) and (f) of FIG. 4 show the square wave signal outputted by the latch circuit 47 on the basis of the submultiple frequency wave data Q.sub.2 and Q.sub.3. FIG. 6 illustrates one example of the wave generator according to this invention, which is applied to a tone generator or an electronic musical instrument. In the case where the maximum number of simultaneously produced tones is n, musical tone production systems 53-1 through 53-n are provided for n tone production channels, respectively. The arrangement of the musical tone production system 53-1 only is roughly illustrated; however, the arrangements of the other musical tone production systems 53-2 through 53-n are similar to that of the system 53-1. A despressed key detecting circuit 55 operates to detect a depressed key in a keyboard 54 to supply information on the depressed key to a tone production assignment circuit 56. The tone production assigning circuit 56 is to assign the tone production of a depressed key to a suitable tone production channel. A key data KD of a depressed key is provided in correspondence to a tone production channel thus selected. The key data KD includes note data N.sub.1 . . . representative of the note of a depressed key assigned to the channel, octave data O.sub.1 . . . representative of the octave range of the key, and key-on data K.sub.1 whose level is raised to "1" when the key is maintained depressed, but is switched to "0" when the key is released. The key data are provided respectively for the channels, and a key data provided for a channel is utilized in the musical tone generation system (53-1 through 53-n) corresponding to the channel. For instance, the key data (the note data N.sub.1, the octave data O.sub.1, and the key-on data K.sub.1) of a key assigned to the first channel is utilized in the musical tone production system 53-1 corresponding to the first channel. The key data (the note data N.sub.2, the octave data O.sub.2, the key-on data K.sub.2) of a key assigned to the second channel is utilized in the musical tone production system 53-2 corresponding to the second channel. Similarly, the key data (the note data N.sub.n, the octave data O.sub.n, the key-on data K.sub.n ) of a key assigned to the n-th channel is utilized in the musical tone production system 53-n corresponding to the n-th channel. A channel processor described in the specification of U.S. Pat. No. 4,114,495 entitled "Channel Processor", assigned to the same assignee as the present case, or other suitable devices may be employed as the tone production assigning circuit 56. The key data KD for the channels are provided in time division manner by the tone production assigning circuit 56, and in this case the key data (N.sub.1, O.sub.1 and K.sub.1 ; N.sub.2, O.sub.2 and K.sub.2 ; . . . ; N.sub.n, O.sub.n and K.sub.n) concerning the channels are latched in the musical tone production system 53-1 through 53-n, where they are placed in static state before utilization, respectively. Circuits 11-1 through 11-12 each identical to the multiplexed data generator circuit 11 described with reference to FIG. 1 are provided for twelve (12) notes C.sup..music-sharp., D, . . . B and C, respectively. However, the multiplexed data generator circuits 11-1 through 11-12 are different from one another in the input connection state of the AND circuit 21 (FIG. 1) in the digital oscillator section 14 and the set state of the switch 42 (FIG. 1) adapted to slightly change the frequency division factor, so that the submultiple frequency wave data Q.sub.2 -Q.sub.7 corresponding to the musical tone frequencies of the notes C through C.sup..music-sharp. can be provided, in a multiplexed state, on respective output lines 13-1 through 13-12. One example of the input condition (A.sub.1 -A.sub.7) of the AND circuit 21 and the set position (B.sub.1 -B.sub.4) of the switch 42 in each of the sections 11-1 through 11-12 indicated in Table 3 below:
TABLE 3
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Frequency division factor
AND circuit 21
Note
Q.sub.2
1 2 3 4 N A.sub.1
A.sub.2
A.sub.3
A.sub.4
A.sub.5
A.sub.6
A.sub.7
Switch 42
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C 239
59 60 60 60 59 0 0 0 1 0 1 1 B.sub.4
B 253
63 63 63 64 63 1 1 1 0 0 0 0 B.sub.3
A.music-sharp.
268
67 67 67 67 67 1 0 0 0 1 1 1 B.sub.1
A 284
71 71 71 71 71 0 1 0 0 1 0 0 B.sub.1
G.music-sharp.
301
75 75 75 76 75 0 1 1 0 0 1 0 B.sub.3
G 319
79 80 80 80 79 1 0 1 1 0 1 1 B.sub.4
F.music-sharp.
338
84 85 84 85 84 1 0 1 1 0 1 0 B.sub.2
F 358
89 90 89 90 89 1 0 1 1 1 1 0 B.sub.2
E 379
94 95 95 95 94 1 0 0 0 1 1 0 B.sub.4
D.music-sharp.
402
100
101
100
101
100
1 0 0 1 0 1 1 B.sub.2
D 426
106
107
106
107
106
1 0 1 1 1 0 1 B.sub.2
C.music-sharp.
451
112
113
113
113
112
1 1 0 0 1 1 1 B.sub.4
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The number N indicating a frequency division factor in the above-described Table 3 is the period of the relevant submultiple frequency wave signal under the condition that the period of a clock pulse driving the shift registers etc. is taken as a unit. For instance, if the period of the clock pulse is about 1 .mu.s, then the period of a signal obtained from the data Q.sub.2 of the tone C is about 239 .mu.s, which is approximately 4184 Hz. This is the frequency of a note C.sub.8 in the 8-foot register. Furthermore, the period of a signal obtained from the data Q.sub.2 of the tone C.sup..music-sharp. is about 451 .mu.s, which is about 2217 Hz. This is the frequency of the note C.sup..music-sharp..sub.7 in the 8-foot register. Accordingly, signals having highest frequencies which are obtained from the data Q.sub.2 provided by the multiplexed data generator sections 11-1 through 11-12 are those of the note C.sup..music-sharp..sub.7, D.sup.7 , D.sup. .music-sharp..sub.7 . . . A.sup..music-sharp..sub.7, B.sub.7 and C.sub.8 in the 8-foot register. In Table 3, the column of "N" shows original frequency division factors obtained in the maximum length counter (i.e., the shift register 16 etc.) in response to the input connection state of the AND circuit 21. The columns of the number 1, 2, 3 and 4 show respective frequency division factors employed for producing the four basic pulse signals P. It will be noted that the respective frequency division factors for the same note are slightly different depending upon the set position of the switch 42. The column of Q.sub.2 shows a sum of the four frequency division factors, i.e., the submultiple frequency wave data Q.sub.2 corresponding to the highest frequency among the submultiple frequency wave data Q.sub.2 -Q.sub.7 for the respective notes supplied on the output lines 13-1 through 13-12. Each of the sections 11-1 through 11-12 provides six (6) submultiple frequency wave data Q.sub.2 -Q.sub.7 in a multiplexed state. In this connection, the submultiple frequency wave data Q.sub.3 through Q.sub.7 correspond to signals obtained by successively subjecting the wave data Q.sub.2 to frequency division. Accordingly, the wave data Q.sub.7 corresponding to the lowest frequency is a signal obtained by subjecting the data Q.sub.2 to 1/32 frequency division, and signals of tones (C.sup..music-sharp..sub.2, D.sub.2, D.sup..music-sharp..sub.2, . . . A.sup..music-sharp..sub.2, B.sub.2 and C.sub.3) lower by five octaves than the aforementioned highest frequency can be obtained from the data Q.sub.7. Accordingly, if it is assumed that the period of the clock pulse is 1 .mu.s in FIG. 6, the data Q.sub.2 through Q.sub.7 corresponding to the musical tone source signals ranging from the note C.sup..music-sharp..sub.2 to the note C.sub.8 in the 8-foot register are provided by each of the multiplexed data generator sections 11-1 through 11-12. The multiplexed submultiple frequency wave data Q.sub.2 through Q.sub.7 supplied to the lines 13-1 through 13-12 separately according to the notes are applied to the musical tone production systems 53-1 through 53-n, respectively. A note select circuit 57 in each of the musical tone production systems 53-1 through 51-n selects the multiplexed data Q.sub.2 -Q.sub.7 on a line (one of the lines 13-1 through 13-12) corresponding to the note of a tone assigned to the relevant channel, in accordance with the note data N.sub.1 (N.sub.2 . . . N.sub.n) supplied by the tone production assigning circuit 56. The multiplexed data Q.sub.2 through Q.sub.7 concerning single notes selected by the note select circuits 57 in the systems 53-1 through 53-n are applied to the wave demultiplexer sections 12-1 through 12-12, respectively. For instance, in the case where the tone C is assigned to the first channel, the note data N, represents the tone C, and therefore the multiplexed data Q.sub.2 -Q.sub.7 on the line 13-1 corresponding to the tone C are selected by the note select circuit 57 and are applied through the line 13A to the wave demultiplexer section 12-1. The arrangements of the wave demultiplexer sections 12-1 through 12-n are identical to that of the wave demultiplexer section 12 described with reference to FIG. 1. As was described before, in the wave demultiplexer 12-1 through 12-n, the individual wave data Q.sub.2 -Q.sub.7 are separately picked up and lathced from among the multiplexed wave data Q.sub.2 -Q.sub.7. Therefore, in correspondence to the wave data Q.sub.2 -Q.sub.7 of a single note name selected by the note select circuit 57, six octavely-related square wave tone source signals of the same note are provided in a parallel mode by the wave demultiplexed section 12-1 (- 12-n). For instance, if the tone C is assigned to the first channel, square wave signals having the frequencies of the note C.sub.3, C.sub.4, C.sub.5, C.sub.6, C.sub.7 and C.sub.8 in the 8-foot register are provided by the wave demultiplexer section 12-1 in correspondence to the wave data Q.sub.7, Q.sub.6, Q.sub.5, Q.sub.4, Q.sub.3 and Q.sub.2, respectively. The signals having the frequencies of the notes (hereinafter referred to as "note frequency signals", when applicable) in the octaves which are outputted by the wave demultiplexer sections 12-1 through 12-n are applied to tone keyers 58 in the musical tone production systems 53-1 through 53-n. In the tone keyers 58, according to the key-on data K.sub.1, K.sub.2, . . . K.sub.n of the tones assigned to the channels the note frequency signals of the respective octaves with an amplitude envelope characteristics such as attack and decay envelope characteristics are selected. The amplitude envelope characteristics such as attack and decay envelope characteristics can be provided by utilizing time constant circuits comprising capacitors and resistors, which are selectively charged and discharged according to the presence or absence of the key-on data K.sub.1 through K.sub.n. The six note frequency signals of the respective octaves, to which an envelope has been given, are applied to an octave select circuit 59, and the note signals of an octave range represented by the octave data O.sub.1 (O.sub.2 -O.sub.n) are selected separately according to a register footage. In this example, musical tones can be produced respectively in four footage registers: 2-foot (2'), 4-foot (4'), 8-foot (8') and 16-foot (16') registers. For instance, if it is assumed that the octave data O.sub.1 is representative of the first octave range, and the first octave range includes twelve tones C.sup..music-sharp..sub.3, D.sub.3, D.sup..music-sharp..sub.3 . . . A.sub.3, B.sub.3 and C.sub.4 ; then in the octave select circuit 59 of the first channel to which the tone C has been assigned, the signal having the frequency of the note C.sub.4 (corresponding to the data Q.sub.6) is selected as a musical tone signal in the 8-foot register, the signal having the frequency of the note C.sub.3 (corresponding to the data Q.sub.7) is selected as a musical tone signal in the 16-foot register, and the signals having the frequencies of the note C.sub.5 and C.sub.6 (corresponding to the data Q.sub.5 and Q.sub.4) are selected as musical tone signals in the 4-foot and 2-foot registers. Accordingly, if referred to a single footage register only, out of a plurality of signals having the same note which are in octave relation and are supplied, in a parallel mode, through the switching circuit 58, a single signal covered by the octave range represented by the octave data O.sub.1 is selected, and the single signal thus selected is provided, as the tone source signal of the tone (key) assigned to the relevant channel. The tone source signals provided by the musical tone production system 53-1 through 53-n are subjected to mixing separately according to the footage registers, and are supplied to a tone color controlling filter circuit (not shown). One example of the note select circuit 57 is shown in FIG. 7. The note data N.sub.1 is applied in time division manner, for instance, in the form of a 4-bit code signal. This code signal is decoded by a decoder 60, and thereafter is latched by a latch circuit 61. Among the outputs of the latch circuit 61, only one output corresponding to the note represented by the note data N.sub.1 is at "1". Twelve AND circuits 62 are provided respectively for the notes, and only one of the twelve AND circuits 62 is enabled in response to the output of the latch circuit 61. Multiplexed wave data supplying lines 13-1 through 13-12 corresponding to the notes are connected to the AND circuits 62, respectively, so that the signal on a single line (one of the lines 13-1 through 13-12) corresponding to a single note is selected by a single AND circuit 62. The outputs of the AND circuits 62 are applied through an OR circuit 63 to a line 13A, and are then applied to the wave demultiplexing section 12-1. One example of the tone keyers 58 and the octave select circuit 59 is shown in FIG. 8. The key-on data K.sub.1 supplied in time division manner is latched by a latch circuit 63, where it is converted into a direct current. When the key-on data K.sub.1 is raised to "1" upon key depression, a field-effect transistor 64 is rendered conductive to charge the capacitor 65. When the key-on data K.sub.1 is switched to "0" upon key release, the field-effect transistor 64 is rendered non-conductive, as a result of which the capacitor 65 is discharged through a resistor 66. Accordingly, an envelope shape voltage characterizing the attack, sustain and decay of a musical tone amplitude is provided to a line 67. Square wave submultiple frequency wave signals corresponding to the wave data Q.sub.2 -Q.sub.7 outputted by the wave demultiplexer section 12-1 render field-effect transistors 68-1, 68-2, . . . conductive to select the ground voltage, when at the level "0"; on the other hand, they render field-effect transistors 69-1, 69-2, . . . conductive to select the envelope shape voltage on the line 67, when at the level "1". Thus, the levels of the submultiple frequency wave signals are scaled by the envelope shape voltage on the line 67 and are then applied to the octave select circuit 59. The octave data O.sub.1 is, for instance, a 2-bit code signal, which is decoded separately according to the octave ranges by a decoder 70 and are held by a latch circuit 71. Field-effect ransistors 73, 74, 75 . . . are provided so that the wave signals of the relevant octave range can be selected with the aid of the signals on octave selection lines 72-1 through 72-4 for every footage register. For instance, with the aid of the signal "1" on the first octave selection line 72-1, the field-effect transistors 73 and 74 are rendered conductive, as a result of which the wave signal corresponding to the wave data Q.sub.7 is selected as a signal of the first octave range in the 16-foot register (16'), and the wave signal corresponding to the wave data Q.sub.6 is selected as a signal of the first octave range in the 8-foot register (8'). FIG. 9 shows another example of the wave generator according to the invention, which is applied to a tone generator of an electronic musical instrument. The circuitry of FIG. 9 is almost similar to that of FIG. 6. That is, the former is mainly different from the latter in the following points: octave demultiplexer sections 80-1 through 80-n are provided at the past stages of the note select circuits 57-1 through 57-n, respectively, so that among the multiplexed wave data Q.sub.2 -Q.sub.7, which are the outputs of the note select circuits 57-1 through 57-n, the data (Q.sub.2 -Q.sub.7) of tone ranges specified by the octave data O.sub.1 through O.sub.n are selected. FIG. 10 illustrates one example of the octave demultiplexer section 80-1. The arrangements of the other octave demultiplexer sections 80-2 through 80-n are identical to that of the section 80-1. The multiplexed wave data Q.sub.2 through Q.sub.7 of a note selected by the note select circuit 57-1 are applied through a line 13A to the first stage S.sub.1 in a shift register 91. The shift register 91 and delay flip-flops in the octave demultiplexer section 80-1 (80-2 through 80-n) are synchronously operates with the aid of the same clock pulse as that employed for the multiplexed data generator sections 11-1 through 11-12. The shift register 91 is a 7-stage/1-bit shift register which carries out a series shift operation from the first stage S.sub.1 to the seventh stage S.sub.7. Accordingly, the basic pulse signal P at the top and the wave data Q.sub.2 -Q.sub.7 in succession therewith, which are successively inputted, are successively shifted from the first stage S.sub.1 toward the seventh stage S.sub.7 as indicated in the part (a) of FIG. 11. The wave data Q.sub.2 through Q.sub.7 superposed in a series mode are converted into parallel wave data by the shift register 91. The outputs of the first through third stages S.sub.1 -S.sub.3 in the shift register 91 are connected to the input terminals of a latch circuit 92, respectively. The latch circuit 92 operates to latch a wave data (one of the data Q.sub.2 -Q.sub.7) corresponding to a tone range specified by the octave data O.sub.1 and to convert it into a submultiple frequency wave data in a static state (or in the state of an ordinary frequency division signal). In this example, tone source signals in the 8, 4 and 2 foot registers can be provided, and therefore the memory position of the latch circuit 90 is of 3-bits for each footage register. However, if a single footage register is employed, the meory position may be of 1-bit. A signal obtained by inverting the output of the first stage S.sub.1 in the shift register 91 by an inverter 94, and the outputs of the second through seventh stages S.sub.2 -S.sub.7 are applied to a NOR circuit 93. The NOR circuit 93 is to detect the basic pulse signal P (that is, it is to detect the arrival of the wave data trains D.sub.1, D.sub.2, . . . ). The outputs of the fourth through seventh stages S.sub.4 -S.sub.7 are connected to AND circuits 98 through 101, respectively. These AND circuits 98 through 101 are to dynamically select a wave data (one of the data Q.sub.2 -Q.sub.7) corresponding to a tone range specified by the octave data O.sub.1. For instance, if the octave data O.sub.1 is supplied, in the form of a code signal, in time division manner from the tone production assigning circuit 56, then the octave data O.sub.1 is decoded by the decoder 89 separately according to the octave ranges. The output of the decoder 89 is latched, where it is placed in a static state. One of the octave select data OS.sub.1, OS.sub.2, OS.sub.3 and OS.sub.0 thus obtained through decoding is raised to "1". The relationships among the octave data O.sub.1, the octave select data OS.sub.1, OS.sub.2, OS.sub.3 and OS .sub.0 obtained by decoding the octave data O.sub.1, and tone ranges are indicated in Table 4. The tone ranges indicated in Table 4 are based on the 8-foot register.
TABLE 4
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O.sub.1 Decode Output Tone Range (8')
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0 1 OS.sub.1 C.music-sharp..sub.2 -C.sub.3
1 0 OS.sub.2 C.music-sharp..sub.3 -C.sub.4
1 1 OS.sub.3 C.music-sharp..sub.4 -C.sub.5
0 0 OS.sub.0 C.music-sharp..sub.5 -C.sub.6
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The tone ranges C.sup..music-sharp..sub.2 -C.sub.3, C.sup..music-sharp..sub.3 -C.sub.4, C.sup..music-sharp..sub.4 -C.sub.5, and C.sup..music-sharp..sub.5 -C.sub.6 will be referred to as first, second, third and fourth tone ranges, respectively. In the case where the octave data O.sub.1 is supplied in a static state by the tone production assigning circuit 56, the provision of the latch circuit 90 is unnecessary. The octave select data OS.sub.1 corresponding to the first tone range is applied to the AND circuit 101, and the octave select data OS.sub.2 corresponding to the second tone range is applied to the AND circuit 100. The octave select data OS.sub.3 corresponding to the third tone range is applied to the AND circuit 99, and the octave select data OS.sub.0 corresponding to the fourth tone range is applied to the AND circuit 98. Accordingly, a single AND circuit (one of the AND circuits 98 through 101) corresponding to a tone range specified by the octave data O.sub.1 (that is, the tone range of a tone assigned to the relevant channel) is enabled. When the basic pulse signal P is shifted to a stage (one of the stages S.sub.4 -S.sub.7) corresponding to the AND circuit (98-101) thus enabled, the AND circuit operates so as to apply the output "1" to the OR circuit 102. The arrival of the basic pulse signal P, that is, the arrival of the frequency division data Q.sub.2 -Q.sub.7 is detected as follows: As the wave data Q.sub.2 -Q.sub.7 are delivered after the basic pulse signal P at all times, no signal is applied to the line 13A for the period of at least six bit-times immediately before the arrival of the basic pulse signal P (the line being at "0"). Therefore, when the basic pulse signal P is inputted into the first stage S.sub.1 in the shift register 91, the outputs of the second stage S.sub.2 through the seventh stage S.sub.7, which represent the signal state of the six bit-times immediately before that are all at "0". This is indicated in correspondence to the timing t.sub.1 '. When the basic pulse signal P is inputted into the first stage S.sub.1 in the shift register 91, the output of the first stage S.sub.1 is raised to "1", while the output of the inverter 94 is switched to "0". The output of the inverter 94 and the outputs of the second through seventh stages S.sub.2 -S.sub.7 are applied to the NOR circuit 93. The NOR circuit 93 provides the output " 1" at the time instant of the timing t.sub.1 '. The output of the NOR circuit 93 is applied to the set input terminal S of a reset-set type flip-flop 95. As a result, the flip-flop 95 is placed in a set state as indicated in the part (b) of FIG. 11, and its set output, after being delayed by the delay flip-flop 96 as indicated in the part (c) of FIG. 11, is applied to an AND circuit 97, as a result of which the latter 97 is enabled. The outputs of the above-described AND circuits 98 through 101 are applied through the OR circuit 102 to the other input terminal of the AND circuit 97, and to the reset input terminal R of the flip-flop 95. As the basic pulse signal P goes before the wave data Q.sub.2 -Q.sub.7 at all times, when the signal "1" is provided by the AND circuits 98-101 with the aid of the basic pulse signal P, an initial reset signal is applied to the flip-flop 95 to reset the latter 95. At the same time, the AND condition of the AND circuit 97 is satisfied, and the output "1" of the AND circuit 97 is applied to the strobe input terminal (S) of the latch circuit 92. When the flip-flop 95 is reset, one bit-time later the output of the delay flip-flop 96 is switched to "0". Therefore, even if the output "1" is provided by the OR circuit 102 thereafter, the AND circuit 97 does not operate. Accordingly, the strobe pulse SP which is applied to the latch circuit 92 by the AND circuit 97 is provided only for the period of one-bit time. The timing with which the strobe pulse SP occurs is determined by the octave select data OS.sub.1, OS.sub.3 and OS.sub.0. In the case where the octave select data OS.sub.0 is at "1", the AND circuit 98 operates when the basic pulse signal P is inputted into the fourth stage S.sub.4 in the shift register 91, and the strobe pulse SP is provided at the timing t.sub.4 ' (the part (d) of FIG. 11). Therefore, the frequency division data Q.sub.4, Q.sub.3 and Q.sub.2 are inputted from the stages S.sub.1 -S.sub.3 of the shift register 91 into the latch circuit 92 (cf. the part (a) of FIG. 11). Whenever the wave data Q.sub.1 -Q.sub.7 is applied, or whenever the wave trains D.sub.1, D.sub.2, D.sub.3 . . . (cf. Table 2) together with the basic pulse signal P are applied, the data contents of the wave data Q.sub.4, Q.sub.3 and Q.sub.2 stored in the latch circuit 92 are rewritten. The levels ("1" and "0") of the signals outputted from the memory positions in the latch circuit 92 are changed whenever the logical levels of the wave data Q.sub.2 -Q.sub.4 applied through the line 13A are changed. Accordingly, only the square-wave-like tone source signal corresponding to the wave data Q.sub.2 -Q.sub.4 of the tone range actually produced in the wave data provided by the multiplexed data generator sections 11-1 through 11-12, is outputted by the latch circuit 92. The parts (e) and (f) of FIG. 5 are to indicate that the output of the latch circuit 47 is a square wave, and illustrates square wave tone source signals which are outputted by the latch circuit 92 by basing on the wave data Q.sub.2 and Q.sub.3. Incidentally, the output signal of the memory position in the latch circuit 92, which has latched the data of the first stage S.sub.1 in the shift register 91, is outputted, as a tone source signal in the 8-foot register, through a line 81. In this example, as the wave data Q.sub.2 -Q.sub.7 are converted into direct current signals in the order of increasing frequency division factor, the frequency division data higher by one octave than that in the first stage S.sub.1 in the second stage S.sub.2 of the shift register 91. Accordingly, the output signal of the memory position in the latch circuit 92, which has latched the data of the second stage S.sub.2, corresponds to a tone source signal in the 4-foot register, and it is outputted through the line 72. As the frequency division data higher by one octave than that in the second stage S.sub.2 is inputted into the third stage S.sub.3, the output signal of the memory position in the latch circuit 92, which has latched the data of the third stage corresponds to a tone source signal in the 2-foot register, and it is outputted through the line 83. In the case where the octave select data OS.sub.3 representative of the third tone range is at "1", the strobe pulse SP is provided when the basic pulse signal P is inputted into the stage S.sub.5 in the shift register 91. Therefore, as indicated in the part (e) of FIG. 11, at the timing t.sub.5 ' the strobe pulse SP is produced, and the wave data Q.sub.5, Q.sub.4 and Q.sub.2 are latched by the latch circuit 92. In the case where the octave select data OS.sub.2 representative of the second tone range is at "1", when the basic pulse signal P is inputted into the sixth stage S.sub.6 of the shift register 91, the AND circuit 100 operates, as a result of which the strobe pulse SP is produced as indicated in the part (f) of FIG. 11, and the frequency division data Q.sub.6, Q.sub.5 and Q.sub.4 are latched by the latch circuit 92. In the case where the octave select data OS.sub.1 representative of the first tone range is at "1", when the basic pulse signal P is inputted into the seventh stage of the shift register 91, the AND circuit 101 operates, as a result of which the strobe pulse SP is provided at the timing t.sub.7 ' as indicated in the part (g) of FIG. 11. Thus, the wave date Q.sub.7, Q.sub.6 and Q.sub.5 inputted into the first through third stages S.sub.1 -S.sub.3 of the shift register 91 (cf. the timing t.sub.7 ' in the part (a) of FIG. 11) are latched by the latch circuit 92. As is apparent from the above description, in the octave demultiplexer circuit 80-1 (80-2-80-n), only the frequency division signal of the tone range corresponding to the octave data O.sub.1 (O.sub.2 -O.sub.n) is outputted through the line 81 (or 82 or 83). The wave signals of the other tone ranges may exist as the wave data Q.sub.2 -Q.sub.7 multiplexed in a series mode, but cannot exist as submultiple frequency wave signals which can be individually utilized immediately. In the above-described example, as the number of the footage registers is plural, the latch circuit 92 has a plurality of bits so as to provide a plurality of submultiple frequency wave signals. However, in this case, unlike the conventional case, no unnecessary submultiple frequency wave signals are produced. If the number of footage registers is made to be only one, then the latch circuit 92 may be of a single bit, so as to produce only the submultiple frequency wave signal of a single octave range. The submultiple frequency wave signals (square wave tone source signals) generated by the octave demultiplexer sections 80-1 through 80-n are applied to the tone keyers 58-1 through 58-n, respectively. In the tone keyers 58-1 through 58-n of the channels, the tone source signals are keyed(gated) according to the key-on data K.sub.1, K.sub.2 . . . K.sub.n of the tones assigned to the channels. The tone source signals outputted by the tone keyer circuits 58-1 through 58-n are subjected to mixing in the respective musical tone generating systems 53-1 through 53-n, separately according to the footage registers, and are supplied to the tone color filters (not shown).
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