JPS581790B2 - Denshigatsukino Vibra-Toseigiyosouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibrato control device for a tone generator used in an electronic musical instrument.

As shown in an example in FIG. 1, the digital tone generator drives a maximum cycle count consisting of a shift register 1, a NOR circuit 2, an exclusive OR circuit 3, and an OR circuit 4 using a master clock pulse φ. A digital numerical signal corresponding to the note selected by the keyboard switch circuit 5 is read from the read-only memory 6, and a comparator 7 compares this digital numerical signal with the contents of the maximum period quanta (parallel output of the shift register 1). When the two match, the shift register 1 is reset.

The match detection output of the comparator 7 is delayed by one pulse φ clock by a delay flip-flop 8, and is applied to the shift register 1 as a reset signal. It is output from the output terminal 9 as a frequency signal.

Note that if the shift register 1 is reset the moment a match is detected by the comparator 7, a slight delay may cause malfunction, so a 1-bit delay flip-flop 8 is provided to reset the shift register 1 with a 1-bit time delay from the time a match is detected. I try to do it.

Therefore, the delay flip-flop 8 plays the role of a buffer circuit to prevent malfunction.

Next, a brief explanation will be given of how the master clock pulse φ is divided into a desired frequency in the tone generator shown in FIG.

When one tone is selected by the keyboard switch circuit 5, a digital numerical signal corresponding to that tone (note name) is read out from the read-only memory 6.

On the other hand, since the contents of the parallel outputs of each stage of the shift register 1 change every moment at the timing of the master clock pulse φ, the contents of the register 1 and the read-only memory 6 change during one cycle of the change in the contents of the register 1. There are cases where the read contents always match once.

For example, if the comparator 7 detects a match when n clock pulses φ are added to shift register 1, counting from when the contents of shift register 1 are all 0, then every n+1 clock pulses φ occur. A reset signal is applied to the shift register 1, and the frequency-divided output corresponds to the frequency of the touch sound selected by the master cross switch circuit 5.

Assuming that the shift register 1 has 9 bits and the 5th and 9th bits are connected to the exclusive OR circuit 3 as shown in the figure, the contents of the shift register 1 are changed as shown in Table 1 every time a pulse φ is added. changes.

Further, if the content of the digital numerical value read out from the read-only memory 6 in response to the selection of the keyboard switch circuit 5 is, for example, 100001000, it matches the content of the sixth item in Table 1.

Therefore, when six pulses φ are added, the comparator 7 detects a match, the match detection output ID becomes "1", and the shift register 1 is reset with a delay of one pulse.

Therefore, in this case, a reset signal is repeatedly generated every time seven pulses φ are applied and taken out from the master terminal 9.

In this way, a frequency signal with a desired pitch is obtained.

In the tone generator having the above configuration, vibrato is conventionally applied to the generated sound (frequency-divided output) by modulating the frequency of master clock pulse φ by the vibrato frequency.

However, the oscillation frequency of master clock pulse φ is 2MH
z, and modulating this has the disadvantage of lacking frequency stability and decreasing accuracy.

SUMMARY OF THE INVENTION An object of the present invention is to enable a digital tone generator to apply vibrato without modulating the frequency of the master clock pulse.

This invention uses the coincidence detection output ID of the comparator 7, that is, the output of the delay flip-flop 8, as a reset signal for the soft register 1 with an appropriate delay, thereby shifting the reset timing according to the delay time. Modulation of the branch output is achieved by cyclically varying the delay time according to the vibrato frequency, whereby the reset timing is periodically shifted to obtain a vibrato-applied frequency-divided output. It is.

Further, the present invention is characterized in that the depth of vibrato can be adjusted in a tone generator that can apply vibrato without modulating the frequency of the master clock pulse.

This can be realized by changing the variation width of the delay time using a switch or the like.

Further, the present invention is characterized in that in a tone generator capable of applying vibrato without modulating the frequency of the mask clock pulse, the depth of the vibrato can be applied vertically asymmetrically.

When the vibrato depths are vertically symmetrical around the normal pitch, the average pitch that the human ear can hear is generally more pronounced than the normal pitch.

Therefore, if you adjust the depth of the vibrato vertically asymmetrically so that the modulation depth is deeper in the higher part than the normal pinch and the modulation depth is shallower in the lower part, you can hear the vibrato sound according to the original pitch. can.

That is, according to the present invention, there is provided a counting means whose contents are sequentially changed from an initial value in accordance with a clock pulse, and a value in which the contents of this counting means are different from the initial value by a value corresponding to a predetermined pitch. and a discharge means for detecting this, and the detection output of the detection means is used as an initial value setting signal of the counting means to obtain an output pulse of a desired cycle according to the initial value setting timing of the counting means. In a tone generator of an electronic musical instrument, a first device sequentially delays the detection output of the detection means in a plurality of stages, and a plurality of delay outputs obtained by the first device with different delay times are delayed at a speed related to a vibrato frequency. and a second device that supplies the selected delay output to the counting means as an initial value setting signal, so as to apply vibrato by periodically shifting the initial value setting timing. I have to.

Further comprising a selection device that divides the delayed output of each stage obtained by the first device into a plurality of combinations and selects a desired single combination to be selected by the second device, The vibrato depth can be adjusted by appropriately selecting a combination of delay times of the delayed outputs used as the initial value setting signal.

Further, in each of the delay outputs to be selected by the second device, the difference between the earliest delay time and the standard delay time corresponding to the normal pitch is the difference between the latest delay time and the standard delay time. It is set to be larger than that of the normal pinch, so that the modulation degree on the higher frequency side is deeper than the modulation degree on the lower frequency side than the normal pinch.

The invention will now be described in detail with reference to the embodiments of the accompanying drawings.

In the tone generator 10 of FIG. 2, the same devices as those in FIG. 1 are designated by the same reference numerals for convenience.

The vibrato adding device 11 inserted between the delay flip-flop 8 and the reset input side of the soft register 1 is
Coincidence detection output ID of comparator 7 (delay flip-flop 8
Shift register 1 for delaying the output of
2 and a circuit for sequentially and repeatedly selecting delayed outputs of each stage and supplying the selected delay outputs to the reset input of the shift register 1.

Soft register 12 is, for example, 2 bits and sequentially shifts the output of delay flip-flop 8 according to master clock pulse φ, producing delayed outputs on lines 14 and 15 sequentially.

Therefore, the output line 13 of the delay flip-flop 8 is led and the output lines 14, 15 of the shift register 12.
The signals are sequentially shifted by one bit time.

n counting from when the contents of shift register 1 are all O
When master clock pulses φ are added to the shift register 1, the contents of the shift register 1 (counter) (
For example, if the comparator 7 detects that the content of the digital signal read out from the read-only memory 6 (9 bits) matches the content of the digital signal read from the read-only memory 6, then when the shift register 1 (counter) counts n+1 pulses φ, the line The output of line 13 becomes "1", when 1,002 pieces are counted, the output of line 14 becomes "1", and when n+3 pieces are counted, the output of line 15 becomes "1".
The output of becomes "1".

The signal on line 13, 14 or 15 is in shift register 1
Considering the case where the reset signal becomes
It becomes as shown in the column.

As is clear from column A of Table 2, the signals on lines 13, 14 and 15, which have sequentially different delay times, correspond to different frequency division ratios, and which line (13 to 15) is used as the reset signal for shift register 1. ) The frequency-divided output changes slightly depending on which signal is used.

For example, the frequency of the outer peripheral output coupler φ obtained when the signal on line 14 is used as a reset signal, m=n+
2), the divided output fc/(m-1) obtained from the output terminal 9 when the outer peripheral output of each line 13 to 15 is used as a set signal as shown in column B of Table 2 is the reference frequency. fc/m, and the divided output fc/(m+1) obtained when line 15 is used as a reset signal is lower than the reference frequency.

Of course, the content of the digital numerical value read from the read-only memory 6 is set to a value that corresponds to the regular pitch of the reference branch output sound.

When the vibrato switch 16 is turned on, a signal "1" is applied to the reset input of the shift register 17, and the contents of the register 17 are reset.

When all the outputs of the shift register 17 become "0", the output of the NOR circuit 18 becomes "1", and the AND circuit 19 becomes operational.

Each output line 20, 2 of the 3-bit shift register 17
AND circuits 23, 24, to which 1 and 22 are connected, respectively.
Since line 25 is inoperable, only the signal on line 14 is sent to shift register 1 via AND circuit 19 and OR circuit 26.
connected to the reset input of

Therefore, it does not apply in this case.

To apply vibrato, turn off the vibrato switch 16 as shown.

The shift register 17 is not reset and the NOR circuit 18
The signal "1" read from the line 20.21 is sequentially shifted according to the oscillation pulse VP of the vibrato oscillator 27.
and 22, a signal "1" is sequentially generated.

When the lines 20 to 22 all become "0", the output of the NOR circuit 18 becomes "1" again, and the signal "1" is read into the shift register 17.

In this way, lines 30 (output of NOR circuit 18), 20, 21 and 22 become repeating signals "1" in order according to the speed of vibrato clock pulse VP, and accordingly, AND circuits 19, 23, 24 and 25 Can be operated repeatedly in sequence.

First, the signal on line 14 becomes a reset signal for shift register 1 by the operation of AND circuit 19, then the signal on line 15 becomes a reset signal by operation of AND circuit 23, and then the signal on line 14 becomes a reset signal by operation of AND circuit 24.
The signal on line 4 becomes a reset signal, and then, by the operation of AND circuit 25, the signal on line 13 becomes a reset signal.

In this way, the delay line used as a reset signal is switched periodically as lines 14→15→14→13, etc., and the frequency of the divided output changes periodically as follows.

Since the normal changes in this way, vibrato is applied.

One period of change in the divided output (changes in 4 ways) corresponds to a vibrato period, so if you want to apply a 7Hz vibrato, for example, use the oscillation pulse VP of the vibrato oscillator 27.
may be set to 28Hz.

Therefore, the AND circuits 19, 23, 24, which become operable,
25 are switched in sequence at a rate of 2 8 Hz.

Generally, the speed at which the signal "1" appears on line 13, 14 or 15 (the pitch of the generated sound) is much faster.

Note that the shift registers 12 and 17 can also be configured with appropriate counters, decoders, etc.
The number of stages of shift registers 12 and 17 can also be increased as appropriate.

FIG. 3 shows another embodiment of the invention, in which the depth of vibrato can be variably adjusted.

Although only the parts related to the vibrato adding circuit 11 are shown, other circuit parts not shown are the same as the corresponding parts in FIG.

In the vibrato adding circuit 11 shown in FIG. 3, the output of the delay flip-flop 8 is transferred to a 4-bit shift register 121.
, and are sequentially shifted according to the master clock pulse φ.

Output line 13a of delay flip-flop 8 and output lines 13b, 14, 15 of each stage of soft register 121
The timings of b and 15a are each shifted by one bit time (sequentially delayed).

Therefore, each line 13a, 13b, 14, 15b and 1
Considering the case where the signal 5a is used as a reset signal for shift register 1 (Fig. 2), the division ratio will be as shown in column A of Table 3, and if n+3=m with line 14 as the reference, the division output will be: The results are as shown in column B of Table 3.

As in Table 2, fc is the frequency of the mask clock pulse φ.

Of course, as described above, the contents of the read-only memory 6 are set so that when the signal on the line 14 is used as a reset signal, a branched output with a normal pitch is obtained.

As is clear from column B of the table above, the divided output of line 13a is higher than the divided frequency of line 13b, and the divided output of line 15a is lower than the outer frequency of line 15b.

Accordingly, lines 13b, 14 and 15. When adding vibrato with combination b, the vibrato depth becomes shallow,
When adding vibrato using a combination of lines 13a, 14, and 15a, the vibrato depth becomes deeper.

Switches 28 and 29 are used to change the vibrato depth.

The switches 28 and 29 are interlocking switches, and the first mode of switching connection is the state in which the lines 13b and 15b are connected to the common lines 13 and 15, as shown in the figure.
The second aspect realized by switching this is the common line 13
and 15 are connected to lines 13a and 15a.

Therefore, a much shallower vibrato effect is obtained in the first connection mode.

Also, as shown in the second connection diagram b, a deep vibrato is obtained.

Note that by further increasing the number of stages of the shift register 121 and increasing the number of delay stages, it is possible to switch and set the vibrato depth to various types.

FIG. 5 shows still another embodiment of the present invention, in which the average pitch heard by humans is brought closer to the normal pitch of the note selected by the keyboard switch circuit 5 by applying the vibrato depth asymmetrically in the vertical direction. It has been made possible to do so.

Similar to FIG. 3, only the parts related to the vibrato adding circuit 11 are shown, but other circuit parts not shown are the same as the corresponding parts in FIG.

In the vibrato adding circuit 11 shown in FIG.
, and are sequentially shifted according to the master clock pulse φ.

Output line 13a of delay flip-flop 8 and output lines 13a, 14 and 1 of each stage of shift register 122
The timings of the signals appearing in 5 are each shifted by 1 bit time (sequentially delayed).

Therefore, if we consider the case where the signals on each line 13a, 13b, 14 and 15 are respectively used as reset signals for shift register 1 (FIG. 2), the frequency division ratio will be as shown in column A of Table 4, and the line 14 n +3 based on
= m, the branch outputs will be as shown in column B of Table 4.

fc is the frequency of master clock pulse φ.

Similarly, in this embodiment, when the signal on the line 14 is used as a reset signal for the shift register 1, it is possible to obtain a branched output at the normal pitch of the tone selected by the keyboard switch circuit 5 (FIG. 2). The contents of the read-only memory 6 are set as follows.

However, the reference line 14 is not located at the center of the delay times of the antinodal stages, but is biased toward longer delay times (line 15).

The timing difference between line 13a with the shortest delay time (or no delay) and reference line 14 is 2 bit times, but the difference between line 15 with the longest delay time and reference line 14 is 1 bit time. It's time.

As already evident, shorter delay times result in higher pitched branch outputs, and longer delay times result in lower pitch branched outputs.

Therefore, as is clear from column B of Table 4, line 14
Considering the regular pitch corresponding to line 13
The amount of change is larger in the higher (upper) pitch corresponding to line a than in the lower (lower) pitch corresponding to line 15.

Therefore, as shown in FIG. 5, the signal on line 13b whose delay time is symmetrical with that of line 15 is not used, and line 13a is sent to AND circuit 25, line 14 is sent to AND circuits 19 and 24, and line 15 is sent to AND circuit 25. is connected to the AND circuit 23.

That is, lines 13a and 15 whose delay times are asymmetrical with respect to line 14 are used.

Therefore, the shift register 17 is shifted according to the vibrato clock pulse VP, and the AND circuits 19, 23.2
4 and 25 can be operated repeatedly in sequence, line 1
4, 15, 14, 13a, . . . , the lines serving as reset signals for the shift register 1 are periodically switched in order, and the frequency of the divided output obtained from the output terminal 9 is periodically changed as follows.

In this way, it is possible to apply a vertically asymmetrical vibrato depth in which the amount of change in the sixth (higher) pitch is large and the amount of change in the lower (lower) pitch is small.

This vertically asymmetrical vibrato is corrected by the human ear.

Note that the number of stages of the shift register 122 or the upper limit delay time (corresponding to line 15) and lower limit delay time (corresponding to line 13a)
It goes without saying that the difference between the two values (equivalent to

Further, as in the example shown in FIG. 3, it is also possible to adjust the vibrato depth by means of a switch or the like.

However, in this case, it is of course necessary to always take care to ensure that the difference between the shortest delay time and the reference delay time is greater than the difference between the longest delay time and the reference delay time. It is not particularly shown in Figures 5 and 5 because it can be easily configured.

Note that if tone generators 10 as shown in FIGS. 2, 3, and 5 are provided for each of the 12 scale notes, different vibrato can be applied to each note name.

As explained above, the present invention enables vibrato to be applied without modulating the frequency of the mask clock pulse, thereby eliminating various drawbacks caused by the conventional method of modulating the frequency of the master clock pulse with the vibrato frequency. is removed.

Further, the vibrato depth can be easily adjusted by operating a switch or the like, and the vibrato depth can also be easily adjusted vertically asymmetrically, which is preferable to the auditory sense.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional tone generator, FIG. 2 is a block diagram showing an embodiment of the present invention,
FIG. 3 is a block diagram showing another embodiment of the present invention, in which the vibrato depth can be adjusted; FIG. 4 is a graph showing an example in which the vibrato depth is adjusted in two ways;
The figure is a block diagram showing still another embodiment of the present invention, in which the vibrato depth is set vertically asymmetrically, and FIG. 6 is a graph showing the state of vertically asymmetrical vibrato. 10... Tone generator, 11... Vibrato addition circuit, 12, 121, 122... Shift register, 16
...Vibrato switch, 17...Shift register, 2
7...Vibrato oscillator, 28, 29...Vibrato depth selection switch.

Claims (1)

[Claims] 1. Counting means whose contents are sequentially changed from an initial value in accordance with clock pulses, and the contents of this counting means have become a value that is different from the initial value by a value corresponding to a predetermined pitch. and a detection means for detecting the detection means, and uses the detection output of the detection means as an initial value setting signal of the counting means to obtain an output pulse of a desired cycle according to the initial value setting timing of the counting means. The tone generator includes a first device that sequentially delays the detection output of the detection means in a plurality of stages, and a plurality of delayed outputs obtained by the first device with different delay times at a speed related to the vibrato frequency. a second device that sequentially and periodically selects the delay output and supplies the selected delay output to the counting means as an initial value setting signal, and vibrato is applied by periodically shifting the initial value setting timing. Vibrato control device for electronic musical instruments. 2. Divide the delayed outputs of each stage obtained by the first device into a plurality of combinations, select a desired single combination, and
further comprising a selection device for selection in the device;
2. The vibrato control device according to claim 1, wherein the vibrato depth can be adjusted by appropriately selecting a combination of delay times of delayed outputs used as the initial value setting signal. 3 In each of the delay outputs to be selected by the second device, the difference between the fastest delay time and the reference delay time corresponding to the normal pitch is the difference between the slowest delay time and the reference delay time. 2. The vibrato control device according to claim 1, wherein the vibrato is set to be larger than the normal pitch, and the modulation degree on the higher frequency side than the normal pitch is deeper than the modulation degree on the lower frequency side.