JP2834280B2 - Electronic musical instrument tone control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a musical tone control device for an electronic musical instrument that mixes musical tone signals as digital signals.

2. Description of the Related Art In a conventional electronic musical instrument, tone signals generated by a plurality of tone signal generating means are once converted from digital signals to analog signals, mixed, and output.

Alternatively, tone signals are mixed as digital signals only between a plurality of tone signal generating means and tone signal mixing means operating with the same basic clock signal. (See, for example, JP-A-53-83610) Problems to be Solved by the Invention However, in the above-mentioned conventional electronic musical instrument, in order to convert a digital signal into an analog signal, the number of digital signals is equal to the number of tone signal generating means. -Analog converter
DAC), which is expensive.

Also, even when using the same basic clock signal,
In order to supply the basic clock signal to all the tone signal generating means and the tone signal mixing means, the basic clock signal line becomes very long, electromagnetic wave radiation increases, and other electronic devices may be damaged, and the load capacity and load may be reduced. There has been a problem that the basic clock signal is dull due to the resistance, causing a malfunction.

Further, in a plurality of electronic musical instruments, since the basic clock signal is generated separately, it is difficult to mix tone signals output from the plurality of electronic musical instruments as digital signals.
It was impossible. This is because even if a plurality of basic clock signals are nominally generated using the same frequency crystal oscillator, strictly speaking, the period of the basic clock signal is slightly different, and if this difference accumulates for the sampling period, the digital signal This is because a tone signal is dropped or duplicated, and noise is generated.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problem. By synchronizing a tone signal generating means and a tone signal mixing means operating with separate basic clock signals, the influence of a shift in the cycle of a plurality of basic clock signals can be obtained. It is an object of the present invention to provide a musical tone control device for an electronic musical instrument in which a plurality of musical tone signals can be mixed as digital signals.

Means for Solving the Problems In order to solve the above-mentioned problems, a musical sound control device for an electronic musical instrument according to the present invention comprises a plurality of basic clock generators for generating clocks that are not completely at the same frequency; Synchronizing signal generating means for generating a synchronizing signal for absorbing a difference in sampling frequency caused by a slight difference, and one or more tone signal generating means for synchronizing with the synchronizing signal and generating a tone signal in accordance with the basic clock Means,
One or more tone signal mixing means for mixing the tone signals in accordance with the basic clock in synchronization with the synchronization signal.

With the above configuration, the tone signal generating means and the tone signal mixing means operate in synchronization with the synchronizing signal of the synchronizing signal generating means for absorbing a difference in sampling frequency caused by a slight difference in the frequency of the basic clock. By doing so, the influence of the cycle of the basic clock signal slightly different between the synchronizing signal generating means, the tone signal generating means and the tone signal mixing means is eliminated, and the plurality of tone signals are mixed as digital signals without a cycle shift. It is also possible to include the basic clock generator in the tone signal generator or tone signal mixer.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a tone control device for an electronic musical instrument according to an embodiment of the present invention.

The musical tone control device for an electronic musical instrument according to the present invention comprises a synchronizing signal generating means 11 for generating a synchronizing signal S11, a synchronizing signal S11, and a digital tone signal S12 synchronized with the synchronizing signal S11.
And a synchronizing signal S11.
And a second tone signal generating means 13 having the same configuration as the first tone signal generating means 12 for generating a digital tone signal S13 in synchronization with the synchronizing signal S11.
And the digital tone signal S12 and the digital tone signal S13, and the digital tone signal S12 is synchronized with the synchronizing signal S11.
Signal mixing means 14 for mixing the digital tone mixing signal S1 and the digital tone mixing signal S1
4 is provided with a digital-analog converter (hereinafter referred to as DAC) 15 for performing digital-analog conversion, and a sound system 16 for inputting and outputting an output signal of the DAC 15.

The configuration and operation of the synchronization signal generating means 11
This will be described in detail with reference to the block diagram shown in the drawing and the time chart shown in FIG.

As shown in FIG. 2, the synchronizing signal generating means 11 includes a basic clock generating unit 21 for generating a basic clock signal S21, a counter 22 for dividing the frequency of the basic clock signal S21, and a value of the output Q of the counter 22 being "0". The output signal S23 becomes '1'
The detector 23, the '8' detector 24 in which the output signal S24 becomes '1' when the value of the output Q of the counter 22 is '8', and the output signal when the value of the output Q of the counter 22 is '16' S25 becomes '1', the '16' detector 25 resets the counter 22, the output signal S23 is set input, the output signal S24 is reset input, and the output Q
And an RS flip-flop (hereinafter abbreviated as RSFF) 26 that outputs a synchronization signal S11, and operates as follows.

The basic clock generator 21 generates a basic clock signal S21. The counter 22, which is a 5-bit binary counter with a clock synchronous reset input, receives the basic clock signal S2
Using 1 as a clock, count up from '0'. First, since the value of the counter 22 (the value of the output Q) is “0”, the output S23 of the “0” detector 23 becomes “1” and the RSFF 26
Of the synchronization signal S11 which is the output Q of the
Becomes '1'. When the value of the counter 22 becomes "8", the output S24 of the "8" detector 24 becomes "1" and the input R of the RSFF 26 becomes "1".
And the synchronization signal S11 becomes '0'. In addition, counter 2
When the value of 2 becomes '16', the output S25 of the '16' detector 25 becomes '1'
And the reset input RST of the counter 22 also becomes '1',
At the next rising edge of the clock, the value of the counter 22 is reset to “0”. Then, the synchronization signal S11 becomes “1” again.
In this manner, the synchronization signal S11 having one cycle of 17 basic clock signal cycles is generated.

Next, the configuration and operation of the tone signal generating means 12 and 13 will be described in detail with reference to the block diagram of FIG. 4 and the time charts of FIGS.

As shown in FIG. 4, the tone signal generating means 12, 13 includes a basic clock generator 31 for generating a basic clock signal S31.
And a counter 32 for dividing the basic clock signal S31, a D flip-flop (hereinafter abbreviated as DFF) 3 for inputting the synchronization signal S11 as data and the basic clock signal S31 as a clock input.
3, a DFF34 having a data input of the output signal S33 of the DFF33 and a clock input of the basic clock signal S31, and an output Q signal S3.
2-input AND gate that receives 3 and the output Q signal S34 of DFF34
35, counter 32 outputs QA ('1'), QB ('2'), QC
('4'), 4-input AND gate 38 for inputting QD ('8')
And the input signal S38 of the four-input AND gate 38
The output signal S35 of the input AND gate 35 is used as a reset input, the RSFF 36 resets the counter 32 with the output Q signal S36, the outputs QA, QB, QC, QD of the counter 32 and the basic clock signal S31.
And a tone signal synthesizing unit 38 that synthesizes and outputs the tone signal S12 or S13 as a timing signal,
It works as follows.

The basic clock generator 31 generates a basic clock signal S31. The counter 32, which is a 4-bit binary counter with a clock synchronous reset input, receives the basic clock signal S3
Using 1 as a clock, count up from '0'. When the outputs QA, QB, QC, and QD of the counter 32 all become "1", the output signal S38 of the 4-input AND gate 38 becomes "1", and RS
The set input S of the FF 36 also becomes "1", and the output signal S36 also becomes "1". Since the reset input RST of the counter 32 becomes '1', the value of the counter 32 is reset to '0' at the next rising edge of the clock, and the basic clock signal S31 enters while the reset input RST is '1'. Also, the value of the counter 32 remains '0'. If the value of the counter 32 does not advance, the tone synthesis in the tone signal synthesizing unit 37 does not proceed, and the state is stopped.

On the other hand, the synchronization signal S11 is
Sampled by F33 and 34. When the output Q signal S33 of DFF33 is '1' and the inverted output signal S34 of DFF34 is '1', the output signal S35 of the AND gate 35 becomes '1', and the synchronization signal S11 changes from '0' to '1'. Detect changes. AND gate 35
When the output signal S35 becomes "1", the reset input R of the RSFF 36 also becomes "1", the output Q signal S36 becomes "0", and the counter 32 resumes the counting operation from the next rising edge of the clock. Thus, the tone synthesis in the tone signal synthesizing section 37 is also restarted. Calculated tone signal S12 or S13
Is output when the value (QA, QB, QC, QD) of the counter 32 is “15”.

As described above, the generation of the tone signal S12 or S13 is performed in a cycle of 16 basic clock signals, and
Since 1 is a period corresponding to 17 basic clock signals, there is a stop state for a period corresponding to one basic clock signal as shown in FIG. Therefore, as shown in FIG. 7, when the cycle of the basic clock signal S31 of the tone signal generating means 12, 13 is shorter than the cycle of the basic clock signal S21 of the synchronizing signal generating means 11, the tone signal generating means 12, In 13, in addition to the stop state for a period of one basic clock signal S31, there may be a stop state for a period of two basic clock signals S31. This occurs when the cycle of the basic clock signal is accumulated for one cycle of the basic clock signal. vice versa,
If the cycle of the basic clock signal S31 of the tone signal generating means 12, 13 is longer than the cycle of the basic clock signal S21 of the synchronizing signal generating means 11, one basic clock signal S31 is generated in the tone signal generating means 12, 13. In addition to the stop state during the minute period, there is a case where the stop state does not occur, and thus the deviation of the cycle of the basic clock signal between the synchronizing signal generating means 11 and the tone signal generating means 12 and 13 is corrected.

Next, the configuration and operation of the tone signal mixing means 14 will be described in detail with reference to the block diagram of FIG. 8 and the time chart of FIG.

As shown in FIG. 8, the tone signal mixing means 14 includes a basic clock generator 41 for generating a basic clock signal S41, a counter 42 for dividing the frequency of the basic clock signal S41, and a synchronizing signal S41.
A D flip-flop (hereinafter abbreviated as DFF) 43 having 11 as a data input and a basic clock signal S41 as a clock input;
FF43 output Q signal S43 data input, basic clock signal S
DFF44 using 41 as a clock input, and output Q signals S43 and DFF4
A two-input AND gate 45 receiving the output signal S44 of FIG.
Output QA ('1'), QB ('2'), QC of counter 42
('4'), 4-input AND gate 52 for inputting QD ('8')
And the set input of the output signal S52 of the 4-input AND gate 52,
The output signal S45 of the input AND gate 45 is used as a reset input, the output Q signal S46 resets the counter 42 with the RSFF 46, and the output QD of the counter 42 is clock input, the digital tone signal
Multi-bit DFF47 with S12 as data input and counter
A multi-bit DFF 48 having a clock input of the output QD of 42 and a data input of the digital tone signal S13, an adder 49 for adding the output signal of the DFF 47 and the output signal of the DFF 48, and a counter 4
An inverter 50 for inverting the output QD of 2 and a DFF51 for inputting the output signal S49 of the adder 49 as a data input, using the output signal of the inverter 50 as a clock input, and outputting the output Q signal as a digital tone signal S14. It operates as follows.

A basic clock generator 41, a counter 42 which is a 4-bit binary counter with a clock synchronous reset input, and an output "1" when the value (QA, QB, QC, QD) of the counter 42 is "15". Input AND gate 52, DFFs 43 and 44 for detecting rising of synchronization signal S11, AND gate 45, and counter 42
The operation of the reset RSFF 46 is based on the tone signal generation means 12 and 13.
Since it is the same as the case of, it is omitted. The tone signals S12 and S13 output from the tone signal generating means 12 and 13 are
At the rising edge of the output QD 42, it is latched by the DFFs 47 and 48 and added by the adder 49. The result of the addition is latched by DFF51 when the output QD of the counter 42 falls, and is output as a tone mixing signal S14. In the tone signal mixing means 14 as well, the deviation of the cycle of the basic clock signal from the synchronization signal generation means 11 is corrected.

As described above, according to the present embodiment, the synchronization signal generating means 11
Music signal generating means 12, 1
By synchronizing the tone signal mixing means 14 with the tone signal mixing means 14, even if the tone signal generating means 12, 13 and the tone signal mixing means 14 operate with different basic clock signals, the shift of the cycle of the basic clock signal is corrected, The tone signals generated from the tone signal generating means 12 and 13 can be mixed as digital signals.

In this embodiment, the synchronizing signal generating means 11 is provided independently, but the synchronizing signal generating means 11 is
14, the synchronizing signal generating means 11 and the tone signal mixing means 14
May be operated with the same basic clock, and the synchronizing signal may be supplied to the remaining tone signal generating means 12 and 13. The flow of the synchronization signal in this case is shown in FIGS. 10 (a) and 10 (b). In FIG. 10, 'SG' indicates a tone signal generating means, and 'MIX' indicates a tone signal mixing means. Further, the synchronizing signal generating means may be included in the tone signal generating means. The flow of the synchronization signal in this case is as shown in FIG. Further, FIG. 10 (d)
Or the synchronization signals may be connected in a loop as shown in FIG.

Effects of the Invention As described above, according to the present invention, a plurality of basic clock generators that generate clocks that are not completely at the same frequency,
Synchronizing signal generating means for generating a synchronizing signal for absorbing a difference in sampling frequency caused by a slight difference in the frequency of the basic clock, and generating a tone signal in synchronization with the synchronizing signal and according to the basic clock Since at least one tone signal generating means and one or more tone signal mixing means for synchronizing with the synchronizing signal and mixing the tone signals in accordance with the basic clock are provided, a slight Therefore, it is possible to eliminate the deviation of the cycle of the basic clock signal which is different from the original one, and to mix the tone signal as a digital signal.

[Brief description of the drawings]

FIG. 1 is a block diagram of a tone control device for an electronic musical instrument according to one embodiment of the present invention, FIG. 2 is a block diagram of a synchronizing signal generating means of FIG. 1, and FIG. FIG. 4 is a block diagram of the tone signal generating means shown in FIG. 1, and FIGS.
FIG. 8 is a time chart of the tone signal generating means shown in FIG.
FIG. 9 is a block diagram of the tone signal mixing means shown in FIG. 9, FIG. 9 is a time chart of the tone signal mixing means of FIG. 8, and FIG. 10 is a connection diagram showing an example of connection of synchronization signals other than the present embodiment. 11 synchronization signal generating means, 12, 13 tone signal generating means, 14 tone signal mixing means, 15 digital-analog converter (DAC), 16 sound system, S11
Synchronous signal, S12, S13 ... Digital tone signal, S14 ... Digital tone mixed signal.

Claims (3)

(57) [Claims] 1. A plurality of basic clock generators for generating clocks not completely at the same frequency, and a synchronizing signal for absorbing a difference in sampling frequency caused by a slight difference in the frequency of the basic clock. Synchronizing signal generating means; one or more tone signal generating means synchronizing with the synchronizing signal and generating a tone signal in accordance with the basic clock; mixing the tone signal in synchronizing with the synchronizing signal and in accordance with the basic clock And a tone signal mixing means for an electronic musical instrument, comprising: at least one tone signal mixing means. 2. The tone control device for an electronic musical instrument according to claim 1, wherein said tone signal generating means includes a basic clock generator. 3. The tone control device for an electronic musical instrument according to claim 1, wherein the tone signal mixing means includes a basic clock generator.