JPH0122629B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a sound source circuit for an electronic musical instrument that allows a desired combination of multiple foot temperaments to be easily obtained and is suitable for integration into an integrated circuit. In conventional electronic musical instrument sound source circuits, keyboard circuits that attempt to obtain multiple foot temperaments, such as 4', 8', and 16' at the same time, require complicated link wiring, and key switches also require multi-pole ones. However, the labor and cost required for production were extremely large.
Furthermore, since various tones are generally formed using only one type of waveform such as a symmetrical rectangular wave, the fidelity of string-based tones containing many harmonic components is unsatisfactory. For this reason, there are some that create a staircase wave to obtain a string-type tone, but they have the disadvantage that they require a resistor mixing circuit or the like, making the circuit configuration complicated. SUMMARY OF THE INVENTION An object of the present invention is to provide a sound source circuit for an electronic musical instrument that allows a desired combination of multiple foot temperaments to be easily obtained and is suitable for integration into an integrated circuit. In order to achieve the above object, the sound source circuit of the electronic musical instrument of the present invention includes a plurality of frequency dividing circuit groups that sequentially divide the highest frequencies of each of the 12 tone names (C to B) by 1/2,
A waveform forming circuit selectively derives waveforms having different duty ratios based on the output signals of the frequency dividing circuit group, and analog gate means deriving the output signals of the waveform forming circuit in response to keying signals generated by key presses. In the electronic musical instrument, between the frequency dividing circuit group and the waveform forming circuit,
A foot selection means is provided for controlling the number of frequency division stages of the frequency division circuit group and the frequency of the frequency division stages, and the foot selection means is used to combine the foot outputs of the respective output signals of the waveform forming circuit. It is characterized in that a plurality of combinations can be created and one or more of the combinations can be selected at the same time. The present invention will be described in detail below with reference to examples. FIG. 1 is an overall explanatory diagram of an electronic musical instrument including a tone generator circuit of the present invention. In the figure, a signal generated by a main oscillator 1 is frequency-divided by a frequency dividing circuit 2 to the highest frequency of each note name C to B, respectively. These signals with frequencies corresponding to each note name are then sent to the sound source circuit 3 corresponding to each note name.
Enter. As will be described later, the sound source circuit 3 includes a frequency dividing circuit group that sequentially divides the input signal by 1/2, a foot selection circuit that controls the number of division stages of the frequency dividing circuit group according to a preset foot selection signal, A waveform forming circuit that obtains three types of waveforms with different duty ratios from the output signal of the frequency dividing stage, a waveform selection circuit that selects and sets one waveform in advance from among the three types of waveforms with different duty ratios, and a waveform selection circuit that selects and sets one waveform in advance from the three types of waveforms with different duty ratios. It consists of an analog gate circuit that derives a signal selected by the circuit using a keying signal from the keyboard circuit 5 when a key is pressed. In other words, the sound source circuit 3 has two functions: ``a configuration for obtaining a combination of foot temperaments'', which is the essential part of the present invention, and a ``configuration for selecting waveforms with different duty ratios'', which is an essential part of the separately proposed invention. ing. Note that it is also possible to transform the keying signal generated by the key press into a signal having an arbitrary shape via the envelope circuit 4, if desired, and to control the analog gate circuit to obtain a sound signal according to the envelope. A sound signal derived from the sound source circuit 3 in response to a key depression is emitted via a mixing circuit 6, a tone color circuit 7, a tone color tablet switch 8, an amplifier circuit 9, and a speaker 10. FIG. 2 is a detailed explanatory diagram showing the configuration of an embodiment of the sound source circuit 3 of the present invention in FIG. 1. In the figure, the signal having the highest frequency of each tone name, for example, C note, from the frequency dividing circuit 2 is sent to the T flip-flop 31 ₁
The frequency is sequentially divided into 1/2 by a frequency dividing circuit group 31 consisting of _.about.318 . The number of division stages is controlled by a preset foot selection signal, and is controlled by a key switch.
By pressing keys K ₁ to _{K 5} , signals with frequencies shown in Table 1 are sent to the analog gates 35 (each gate 35 ₁
~35 ₅ ). Here, K ₁ to _{K 5} are key switches spanning five octaves corresponding to the C note, and f ₁ to _{f 9} are output frequencies from each stage when all of the frequency dividing circuit group 31 is operating.

[Table] As you can see from this table, the 2′, 4′,
For instruments that wish to simultaneously generate 8' sounds, use one with the foot selection terminal set to "01". In addition, foot rhythm 1′, 2′, 4′, 8′, 16′, 32′
If you want to obtain the following, you can use two types with the foot selection terminal set to "00" and "11". As described above, a desired combination of a plurality of foot rules can be easily obtained. Next, the output signal frequency-divided by the frequency dividing circuit group 31 is
In order to obtain waveforms having three different duty ratios, they are input to the waveform forming circuit 34 (each circuit 34 ₁ to 34 ₇ ). By providing these three types of waveforms as a selection signal to the waveform selection terminal in advance, one desired type of waveform can be obtained. A specific example of the waveform forming circuit 34 is shown in FIG. 3a. Frequencies F, 2F, which differ by an octave from the frequency dividing circuit group 31 are input to the three input terminals.
By inputting 4F, it is possible to output three types of waveforms with different duty ratios as shown in FIG. Of these three waveforms, only one waveform is selected by signals 1, 2, and 3 obtained by decoding the input signal from the waveform selection terminal by the decoder 33. For example, for a flute-type tone, the waveform selection terminal should be set to "00," and for a string-type tone, the waveform should be selected. Let's do it like this. In such cases, two integrated circuits (ICs) are used for each note, one for the flute and one for the string. It is obvious that if you do this, the string-type sounds will become more string-like. Also, when using one IC for one tone in a simple low-cost model, etc., the waveform selection terminal is selected in advance so as to obtain the waveform. Since there is a waveform selection terminal like this, 3
One type of IC can be commonly used for different types of waveforms without having to manufacture three types of ICs. The sound signal from the waveform forming circuit 34 (each circuit 34 ₁ to 34 ₇ ) is then sent to the analog gate circuit 35 (each circuit 35
₁ to 35 ₅ ), and the signal is passed by a keying signal by pressing a key. FIG. 4 shows an analog gate circuit 35 (35 ₁ to
A specific example of 35 ₅ ) is shown. As is clear from the figure, one keying signal, for example K ₁
As a result, the analog gate circuit ₃₅₁ is opened, and three types of foot rhythm signals are simultaneously output as shown in FIG. Therefore, instead of using three types of switches to output three types of foot-ratio signals as in the past, a single-pole switch is sufficient, and complicated external link wiring is not required. In the configuration shown in Fig. 2, from K ₁ to K ₅ , that is, from C ₁ to
A waveform of 5 octaves of _C5 is obtained. By the way, in a musical instrument with a 61-key keyboard, when 12 integrated circuits (ICs) shown in Fig. 2 are used for C to B, there is a shortage of one key. Therefore, the synchronization signal generation circuit 37 outputs the signal from the appropriate frequency division stage of the frequency division circuit group from the synchronization (SYN) terminal according to the waveform selection, and this terminal has the signals shown in FIG. Connect the accessory circuit shown in c. In other words, if the waveform selection in Fig. 2 is set in advance to the waveform shown in Fig. 3b, then the circuit shown in Fig. 5a is used, when the waveform is set, the circuit shown in Fig. 5b is used; The circuit shown in Figure c may be connected as an attached external circuit. Since this is not the main point of the invention, details will be omitted. In addition, the reset terminals in FIG. 2 and FIGS. 5 a to 5 c are connected to the frequency dividing circuit groups 31, 31 ₁ to
This is for resetting the ₃₁₈ , and is necessary to match the phase when two or more integrated circuits (ICs) are used for each sound, such as when using separate sound sources for string and flute sounds. FIG. 6 shows a specific example of the envelope circuit 4 shown in FIG. This is the key press signal KE ₁ from the keyboard circuit 5
A percussive effect and a sustain effect are applied to KE ₅ from the corresponding terminal, and keying signals K ₁ to _{K 5} with respective effects are sent to analog gates 35 and 35 ₁ to 3.
₅ to derive a desired sound signal. The differential output from the key press signal output terminal in the figure is used as a synchro start signal for an automatic accompaniment device. As explained above, according to the present invention, a foot selection circuit is provided for selecting a plurality of combinations from the output signals of the frequency dividing stage of the frequency dividing circuit group, and a desired combination of multiple foot rules is selected by an external terminal. Obtainable. In this case, the output signal of each stage of the frequency dividing circuit group is outputted from the gate circuit at the same time in response to key presses, so only one key switch is required, and therefore less wiring is required. . In the case of this embodiment, four types of foot rhythm combinations can be set in advance, so there is no need to manufacture four types of integrated circuits (ICs) each having a combination of foot rhythms, and one type can be used in common. . Further, as explained in the embodiment, a waveform forming circuit proposed by another applicant is provided in the output circuit of the foot selection circuit of the present invention, and various waveforms are configured and selected, thereby producing a desired tone. For example, it is possible to obtain a satisfactory waveform even for a string system. In the example, three types of waveforms are set, but in this case as well, when three types of waveforms are desired for one organ, there is no need to manufacture three types of integrated circuits, and one It can be made common by type. In this way, there is no need to manufacture multiple types of different integrated circuits in order to obtain combinations of different foot rhythms and different waveforms, and one type of integrated circuit can be used in common. Therefore, integrated circuits for sound source circuits are unified for all types of electronic musical instruments, from simple, low-priced models to complex, high-priced models, which greatly helps in reducing prices.

[Brief explanation of drawings]

FIG. 1 is an overall explanatory diagram of an electronic musical instrument including a tone generator circuit of the present invention, FIG. 2 is a detailed explanatory diagram showing the configuration of an embodiment of the tone generator circuit of the present invention, and FIGS. Specific examples of main circuits, FIGS. 5 and 6 are specific examples of related circuits in FIG.
2 is a frequency dividing circuit, 3 is a sound source circuit, 4 is an envelope circuit, 5 is a keyboard circuit, 6 is a mixing circuit, 7 is a tone circuit, 8 is a tone tablet switch, 9 is an amplifier circuit, 10 is a speaker, 31 is a divider Circuit group, 3
2 and 33 are decoders, 34 is a waveform forming circuit, and 35
Reference numeral 36 indicates an analog gate circuit, 36 a foot selection circuit, and 37 a synchronization signal generation circuit.

Claims (1)

[Claims] 1. A plurality of frequency dividing circuit groups that sequentially divide the highest frequencies of each of the 12 tone names (C to B) by 1/2, and the duty ratio is determined by the output signals of the frequency dividing circuit groups. An electronic musical instrument comprising a waveform forming circuit that selectively derives different waveforms, and an analog gate means that derives an output signal of the waveform forming circuit in response to a keying signal generated by pressing a key, wherein the frequency dividing circuit group and the waveform Between the formation circuit,
A foot selection means is provided for controlling the number of frequency division stages of the frequency division circuit group and the frequency of the frequency division stages, and the foot selection means is used to combine the foot outputs of the respective output signals of the waveform forming circuit. A sound source circuit for an electronic musical instrument, characterized in that a plurality of combinations are made and one or more of the combinations can be selected simultaneously.