JPS6140114B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electronic musical instrument, and more particularly to an improvement in an electronic musical instrument that generates tones of various tones depending on the setting state of a tone selection switch provided on a panel board of the electronic musical instrument. A timbre device that generates musical tones of various tones depending on the setting state of a timbre selection switch, for example, inputs a sound source signal having a frequency corresponding to the pitch of a key pressed on a keyboard section to a voltage-controlled filter;
There is a device that changes the characteristics (cutoff frequency and Q value) of this voltage-controlled filter as appropriate in accordance with the setting state of a timbre selection switch, thereby generating a musical tone signal imparted with a desired timbre. Therefore,
Naturally, in this type of timbre device, a control signal (a cut-off frequency control signal and a Q value control signal to be described later) corresponding to the timbre set by the timbre selection switch is supplied to the voltage-controlled filter. However, electronic musical instruments having tone devices of the type described above have the following drawbacks. That is, when all the timbre selection switches are in the OFF state, the control signal for changing the characteristics of the voltage-controlled filter described above becomes zero volts and is not output. Therefore, when the timbre selection switch is set to a certain timbre state from this state, a control signal having a desired voltage value is suddenly input to the voltage-controlled filter.
This causes a clicking sound when setting the tone. The present invention has been made in view of the drawbacks of conventional electronic musical instruments, and provides an electronic musical instrument that prevents click sounds from being generated when all tone color selection switches are set from an off state to a certain tone state. It is aimed at something. In the electronic musical instrument of the present invention, in addition to inputting a control signal corresponding to the setting state of the timbre selection switch to the circuit (voltage-controlled filter) that imparts timbre to the sound source signal, all timbre selection switches are also turned off. If it is set, the filter is configured to detect it and input a control signal corresponding to the predetermined tone color to the filter. Furthermore, the electronic musical instrument of the present invention is configured to detect when all of the tone color selection switches are set to the OFF state and to prohibit musical tone signals from being input to the sound system. Furthermore, the electronic musical instrument of the present invention is configured so that the amplitude of the musical tone signal is controlled in accordance with the setting state of the timbre selection switch so that a musical tone with a volume appropriate for the timbre set by the timbre selection switch is generated. There is. Furthermore, the electronic musical instrument of the present invention includes a plurality of voltage-controlled filters, and generates a plurality of sound source signals from each filter corresponding to the setting state of the timbre selection switch, and further selects an appropriate sound source from among the plurality of sound source signals. It is configured to select a signal and generate a musical tone using the selected signal as a musical tone signal. The present invention will be explained in more detail below with reference to embodiments shown in the accompanying drawings. FIG. 1 is a block diagram showing an example of an electronic musical instrument to which the present invention is applied. In FIG. 1, a keyboard circuit 1 detects a pressed key on the keyboard of an electronic musical instrument and outputs a key code KC corresponding to this key. This key code KC is input to the input terminal 11 of the sound source signal 2 as shown. The tone selection switch 7 is used to set the tone of the musical tone (piano tone, harpsichord tone, etc.) to be produced by this electronic musical instrument, and has a plurality of switches corresponding to various tones, and the settings of each switch The signal representing the parallel tone selection signal TCS
This is what is output as. This tone selection signal
The TCS is input to the parallel/serial converter 8 (hereinafter simply referred to as the P/S converter 8), where it is converted into a serial tone selection signal STCS, and then connected to the input terminal 12 of the sound source device 2 and the parallel/serial signal. The signal is input to the input side of the converter 9 (hereinafter simply referred to as the S/P converter 9). The sound source device 2 receives the key code KC and the serial tone selection signal STCS, and based on these, performs the pitch setting operation, waveform selection operation, octave switching operation, envelope adding operation, etc. of the sound source signal. Outputs two series of sound source signals SO1 and SO2, which have a pitch (frequency) corresponding to the key pressed in the timbre selection switch 7) and a waveform shape that basically corresponds to the timbre set by the timbre selection switch 7. These are output from terminals O1 and O2, respectively.
The sound source signal output from sound source signal 2 in this way
SO1 is input to the input side of voltage controlled filter 3 (hereinafter referred to as VCF3), and sound source signal SO2
is input to the input side of the voltage controlled filter 4 (hereinafter referred to as VCF4). As described above, the serial timbre selection signal STCS output from the P/S converter 8 is input to the input terminal 12 of the sound source signal 2 and is also input to the S/P converter 9. This S/P converter 9 receives the serial tone selection signal STCS, inversely converts it to the original parallel signal TCS, and outputs it.
This parallel timbre selection signal TCS is input to a VCF control signal generator 10, a select signal generator 11, and a level control signal generator 12, respectively. Furthermore, this S/P converter 9 has a function of detecting this state from the contents of the serial tone selection signal STCS when all the switches of the tone selection switch 7 are in the off state, and outputting an all-off detection signal AOF. ing. This all-off detection signal AOF is VCF
The signal is input to the control signal generator 10 and the level correction circuit 6, respectively. The VCF control signal generator 10 receives the parallel timbre selection signal TCS and outputs Q value control signals QS1 and QS2 for controlling the respective Q values of VCF3 and VCF4 from its output terminals O1 and O3, and further
Cutoff frequency control signals FS1 and FS2 that control the cutoff frequencies of VCF and VCF4, respectively
It has a function of outputting from its output terminals O2 and O4, respectively. Here, VCF3 and VCF4 each have three filter functions of a high-pass filter, a band-pass filter, and a low-pass filter, and the cut-off frequency control signals FS1, FS2 and Q value control signal
The filter characteristics of each of the above three filter functions are controlled by QS1 and QS2. In VCF3 and VCF4, the output corresponding to the high-pass filter function among the above three filter functions is output from the output terminal O1,
An output corresponding to the band pass filter function is output from the output terminal O2, and an output corresponding to the low pass filter function is output from the output terminal O3. Therefore, the frequency component (contained harmonics) of the sound source signal SO1 outputted from the output terminal O1 of the sound source signal 2 is controlled in VCF3 according to the cutoff frequency control signal FS1 and the Q-value electronic musical instrument QS1, and becomes a high-frequency sound source signal. After being converted into HSO1, band sound source signal BSO1 and low range sound source signal LSO1, each selection circuit 5
The signals are input to input terminals I1, I2, and I3 as shown in the figure. Similarly, the sound source signal SO2 output from the output terminal O2 of the sound source device 2 has a cutoff frequency control signal FS2 and a Q value control signal QS2 in the VCF4.
The frequency components (contained harmonics) are controlled according to the high frequency sound source signal HSO2 and the band sound source signal BSO2.
After being converted into the low-frequency sound source signal LSO2 and the low-frequency sound source signal LSO2, the signals are inputted to the input terminals I4, I5, and I6 of the selection circuit 5, respectively, as shown in the figure. An example of a voltage-controlled filter having three types of filter functions is the one disclosed in Japanese Utility Model Application No. 52-129228. Furthermore, all the tone selection switches 7 are set to the OFF state, and the S/P is set accordingly.
When the converter 9 outputs the all-off detection signal AOF, the VCF control signal generator 10 outputs the same cut-off frequency control signal as when one predetermined tone is set by the tone selection switch 7.
It is configured to output FS1, FS2 and Q value control signals QS1, QS2, respectively. Therefore, when all the timbre selection switches 7 are set to the OFF state, both VCF3 and VCF4 are the sound source signals HSO1, HSO1 and VCF4 corresponding to the above-mentioned one timbre.
Output BSO1, LSO1 and HSO2, BSO2, LSO2, respectively. The selection circuit 5 selects one signal from among the sound source signals HSO1, BSO1, and LSO1 input to the input terminals I1 to I3, respectively, and outputs the first signal from the output terminal O1.
output as musical tone signal MW1, and further input terminal I.
Sound source signals HSO input to each of 4 to I6
It has a function of selecting one signal from 2, BSO2, and LSO2 and outputting it from the output terminal 02 as the second sound source signal MW2. A selector signal SS output from a select signal generator 11 instructs the selection circuit 5 to perform a selection operation. The select signal generator 11 receives the parallel timbre selection signal TCS output from the S/P converter 9 and outputs a select signal SS corresponding thereto. Therefore, the selection circuit 5 selects the sound source signals (HSO1, BSO1, LSO1,
HSO2, BSO2, LSO2) are selectively output. In this way, the first musical tone signal MW1 selected from among the sound source signals HSO1, BSO1, and LSO1 and the second musical tone signal MW2 selected from among the sound source signals HSO2, BSO2, and LSO2 are connected to the resistors 51 and 5, respectively.
2, thereby synthesizing musical tone signals MW. The musical tone signal MW synthesized in this manner is input to the input terminal I1 of the level correction circuit 6. The level correction circuit 6 controls the amplitude of the musical tone signal MW input to the input terminal I1 in accordance with the level control signal LS input to the input terminal I2.
Here, the level control signal LS is output from the level control signal generator 12, and has a value corresponding to the parallel timbre selection signal TCS. As a result, the musical tone signal MW is given a volume suitable for the selected tone (piano tone, etc.). Note that if all the tone selection switches 7 are set to off,
The level correction circuit 6 is configured to inhibit the musical tone signal MW from being input to the sound system 13 in response to the all-off detection signal AOF output from the S/P converter 9. This prevents unnecessary noise from being generated when all of the tone color selection switches 7 are set to the OFF state. The musical tone signal MW, which has been given an appropriate volume in this manner, is input to a sound system 13 consisting of an amplifier, a speaker, etc., and is generated as a musical tone. In addition, in the embodiment described above, an example was explained in which two VCF3 and VCF4 were used as voltage-controlled filters, but the present invention is not limited to this, and it is possible to use three or more voltage-controlled filters. It's okay to have one. Furthermore, although VCF3 and VCF4 have been described as having three types of filter functions, it goes without saying that they may have two or four types of filter functions, or independent voltage control for each filter function. A type filter may also be used. FIG. 2 shows an example of the tone color selection switch 7 and P/S converter 8 shown in FIG. As shown in the figure, the tone selection switch 7 consists of seven switches S1.
-S7, and each of these switches S1-S7 is provided corresponding to each tone color as shown below. S1; Piano (signal PF) S2; Harpsichord (signal HC) C3; Jazz guitar (signal JG) S4; Electric guitar (signal EG) S5; Banjo (signal BJ) S6; Mandolin (signal MD) S7; Marimba (signal MR) Each of these switches S1 to S7 is configured to output a logical value "1" when set to ON, and the outputs of these switches S1 to S7 are converted into P/S as signals PF to MR as shown in the figure. The signal is input to the device 8. Here, these signals PE to MR constitute the timbre selection signal TCS described above. As shown in the figure, the P/S converter 8 includes seven stages 8-1 to 8-7, and is composed of a parallel input, serial output type shift register. still,
Although stages 8-3 to 8-6 are not shown in FIG. 2, each stage 8-1 to 8-7
have exactly the same configuration. Furthermore, the pulse signal SY input to the inverter 81 of the P/S converter 8 and the AND circuit A2 of each stage 8-1 to 8-7 is output at a constant cycle as shown in FIG. 3A. It is. Further, the clock pulses φ ₁ and φ ₂ inputted to the delay flip-flops FF of each stage 8-1 to 8-7 are pulse signals having phases different from each other by 180 degrees, as shown in FIGS. 3B and 3C. The delayed flip-flop FF is
A signal (logical value " ₁ " or "0") inputted to the input terminal D is taken in at the timing of the clock pulse φ1, and the received signal is outputted from the output terminal Q at the timing of the clock pulse _φ2 . Next, the operation of this P/S converter 8 will be explained. Depending on the setting state of the tone color selection switch 7, signals PF to MR are output from each switch S1 to S7 as the tone color selection signal TCS. These signals PF~
MR is the AND circuit A2 and OR circuit OR of each stage 8-1 to 8-7 at time t ₀ (timing when the pulse signal SY becomes logical value "1") shown in FIG.
1 to the delay flip-flop FF. At this time, each stage 8-1~
Since the AND circuit A1 of 8-7 receives a signal obtained by inverting the pulse signal SY shown in FIG. 3D by the inverter 81 (the logical value is "0" at time _t0 ), has no effect on this capture operation. In this way, the delay flip-flops of stages 8-1 to 8-7
Signals PF to MR taken into FF are time
It is output from its output terminal Q at the timing of clock pulse _φ2 at _t1 . At time _t1 , the pulse signal SY becomes the logical value "0", so the AND circuit A2 of each stage 8-1 to 8-7 is cut off, and from then on, the timbre selection signal TCS output from the timbre selection switch
(PF~MR) is blocked. On the contrary, since the inverted signal (logical value "1") of the pulse signal SY is input to the AND circuit A1 of each stage 8-1 to 8-7 via the inverter 81, each AND circuit A1 The signal input to the other input terminal (logical value "0" in stage 8-1, and the delay flip-flop FF of stages 8-1 to 8-6 in stages 8-2 to 8-7) content) will be output. That is, stage 8-1
Considering this, the logical value “0” input to the AND circuit A1 is the AND circuit A1, and the OR circuit
It is input to the input terminal D of the delay flip-flop FF via OR1, and taken in at the timing of clock pulse _φ1 at time _t1 . Other stage 8-2
Exactly the same operation is performed in stages 8-7 to 8-7, but in these stages 8-2 to 8-7, the contents recorded in the delay flip-flops FF of the preceding stages 8-1 to 8-6 are taken in. It can be done.
As is clear from the above explanation, the signal PF~ taken into each stage 8-1 to 8-7 at time _t0
MR is each shifted by one step to the right at time _t1 , and only the signal MR that has been taken into stage 8-7 is output (see FIG. 3E). Thereafter, exactly the same operation is performed from time _t2 to _t7 , and at each time from _t2 to _t7 , signals MD, BJ, EG, JG, HC, and PF are output as shown in FIG. 3E. Ru. Therefore, the tone selection signal TCS (PF
~MR) is output as a serial tone color selection signal STCS (PE~MR) at the timing shown in FIG. 3E. FIG. 4 shows an example of the S/P converter 9 shown in FIG. 1, and the serial timbre selection signal STCS (MR~
PF) is input to the input terminal D of the delay flip-flop 901. Further, the pulse signal SY shown in FIG. 3A is input to the input terminal D of the delay flip-flop 902. These delay flip-flops 901 and 902 each receive an input signal.
This is provided to output STCS and SY with a one-bit time delay. Therefore, the delay flip-flop 901 outputs the serial tone selection signal STCS' (a signal obtained by delaying the serial tone selection signal STCS by _{one bit} time) at the timing shown in FIG. 902 is a pulse signal at time _t1 as shown in FIG. 3G.
Outputs SY' (a signal obtained by delaying the pulse signal SY by 1 bit time). Delay flip-flop 902
The pulse signal SY' outputted by is inputted to a 7-stage, 1-bit system register 903 on one side. Here, the register 903 is driven by a clock pulse φ ₁ (FIG. 3B), and a logic value "1" is stored in its first stage at time t ₂ shown in FIG. From then on, each time t ₃
At ~ _t8 , the logical value "1" stored in the first stage is sequentially shifted to the second stage, third stage, and so on to the seventh stage, and along with this shift, the logical value "1" is output from the respective output terminals 01 to 07. 1” are output sequentially. That is, at time _t2 , a logical value "1" is output from output terminal 01, at time _t3 , a logical value "1" is output from output terminal 02, and in the same manner, at time _t8 , output terminal 0 is output.
7 outputs a logical value "1". In this way, the signals output from the respective output terminals 01 to 07 of the shift register 903 are outputted from the AND circuits 911 to 911, which operate at the timing of the clock pulse _φ2 (FIG. 3C).
917 to each input terminal I of the latch circuit 918.
1 to I7. The latch circuit 918 is configured to latch the signals input to the input terminals I1 to I7 only when a logic value "1" is input to the latch command signal input terminal L thereof.
Output terminals 01, 02,...07 of latch signal 918
The signals output from each are the aforementioned signals.
Parallel tone selection signal as MR, MD,...PE
Becomes TCS. Furthermore, the pulse signal SY' output from the delay flip-flop 902 is applied to the inverter 9 on the other hand.
04 to AND circuits 905 and 906 as a pulse signal' (H in FIG. 3). As is clear from FIG. 3H, at time _t1 , the pulse signal ' has a logic value of "0", so at this time both AND circuits 905 and 906 output a logic value of "0". This logical value “0” is applied to the input terminal D of the delay flip-flop 908 via the OR circuit 907.
The delay flip-flop 908 delays this input signal (logic value "0") by one bit time and outputs it from its output terminal Q at time _t2 .
Since this logical value "0" is input to the input side of the AND circuit 905, even if the pulse signal' has a logical value "1" from time t ₂ to t ₈ (see FIG. 3H), this Since the AND condition of the AND circuit 905 is not satisfied, this pulse signal of logical value "1"
A situation in which the contents of flip-flop 908 change from a logic value "0" to a logic value "1" due to SY' does not occur. This delay flip-flop 90
The logical value “0” outputted by the inverter 909
After the signal is inverted to a logic value "1" by , it is input to the first input terminal of the AND circuit 910. Therefore, after time _t2, the serial tone color selection signal STCS' input to the second input terminal of the AND circuit 910 is passed through the AND circuit 910 to the latch circuit 918.
It is input to the latch command signal input terminal L of. Therefore, at the timing when this serial tone color selection signal STCS' becomes the logical value "1", a 7-bit signal is output from each output terminal 01 to 07 of the shift register 903 (as described above, among these 7-bit signals) (only one signal of which has a logical value of "1") is latched by the latch circuit 918. 7 latched by the latch circuit 918 in this way.
The bit signal is output as a parallel timbre selection signal TCS. Next, the above operation will be explained in more detail.
Now, it is assumed that only switch S6 in the tone color selection switch 7 shown in FIG. 2 is set to be on, and only the signal MD is outputted as the tone color selection signal TCS with a logical value of "1". In this case, Figure 3 F
As is clear from the above, the delay flip-flop 901 outputs the logic value "1" at time _t3 , and this logic value "1" is outputted to the latch circuit 9 via the AND circuit 910.
It is input to the latch command signal input terminal L of 18.
Therefore, latch circuit 918 latches the 7-bit signal output from shift register 903 at time _t3 and outputs it as parallel timbre selection signal TCS. As mentioned above, at time _t3 , only the second stage of the shift register has the logical value "1".
is stored, and the logical value "1" stored in the second stage is inputted to the input terminal I2 of the latch circuit 918 via the AND circuit 915. Therefore, the latch circuit 918 outputs the timbre selection signal TCS in which only the signal MD is parallel to the logical value "1". Furthermore, when the serial timbre selection signal STCS' is first output as a signal with a logical value of "1" (this is realized at time _t3 in the above example), this logical value of "1" is output to the AND circuit 906 and the OR circuit. circuit 907
The signal is input to the input terminal D of the delay flip-flop 908 via. Therefore, the content of the delay flip-flop 908 changes from the logic value "0" to the logic value "1" after one bit time (in the above example, at time t _{4 )} .
(equivalent to), a logic value "1" is output from its output terminal Q. This logical value "1" is fed back to the delay flip-flop 908 via the AND circuit 905 and the OR circuit 907, which are enabled to operate by the pulse signal' (H in FIG. 3). is self-maintained at the logical value "1". The logic value "1" output from the delay flip-flop 908 is inverted to a logic value "0" by an inverter 909 and then input to an AND circuit 910. Therefore, the AND circuit 910 will operate from then on (corresponding to after time _t4 in the above example).
It functions to block even if the serial tone color selection signal STCS' has a logical value of "1". That is, when two or more switches (S1 to S7) are set to be turned on in the timbre selection switch 7, priority is set in the order of the switches S7 to S1, that is, in the order of the signals MR to PF. Only one tone is selected. Note that the logic value "1" stored and held in the delay flip-flop 908 is cleared when the pulse signal ' inputted to the AND circuit 905 becomes the logic value "0". As a result, the above-described operation is repeated again. Further, in the S/P converter 9 shown in FIG. 4, each output terminal 01 to 07 of the latch circuit 918 is connected to the input side of a NOR circuit 919, and furthermore, the output side of this NOR circuit 919 is connected to an OR circuit 920. is input to the input side of This part works as follows. That is, when the switches S1 to S7 of the timbre selection switch 7 are all set to the off state, the logic value "0" is naturally output from the output terminals 01 to 07 of the latch circuit 918. . In this case, the conditions of the NOR circuit 919 are satisfied, so the NOR circuit 919 outputs a logical value of "1".
This logical value “1” is sent as a signal via the OR circuit 920.
Output as JG. Therefore, in this case, it is assumed that the switch S3 in the timbre selection switch 7 has been turned on. In addition, in this case, the logic value "1" output from the NOR circuit 919 is the all-off detection signal AOF as shown in FIG.
It is input to a VCF control signal generator 10 and a level control signal generator 12. As described above, the parallel tone selection signal TCS (signal MR to signal
PF) is the VCF control signal generator 1 as shown in Figure 1.
0 and are input to the select signal generator 11 and level control signal generator 12, respectively. FIG. 5 shows an embodiment of the VCF control signal generator 10 shown in FIG. As mentioned above, this VCF control signal generator 10 generates tone selection signals output in parallel from the S/P converter 9.
Upon receiving TCS (signals MR~PF), this signal TCS
It outputs predetermined Q value control signals QS1 to QS2 and frequency control signals FS1 and FS2 according to the following. In the embodiment shown in FIG.
Predetermined field effect transistor T according to TCS
1, T27) becomes conductive, thereby 3
It is configured such that four voltage signals are output from the resistor ladder 101 configured in stages as Q value control signals QS1, TS2 and frequency control signals FG1, FS2, respectively. As mentioned above, in the tone selection switch 7 shown in FIG.
~If S7 is set to off, S/P
Signal JG from converter 9 as tone selection signal TCS
(logical value "1") is output, but in this case, the field effect transistors T10, T12, T13, and T14 are in a conductive state, similar to when the tone of the jazz guitar is selected by the tone selection switch 7. Q value control signals QS1, QS corresponding to the jazz guitar are generated through these field effect transistors.
2 and frequency control signals FS1 and FS2 are output. In the embodiment of the VCF control signal generator 10 shown in FIG. 5, the resistance ladder 101 is composed of three stages of resistance groups. This is resistance ladder 10
This is a measure designed to lower the output impedance of 1. The reason for this is that since the input impedance of VCF3 and VCF4 is usually high, noise is likely to occur when the output impedance of the resistor dollar 101 is high.
This is to start up FS2 quickly. FIG. 6 shows an example of the selection circuit 5, level correction circuit 6, selection signal generator 11, and level control signal generator 12 shown in FIG. As shown in the figure, the parallel timbre selection signal TCS (signal MR~
PF) are appropriately input to OR circuits 111 to 116 that constitute the select signal generator 11. The output side of these OR circuits 111 to 116 is connected to each field effect transistor T50 of the selection circuit 5.
1, T503, T505, T507, T509,
It is input to the gate terminal of T511. These field effect transistors T501, T503,
The first terminal (drain side) of T505 receives the high frequency sound source signal output from VCF3 as shown in Figure 1.
HSO1, band sound source signal BSO1, low range sound source signal LS
01 are respectively input, and similarly field effect transistors T507, T509, T51
Field effect transistors T501, T503, and T50 are inputted to the first terminals of VCF4, respectively, with a high frequency sound source signal HSO2, a band sound source signal BSO2, and a low frequency sound source signal LSO2 output from the VCF4.
The second terminal (source side) of T5 is connected to one end of a resistor 51, and is sometimes connected to a field effect transistor T50.
7, the second terminal of T509, T511 is resistor 52
The other ends of both resistors 51 and 52 are connected together. Further, the output side of each OR circuit 111 to 116 is connected to an inverter 50 on the other side as shown in the figure.
Field effect transistor T5 via 1 to 506
02, T504, T506, T508, T51
0, connected to the gate terminal of T512. These field effect transistors T502, T504,
The first terminals of T508, T510, and T512 are field effect transistors T501 and T50, respectively.
3. Connected to the first terminals of T505, T507, T509, T511, field effect transistors T502, T504, T508, T510, T5
The twelve second terminals are connected to the power supply -V/2 via resistors R51 to R56, respectively. Next, as an example, the select signal generator 11
The operation of the selection circuit 5 will now be explained. Now signal JG (Jaz guitar sound) as tone selection signal TCS
is input as a logic value "1", the logic value "1" is input only to the OR circuits 113 and 116, and the gate terminals of the field effect transistors T505 and T511 are connected via these to the OR circuits 113 and 116. A logical value “1” is input to Therefore, in this case, field effect transistors T505 and T51
1 becomes conductive, which causes the low-frequency sound source signal
LSO1 and LSO2 are selected by selection circuit 5 and mixed via resistors 51 and 52.
Also, at this time, OR circuits 111, 112, 11
4 and 115 output a logical value "0", these logical values "0" are outputted to the inverters 501 and 115, respectively.
Field effect transistors T502, T inverted to logical value “1” by 502, 504, 505
It is input to the gate terminals of 504, T508, and T510. Therefore, these field effect transistors T502, T504, T508, and T510 become conductive, respectively, thereby causing field effect transistors T501, T503, T507, and T510 to become conductive.
The first terminals of 509 are resistors R51 and R5, respectively.
2, is fixed to the power supply -V/2 via R54 and R55. As is clear from the above explanation, the select signal generator 11 outputs the logic value "1" from the OR circuits 111 to 116 as appropriate in accordance with the tone selection signal TCS,
As a result, the field effect transistor T501,
T503, T505, T507, T509, T5
11 is appropriately selected and becomes conductive. As a result, the sound source signals HSO1, BSO1, LSO1 and the sound source signals HSO2, BSO2, LSO2 are appropriately selected and output as musical tone signals MW1, MW2, respectively. These musical tone signals MW1 and MW2 have a low resistance of 51,5
2 is input to the level correction circuit 6 as a synthesized aftertone signal MW. In this embodiment, the sound source signals (HSO1 to LSO1, HSO
2~LSO2) is shown in the following table.

[Table] If all switches S1 to S7 in the tone selection switch 7 shown in FIG. 1 (and FIG. 2) are set to the off state, the signal JG is used as the tone selection signal TCS as described above. becomes the logical value “1”. Therefore, in this case, the sound source signals LS1 and LSO2 are selectively output as in the case where the jazz guitar sound is selected. The musical tone signal MW formed in the above manner is the sixth
As shown in the figure, the signal is input to the first terminal of the field effect transistor T601 of the level correction circuit 6. As mentioned above, this level correction circuit 6 receives the tone selection signal.
This is a circuit that gives appropriate volume to musical tones according to TCS. Field effect transistor T601
The gate terminal of S/
All-off detection signal output from P converter 9
AOF (see Figure 4) is input, and the first terminal of this all-off detection signal AOF is connected to the second terminal of the field effect transistor T601, and the second terminal is connected to the power supply -V. /2 is input to the gate terminal of the field effect transistor T602. In addition, resistors R61 and R6 are connected to the second terminal of the field effect transistor T601.
2, R63, and R64 are connected in series, and field effect transistors T603, T604, T605, and T605, respectively, are connected between each resistor as shown in the figure.
The first terminal of T606 is connected. The second terminals of these field effect transistors T603 to T606 are connected in common to the power supply -V/2. Furthermore, the second terminal of the field effect transistor 601 is connected to the input side of the sound system 13 shown in FIG. Further, as shown in FIG. 6, the timbre selection signal TCS output from the S/P converter 9 is input to the selector signal generator 11 as described above, and is also input to the level control signal generator 12. . The level control signal generator 12 has an OR circuit 121,
Signals MR, MD, and EG of the timbre selection signal TCS are input to this OR circuit 121. The output side of this OR circuit 121 is connected to the gate terminal of the field effect transistor T605 of the level correction circuit 6. In addition, the tone selection signal
Signal PF of TCS is input to the gate terminal of field effect transistor T603 of the level correction circuit 6, signal JG is similarly input to the gate terminal of field effect transistor T604, and signal BJ is input to the gate terminal of field effect transistor T604. It is input to the gate terminal of type transistor T606. Next, the operation of the level control signal generator 12 and level correction circuit 6 having the above configuration will be explained. Now, the switch S1 is set to be on in the timbre selection switch 7 shown in FIG. 2, and the signal PF (logical value "1") is outputted from the S/P converter 9 as the corresponding timbre selection signal TCS. It is assumed that there is At this time, the S/P converter 9 outputs the logic value "0" as the all-off detection signal AOF since the switch S1 is set to be on. After this logical value "0" is inverted to a logical value "1" by the inverter 601, it is input to the gate terminal of the field effect transistor T601. Therefore, the field effect transistor T601 becomes conductive, thereby allowing the musical tone signal MW to pass through. Also, all-off detection signal
Since the AOF has a logical value of "0", the field effect transistor T602 is in a cutoff state and has no effect on the level correction operation. Furthermore, the signal PF becomes the logical value "1" and the level correction circuit 6
Since the input is to the gate terminal of the field effect transistor T603, the field effect transistor T6
The second terminal of 01 is connected to the potential - through the resistor R61.
V/2 is applied. Therefore, in this case, the second terminal of the field effect transistor T601 is lowered by the potential -V/2 only through R61, and the level of the musical tone signal MW is corrected. Similarly, when switch S3 is turned on in timbre selection switch 7 and signal JG (logic value "1") is output as timbre selection signal TCS, field effect transistor T604 of level correction circuit 6 is turned on. state, resistors R61 and R62
A potential -V/2 is applied to the second terminal of the field-effect transistor 601 via the terminal 601, thereby correcting the level of the musical tone signal MW. Further, when the switch S5 in the timbre selection switch 7 is turned on and the signal BJ (logic value "1") is output as the timbre selection signal TCS, the field effect transistor T606 becomes conductive. Resistance R
A potential -V/2 is applied to the second terminal of the field effect transistor T601 via R61 to R64, thereby correcting the level of the musical tone signal MW. Furthermore, in the tone selection switch 7, the switch S
If any of 4, S6, and S7 is set to be turned on, the signal EG,
One of MD and MR is logical value “1”
becomes. Therefore, in this case, a logical value "1" is input to the gate terminal of the field effect transistor T605 via the OR circuit 121, the transistor T605 becomes conductive, and the potential -M/2 is applied to the resistor R6 1, It is applied to the second terminal of the field effect transistor T601 via R62 and R63, thereby correcting the level of the musical tone signal MW. In addition, in the tone selection switch 7, switch S2
is set and the tone selection signal TCS is used as the signal HC.
(logical value "1"), the level control signal generator 12 and level correction circuit 6 do not function at all, and in this case, the musical tone signal MW is directly passed through the field effect transistor T601. It is input to the sound system 13. Also, in the tone selection switch 7, the switch S
1 to S7 are all set to the off state, the S/P converter 9 shown in FIG. 4 outputs the all-off detection signal AOF as a logical value "1" as described above. In this case, the field effect transistor T601 is in the cutoff state and the field effect transistor T602 is in the conduction state.
The second terminal of the field effect transistor T601 is fixed at a potential of -V/2. Therefore, since the musical tone signal MW is blocked, no musical tone is generated. In this way, the musical tone signal MW to which the volume corresponding to each tone is given in the level correction circuit 6 is the first
As shown in the figure, the signal is input to the sound system 13 and generated as a musical tone. As is clear from the above description, the present invention provides the following effects. (b) Even if all the tone selection switches are set to the OFF state, the configuration is configured so that this is detected and a voltage signal of an appropriate value is input to the voltage control type filter, so tone selection can be performed from this state. Even if the switch is set to a certain tone, this will not cause a clicking sound. (b) If all tone selection switches are set to the off state, the system is configured to detect this and prohibit musical tone signals from being input to the sound system, so noise may not be generated. do not have. (c) Since the volume of the musical tone signal is adjusted according to the setting state of the tone selection switch, it is possible to generate a musical tone having an appropriate volume for each tone. (d) Since the VCF control signal generator is configured using a multi-stage resistor ladder, the rise of the Q value control signal and cutoff frequency control signal can be made faster, and it can also be used with a voltage controlled filter with high input impedance. Can be easily connected.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of an electronic musical instrument to which the present invention is applied, Fig. 2 is a circuit diagram showing an embodiment of the tone selection switch and P/S converter shown in Fig. 1, and Figs. H is a timing chart for explaining the operation of the embodiment of this invention, and FIG.
A circuit diagram showing an embodiment of the S/P converter shown in the figure,
FIG. 5 is a circuit diagram showing an embodiment of the VCF control signal generator shown in FIG. 1, and FIG. 6 is a circuit diagram showing the selection circuit, level correction circuit, select signal generator, and level control signal generator shown in FIG. 1. FIG. 2 is a circuit diagram showing an embodiment of the present invention. 1... Keyboard circuit, 2... Sound source signal, 3, 4...
Voltage control filter (VCF), 5...Selection circuit, 6
...Level correction circuit, 7...Tone selection switch,
8...P/S converter, 9...S/P converter, 10
...VCF control signal generator, 11...Select signal generator, 12...Level control signal generator.

Claims (1)

[Claims] 1. A first circuit that generates a control signal corresponding to the tone set by the tone selection switch; The tonal characteristics are changed accordingly,
As a result, a second circuit that imparts the timbre set by the timbre selection switch to the sound source signal, and a second circuit that detects when all the timbre selection switches are set to the OFF state and outputs a detection signal. and a fourth circuit that receives the detection signal and generates the same control signal as when a certain predetermined tone is set from the first circuit and inputs it to the second circuit. , an electronic musical instrument including. 2. The second circuit comprises a voltage-controlled filter, and the first circuit generates a control signal with a voltage value corresponding to the tone set by the tone selection switch. The electronic musical instrument according to item 1. 3. The electronic musical instrument according to claim 1, wherein the first circuit is constituted by a multi-stage resistance ladder circuit. 4. A first circuit that generates a control signal corresponding to the timbre set by the timbre selection switch, and a circuit that receives the sound source signal corresponding to the pressed key and the control signal, and changes the timbre characteristics in accordance with the control signal. is,
As a result, a second circuit that imparts the timbre set by the timbre selection switch to the sound source signal, and a second circuit that detects when all the timbre selection switches are set to the OFF state and outputs a detection signal. and a fourth circuit that receives the detection signal and generates the same control signal as when a certain predetermined tone is set from the first circuit and inputs it to the second circuit. and a fifth circuit that receives the detection signal and prohibits the signal output from the second circuit from being input to the Sando system. 5. A first circuit that generates a timbre selection signal corresponding to the setting state of the timbre selection switch; a second circuit that receives the timbre selection signal and generates a corresponding timbre control signal; and a second circuit that corresponds to the pressed key. a third circuit that receives the sound source signal and the timbre control signal, changes the timbre characteristic in accordance with the control signal, and thereby imparts the timbre set by the timbre selection switch to the sound source signal; a fourth circuit that detects when all the tone selection switches are set to the off state and outputs a detection signal; and a fourth circuit that detects this and outputs a detection signal, and a predetermined tone that is set by the first circuit in response to the detection signal. a fifth circuit which generates the same tone control signal as in the case of
a sixth circuit that receives the timbre selection signal and generates a level control signal for controlling the amplitude of the musical tone signal in accordance with the timbre set by the timbre selection switch; and the level control circuit. An electronic musical instrument comprising: a seventh circuit that receives the signal and controls the amplitude of the musical tone signal accordingly. 6. A first circuit that generates a timbre selection signal corresponding to the setting state of the timbre selection switch; a second circuit that receives the timbre selection signal and generates a corresponding voltage signal for timbre control; and a pressed key. receiving the sound source signal corresponding to the voltage signal and the voltage signal, changing the filter characteristics according to the voltage signal, and thereby outputting a plurality of sound source signals each having a tone set by the tone selection switch. two voltage-controlled filters; a third circuit that detects when all of the tone selection switches are set to the OFF state and outputs a detection signal; and a third circuit that receives the detection signal and outputs a detection signal; a fourth circuit that generates the same voltage signal as when a certain predetermined tone is set from the circuit and inputs it to the voltage-controlled filter; and a fourth circuit that receives the tone selection signal and operates the at least two voltage-controlled filters. a fifth circuit that generates a selector signal for selecting an appropriate sound source signal from among the plurality of sound source signals respectively output by the at least two voltage-controlled filters that receive the select signal and output each of the at least two voltage-controlled filters; An electronic musical instrument comprising: a sixth circuit that selects an appropriate sound source signal from among a plurality of sound source signals and outputs it as a musical tone signal.