JPH0623100U - Electronic sound generation circuit - Google Patents

Abstract

(57) [Summary] [Purpose] An inexpensive electronic circuit that produces an electronic sound with a good lingering finish. [Structure] The signal from the switch 1 is passed through a delay circuit 2 to generate a sounding interval oscillation circuit 3 and oscillating circuits 4 and 5 for high and low sounds.
To enter. The signal of the sounding interval oscillation circuit 3 is converted into a pulse signal of a predetermined width with a predetermined pitch through the one-shot circuits 7a and 7b and the OR circuit 8 to drive the transistor Q1. The transistor Q3 is turned on / off by alternating high and low frequency signals from the oscillation circuits 4 and 5, and
The speaker 13 driving transistor Q2 is driven by the output of the CR time constant circuit 12 that charges and discharges according to the pulse signal. By providing a reverberation generating resistor R4 in parallel with the transistor Q2 so that a predetermined drive current can flow through the speaker 13, and by driving the speaker 13 without being affected by the disappearance of the discharge waveform of the CR time constant circuit 12, Only by adding the resistor R4, it is possible to produce a sound with a proper lingering sound.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electronic sound generating circuit, and more particularly, to an electronic sound generating circuit that uses a CR time constant circuit to generate an attenuated sound.

[0002]

[Prior art]

 For example, some automobiles are provided with an alarm sound generation device for informing the driver by sound that a shift operation has been performed in the reverse position or the lamp is forgotten to be turned off. Some conventional alarm sound generators are designed to strike a metal sounding body, and such a metal sounding body has a certain lingering sound even after being struck and is pleasant to the touch. Can be pronounced.

In the above-mentioned alarm sound generating device, since the metal sounding body is hit to generate sound, there is a mechanically movable part, and there is a possibility that the cost of parts may increase in order to improve durability. there were. In order to eliminate the mechanical operation part, it is conceivable to configure an electronic sound generation circuit and generate an alarm sound by an electronic sound. By appropriately setting the vibration frequency of the sounding body, it is possible to use a conventional metal sounding body. You can easily reproduce the same high-pitched sound. With regard to the afterglow, for example, by using a CR time constant circuit, the afterglow can be formed by the attenuation characteristic of the CR time constant circuit at the time of discharge, and the sound can be attenuated with an inexpensive circuit configuration.

However, in an electronic sound generation circuit using a CR time constant circuit, if an attempt is made to give a residual sound time that remains to some extent as with a metal sounding body, only the residual sound time is changed only by changing the time constant. There was a problem that could not be changed. It is also conceivable to add a circuit that can be adjusted so as not to change the waveform of the part other than the afterglow time, but this causes a problem that the device price rises.

[0005]

SUMMARY OF THE INVENTION In view of the problems of the prior art as described above, the main object of the present invention is to provide an inexpensive circuit configuration and leave a proper finish as when a metal sounding body is hit. Another object of the present invention is to provide an electronic sound generation circuit capable of generating an electronic sound.

[0006]

[Means for Solving the Problems]

 According to the present invention, a pulse signal generating circuit capable of generating a pulse signal having a predetermined width and a pulse signal generating circuit that is charged during the generation of the pulse signal and is discharged at a predetermined time after the pulse signal is extinguished. A CR time constant circuit that discharges with a constant, a sound frequency generating circuit that outputs a sound frequency signal for causing the sounding body to sound at a predetermined frequency, and the above-mentioned according to the output waveform of the CR time constant circuit. A sounding body driving transistor for controlling the output signal of the sounding frequency generating circuit so as to change the sounding strength of the sounding body, and a predetermined strength regardless of the disappearance of the output waveform from the CR time constant circuit. To provide a drive current for the sound generator to the sound generator, and an electronic sound generation circuit having a reverberation generating resistor connected in parallel to the sound generator drive transistor. It is.

[0007]

[Action]

 In this way, the sounding body can generate sound according to a predetermined frequency by generating a pulse signal having a predetermined width. After the pulse signal disappears, the sound can be attenuated according to the discharge characteristics of the CR time constant circuit, and an electronic sound with a lingering sound can be generated, and the lingering sound connected in parallel to the sounding body driving transistor can be generated. The generation resistance makes it possible to continue a predetermined drive current to the sounding body drive transistor, and even if the CR time constant circuit is completely discharged, it is possible to continue sounding with a predetermined strength and leave a residual sound.

[0008]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an electronic sound generating circuit for generating an alarm sound when a reverse shift of a vehicle to which the present invention is applied is selected. In FIG. 1, the switch 1 is adapted to close in conjunction with a shift device (not shown) when the reverse position is selected. The signal from the switch 1 is input to the delay circuit 2, and the output signal from the delay circuit 2 is generated by the sounding interval oscillating circuit 3 as the pulse signal generating circuit, and the high-pitched sound oscillating circuit 4 and the low sound as the sounding frequency generating circuit. It is adapted to be input to the respective oscillation circuits 5 for. A reference clock oscillation circuit 6 for inputting each reference clock signal is connected to each circuit of the delay circuit 2, the sound generation interval oscillation circuit 3, the treble oscillation circuit 4, and the bass oscillation circuit 5. There is.

The output signal from the sounding interval oscillation circuit 4 is divided into two parts, one of which is input to the OR circuit 8 via the one-shot circuit 7 a, and the other is passed through the inverter circuit 9 and then the other one-shot circuit 7 b. It is adapted to be input to the OR circuit 8 via the. Further, one signal input from the sounding interval oscillation circuit 4 to the one-shot circuit 7a is also input to the first AND circuit 10, and the signal passed through the other inverter circuit 9 is also input to the second AND circuit 11. Has been The first AND circuit 10 receives the signal from the treble oscillation circuit 5, and the second AND circuit 11 receives the signal from the bass oscillation circuit 6.

The output signal from the OR circuit 8 is input to the base of the transistor Q1 for driving and controlling the CR time constant circuit 12. According to the output waveform of the CR time constant circuit 12, the first drive transistor Q2 as a sounding body driving transistor connected to the power source side of the speaker 13 as a sounding body is driven, and at the same time the both AND circuits 10 are connected. The second drive transistor Q3 connected to the ground side of the speaker 13 is driven according to the output waveform from 11. Therefore, the speaker 13 is driven when both drive transistors Q2 and Q3 are turned on.

The CR time constant circuit 12 is provided between the collector of the transistor Q1 whose emitter is grounded and the base of the first drive transistor Q2. A diode D is connected to the collector of the transistor Q1 in the forward direction toward the collector, and the two resistors R1 of the CR time constant circuit 12 are provided between the diode D and the first drive transistor Q2. -R2 is connected in series with each other. The capacitor C of the CR time constant circuit 12 is connected between the node between the resistors R1 and R2 and the power supply line. A bypass resistor R3 connected in parallel with the diode D and both resistors R1 and R2 is provided between the collector of the transistor Q1 and the base of the first drive transistor Q2 in order to bypass the diode D and the resistors R1 and R2. There is.

Further, between the emitter and collector of the first drive transistor Q2, a lingering character generating resistor R4 is connected in parallel with the first drive transistor Q2. A current supplied from the power supply line can flow to the afterglow generating resistor R4 when the second driving transistor Q3 is turned on. Therefore, regardless of the on state of the first driving transistor Q2, the speaker 13 is always in the sounding state. Can be The resistance value of the aftereffect resistance R4 is set to such an extent that a current that can be produced by the speaker 13 can flow at a sound pressure corresponding to an appropriate aftereffect.

The operation procedure of the electronic sound generating circuit thus configured will be described below with reference to the time chart of FIG. First, when the reverse shift position is selected and the switch 1 is closed, a delay signal is output from the delay circuit 2 after a predetermined delay time T1 (for example, 0.2 seconds) has elapsed from the signal input, and at that timing, A pulse wave of 1.8 Hz, for example, is output from the sounding interval oscillation circuit 3, an amplitude wave of, for example, 2 kHz is output from the high frequency oscillation circuit 4, and an amplitude wave of, for example, 1.6 kHz is output from the low tone oscillation circuit 5. To be done.

One of the pulse waves output from the sounding interval oscillation circuit 3 is directly input to the one-shot circuit 7 a, and the other is input to the one-shot circuit 7 b via the inverter circuit 9. The signal input from the circuits 7a and 7b to the OR circuit 8 is a pulse wave having a predetermined width that rises at the pitch T2 (approximately 0.55 seconds). Then, since the transistor Q1 is driven by the pulse wave having a predetermined width according to the pitch T2, the waveform at the point a in FIG. 1 which is the driving waveform thereof is predetermined at the pitch T2 as shown in FIG. Conduction is performed for a time T3 corresponding to the width.

Although the capacitor C of the CR time constant circuit 12 is charged during the conduction time T3, the first driving transistor Q2 is, as shown in FIG. 2, simultaneously with the on-state rush of the transistor Q1. Fully turned on. Since the transistor Q1 is turned off after the conduction time T3 has passed, the capacitor C starts to discharge, and the level of the first drive transistor Q2 in the on state is attenuated according to the time constant of the CR time constant circuit 12. Further, an oscillating wave of 2 kHz is constantly output from the oscillating circuit 4 for high-pitched sound, and an amplitude wave of 1.6 kHz is constantly output from the oscillating circuit for low-pitched sound 5, and each of them is passed through the second drive transistor Q3. The circuits 10 and 11 input the amplitude waveforms output from the sounding interval oscillation circuit 3 in which the phases of the amplitude waveforms are inverted, so that the amplitude waves of 2 kHz and 1.6 kHz are input to the second drive transistor Q3. They are inputting alternately at pitch T2.

Therefore, the speaker 13 produces the electronic sounds of 2 kHz and 1.6 kHz in accordance with the on-state attenuation waveform of the first drive transistor Q2. In this way, an electronic chime sound is obtained which alternately emits the electronic sounds of 2 kHz and 1.6 kHz which are attenuated at the pitch T2. Further, according to the present embodiment, since the drive signal from the transistor Q1 drives the first drive transistor Q2 through the bypass resistor R3 when the drive signal is generated, the first drive transistor Q2 rises to a complete ON state. It is possible to generate a chime sound with the same impact as when hitting a metal sounding body.

Further, the sound output of the speaker 13 is attenuated according to the discharge characteristic of the CR time constant circuit 12, but as described above, a predetermined current flows through the speaker 13 due to the afterglow generating resistor R4. Even after the circuit 12 is almost completely discharged, the speaker 13 continues to emit sound at the predetermined sound pressure level S as shown in FIG. By setting the sound pressure level S to be equal to the afterglow level when the metal sounding body is struck, it is possible to generate a chime sound having a suitable afterglow level similar to that of a metal chime.

[0019]

[Effect of device]

 As described above, according to the present invention, in a circuit for generating an electronic sound, when the electronic sound with a lingering sound is generated by using the CR time constant circuit, a sounding body is generated according to the waveform of the CR time constant circuit. Since the reverberation generating resistor is provided in parallel with the sounding body driving transistor for sounding, it is possible to continuously generate sound of a predetermined level without being affected by the discharge characteristic of the CR time constant circuit. Since it is possible to generate a chime sound that retains a suitable lingering level similar to that of a metal chime, the commerciality of the electronic chime can be greatly improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an electronic sound generating circuit for generating an alarm sound when a reverse shift of a vehicle to which the present invention is applied is selected.

FIG. 2 is a time chart showing an operating state of electronic sound according to the present invention.

[Explanation of symbols]

 1 Switch 2 Delay Circuit 3 Sounding Interval Oscillation Circuit 4 High-tone Oscillation Circuit 5 Low-tone Oscillation Circuit 6 Reference Clock Oscillation Circuit 7a ・ 7b One-shot Circuit 8 OR Circuit 9 Inverter Circuit 10 First AND Circuit 11 Second AND Circuit 12 At CR Constant circuit 13 Speaker R4 Reverberation generation resistor

Claims (1)

[Scope of utility model registration request] 1. A pulse signal generation circuit capable of generating a pulse signal of a predetermined width, and a CR which is charged during generation of the pulse signal and is discharged with a predetermined time constant after the pulse signal disappears. A time constant circuit, a sounding frequency generation circuit for outputting a sounding frequency signal for causing the sounding body to sound at a predetermined frequency, and a sounding strength of the sounding body is changed according to an output waveform of the CR time constant circuit. In order to flow a sounding body driving transistor for controlling the output signal of the sounding frequency generating circuit, and a driving current of a predetermined strength to the sounding body regardless of disappearance of the output waveform from the CR time constant circuit, An electronic sound generating circuit, comprising: a reverberation generating resistor connected in parallel to the sounding body driving transistor.