JPH0623099U - Electronic sound generation circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] An inexpensive electronic configuration produces a sharp-rising electronic sound. [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. A bypass resistor R3 is provided in parallel with the CR time constant circuit 12, and when the pulse signal is generated, the transistor Q2 is driven without being affected by the charging waveform of the CR time constant circuit 12, so that only the resistor R3 is added to start up. You can make a sharp pronunciation.

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 with such a metal sounding body, a certain amount of lingering sound remains after being struck, and the sound is comfortable. 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, the electronic sound generating circuit using the CR time constant circuit requires a certain charging time to charge the CR time constant circuit, and the sound pressure gradually increases during the charging time. Therefore, there is a problem in that it is not possible to reproduce a sharp rising sound with the same feeling of impact as when hitting a metal sounding body. Although an electronic circuit can reproduce a sound with a sharp rising edge, the circuit tends to be complicated, which causes a problem that the price of the device rises.

[0005]

[Problems to be solved by the device]

 In view of such problems of the conventional technology, a main object of the present invention is to provide an electronic sound generation circuit which has an inexpensive circuit configuration and can generate an electronic sound having a sharp rising edge such as when a metal sounding body is hit. To provide.

[0006]

[Means for Solving the Problems]

 According to the present invention, such a purpose is to provide a pulse signal generating circuit capable of generating a pulse signal having a predetermined width, and a predetermined time from when the pulse signal is extinguished and when the pulse signal is extinguished. A CR time constant circuit configured to discharge with a constant, a sound frequency generating circuit for outputting a sound frequency signal for causing the sounding body to sound at a predetermined frequency, and A sounding body driving transistor for controlling the output signal of the sounding frequency generation circuit so as to change the sounding intensity of the sounding body, and the influence of charging of the CR time constant circuit when the pulse signal is generated. To provide an electronic sound generating circuit characterized by having a bypass resistor connected in parallel to the CR time constant circuit in order to drive the sounding body driving transistor without Ri is achieved.

[0007]

[Action]

 With this configuration, a pulse signal of a predetermined width can be input to the sounding body driving transistor through the bypass resistor from the time of its generation, and the rising time can be achieved without being affected by the charging characteristics of the CR time constant circuit. The sharp pronunciation of can be generated. After the pulse signal disappears, the sounding frequency signal can be attenuated according to the discharge characteristics of the CR time constant circuit, and a lingering electronic sound can be generated.

[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 1 is connected to the collector of the transistor Q1 in the forward direction toward the collector, and two resistors R1 and R2 of the CR time constant circuit 12 are connected between the diode D and the first driving transistor Q2. They are 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. There is.

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, at the same time when the transistor Q1 is turned on. 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 electronic sounds of 2 kHz and 1.6 kHz in accordance with the on-state decay 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 invention, since the drive signal from the transistor Q1 drives the first drive transistor Q2 through the bypass resistor R3 when it is generated, the first drive transistor Q2 immediately rises to the complete ON state. It is possible to generate a chime sound with the same impact as when hitting a metal sounding body.

[0017]

[Effect of device]

 As described above, according to the present invention, in a circuit for generating an electronic sound, a CR time constant circuit can be used to generate an electronic sound with a lingering sound, and a drive for generating the electronic sound. By bypassing the signal through the CR time constant circuit via the bypass resistor, the electronic sound can be immediately raised without being affected by the charging waveform of the CR time constant circuit. In this way, an inexpensive circuit with a simple circuit configuration of the CR time constant circuit and its bypass resistor can generate an electronic sound that has the same impact and reverberation as when a metal sounding body is struck. As a result, the marketability of electronic chimes 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 1st AND Circuit 11 2nd AND Circuit 12 At CR Constant circuit 13 Speaker R3 Bypass resistance

Claims (1)

[Scope of utility model registration request] 1. A pulse signal generating circuit capable of generating a pulse signal having 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. A sounding body driving transistor for controlling the output signal of the sounding frequency generating circuit;
An electronic sound generating circuit having a bypass resistor connected in parallel to the CR time constant circuit so as to drive the sounding body driving transistor without being affected by charging of the R time constant circuit.