JPH0143760Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a chime sound signal generation circuit that generates a chime sound using an electronic circuit configuration, and particularly relates to an improvement of an envelope circuit that generates an attenuation waveform of a chime sound signal.

For example, a two-tone chime sound (a ping-pong sound) is often used as the ringing sound of an intercom or a so-called doorbell of a key telephone device, and the chime sound is a high-frequency, short-duration attenuated signal ( The sound caused by this signal is called a “pin tone.”)
and an attenuated signal having a low frequency and a long duration (the sound caused by this signal is called a "pop sound"), and its generating circuit is constructed as shown in FIG. 1, for example.

Figure 1 is a block diagram of the chime sound signal generation circuit, where A is the chime sound switching timing generation circuit, and B is the chime sound switching timing generation circuit.
is a chime sound oscillation circuit, C is an envelope circuit,
D is a modulation circuit.

Further, FIG. 2 shows the output signal waveforms of each block shown in FIG. 1.

Chime sound switching timing generation circuit A outputs a switching signal between "ping sound" and "pop sound" to chime sound oscillation circuit B, and also outputs a switching signal between chime sound oscillation circuit B and envelope circuit C.
outputs a signal that generates an envelope signal that forms a "ping" and "pop" sound.

Chime sound oscillator circuit B generates two types of single frequency signals (signals within the audible frequency range) corresponding to the "ping sound" and "pop sound" of the chime sound.

The envelope circuit C generates an envelope signal forming an attenuated waveform of the chime sound.

Modulation circuit D modulates the output signal of chime sound oscillation circuit B with an envelope signal (attenuated waveform) output from envelope circuit C, and sends a chime sound signal to output terminal T.

When a start circuit (not shown) instructs to send out a chime sound, the chime sound switching timing generating circuit A generates a signal at the level of the power supply voltage +V and a signal at the level of the ground potential, for example, as shown in a of FIG. (switching signal) is output alternately, and the switching signal is sent to chime sound oscillation circuit B and envelope circuit C. This switching signal is set so that the time it is at the power supply voltage +V level is shorter than the time it is at the ground potential level.

When chime sound oscillator circuit B receives the switching signal, as shown in FIG. ” is sent to the modulation circuit D.

In addition, the envelope circuit C has two circuits with different time constants.
When it receives the above switching signal, its power supply voltage +V as shown in Figure 2c.
At the level of , the charging circuit with the smaller time constant is charged and outputs an envelope signal that decays in a short time to the modulation circuit D, and the charging circuit with the larger time constant is charged at the ground potential level and decays in a long time. The envelope signal is output to modulation circuit D. In this way, envelope circuit C is chime sound oscillator circuit B.
The two envelope signals are switched and output alternately in synchronization with the switching of the frequency signal.

The modulation circuit D receives the frequency signal from the chime sound oscillation circuit B and the envelope signal from the envelope circuit C, and generates a high frequency signal (forming a "ping sound") that attenuates in a short period of time, as shown in FIG. signal) and a low frequency signal that decays over a long period of time (a signal forming a "pop" sound) are alternately sent to the output terminal T.

In the chime sound signal generation circuit described above, the charging circuit constituting the envelope circuit C is
Conventionally, for example, a circuit has been constructed as shown in FIG. Of the two charging circuits described above, FIG. 3 shows the charging circuit to which a signal at the ground potential level is input. Note that a charging circuit that is charged by inputting a signal at the level of the power supply voltage +V can be obtained by providing an inverting circuit at the front stage of the circuit shown in FIG.

In Figure 3, Q is a transistor for outputting the envelope signal, R and C are resistors and capacitors for setting time constants, D is a diode for discharging the charge in capacitor C, ST is a start terminal, and VT is a power supply. The terminal ET is the output terminal for the envelope signal.

When a signal at ground potential level is input to the start terminal ST, the connection between the start terminal ST (earth) - resistor R - capacitor C
- Transistor Q (base-emitter) - Power supply terminal
The charging current to capacitor C flows through the VT (+V) path. The charging current to capacitor C flows with an attenuation characteristic that is maximum at startup and gradually decreases, and transistor Q
If the bias is set optimally, an envelope signal conforming to the above-mentioned attenuation characteristic can be obtained at its collector.

However, as is well known, the current amplification factor of transistors, so-called H _FE , generally varies considerably depending on the individual transistors, and also changes significantly with changes in ambient temperature. Therefore, in order to obtain the output of the transistor Q at the maximum level, if the power supply voltage +V is set with the condition of maximum H _FE , then
If a transistor with a small H _FE is used as the transistor Q, or if the ambient temperature changes in a direction that lowers the H _FE , an envelope signal of a sufficient level cannot be obtained. Therefore, in the past, when the charging current to the capacitor C flows through the base of the transistor Q, the collector current of the transistor Q is biased (power supply voltage + V) so that the collector current of the transistor Q is saturated with the maximum value of the base current flowing through the transistor Q. is set to obtain an envelope signal that attenuates after reaching the power supply voltage +V. However, when set in this way, the envelope signal becomes a waveform in which the voltage at a constant level (power supply voltage + V) continues for a while and then attenuates, as shown in Figure 4. Moreover, the duration of the voltage at the constant level is longer than that of H _FE . It is not constant due to variations and changes, and the chiming sound obtained with such an envelope signal loses its timbre at the beginning (that is, in the part where the envelope does not attenuate), resulting in a sound that lacks clarity.

The present invention was made with the aim of eliminating these conventional drawbacks, and by providing an envelope circuit whose output voltage does not have a constant amplitude at the rising part of the chime sound, it is possible to produce a chime sound signal with a clear tone. The present invention provides a chime sound signal generation circuit that generates a chime sound signal.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 5 and 6.

FIG. 5 is a circuit diagram of an embodiment in which the present invention is implemented in the above-mentioned two-stroke chime sound signal generation circuit.
B, C and D are the same as each block shown in FIG. 1, and FIG. 6 shows the output waveforms of each part of the embodiment shown in FIG.

In the chime sound switching timing generation circuit A, S1 is a switch.

In chime sound oscillation circuit B, OSC1,
OSC2 is an oscillator that generates signals of different frequencies as the basic signal of the chime sound, and S2 is a switch.

Note that the switches S1 and S2 are shown conceptually in FIG. 5, and are normally configured as non-contact electronic circuits. Further, regarding the oscillators OSC1 and OSC2, the constant of the oscillation frequency determining element of one oscillator may be changed over by the switch S2.

In the envelope circuit C, C1 and C2 are capacitors (capacitive elements) that each generate envelope signals with separate curve characteristics when charged;
Q1 and Q2 are transistors (switch elements) that respectively control charging and discharging of capacitors C1 and C2 by conducting (hereinafter referred to as on) and non-conducting (hereinafter referred to as off), and D1 to D5 are transistors that control the charging and discharging of capacitors C1 and C2 respectively. Diodes R1 to R8 that prevent current from flowing to other circuits between the two charge/discharge circuits are resistors.

In the modulation circuit D, Q3 is a modulation transistor (intermittent switch element) that is intermittent based on a collector current based on an input signal to generate a chiming sound, and R9 to R11 are resistors.

Further, +V is a power supply voltage, and T is an output terminal of a chime sound signal. Above envelope circuit C
includes two circuits with mutually different envelope characteristics. That is, the first circuit includes transistor Q1,
Diodes D1 to D3, capacitor C1, resistor R
The above capacitor C1 is composed of R1 to R4 and R8.
The second circuit includes a transistor Q2, diodes D4 and D5, and a capacitor C.
2. A charging/discharging control circuit for the capacitor C2, which is composed of resistors R5 to R8. This first and second
The envelope characteristics of each of the circuits are, for the first circuit, when transistor Q1 is off,
It is determined by the time constant of the capacitor C1 and the resistor R4, and for the second circuit, when the transistor Q2 is off, it is determined by the time constant of the capacitor C2 and the resistor R7. Note that each of the first and second circuits is independently a chime sound signal generating circuit according to the present invention.

When the switch S1 of the chime sound switching timing generation circuit A is in the direction shown in the figure, and a signal with a voltage equal to the power supply voltage +V is output to its output, a base current flows through the resistor R1 to the transistor Q1, and the transistor Q1 Turns on. With transistor Q1 turned on, the following discharge path 1 is established for capacitor C1: capacitor C1 - diode D1 - transistor Q1 (collector - emitter) - ground - resistor R.
8-diode D3-capacitor C1...(1) are formed, and capacitor C1 is in a discharged state in preparation for a charging operation to capacitor C1, which will be described later.

By turning on the transistor Q1, the base potential of the transistor Q2 reaches the resistance R.
5 to the ground potential, and becomes an OFF state.

At this time, switch S of chime sound oscillation circuit B
2 is switched to the oscillator OSC1 side, and the above OSC
Every time the level of the output signal 1 (chime sound basic signal) reaches the ground level, the transistor Q3 of the modulation circuit D is turned off, and the next charging path 2 is connected to the capacitor C2: power supply (+V) - resistor R7 - capacitor C2. - Diode D5 - Resistor R11 - Ground (2) is formed, and each time the level of the output signal of the oscillator OSC1 becomes a positive level, the transistor Q3 is turned on, and the next charging path is established for the capacitor C2. 3. Power supply (+V) - resistor R7 - capacitor C2 - diode D5 - transistor Q3 (collector-emitter) - ground...(3) is formed. Therefore, the capacitor C2 is charged alternately by the charging paths 2 and 3, and the terminal voltage gradually increases according to the time constants of the charging paths 2 and 3, as shown in FIG. It continues to rise. However, since the resistor R11 of the modulation circuit D in the charging path 2 is set to a high resistance value, the progress of charging through the charging path 2 is extremely small, and the rise in the terminal voltage of the capacitor C2 during this period is due to charging. It is negligible compared to the increase in charging progress through path 3, and therefore the capacitor C
When transistor Q3 is turned on, the terminal voltage of No. 2 rises according to the time constant of charging path 3. When transistor Q3 is turned off, the voltage at the terminal immediately before turning off is maintained, and when transistor Q3 is turned on again, the voltage at the terminal immediately before turning off is maintained. The operation in which the voltage starts to rise again starting from the voltage at is repeated. In this way, the capacitor C is connected until the switch SI of the chime sound switching timing circuit A is switched to the ground side.
The rise in the terminal voltage of No. 2 progresses. From the above, it can be seen that the transistor Q3 acts to connect and disconnect the charging path 3 according to the frequency of the chime basic signal outputted from the oscillation circuit OSC1.

The output terminal T is connected to the collector of the transistor Q3 included in the charging path 3, and as shown in FIG. , a constant voltage applied to the charging path 3 each time it is turned off (in the case of the embodiment, the power supply voltage +
V) and the terminal voltage of capacitor C2 at that time v ₁ ,
A signal that rises to the level of the difference between v ₂ , v ₃ , etc. is obtained. As shown in FIG. 6, this signal has the frequency of the basic chime sound signal outputted by the oscillator OSC1, and is a signal that attenuates from the moment the transistor Q1 turns on and the transistor Q2 turns off. The “pin tone” of the chime sound of the sound structure
Configure.

Next, when the switch S1 of the chime sound switching timing circuit A switches in the direction opposite to that shown in the figure and outputs a signal at the ground potential, the base potential of the transistor Q1 becomes the ground potential and is turned off. When the transistor Q1 is turned off, a base current flows through the transistor Q2 through the resistors R3 and R5, and the transistor Q2 is turned on.
By turning on the transistor Q2, the following discharge path 4 is established for the capacitor C2: capacitor C2 - transistor Q2 (collector-emitter) - ground - resistor R8 - diode D
4-Capacitor C2...(4) is formed, and the charge of capacitor C2 charged in the above operation is discharged in preparation for the charging operation when the next "pin tone" is generated.

On the other hand, at this time, the switch S2 of the chime sound oscillator circuit B is also switched to the oscillator OSC2 side, and by turning off the transistor Q1, the output signal from the oscillator OSC2 of the chime sound oscillator circuit B (chime sound basic signal ), when transistor Q3 of modulation circuit D is off, capacitor C
1, the following charging path 5 is formed: power supply (+V) - resistor R4 - capacitor C1 - diode D2 - resistor R11 - ground (5), and when the transistor Q3 is on, the capacitor C1 On the other hand, the following charging path...6: power supply (+V) - resistor R4 - capacitor C1 - diode D2 - transistor Q3 (collector-emitter) - ground... (6) is formed. The charging paths 5 and 6 correspond to the charging paths 2 and 3 formed for the capacitor C2, respectively, and the operation that progressed when charging the capacitor C2 (the operation that forms a "pin tone")
An operation similar to that proceeds as the capacitor C1 is charged.

The time constant of the charging path 3 of the capacitor C1 and the time constant of the charging path (6) of the capacitor C2 are set so that the former is larger than the latter, and looking at the voltage change at both ends, the envelope due to the former is larger than the time constant of the charging path (6) of the capacitor C2. The attenuation is more gradual than that of the envelope.

The switch S2 of the chime sound oscillation circuit B is designed to be switched in synchronization with the switching of the switch S1 of the chime sound switching timing generation circuit A.
Therefore, switching of the charging circuit in the envelope circuit C and switching of the oscillation frequency in the chime sound oscillation circuit B (switching between the oscillators OSC1 and OSC2) are performed synchronously. Further, the oscillation frequency of the oscillator OSC1 is set higher than the oscillation frequency of the oscillator OSC2.

Therefore, when the switch S1 of the chime sound switching timing generation circuit A is switched to the ground side, the switch S2 of the chime sound oscillation circuit B as described above is also switched to the low frequency oscillator OSC2 side, and the transistor of the modulation circuit D is switched to the low frequency oscillator OSC2 side. Since the continuous operation of the charging path 6 by Q3 is based on the chime basic signal outputted by the oscillator OSC2, its intermittent frequency is lower than the intermittent frequency of the charging path 3 during the "ping tone" configuration operation.

As described above, from terminal T, the oscillator OSC
2 has the frequency of the chime basic signal outputted by the capacitor C from the moment the transistor Q1 is turned off according to the time constant of the charging path 6.
A damped vibration signal that gradually decreases by one terminal voltage v ₁ ′, v ₂ ′, v ₃ ′, .

Incidentally, the time constant of the discharging path (1) for the capacitor C1 is smaller than the time constant of the charging path 3 for the capacitor C2, and the time constant of the discharging path 4 for the capacitor C2 is smaller than the time constant of the charging path 6 for the capacitor C1. Capacitors C1, C2 and resistors R4,
Constants of R7 and R8 are set, and therefore, in the above operation, the electric charge charged in the capacitor C2 during the operation of forming the "ping sound" causes the "pop sound" to be generated during the operation of forming the "pop sound". The configuration of capacitor C during operation
The charge charged to 1 is completely discharged during the "pingyin" configuration operation. As a result, the envelope signal starts almost from the power supply voltage (+V), so the signal that makes up the "ping sound" or "pop sound" becomes a damped vibration signal whose initial level is extremely high, for example when hitting metal. You can get a chiming sound with a clear tone that closely resembles the vibration of the In addition, in Figure 6, oscillators OSC1 and OSC2 are shown for easy understanding.
Although the period of the output signal is expressed as extremely long, the period is actually much shorter than shown in the diagram, and therefore the initial peak value of the "ping sound" or "pop sound" is higher than shown in the diagram, and the period is actually much shorter than that shown in the diagram. Match or be very close.

As described above in detail with reference to the embodiments, according to the present invention, the change in the terminal voltage of the capacitor while the capacitor is being charged is directly used to form the envelope of the chime sound signal. It is impossible for the related transistors to be saturated by the envelope signal, and the chime sound signal has a waveform that continues to rise with a constant amplitude even if there are variations in the individual transistors or changes in ambient temperature. Therefore, a chime sound with a clear tone that decays naturally can be obtained, and the effect of the present invention is extremely large.

In addition, the type of frequency signal (chime sound basic signal) that constitutes the chime sound (i.e., the number of oscillators in the chime sound oscillation circuit or the number of frequency determining elements of the oscillator), its oscillation frequency, and the length of the envelope signal ( In other words, the relationship between the charging time constant of the charging path of the envelope circuit and the oscillation frequency is a design matter that can be set as appropriate when implementing the present invention, and these do not change the gist of the present invention.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a chime sound signal generation circuit, Figure 2 is an output waveform diagram of each block in the block diagram shown in Figure 1, Figure 3 is a circuit diagram showing a conventional example of an envelope circuit, and Figure 4. is an output waveform diagram obtained in the conventional example, and FIG. 5 is a circuit diagram of the embodiment of the present invention.
FIG. 6 is an output waveform diagram of each part of the circuit diagram shown in FIG. 5. A... Chime sound switching timing generation circuit, B
...Chime sound oscillation circuit, C...Envelope circuit, D...Modulation circuit, Q1, Q2...Transistor for charge/discharge control, Q3...Transistor for modulation,
C1, C2... Envelope signal generation capacitor, OSC1, OSC2... Oscillator, S1... Chime sound signal switching switch, S2... Frequency signal switching switch.

Claims (1)

[Scope of utility model registration request] Formed when the switch element Q1 or Q2 becomes conductive when the first switching timing signal is input and becomes non-conductive when the second switching timing signal is input, the capacitive element C1 or C2, and the switch element Q1 or Q2 become conductive. A discharge path of the capacitive element C1 or C2 formed when the switch element Q1 or Q2 is non-conductive, and a charging path of the capacitive element C1 or C2 formed when the switch element Q1 or Q2 is non-conductive, and a chime sound basic signal.
A switch element Q3 that is intermittent according to the frequency of the output signal of OSC1 or OSC2, and the switch element Q
A chime sound signal generation circuit consisting of a chime sound output terminal T connected to 3.