JPH01246949A - Call circuit for interphone - Google Patents

Abstract

PURPOSE:To enable sending chime sounds having an excellent acoustic feeling by attenuating the chime sounds composed of 1st and 2nd sounds by means of a digital variable resistor. CONSTITUTION:When a call button switch(SW) is depressed, a signal is sent to the input port 03 of a microcomputer 10. By receiving the signal, the control port 04 of the computer 10 becomes active and supplies power to an amplifier 15. Simultaneously, a chime sound producing program is executed and chime sounds of 650Hz and 512Hz are successively sent to a digital variable resistor 11 where both chime sounds are attenuated in accordance with a preset order. The attenuated chime sounds are outputted from a loudspeaker 16. The resistance values of the resistances 11a-11d of the resistor 11 successively increases from the resistance 11a having the lowest value to the 11d having the highest value.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an intercom calling circuit, and more particularly to an intercom calling circuit that outputs a chime sound composed of electronic sounds. [Prior Art] Conventionally, an intercom has been used. It is known that the ringing circuit uses a chime sound generated by a chime sound generating circuit shown in FIG. 4 (Japanese Patent Publication No. 49359/1983) as a ringing sound.

The chime sound generation circuit shown in Figure 4 consists of a basic oscillation circuit 1, a monostable multivibrator circuit 2, and a monostable multivibrator circuit 2, which generates a pseudo chime sound.
It consists of a JJ decay circuit 3 and a power supply time limit circuit 4.

When the calling start switch S is operated, the power supply time limit circuit 4 is started and the chime sound transmission time is determined. When the power supply time limit circuit 4 is activated, power is supplied to the basic oscillation circuit 1, the monostable multivibrator circuit 2, and the amplifier A, which generate a pseudo chime sound. Therefore, the on/off operation of transistors Q2 and Q is determined by the time constant including capacitor C6 of monostable multivibrator circuit 2, and a bias circuit of diodes D6 and D6 is formed or cut off to form an oscillation constant. Short-circuit or open the resistor R, and switch the oscillation frequency from the first sound to the second sound. The two oscillation frequencies undergo a predetermined attenuation in the attenuation circuit 3, and a chime sound is transmitted from the speaker SP.

In addition, the symbol R8 (n is 1 to 23) in the figure is a resistor, CPt (
n is 1 to 6) is a capacitor, Q and l (n is 1 to 6) are transistors, and D and + (n is 1 to 9) are diodes.

[Problems to be Solved by the Invention] Since the chime sound generating circuit in the above embodiment performs the oscillation and organization of the first and second sounds in an analog manner using wiring logic, it is possible to eliminate the influence of variations in the characteristics of circuit elements. There are problems that need to be solved, such as being easily damaged, requiring a large number of parts, and not being able to produce a stable chime sound.

[Object of the Invention] The present invention has been made in view of the above-mentioned points.
To provide a calling circuit for an intercom capable of transmitting a chime sound with excellent pitch by attenuating the chime sound consisting of a sound with a digital variable resistor.

[Means for Solving the Problems] A calling circuit for an intercom according to the present invention includes a calling button, a chime sound sending means for sending a chime sound according to a preset order in response to the operation of the call button, and a digital variable resistor that attenuates the chime sound sent from the chime sound sending means by changing the resistance value according to the order;

and a speaker that outputs a chime sound that is attenuated by the digital variable resistor.

[Embodiments of the Invention] Hereinafter, an embodiment of a calling circuit for an intercom according to the present invention will be described in detail with reference to the drawings.

In FIG. 1, 10 is a microcomputer. When the microcomputer 10 operates the call button SW, a signal is input to the input port 03 and the control starts. The microcomputer 1o incorporates a chime sound sending program 25 shown in FIG. 2 as a chime sound sending means. When the call button SW is operated, the chime/sound sending program 25 is executed, and in process 26, the chime/sound sending program 25 is executed, and the sound 65 corresponding to the first sound is executed.
The chime sound of 0Hz is controlled by the control terminal L7 (n is 1, 2, 4...
8). 650Hz chime sound is 0-750
Until m5, the digital variable resistor 11 is controlled by the first attenuation control subroutine 28 according to a preset order. Judgment box 27 whether 750m5 has passed or not
When 750 m5 has elapsed, a chime sound of 512 Hz corresponding to the second sound is sent to the control terminal L71 (n is 1.2.4.8) in step 29. At the same time, the second attenuation control subroutine 31 controls the digital variable resistor 11 according to a preset order. In the digital variable resistor 11, resistors 11a, llb, llc, and lid are connected to control terminals L1, L2, L4, and L8 of the microcomputer 10.
The resistor 12 is connected to the power supply side, and the resistor 13 is connected to the reference potential side. Resistor 11a, llb, llc, lid
, 12 and 13 are connected to the input side of the amplifier 15 via a capacitor 19. Power is supplied to the amplifier 15 via the emitter and collector by turning the transistor 14 on and off. Further, the transistor 14 is controlled from the control port 04 of the microcomputer 10. In the figure, reference numeral 01.02 is a power supply terminal, Xl and x2 are clock terminals, 20.21 is a capacitor, 22 is an oscillator, and 23 is a Zener diode.

[Operation of the invention] When the call button SW is pressed in the intercom call circuit having the above configuration, the input port 03 of the microcomputer 10 is pressed.
A signal is sent to. This makes the control port 04 active and supplies power to the amplifier 15. At the same time, the chime sound sending program 25 is executed, and a chime sound of 650 Hz is sent to the digital variable resistor 11.
A 2 Hz chime sound is sent to the digital variable resistor 11. Note that among the resistors 11a to lid, the resistor 11a is the lowest, the resistor 11b and the resistor Lie increase in order, and the resistor lid is the highest. As shown in Figure 3, the transmission time of the first sound τ□ is 750m5, and the transmission time τ2 of the second sound is 18m5.
It is 60m5. To explain the execution of the first attenuation control subroutine 28 and the second attenuation control subroutine 31 by replacing the microcomputer 10 with a switch, the attenuation value C5W
At 0, all control terminals L□, L2, L4, and L are open, and the amount of attenuation is minimum. In the damping value CSW, the control terminal L is open, and the other control terminals L2, L4, and L are open. Thereafter, control terminals L1, L2 . The opening and opening of L4 and Ls are combined, and the damping value C8W is a state in which the control terminals L2, L4, and L are closed and only the control terminal L1 is open. Further, the attenuation value CS WL has the maximum attenuation amount when the control terminals L1, L2, L4, and L are closed. As shown in FIG. 3, for example, when the second attenuation control subroutine 31 of the chime sound sending program 25 is executed, the attenuation values C5Wo and C5W are
1. are repeated alternately, and the first attenuation control of the second sound is performed. Next, the attenuation values C5W1 and CS W1 are alternately repeated to execute the second attenuation control.

In this way, the program is executed sequentially, and the attenuation values C3W14 and C3W1s are alternately and repeatedly executed in the time after ik, so that the attenuation amount becomes maximum.

The sound source in the above embodiment may be generated under program control. Alternatively, the frequency oscillated by one oscillator 22 may be divided by a frequency division built into the microcomputer 10 to generate the frequency.

[Effects of the Invention] The intercom calling circuit according to the present invention includes a call button, a chime sound sending means that sends out a chime sound in a preset order according to the operation of the call button, and a resistance value that sends out a chime sound in a preset order according to the operation of the call button. and a speaker that outputs the chime sound attenuated by the digital variable resistor. The feature is that the digital variable resistor attenuates the first and second sounds according to a preset order. Therefore, the number of time constant components such as capacitors and resistors can be reduced, and there is no need to provide adjustment members corresponding to changes in temperature and manufacturing characteristics of capacitors, resistors, etc.

It also has the effect of generating a stable chime sound.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an intercom calling circuit according to the present invention, FIG. 2 is a flowchart of a chime sound transmission program related to FIG. 1, and FIG. 3 is a chime sound waveform diagram of FIG. FIG. 4 is a circuit diagram of a conventional intercom calling device. 11...Digital variable resistor 25...
...Chime sound sending program (chime sound sending means) SW...Call button SP...Speaker agent Patent attorney Mr. Moritani Figure 1 Figure 1 R Figure 2 Figure 3

Claims (1)

[Claims] a call button, a chime sound sending means for sending out a chime sound according to a preset order in response to an operation of the call button, and the chime sound sent from the chime sound sending means with a resistance value changed according to a preset order. 1. A calling circuit for an intercom, comprising: a digital variable resistor that attenuates sound; and a speaker that outputs a chime sound attenuated by the digital variable resistor.