JPS5977751A - Call signal generator - Google Patents

Abstract

PURPOSE:To prevent malfunction of surrounding circuits, by storing plural call signal waveforms in an ROM and obtaining a desired call tone output with synthesis, to attain relay switching of subscriber circuits at a low voltage. CONSTITUTION:An output of a crystal oscillating circuit 13 in a call signal generator 8 is given to a counter IC3 as a clock, the counter IC3 frequency-divides the input signal and gives it to an address terminal of the ROM IC4. The amplitude change against the time change of a required burst signal waveform is stored in the ROM IC4 as a call signal waveform, the address is changed for a prescribed period to read out data, a prescribed tone is synthesized at a resistance adder 14 and the tone is transmitted to a subscriber 6 via an amplifier 4. The call signal is impressed to relay contacts r1, r2 in the circuit 6, an output of an FF11 switches the relay to apply the call signal to an extension 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a ringing signal generator used in private electronic branch exchanges and the like.

Conventional configuration and its problems In a private branch exchange, when an extension telephone receives a call, it is necessary to send a ringing signal with a frequency of 16 to 20 and a voltage of 6 o to SOV to the telephone and ring the bell inside the telephone. be.

The secondary signal source is a ring signal generator, which is implemented in the private branch exchange and is supplied to the telephone via subscriber circuitry that interlaces with the telephone.

Also, the ringtone is generally intermittent and rings for 1 second.

It is normal to repeat the process with a two-second pause.

Conventional ringing signal generators generate the ringing signal continuously at all times, and produce ringing tones by energizing relays in subscriber circuits that interface with telephones that require ringing. An example of the circuit configuration is shown in Fig. 1. 1 is a private branch exchange, 2 is a ringing signal generation circuit, 3 is 16) 1 oscillator,
4 is an amplifier, 5 is an output transformer, 6 is a subscriber circuit, 7 is an extension telephone, and rl and r2 are relay contacts.

In the above configuration, the paging signal generation circuit 2 provided in the private branch exchange 1 includes a 16-channel oscillator 3, and its output (Fig. 2a)
) is supplied to the relay contact r1+”2 via the amplifier 4 and the output transformer 6.Then, the subscriber circuit 6
The relay is switched by the signal from , and the extension telephone 7 is connected for one second to make a call.

A rectangular wave signal (shown in FIG. 2C) having a duration of 2 seconds is supplied.

However, with such a configuration, when the high voltage signal is intermittent with the relay, a spark voltage is generated as shown in Figure 2C.
Surrounding circuits may malfunction. Especially in electronic exchanges, the peripheral circuits are integrated into ICs, so malfunctions are likely to occur, so circuit design is a problem.

This was a big problem in implementation.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned conventional drawbacks and to provide a paging signal generator that has less influence on peripheral circuits.

Structure of the Invention The present invention divides a burst-like calling signal into a plurality of parts corresponding to the time axis, writes the amplitude information in advance in a ROM, and divides this into a counter using the output of a crystal oscillator as a clock. The amplitude information is sequentially read out and amplified to obtain a high-voltage output calling signal.

Description of examples The present invention will be explained below based on one embodiment thereof with reference to the drawings.

In Fig. 3, ~Q11 is the input and output terminal of counter C3, 80~A1° is ROM
The address terminal of the IC4, the output terminals of the Qo-Q6 output ROMIC4, Sl and S2 are output terminals of a calling signal, and the above-mentioned as a whole constitutes a calling signal generator 8.

In the above configuration, the crystal oscillator X, the low resistance 61R7' capacitor C2, the input terminal C1, and the input terminal C2 constitute a well-known crystal oscillation circuit 13, and its output is inputted as a clock signal to the input terminal P1 of the counter circuit C3. The counter C3 divides the frequency of the input signal and inputs the divided signal to the address terminal of the ROMIC4. On the other hand, a calling signal is recorded in advance in the ROM IC 4, and the amplitude change with respect to the time change of the required burst signal waveform is recorded, and the address is changed at a constant cycle to transfer the data to the terminal. -D6 is read out and output, and a desired ringing tone output is synthesized by a resistance adder circuit 14 consisting of resistors R8-R5 and R0' to R4/. As mentioned above, if the ringer is 20)h, on for 1 second, paused for 2 seconds,
ROM IC4 contains 20 amplitude data from address 0 to the first block that will become a sine wave by the resistance adder circuit.
All you have to do is divide it into cycles and write 0 in the remaining percentage. If the address of such a nonvolatile memory is changed at a cycle of 3 seconds, a waveform signal shown in FIG. 5a can be obtained.

Next, FIG. 4 shows the overall configuration of a calling circuit incorporating the above-mentioned calling signal generator and combining it with a sending circuit.
is an AND gate, 11 is a flip-flop (F, F),
12 is a relay r and is connected to the above-mentioned r1.

Reference numeral r2 is the contact point thereof, and these constitute a sending circuit, and the same reference numerals as in FIG. 1 represent the same names. Then the fourth
The overall operation including the sending circuit will be explained with reference to FIGS. The output of the ringing signal generator 8 of FIG. 4 is connected to the terminal S1. S2
is supplied to the relay contact r1゜r, while RO
From the data output terminal D6 of the MIC4, the strobe words shown in FIG.
10 input terminals, respectively. Therefore, by inputting a set signal to the other input terminal of the AND gate 10 at the timing shown in FIG. relay r can be switched by Note that FIG. 6d shows the operating status of this relay r.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, in the subscriber circuit, when the ringing signal is not at high voltage, the relay can be switched;
Does not cause surrounding circuits to malfunction. Also, if the ringing signal generator itself generates an intermittent signal using a relay, etc., it will generate noise, but if the waveform is reproduced by ROM, there is less risk of such a problem, and if the intermittent transient signal is not intentionally generated, If the amplitude of the time is made smaller, for example, as shown in Figure 5a, the noise at the time of intermittent operation can be reduced, and the IC
etc., the subscriber circuit can operate stably.

[Brief explanation of the drawing]

4...Amplifier, 13...Crystal oscillation circuit, 14...Resistance addition circuit, ■C3...
Counter, engineering C4...ROM. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
rJA / Figure 2 Figure 1

Claims (1)

[Claims] The burst-like calling signal waveform is divided into a plurality of parts according to the change in the time axis, and the ROM written in advance and the signal sequentially read from the ROM using a constant speed clock signal are combined to generate the calling signal. A ring signal generator comprising a resistance adder circuit for obtaining a signal.