JPH0418841A - Call signal generation device - Google Patents

Abstract

PURPOSE:To switch zero surge energy or low energy by setting a sine wave signal generated by means of driving a single sine wave generation means by means of a clock pulse to be a call signal and providing a pause period in one period. CONSTITUTION:A clock generation means 1 generating the clock pulse and the sine wave generation means 2 generating the sine wave signal of one cycle shorter than the period of the clock pulse within one period of the clock pulse started by the clock pulse are provided. The transmission period of the sine wave signal is set to be a ringing period and the call signal having the pause period in which a difference between the period of the clock pulse and one cycle period of the sine wave signal is a maximum is generated. Namely, a period when a voltage and a current become zero can be provided. Thus, low energy or zero serge energy is switched and the subscriber circuit of an electronic exchange is miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ringing signal generator used in a telephone exchange, and particularly to a ringing signal generator that generates a ringing signal intermittently.

[Conventional technology]

Conventionally, in a calling signal generation device, a calling signal having a fixed ringing period and a fixed pause period as shown in FIG. 4 is generated based on a continuous waveform sine wave signal as shown in FIG. The ringing and pause periods range from 1 to several seconds. The connection of the calling signal to the telephone is achieved by driving the relay 12 by the control circuit 13 using the pause period, as shown in FIG.
The connection destination of the telephone 8 is switched to both the ringer (calling signal generating device) 7 and the subscriber circuit 11 in a silent state.

In addition, in FIG. 5, 9 is a ring trip circuit, and 10 is a ring trip circuit.
12a and 12b are the contacts of the relay 12, respectively.

The conventional calling signal generating device as described above is disclosed in, for example, Patent Application No. 055560 and No. 05556 of 1985.
No. 1, both of which use the output of a sine wave oscillation circuit that performs continuous oscillation as their basic signal.

[Problem to be solved by the invention]

Traditionally, telephone ringing signals have had a fixed pattern, but as the number of subscribers with multiple telephones increases and the service functionality of electronic exchanges improves, users are using a variety of different ringing signals instead of a single ringing signal. Demand for ring signals is increasing. That is, changes in calling signal patterns, by service, by phone product, etc.

Usually, an exchange has only one ring signal generator, so
In order to meet these diverse demands, it is necessary to provide services by operating relays in circuits for each subscriber, but this has been difficult to achieve with the conventional continuous waveform method for the following reasons. In other words, the ring signal uses a sine wave voltage source, but the telephone is generally a capacitive load, and the phase of the current waveform leads the voltage waveform as shown in Figure 6. Since it is selected by itself, its characteristics are diverse, and the lead angle is 9
There is variation with 0゛ being the maximum. If you try to disconnect such a signal with a relay contact, for example, at time 1. If the relay is cut off at <voltage zero point), a large current will be cut off, and a high voltage arc will be generated at the relay contacts due to the inductance of the telephone line and telephone set.

Furthermore, if the circuit is turned off at time 1+, the average current will be the lowest, but a high voltage (the ringing signal is about AClooV) will be turned off, and in either case, a high-energy surge will be generated. Since subscriber circuits and ring trip circuits of electronic exchanges are composed of electronic circuits, these high-energy surges tend to cause malfunctions, and the relays themselves must have high contact durability. Therefore, it is necessary to add a surge protection function to each subscriber circuit, which inevitably increases the size of the circuit.

[Means to solve the problem]

The calling signal generating device of the present invention includes a clock generating means that generates a clock pulse, and a sine wave signal that is activated by the clock pulse and generates a sine wave signal of one cycle shorter than the period of the clock pulse within one period of the clock pulse. a ringing signal having a ringing period as a transmission period of the sine wave signal and a rest period that maximizes the difference between the period of the clock pulse and one cycle period of the sine wave signal. It is the composition.

The sine wave signal from the sine wave generating means is amplified in power and sent as the calling signal to the telephone subscriber line.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

Referring to FIGS. 1 and 2 showing one embodiment, the ringing signal generator fiRG includes a reference clock generation circuit 1, a single-shot sine wave oscillator 2 driven by a reference clock (clock pulse), and a power amplifier 3. and a control circuit 6 for controlling the signal generation period of the generator circuit 1 and the oscillator 2, and outputs a reference clock 4 for driving the relay control circuit 13 in FIG. 5 and a calling signal 5 for the telephone subscriber line.

In this configuration, the oscillator 2 is driven by the rise of the clock from the generating circuit 1, and outputs a single sine wave signal having a period T' shorter than the period T of the clock.

The period T-T' is a rest period, and from the limitation of the current advance angle (maximum 90°) mentioned earlier, T-T' ≧ (T'/4) ten α... (1) If the setting is made so that the current is zero during the rest period. α
The part shown in FIG. 5 is a timing margin for driving the relay 12, and if the pulse width of the clock is α, the driving pulse of the sine wave oscillator 2 and the relay 12 can be shared. If the relay is driven in synchronization with the falling edge of the clock, the relay can be driven when the voltage and current are zero, and high-energy switching surges do not occur, eliminating the need for a surge protection circuit. Further, as for the relay 12, a small relay for low power can be used.

Furthermore, as shown in equation (1), the sent ringing signal has a pause time of 1/4 to 115 times during one cycle, but in the actual ringing state, it also drives the bell, so it may feel particularly strange. Also, a single-shot sine wave oscillator pulse-drives an LC resonant circuit, or a commonly used ROM and D/A
It can be configured with a signal generation circuit using a converter.

〔Effect of the invention〕

As explained above, according to the present invention, a sine wave signal generated by driving a single-shot sine wave generating means with a clock pulse is used as a calling signal, and a rest period is provided in a cycle, so that voltage and A period in which both currents are zero can be provided. This makes it possible to switch to low energy or zero surge energy and downsize the subscriber circuit of the electronic exchange.

Oscillator, 3...power amplifier, 6 controllable circuit, RG...
・Call signal generator.

Claims (1)

[Scope of Claims] 1. A clock generating means for generating a clock pulse, and a sine wave that is activated by the clock pulse and generates a sine wave signal of one cycle shorter than the period of the clock pulse within one period of the clock pulse. generating means, generating a calling signal having a sounding period as a sending period of the sine wave signal and a rest period that maximizes the difference between the period of the clock pulse and one cycle period of the sine wave signal. A calling signal generator characterized by: 2. The calling signal generating device according to claim 1, wherein the sine wave signal from the sine wave generating means is power amplified and sent as the calling signal to the telephone subscriber line.