JPS5875363A - Transmitting circuit of public charging pulse - Google Patents

Abstract

PURPOSE:To improve the suppression properties of charging noises and to decrease the working delay time in a forcible disconnection mode, by driving an equivalent feed power supply in a current supplying circuit with a constant current source and controlling the constant current source with the output signal of a filter which feeds the step signal for transmission of the charging pulse. CONSTITUTION:The control signals given from charging pulse transmission controlling terminals 46 and 56 are fed to filter parts 61 and 71 consisting of constant power supply integration circuits 43 and 53 and CR integration circuits 42 and 52 via buffer circuits 44 and 54, respectively. The outputs of the parts 61 and 71 are fed to current supply controlling constant current parts 41 and 51 which generate current signals for control of the current supply properties. The current supplying circuits 40 and 50 which supply currents to a subscriber circuit 2 are controlled by an equivalent feed power supply proportional to the output signals of the parts 41 and 51. The circuits 40 and 50 are connected between the communication line and earth/battery, and each circuit is converted into a double circuit in which the output sides have adverse polarities to each other between the normal side 62 and the reverse side 72. Thus the suppression properties can be improved for the charging noises to realize an integrated structure of circuits.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to sending out a public charging pulse in an automatic telephone exchange that immediately sends out a charging pulse to a public telephone.

FIG. 1 shows an example of a conventional configuration in which a charging pulse sending trunk (TRK) is used by connecting to a subscriber terminal 1 via a subscriber line 2. LC filter (LCF) consisting of .7 and capacitor 5.8 and current reversal relay contacts 9, 10, 11.1
2, a current supply circuit 13, and other electromagnetic components.When sending out charging pulses, the current reversing relay contacts 9, 10, and 11. ), and transmits a low-noise billing pulse LAI as shown in FIG. 2 to the subscriber terminal. In FIG. 2, 20 is a control signal for current reversing relays 9 and 10, and 30 is a control signal for current reversing relays 11 and 12.

Conventional trunks for charging and transmitting signals are made up of electromagnetic parts and cannot be made smaller, lighter, or more integrated, and the noise removal filter always operates when connecting or disconnecting circuits, making it difficult to accommodate and store responses. The signal transmission time becomes longer, and even during forced disconnection, the subscriber loop current is 1. It takes about 100 m5 for the pulse to become zero, and the public charge pulse sending circuit has a long invalid hold time.

The present invention has a configuration in which an equivalent power supply in a current supply circuit is driven by a constant current source, and the constant current source is controlled by an output signal of a filter that receives a step signal for sending charging pulses as input. The present invention provides a charging pulse sending circuit for public use, which is suitable for computerization or integrated circuit implementation, has excellent charging noise suppression characteristics, and can shorten operation delay time during forced disconnection.The present invention will be described in detail below. do.

FIG. 4 shows a configuration example of the present invention, in which the same circuit is provided on the normal side and the reverse side, and the circuits are arranged so that the polarities of the outputs of the A and B lines are opposite.

1 is a subscriber terminal, 2 is a subscriber line, 40.50 is a current supply circuit, and 41.5 is a constant current source for controlling the current supply circuit. 42.52 is a CR integration circuit, and 43.53 is a constant current integration circuit, which constitute a filter section 61.71. 44.54 is a buffer circuit, 45.55 is a filter control switch, 46.56 is a billing pulse sending control terminal,
6θ is a control terminal for a filter control switch.

Next, the operation will be explained. Billing/Guru transmission signals 47.57 shown in FIG. 3 are applied to the billing/Guru transmission control terminals 46, 56 in FIG. 4, respectively. When transmitting the response storage signal (T1 time), if the filter control switch 44.45 is closed, the charging pulse transmission signal 47.57 is applied to the input of the buffer circuit 44.54, and the buffer circuit 4
The output of 4.54 is a constant current source for direct current supply control 41.5
1, and by operating the current supply circuit 40.50 by the output of the constant current source 41.51 for current supply control, it immediately responds to the billing pulse sending signal as shown in the subscriber loop current LA2 in FIG. It is possible to send a response acknowledgment signal. Furthermore, when transmitting the billing pulse signal (time T2) shown in the subscriber loop current LA2 in FIG. 3, the billing pulse sending signal 47 degrees is 57 connects a filter section 61.71, which is composed of constant current integration circuits 43, 53 and CR integration circuit 42.52, which have a transfer function as shown by the solid line in FIG. Through, current supply circuit 40.5
Constant current source 4J for current supply control that creates an equivalent power supply of 0
, 51, the subscriber loop current LA of FIG.
As shown in Figure 2, smooth current changes can be used to charge and charge subscriber terminals.
It can also send out virus signals.

Next, when the supply current to the subscriber terminal is quickly cut off at time T3, the filter control switch 45, 55 is closed via the filter control signal terminal 60 in the same manner as in the case of sending out the response accommodation signal described above. 61.7J, the charging/bus sending control signal 46.56 drives the constant current source for current supply control via the buffer circuit 44.54, so the current supply circuit 40.50 changes accordingly. ,
It is possible to quickly cut off the power supply current to the subscriber terminal as shown at T3 of the subscriber loop current LA2 in FIG.

FIG. 6 shows a specific configuration of the embodiment. Buffer circuit 30
7,407 is an electronic switch y'zoo, 2oθ and resistors 101, 102 which are opened and closed by a charging pulse sending control signal.
, 103 and 201, 202° 203 is received by the operational amplifier 1o4°, 204, and outputted to the constant current integrating circuit 302 at the next stage of the operational amplifiers 104, 2θ4, and the constant current of the constant current integrating circuit 302. Source 11o.

11 and 210 and 211.

Constant current integration circuits 302 and 402 are operational amplifiers 108°2
08, resistance 105, 107, 205, 207, capacitance 10
6, 206; a current integrating circuit consisting of constant current sources 11θ, iii driven by the integrating circuit; 210, 211; and capacitors 112, 212. Also, the next stage resistors 113, 114, 213, 214
CR integration circuit 303, 40 with capacity 115°215
3. And constant current integration circuits 302, 402
and CR integration circuits 303 and 403 constitute a filter section 3o4°4θ4. The said filament part 3θ4.404',
11 is given by < f(s) as well known for the step signal input, and has an output characteristic as shown by the dashed line in FIG. 5. Here, at the time of to shown in FIG. The constant current circuits 110, 111, 210, 211 are the buffer circuit 3.
07 and 407, it is saturated and output voltages as shown by the solid line in FIG. 5 are generated at vA and VB. The constant current section 305°405 for controlling current supply is an operational amplifier 116,
216, resistor 117°217, transistor 118,2
18, as is well known, the operational amplifier 11
It has a function of converting a voltage change at the input V of the op-amp 116 into a current change divided by a resistor 117.217. In this example, voltage-current conversion is configured by operational amplifiers 116 and 216, but resistor 117.2
17 and transistors 118 and 218 only. Therefore, the smoothly changing voltage shown by the solid line in FIG.
The changes in the collector currents of the transistors 118 and 218 of No. 5 also change smoothly like the changes in the voltages VA and vB. The current supply units 306- and 307 set the DC resistance values of the resistors 126 and 127 to be equal to the DC resistance values of the resistors 216 and 217, and set the mirror ratio of the current mirrors 119 and 219 to 81. Transistor 124°214 and operational amplifier 1 with ratio b
22, 222, resistor 121° 123. The amplification factor determined by 221, 223 is A1, the constant current section 305 for current supply control.
, 405, the collector current of the transistors 118, 218 is I. The current L supplied by the current supply units 306 and 406 is the output current of the constant current unit 305 and 405 for current supply control, where Re is the subscriber terminal (load resistance including the line).

It can be seen that the current supply units 306 and 406 form an equivalent power supply. Therefore, if the output of the constant current sections 305, 405 for current supply control as described above changes smoothly, the constant power supply of the current supply sections 306, 406 changes smoothly, and accordingly, the power supply to the subscriber terminals changes smoothly. The current IL also changes smoothly. This series of operations is carried out by the charging pulse sending signal 47 shown in FIG.
, 57, it becomes possible to send a billing pulse signal as shown at T2 of the subscriber loop current LA2 in FIG. 3 to the subscriber terminal.

Next, the filter control switch is an electronic switch 109°20
9 and 409, 509, the buffer circuit 3
The output of 07, 407 and the input of the constant current section for controlling current supply are connected to electronic switches 109, 2 via resistors 114, 214.
Connect with 09. The filter control switch closes the electronic switches 109, 209 according to the filter control signal.

Then, the output signals of the buffer circuits 307 and 407 are
14° 214, and is transmitted to the input of the constant current section 305, 405 for current supply control via the capacitors 115, 215.

If the time constant determined by the resistors 114, 214 and capacitors 115, 215 is made sufficiently small, the buffer circuit 30
The output signal 7,407, that is, the step pulse, is applied to the current supply control constant current sections 305, 405, and the current supply section 306, 406 is supplied with a steno pulse current. Therefore, since the current supply units 306 and 406 form an equivalent power supply as described above using a step-noise current, the current supplied to the subscriber terminal from the current supply units 306 and 406 also changes in a step manner. Therefore, it is possible to send out the response accommodation signal shown at time Tl of the subscriber loop current LA2 and the forced disconnection signal shown at time T3.

In addition, the electronic switch for filter control has a resistance of 114°21
4, the electronic switch for filter control is connected to the constant current section 305 for controlling the current supply through the capacitor 115.
, 215, the resistor 11
4,214 may be omitted.

According to the present invention, there are advantages in that it is easy to reduce the size and weight, and it can be computerized, and it can be used in public billing pulse sending circuits such as automatic telephone exchanges.

[Brief explanation of drawings]

Figure 1 is a circuit diagram showing a conventional billing pulse sending circuit;
1 is a time chart showing the operation of FIG. 1, FIG. 3 is a time chart showing the operation of an embodiment of the present invention, and FIG. 4 is a block diagram of a billing pulse sending circuit according to an embodiment of the present invention.
FIG. 5 is an output waveform of the billing noise removal filter of the embodiment, and FIG. 6 is a circuit diagram showing a specific example of FIG. 4. 1...-Subscriber terminal, 2...Subscriber line, 16,71
゜304.404... Filter section, 40, 50, 30
6゜406...Current supply unit, 301...Battery, 41
, 51゜305.405... constant current section for current supply control, 45j55.109, 209, 409, 509...
Filter control switch, 44, 54, 307, 407・
...Buffer circuit, 46, 56, 100, 200, 40
0゜500...Billing pulse sending-control terminal, 60...
・Control terminal for filter control switch. Patent Applicant Oki Electric Industry Co., Ltd. Nippon Telegraph and Telephone Public Corporation NEC Corporation Hitachi Ltd. Continued from page 1 ■Applicant Hitachi Ltd. 5-1 Marunouchi-chome, Chiyoda-ku, Tokyo ■Applicant Fujitsu Stock Company Address: 1015 Kamiodanaka, Nakahara-ku, Kawasaki City Procedural amendment (voluntary) Showa 47.21-3B Commissioner of the Japan Patent Office Tol Indication of the case 1982 Patent Application No. 172154 2 Name of the invention Public billing/transmission circuit 3 Relationship with the case of the person making the amendment Patent applicant address (〒105) 1-7-1 Toranomon, Minato-ku, Tokyo
No. 2, 1 agent (4 others) residence, location (〒
105) Correct No. 12, 1-7, Toranomon, Minato-ku, Tokyo. Scope of Claims (1) A current supply control device that generates a current signal for controlling current supply characteristics, which is composed of a constant current integrator circuit and a CR integrator circuit that receives a control signal for billing and system sending as input. A circuit consisting of a current source, and a current supply section that is connected between the communication line, the ground, and the battery and supplies current to the subscriber terminal with an equivalent power supply proportional to the output signal of the constant current source for controlling the current supply. (2) A public billing and bus signal transmission circuit having two circuits and connected so that the output sides of both circuits have opposite polarities to each other. a filter section constituted by a current integration circuit and a CR integration circuit; a constant current source for current supply control that receives the output of the filter section as input and generates a current signal for controlling current supply characteristics; a switch that can be opened and closed by a control signal between a subscriber terminal and an input terminal of the constant current source for controlling current supply, which is connected between the battery and an equivalent power supply proportional to the output signal of the current source for controlling current supply; When the switch is closed, the current supply control constant current source is directly driven by the billing and system sending control signal, and the current supply unit supplies the current to the subscriber terminal using the billing and system sending control signal. 1. A public billing/returning circuit characterized in that it has two circuits each consisting of one circuit for rapidly cutting and one for rapidly supplying current, and that the output sides of both circuits are connected so that the polarities are opposite to each other.

Claims (2)

[Claims] (1) A buffer circuit that drives a filter section constituted by a constant current integrating circuit and a CR integrating circuit that receives a control signal for sending billing pulses as input, and also provides a bias for the constant current integrating circuit, and an output of the filter section. a constant current source for controlling the current supply which generates a current signal for controlling the current supply characteristics with input as input; A public billing pulse comprising two circuits each comprising a current supply unit that supplies current to a subscriber terminal using an equivalent power supply, and the output sides of both circuits are connected to each other so that the polarities are opposite to each other. Sending circuit. (2) A buffer circuit that drives a filter section constituted by a constant current integration circuit and a CR integration circuit that receives a control signal for billing/bus transmission as input, and also provides a bias for the constant current integration circuit, and the filter section. a constant current source for controlling current supply which generates a current signal for controlling current supply characteristics by inputting the output of a current supply section that supplies current to the subscriber terminal with a proportional equivalent power supply;
A switch that can be opened and closed by a control signal is provided between the output of the buffer circuit and the input terminal of the constant current source for controlling current supply, and when the switch is closed, the constant current source for controlling current supply is directly controlled for sending charging pulses. The output side of both circuits has two circuits, each of which is driven by a buffer circuit that inputs a signal, and which quickly cuts and quickly supplies the current supplied to the subscriber terminal by the current supply section in response to the billing pulse sending control signal. A public billing/gurus transmission circuit characterized in that the circuits are connected so as to have opposite polarities to each other.