JPS60165166A - Network signal detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a network signal detection device, particularly a network signal detection device that is connected to a line such as a telephone subscriber line and detects a received signal such as a paging call-5 arriving on the line. connected to a signal detection device.

Home devices such as facsimile machines and data terminal devices are connected to the telephone subscriber line via a network control device 6. These in-home devices are connected to the subscriber line (if R is used,
As is well known, a network control device detects a calling signal that causes the bell of a single telephone to ring, draws the subscriber line to the in-house device, and thereby automatically controls the arrival of calls. In the case of public telephone lines, 18 Hz alternating current is often used as a calling signal.

Conventionally, the detection of the calling signal is performed by using the aftereffect rectifier circuit.
The method of rectifying the signal and determining its direct current level has been widely used. However, this method has drawbacks such as erroneously detecting the dial pulse sent by the telephone of own r1 when making a call, and requiring a long time for detection.

For this reason, the calling signal is converted into a pulse having a repetition frequency twice the frequency of the calling signal by a pair of optical coupling elements connected with opposite polarities, and the calling number B is detected by counting the period of this pulse. There is a method. In this method th, in the case of a calling signal of 18 Hz, the pulse frequency or 3
2Hz, so the calling signal is 10pps and 20p.
It has a distinct feature that distinguishes it from the PS dial pulse.

However, if the characteristics of the light emitting diodes and transistors included in the pair of optical coupling elements used are not substantially matched, the waveform clip level in both polarities of the alternating current waveform of the calling signal will become unbalanced. Therefore, depending on the state of the line, the pulse output from the optical signal J1 combining element may have an unbalanced pulse width or repetition period, and it may not be possible to detect a ringing signal.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to eliminate the drawbacks of the prior art and to provide a network signal detection device that can appropriately detect a paging signal without being affected by variations in elements or line conditions. shall be.

1-Reduction The configuration of the present invention will be described below based on one embodiment.

Prior to detailed description of the present invention, a prior device will be described with reference to FIG. For example, a telephone subscriber line 10T and a ring line 10R of a telephone subscriber line 10 housed in a central office are connected to a telephone set 14 via switching contacts +2a and +2b, respectively, and to a domestic device 14 such as a facsimile machine 6 or a data terminal equipment. or connected as shown.

Between the telephone set 14 and the subscriber line 10, as shown in the figure,
Resistor 20, capacitor 22, varistor 24 and resistor 2
6 is connected, and a series connection of a resistor 28 and a pair of optical coupling elements 30 is connected in parallel with the resistor 28. This photocoupler pair 30 includes light emitting diodes 32 and 34 connected with opposite polarities, and a phototransistor 36 optically coupled to receive light from the corresponding light emitting diodes.
and 38, and phototransistors 36 and 38 are biased through resistor 31 with positive 11j3aVcc. The collector output 40 is input to the home device 16 through the amplifier 35.

The optical coupling element pair 30 converts a discharge signal of, for example, 16 Hz, which arrives at the subscriber line 10 from the central office, into a pulse having a repetition frequency of 32 Hz, which is twice that signal, and outputs the pulse to an output 40. A calling signal is detected by counting the period of this pulse. When the calling signal is detected, the home device 16 prepares for the subsequent transmission control procedure υ11, switches contacts 12a and 12b to the home device 16 side, and thereafter the call progresses.

However, the light emitting diode 1 included in the optical coupling element pair 30
If the characteristics of 32.34 and phototransistor 38.38 are not substantially matched, for example, as shown in FIG.
The waveforms 102 and 104 become unbalanced.9Therefore, depending on the line configuration 7M4, the pulses output from the optical coupling element pair 30 may have unbalanced pulse widths and repetition periods, making it impossible to detect a correct calling signal. Sometimes.

To solve this problem, in an uninvented embodiment, a second
As shown in the figure, a network signal detection device 50 is connected to the output 40 of the optical coupler pair 30, and the detection result is 114 and 52
is input to the home device 18. Also, in response to this, switching contacts +2a and 12b are switched to the home device 16 side! il
It is configured so that it can be replaced. In this figure, the same components as those in the embodiment of FIG. 1 are designated by the same reference number a.

The network f1MI control device 50 has a processing device 54 as shown in the figure, and the processing device 54 performs detection and determination of a paging signal. The human power port 56 has two stroke count circuits 58, 60, a control signal generating circuit 62, 64, and υ as shown in the figure.
・AND gates 6G and 68 are connected, and the output 40 of the optical coupling element 30 is directly connected to the control signal generation circuit 62, and the output 40 is connected to the control signal generation circuit 64 via an inverter 70.6 Optical coupling When the ringing signal 100 as shown in FIG. A pulse 40 having the following values is output ((C) in the same figure). This is for example the ringing signal 1
If 00 is an AC signal of 16 Hz, it is output as a rectangular wave with a repetition frequency of 32 Hz.

In other words, the frequency has been multiplied. Such frequency multiplication is effective in obtaining a sufficient number of detections in a short period of time and performing highly reliable signal detection. This pulse is input as is to one control signal generation circuit 62, and is inverted and inputted to the other control signal generation circuit 64 by an inverter 70 ((F) in the figure). Note that in the following description, reference numerals indicating signals are represented by reference numerals of signal lines through which the signals are carried.

Control signal generation circuits 62 and 64 may have the same configuration. For example, the control signal generation circuit 62 generates a pulse 40 on the human cuff 2.
In response, one output cuff 6 receives a gate signal 76 (see figure (D).
)), which remains high for a period T1 from, for example, the odd-numbered rising edge of the input pulse 40 to the following even-numbered rising edge. A clear signal 80 ((E) in the figure) is outputted to the other output 80, and this signal stays at a high level from the next falling edge of the input pulse 40 following the falling edge of the gate signal 76 to the falling edge. The control signal generation circuit 84 also operates in the same way as the control signal generation circuit 62 by simply inputting the inverted version of the signal 40 to the inlet cuff 4, and is shown in FIG.
) and a gate signal 78 and a clear signal 82 as shown in (H) are output.

A paging signal that has arrived at the subscriber line 10 from the central office is blocked by a capacitor 22 and is input to a pair of optical coupling elements 30 . Regarding the AC component, the threshold values 102 and 104 of the photocoupler pair are equally on the bipolar side with respect to the O level 106,
That is, if they are set symmetrically, the pulse width TI of the gate signal 76 and the pulse width T2 of the gate signal 78 should be substantially equal. However, if there are variations in these, as shown in FIG. 3(B), for example, the control signal generation circuits 62 and 64 will generate gates with different pulse widths Tl and T2, as shown in FIG. 3(11) and (G). signal 78
and 78 are generated.

Gate signals 76 and 78 are connected to AND gate 6, respectively.
6 and 68, and the AND gate 6
The other inputs 84 and 86 of 6 and 68 are supplied with a reference clock 90 from a reference clock generator 88. Outputs 92 and 94 of AND gates 66 and 68 are.

They are connected to one input of counting circuits 58 and 60, respectively, and the other input of the latter receives clear signals 80 and 82 from corresponding control signal generation circuits 62 and 84, respectively.

AND gate 66 and U68 output reference clock 80 only during the period when gate signals 7B and 78 are at high level. Divider circuits 58 and 80 can then count the time lengths of periods T1 and T2 of gate signals 76 and 78 by counting the reference clocks appearing at inputs 92 and 94, respectively.

This old teaching value is read into the processing device 54 via the single input port 56, and is reset by clear signals 80 and 82 which occur immediately 111j when the next high level gate signal is input.

The processing device 54 can then calculate the read cycle value and detect the reception of the calling signal +00. For example, as illustrated in FIG. 3, an imbalance in thresholds 102 and 104 will result in different pulse widths T1 and T2. The processing device 54 sends a ringing signal 10 to the subscriber line 10.
0 begins to arrive, successive periods T1 and T2 are measured for the first high level period of gate signals 76 and 78. Therefore, until the next high level arrives, the sum of both periods TI and T2 is calculated, and an average calculation is performed by multiplying the sum by 172. This shortens the period T of the calling signal 100, that is, (T1+72)/2.

By repeating such cycle measurement and averaging calculation for one cycle or a suitable number of cycles of the ringing signal, that is, for at least two successive cycles of the gate signal, the cycle T can be accurately detected. can. If the detection result is within a predetermined tolerance, it can be identified as a paging signal and clearly distinguished from other signals such as dial pulses.

When the calling signal is detected in this way, the processing device 54 instructs the home device 16 to prepare for receiving a call, and also switches the 9 switching contacts 12a and +2b to the home device 16 side to proceed to the subsequent call connection sequence. .

According to the present invention, the calling signal is identified by multiplying the calling signal in this manner and calculating the average period over a plurality of adjacent periods. Therefore, there is no erroneous detection due to variations in elements used for signal detection or line conditions, and the calling signal can be appropriately detected.

[Brief explanation of drawings]

FIG. 1 is a functional diagram showing an example of a prior art paging signal detection device, FIG. 2 is a block diagram showing an embodiment of a network signal detection device according to the present invention, and FIG. 3 explains the operation of the device in FIG. 2. FIG. 3 is a signal waveform diagram for Noble 10, telephone subscriber line 30, optical coupling element pair 50, network signal detection device 54, processing device 58,60. , counting circuit 8'2, 84. , control signal generation circuit 8Et, 88. , 7ND gate 70, , inverter 88, , reference clock generator patent applicant Ricoh Co., Ltd.

Claims (1)

[Claims] A network signal detection device connected to a line and detecting a received signal arriving from the line, the device converts the received signal into a signal with a corresponding value of 4 (■) and multiplies it. a multiplying means for forming a binary signal having a repetition frequency twice that of the received signal; an X1 number means for counting the period of the binary signal; and a processing means for calculating the average value 16 of the discrepant period; A network signal detection device characterized in that it identifies the arrival of a value t.