JPS6048653A - Howler signal transmission system - Google Patents

Abstract

PURPOSE:To simplify the subscriber circuit of a telephone exchange by using a frequency sweep signal as a howler signal. CONSTITUTION:A digital tone generator 204 generates a digital audible tone having a period of T (e.g., 200ms), sweeping the frequency from f0 (e.g., 200Hz) to f1 (e.g., 4kHz) at a maximum output level of 3dbm and supplies the tone to a talking circuit 102 via a time division switch 203. The circuit 102 transmits a PCM signal input 205 to a telephone set 100. since the resonance is generated by specific resonance frequencies existing in a handset and between the handset and a desk on which the handset is placed or other object, and the acoustic level is increased apparently, the recognition by human being is attained easily by using a signal repeated the frequency sweep as a howler signal.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to subscriber circuits in telephone exchanges.

In particular, the present invention relates to a method for sending a Howler signal to a subscriber as a warning signal when the subscriber is off the hook for a long time.

[Description of prior art]

Conventionally, the subscriber circuit has four Howler circuits, as shown in FIG. 1, for sending out signals. In FIG. 1, when transmitting a howler signal, a telephone 100 is switched from a communication circuit 102 to a howler signal generation circuit 103 by an interlocking relay 101. Howler 1eT→3- generation circuit 103 is -
48 ■ E1 protection resistor 105 connected to battery 104
．． It is connected to the telephone 100 via 106.

107 is a subscriber loop monitoring circuit, and a protection resistor 105
Monitor all DC current flowing through the When the receiver is hung up and the subscriber loop becomes "open", a subscriber recovery signal is sent to the recovery detection line 108. This detects that the handset has been returned to normal.

In this conventional howler signal generation circuit 103, the howler transmission signal is generally a single frequency sine wave of about 800 Bz, which is a frequency that is good for human auditory sense, from +IQ dBm to +25 dBm i7 degree dog (5 houses;
He was used to grow a beard in Type 4. Therefore, there is a special UJ for howler signal transmission.
The f+monthj relay 101 and the subscriber recovery detection circuit were required, which had the drawback of making the exchange expensive and expensive.

[Purpose of the invention]

The present invention solves the above-mentioned drawbacks and provides a howler signal transmission method that can obtain a howler signal at a level sufficient for human hearing from a normal communication circuit without providing a special signal generation circuit. The purpose is to provide.

[Features of the invention]

The present invention uses a signal in which the frequency of the fundamental frequency component changes over time in the howler signal transmission method of the subscriber circuit of a telephone exchange as the howler signal.
Features.

[Explanation based on examples]

Embodiments of the present invention will be described with reference to the drawings. Second
The figure is a block diagram of a howler signal transmitting device according to an embodiment of the present invention. In the figure, the same equipment and circuits as in Figure 171 are indicated by the same symbols as in Figure 1. One telephone set is connected to a telephone call circuit 102.

The telephone call circuit 102 is connected to a digital tone generator 204 via a time division switch 203.

The operation of the howler signal transmitting device configured in this way will be explained.

In FIG. 2, telephone 1(1) is directly connected to telephone circuit 102. Telephone 1(1) is directly connected to telephone circuit 102. The total circuit 102 is a PcM signal human power 20
5 to the telephone 100. The digital circuit generator 204 is a circuit that generates a digital signal (see, for example, patent application No. 1983, L63794). Here, an example of a signal generated by the digital tone georator is shown in FIG. That is, the frequency is f in T time periods. Sweep from 14 inches. As a specific example,
+3dB from 200Hz to 4kHz i every 200m5
m rectangular wave signals are swept. Here, POM
The maximum output level of the μ-law codec (CODEC!) is +3aBm, and the same is true for the A-law codec of C1t. By sweeping the frequency, even a maximum output level of +3d13m can be sufficiently recognized by human hearing. That is, there are generally some unique resonant frequencies in the audio frequency range between the handset and the desk or other object on which it is placed.
6. When an audible frequency of about T-1m is swept over a wide band, resonance occurs at the above-mentioned unique resonance frequency, and at this point?
, the sound level can be made apparently higher. Saitama, J
S] Wave number By using the wave number as a howler signal, which is a full trigger repetition signal, human recognition can be facilitated.

As described above, in the method of the present invention, in order to use a relatively low level audio signal as a howler signal, the special coverr signal generation circuit and the switching circuit for transmitting howler (Fi) are also used to transmit howler signals. There is also no need for a subscriber recovery detection circuit inside, making it possible to simplify the circuitry of the telephone exchange and reduce hardware costs.

The howler signal of the present invention is not limited to the waveform shown in FIG. 4] is a howler signal waveform diagram of an excitation method according to an embodiment of the present invention. This howler signal is T'
li, the frequency within 'i. Sweep from f to (7,
Then, within (T-T') time, sweep the loss of 1-83 from fo to 2-4 and return kI:j゛.

FIG. 5 is a howler signal waveform diagram of another practical 7AI '('', ' method of the present invention. This howler signal changes frequency from fl to f within a time period of 1.1 from t.
, and changes the frequency from f to f within the elapsed time from t to t2. It sweeps up to

Further, the signal to be swept may have any waveform such as a sine wave, a rectangular wave, a triangular wave, or a sawtooth wave. In addition, although the signal level is generally set at the highest output level, some modulation may be added.

The details of the communication circuit 102 are omitted, but the circuit example f:
It is shown in FIG. 600 (d hybrid transformer, 6
01 is a decoder, 602 is a coder, and 603 is a subscriber loop detection circuit.

In the above embodiment, a digital telephone exchange has been described, but the present invention can also be used in an analog type telephone exchange. The present invention can also be applied to J using a circuit similar to the howler signal sending circuit described in the conventional example.

〔Effect of the invention〕

As explained above, the non-invention has the excellent effect of transmitting a howler signal from a communication circuit by using a frequency-swept signal as a howler (i1'4). ]'; One circuit can be simplified and an economical external telephone exchange can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional howler signal transmitting device. FIG. 2 is a block diagram of a howler signal transmitting device according to an embodiment of the present invention. FIG. 6, FIG. 4, and FIG. 5 are time charts showing an example of the frequency sweep of the howler signal. FIG. 6 is a circuit diagram showing an example of the communication circuit (201) of FIG. 2. 100...telephone, 101. ...Switching relay, 10
2...Telephone circuit, 103...Howler No. 1 generation circuit, 104...Call batch l]-1105...Protection resistor, 106...Protection resistor, 107...Subscriber loop monitoring circuit , 108... Recovery detection signal line, 203.-
・Time division switch, 204...Digital tone generator, 205...Digital human power No. e, m...
Hybrid transformer, 601...decoder (DEC
), 602 . . . course (COD), 603 . . . subscriber loop detection circuit (DET). 1st eye shoulder 2 times Fr, eq. Yu 3 Zujin 4 Kasumi M 5 Zukan 6 times

Claims (1)

[Claims] (1) In the 7-waller signal transmission method of the subscriber circuit of a telephone exchange, the method is characterized in that the fundamental wave frequency gold, at least in the audible frequency range, is changed over time and is used as the howler signal. Signal transmission method.