JPS60140969A - Transmitting system of audio signal sound - Google Patents

Abstract

PURPOSE:To simplify a signal generation circuit and to obtain an audio signal sound transmitting system to facilitate heading of an intermittent signal by executing intermission of an audio signal sound on a time switch of a time-sharing channel. CONSTITUTION:Receiving commands from a central processing unit, a microprocessor muP controls a time switch T using the receiving time as an origin as follows: after zero second bus connection in the direction of (x) (y), after one second bus cutting, after 3sec bus connection in the direction of (x) (y), and after 4sec bus cutting. If this sequence by 3sec frequency is repeated, a ring- back tone such as 1sec-on and 2sec-off can be transmitted at the prescribed time for an optical time slot (y). As widely known, multiplex connection can be possible in a time switch of sequential writing and random reading, and as a result, if multiplex processing is carried out for plural output time slots, optimum phase audio sounds their terminals can be simultaneously transmitted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a system for transmitting an audible tone in a digital telephone exchange.

[Prior art]

Conventionally, an audible signal tone transmission method in a time-division switch has been a circuit that time-sequentially generates digital patterns of audible signal tones, such as dial tones and ringback tones, each having a specified frequency, output level, and intermittent period. It has been common practice to connect a signal input terminal and a subscriber terminal to which the signal is to be sent via a time-division communication path.

FIG. 1 shows an example of a method using a conventional audible signal tone generation circuit. The audible signal tone generation system shown in the figure includes an audible signal tone generation circuit TNG, a multiplexing/demultiplexing circuit MUX/DMUX
, a time switch T, and a time switch control microprocessor pP.

The audible signal tone generating circuit TNG is composed of a digital bang generating circuit TONK which generates a digital pattern of a signal with a frequency and level corresponding to the audible signal tone, and an intermittent circuit INT which interrupts the digital pattern at a predetermined period. In addition, the digital bang generation circuit TONE.

It is assumed that the intermittent circuit INT operates in a time-division manner because it generates a plurality of types of signals.

In this case, taking Japan as an example, the ring back tone is a 1 second on, 2 second off signal, so as shown in Figure 2, a three-phase ring bank tone with a phase shift of 1 second is prepared. However, a central processing unit (not shown) usually refers to the phase signal int to determine the phase to be used, and instructs the microprocessor μP to control the switch T.

However, in the conventional system, it is necessary to intermittent the signal tone on the audible signal tone generation circuit side, but especially for signal tones with a long intermittent period such as a ring bank tone, in order to minimize the connection delay of the exchange, It is necessary to prepare multiple phase signals with different intermittent phases, and select and connect the appropriate phase for each call, which has the disadvantage of not only increasing the number of circuits but also complicating the connection control procedure.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned drawbacks, and it is possible to simplify the signal generation circuit and to locate the beginning of the intermittent signal by intermittent audible signal tones on the time switch of the time-division communication path. The present invention provides an audible signal tone transmission method that facilitates this.

[Structure of the invention]

The time-division telephone exchange that performs audible signal tone connection control according to the present invention includes a sequential writing, random reading type time switch, and is connected to an input terminal of the time switch, and provides telephone exchange services such as dial tone, busy tone, and ringback tone. a digital pattern generation circuit that time-sequentially generates a digital pattern of a signal with a frequency and transmission level corresponding to the audible signal sound necessary for configured.

In such a table configuration, the present invention transmits the necessary audible signal tone to the telephone subscriber terminal by turning the time switch at predetermined time intervals without closing or opening.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. Incidentally, FIG. 3 is a block diagram showing an embodiment of the audible signal tone transmission system of the present invention.

The embodiment shown in the figure includes an audible signal tone generating circuit TNG1, a multiplexing/demultiplexing circuit MUX/DMUX, a time switch T, b
and a microprocessor μP for time switch control.

The audible signal tone generating circuit TNG is composed of a digital pattern generating circuit TONE that generates a digital pattern of a signal with a frequency and level that is in harmony with the audible signal tone, and is different from the conventional example shown in FIG. 1 described above. , does not have an intermittent circuit INT. Therefore, this audible signal tone generating circuit TNG
continues to generate a digital pattern at a predetermined frequency and level regardless of the intermittent period of the signal.

In such a configuration, let us consider a case where a ringback tone input in incoming time slot X is transmitted to a subscriber in outgoing time slot y.

Microprocessor μP receives instructions from central processing unit
starts from that point and controls the time switch T as follows.

After 0 seconds, "Path connection in x-+y direction" After 1 second, "Path disconnection" After 3 seconds, "Path connection in input → y direction" After 4 seconds, "Path disconnection" If you repeat this every 3 seconds, you will get For any time slot y, a ringback tone of 7&1 seconds on and 2 seconds off can be transmitted from a desired time as shown in FIG.

As is well known, multiple connections are possible in sequential write and random read time switches, so if the above process is multiplexed for multiple output time slots, the optimal phase can be achieved for those terminals. It is clear that audible sounds can be transmitted simultaneously, and similar processing is also possible for other signal tones.

〔Effect of the invention〕

As explained above, the present invention simplifies the audible signal tone generation circuit by directly turning on and off the sequential write and random read time switches according to the intermittent period of the audible signal tone. This has the effect of making it easier to locate the beginning of the audible signal sound.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional audible signal sound transmission system,
FIG. 2 is a waveform diagram showing the phase relationship of the conventional ringback tone shown in FIG. 1 as an analog waveform, and FIG. 3 is a block diagram showing an embodiment of the audible signal tone transmission system of the present invention. TNG: Audible signal generation circuit T: Time switch μP: Microphone 4 Processor Applicant: NEC Corporation - (NJ rv)

Claims (1)

[Claims] Sequential writing, random reading format time switch number/vi connected to the input terminal of the time switch, frequency/transmission corresponding to audible signal tones required for telephone exchange services such as dial tone, tones, ring back tones, etc. 1. An audible signal sound transmission system comprising: a digital bang generation circuit that generates a digital pattern of level signals in time series; and a microprocessor that controls opening and closing of the time switch at predetermined time intervals.