JPS61150545A - Ringing tone detecting system of packet switchboard - Google Patents

Abstract

PURPOSE:To reproduce a correct ringing tone by extracting pitch data from a data frame, when the data frame sent out of a vocoder has been received, analyzing the frequency of the ringing tone, and also measuring a repeated period of called sound or a voiceless sound of the ringing tone. CONSTITUTION:As incoming processing to a telephone switchboard 102 from a packet switchboard 104, pitch data is extracted from a data frame which has been received at the time of receiving a data frame of before starting a call, whether it is a frequency component of a ringing tone or not is checked, and in case when it it a frequency component of a ringing tone, the number of continuous receptions of the ringing tone is checked. The packet switchboard 1044 is provided with a ringing tone reproducing circuit which is operated over a period for detecting said ringing tone, and a digital signal corresponding to the ringing tone is generated and transferred to a telephone set of a transmitting side through a switching network, and reproduced as a correct ringing tone in the telephone set.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a packet switch. In particular, ring tones (
ringback tone) detection method.

〔overview〕

In a method for detecting that data arriving at a packet switch via a vocoder is a ring tone, ring tone detection is simplified by extracting pitch data from the vocoder output data and checking its cycle. It is something.

[Conventional technology]

Conventionally, the interface of a packet switch was connected to the trunk interface of a regular telephone switch via a vocoder, and when a call was received from the packet switch to the telephone switch, the telephone switch sent a ring tone back to the packet switch. At this time, the vocoder was not in a talking state, so it could not send accurate data frames to the packet switch, and only output data frames valid for pitch data corresponding to the ring tone.

[Problem that the invention seeks to solve]

Therefore, since the packet switch cannot receive an accurate data frame corresponding to the ring tone, there is a problem in that it cannot transmit a normal ring tone to the originating telephone.

The present invention solves the above-mentioned problems, and provides a detection method that allows a packet switch on the originating side to correctly detect that a ring tone has arrived from a vocoder when a telephone exchange transmits a ring tone to a vocoder. The purpose is to provide a method.

[Means for solving problems]

In the present invention, when a packet switch receives a data frame sent from a vocoder, it extracts pitch data from the data frame, analyzes the frequency of the ring tone, and measures the repetition period of voiced or unvoiced tone of the ring tone. The present invention is characterized in that it is configured to recognize reception of a ringing tone when a match with a value to be set as a ringing tone is detected.

[Effect]

When the telephone exchange sends a ring tone to the vocoder, the intermittent cycle is found from the pitch data in the data frame sent from the vocoder to the packet switch, the ring tone is detected from that cycle, and the calling side packet switch is notified of this. do. Packet switches can use this to reproduce the correct ring tone.

〔Example〕

The invention will now be explained in detail with reference to embodiments shown in the accompanying drawings. In FIG. 1, a telephone exchange 102 to which a plurality of telephones 102A input is connected to a vocoder 103 via a trunk interface. This vocoder 103 has v
-24 via the packet switching network 104
Telephone 101B via packet switch 104 of 05
is combined with FIG. 2 shows the structure of an audio data frame. The pitch data P in this indicates a value proportional to the frequency as shown in the example of the following formula % formula %.Also, since the ring tone is expressed by repeating the voiced state and unvoiced state of a specific frequency, the voiced sound A ring tone can be detected from the frequency, the pitch data value for unvoiced sounds, and the duration of each voiced sound and unvoiced sound. This inspection procedure is shown in the flowchart (a) of FIG.

Assume that this procedure is executed when a data frame is received before the start of a call as an incoming call process from the packet switch 104 to the telephone switch 102. Pitch data is extracted from the received data frame in flow 381 of FIG. 3(a), and it is checked in flow 302 whether or not this pitch data is a frequency component of a ringing tone. (
b) In flow 310, it is checked whether it is an unvoiced part. On the other hand, if it is a frequency component of a ringing tone, the number of consecutive receptions of the ringing tone jan is checked in flow 303. Here, if jan=0, it indicates that the state has changed from the unvoiced sound state to the ringing state, which means that the unvoiced sound state has ended. Therefore, in flow 304, in order to process the next unvoiced sound state, the number of consecutive unvoiced sound receptions tbn of the unvoiced sound state that has now ended is set to the number of consecutive unvoiced sound receptions tbn of the previous cycle.
' After copying to n, it is confirmed in flows 305 and 306 that each normal unvoiced state and normal voiced sound state of the ringing tone have been received, and the ringing tone is detected. Also flow 303
．． If the check of 305 and 306 is negative, flow 308
increments the number of consecutive rings received. On the other hand, if it is an unvoiced part in flow 310, flows 311 to 3
For the unvoiced part in step 17, follow the above flows 303 to 309.
Perform the same processing as in .

The packet switch 104 includes a ring tone reproduction circuit that operates during the above-described ring detection period.

This ring tone reproducing circuit generates a digital signal corresponding to the ring tone, and the digital signal is transmitted to the telephone of the calling party via the switching network, and is reproduced by the telephone as the correct ring tone.

Further, the above-mentioned ring detection output can be directly used as control information inside the packet/sevento exchange.

〔Effect of the invention〕

As explained above, the present invention enables the packet switch itself to have a ringing detection function, which has been previously impossible.
The ring tone detected by the terminating packet switch can be easily detected by the calling packet switch. Furthermore, by performing this detection in a packet switch, the efficiency of its use can be increased.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention when a telephone exchange is connected to a packet switching network. FIG. 2 is an audio data frame configuration diagram. FIGS. 3(a) and 3(b) are flowcharts showing pitch data detection procedures. 101...Telephone, 102...Telephone exchange, 103
...Vocoder, 104...Packet switch, 105
...Packet switching network, P...Pitch data in the voice data frame, α1, α2...Minimum and maximum values of the period that can be considered as ringing tone frequency components, jan...Contains the ringing tone frequency component Number of consecutive data frame receptions,
ta' n...Number of consecutive receptions of data frames containing the ringing tone frequency component in the previous cycle, β1, β2...
Minimum and maximum values of the period that can be considered as an unvoiced part, tb
n...Number of consecutive receptions of data frames including unvoiced sound parts, tb' n...Number of consecutive receptions of data frames including unvoiced sound parts in the previous cycle, nal, nat...
Minimum and maximum number of consecutive receptions of data frames that can be considered as normal ringing state, nb, , nbz...
Minimum and maximum number of consecutive receptions of data frames that can be considered a normal ring silence condition.

Claims (1)

[Claims] (1) In a method of detecting a ringing tone arriving from a normal telephone exchange via a vocoder to a packet exchange, the packet exchange is provided with means for extracting pitch data from a data frame sent from the vocoder, and a pitch data repetition period. 1. A ring detection method for a packet switch, comprising means for comparing the period of the ring tone and the period of the ring tone and identifying that the two periods match.