JPS5932942B2 - Signal tone transmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal tone transmission system, particularly in a signal tone transmission system such as a telephone switching system that transmits a voice signal and an audible sound signal such as a ring tone or a busy tone. For example, in order to compress the voice into a band of 2 or 4 bits, it is configured to perform band compression using spectrum information (formant, etc.) of the voice, and by using the band compression, audible sounds such as the above-mentioned ringing tones can be compressed. This relates to a signal transmission method that solves the problem of signal loss.

2. Description of the Related Art Conventionally, voice signals and audible sound signals have been digitally encoded and transmitted in telephone switching systems.

In the conventional case, the waveforms of the audio signal and the audible sound signal were digitally encoded and transmitted without making any distinction between them. For this reason, the conventional encoding speed was as high as 64 bits. However, for example, by using a modem on a 926-Hz line with a band of 0.3 to 3.4 and transmitting bits to 926, the audio signal is transmitted to, for example, 2 or 4 bits:
Nowadays, consideration is being given to compressing the band to 2 or 4 bits and transmitting it over 4 lines, and if you try to compress the band to 2 or 4 bits and transmit it, the characteristic spectrum of the voice waveform will change from the voice to be transmitted. It is necessary to extract and encode. When such a band compression technique is used, monochromatic signals such as the above-mentioned ring tone and busy tone may be lost in the band compression circuit. The purpose of the present invention is to solve the above-mentioned problems, and the signal tone transmission system of the present invention is a signal tone transmission system that transmits voice signals and audible sound signals via an exchange. and a band compression circuit that compresses the band of the audio signal by using characteristic spectrum information extracted from the audio, digitizes the audio signal through the band compression circuit, and transmits the audio signal in the form of frame information on the line. a filter for separating and extracting the audible signal from the audio signal; and an audible signal encoding circuit for encoding the extracted audible signal into a predetermined code. The signal encoded by the audible signal encoding circuit is placed on the frame information and sent to the line, and the receiving side converts the audio signal or the audible signal based on the frame information. It is characterized by being designed to play.

This will be explained below with reference to the drawings. FIG. 1 shows the configuration of an embodiment of the transmitting side of the present invention, and FIG. 2 shows a frame format created by the frame format creation circuit shown in FIG.
An example of the format is shown.

In Fig. 1, 1 is a telephone set, 2 is a switchboard, 3 is an audible sound (including voice signal) input terminal, 4 is an SS input terminal, and 5 is a level adjuster that adjusts the signal level of audible sound including voice signals. 6 is an analog-to-digital converter that digitizes the audio signal, and 7 is a band compression circuit that converts the formant frequency, its amplitude, and the first formant and second formant from the given audio input. 8 is a busy sound extraction filter; 9 is a busy sound extraction filter; 1 is a busy tone detection/encoding circuit which notifies a frame format creation circuit (to be described later) of pattern "11" as explained with reference to FIG. 2 when a busy tone is detected; 10 is a calling circuit; Sound extraction filter, 1
1 is a ringing tone detection and encoding circuit, and when a ringing tone is detected, a pattern ``1'' is generated as explained with reference to FIG.
12 is a dial pulse detection circuit that notifies SS to a frame format creation circuit to be described later.
Detecting dial pulse from line input signal, 1
3 is a dial pulse encoding circuit which encodes the detected dial pulse and supplies it to the frame format generation circuit described later; 14 is a frame format generation circuit which encodes the detected dial pulse and supplies it to the above-mentioned band compression circuit 7; The frame information shown in FIG. 2 is created based on the output from the encoder and the output from each of the encoding circuits 9, 11, and 13 as described with reference to FIG.

Audible signals, including audio signals, are supplied to the output unit fabrication through the terminal 3 shown.

In the case of an audio signal, it is digitized by the converter 6, and spectrum information etc. are extracted and encoded by the band compression circuit 7.

When transmitting the audio signal, the frame format generating circuit 14 assigns logic "1" to the DP-TONE instruction bit shown in FIG. - It may be considered that the encoded audio signal described above is placed on the part. Note that the frame bits in the frame information shown in FIG.
” can be considered to be given alternately. When using the band compression circuit 7 that encodes the audio signal as described above,
If a busy tone of 400 Hz or a ring tone of 432 Hz is passed through the band compression circuit 7, each tone will be lost because each tone is monochromatic, that is, has a single frequency.

For this reason, in the case of the present invention, when a busy tone is given from the illustrated terminal 3, it is extracted by the filter 8, and the pattern "11" is converted into a frame format generating circuit by the encoding circuit 9. 14. Further, when a ring tone is given from the illustrated terminal 3, it is extracted by the filter 10, and the pattern "
10'' is supplied to the frame format creation circuit 14. In the frame format creation circuit 14 to which the pattern "11J" or "10" is notified, the DP-TONE instruction bit of the frame information shown in FIG. [11] or [10] is loaded onto the line and sent out on the line.

Further, when a dial pulse is supplied from the illustrated terminal 4, it is detected by the dial pulse detection circuit 12, and based on this result, the dial pulse encoding circuit 13
is encoded and notified to the frame format creation circuit 14.

In this case, the frame format creation circuit 14 sets the DP-TONE instruction bit of the frame information shown in FIG. It is configured to carry a pulse and send it out on the line. Although not shown in the diagram,
On the receiving side, when the above frame information is received,
After synchronizing with frame bit F, DP-T
Based on the contents of the ONE instruction bit, in the case of a voice signal, the original voice is reproduced from the above-mentioned formant and transmitted to the receiving telephone.

Also, based on the contents of the DP-TONE instruction bit, patterns such as "11", "10", "01", etc. in the frame information are identified in the case of a busy tone, ring tone, or dial pulse. Then, in the case of a busy tone, a 400Hz analog signal is generated, in the case of a ring tone, a 432Hz analog signal is generated, and in the case of a dial pulse, it is generated based on the content of the dial pulse part in the frame information. Generate dial pulse. The hook information shown in Figure 2 is the dial pulse detection circuit 12 shown in Figure 1.
Detection and determination are made in . As explained above, according to the present invention, it is possible to compress an audio signal to, for example, 2.4K bits using the band compression circuit 7 shown in FIG.
In addition, busy tones and ringing tones that are eliminated by passing through the band compression circuit 7 are separately encoded and notified to the frame format creation circuit 14. For this reason, it becomes possible to digitize and transmit an audible sound signal such as the busy tone to the receiving side without error.

[Brief explanation of the drawing]

FIG. 1 shows the configuration of an embodiment of the transmitting side of the present invention, and FIG. 2 shows an embodiment of a frame format created by the frame format creation circuit shown in FIG. In the figure, 1 is a telephone, 2 is a switchboard, 3 is an audible sound input terminal,
4 is the SS input terminal, 5 is the level adjuster, and 6 is the analog
Digital converter, 7 is a band compression circuit, 8 is a busy tone extraction filter, 9 is a busy tone detection and encoding circuit, 10 is a ringing tone extraction filter, 11 is a ringing tone detection and encoding circuit, 1
2 is a dial pulse detection circuit, 13 is a dial pulse encoding circuit, 13 is a dial pulse encoding circuit, 1
4 represents a frame format creation circuit.

Claims (1)

[Claims] 1 In a signal tone transmission system that transmits a voice signal and an audible sound signal via an exchange, the voice signal is supplied and the band is compressed by using characteristic spectrum information extracted from the voice. and is configured to digitize the audio signal via the band compression circuit and transmit it in the form of frame information on the line, and to separate the audible sound signal from the audio signal. It is equipped with a filter for extracting the audible sound signal and an audible sound signal encoding circuit for encoding the extracted audible sound signal into a predetermined code, and converts the signal encoded by the audible sound signal encoding circuit into the above-mentioned frame information. 1. A signal tone transmission system characterized in that the voice signal or the audible tone signal is transmitted on a line on a receiving side based on the frame information.