JPH01316056A - Signaling transmission system - 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] [Summary of the Invention] An object of the present invention is to solve the problem of modem signal quality deterioration in in-slot signaling transmission regarding a signaling transmission method in which a signaling signal is inserted and transmitted by bit stealing into an audio/modem signal. The purpose is to determine whether an input signal is a voice signal or a modem signal in a signaling transmission method in a communication system in which voice signals and modem signals can be transmitted with band compression, and signaling data is transmitted by inserting bit steals into these signals. Then, based on the output signals (St, Sz) as a result of the determination, bit stealing is stopped in the case of a modem signal.

[Industrial application field]

The present invention relates to a signaling transmission method that inserts a signaling signal into a voice/modem signal using bit stealing and transmits the signal.

The audio signal is sampled, each sample is digitized and transmitted, and at this time, signaling data such as dial pulses are periodically replaced (bit stolen) with the LSB of the digital value of each sample (slot), and thus 1
There is a method for transmitting audio signals and signaling data over a real transmission path.

The present invention relates to such an in-slot signaling transmission system.

[Conventional technology]

Even if each sample of the audio signal is converted into, for example, 8-bit digital data and the LSB thereof is replaced with signaling data at a cycle of IKHz, the quality of the audio signal will not deteriorate so much.

Also, 64 Kbps (8-bit digital data above)
There is also a method that compresses the signal to 32 Kbps and transmits it. In this case, the LSB of the 4-bit digital data is bit-stealed with signaling data, but even with this, the sound quality is such that if the signal is an audio signal, it will be harsh. No deterioration occurs. However, if the above-mentioned signal is a modem (FAX) signal, bit stealing of the 4 LSBs causes a noticeable deterioration in image quality. In particular, when transmitting through multiple exchanges, the image quality deteriorates in proportion to the number of relay exchanges, resulting in a significant difference in image quality between the transmitting end and the receiving end.

[One problem to be solved by the invention] In corporate networks, 64 Kbps signals are band-compressed to 32 Kbps to make the transmission path more efficient. There is a need to enable multi-stage relay exchange transmission while suppressing signal quality deterioration.

In the conventional signaling bit stealing method, the signaling bit is stolen even after the transmission of the telephone on/off footer signal and dialed number is completed, that is, even during voice call/FAX communication. For this reason, particularly in the transmission of modem signals, data is periodically dropped, and as the number of relay exchanges increases, the image quality deteriorates.

The present invention aims to improve this point and solve the problem of modem signal quality deterioration in in-slot signaling transmission.

[Means to solve the problem]

FIG. 1 is a diagram illustrating the principle of the present invention. Reference numeral 11 denotes a coder part of a voice band compression encoding device, which converts an input signal of, for example, 64 Kbps into a code of 32 Kbps. 12 is a decoder section which inversely transforms the coder part 1; Sl.

S2 is the output signal of the voice/modem judgment result of the input signal, C, , C2 is the bit steal clock CLK,...
This is a control gate based on the judgment output signals S, , S2 of CLK2.

[Function] In this configuration, when the input signal is an audio signal, the judgment output signal S,, S2 is at H level, and when it is a modem signal (FAX (No. i)), it is at L level.
z, 02 opens and bit steal clock CLK+
, CLK2 are input to the coder section 10 and the decoder section 20, and in the modem signal, the gates G, , G2 are closed and the clock is not input, so that bit stealing is not performed.

In this way, bit stealing during modem signal transmission after the telephone line is established can be prevented, and quality deterioration of the modem signal can be prevented.

〔Example〕

FIG. 2 shows an embodiment of the present invention. The coder part 10 is an optimal algorithm block 11 for band compression of audio signals.
, an optimal algorithm block 12 for band compression of modem signals, switch sections 13, 14 . Block 1 that determines whether the input signal is an audio signal or a modem signal
5, control gate Gl (SS signal MUX section)
has an AND gate Ga to which the bit steal clock CLK and the transmission signaling signal SS are input, and an AND gate cb to which the output of the gate Ga and the determination output signal S are input.

The decoder section 20 has the same configuration as the coder section 10, and includes a voice optimization algorithm block 21, a modem optimization algorithm block 22, switch sections 23 and 24, and an input signal determination block 25. The control gate G2 (SR multiplied signal DMU section) is an ant game) Gc in which the bit steal clock CL Kz and the judgment output signal S2 are manually input, an AND gate Gd into which the output of the gate Gc and a human input signal to the decoder section 20 are input, and the output of the gate Cd and the judgment output S
2 input or game) has Ge.

If the input signal is an audio signal, the coder part 100 judgment block 15 outputs an H level signal S1, which is sent to the gate cb.
At the same time as opening, the switch units 13 and 14 are switched to the audio optimization algorithm block 11 side (the initial state is set to the 11 side, so there is no change in details). Therefore, the input audio signal is band-compressed by the algorithm of block 11 and is reduced to 64 Kb.
ps is converted to 32K bps and output. Also, since the gate cb is opened, the signaling data SS is input to the block 11 at the timing of the clock CLKI, and is replaced with the 4-bit data USB as described above (bit stealing is performed).

If the input signal is a modem signal, the determination block 15 outputs an L level signal S1, which closes the gate Gb and switches the switch sections 13, 14 to the modem optimization algorithm block 12 side.

Therefore, the input modem signal is bandwidth compressed by the algorithm of block 12, and the 64 Kbps becomes 32 Kbps and is output. Since gate Gb is closed, bit stealing is not performed.

In the decoder 20, if the signal sent from the coder section 10 is an audio signal, the determination block 25 outputs a signal S2 of H level, which opens the gate Gc and switches the switch section 23.
24 to the audio optimization algorithm block 21 side. Therefore, the 32 Kbps audio signal input to the decoder section 20 is converted into 64 Kbps by the algorithm of block 21.
The signal is converted back to the audio signal of s and output. Also, the gate Gc is opened and the bit steal clock CLKz is connected to the gate Gc.
, which opens gate Gd to extract signaling data from the input audio signal. This is orgate Ge
The received signaling signal SR is outputted through the receiving signal SR. Further, CLK that has come out of gate Gc enters block 21 to remove signaling data (all 0s or 1s).

If the input signal is a modem signal, the judgment block 25 sends an L level signal S2, which enters the gate Gc to close the gate and enters the switch section 23, 24 to pass them to the modem optimization algorithm block 22. Switch. Therefore, the input modem signal of 32Kbps is block 2.
2 is converted back to a 64 Kbps modem signal and output.

Since the gate Gc is closed and the clock CLKz is not output from the gate, the LSB of the audio signal is not changed or taken out, and the received signaling signal SR becomes the signal S2.
is inverted and kept at a constant H level.

The signaling signal during a call (communication) indicates the line make state and is constant, so the signal S2 can be used instead as described above. When the communication of the modem signal is completed, the output signal SI+S2 of the decision block 15.2'5 returns to the H level.
Therefore, the normal bi-nod steal transmission mode is restored. The calling party's or called party's on-footer signal is transmitted with bit stealth to allow the call to be terminated.

FIG. 3(a) shows the bit steel mode. 1.2 and 3.4 of the data on the transmission path indicate data bits, and 1
MS13,4 is LSB. Since it is compressed to 32 Kbps, one sample is 4 bits. This LS
B4 is replaced with a transmission signaling signal SS using the IKHz bit steal clock CLK.

The human signal determination block can perform voice/FAXlli classification using training patterns. G
There is a training pattern in front of the IIIFAX image data, and for example, as shown in Figure 3(b), this includes segment 1 lasting approximately 20 m5, segment 2 lasting approximately 53 m5, segment 3 lasting approximately 160 mS, and segment 4 lasting approximately 20 m5. Consisting of

There is no signal transmitted in segment 1, and segment 2
, an alternating pattern, segment 3 an equalizer adjustment pattern, and segment 4 the result of scrambling all data 1's. The signal corresponding to the alternating pattern section of segment 2 is a completely repeating waveform, with a frequency of 500 Hz,
It becomes a composite sine wave of 1700Hz and 2900Hz. By using this, it is possible to identify voice/FAX.

FIG. 3(C) shows a decision block of this type. 31 is a band pass filter (BPF) that extracts 1700Hz,
33 is a carrier component detector using PLL. B.P.
In response to the output of F31, a clock of 1700 Hz is generated by PTT-, which is used for synchronous detection. By not causing a sign change in the detected output for a certain period of time, segment 2, and eventually the training output, is detected. Furthermore, in order to distinguish it from a single sine wave of 1700 Hz, a 2900 Hz BPF 32 is used, and the result of integrating its output with an integrator 35 and the result of directly integrating the input signal with an integrator 34 are used, and the results are integrated with a comparator 36. This improves the accuracy of training signal detection. It is assumed that all the signals from the detector 33 and integrators 34 and 35 are present as modem signals and the output signal S is positive, and those that are absent are audio signals and the output signal S is high. When the communication ends, there is no input to the comparator 36, and the output signal S becomes H, and this audio signal detection state is the initial state of this circuit.

〔Effect of the invention〕

As explained above, according to the present invention, bit stealing is prohibited during modem (FAX) signal communication, which enables multi-stage exchange relaying in corporate networks, etc., without degrading the quality of modem data. Become.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the principle of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is an explanatory diagram of the configuration and operation of each part. In Fig. 1, 10 is a coder part, 20 is a decoder part, and S +
, S2 is the voice/modem, the output signal of the discrimination result, C
L Kl+ CL Kz is a clock for bit stealing, and G + and G z are control gates thereof.

Claims (1)

[Claims] 1. In a signaling transmission method in a communication system in which voice signals and modem signals can be transmitted by compressing the band, and signaling data is inserted into these signals by bit stealing and transmitted, whether the input signal is a voice signal or not. A signaling transmission method characterized in that it determines whether it is a modem signal and stops bit stealing in the case of a modem signal based on output signals (S_1, S_2) as a result of the determination.