JPH0666751B2 - Signaling signal transmitter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to a voice line signaling signal suitable for a transmission apparatus that mixes low-speed data signals of various speeds and voice signals and multiplex-transmits them on a high-speed digital line. TECHNICAL FIELD The present invention relates to a signaling signal transmission device for transmission.

"Conventional technology" Conventionally, when digitizing and transmitting audio signals, a PC
It is most common to M-encode and transmit as a 64 kb / s digital signal. For transmitting a signaling signal of a voice line, for example, in the PCM24 system, P of 64 kb / s is used.
1.54 with 24 CM-encoded digital voice signals
8M in 1 frame by combining multi-frame in 4Mb / s
A so-called in-channel signaling system is adopted in which the least significant bit of the PCM code of the bits is periodically bit-steeled and a signaling signal is superimposed and transmitted.

In the PCM30 system, a 64 kb / s channel (8 bits in one frame) for transmitting a signaling signal within 2.048 Mb / s is defined, and a so-called out-channel signaling signal transmission system is adopted. .

The above in-channel method is 32 kb / s, 16 kb / s, 8 kb
Since the voice information is sufficiently compressed in the transmission of a high-efficiency coded voice signal of 1 / s, even if one bit is bit-steeled, the quality is greatly deteriorated and it is not suitable for the transmission of the high-efficiency coded voice. There is.

Further, in the above-mentioned conventional out-channel method, since the signaling frame is configured in units of 64 kb / s, that is, since the signaling signal is assigned in units of one channel (8 bits) in one frame, If the number of channels is small, many bits have already been allocated for signaling signals and transmission efficiency is poor,
Furthermore, high-efficiency coded speech, which will become the mainstream in the future, and 8 kb /
It has a drawback that it is not suitable for mixed transmission with a data signal having an s-system bearer speed.

32kb / s ADPCM (adaptive differential PCM, CCITT recommendation) is used as a method for encoding audio signals and converting them into digital audio signals.
G.721) and 16 kb / s encoding are APC-AB
As (adaptive prediction adaptive bit allocation coding) system and 8 kb / s coding, ATC-VQ (adaptive transform vector coding) system, MPC (multi-pulse coding) system and the like are known.

On the other hand, as a method for converting low-speed data into an 8 kb / s series digital signal, there is, for example, the CCITT recommended I.460 signal speed conversion method. By using 8 kb / s as a multi-frame configuration, 600 b / s, 2400 b / s and 4800 b / s are 8 kb
/ S, the speed conversion of 9600 b / s to 16 kb / s is performed.

Therefore, when a digital voice signal whose bearer speed is an integral multiple of 8 kb / s is time-division multiplexed and transmitted, or when the bearer speed is
8 kb / s integer multiple digital voice signal and bearer speed 8
When a data signal having an integral multiple of kb / s is time-division multiplexed and transmitted, it is considered most efficient to time-division multiplex the signaling signal in units of 8 kb / s.

"Means for Solving Problems" In the present invention, the input audio signal is 8 p
kb / s (p is a positive integer) is converted into a digital voice signal with a bearer speed, and the digital voice signals from at least a plurality of voice signal conversion streams are transmitted at the frame length 1 /
Assuming a transmission device that performs time division multiplexing on a bit-by-bit basis in a multi-frame structure at 8 kHz, signaling signals for a plurality of lines of an input voice signal are transmitted at 8 kb / s at a signaling conversion unit.
Bearer rate multiplexed signaling signal, and each bit of the multiplexed signaling signal is sequentially inserted into the specific time slot of each frame by one bit in the multiplex conversion unit to obtain a digital voice signal or the like. It is time-division multiplexed and transmitted.

In the multiplex conversion unit, a data signal having a bearer speed of an integral multiple of 8 kb / s may be multiplexed.

[Examples] Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. Audio signal 1-1 to 1-n
Bearer rates of 32 kb / s, 16 kb / s, and 8 kb / s depending on the acceptable coding quality and available transmission bandwidth.
To any of the digital audio signals of the audio signal converter 2-1
~ 2-n are converted respectively. 0.4kb / s, 0.8kb / s, ...,
Low-speed data signals 3-1 to 3-m of 2.4 kb / s and 4.8 kb / s are output as data signals of 8 kb / s bearer speed composed of multiple frames in the data signal converters 4-1 to 4-m. It

In the present invention, the signaling signals 5-1 to 5-n for n lines of the audio signals 1-1 to 1-n are transmitted by the signaling conversion unit 11 to the frame bit F of 1 bit, the status bit S of 1 bit and the signaling of n bit. One frame is composed of (n + 2) bits and is converted into a multiplexed signaling signal of 8 kb / s bearer rate. This multiplexed signaling signal will be repeated in (n + 2) frames in the multiplexed signal 14. The status bit S is a status notification signal for distinguishing the communication status / non-communication status of the voice line in the multiplexing unit. For example, when a failure occurs in the multiplexing device, the communication incompatibility state is transmitted to the opposing device through the status bit and used for suppressing the line connection control.

Data signal from the audio signal converters 2-1 to 2-n and digital audio signals 6-1 to 6-n with different or same encoding speeds and data signal converters 4-1 to 4-m 7-1 to 7-m and the multiplexed signaling signal 12 from the signaling conversion unit 11 are time-division multiplexed in bit units for each frame in the multiplexing conversion unit 13 and transmitted as a multiplexed signal 14. Incidentally, in FIG. 1, the description of the circuit on the receiving side is omitted.

As shown in FIG. 2A, the multiplexed signal from the multiplex converter 13 is, for example, the first to n + 2th frames as multiframes,
Each frame length T is 1/8000 second. Each frame is first
As shown in FIG. 2B by enlarging the frame, one bit of the multiplexed signaling signal 12 is transferred to the next one time slot, that is, the second time slot, in the specific one time slot, in this example, the first time slot. 1 bit of the 8 kb / s digital voice signal 6-1 in the next 2 time slots, that is, 2 bits of the 16 kb / s digital voice signal 6-2 in the 3rd and 4th time slots, in the next 4 time slots. 3
The 2 kb / s digital audio signal 6-3 is multiplexed with the n-channel digital audio signal bit by bit such that 2 bits of the 16 kb / s digital audio signal 6-4 is transmitted in the next 2 time slots. Subsequently, the data signals 7-1 to 7-m with a bearer rate of 8 kb / s are bit multiplexed in which only one bit is inserted in one time slot.

Each one bit is assigned to one time slot and multiplexed.

As shown in FIG. 2C, the multiplexed signaling signal 12 is preceded by the frame synchronization bit F and then the signaling signals 5-1, 5-.
2 ..., 5-n are arranged one bit at a time, each bit has one frame length T, and a status bit S of 1 bit is further inserted in the middle of the (n + 2) frame, so that (n + 2) as a whole.
A multiplexed frame having a frame length is configured, and the frame length is the same as the multiframe length of the multiplex conversion unit 13. Each bit of this multiplexed signaling signal is 8kb /
s bearer speed. This multiplexed signaling signal 12
Is assigned to the particular time slot of each (n + 2) frames of the multiplexed signal 14 by one bit, the first of which in this example.
It is inserted in each time slot. When the speed of the signaling signals 5-1 to 5-n is 400 b / s and n = 18, the multiplexed signaling signal 12 is as shown in FIG. 2D.

FIG. 3 shows a configuration example of the signaling conversion unit 11. That is, the n-line signaling signals 5-1 to 5-n of the voice signal are converted into logical levels by the level converting circuits 8-1 to 8-n, respectively, and the (n + 2) -bit signaling multi-frame converting circuit 15 inputs the signals. Input to terminals D1 to Dn. The signaling multiframe conversion circuit 15 responds to the frame synchronization bit F and the n-line signaling signals 5-1 to 5-n shown in FIG. 2C by the control clock 17 supplied from the multiframe assembling / disassembling clock generating circuit 16. A (n + 2) -bit frame composed of an n-bit signaling signal and a status bit S is assembled and output as a multiplexed signaling signal 12 of 8 kb / s bearer rate.

As a signaling signal transmission speed, it is necessary to secure 270 b / s or more necessary for transmitting a DP (dial pulse) signal used in a PBX (private branch exchange) or the like.

The multi-frame assembling / disassembling clock generation circuit 16 outputs control clocks 17 and 19 according to a bearer speed control signal 18 supplied from the outside. When n = 18, the signaling signals 5-1 to 5-n are converted at a sampling rate of 400 Hz, and the signaling signals for 18 lines are transmitted by a bearer signal of 8 kb / s as shown in Fig. 2D. You can On the other hand, when PBXs are connected in multiple stages and the transmission distortion of signaling signals accumulates and deteriorates the transmission quality of signaling signals, it is necessary to reduce the signal conversion distortion by increasing the sampling rate to 800 Hz. -1
As shown in FIG. 2E, a signaling signal for n / 2 (= 9) lines is transmitted with a bearer signal of 8 kb / s, with a sampling rate of ˜5-n set to 800 Hz. The sampling rate of the signaling signal is determined by the distortion distribution of the signaling signal.

On the other hand, a similar output from the other side output from the multiplex conversion unit 13
The 8 kb / s bearer rate multiplexed signaling signal 21 is input to the shift register 22 by the control clock 19 supplied from the multi-frame assembling / disassembling clock generation circuit 16 and output from the shift register 22 in parallel. The n-bit data signal output from the shift register 22 is latched in each of the latch circuits 23 by a clock obtained by dividing the control clock 19 by 1 / (n + 2), and the n-bit parallel outputs are level conversion circuits 9-1 to 9-9. Each is converted to a signal level by -n and output as signaling signals 10-1 to 10-n.

[Advantages of the Invention] As described above, in the present invention, the signaling signals 5-1 to 5-n for n lines of the speech signal are coded speech signals 6-1 to 6 in units of 8 kb / s bearer rate. -n, if needed 8kb
/ S Bearer speed data signals 7-1 to 7-m If converted to the same bearer speed and multiplexed for transmission, the signaling signal of the voice line is a voice signal with a different coding rate, and if necessary, a data signal. There is an effect that it can be multiplexed and transmitted by the same multiplexer. Furthermore, since the signal capacity of 8 kb / s corresponds to 1 bit of the transmission frame of a high-speed digital line, which is the minimum signal capacity, it is said that the signaling signal can be most efficiently multiplexed with the digital voice signal and the data signal and transmitted. effective.

Note that the multiplexing in the multiplex conversion unit 13 may be performed only for the digital voice signal and the multiplexed signaling signal. The multiplexing of the multiplexed signaling signal with the digital voice signal is not limited to the first time slot of one frame, and may be performed in any predetermined time slot. If there are many voice lines, a plurality of time slots in one frame may be used.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a frame configuration of a multiplexed signal 14, a configuration of each frame thereof, and an example of a frame configuration of a multiplexed signaling signal 12, and FIG. The figure is a block diagram showing a configuration example of a signaling conversion unit.

Claims (1)

[Claims] 1. A plurality of audio signal conversion units for converting an input audio signal into a digital audio signal having a bearer rate of 8 pkb / s (p is a positive integer), and a digital audio signal from at least the plurality of audio signal conversion units. And a multiplex converter for time-division-multiplexing each frame of a multi-frame composed of a plurality of frames each having a frame length of 1 / (8 kHz), wherein a plurality of lines of the input voice signal are provided. Minute signaling signal is multiplexed into a multiplexed signaling signal having a bearer rate of 8 kb / s, and a signaling conversion unit for supplying the multiplexed signal to the above-mentioned multiplex conversion unit is provided, and each bit of the multiplexed signaling signal from the signaling conversion unit is added to the above multiplex signal. One bit each is sequentially inserted into a specific time slot of each frame of the frame, and at least the digital signal from the audio conversion section is inserted. Signaling signal transmission apparatus characterized by multiplexing and transmitting in the voice signal and bits.