JPH04142129A - Signal transmitter and signal receiver - Google Patents

Abstract

PURPOSE:To transmit a main signal and a sub signal by using the transmission line of single channel and to improve transmission efficiency by providing a signal forming means for main transmission, a signal forming means for sub transmission, and a signal switching control means. CONSTITUTION:Error detection code attaching parts 12a, 12b which perform the generation and addition of error codes by different generating functions on each output of an audio encoder 11 and a signaling encoder 15a, and a switching circuit SW which selects the output of the attaching parts 12a, 12b according to a signaling flag and supplies it to a scrambling part 13 are provided. The main signal, after an arithmetic operation by a prescribed generating polynominal for error detection being performed when the sub signal remains unchanged, is outputted to the transmission line as a frame. When the sub signal is changed, the arithmetic operation is performed on the sub signal by the generating polynominal different from the above-mentioned generating polynominal, and is generated as the frame, and the frame is outputted to the transmission line instead of the main signal at that time. Thereby, it is possible to transmit the main signal and the sub signal via a single transmission line, and to improve the transmission efficiency.

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention relates to a signal transmitting device and a signal receiving device that efficiently transmit and receive two systems of signals having significantly different sign change rates. ``Prior Art'' A signal transmission system is known that transmits a main signal that is an encoded audio signal, and also transmits a lateral ring signal whose code change rate is significantly smaller than that of the main signal as a sub-signal. FIG. 4 shows an example of the configuration of this type of signal transmission system. In this figure, 10 is a signal transmitting device, 20 is a signal receiving device, and 31a and 32a are each a signal transmitting bag W11.
0 and the signal receiving device 120. The signal transmitting device 10 includes a voice transmitting system including a voice encoder 11, an error detection code adding section 12, a scrambling section 13, and a frame synchronization inserting section 14 connected in cascade, and a signaling transmitting system including a signaling encoder 15. The signal receiving device also includes an audio receiving system including a frame synchronization detection section 21, an unscrambling section 22, an error detection section 23, and an audio decoder 24, and a signaling decoder 25.
and a signaling reception system. In such a configuration, the audio signal to be transmitted is sequentially encoded by the audio encoder 11 in the signal transmitting device 10, assembled into audio frames of a predetermined length of time, and output. This audio frame is the error detection code addition part 1
2, each bit constituting the frame is subjected to calculation using a predetermined generating polynomial, and an error detection code based on the calculation result is added. Then, an information frame obtained by adding an error detection code to the audio frame is sent to the scrambler 13. Next, the scrambling unit 13 performs scrambling processing on the information frame using a predetermined generator polynomial, and outputs the information frame as an information frame that does not include a bit string having the same content as a frame synchronization bit, which will be described later. Then, by the frame synchronization insertion unit 14,
A frame synchronization bit of a predetermined bit length is added to the beginning of the scrambled information frame, and the transmission path 81
supplied to a. Further, a signaling signal representing a change in state on the transmitting side is encoded by the signaling encoder 25 at predetermined intervals and is supplied to the transmission path 31b. In the signal receiving device 20, a frame synchronization detection section 21
As a result, the frame synchronization bit in the received signal via the transmission path 31a is detected, and the subsequent information frame is extracted and output. This information frame is subjected to unscrambling processing corresponding to the scrambling processing in the signal transmitting device 10 by the unscrambling unit 22, and an information frame consisting of an error detection code and a voice frame is restored. Then, each bit of the audio frame is subjected to an operation by the error detection unit 23 using a generating polynomial corresponding to the generation of the error detection code in the signal transmitting device 1110. Based on this calculation result, it is determined whether there is an error in the received audio frame. If there is no error, the error detection code is deleted from the audio frame, the audio decoder 24 decodes the audio signal, and outputs the audio signal. Further, the received signal via the transmission path 31b is decoded by the signaling decoder 25 and output. ``Problems to be Solved by the Invention'' By the way, the conventional signal transmitting device and signal receiving device described above transmit a sub-signal whose sign change rate is much lower than that of the main signal, separately from the main signal transmission path. However, this method requires a sub-signal transmission path, and has a problem in that the transmission efficiency is extremely low. In order to solve this problem, when there is a change in the sub signal (signaling signal), a frame is created in which a predetermined identification flag is added to the sub signal after the change, and the main signal (audio signal) is added to the sub signal after the change. ) has been proposed, thereby transmitting both the main signal and the sub-signal over a single transmission path. However, in this method, a flag bit for signaling signal identification must be created within the frame, which requires complicated processing. Further, if there is an error in the transmission of the signaling identification flag bit, correct signaling information cannot be obtained. In order to avoid this, it is necessary to add an error detection code to the flag bit for signaling identification, resulting in the problem that more complicated processing is required. This invention was made in view of the above circumstances,
Provided is a signal transmitting device and a signal receiving device that can transmit a main signal and a sub-signal through a single transmission path and can detect transmission errors in the main signal and sub-signal with a simple configuration. The purpose is to "Means for Solving the Problem" The invention according to claim 1 transmits a main signal in which audio is encoded and a sub-signal whose code change probability is lower than that of the main signal through a single-channel transmission path. A main transmission signal forming means for transmitting to a partner device, the main transmission signal forming means performing an operation on the main signal using a predetermined generating polynomial for error detection and outputting the resultant as a main transmission signal; a sub-transmission signal forming means for performing an operation using a generating polynomial different from the generating polynomial in the main transmission signal forming means and outputting the resultant as a sub-transmission signal; The main transmission signal is supplied to the transmission line in a predetermined frame format, and the sub-transmission signal is discarded, and when a sign change occurs in the sub-signal, the sub-transmission signal is replaced with the main transmission signal. The present invention is characterized by comprising signal switching control means for switching and controlling output signals to the transmission path so that the same frame format is supplied to the transmission path and the main transmission signal is discarded. Further, the invention of claim 2 is a device that receives a main signal in which audio is encoded and a sub-signal whose code change probability is lower than that of the main signal from a partner device via a single-channel transmission path. a main signal error detection means for detecting an error for each frame by performing an operation using a main signal generator polynomial on the received signal obtained from the transmission path; sub-signal error detection means for detecting errors for each frame by performing calculations using the sub-signal generation polynomial that is different from the sub-signal generation polynomial; and no errors are detected by the main signal error detection means, and When an error is detected by the sub-signal error detection means, the received signal frame is output as a main reception signal frame, and when the error is detected by the main signal error detection means and the sub-signal error detection means When no error is detected by the error detection means, the frame of the received signal is output as a frame of the sub-reception signal, and the main reception signal at that time is determined based on the frame output as the main reception signal before that point in time. The present invention is characterized by comprising a signal switching M control means for switching and controlling the reception of the received signal from the transmission path so as to output a frame corresponding to the received signal from the transmission path. "Operation" According to the invention of claim 1, when the sub-signal does not change, the main signal is subjected to calculation using a predetermined generating polynomial for error detection and is output as a frame to the transmission path. When the sub-signal changes, the sub-signal is subjected to an operation using a generating polynomial different from the above-mentioned generating polynomial to create a frame, and this frame is output to the transmission path in place of the frame of the main signal at that point in time. . According to the invention of claim 2, each error detection corresponding to each generation polynomial corresponding to each of the main signal and the sub signal is performed on the frame received via the transmission path, and the received frame is It is determined that the frame corresponds to the generating polynomial that was not detected, and the signal corresponding to the determination result is outputted among the main signal and the sub signal. "Embodiments" Hereinafter, the present invention will be described in detail with reference to the drawings.

[First Embodiment] FIG. 1 shows a signal transmitting device 10 according to a first embodiment of the present invention.
The configuration of a transmission system using a signal receiving device 110b and a signal receiving device 110b is shown. Signal transmitting device 10a and signal receiving device 1
10b is connected via a single channel transmission line 31, and sends and receives audio signals and signaling signals via this transmission line 31. In this figure, parts corresponding to those in FIG. 4 described above are designated by the same reference numerals, and their explanations will be omitted. The signal transmission bag W10a replaces the signaling encoder 15 and error detection code adding section 12 in FIG.
A signaling encoder 15a1 that encodes and outputs the changed signaling signal and asserts the signaling flag 5FLG only when the signaling signal to be transmitted changes; The outputs of the error detection code addition units 12a and 12b, which generate and add error detection codes using the generated polynomials, and the error detection code addition units 12a and 12b are selected according to the signaling flag 5FLG, and are supplied to the scrambling unit 13. A switch circuit SW is provided. Furthermore, instead of the error check section 23, audio decoder 24, and signaling decoder 25 in FIG. Error detection units 23a and 23b perform transmission error detection corresponding to the generator polynomial; an audio decoder 24a1 and an error detection unit 23b perform decoding of the received information frame into an audio signal based on the transmission error detection result of the error detection unit 23a; A signaling decoder 25a is provided which decodes the received information frame into a signaling signal based on the transmission error detection result. Here, the audio decoder 24a has a buffer with a capacity equivalent to at least one frame for storing received information frames, and the error detection unit 23a has a buffer with a capacity equivalent to at least one frame.
When a transmission error is detected, the previous frame stored in this buffer is demodulated and output (that is, the previous value holding operation) is performed. The time chart shown in FIG. 2 shows an example of the operation of the signal transmission system shown in FIG. The operation of the signal transmission system shown in FIG. 1 will be explained below with reference to this time chart. The audio signal to be transmitted is encoded by the audio encoder 11 in units of frame period T, and is divided into audio frames Act, Ac.
t, - are sequentially output serially (Figure 2 (a)
reference). Audio frame A C,. A Cl+- is sequentially added to the error detection code adding section 12a.
The error detection codes Eat, Eam+- to be added to each audio frame ACl+AC*,- are generated by calculation using a predetermined generating polynomial A. Then, a series of information frames (ACl, E
al), (Act, E at). are sequentially output (see FIG. 2(b)). On the other hand, the signaling encoder 15a encodes the changed signaling signal and outputs the signaling frame SC only when the signaling signal to be transmitted changes. In this example, the signaling signal changes in the second frame period, and the signaling frame SC1 in which the changed signaling signal is encoded is output from the signaling encoder 15 in the third frame period. (See Figure 2 (C)). Also, the period during which the signaling frame is output (in this example, the third
During the frame output period), the signaling flag 5FLG
is set to "1", and during other periods, the signaling flag 5FLG is set to "O@" (see FIG. 2(e)). A calculation is performed using a different generating polynomial B, and an error detection code Eb based on the calculation result is added and output (Fig. 2 (d)). During the period when the signaling flag 5FLG is 10'', an error is detected. The output of the error detection section 12a is selected by the switch circuit SW and outputted as the information frame Is, and during the period of 1", the output of the error detection section 12b is selected and outputted as the information frame Is. Therefore, in this example, , as an information frame IS from the switch circuit SW, (A C
t, E at) (Act, Eat), (SCm, Eb
m), (AC,, Ea,), - are output sequentially (second
(See figure (f)). Each of these information frames IS is subjected to scrambling processing by the scrambling unit 13,
A frame synchronization bit 5YNC is added to the beginning of each scrambled information frame by the frame synchronization insertion section 14, and the information frames are sequentially output to the transmission path 31 as a transmission frame F (see FIG. 2(g)). In the signal receiving device t20a, the frame synchronization detecting section 22 detects a frame synchronization bit in the received signal via the transmission path 31, and extracts the following information frame IR'. Each information frame IR' is descrambled by the unscrambler 22, and the final information frame IR is sequentially restored (see FIG. 2(h)). In the error detection section 23a, error detection is performed on the information frame IR based on the generating polynomial A described above. Further, in the error detection unit 23b, the information frame IR
Error detection is performed based on the generator polynomial B. In this example, only the third information frame IR includes the error detection code Eb based on the generator polynomial B, and the other information frames 1, 2, 4, - are Error detection code using the above generator polynomial A”
a mo E a In E a 4°-. Therefore, the error detection unit 23a determines that there is an error in the third frame and outputs the error signal ERa. - for each frame, the error detection section 23b determines that there is an error and outputs an error signal ERb (see FIG. 2(j)). On the other hand, each information frame IR is taken into the audio decoder 24a and the signaling decoder 25a. In the audio decoder 24a, the captured information frame IR is stored in a buffer for a predetermined frame period. Error signal ERa
is not generated, the audio decoder 24a outputs the information frame IR taken into the buffer in the frame period.
The audio frames at are decoded in the subsequent frame period and output as received audio signals (in this example, the audio frames Act, ACI AC-, AC, -
). Furthermore, when the error signal ERa is generated, the audio frame of the information frame JR taken into the buffer before the cycle of the relevant frame (in this case, the audio frame A
Cm) is decoded and output as a received audio signal (see FIG. 2(k)). In this way, the reception of voice frames may be interrupted due to the insertion of a signaling frame, but the degree of occurrence is extremely small, and the frame period is usually sufficiently short, and the voice caused by the voice frame received immediately before is interrupted. Since playback is performed, there is no problem with audio reception. In the signaling decoder 25a, since the error signal ERb for the third captured information frame IR is not generated, it is determined that this information frame has a signaling frame, and the signaling frame SC1 is decoded, and the received signaling A signal is output (see FIG. 2 (1)). In the example explained above, when a voice frame cannot be received due to the insertion of a signaling frame, the received and voice signals are decoded by the previous value holding operation. By performing interpolation calculations and reproducing missing audio frames, even higher quality audio transmission can be achieved. [Second Embodiment 1] FIG. 3 shows a signal transmitting device 1 according to a second embodiment of the present invention.
FIG. 2 is a configuration diagram of a signal transmission system using a signal receiving device 20b and a signal receiving device 20b. In this figure, parts corresponding to those in FIG. 1 described above are designated by the same reference numerals, and their explanation will be omitted. In the signal receiving device 10b, error detection code adding units 12c and 12d add error detection codes using a common generating polynomial to audio frames and signaling frames. However, the scrambler 13
Scrambling processing using different generating polynomials C and D is performed by c and 13d. In the signal receiving device 20b, the unscrambling units 22c and 22d perform unscrambling processing corresponding to the generating polynomials C and D, and the error detecting unit 23c
and 23d, the error detection code adding section 12c
and 12d, error detection corresponding to the common generating polynomial is performed. In other words, this signal transmitting device 10b and signal receiving bag!
20b uses a common generator polynomial for generating an error detection code for voice frames and signaling frames, and changes the generator polynomial for scrambling between voice frames and signaling frames, thereby making it possible to identify frames on the receiving side. It is something to do. Even with this configuration, the same effects as in the first embodiment can be obtained. [Effects of the Invention] As described above, according to the present invention, it is possible to transmit the main signal and the sub-signal using a single channel transmission path, and it is possible to obtain the effect that the transmission efficiency is improved. Further, since error detection is performed on both the main signal and the sub signal, there is an effect that high quality signal transmission is performed.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 shows a signal transmitting device according to a first embodiment of the present invention.
10a and a signal transmission system using a signal receiving device 20a, FIG. 2 is a time chart showing the operation of the same embodiment, and FIG. 3 is a signal transmitting device 10b and a signal receiving device according to a second embodiment of the present invention. A configuration diagram of a signal transmission system using the device 20b, FIG. 4 shows the conventional signal transmission device 1.
FIG. 2 is a configuration diagram of a signal transmission system using 0 and a signal receiving device 20. 11--Speech encoder, 15a--Signaling encoder,
12a, 12b--error detection code addition section, 5W--
Switch circuit, 23a, 23b--error detection section, 24
a-1 audio decoder, 25a-1 signaling decoder.

Claims (2)

[Claims] (1) A device that transmits a main signal in which audio is encoded and a sub-signal whose code change probability is lower than that of the main signal to a partner device via a single-channel transmission path, the main signal being a main transmission signal forming means for performing an operation using a predetermined generating polynomial for error detection and outputting the resultant as a main transmission signal; a sub-transmission signal forming means for performing an operation using a generating polynomial and outputting the sub-transmission signal as a sub-transmission signal; and when no sign change occurs in the sub-signal, converting the main transmission signal into a predetermined frame format and converting the main transmission signal into the transmission path. When a sign change occurs in the sub-signal, the sub-transmission signal is supplied to the transmission line in the same frame format as the main transmission signal, and the sub-transmission signal is discarded. The main transmission signal should be discarded.
A signal transmitting device comprising: signal switching control means for switching and controlling output signals to the transmission path. (2) A device that receives a main signal in which audio is encoded and a sub-signal whose code change probability is lower than that of the main signal from a partner device via a single-channel transmission path, the transmission path being Main signal error detection means performs an operation using a main signal generating polynomial on the received signal obtained from the transmission line to detect errors for each frame; and the main signal generating polynomial on the received signal obtained from the transmission path. sub-signal error detection means for detecting errors for each frame by performing calculations using different sub-signal generating polynomials; and sub-signal error detection means in which no errors are detected by the main-signal error detection means; When an error is detected by the means, the frame of the received signal is output as a frame of the main reception signal, the error is detected by the main signal error detection means, and the error is detected by the sub signal error detection means. When it is not detected, the frame of the received signal is output as a frame of the sub-reception signal, and at the same time, as the main reception signal, a frame determined based on the frame outputted as the main reception signal before that time is output. A signal receiving device comprising: signal switching control means for switching and controlling the reception of the received signal from the transmission path.