JP3024132B2 - Data transmission equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission apparatus, and more particularly, to a data transmission apparatus capable of extending the number of bits of one word of an existing transmission format and transmitting the same.

[Summary of the Invention]

The present invention is based on the existing transmission format of 1-bit m-bit (m is a positive integer) digital data by extending n-bit (n is a positive integer) lower-order data to the lower side of the m-bit data. In a data transmission apparatus for transmitting word (m + n) -bit digital data,
As a synthesizing method for multi-value synthesis of the digital data of bits and the digital data of lower n bits, by reading the digital data of upper m bits at the time of low resolution reproduction of the synthesized signal, This enables one-word bit expansion while ensuring compatibility with the conventional one-word m-bit transmission format.

[Conventional technology]

As signals for transmitting (including recording and reproducing) digital signals, those in the form of so-called binary signals are often used, and the transmission of multi-level signals of three or more values is relatively small at present. . However, in recent years, the transmission technology (including recording / reproduction technology) has been remarkably advanced and developed. In many cases, multi-valued signal transmission of three or more values has become possible, even though the binary signal transmission was limited in the past. I have.

In addition, there is a case where a request for partially expanding a function of a conventionally used transmission format (including a recording format) in accordance with advancement and development of technology sometimes arises. Can be considered. For example, when it is desired to expand the dynamic range by extending the number of bits of one word of the PCM audio signal, it is conceivable to change the transmission of the binary signal to the transmission of a multi-level signal of three or more values.

[Problems to be solved by the invention]

By the way, it is important to consider the compatibility with the conventionally used devices and media even if the information amount of the transmission signal has a margin according to the advancement and development of the technology as described above.

For example, even if a multi-level signal recording of three or more values can be recorded on an optical disc of a predetermined recording format in which binary signal recording has been conventionally performed, a conventional optical disc or a conventional optical disc recorded in accordance with the predetermined recording format can be used. If compatibility with conventional recording / reproducing devices cannot be obtained, these conventional optical disks and their recording / reproducing devices cannot be effectively used, resulting in large economic loss.

Here, the multi-value recording / reproducing technology is described in, for example,
Although it is disclosed in Japanese Patent Application Laid-Open No. 52-84717, there is no known technique for multi-leveling a signal to extend the number of bits of one word of data and considering compatibility with the related art.

The present invention has been made in view of such circumstances, and with the bit expansion of digital data, the signal transmission (including recording / reproduction) format has been changed from, for example, a binary signal format to a multi-level signal transmission format of three or more values. When evolved,
It is an object of the present invention to provide a data transmission device capable of easily achieving compatibility with a conventional binary signal format.

[Means for solving the problem]

The data transmission apparatus according to the present invention separates digital data of N bits (N is a positive integer) in one word into upper m bits (m is a positive integer and N> m) and lower (N−m) bits. Separating means, upper recording signal forming means for extracting a signal representing the value of each bit of the upper m bits, and lower recording signal forming means for extracting a signal representing the value of each bit of the lower (Nm) bits For each of the signals output from the upper recording signal forming means and the lower recording signal forming means, the amplitude of the upper bit signal is made larger than the amplitude of the lower bit signal, and And a multi-level synthesizing means for multi-leveling by synthesizing, and transmitting the multi-level signal synthesized by the multi-level synthesizing means.

[Operation] When a signal obtained by multi-valued synthesis of 1-bit N-bit digital data is reproduced at a low resolution, digital data of an existing transmission format of 1-word m-bit can be obtained. The number of bits of one word can be extended while maintaining compatibility with.

〔Example〕

FIG. 1 is a block diagram showing one embodiment of a data transmission device according to the present invention. In this case, the basic format of data transmission is, for example, 8 bits per word in a binary signal transmission (recording / reproducing) mode. By adopting a quaternary signal transmission mode, the lower 8 bits of each word are used. An extended transmission format of 16 bits per word to which lower bits of data are added is obtained.

In FIG. 1, for example, an analog audio signal or the like is input to an input terminal 1. This analog input signal is sampled by a sampling circuit 2 at a frequency of, for example, 32 kHz, and is converted to an analog / digital converter (A / A / D).
The data is converted into a digital data signal of, for example, 16 bits per word by a D converter 3. The 16-bit digital data of one word is sent to the bit separation circuit 4 and separated into a data sequence in which the upper 8 bits of each word are extracted and a data sequence of the lower 8 bits of each word.
The data sequence of the upper 8 bits and the data sequence of the lower 8 bits are sent to the multi-level synthesizing circuit 7 via the recording signal forming circuits 5 and 6, respectively.
The value is converted to a multi-valued signal. At this time, the multi-valued synthesis is
When binary reproduction is performed, data of 8 bits per word, which is the original basic format, is read out, and the quaternary signal obtained from the output terminal 8 is transmitted via the transmission system 10.

The transmission of the quaternary signal via the transmission system 10 is, for example, transmission / reception via a transmission line, or recording / reproduction via a recording medium, and the transmitted quaternary signal is a signal. It is supplied to the input terminal 11 on the reproduction (reception) side.

The signal supplied to the input terminal 11 is read as quaternary data by a multi-level signal demodulation circuit (reading circuit) 12, and is separated into two high-order bits and two low-order bits representing the quaternary data. Sent to Bit array circuit
In 13, eight upper bits are sequentially arranged to form 8-bit data. Similarly, eight lower bits are sequentially arranged to form 8-bit data, and these are arranged on the upper side and the lower side to form 16-bit data. The 16-bit data is converted into an analog signal by a digital / analog converter (D / A converter) 14 and taken out via an output terminal 15.

Here, the operation of the recording signal forming circuits 5 and 6 and the multi-value synthesizing circuit 7 will be described with reference to FIG. In FIG. 2, the one word
As a specific example of 16-bit data, a signal waveform in a case where one word of 3A5BH (H indicates a hexadecimal number) is converted into a quaternary signal is shown.

First, the 16-bit data 3A5BH is 0 in binary notation.
011101001011011. If this is simply quaternized in order from the MSB (most significant bit), 0011 10 10 01 01 10 11
It becomes eight (8 digits) data (that is, 03221123 in quaternary notation) and becomes a quaternary signal as shown in FIG. 2A.
Even if the quaternary signal a is read in binary, it is not possible to obtain 8-bit data of one word, which is the original basic format. On the other hand, the upper 8-bit binary data 001111010 and the lower 8-bit binary data 01011011 of the 16-bit data are combined for each bit and converted into a quaternary value, so that when the binary reproduction is performed, 1 which is the basic format of
Word 8-bit data can be read. That is, as shown in FIGS. 2B and 2C,
The ratio of the amplitude of the signal of the upper 8-bit data (00111010) to the amplitude of the signal of the lower 8-bit data (01011011) is 2:
By modulating one of these signals with the other (or adding them in an analog manner), it is possible to obtain a quaternary (0, 1, 2, 3) data signal as shown in FIG. 2d. it can. These four values 0,1,2,3 are each 2 bits 00,0
1, 10 and 11, and the four-value data 00 01 in FIG.
Each upper bit of the two bits representing the individual value of 10 11 11 00 11 01 corresponds to each bit of the upper eight bit data, and each lower bit of the individual two bits corresponds to each bit of the lower eight bit data. Yes, it is. Then, the quaternary data signal of FIG. 2d is converted to a level L between levels 1 and 2.
If the data is converted into binary data by performing level discrimination using _1-2 as a threshold, one word 8 which is the original basic format
Bit data (high-order 8 bit data as shown in FIG. 2b) can be obtained. This means that the data obtained by performing binary identification with a lower resolution than the quaternary identification on the quaternary signal thus multi-valued and synthesized becomes equal to the original basic format. High compatibility can be ensured.

Incidentally, in the multi-level signal demodulation circuit 12 on the reproducing side in FIG. 1, when the quaternary data obtained by quaternary reproducing the signal in FIG. 1
Each upper bit and each lower bit of the 2-bit 4-value data of 1 11 00 11 01 are separated from each other to form a bit arrangement circuit.
Sent to 13. The bit arrangement circuit 13 arranges 8 bits 001111010, which is obtained by arranging the eight bits for each word of each upper bit, on the upper side and 8 bits 01011011 for each word of each lower bit, on the lower side. , The above-mentioned bit-extended 16-bit data 0011101001
011011 is formed. Thus, FIG.
The extended 16-bit data can be reproduced from the quaternary signal.

According to the embodiment of the present invention, digital data of 8 bits per word is transmitted in the form of a binary signal (recording / reproducing).
In the case of transmitting 16-bit digital data of 1 word and 16 bits in the form of a quaternary signal with respect to the basic format as described above, if the transmitted quaternary signal is read in binary form, Since digital data in a basic format of 8 bits per word can be obtained,
Excellent compatibility.

In the above embodiment, an example is shown in which the number of bits of one word is expanded. However, in addition to the above, the signal is multi-valued in order to increase the number of channels, increase the sampling rate, and increase the recording time. In the case of conversion, the above-described multi-value synthesis method may be adopted.

〔The invention's effect〕

According to the data transmission apparatus according to the present invention, the word length (the number of bits of one word) of the existing basic format is conventionally used.
When the bit-extended data is modulated into a multi-level signal and transmitted (including recording / reproducing), the data of the basic format is set to the upper m bits and the lower bit is extended by (N−m) bits. Then, the signal of each bit of the upper m bits and the signal of each bit of the lower (N−m) bits are combined for each bit, and the multi-valued signal is set so that the upper bit corresponds to the higher value of each value of the multi-valued signal. By performing the conversion, the data in the original basic format can be obtained simply by performing low-resolution reproduction such as simply reading the transmitted multi-valued signal in a binary manner, and is excellent in compatibility.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining an embodiment of a data transmission device according to the present invention, and FIG. 2 is a waveform diagram for explaining the operation of the embodiment. DESCRIPTION OF SYMBOLS 1 ... Signal input terminal 4 ... Bit separation circuit 5 ... Higher side recording signal forming circuit 6 ... Lower side recording signal forming circuit 7 ... Multi-level synthesis circuit 10 ... Transmission system 12 ... Multi-level Signal demodulation circuit 13 …… Bit array circuit

Claims (1)

(57) [Claims] 1. An N-bit digital data of one word (N is a positive integer) is converted into upper m bits (m is a positive integer and N> m).
Separating means for separating the lower-order (Nm) bits into upper and lower (N-m) bits; a higher-order recording signal forming means for extracting a signal representing a value for each bit of the upper-order m bits; The lower-order recording signal forming means for extracting a signal representing the value of the upper-order recording signal forming means and the signals output from the upper-order recording signal forming means and the lower-order recording signal forming means, respectively. And a multi-level synthesizing means for multi-leveling by synthesizing bit by bit by making the amplitude of the signal larger than the multi-level signal, and transmitting the multi-level signal synthesized by the multi-level synthesizing means. Data transmission device.