JP2003163654A - Serial signal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make data clear (transparent) without applying a complicated arrangement for serial signals. <P>SOLUTION: Transition interval times corresponding to the 'L' and 'H' of a binary code are set respectively. The polarity of output signals is varied for each bit of the binary code of serial data by the set transition interval time T1 and T2. A receiving side measures a period from the rising to falling or a next rising of the respective digital signals P1 and P2 of the serial signal. The measurements are compared with the set time widths T1 and T2 to discriminate the 'L' and the 'H'. Since data can be defined by the time widths T1 and T2 of the digital signals P1 and P2, the transparency of data can be held without applying complicated arrangements. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial signal suitable for transmission and recording.

[0002]

2. Description of the Related Art In serial data transmission for transmitting binary codes of "H" and "L", the transmitted data cannot be received unless the data delimiter is identified. Therefore, the synchronization information for identifying the bit delimiter is transmitted.

For example, in the asynchronous system shown in FIG. 10A, a start bit and a stop bit are added before and after the character.

However, since the start bit and the stop bit must be added to each character, when transmitting an 8-bit character, a loss of 20% occurs and the transmission efficiency drops.

Further, unless a sufficient idle period is provided between characters, the transparency between the start / stop bit and the data bit cannot be maintained, which is also a problem of lowering transmission efficiency.

On the other hand, in the synchronous system shown in FIG. 10B, a plurality of characters are grouped together and a transmission control character (for example,
(Such as SYN) is added and transmitted. Therefore, the transmission efficiency is better than that of the asynchronous type.

However, even in the method using this transmission control character, if the transmission control character is included in the data, it cannot be transmitted. Therefore, in order to make it transparent, for example, in the BSC procedure, the control character is included in the data. When comes out, the DEL character is attached and sent.

At this time, even if the DEL character is used to make it transparent as described above, the DEL character cannot be included in the data.
DEL when including data equal to the EL character
-The transparency is maintained like DEL.

[0009]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Even if a character is used to make it transparent, there are problems such as the above-mentioned complicated procedure and unnecessary transmission of data for synchronization between the transmitting side and the receiving side. is there.

Therefore, an object of the present invention is to make it possible to clarify data (having transparency) regardless of whether it is synchronous or asynchronous and to transmit data accurately. It is also possible to cope with high-speed communication without wasteful transmission. It is also to be applied to fields other than communication.

[0011]

In order to solve the above problems, according to the present invention, symbols used for serial transmission or serial data format are digital signals with different transition time widths (edge-to-edge time widths). It is possible to employ a configuration in which the digital signals are made to correspond to each other in a ratio of 1: 1 and the levels of the corresponding digital signals are changed for each bit.

By adopting such a configuration, symbols having different time widths and used for serial transmission and serial format, that is, for example, binary data "H" and "L", start bit, stop, In addition to bits, synchronization frames, control frames, etc., character codes etc. can be uniquely expressed. Therefore, the data can be transmitted accurately.

Further, by changing the level of the signal for each bit, it is possible to clarify the division of each signal, so that it is possible to have transparency.

At this time, the above-mentioned symbols are "H" and "L" of data bits of asynchronous serial transmission and start and stop bits provided before and after the data bits, or "H" of data bits in a data frame of synchronous serial transmission. "
And "L" and control characters provided before and after "L" can be adopted.

By adopting such a configuration, serial asynchronous and serial synchronous transmission can be performed with this serial signal.

In this case, it is possible to employ a configuration in which a plurality of data are continuously provided in the data bit or data frame via a digital signal having a transition time width different from that of the data.

By adopting such a configuration, it is possible to transmit a plurality of pieces of data by dividing each piece of data while maintaining transparency with a signal having a time width different from that of data bits. The transmission efficiency can be improved.

Further, at this time, it is possible to adopt a configuration in which the serial data format is the sector format of the disk recording medium.

By adopting such a structure, for example, a hard disk, a C
It can be used for recording on disk media such as D, DVD, FD, MO and MD devices.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the serial signal of this form has a time width between transitions (“H” or “L” output period).
It is composed of two types of digital signals P1 and P2 having different T1 and T2, and these two types of signals having different time widths T1 and T2 between transitions, for example, binary codes "H" and "L". This is the output.

This signal is generated, for example, by the encoding method shown in FIG.

That is, when the digital signal P1 having the transition time width T1 is made to correspond to the binary code "H", from the generation point of the signal level displacement (in this case, the rising edge of the signal in FIG. 2A) ed1. Timing is started (counting base point), and the level is maintained for a predetermined output period (T1 in this case). That is, as shown in FIG. 2B, for example, when the level of the base point is “H”, the level is held for the period of T1.
Similarly, as shown in FIG. 2C, when the level of the base point is "L", the level of "L" is held for the period of T1.

Naturally, the time width T between transitions is set to the binary code "L".
2 corresponds to the digital signal P2 of FIG.
As shown in, the point of occurrence of the displacement of the signal (in this case,
The signal level is held for a period from ed2 to T2, and when the base point level is "L", the level is set to T2.
Hold for. Similarly, when the level of the base point is "H", the level of "H" is held for the period of T2 as shown in FIG.

At this time, the level of the signal changes for each bit. Here, the polarity is reversed. Therefore, as shown in FIG. 1, the output signal is a signal in which “H” level signals and “L” level signals are alternately arranged.

In this way, by inverting the polarity for each bit, for example, even if the same code is continuous in successive bits, the output can be reversed for each code to clearly indicate each bit. .

On the other hand, this signal can be decoded (decoded) into the original binary code by the following reading method.

The basic reading method is, as shown in FIG. 3, a change point of the serial signal S1 (rise of each signal,
Or, fall) start timing from ed3,
The timing is changed to the next signal change point (next rise (“L”
(When changing from level to “H” level) or falling) ed4 is timed (integrated). Then, "H" or "L" is determined depending on whether the time measurement result matches T1 or T2. The set values T1 and T2 are absolute reference values, and an allowable range is provided to supplement them. This allowable range can be smoothly decoded by setting the total sum of the errors that occur when the code is encoded or decoded. And by repeating this,
The code can be read continuously.

If the next change point does not appear even if the allowable range is exceeded during the search for the code, the code has been lost and the end of the data can be detected.

At this time, if the number of codes is determined in advance, the process can be terminated without searching for the code at the time when the reading of the determined number is completed.

As described above, the serial signal starts time counting from the change point ed3 that knows the start of the code, and the time measured at the next change point ed4 is the reference object, and the time counting from this change point ed4 is the reference point. By repeating the above, the original code can be easily decoded.

Incidentally, there is also a method of decoding by replacing the difference between the set value and the integrated value with the start point of time counting.

That is, in this method, time counting is started from the change point ed3 that knows the start of the code, and the time accumulated at the next change point ed4 is referred to. Based on, repeat the timing again.

At this time, the method of taking the difference is (integrated value)-
Calculate with (set value). At this time, when the integrated value is larger than the set value (more time has passed), a + value is entered to correct the actual elapsed time, and a vice versa is entered.
For example, if the set value is 10 and the integrated value is 11, the next counting start starts from 1, and if the integrated value is 9, the next counting start starts from -1. Further, when reading is started at the change point ed3 and the result of the integrated value at the next change point ed4 does not appear even if the result exceeds the allowable range, for example, there is no signal and there is no signal You can confirm that it became.

As described above, in both methods, the sign is defined by the difference between the signal transition time widths T1 and T2 (measurement time), so that only the relative difference can be detected, and the signal expansion is also performed. Wide tolerance. As a result, since it is strong against fluctuations in the level of the waveform and disturbance in the waveform, accurate transmission can be performed.
Therefore, it is also suitable for high-speed communication.

Further, at that time, since the time is measured for each of the base points ed3 and ed4, errors do not accumulate, and at this time, it is not necessary to synchronize the reference clocks for time measurement on the encode side and the decode side. Relative accuracy is sufficient, without requiring precise accuracy.

Further, since the encode circuit and the decode circuit only measure the output period in this way, they can be easily configured by the timer means and the delay means. Therefore, software processing is also possible.

By the way, in this method, since the code is defined by the time widths T1 and T2 between transitions of signals, not only binary codes but also start and stop bits of serial transmission signals and charactor signals for transmission control are used. Define or
It is also possible to define an n-ary code, a character code, or a serial data format (described later).

Therefore, as the second embodiment, first, an example in which the communication start and end are defined as shown in FIG. 4 in place of the start and stop bits will be described, and further applied to a character signal for transmission control. The case is also described.

In FIG. 4, transition time widths T3 and T4 different from the transition time widths T1 and T2 of the digital signals P1 and P2 are shown.
The digital signals P3 and P4 of 1 define the start and end of communication.

In this way, it is possible to easily distinguish the start and end of communication and the data only by measuring the time widths T1, T2 and T3, T4 between the transitions of the signal from the displacement point of the signal.

Therefore, even if a new receiver is added to the receiving side during data transmission (for example, one-to-many communication), the added receiver can easily confirm the data by starting the communication. You can find the beginning of. Also,
Complete data (from the beginning of the data) can be obtained by eliminating the missing data from the middle.

Further, since it is easy to discriminate the signal for starting and ending the communication from the data, it is not necessary to measure the transmission data into blocks and fix the number of data. Therefore, it is also possible to transmit variable-length data.

On the other hand, in the case of synchronous communication using transmission control characters, as described in the conventional example, communication is performed by combining a plurality of characters consisting of several bits. Therefore, instead of the transmission control character, for example, as shown in FIG. 5, the start of the data (text) (the beginning code OD) and the end of the data (the end code ED) can be defined by signals having different time widths. .

In FIG. 5, the beginning of data is indicated by the prefix OD.
Is announced. Even if the data is received from the middle, the data can be correctly received by searching the prefix OD and starting the reception (it can be easily discriminated by measuring the time width between transitions of signals). ).

Further, on the receiving side, since the end of the data can be known by the declaration of the sentence end code OE, the data can be received even if the length of the data is not known in advance.

Further, in FIG. 5, a signal having a transition time width different from that of the data (in this form, an initial letter OD) is provided between the data (text 1) and the data (text 2) so that the two data are continuous. So that it can be transmitted. In this case, the data starts from the initial code OD, and when the initial code OD is detected again, it can be understood that the previous data and the subsequent data are different.

At this time, since the data "H" and "L" and the beginning code OD and the ending code OE are defined by signals having different time widths, the data can have complete transparency. Therefore, the data can be transmitted accurately.

In this embodiment, the prefix OD is used as a signal having a different time width, but the present invention is not limited to this, and a signal having a time width dedicated to the data may be defined in order to divide data. Good.

Next, as a third embodiment, a case where this serial signal is applied not only to a binary code but also to a multi-level code will be described.

FIG. 6 shows an example of creating an octal code. In the creation example, the codes from 0 to 7 are defined by the time width between transitions of the signal.

Therefore, each octal code, which had to be defined by 3 bits, can be defined by one signal having a different time width between transitions.

That is, since the conventional code has a fixed data length, the time required for data transmission was always the same. On the other hand, in this method, the time required for data transmission depends on the time width between the transitions of the signals (a1) to (a) in FIG.
It becomes variable as shown in 3). Therefore, the transmission speed can be improved (a4 and e are also shown in hexadecimal).

Therefore, this method is described below.
When used as a recording medium, it is possible to record at high density.

Note that FIG. 6 shows one example of creating a code, and the present invention is not limited to the set values (for example, set reference values for determining speed) of this created example.

Next, as a fourth embodiment, it will be shown that this signal can be applied to multi-valued levels.

The multi-valued level is not limited to two levels of "H" and "L", but has a plurality of levels such as +3, 0, -3V.

Even when used for such a multilevel level,
As shown in FIG. 8, the level is changed for each signal.

That is, when the code is generated, the level is changed to a target level, and for example, after a predetermined time as shown in FIG. 8B, it is changed to the next level.

Here, the reason why three levels are used is that it is not possible to create a change in binary level for continuous values.

For example, in FIG. 8A, the level A is "L",
If level B is "H", the signal is "no signal" →
When “H” → “H” continues, no level change can occur. Therefore, the level C is provided to assist continuous values as shown in FIG.

That is, the level is changed to "A" at "L", and subsequently "L" is generated, so the level is changed to "C".
Next, since "L" has appeared, the level is changed to level A. In this way, a binary number can be expressed.

In this embodiment, binary values are represented by using "H" and "L" as signals having the same transition time width, but the present invention is not limited to this, and "H" and "L" can be used. If signals with different transition time widths are used, the decimal values are 3, 4, ...
It can be easily increased like a decimal value.

As a fifth embodiment, a case where this signal is used in a serial data format will be described. Examples of such formats include FD, CD, DV
There are formats for recording media such as D, hard disk, and MO device.

A sector format is used in such a disk-shaped recording medium. For example, as a typical example, there is a hard disk write data format shown in FIG. Since such a sector format is generally composed of user data and other control (synchronization, etc.) data, it can be structured similarly to the serial transmission data described above.

Therefore, as described above, when applied to a recording medium, high density recording can be performed.

[0067]

According to the present invention, having the above-mentioned configuration, data can be transmitted clearly and accurately without making a complicated arrangement. Furthermore, high-speed communication can be supported without wasteful transmission. Further, it can be applied to high density recording on a recording medium.

[Brief description of drawings]

FIG. 1 is a serial signal waveform according to a first embodiment.

2 (a), (b), (c), (d), (e) first
Operation explanatory diagram of the embodiment

FIG. 3 is an operation explanatory view of the first embodiment.

FIG. 4 is an operation explanatory view of the second embodiment.

FIG. 5 is an operation explanatory view of the second embodiment.

FIG. 6 is a definition table of the third embodiment.

FIG. 7 is an operation explanatory view of a1, a2, a3, a4, and e third embodiment.

FIG. 8A is a signal waveform according to the fourth embodiment. (B) Definition table of the fourth embodiment

FIG. 9 is an operation explanatory view of the fifth embodiment.

FIG. 10A is a serial signal of a conventional example. (B) Conventional serial signal

[Explanation of symbols]

P1 digital signal P2 digital signal P3 digital signal P4 digital signal T1 transition time width T2 transition time width T3 time interval between transitions T4 transition time width OD bullet OE sentence end code ed1 change point ed2 change point ed3 change point ed4 change point

Claims (4)

[Claims] 1. A symbol used for serial transmission or a serial data format is made to correspond 1: 1 with a digital signal having a different transition time width, and the corresponding digital signal is formed by changing the level for each bit. Serial signal. 2. The symbols are "H" and "L" of data bits of asynchronous serial transmission and start and stop bits provided before and after them, or "H" and "L" of data frames of synchronous serial transmission. The serial signal according to claim 1, which is a control character provided before and after the control signal. 3. The serial signal according to claim 2, wherein a plurality of data are consecutively provided in the data bit or data frame via a digital signal having a transition time width different from that of the data. 4. The serial signal according to claim 1, wherein the serial data format is a sector format of a disk recording medium.