JPS62131648A - Signal transmission system - Google Patents

Abstract

PURPOSE:To attain unipolar signal transmission without widening a transmission signal band by converting the 2nd level signal alternately into the 1st level signal and the 2nd level signal after the 2nd level signal is inserted when prescribed bits of the 1st level signal in a binary digital signal are consecutive. CONSTITUTION:A signal inserting section 1 counts the bit number of a continuous signal when '1's in an input signal 100 are consecutive and when the section 1 detects consecutive 8-bit of '1', the section 1 inserts a 0 signal next to the consecutive 8-bit of '1'. Then a signal inverting section 2 inverts '0' level of a signal 200 inputted into '1' or '0' to form a signal 300. No consecutive 9-bit in the signal 300 sent on a unipolar signal transmission line 3 exists for both 0 and 1 levels and the trouble of widened transmission signal band or disabled unipolar signal transmission is not caused.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a signal transmission system for digital signals suitable for a unipolar transmission system.

[Technical Background of the Invention] Conventionally, binary digital signal transmission methods include (1) transmission as is, (2) mbnb signal conversion method, that is, converting m bits into n bits and transmitting the signal. There are various methods, such as (4) converting into a multi-level signal like a bipolar signal and transmitting it, and (4) transmitting after adding a scrambler operation.

"Problems with the Background Art" However, the above binary digital signal transmission system had the following drawbacks.In the above methods (1) and (4),
11 II or 'O'' may continue for a long period of time, making it difficult to extract the timing signal when receiving these signals.Also, in method (2), it is difficult to extract the timing signal. For example, converting 1 bit to 2
When the signal is converted to bits, the signal band doubles, and when converting from 5 bits to 6 bits, the circuit becomes complicated. Furthermore, in the method (3) above, for example, AM I (Alternative Mark
When using a ternary signal such as HDB3 in the Inversion) system, bipolar signal transmission of positive pulses and negative pulses must be performed, making it impossible to perform unipolar signal transmission like optical fiber signal transmission. There were flaws.

``Object of the Invention In view of the above-mentioned drawbacks, the object of the present invention is to suppress the generation of continuous signals of the same sign without widening the transmission signal band, and
An object of the present invention is to provide a signal transmission method that enables unipolar signal transmission.

[Summary of the Invention] The present invention provides two signals consisting of a first level signal and a second level signal.
When the first level signal of the binary digital signal is continuous for a predetermined number of bits, a second level signal is inserted adjacent to these continuous signals, and then the second level signal of the binary digital signal is
A method of transmitting a binary digital signal obtained by alternately converting a level signal and a second level signal, and converting the first level signal of the binary digital signal to the previous signal state obtained by the conversion. By adopting this, it is possible to suppress the generation of continuous signals of the same sign without widening the transmission signal band, and to achieve the purpose of enabling unipolar signal transmission.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing an embodiment of a digital signal communication system to which the signal transmission method of the present invention is applied. 1 is a signal insertion unit that inserts a 110 I+ signal into a specific position of the input signal 100 to produce a signal 200; 2 is a signal inversion unit that inverts the input signal 200 to produce a signal 300; 3 is a unipolar signal transmission line (for example, an optical fiber transmission line, etc.), 4 converts the signal 300 in the opposite manner to that of the signal inverter 2, and converts the signal 300 into a signal 4.
00, and 5 is a signal deletion unit that deletes a specific Ow+ signal from the signal 400 to produce a signal 500.

Next, the operation of this embodiment will be explained. First, the signal insertion unit 1 counts the number of consecutive signal bits when 1'' in the input signal 100 is consecutive. For example, when it detects that 111 It is 8 consecutive bits, it
11 I+ times signal, then 110 I+ times signal is inserted. For example, in an example like the message @100 shown in Figure 2, 111
After 8 consecutive bits of II, a 1101+ signal is inserted to create signal 200 in FIG.

Note that the in On signal indicated by an arrow in the signal 200 is a signal inserted by the signal insertion section 1. Next, the signal inverter 2 converts the input signal @200 “011” into LL 1
The I+ signal is alternately inverted to the 011 signal, and the signal 20
A signal 300 is generated by converting this signal to the previous signal state of 0. Looking at the operation of this signal inverter 2 using the example shown in FIG.
Assuming that 0 $1 is converted to "O" in signal 300, the next "1" in signal 200 means that the signal before this signal is "0".
011, the signal 300 is converted to "OIt", and the next "O" signal of the signal 200 is "'1" in the signal 300.
Similarly, the signal @200 becomes the signal 300. This signal 300 is transmitted on the unipolar signal transmission line 3 and input to the signal restoration section 4. In this signal restoration section, the signal at Oto “1” in 300
Or set the set of ``1''''O'' to ``0'' in the signal 300.
Processing is performed to convert the set of "1" or tt Oto tt
□ The set It is converted to 091 in the signal 400. However, "X" is the previous signal state, and di 1 It is assumed here. Next to signal 300 “10 ll ll O$
The set of 1 is converted to 1" in the signal 400, and the next "101
The set 11111+ is 110 for signal 400? +, the next set of I It 110 It is converted to at On, and so on, and finally the signal 300 is converted to signal @400. However, two of the signals 300 in FIG. 2 show an example of a combination of signals from the signal restoration section 4. Next, the signal deletion unit 5 deletes the "O" signal after 8 consecutive bits of ``1'' in the signal @400 to obtain a signal 500. If we look at the processing of this signal deletion unit 5 in the example of FIG.
00, a timing signal is extracted, and various processing is performed on the signal 500 using this extracted timing signal.

According to this embodiment, the signal 300 transmitted on the unipolar signal transmission path 3 does not have a continuous signal of 9 bits or more for either the 'O' or 1' signal, and the signal 300 is transmitted on the unipolar signal transmission line 3. Timing signal extraction during reception can be easily performed. In addition, although signal 300 includes more "'OPA signals" than signal 100, since it is essentially a binary digital signal of the same system, the transmission signal band may be expanded or unipolar signal transmission may be performed. There will be no inconvenience such as not being able to do so.

[Effects of the Invention] As described above, according to the signal transmission method of the present invention, when the first level signal of a binary digital signal is continuous for a predetermined number of bits, after inserting the second level signal after these continuous signals, , converting the second level signal of the binary digital signal alternately into a first level signal and a second level signal, and converting the first level signal of the binary digital signal into a pre-signal state where one is exclusively used by the conversion. 2 obtained by converting
By transmitting a base digital signal, generation of continuous signals of the same sign can be suppressed without widening the transmission signal band, and unipolar signal transmission can be performed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a digital signal communication system to which the signal transmission method of the present invention is applied, and FIG. 2 is a diagram showing an example of signal conversion in the system shown in FIG. 1...Signal insertion section 2...Signal inversion section 3...
・Unipolar signal transmission line 4...Signal restoration unit 5...Signal deletion unit Agent Patent attorney Nori Chika Ken Yudo Sanno -

Claims (1)

[Claims] When the first level signal of the binary digital signal consisting of the first level signal and the second level signal is continuous for a predetermined number of bits,
After inserting a second level signal after these continuous signals, the second level signal of the binary digital signal is alternately converted into a first level signal and a second level signal, and the first level signal of the binary digital signal is A signal transmission system characterized in that a binary digital signal obtained by converting a signal to a previous signal state obtained by the conversion is transmitted.