JPH0832627A - Bipolar optical conversion type transmission equipment - Google Patents

Abstract

PURPOSE:To provide an inexpensive bipolar optical conversion type transmission equipment whose transmission speed can be reduced and whose reliability is high. CONSTITUTION:On a transmission-side, the transmission speed of an optical module in an electric to optic conversion circuit 10 is set to be half by dividing a frequency by a frequency-dividing means consisting of a flip flop 1. On a reception-side transmission speed is set to be 7 half by differentiating the output of an optic to electric conversion circuit 12 by a timer 14 and demodulating the result by an exclusive gate 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission device,
In particular, it relates to a bipolar optical conversion type data transmission device.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a bipolar transmission device which has been conventionally used. In FIG. 5, 1 is a flip-flop, 2a and 2b are NAND gates, and 3 is a pulse transformer. RZ bipolar conversion circuit 4 is constructed. Reference numeral 5 is a transmission line, 6 is a pulse transformer, 7a and 7b are comparators, and 8 is an OR gate, and a bipolar RZ conversion circuit 9 on the receiving side is formed.

In bipolar transmission, as shown in FIG.
This is a modulation method in which the flow component of the signal is suppressed by alternately inverting the Z data.

Since the bipolar system has no direct current component, it has a good affinity with the pulse transformer, and since insulation can be easily obtained with the pulse transformer, it is often used for transmission of metal cables such as coaxial cables and twisted pairs.

FIG. 7 shows an example in which the bipolar system is replaced with an optical transmission line. In FIG. 7, 10 is an electrical / optical conversion (E / O conversion) unit of the transmission example, and 12 is a receiving-side optical / electrical conversion (O / E conversion) connected to the E / O conversion unit 12 via the optical transmission cable 11. Conversion) section.

Bipolar transmission is originally an RZ transmission method, and optical transmission is possible as shown in FIG. 8 simply by replacing it with an optical conversion (E / O, O / E) module.

[0007]

As the transmission speed becomes higher, a higher speed such as an optical transmission module and an optical fiber is required, resulting in an increase in cost and technical difficulty.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide a highly reliable bipolar optical conversion type transmission device which enables a reduction in transmission speed and is inexpensive. .

[0009]

In order to achieve the above object, the bipolar optical conversion type data transmission apparatus of the present invention divides the RZ transmission data by a frequency dividing means and the frequency dividing means. RZ-NRZI conversion unit including an electric / optical conversion circuit for converting the generated signal into an optical signal, and the RZ-NRZ
An optical / electrical conversion circuit for converting an optical transmission signal transmitted from the electric / optical conversion circuit of the I conversion unit into an electric signal, and a demodulation of the electric signal converted by the optical / electrical conversion unit to obtain RZ reception data And an NRZI-RZ conversion unit.

Further, the data transmission apparatus of the present invention includes a bipolar RZ conversion section for converting bipolar transmission data into RZ transmission data, a frequency dividing means for dividing the RZ transmission data by the bipolar RZ conversion section, and this frequency dividing means. A transmission adapter including an RZ-NRZI conversion unit having an electro-optical conversion circuit for converting a signal divided by the optical signal into an optical signal, and an optical transmission signal transmitted from the RZ-NRZI conversion unit of the transmission adapter is converted into an electric signal. Optical / electrical conversion circuit and the optical /
RZ demodulates the electric signal converted by the electric conversion circuit
An NRZI-RZ conversion section including demodulation means for obtaining received data, and a reception adapter having an RZ bipolar conversion circuit for converting the RZ reception data obtained by the NRZI-RZ conversion section into bipolar reception data. Characterize.

[0011]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 shows a bipolar optical conversion type transmission device according to an embodiment of the present invention, in which a flip-flop 1 and an electric / optical conversion (E / O conversion) unit 10 are used to transmit an RZ-type signal on the transmission side.
The NRZI conversion unit 13 is formed, and the optical / electrical conversion (O / E conversion) unit 12, the timer 14 and the exclusive OR gate 15 form an NRZI-RZ conversion unit 16.

In the bipolar conversion device of FIG. 1, the transmission data is toggled by the flip-flop 1 to generate E /
After being converted into an optical signal by the O conversion unit 10, it is transmitted to the O / E conversion unit 12 through the optical transmission line 11. O / E
The conversion unit 12 converts the optical signal into an electric signal, and the timer 14
And led to Exclusive or Gate. The electric signal converted by the O / E conversion unit 10 is, as shown in the time chart of FIG.
Pulse width of the RZ signal), and the exclusive OR gate 15 demodulates the RZ signal with the original signal and the delayed signal.

In the time chart of FIG. 2, when the RZ pulse width is T, as compared with the conventional system (FIG. 8),
The pulse width in the optical transmission module is 2T. this is,
FIG. 8 shows that the pulse width of transmission is doubled as compared with the conventional method, and the transmission speed can be half. Although a wide pulse such as 6T is generated, there is no problem because optical transmission can be performed from direct current, unlike a bipolar method using a pulse transformer.

By using the system shown in FIG. 1, it is possible to halve the transmission speed of the optical module in the case of optical transmission in the RZ transmission, and especially when high speed is required, the optical transmission by this system can be performed. The effect of halving the transmission speed is great.
Also, the RZ data is converted into NRZI, and the RZ is received on the receiving side.
In this case, when the bipolar system is used for optical transmission, the transmission speed of the optical transmission unit can be reduced to half and the optical conversion can be easily performed.

In particular, in a high-speed bipolar transmission device, it can be easily realized, for example, when a part of the bipolar transmission is converted into an optical signal. FIG. 3 shows an example.

That is, FIG. 3 shows a bipolar optical transmission device according to another embodiment of the present invention. On the transmission side, a bipolar transmission section 17 and bipolar RZ conversion sections 4 and RZ are provided.
Using the NRZI conversion unit 13, the bipolar RZ conversion unit 4
And the transmission adapter 19 by the RZ-NRZI converter 13
In addition, the reception side uses the NRZI-RZ conversion unit 16, the RZ bipolar conversion unit 9, and the bipolar reception unit 18, and the NRZI-RZ conversion unit 16 and the RZ bipolar conversion unit 9 form the reception adapter 20.

According to the transmission device of FIG. 3, the bipolar RZ conversion circuit 4 of FIG. 5 and the RZNRI conversion circuit 1 of FIG.
By combining 3 into a transmission / reception adapter, bipolar optical transmission can be realized without changing the known bipolar transmission / reception devices 17 and 18.

FIG. 4 shows an example of transmission interfaces 30a and 30b capable of transmitting direct current by a photocoupler. In the figure, 21 is a not gate, 22a and 22b are photocouplers, and 23 is a Schmitt circuit.

The interfaces 30a and 30b can be applied if they can be transmitted from DC, so that the E / O in FIG.
The conversion unit 10 and the O / E conversion unit 12 can be replaced.

Further, if 0 does not continue for more than a certain bit in the transmission data, this is the same in the bipolar system, but 0 may not last long because of clock extraction. This is because in RZ, only 1 can be used for clock extraction. In such a case, the maximum continuous length of 0 is the lower limit of the transmission rate in this method. In such a case, it is not always necessary to transmit from direct current through the transmission line.

[0022]

The present invention is as described above, and according to the invention of claim 1, the transmission speed of the optical module can be reduced by dividing the RZ signal at the time of transmission, and the optical speed at the receiving side can be reduced. By differentiating and demodulating the output of the electrical conversion unit, the transmission speed in the optical transmission unit can be reduced, so that a low cost and highly reliable bipolar optical conversion type data transmission device can be obtained.

According to the invention of claim 2, claim 1
In addition to the effect of the invention described above, it is possible to realize bipolar optical transmission without changing the conventional bipolar transmitter and receiver, which is extremely effective.

[Brief description of drawings]

FIG. 1 is a block diagram of a bipolar optical conversion data transmission device according to an embodiment of the present invention.

FIG. 2 is an operation time chart of the bipolar optical conversion type data transmission device of FIG.

FIG. 3 is a block diagram of a bipolar optical conversion type data transmission device according to another embodiment of the present invention.

FIG. 4 is a circuit diagram of an interface unit used in the present invention.

FIG. 5 is a circuit diagram of a conventional bipolar data transmission device.

6 is a signal waveform diagram of the data transmission device of FIG.

FIG. 7 is a block diagram of a conventional optical transmission device.

8 is an operation time chart of the optical transmission device of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Flip-flop 10 ... Optical / electrical conversion circuit 11 ... Optical transmission line 12 ... Optical / electrical conversion circuit 13 ... RZ-NRZI conversion part 14 ... Timer 15 ... Exclusive OR gate 16 ... NRZI-RZ conversion part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H04B 10/04 10/06 H04L 25/49 C 9199-5K

Claims (3)

[Claims] 1. An RZ-NRZI converter comprising a frequency dividing means for dividing RZ transmission data and an electric / optical conversion circuit for converting a signal divided by the frequency dividing means into an optical signal, and the RZ-NRZI converting section.
An optical / electrical conversion circuit for converting an optical transmission signal transmitted from the electric / optical conversion circuit of the Z-NRZI conversion unit into an electric signal and an electric signal converted by the optical / electrical conversion unit to demodulate R
An NRZI-RZ conversion unit comprising demodulation means for obtaining Z reception data, and a bipolar optical conversion type transmission device. 2. A bipolar RZ conversion section for converting bipolar transmission data into RZ transmission data, and the bipolar RZ.
A transmission adapter including an RZ-NRZI conversion unit having a frequency dividing unit for dividing the RZ transmission data by the conversion unit and an electro-optical conversion circuit for converting the signal divided by the frequency dividing unit into an optical signal, and the transmission adapter. The optical / electrical conversion circuit for converting the optical transmission signal transmitted from the RZ-NRZI conversion unit into an electric signal and demodulation means for demodulating the electric signal converted by the optical / electrical conversion circuit to obtain RZ reception data. NRZI-R
Z conversion unit and RZ for converting RZ reception data obtained by the NRZI-RZ conversion unit into bipolar reception data
A bipolar optical conversion type transmission device comprising: a reception adapter having a bipolar conversion circuit. 3. The transmission device according to claim 1, wherein the electric / optical conversion circuit inputs a knot gate for inputting an electric signal, and a first photocoupler for outputting an electric transmission signal based on an output signal of the knot gate. The photoelectric conversion circuit includes a second photocoupler for converting an electric transmission signal from the first photocoupler into an electric signal and a Schmitt circuit for receiving the electric output signal of the second photocoupler to obtain reception data, A bipolar optical conversion transmission device characterized by the above.