JP2002152142A - Signal converting circuit and optical active connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transit to optical signal transmitting between devices without replacing/altering an existing device by providing a signal converting circuit and an optical active connector capable of converting an arbitrary analog signal containing a multi-level signal form to an optical signal and transmitting the optical signal. SOLUTION: A frequency modulating circuit 22 is provided for changing a frequency corresponding to an input signal level, and the output of the frequency modulating circuit 22 is inputted to a light emitting element driving circuit 23, and the strength of the optical signal is modulated. Thus, the optical signal whose frequency changes corresponding to the input electric signal level is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a signal conversion circuit and an optical active connector. For more information, see Ether
The present invention relates to a signal conversion circuit and an optical active connector used for replacing a transmission device that transmits a signal by an electric cable with an optical signal transmission based on a standard such as a net.

[0002]

2. Description of the Related Art With the advance of LSI technology, the speed of computers or LAN devices is increasing. Conventionally, electric cables have been widely used for connection between computers and peripheral devices or between LAN devices. However, with the speeding up of these devices, it has become necessary to increase the speed of transmission between devices. Therefore, the problem that the transmission distance is limited in transmission using an electric cable has become apparent.

[0005] As a method of avoiding the limitation of the connection length by an electric cable, for example, in LAN, it is conceivable to shift to transmission by an optical cable. In this case, the existing equipment is replaced with an optical interface,
It is necessary to newly install an adapter such as a media converter for mutually converting optical signals.

[0004] Therefore, there is a problem that not only replacement of existing equipment and introduction cost of the adapter are incurred, but also it is necessary to newly secure a place for installing the adapter. on the other hand,
In order to shift to optical signal transmission without replacing the device, the electrical / optical signal conversion function and the optical / electrical signal conversion function must be compatible with the electrical cable connector. 2. Description of the Related Art An optical active connector that is built in a connector housing and can be shifted to optical signal transmission without replacing or modifying an existing device has been realized.

FIG. 3 shows a conventional optical active connector. The optical active connector includes an electrical connector 1 for inputting and outputting electrical signals, and an electrical connector for converting electrical signals into optical signals.
An optical signal conversion circuit 2, an optical / electrical signal conversion circuit 3 for converting an optical signal into an electric signal, and an optical connector 4 for inputting / outputting the optical signal
Are arranged in the housing 5. The electrical / optical signal conversion circuit 2 includes a comparator 2a, a light emitting element driving circuit 2
b and a light emitting element 2c, and the optical / electrical signal conversion circuit 3 includes a comparator 3a, a threshold detection circuit 3b,
It comprises a preamplifier 3c and a light receiving element 3d.
Therefore, according to the optical active connector, a function of converting a binary digital electric signal into an optical signal and transmitting the optical signal is realized.

[0006]

In optical signal transmission, the light emission level of the light emitting element has a large temperature dependency, and the connection loss between the optical element and the optical fiber and the coupling loss between the optical connectors have a large variation. , The level of the optical signal reaching the receiving side changes greatly. Therefore, if a transmission method in which the intensity of an optical signal is directly changed according to the intensity of an input electrical signal is employed, the size of the conversion circuit becomes large. Therefore, in a conventional optical active connector, as shown in FIG. It merely realizes the function of converting the signal to an optical signal and transmitting the signal, and cannot be applied to the signal format of multilevel amplitude modulation used in the cable transmission standard for transmitting a high-speed electric signal.

[0007]

According to a first aspect of the present invention, there is provided a signal conversion circuit including a frequency modulation circuit for changing a frequency according to an input signal level, and an output of the frequency modulation circuit being a light emitting element. The present invention is characterized in that an optical signal whose frequency changes in accordance with an input electric signal level is output by inputting to a drive circuit and modulating the intensity of the optical signal.

According to a second aspect of the present invention, there is provided a signal conversion circuit comprising a detection circuit for detecting a frequency change of a signal obtained by electrically converting an intensity change of an input optical signal. The electric signal is reproduced and output from the modulated optical signal.

According to a third aspect of the present invention, there is provided an optical active connector comprising: an optical connector for inputting or outputting an optical signal; and an electrical connector for outputting or inputting an electrical signal. It is characterized by including any one of the signal conversion circuits described above.

According to a fourth aspect of the present invention, there is provided an optical active connector comprising: an optical connector for inputting an optical signal; and an electrical connector for outputting an electrical signal. Item 2 is characterized by including both of the signal conversion circuits described in Item 2, and furthermore, by arranging the respective electrical connectors and optical connectors in the same direction, the transmission / reception function is integrated.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a signal conversion circuit according to the present invention, a transmitting side for inputting an electric signal and outputting an optical signal changes the repetition frequency of light emission / quenching of an output optical signal in accordance with the level of the input electric signal. As a result, a frequency-modulated light intensity signal is output. In the signal conversion circuit of the present invention, the optical signal is input, and the receiving side that outputs the electric signal detects the frequency change of the light intensity signal and converts it into an electric signal, thereby converting the analog signal input to the transmitting side. The same electric signal as the electric signal can be output from the receiving side.

Therefore, the optical active connector of the present invention can transmit an arbitrary amplitude-modulated analog signal including a multi-valued signal format as an input electric signal, thereby widely supporting a high-speed signal transmission standard using an electric cable. be able to.

Embodiment 1 FIG. 1 shows an optical active connector according to a first embodiment of the present invention. In this embodiment, an electrical connector 10 for inputting an electrical signal, an electrical / optical signal conversion circuit 20 and an optical connector 30 for outputting an optical signal are provided in a housing 7.
0. The electrical / optical signal conversion circuit 20 includes an input buffer 21, a voltage controlled oscillator 22, a light emitting element driving circuit 23, and a light emitting element 24.
As the housing 70, a connector housing compatible with the electrical cable connection connector can be used.

Therefore, the electric signal input through the electric connector 10 is input to the input buffer 21 in the electric / optical signal conversion circuit 20, is linearly converted to the voltage level in the circuit 20, and is output to the voltage control oscillator 22. Is entered. The voltage controlled oscillator 22 outputs a pulse train having a frequency proportional to the input voltage, and this pulse train is input to the optical element driving circuit 23.

The optical element driving circuit 23 turns ON / OF the current flowing to the light emitting element 24 at the same frequency as the input pulse train.
F. As a result, a light pulse train having the same frequency as the output of the voltage controlled oscillator 22 is output from the light emitting element 24, and the frequency becomes proportional to the input signal level. still,
Although the present embodiment relates to an optical active connector, the same operation and effect can be achieved even in an embodiment in which the electric connector 10 and the optical connector 30 are omitted and only the electric / optical signal conversion circuit 20 is used.

Embodiment 2 FIG. 2 shows an optical active connector according to a second embodiment of the present invention. In this embodiment, an optical connector 40 for inputting an optical signal, an electric / optical signal conversion circuit 5
0 and an electric connector 60 for outputting an electric signal.
0. The electric / optical signal conversion circuit 50 includes an output buffer 51, a detection circuit 52, a limiter amplifier 53, and the light receiving element 24. Case 70
For example, a connector housing compatible with an electrical cable connection connector can be used.

Therefore, the optical signal input through the optical connector 40 is converted into an electric signal by the light receiving element 54 and amplified by the limiter amplifier 53,
Clipped at constant voltage. As a result, the limiter amplifier 53 outputs a pulse train having the same frequency as the repetition frequency of light emission / quenching of the input optical signal.

Further, the output of the limiter amplifier 53 is input to the detection circuit 52 and is converted into a voltage level proportional to a frequency change. The output of the detection circuit 52 is output buffer 51
After being amplified to the same electric signal as the original analog electric signal inputted to the transmitting side, the signal is outputted via the electric connector 60. Although the present embodiment relates to an optical active connector, the same operation and effect can be obtained even in an embodiment in which the electric connector 60 and the optical connector 40 are omitted and only the electric / optical signal conversion circuit 50 is used.

Further, both the electrical / optical signal conversion circuit 20 shown in the first embodiment and the optical / electrical signal conversion circuit 50 shown in the second embodiment are arranged in the housing 70, and the electrical connectors 10, 60 and By arranging the optical connectors 30 and 40 in the same direction, it is possible to integrate the transmitting and receiving functions.

[0020]

As described above in detail with reference to the embodiments, according to the signal conversion circuit and the optical active connector of the present invention, an arbitrary analog signal including a multilevel signal format is converted into an optical signal. It is possible to transfer to an optical signal transmission between devices without replacing / modifying existing devices.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical active connector according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an optical active connector according to a second embodiment of the present invention.

FIG. 3 is a configuration example of a conventional optical active connector.

[Explanation of symbols]

 10, 60 electrical connector 20 electrical / optical signal conversion circuit 21 input buffer 22 voltage controlled oscillator 23 light emitting element driving step 24 light emitting element 30, 40 optical connector 50 optical / electrical signal conversion circuit 51 output buffer 52 detection circuit 53 limiter amplifier 54 Light receiving element 70 Housing

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 31/12 H04B 10/105 10/10 10/22 (72) Inventor Mitsuaki Yanagihashi Otemachi, Chiyoda-ku, Tokyo 2-3-1, Nippon Telegraph and Telephone Corporation F-term (reference) 5F089 AA01 AC10 FA03 FA05 FA06 5K002 AA02 AA04 CA16 DA06

Claims (4)

[Claims] 1. A frequency modulation circuit for changing a frequency according to an input signal level is provided, and an output of the frequency modulation circuit is input to a light emitting element driving circuit to modulate an intensity of an optical signal. A signal conversion circuit for outputting a changing optical signal. 2. An electric signal is reproduced from a frequency-modulated optical signal by providing a detection circuit for detecting a frequency change of a signal obtained by electrically converting an intensity change of an input optical signal. Signal conversion circuit. 3. An optical connector for inputting or outputting an optical signal and an electrical connector for outputting or inputting an electrical signal, and further comprising one of the signal conversion circuits according to claim 1 or 2. Optical active connector. 4. An optical connector for inputting an optical signal, and an electrical connector for outputting an electrical signal, wherein both the signal conversion circuit according to claim 1 and the signal conversion circuit according to claim 2 are provided. An optical active connector having an integrated transmission / reception function by arranging an electrical connector and an optical connector in the same direction.