JPH06276159A - Transmitting device - Google Patents

Abstract

PURPOSE:To reduce the change of a frequency characteristic in a transmission loss and to obtain a device usable in water by converting input electromagnetic wave into an optical signal and converting it into electromagnetic wave with the same frequency as that of an input after transmission through an optical fiber. CONSTITUTION:A semi-conductor laser as an electromagnetic wave-optical converter 8 modulates oscillation light by electromagnetic wave by superimposing electromagnetic wave on an impression voltage. The modulated optical signal is transmitted to an optical-electromagnetic converter 9 at a fixing side with an optical fiber cable 13. The converter 9 consists of an avalanche photodiode, etc., which is satisfactory in high speed responsiveness and gets the modulated optical signal back to original electromagnetic wave so as to output it. In result, the optical signal can be transmitted even in water in the part of a cable 13 so that the frequency characteristic of the transmission loss with small change can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission device for transmitting electromagnetic waves of relatively high frequency in water.

[0002]

2. Description of the Related Art FIG. 4 is a partially cutaway perspective view showing an example of a conventional transmission device disclosed in, for example, Japanese Patent Laid-Open No. 56-47101, in which 1 is an input end, 2 is an output end, Three
Is a rectangular waveguide, and 15 is a slit provided in the center of the H surface (magnetic field surface) of the rectangular waveguide 3 along the axial direction. Reference numeral 4 denotes a coaxial line, and its inner conductor 4a is inserted into the waveguide 3 through the slit 15 of the rectangular waveguide 3.
Reference numeral 5 is a non-reflection terminator connected to one end of the waveguide 3.
Reference numeral 6 is an isolator provided between the input end 1 and the coaxial line 4, and electromagnetic waves are transmitted only from the input end 1 to the coaxial line 4. Reference numeral 7 is a stand as a movable body which is mechanically fixed to the outer conductor 4b of the coaxial line 4 and is attached so as to hold the rectangular waveguide 3. This stand 7 is the above coaxial line 4
The inner conductor 4a of the coaxial waveguide 4 is inserted along the slit 15 of the rectangular waveguide 3 into the rectangular waveguide 3 while keeping the length of the inner conductor 4a constant. You can move.

Next, the operation will be described. Here, the input end 1 will be described as the moving side and the output end 2 as the fixed side. The electromagnetic wave applied to the input end 1 is transmitted to the coaxial line 4 via the isolator 6, and passes through the slit 15 of the rectangular waveguide 3 to project into the rectangular waveguide 3 and the inner conductor 4a of the coaxial line 4a.
Conveys some of its energy into the rectangular waveguide 3. The electromagnetic wave transmitted to the rectangular waveguide 3 is transmitted through the coaxial line 4
From the point of coupling with and, it advances in both directions of the rectangular waveguide 3. One proceeds toward the output end 2 and reaches the output end 2, and the other proceeds toward the non-reflection terminator 5, and the energy thereof is absorbed by the non-reflection terminator 5. Isolator 6 is input end 1
The electromagnetic wave from is transmitted only in the direction of the coaxial line 4, and the electromagnetic wave input from the opposite direction is absorbed and is not output.
That is, the electromagnetic wave remaining from the coaxial line 4 not coupled to the rectangular waveguide 3 enters the isolator 6 from the coaxial line 4,
The energy is absorbed by the isolator 6, and the input terminal 1
Is not transmitted to. The non-reflection terminator 5 absorbs the electromagnetic wave transmitted from the coupling point to the non-reflection terminator 5 as described above. Therefore, if there is no anti-reflection terminator 5, the electromagnetic wave traveling in this direction is reflected here and travels in the direction of the output end 2 and interferes with the electromagnetic wave traveling directly from the coupling point to the output end 2. This interference can be eliminated by the non-reflective terminator 5. Therefore, by connecting to each of the input and output ends 1 and 2 a transmission line having a characteristic impedance equal to the characteristic impedance of the input and output ends, a transmission line that is not affected by reflection can be obtained.
By moving the table 7, the movable input end 1 can be moved by a distance substantially equal to the length of the slit 15 provided in the rectangular waveguide 3.

[0004]

Since the conventional transmission device is constructed as described above, water enters the rectangular waveguide 3 through the slit 15 of the rectangular waveguide 3 and the inside of the rectangular waveguide 3 is prevented. Has the drawback that it cannot be used in water because it cannot transmit electromagnetic waves. Therefore, it is conceivable to use a coaxial cable having flexibility and water resistance as a transmission line used in water as shown in FIG. In the figure, 1
A is an input end on the moving side, 2A is an output end on the fixed side, and
A is a coaxial cable having water resistance and flexibility. The input end 1A moves to the left and right in the figure, and the distance between the input and output ends 1 and 2 can be changed by the length of the coaxial cable 14. However, the reliability and water resistance of the coaxial cable deteriorate as the number of mechanical bends increases, and the frequency of the electromagnetic wave to be transmitted is in the X band (8 GHz to 12 GHz).
z) or more, the frequency characteristic of transmission loss deteriorates.
At present, there is no coaxial cable that clears such drawbacks. That is, under the present circumstances, there is no transmission device that can be used underwater, can maintain the reliability and water resistance of the transmission line itself, and has good frequency characteristics of transmission loss even in high frequency electromagnetic wave transmission.

According to the present invention, the frequency characteristic of the transmission loss is good in the transmission of electromagnetic waves of high frequency where the frequency characteristic of the transmission loss is deteriorated in the coaxial cable as described above.
An object of the present invention is to obtain a transmission device that can be used in water and can change the distance between input and output in water.

[0006]

The apparatus of claim 1 is an electromagnetic wave for converting an input electromagnetic wave having a relatively high frequency into an optical signal.
An optical converting means (converter 8), a water resistant and flexible optical fiber transmission line (cable 13) for transmitting an optical signal,
An optical-electromagnetic wave converting means (converter 9) for converting the transmitted optical signal into an electromagnetic wave having the same frequency as the input electromagnetic wave is provided.

The apparatus of claim 2 is an electromagnetic wave-optical conversion means (converter 8) for converting an electromagnetic wave having a relatively high frequency into an optical signal.
a), a water resistant and flexible optical fiber transmission line (cable 13A) for transmitting an optical signal, and light for converting the transmitted optical signal into an electromagnetic wave having the same frequency as the electromagnetic wave.
Electromagnetic wave converting means (converter 9a), reference signal generating means (generator 10) for generating a reference electromagnetic wave having a frequency that can be responded by each of the converting means, and the electromagnetic wave-to-light converting means (based on the reference electromagnetic wave 10d). An input electromagnetic wave frequency converting means 16a for frequency-converting an input electromagnetic wave 1d having a frequency higher than the response frequency of the converter 8a) into an electromagnetic wave having a frequency which can be responded by the electromagnetic wave-optical converting means, and outputting the electromagnetic wave to the electromagnetic wave-optical converting means. Apart from the reference electromagnetic wave sent to the input electromagnetic wave frequency converting means, the electromagnetic wave-optical converting means, the optical fiber transmission line and the light-electromagnetic wave converting means for transmitting the reference electromagnetic wave to the light-electromagnetic wave converting means (converter 9a) side. The reference electromagnetic wave transmitting means 20 having the same structure as the means, and the light-electromagnetic wave conversion based on the reference electromagnetic wave transmitted through the transmitting means. The frequency of the electromagnetic wave output from stage (converter 9a) are those comprising an output-side frequency conversion means 16b for converting the same frequency as the input electromagnetic wave.

A third aspect of the present invention is a transmission apparatus according to the first or second aspect of the present invention, in which each conversion means and electromagnetic wave input / output terminals 1B and 2B are waterproofed.

[0009]

According to the first aspect of the invention, the electromagnetic wave-to-light converting means modulates the light with the electromagnetic wave using the light as a carrier wave and the electromagnetic wave as a modulating wave. As a result, the input electromagnetic wave is converted into an optical signal and transmitted via the optical fiber transmission line. The light-electromagnetic wave converting means returns the modulated optical signal to the original electromagnetic wave.

In the second aspect of the present invention, the input electromagnetic wave frequency converting means corresponds to the input electromagnetic wave having a high frequency which cannot be handled by the electromagnetic wave-light and light-electromagnetic wave converting means, based on the reference electromagnetic wave. It is converted into an electromagnetic wave having a frequency that can be cut off and supplied to the electromagnetic wave-light conversion means. The electromagnetic wave thus frequency-converted is converted into an optical signal by the electromagnetic wave-optical conversion means, transmitted to the optical-electromagnetic wave conversion means, and returned to the electromagnetic wave as in the first aspect. Further, the reference electromagnetic wave is transmitted to the output side by another route by the transmission device having the same configuration as that of claim 1. The output side frequency conversion means restores the frequency of the electromagnetic wave from the light-electromagnetic wave conversion means to the frequency of the input electromagnetic wave based on the transmitted reference electromagnetic wave.

In the third aspect, the entire apparatus is used in water. Especially when you want to change the distance between the input and output in water,
It can be changed within the range of the length of the optical fiber transmission line.

[0012]

EXAMPLE Example 1 (corresponding to claim 1). An embodiment of the transmission device of the present invention will be described below with reference to the drawings. In FIG. 1, 1B is an input end on the moving side and 2B is an output end on the fixed side. 8 is an electromagnetic wave-optical converter that converts electromagnetic waves into light,
Reference numeral 9 denotes a light-electromagnetic wave converter that converts light into an original electromagnetic wave. Reference numeral 13 is an optical fiber cable as a transmission line having both water resistance and flexibility.

Next, the operation will be described. As the electromagnetic wave-optical converter 8, for example, a semiconductor laser is used. The semiconductor laser can modulate light with an electromagnetic wave by superimposing an electromagnetic wave on an applied voltage while performing optical oscillation (light = carrier wave, electromagnetic wave = modulated wave). Utilizing this characteristic, the electromagnetic wave is converted into an optical signal by being applied to the electromagnetic wave-optical converter 8 having a relatively high frequency in the X band band or the vicinity of the input terminal 1B. The converted optical signal is sent to the fixed-side optical-electromagnetic wave converter 9 via the optical fiber cable 13. As the light-electromagnetic wave converter 9, for example, an avalanche photodiode having a good high-speed response is used, and the modulated optical signal is returned to the original electromagnetic wave and output to the output end 2B.

Therefore, in this transmission device, the optical fiber cable 13 can transmit an optical signal even underwater. Further, the bandwidth of the specific bandwidth 0.2 in the X band of electromagnetic waves is as small as about 0.6 × 10 ^{−14 in the} optical region, so that the frequency characteristic of the transmission loss in the optical fiber cable 13 does not change. You get a small one. Also,
Since the transmission line is an optical fiber cable having water resistance and flexibility, the distance between the input and output can be changed, and the reliability against mechanical bending and water resistance are high.

According to the above structure, it is possible to obtain a device that transmits electromagnetic waves having a relatively high frequency and that can perform transmission in water with little change in frequency characteristics of transmission loss.

Example 2. Example 2 is shown in FIG. In the first embodiment, if the frequency of the input electromagnetic wave exceeds the response frequency (which varies depending on the converter) of the electromagnetic wave-optical converter and the optical-electromagnetic wave converter, it cannot be used. Example 2
Solves this problem by once converting the frequency of the input electromagnetic wave into a frequency that can be transmitted by the transmission device of the first embodiment, then converting it into an optical signal for transmission, and returning it to the transmission wave. It is the one that is converted to the same frequency as the input electromagnetic wave and returned to the original electromagnetic wave. In FIG. 2, 1B is an input end on the moving side and 2B is an output end on the fixed side. 8a, 8
Reference numeral b is an electromagnetic wave-optical converter, and 9a and 9b are optical electromagnetic wave converters. 10 is a reference signal generator for generating reference electromagnetic waves,
Reference numeral 11 is a distributor for distributing the reference electromagnetic wave. Reference numeral 12 is a synchronous oscillator that oscillates in synchronization with the reference electromagnetic wave. Reference numeral 16a denotes an input electromagnetic wave frequency converter that converts the frequency of the input electromagnetic wave into a low frequency that the converter 8a can respond to.
Is an output-side frequency converter that converts an input electromagnetic wave into a high frequency. 13A and 13B are optical fiber cables having water resistance and flexibility. In addition, the electromagnetic wave-optical converter 8b, the optical fiber cable 13B and the optical-
The electromagnetic wave converter 9b constitutes the reference electromagnetic wave transmission means 20.

Next, the operation will be described. After the reference electromagnetic wave 10d from the reference signal generator 10 is divided into two by the distributor 11, one of them is sent to the synchronous oscillator 12 to generate a local oscillation signal 12d, and this local oscillation signal is sent to the electromagnetic wave-optical converter 8a. . On the other hand, with the same configuration as that of the first embodiment, the electromagnetic wave-optical converter 8b converts it into an optical signal, the optical signal is transmitted by the optical fiber cable 13B, and the optical-electromagnetic wave converter 9b converts it into an electromagnetic wave. Then, it is sent to the synchronous oscillator 12 to generate a local oscillation signal, and this local oscillation signal 12d is applied to the frequency converter 16b on the output side. The electromagnetic wave 1d having a frequency higher than the response frequencies of the converters 8a and 9a entering the input terminal 1B is mixed with the local oscillation signal 12d from the synchronous oscillator 12 by the input electromagnetic wave frequency converter 16a, and the electromagnetic wave-
The electromagnetic wave-optical converter 8 is frequency-converted to a low frequency lower than the response frequency of the optical converter 8a and the optical-electromagnetic wave converter 9a.
It is converted into an optical signal by a. This optical signal is sent to the optical-electromagnetic wave converter 9a on the receiving end side by the optical fiber cable 13A and converted into the electromagnetic wave 9d, and this electromagnetic wave 9d is sent to the output side frequency converter 16b. The output side frequency converter 16b is
The local oscillation signal 12d from the synchronous oscillator 12 is converted into the electromagnetic wave 9d.
By mixing with and converting to high frequency electromagnetic wave,
The frequency of the original electromagnetic wave that has entered the input terminal 1B is restored and output to the output terminal 2B.

Therefore, in addition to the effect of the device of the first embodiment, this transmission device transmits even if the frequency of the input electromagnetic wave is a high frequency exceeding the response frequency of the electromagnetic wave optical converter 8d and the optical electromagnetic wave converter 9a. A device capable of

Further, the local oscillation signal 12d added to the input electromagnetic wave frequency converter 16a and the output side frequency converter 16b,
Since 12d are signals that oscillate in synchronization with the reference signal (electromagnetic wave), the frequencies are the same, so the input terminal 1B
The frequency of the electromagnetic wave that has entered can be accurately sent to the output end 2B. (Note that if accuracy is not required and transmission is focused, transmission can be performed without using the synchronous oscillator.) In the first or second embodiment, the input end 1B is located at the moving side and the sending end. Although 2B is the fixed side, the input end 1B may be the fixed side and the output end 2B may be the moving side.

Example 3. FIG. 3 shows another embodiment. In this embodiment, in the embodiment shown in FIG. 1, the input end 1B, the electromagnetic wave-optical converter 8, the optical-electromagnetic wave converter 9, and the output end 2B are surrounded by a waterproof wall 17 made of waterproof glass, quartz glass or the like for waterproofing. It has been given. As a result, it is possible to use the entire transmission device underwater in combination with the water resistance of the optical fiber cable 13, and it is possible to perform electromagnetic wave transmission between input and output where the distance changes underwater. The present embodiment can be applied to the second embodiment.

That is, in the present embodiment, the device for transmitting electromagnetic waves of relatively high frequency has little change in the frequency characteristic of transmission loss, can be used in water, and can change the distance between the input and output in water. A transmission device that can be used even in such a case is obtained.

[0022]

According to the transmission device of the present invention, an electromagnetic wave-optical conversion means for converting an input electromagnetic wave having a relatively high frequency into an optical signal, a water resistant and flexible optical fiber transmission line for transmitting the optical signal, Since it is composed of an optical-electromagnetic wave converting means for converting the transmitted optical signal into an electromagnetic wave having the same frequency as the input electromagnetic wave, the high frequency electromagnetic wave transmission in which the frequency characteristic of the transmission loss becomes worse in the coaxial cable transmission. It is possible to obtain a transmission device which can be performed in water and has good frequency characteristics of transmission loss.

According to a second aspect of the present invention, the input electromagnetic wave having a frequency equal to or higher than the response frequency of the converter according to the first aspect is lowered to a frequency at which the converter can respond on the basis of the reference electromagnetic wave and transmitted, and the reference electromagnetic wave is again output at the output side. Since it is configured to return to the original frequency and output based on the above, in addition to the effect of claim 1, it is possible to transmit an electromagnetic wave having a frequency higher than the response frequency of the converter of claim 1.

According to the third aspect of the present invention, each of the converting means of the first or second aspect of the transmission device and the input and output ends of the electromagnetic wave are waterproofed, so that the entire device of the first or second aspect is used underwater. It is possible to obtain a device capable of changing the distance between the input and the output in water.

[Brief description of drawings]

FIG. 1 is a block diagram showing a transmission device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a transmission device according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a transmission device according to a third embodiment of the present invention.

FIG. 4 is a partially cutaway perspective view showing an example of a conventional transmission device.

FIG. 5 is a cross-sectional view showing another conventional transmission device.

[Explanation of symbols]

 1B input end 2B output end 8,8a, 8b electromagnetic wave-optical converter 9,9a, 9b optical-electromagnetic wave converter 10 reference signal generator 11 distributor 12 synchronous oscillator 13 optical fiber cable (transmission line) 16a input electromagnetic wave frequency converter 16b Output side frequency converter 17 Waterproof wall 20 Reference electromagnetic wave transmission means

Claims (3)

[Claims] 1. An electromagnetic wave-optical conversion means for converting an input electromagnetic wave having a relatively high frequency into an optical signal, a water-proof and flexible optical fiber transmission line for transmitting the optical signal, and the transmitted optical signal as described above. A transmission device comprising: a light-electromagnetic wave converting means for converting an electromagnetic wave having the same frequency as an input electromagnetic wave. 2. An electromagnetic wave-optical conversion means for converting an electromagnetic wave having a relatively high frequency into an optical signal, and water resistance for transmitting the optical signal,
A transmission device comprising a flexible optical fiber transmission line and a light-electromagnetic wave conversion means for converting the transmitted optical signal into an electromagnetic wave having the same frequency as the electromagnetic wave, wherein the conversion means can respond. A reference signal generating means for generating a reference electromagnetic wave having a frequency; and an input electromagnetic wave having a frequency higher than the response frequency of the electromagnetic wave-light converting means based on the reference electromagnetic wave is converted into an electromagnetic wave having a frequency at which the electromagnetic wave-light converting means can respond. In addition to the input electromagnetic wave frequency converting means for converting and outputting to the electromagnetic wave-optical converting means and the reference electromagnetic wave to be sent to the input electromagnetic wave frequency converting means, the reference electromagnetic wave is transmitted to the light-electromagnetic wave converting means side. Electromagnetic wave −
A reference electromagnetic wave transmitting means having the same configuration as the light converting means, the optical fiber transmission line, and the light-electromagnetic wave converting means, and the light-electromagnetic wave converting means based on the reference electromagnetic wave transmitted through the transmitting means. A transmission device comprising an output side frequency conversion means for converting the frequency of an electromagnetic wave into the same frequency as the input electromagnetic wave. 3. The conversion means and the electromagnetic wave input and output terminals are waterproofed.
Item 2. The transmission device according to Item 2.