JPH08172562A - Optical signal transmitter - Google Patents

Abstract

PURPOSE: To send an AV signal between a camcorder and an adaptor without the use of any electric contact. CONSTITUTION: When a camcorder 1 is placed on an adaptor 2, since an engagement section 3 provided to a bottom side of the camcorder 1 and an engagement section 4 provided to an upper side of the adaptor 2 are pressed into contact with each other, 1st and 2nd LEDs 5, 6 and 1st and 2nd PDs 7, 8 are positioned accurately so as to be opposite to each other with a distance of, e.g. 2 to 3cm. An infrared ray emitted from the 1st LED 5 is received by the 1st PD 7 through optical paths 9, 10 and an infrared ray emitted from the 2nd LED 6 is received by the 2nd PD 8 through optical paths 11, 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical signal transmission device for wirelessly transmitting a video signal and an audio signal by infrared rays or the like.

[0002]

2. Description of the Related Art Conventionally, an audio / video cable (hereinafter referred to as "AV cable") has been used as a means for transmitting a video signal and an audio signal reproduced by a camera-integrated VTR (hereinafter referred to as "camcorder") to a television receiver. It was common to connect.

However, in the method of connecting the camcorder and the television receiver with the AV cable, it is necessary to attach / detach the AV cable every time the reproduced image and the sound of the camcorder are viewed, which makes the operation troublesome. There was a point.

Then, as a means for solving such a problem, for example, there is an adapter called a handycam station proposed by the applicant of the present application. This is shown in Figure 2.
As shown in 2, an adapter is provided for outputting a video signal and an audio signal (hereinafter collectively referred to as an “AV signal”) input from a camcorder to a television receiver. Always connect it to the television receiver with an AV cable. Between the camcorder and the adapter, place the camcorder on the adapter and connect the AV terminal on the camcorder and the AV terminal on the adapter. By making contact, the AV signal can be transmitted from the camcorder to the adapter.

This handycam station not only transmits AV signals but also operates the operation mode (PB,
Since it is a multifunctional adapter that can perform settings from FF, REW, etc.) to charging of the battery, it is a useful device for improving the troublesomeness of the connection operation between the camcorder and the television receiver.

[0006]

However, in the above-mentioned conventional adapter, since the AV signal connection with the camcorder is made by contacting the metal AV terminal, the metal terminal having good conductivity is provided. Was necessary. In the case of such an electrical contact, a contact pressure of a certain value or more is required to maintain the conduction.
Therefore, in the case of a connector having electrical contacts, a mechanism for applying contact pressure is required. As a result, when attaching or detaching such a connector, it is necessary to push or pull in a specific direction, and for connectors with many contacts, it is necessary to apply a certain amount of force according to this contact pressure. Was taken. That is, there was some difficulty in attaching and detaching the connector.

The present invention has been made in view of the above problems, and provides an optical signal transmission device for transmitting an AV signal between a camcorder and an adapter without using electrical contacts. The purpose is to

Another object of the present invention is to provide an optical signal transmission device capable of transmitting an AV signal at a low cost between, for example, a camcorder and an adapter.

[0009]

In order to solve the above problems, the present invention is an optical transmission device for wirelessly transmitting an optical signal between a transmission device and a reception device, wherein each of the transmission device and the reception device. By providing an engaging portion at a predetermined portion of the device and bringing the engaging portions into contact with each other, the light emitting means provided in the transmitting device and the light receiving means provided in the receiving device face each other with a predetermined space therebetween. It is configured to do.

Further, according to the present invention, the transmitting device is provided with a plurality of light emitting means, the receiving device is provided with a plurality of light receiving means, and a plurality of channels are transmitted between the light emitting means and the light receiving means facing each other. is there.

Here, the transmitting device is, for example, a camcorder, and the receiving device is an adapter having a function of transmitting the received video signal and audio signal to the vision receiver via the AV cable. In this case, the baseband video signal and the baseband audio signal may be transmitted on independent channels, or the combined signal of the chroma signal, the FM luminance signal and the FM audio signal may be transmitted on independent channels.

[0012]

According to the present invention, the light emitting means and the light receiving means are accurately positioned so as to face each other with a predetermined gap by bringing the engaging part of the transmitting device into contact with the engaging part of the receiving device. You can Therefore, for example, if the engaging portion is provided on the bottom surface of the transmitter and the top surface of the receiver, the positioning can be performed only by placing the transmitter on the receiver.

Further, the baseband video signal and the baseband audio signal, or the chroma signal and the composite signal of the FM luminance signal and the FM audio signal are transmitted through independent channels by making a plurality of light emitting means and light receiving means face each other. be able to.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. [1] Configuration of optical coupling portion (1) First embodiment (FIG. 1) (2) Second embodiment (FIG. 2) (3) Third Embodiment (FIG. 3) [2] Configuration of Optical Signal Transmission / Reception System (1) First Embodiment (FIGS. 4 and 5) (2) Second Embodiment (FIG. 6) (3) Third Embodiment ( (FIG. 7) (4) Fourth embodiment (FIGS. 8 to 10) (5) Fifth embodiment (FIG. 11) (6) Sixth embodiment (FIG. 12) (7) Seventh embodiment (FIG. 13) (8) 8th Example (FIGS. 14-16) (9) 9th Example (FIG. 17) (10) 10th Example (FIGS. 18-21) It demonstrates in detail in order.

[1] Configuration of Optical Coupling Portion (First Embodiment) FIG. 1 is a diagram showing a first embodiment of the optical coupling portion of the optical signal transmission device according to the present invention. In this embodiment, the camcorder 1 is placed on the adapter 2 and the camcorder 1
To send an infrared signal to adapter 2. Engagement portions 3 and 4 are formed on the bottom surface of the camcorder 1 and the top surface of the adapter 2. A convex taper is formed in the engaging portion 3, and first and second LEDs (light emitting diodes) 5 and 6 that generate infrared rays are embedded inside. Also,
A mortar-shaped taper is formed in the engaging portion 4, and first and second PDs (photodiodes) 7 and 8 for receiving infrared rays are provided therein.

Therefore, since the engaging portion 3 and the engaging portion 4 are brought into contact with each other only by placing the camcorder 1 on the adapter 2, the first and second LEDs 5, 6 and the first and second PDs 7,
8 are accurately positioned so as to face each other with a distance of, for example, about 2-3 cm. And the first LED
Infrared rays emitted from 5 are received by the first PD 7 through the optical paths 9 and 10, and infrared rays emitted from the second LED 6 are received by the second PD 8 through the optical paths 11 and 12. The optical paths 9 and 11 and the optical paths 10 and 12 are optically separated.

(Second Embodiment) FIG. 2 is a diagram showing a second embodiment of the optical coupling portion of the optical signal transmission device of the present invention. Here, the parts corresponding to those of the first embodiment are designated by the same reference numerals (the same applies to the following drawings). In this embodiment, the first LED 5 and the first PD 7, and the second LED 6 and the second PD 8 face each other at the tapered surfaces of the engaging portions 3 and 4. For this reason, since dust and the like are less likely to accumulate on the light receiving surfaces of the first PD 7 and the second PD 8, it is possible to prevent a decrease in the light receiving level due to the adhesion of dust.

(Third Embodiment) FIG. 3 is a diagram showing a third embodiment of the optical coupling portion of the optical signal transmission device of the present invention. In this embodiment, a guide groove 13 is provided in the engaging portion 3 of the camcorder 1, and a shutter 14 that can be opened and closed is provided above the first and second PDs 7 and 8. Then, when the camcorder 1 is placed on the adapter 2, the guide groove 13 presses the shutter opening / closing pin 15 so that the shutter opening / closing mechanism 16 using a cam, a spring or the like is operated to open the shutter 14. In this embodiment, it is possible to prevent dirt and dust from adhering to the light receiving surface.

[2] Configuration of Optical Signal Transmission / Reception System (First Embodiment) FIG. 4 is a block diagram showing a first embodiment of the optical signal transmission / reception system of the camcorder and the adapter to which the present invention is applied.

In this figure, the baseband video signal input from the recording / reproducing system (not shown) of the camcorder 1 is amplified by the driver 21 and sent to the first LED 5. The audio signal is low-pass filter 2
The high frequency band is cut by 2 and sent to the synthesis circuit 23.
In the synthesizing circuit 23, the continuous wave pilot signal generated by the pilot signal oscillator 24 is synthesized with the audio signal, and the output thereof is amplified by the driver 25 and sent to the second LED 6. FIG. 5 shows an example of frequency allocation between the audio signal and the pilot signal synthesized by the synthesis circuit 23.

The infrared signals radiated from the first and second LEDs 5 and 6 are received by the first and second PDs 7 and 8 through the above-mentioned optical coupling section and converted into electric signals.
As described above, the first LED 5 and the first PD 7, and the second LED 6 and the second PD 8 are accurately positioned so as to face each other with a close distance therebetween.
Even if the video signal and the audio signal are transmitted in the base band without being modulated, a reception signal having a good S / N can be obtained.

The video signal received by the first PD 7 is A
It is adjusted to a constant level in the GC amplifier 31 and sent to the mute circuit 34. The output of the AGC amplifier 31 is sent to the sync signal separation circuit 32, the sync signal separated here is output to the level detection circuit 33, and the gain of the AGC amplifier 31 is controlled so that the sync signal level becomes constant. When the sync signal separation circuit 31 does not detect the sync signal, the mute circuit 34 is operated to mute the video output.

Similarly, the combined signal of the audio signal and the pilot signal received by the second PD 8 is the AGC amplifier 3
In 5 the level is adjusted to a constant level and sent to the low pass filter 36 and the band pass filter 37. The low pass filter 36 separates the audio signal and outputs it to the mute circuit 38. Also, the bandpass filter 37
Separates the pilot signal and outputs it to the detection circuit 39.
The detection circuit 39 detects the pilot signal, controls the gain of the AGC amplifier 35 so that the level becomes constant, and operates the mute circuit 34 when the pilot signal is not detected.

(Second Embodiment) FIG. 6 is a block diagram showing a second embodiment of an optical signal transmission / reception system of a camcorder and an adapter to which the present invention is applied.

The camcorder 1 of this embodiment has the same structure as that of the first embodiment. On the other hand, the adapter 2 includes a video signal mute circuit 34 and an audio signal mute circuit 3.
The means for controlling the operation of No. 8 is different from that of the first embodiment.
That is, in the present embodiment, the low-pass filter 40 detects the DC component in the output signal of the AGC amplifier 31, thereby identifying the presence or absence of light emission due to the bias current of the first LED 5, and if there is not, the video signal system The mute circuit 34 is activated. Similarly, the low-pass filter 41 detects the DC component in the output signal of the AGC amplifier 35, thereby identifying the presence or absence of light emission due to the bias current of the second LED 6, and if there is not, the mute circuit 38 of the audio signal system. Operate.

(Third Embodiment) FIG. 7 is a block diagram showing a third embodiment of the optical signal transmitting / receiving system of the camcorder and the adapter to which the present invention is applied.

In the present embodiment, since the 2-channel audio signal is transmitted, the FM modulation circuit 51 uses L / R.
Audio signals of, for example, 2.3MHz and 2.8M
Hz, or 4.3 MHz and 4.8 MHz carrier waves are frequency-modulated, unnecessary components are removed by a low-pass filter 52, and the second LE is amplified by a driver 25.
Output to D6. And in the adapter 2 on the receiving side,
L, R by 2-channel bandpass filter 53
Each FM audio signal component is extracted and demodulated by the FM demodulation circuit 54 into L and R2 channel audio signals. The processing of the video signal is the same as in the first and second embodiments except that the mute circuit is not provided.

(Fourth Embodiment) FIG. 8 is a block diagram showing a fourth embodiment of an optical signal transmission / reception system of a camcorder and an adapter to which the present invention is applied. The present embodiment is configured so that composite transmission of video signals and Y / C separated transmission can be selectively realized.

When a composite video signal is transmitted, the composite video signal input from the switch SW1 is converted into an FM composite video signal by the FM modulation circuit 55, an unnecessary frequency component is removed by the high pass filter 56, and the synthesis circuit 57 is used. Send to. A 2-channel FM audio signal is input to the synthesizing circuit 57 with the same configuration as in the third embodiment. Further, in this embodiment,
A control signal (LANC signal) is input. Each of these signals has a frequency component as shown in FIG. 9, is frequency-multiplexed in the synthesizing circuit 57, is amplified by the driver 58, and is supplied to the first LED 5. Thus, during composite transmission, only the first LED 5 is used for signal transmission, and the second LED 6 is not used.

On the other hand, when Y / C separated transmission is performed, a luminance signal is input from the switch SW1, processed in the same manner as in composite transmission, and sent to the synthesis circuit 57. The processing of audio signals and control signals is the same as during composite transmission. Further, the chroma signal is amplified by the driver 59 and supplied to the second LED 6 through the switch SW2. The frequency allocation of each signal in this case is shown in FIG. In this figure, channel 1 is the signal transmitted from the first LED 5 to the first PD 7, and channel 2 is the signal transmitted from the second LED 6 to the second PD 8.

In the adapter on the receiving side, the signal received by the first PD 7 is amplified by the amplifier 63 and sent to the bandpass filter 53, the highpass filter 64 and the lowpass filter 66. Bandpass filter 53
Is for extracting the FM audio signals of L and R respectively. Further, the high-pass filter 64 extracts the FM luminance signal or the FM composite video signal. The low pass filter 66 extracts the control signal.

The FM audio signal taken out by the bandpass filter 53 is demodulated as in the third embodiment,
Is output. The FM luminance signal or FM composite video signal extracted by the high pass filter 64 is F
The M demodulation circuit 65 demodulates it into a luminance signal or a composite video signal and outputs it through the switch SW3.

The switch SW3 is switched by automatically discriminating between composite transmission and Y / C separated transmission.
That is, the output of the second PD 8 is amplified by the amplifier 60,
The ACC circuit 61 controls the chroma level, and the detection circuit 62 detects the presence or absence of the level of the color burst signal. If there is a color burst signal, it is switched to the Y / C separation side, and if not, it is switched to the composite video side. During Y / C separated transmission, the chroma signal output from the ACC circuit 61 is output.

(Fifth Embodiment) FIG. 11 is a block diagram showing a fifth embodiment of the optical signal receiving system of the adapter to which the present invention is applied. In the present embodiment, both types of camcorders of the first embodiment (FIG. 4) and the fourth embodiment (FIG. 8) can be used as the transmitting side camcorder, and the adapter can be used depending on the type of the camcorder. , The operation automatically switches. Hereinafter, the camcorder of FIG. 4 will be referred to as a direct transmission type, and the camcorder of FIG. 8 will be referred to as a Y / C separation type.

As described above, in the direct transmission type,
Baseband video signal on channel 1, channel 2
The audio signal to which the pilot signal is added is transmitted. In the Y / C separation compatible type, F is set to channel 1.
M composite video signal or FM luminance signal, + FM audio signal + control signal, and no signal or chroma signal is transmitted to channel 2. So in the adapter,
If the camcorder is a direct transmission type, a Y / C separation compatible type, or a Y / C separation compatible type, it is switched depending on whether composite transmission or Y / C separation transmission is in progress.

Here, whether the camcorder is the direct transmission type or the Y / C separation compatible type is determined by detecting whether or not the channel 1 has the FM composite video signal or the FM luminance signal. That is, from the output of the amplifier 63 to 6 to 20 by the high pass filter 64.
The frequency band of MHz is taken out and sent to the video carrier detection circuit 67. Here, when the FM carrier component is detected, the switches SW1, SW2, SW3, and SW
4 is switched to the YC separation compatible side (shown as YC). If the FM carrier component is not detected, it switches to the direct transmission side (shown as D).

In the case of the Y / C separation type, whether the composite transmission or the Y / C separation transmission is in progress is discriminated by detecting the presence / absence of a color burst signal by the detection circuit 62 as in the fourth embodiment. , Switch SW5.

(Sixth Embodiment) FIG. 12 is a block diagram showing a sixth embodiment of the optical signal receiving system of the adapter to which the present invention is applied. Like the fifth embodiment, this embodiment can use both the direct transmission type and the Y / C separation compatible type as the transmitting side camcorder, and the adapter automatically switches the operation depending on the type of the camcorder. Replace

In this embodiment, this switching control is performed by detecting whether or not there is an FM audio signal in channel 1. That is, the FM audio signal band is extracted from the output of the amplifier 63 by the bandpass filter 53 and sent to the audio carrier detection circuit 68. Here, when the FM audio signal is detected, the switches SW1, SW2, SW3, and SW4 are set to Y.
Switch to the C separation compatible side. If the FM audio signal is not detected, it switches to the direct transmission side. In the case of the Y / C separation type, the means for identifying whether composite transmission or Y / C separation transmission is in progress is the same as in the fourth embodiment.

(Seventh Embodiment) FIG. 13 is a block diagram showing a seventh embodiment of the optical signal receiving system of the adapter to which the present invention is applied. Like the fifth and sixth embodiments, this embodiment can use both the direct transmission type and the Y / C separation compatible type as the transmitting side camcorder, and the adapter automatically operates according to the type of the camcorder. Will be switched.

In the present embodiment, this switching control is performed by detecting whether or not there is a pilot signal added to the direct transmission type audio signal in channel 2. That is, using the output of the detection circuit 39 for controlling the gain of the AGC amplifier 35,
If a pilot signal is detected, switch SW
1, SW2, SW3, and SW4 are switched to the direct transmission side. On the other hand, when the pilot signal is not detected, it is switched to the Y / C separation compatible type. Y /
In the C separation type, the method of identifying whether composite transmission or Y / C separation transmission is in progress is the same as in the fourth embodiment.

(Eighth Embodiment) FIGS. 14 and 15 are block diagrams showing an eighth embodiment of an optical signal transmitting / receiving system of a camcorder and an adapter to which the present invention is applied. This embodiment can use both types of the camcorder of the third embodiment (FIG. 7) and the camcorder of FIG. 14 as the transmitting side camcorder, and the adapter automatically switches the operation according to the type of the camcorder. Replace The camcorder shown in FIG. 14 is the same as the camcorder shown in FIG. 8 except that channel 1 and channel 2 are interchanged. Hereinafter, the camcorder of FIG. 7 will be referred to as a low end type, and the camcorder of FIG. 14 will be referred to as a high end type.

Switch SW in the adapter of FIG.
The relationship between the switching states of 1 to SW3, the type of camcorder (low end, high end), and the video transmission mode (composite, Y / C separation) is as shown in FIG.

(Ninth Embodiment) FIG. 17 is a block diagram showing a ninth embodiment of the optical signal transmitting / receiving system of the camcorder and the adapter to which the present invention is applied. This embodiment uses a single optical path
The optical signal of the channel is transmitted.

The infrared rays emitted from the first LED 5 and the infrared rays emitted from the second LED 6 pass through the first and second polarizing plates 71 and 72 having polarization planes orthogonal to each other, and then the beam splitter. A single optical path is guided by 73. Then, the beam splitter 74 provided in the adapter 2 divides the beam in the direction of the third and fourth polarizing plates 75 and 76. The third polarizing plate 75 is the first polarizing plate 71.
And the fourth polarizing plate 76 has the same polarizing plane as the second polarizing plate 74. Therefore, the first PD7
Receives only the infrared rays emitted from the first LED 5, and the second
The PD 8 can receive only the infrared rays emitted by the second LED 6.

(Tenth Embodiment) FIG. 18 shows a system for transmitting an AV signal by infrared rays from a camcorder to a television receiver. In this system, like the system described so far, infrared is transmitted to the adapter,
Unlike a system that connects from an adapter to a TV with an AV cable, it directly transmits infrared rays from a camcorder to a television receiver. A camcorder that supports both a system that transmits infrared rays to an adapter and a system that directly transmits infrared rays to a television receiver will be described below.

FIG. 19 is an external view of a camcorder corresponding to both systems, and FIG. 20 is a schematic block diagram thereof. This camcorder is provided with the above-mentioned first and second LEDs 5 and 6 on its bottom surface. further,
A pop-up type light emitting section 81 for transmitting infrared rays to the light receiving section of the television receiver is provided on the upper surface thereof. The selection of the first and second LEDs 5, 6 or the pop-up type light emitting section 81 is performed by switching the switch SW in conjunction with the pop-up mechanism 82 and switching the supply destination of the output of the transmission circuit 83.

FIG. 21 shows an example of frequency allocation for direct infrared transmission from a camcorder to a television receiver.

[0049]

As described above in detail, according to the present invention, the light emitting means and the light receiving means can be accurately positioned so as to face each other with a predetermined gap. Therefore, contactless signal transmission can be performed between the transmitter and the receiver. In addition, even if the video signal, audio signal, or chroma signal is transmitted in the baseband without being modulated, a received signal with a good S / N can be obtained, so a low-cost optical signal transmission that does not require a modulation / demodulation circuit or a filter. The device can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of an optical coupling portion of an optical signal transmission device of the present invention.

FIG. 2 is a diagram showing a second embodiment of the optical coupling portion of the optical signal transmission device of the present invention.

FIG. 3 is a diagram showing a third embodiment of the optical coupling portion of the optical signal transmission device of the present invention.

FIG. 4 is a block diagram showing a first embodiment of an optical signal transmission / reception system of a camcorder and an adapter to which the present invention is applied.

FIG. 5 is a diagram showing frequency allocation of audio signals and pilot signals in the first embodiment.

FIG. 6 is a block diagram showing a second embodiment of an optical signal transmission / reception system of a camcorder and an adapter to which the present invention is applied.

FIG. 7 is a block diagram showing a third embodiment of an optical signal transmission / reception system of a camcorder and an adapter to which the present invention is applied.

FIG. 8 is a block diagram showing a fourth embodiment of an optical signal transmission / reception system of a camcorder and an adapter to which the present invention is applied.

FIG. 9 is a diagram showing frequency allocation when composite transmission is performed in the fourth embodiment.

FIG. 10 is a diagram showing frequency allocation when Y / C separation transmission is performed in the fourth embodiment.

FIG. 11 is a block diagram showing a fifth embodiment of the optical signal receiving system of the adapter to which the present invention is applied.

FIG. 12 is a block diagram showing a sixth embodiment of the optical signal receiving system of the adapter to which the present invention is applied.

FIG. 13 is a block diagram showing a seventh embodiment of the optical signal receiving system of the adapter to which the present invention is applied.

FIG. 14 is a block diagram showing an eighth embodiment of the optical signal transmission system of the camcorder to which the present invention is applied.

FIG. 15 is a block diagram showing an eighth embodiment of the optical signal receiving system of the adapter to which the present invention is applied.

FIG. 16 is a diagram showing a switching state of a switch in the eighth embodiment.

FIG. 17 is a block diagram showing a ninth embodiment of the optical signal transmission / reception system of the camcorder and the adapter to which the present invention is applied.

FIG. 18 is a diagram showing a system for transmitting an AV signal by infrared rays from a camcorder to a television receiver.

FIG. 19 is an external view of a camcorder compatible with both systems.

FIG. 20 is a schematic block diagram of a camcorder for both systems.

FIG. 21 is a diagram showing an example of frequency allocation in the case of direct infrared transmission from a camcorder to a television receiver.

FIG. 22 is a diagram showing a conventional adapter.

[Explanation of symbols]

1 ... Camcorder, 2 ... Adapter, 3, 4 ... Engagement part,
5,6 ... LED, 7,8 ... PD

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location H04B 10/22 H04N 5/765 11/00 11/24 H04N 11/00 (72) Inventor Jiang ▲ Saki ▼ Masa 6-735 Kitashinagawa, Shinagawa-ku, Tokyo, Sony Corporation (72) Inventor Masahiro Kambara 6-735, Kitagawa-Shinagawa, Shinagawa-ku, Tokyo, Sony Corporation

Claims (5)

[Claims] 1. An optical transmission device for wirelessly transmitting an optical signal between a transmission device and a reception device, wherein an engagement part is provided at a predetermined portion of each of the transmission device and the reception device, and the engagement part is provided. An optical signal transmission device, characterized in that the light emitting means provided in the transmitting device and the light receiving device provided in the receiving device are arranged to face each other with a predetermined gap by abutting against each other. 2. The transmission device is provided with a plurality of light emitting means, the receiving device is provided with a plurality of light receiving means, and transmission of a plurality of channels is performed between the light emitting means and the light receiving means facing each other. Optical signal transmission equipment. 3. The transmitter is a camera-integrated video tape recorder, and the receiver is an adapter having a function of transmitting the received video signal and audio signal to a television receiver via an audio / video cable. Item 1. The optical signal transmission device according to item 1 or 2. 4. The optical signal transmission device according to claim 3, comprising a channel for transmitting a baseband video signal and a channel for transmitting a baseband audio signal. 5. A channel for transmitting a chroma signal, and F
The optical signal transmission device according to claim 3, further comprising a channel for transmitting a composite signal of the M luminance signal and the FM audio signal.