JPH08163042A - Transmitter - Google Patents

Abstract

PURPOSE: To attain transmission of a signal in an excellent way by reflecting the transmission signal emitted from an infrared ray light emitting means and receiving the reflected transmission signal by an infrared ray receiving means to improve the cut-off characteristic of a transmission line. CONSTITUTION: A digital audio signal S10 outputted from a digital audio equipment 11 is given to a transmitter 12. The transmitter 12 adds a parity for error check to the digital audio signal S10 and re-formats the digital audio signal S10 to be a format suitable for infrared ray transmission. The transmitter 12 modulates digitally the digital audio signal S10 subjected to reformat by using a carrier generated by a prescribed carrier generating circuit and an electric RF signal S11 obtained as the result is outputted to an infrared ray optical emitter 13. The infrared ray emitter 13 generates an optical transmission signal S12. The optical transmission signal S12 is received by an infrared ray detector (light receiving element) 14, in which the signal is converted into an electric RF signal S13 ad the converted signal is outputted to a receiver 15.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Fields of Industrial Application Conventional Technology Problems to be Solved by the Invention (FIGS. 7 to 10) Means for Solving the Problems (FIGS. 1 and 3 to 6) Action Example (1) First Example ( 1 to 3) (2) Second embodiment (FIG. 4) (3) Third embodiment (FIGS. 5 and 6) (4) Other embodiments Effect of the invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission device, and is suitable for application to a voice signal transmission device for transmitting a voice signal by an optical space transmission method using infrared rays.

[0003]

2. Description of the Related Art Conventionally, in this type of audio signal transmission device, a predetermined modulation is applied to an audio signal on the transmitting side, and a light emitting device composed of an infrared light emitter is driven based on the resulting modulated signal. Therefore, an optical transmission signal composed of infrared rays is generated. This optical transmission signal is radiated toward the receiving side, propagates in space, and reaches the receiving side. On the receiving side, this optical transmission signal is received by an infrared receiver, where the optical transmission signal is converted into an electrical signal, and then demodulated to the original audio signal by a predetermined demodulating means. As a result, this type of audio signal transmission device can collectively transmit a desired audio signal to a large number of audio devices without requiring a transmission line, and is used in, for example, a wireless headphone or a speaker device.

[0004]

By the way, in the conventional audio signal transmission device, as shown in FIG. 7, the optical transmission signal S1 is radiated from the light emitting device 1 directly to the light receiving device 2, and is transmitted. The path will be straight due to direct light. For this reason, as shown in FIG.
When an obstacle (for example, a person in the figure) 3 intervenes between and, the transmission path is cut off and the optical transmission signal S1 is interrupted,
This causes a problem that the audio signal cannot be transmitted.

Further, in the conventional audio signal transmission device, as shown in FIG. 9, the optical transmission signal S1 is emitted from the light emitting device 1 with an appropriately wide directivity. Therefore, in such an audio signal transmission device, as shown in FIG. 10, when different channels are transmitted to the light receivers 2A to 2C (that is, when multiple channels are transmitted), the optical transmission signals S1A to S1C are transmitted in space. However, there is a problem in that they cause noise sources to overlap with each other, and as a result, errors increase and good transmission cannot be performed.

The present invention has been made in consideration of the above points, and an object thereof is to propose a transmission device capable of favorably transmitting a transmission signal between a transmission side and a reception side.

[0007]

In order to solve such a problem, in the present invention, a transmission signal S1 composed of infrared rays based on a digital audio signal or a digital video signal S10.
An infrared light emitting means 13 which generates 2 and emits the transmission signal S12 toward a direction other than the receiving side, and a reflecting means 17 which reflects the transmission signal S12 emitted from the infrared light emitting means 13 toward the receiving side. An infrared light receiving means 14 is provided for receiving the transmission signal S12 reflected by the reflecting means 17 and demodulating the digital audio signal or the digital video signal S10 based on the transmission signal S12.

Further, in the present invention, the infrared light emitting means 1
3 is a transmission signal S12 directed toward a plurality of directions other than the receiving side.
To radiate.

Further, in the present invention, a plurality of transmission signals S12 consisting of infrared rays are generated based on a plurality of digital audio signals or digital video signals S10, and the plurality of transmission signals S12 are narrowly directed toward respective receiving sides. Of the infrared light emitting means 13 that emits light having a specific property and the transmission signal S12 emitted from the infrared light emitting means 13 and receives the transmission signal S1.
Based on 2, digital audio signal or digital video signal S
A plurality of infrared ray receiving means 14 for demodulating 10 are provided.

[0010]

The transmission signal S1 emitted from the infrared light emitting means 13
2 is reflected by the reflection means 17, and the reflected transmission signal S
Since the infrared light receiving means 14 receives the light 12, the transmission path becomes non-linear, and the blocking resistance of the transmission path is improved as compared with the conventional case. Further, by radiating the transmission signal S12 in a plurality of directions, the blocking resistance of the transmission path is further improved. Further, since the transmission signal S12 is radiated with a narrow directivity, the transmission signal S12 is not spatially overlapped and does not interfere with each other, and the multi-channel transmission can be favorably performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

(1) First Embodiment In FIG. 1, reference numeral 10 denotes an audio signal transmission apparatus for transmitting a digital audio signal as a whole in the optical space by using infrared rays, and a digital audio signal S10 output from a digital audio device 11 is transmitted. Input is made to the transmitter 12 via a coaxial cable or an optical fiber cable. The transmitter 12 adds a parity for error correction to the digital audio signal S10 and re-formats the digital audio signal S10 into a structure suitable for infrared transmission. Further, the transmitter 12 digitally modulates the re-formatted digital audio signal S10 by using a carrier generated by a predetermined carrier generation circuit (for example, QPSK).
(Quadrature Phase Shift Keying) modulation, and the resulting electric RF (Radio Frequency) signal S11 is output to the infrared optical emitter 13.

The infrared light emitter 13 is a light emitter composed of an amplifier circuit, a light emitting diode (or laser diode), a lens, an optical filter, etc., and is driven by an electric RF signal S11 to emit infrared light. To generate an optical transmission signal S12. This optical transmission signal S12
Is received by an infrared detector (that is, a photodetector) 14 configured by an optical filter, a lens, a photodiode (or a phototransistor), etc.
After being converted into the signal S13, it is output to the receiver 15.

The receiver 15 performs a process reverse to the process performed by the transmitter 12, demodulates the electric RF signal S13 to obtain a digital voice signal, and further performs a reverse format reverse process on the digital voice signal. At the same time, the digital audio signal S14 having the same data structure as the digital audio signal S10 is restored by performing error correction. The digital audio signal S14 is sent to the digital audio device 16 via a coaxial cable or an optical fiber cable. Thus, the digital audio signal S10 output from the digital audio device 11 is the audio signal transmission device 1
It is transmitted to the digital audio device 16 via 0.

Here, in the audio signal transmission device 10,
As shown in FIG. 2, the optical transmission signal S12 is a frequency assigned for high-quality sound transmission in the frequency band of the infrared transmission system assigned by CP-1205 of EIAJ (Japan Electronic Machinery Manufacturers Association). 3 to 6 [MHz] in the band
Use to send.

Further, in the audio signal transmission device 10, as shown in FIG. 3, the optical transmission signal S12 is directed to the ceiling 17 by directing the infrared optical emitter 13 right above or obliquely upward.
It is radiated so as to hit vertically or diagonally to. Then, in the audio signal transmission device 10, the infrared transmission 14 receives the optical transmission signal S12 diffusely reflected by the ceiling 17. In this way, the optical transmission signal S12 is radiated toward the ceiling 17, and the optical transmission signal S12 diffusely reflected by the ceiling 17 is received, whereby the infrared light emitter 13 and the infrared detector 1 are received.
Even if an obstacle (for example, a person in the figure) 3 intervenes on the line connecting 4 and 4, the infrared detector 14
Can receive the optical transmission signal S12.

In the case of this embodiment, in practice, the optical transmission signal S12 is emitted with directivity of an appropriate width, so that the reflection point has not a single point but a predetermined area. As a result, the optical transmission signal S12 is diffusely reflected in an appropriate width and can be received by the infrared detector 14. Further, in this case, since the optical transmission signal S12 is diffused due to irregular reflection, the transmission power of the optical transmission signal S12 is increased as compared with the conventional case and is transmitted.

In the above configuration, the audio signal transmission device 1
At 0, by directing the infrared light emitter 13 right above or obliquely upward, the optical transmission signal S12 is emitted vertically or obliquely to the ceiling 17, and the optical transmission signal S12 reflected by the ceiling 17 is reflected by the infrared detector 14. By receiving the light, the possibility of interrupting the optical transmission signal S12 is lower than in the conventional case, and thus it is possible to prevent the data loss caused by the interruption. That is, in the audio signal transmission device 10, the optical transmission signal S12 is transmitted not directly to the receiving side but by transmitting the optical transmission signal S12 to the receiving side in a non-linear manner via a predetermined reflecting means. It is possible to improve the breaking resistance of the road.

According to the above construction, by transmitting the optical transmission signal S12 non-linearly via the predetermined reflection means 17, it is possible to improve the blocking resistance of the transmission line and thus transmit. The optical transmission signal S12 can be satisfactorily transmitted between the reception side and the reception side.

(2) Second Embodiment In this second embodiment, the infrared light emitter 13 is not used.
The two infrared light emitters 13 emit the optical transmission signal S12. That is, as shown in FIG. 4A, one infrared light emitter 13A emits the optical transmission signal S12A toward the ceiling 17, and the other infrared light emitter 13B emits the optical transmission signal S12B to the infrared detector 14. Radiate directly to. As a result, the infrared detector 14 causes the optical transmission signal S12 reflected by the ceiling 17 to be transmitted.
Both A and the optical transmission signal S12B that is direct light are received, and as shown in FIG.
Even when the light is blocked by the other, the other light can be received. In this way, in the case of the second embodiment, the two infrared light emitters 13A and 13B radiate the optical transmission signals S12A and S12B to form two transmission paths. The blocking resistance of the transmission line is further improved than in the case.

Incidentally, in the case of the second embodiment, the two infrared light emitters 13A and 13B have the same electric RF.
It is driven by the signal S11 and generates the same optical transmission signals S12A and S12B. Therefore, if the infrared detector 14 receives one of the optical transmission signals S12A and S12B, the electric RF signal S13 can be reproduced to demodulate the digital audio signal S14. When there is no obstacle 3, the infrared light detector 14 receives two optical transmission signals S12A and S12B.
Since the frequency bands of 12A and S12B are 3 to 6 [MHz], they do not interfere with each other and affect each other.

According to the above construction, the two infrared light emitters 13A and 13B radiate the optical transmission signals S12A and S12B to form two transmission paths, thereby further blocking the transmission paths. The characteristics can be improved, and thus the optical transmission signal S12 can be satisfactorily transmitted between the transmission side and the reception side.

(3) Third Embodiment In the third embodiment, a plurality of infrared light emitters 13 and a plurality of infrared detectors 14 are provided, and different digital audio signals S10 are provided between the infrared light emitters 13 and the infrared detectors 14, respectively. Optical transmission signal S based on
By transmitting 12, the multi-channel transmission is performed.
In the case of the third embodiment, as shown in FIG. 5, the infrared light emitter 13 is designed to radiate the optical transmission signal S12 with a narrow directivity by using a narrow directivity lens. The multi-channel transmission is realized by avoiding the spatial overlap of the transmission signals S12.

That is, in this audio signal transmission apparatus, as shown in FIG. 6, for example, the infrared optical emitter 13a outputs optical transmission signals S12a to S12c of the same frequency generated based on different digital audio signals S10.
13c to the infrared detectors 14a to 14c to perform multi-channel transmission. In this case, since the optical transmission signals S12a to S12c are radiated with the narrow directivity as described above, the optical transmission signals S12a to S12c do not spatially overlap and interfere with each other, and the optical transmission signals S12a to S12a to Even if S12c has the same frequency, good multi-channel transmission can be performed.

Incidentally, in the conventional case, since the infrared light emitter having a wide directivity is used, if the optical transmission signal is emitted at an angle narrower than the directivity angle (see FIG. 10), the optical transmission signal of the same frequency will be emitted. There was interference as they overlapped each other. That is, in the conventional case, the optical transmission signals are mutually noise sources and the signal noise ratio (S / N) is deteriorated, so that the error rate is deteriorated and good transmission cannot be performed. However, in the case of this embodiment, by using the narrow directivity infrared light emitters 13a to 13c as described above, the overlapping of the optical transmission signals S12a to S12c can be avoided, and a good multi-channel can be achieved even within the same frequency band. Can be transmitted. That is, in this audio signal transmission device, multi-channel transmission is realized by performing spatial division using the narrow directivity infrared light emitters 13a to 13c.

Thus, according to the above configuration, the emission angles of the optical transmission signals S12a to S12c are reduced by using the narrow directivity infrared light emitters 13a to 13c, and the optical transmission signals S12a to S12a to S12a ... By radiating S12c toward the infrared detectors 14a to 14c, respectively, good multi-channel transmission can be performed even within the same frequency band, and thus the optical transmission signals S12a to S12c can be satisfactorily transmitted between the transmitting side and the receiving side. be able to.

(4) Other Embodiments In the above first and second embodiments, the case where the ceiling 17 is used as the reflection means for the optical transmission signal S12 has been described, but the present invention is not limited to this. A wall or a predetermined reflector may be used as the reflection means of the optical transmission signal S12. When the ceiling 17 or the wall is used, the reflection efficiency may be increased by disposing a reflection screen at the reflection point, applying a reflection agent, or making the reflection point white.

In the second embodiment described above, the case where two infrared light emitters 13 are provided to form two transmission paths has been described, but the present invention is not limited to this, and a plurality of infrared light emitters 13 are provided. Alternatively, a plurality of transmission paths may be formed (that is, multipath conversion may be performed). By forming a plurality of transmission paths in this way, it is possible to further improve the blocking resistance of the transmission path and to extend the reach of the optical transmission signal S12, so that the receiving side moves or the receiving side moves. It is suitable when there are a plurality of them.

Further, in the above-mentioned second and third embodiments, the case where a plurality of infrared light emitters 13 are provided has been described, but the present invention is not limited to this, and the infrared light emitters 13 are also provided.
However, only one optical transmission signal generation unit (light emitting diode, lens, etc.) may be provided. In short, if the optical transmission signal S12 can be emitted in multiple directions, the same effect as the above case can be obtained.

Also, in the above embodiment, the transmitter 12
The infrared light emitter 13 and the infrared light emitter 13 are separately provided, and the infrared detector 14 and the receiver 15 are separately provided. However, the present invention is not limited to this, and the transmitter 12 is included in the infrared light emitter 13 and reception is performed. The machine 15 may be included in the infrared detector 14.

Further, in the above-described embodiment, the case where the optical transmission signal S12 is transmitted in the frequency band of 3 to 6 [MHz] is described, but the present invention is not limited to this, and it may be transmitted in other frequency bands. You can

In the above embodiment, the case where the invention is applied to the audio signal transmission device 10 for transmitting the digital audio signal S10 has been described. However, the present invention is not limited to this, and is applied to a video signal transmission device for transmitting a video signal. The present invention can also be applied, and in short, it can be widely applied to a transmission device that transmits a predetermined signal by an infrared transmission method.

[0033]

As described above, according to the present invention, the transmission signal emitted from the infrared light emitting means is reflected by the reflecting means, and the reflected transmission signal is received by the infrared light receiving means. The cut-off resistance is improved, and the transmission signal can be satisfactorily transmitted between the transmission side and the reception side. Also, by radiating multiple transmission signals with narrow directivity, they do not overlap each other spatially and do not interfere with each other, so that the transmission signals can be satisfactorily transmitted between the transmitting side and the receiving side with multiple channels. Can be transmitted.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an audio signal transmission device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a frequency allocation standard for infrared transmission.

FIG. 3 is a schematic diagram for explaining the operation of the first embodiment.

FIG. 4 is a schematic diagram for explaining the operation of the second embodiment.

FIG. 5 is a schematic diagram showing a radiation characteristic of an infrared light emitter in the case of a third embodiment.

FIG. 6 is a schematic diagram for explaining the operation of multi-channel transmission according to the third embodiment.

FIG. 7 is a schematic diagram showing a conventional transmission line.

FIG. 8 is a schematic diagram showing interruption of a conventional transmission line.

FIG. 9 is a schematic diagram showing a radiation characteristic of a conventional light emitting device.

FIG. 10 is a schematic diagram for explaining the operation of conventional multi-channel transmission.

[Explanation of symbols]

1 ... Light emitter, 2 and 2A to 2C ... Light receiver, 3 ... Obstacle, 10 ... Audio signal transmission device, 11, 16 ... Digital audio equipment, 12 ... Transmitter, 13, 13A,
13B, 13a to 13c ... Infrared light emitter, 14,
14a to 14c ... Infrared detector, 15 ... Receiver, 17 ... Ceiling.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04B 10/00

Claims (5)

[Claims] 1. An infrared light emitting means for generating a transmission signal composed of infrared rays based on a digital audio signal or a digital video signal, and emitting the transmission signal toward a direction other than the receiving side, and the infrared light emitting means. A reflection means for reflecting the transmission signal toward the receiving side, and receiving the transmission signal reflected by the reflection means,
An infrared light receiving means for demodulating the digital audio signal or digital video signal based on the transmission signal. 2. The transmission device according to claim 1, wherein the infrared light emitting means emits the transmission signal toward a plurality of directions other than the receiving side. 3. The transmission device according to claim 1, wherein the infrared light emitting means radiates the transmission signal toward a receiving side. 4. Infrared light emitting means for generating a plurality of infrared transmission signals based on a plurality of digital audio signals or digital video signals and radiating the plurality of transmission signals toward respective receiving sides with narrow directivity. And a plurality of infrared light receiving means for receiving the transmission signal radiated from the infrared light emitting means and demodulating the digital audio signal or the digital video signal based on the transmission signal. . 5. The transmission device according to claim 4, wherein the bands of the plurality of transmission signals have the same frequency.