JPH088532B2 - Optical transmission stereo playback device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical space transmission stereo reproducing apparatus.

2. Description of the Related Art FIG. 5 and FIG. 6 are block diagrams of a main part of a conventional stereo reproduction apparatus by optical space transmission.

FIG. 5 shows the structure of the transmitter provided on the main body.
And 1'switch the program source connected to the inputs L ₁ , L ₂ , L ₃ , L ₄ or the inputs R ₁ , R ₂ , R ₃ , R ₄ etc. of the left and right channels in a linked manner. This is a program source switching device, and the program source selected by this is guided to the stereo modulator 4 via the volume adjusting devices 2 and 2'and the sound quality correcting circuits 3 and 3 '. In the stereo modulator 4, the signals of the left and right channels are modulated into a single signal, and the modulated signal is amplified by the amplifier circuit 5 and then emitted from the light emitting element 6 as an optical signal.

FIG. 6 shows the configuration of the receiving section provided on the audio output section side, and 27 is a light receiving element for receiving the optical signal from the light emitting element 6, and the optical signal received by the light receiving element 27 is an electrical signal. After being converted into a stereo signal, the signal is amplified by the amplifier circuit 28 and further demodulated by the stereo demodulator 29 into left and right stereo signals. One of the left and right stereo signals demodulated by the stereo demodulator 29 is amplified by the power amplifier 30, and then supplied to the speaker 31.

FIG. 7 is a block diagram showing the actual arrangement of the main body A and the voice output parts B ′ and C ′.
And 1'-3 'are built-in, and the audio output sections B', C'of the left and right channels respectively have 27-31 shown in FIG.
The receiver shown by is built in.

Then, a stereo signal is transmitted between the main body A and the voice output section B'and between the main body A and the voice output section C'by the spatial transmission by the light between the light emitting element 6 and the light receiving element 27 shown in FIGS. As compared with cable transmission, the transmission loss is almost negligible.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-described conventional apparatus, when a person or the like passes through the main body A-audio output section B'or the main body A-audio output section C'to interrupt the signal transmission light, the sound is interrupted. There was a drawback that it would end up. In order to prevent such a situation, conventionally, the light emitting unit and the light receiving unit were arranged at a place higher than the height of a person, and so on. There was a problem that was not utilized.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an optical transmission stereo reproducing apparatus for spatially transmitting light between a main body and a first and a second audio output section using light. First and second light emitting means provided in the first and second audio output sections for converting the stereo signal received from the main body into the optical signal again by the audio output section, and the first and second light emitting means. Second and first light receiving means provided in the second and first audio output sections for receiving the spatially transmitted optical signal from the main body, and the optical signal from the main body in the first and second audio output sections. The signal selection means for selectively deriving either of the optical signals from the second and first audio output sections received by the first and second light receiving means is provided.

Therefore, the spatially transmitted optical signal guided from the main body to the first and second audio output sections is once converted into an electrical signal, and then converted into an optical signal by the first and second light emitting means again. The light is guided to the second and first light receiving means provided in the second and first sound output units. Then, in each of the first and second audio output sections, the light reception signal from the main body and the first and second
One of the received light signals from the second and first audio output sections received by the light receiving means is selected by the signal selection means and is derived as an output signal of the first and second audio output sections. Therefore, even if one of the optical transmission paths for spatial transmission is blocked by an obstacle, the signals of the left and right channels can be reproduced without interruption.

Embodiment FIG. 1 to FIG. 3 are block diagrams of an embodiment of the present invention.

FIG. 1 is a block diagram showing the configuration of the transmitting unit A, and since it has the same configuration as the transmitting unit A of the conventional example shown in FIG. 5, the corresponding parts are designated by the same reference numerals and description thereof is omitted.

FIG. 2 is a block diagram showing the configuration of the receiving unit B or C (corresponding to B and C in FIG. 3). In the figure, either 7 or 7'is a light receiving element for receiving an optical signal from the light emitting element 6 shown in FIG. 1 and converting it into an electric signal,
The other of 7 or 7'is a light receiving element for receiving an optical signal from a light emitting element 14 of the other channel described later and converting it into an electric signal, and the output signal of the light receiving element 7 or 7'is an amplifier circuit, respectively. After being amplified by 8 or 8 ', it is led to the signal selection device 9. The signal selection device 9 selectively derives the output signal of the amplifier circuit 8 or 8 ', and when the output of either the amplifier circuit 8 or 8'is lost, the other output is derived, and both amplifier circuits 8 and 8'are output. Alternatively, when both outputs are derived from 8 ', the output from one of the predetermined amplifier circuits is derived. Reference numeral 10 denotes a stereo demodulator that demodulates the stereo modulated signal from the signal selection device 9 and outputs a demodulated signal of either the left channel or the right channel. The signal demodulated by the stereo demodulator 10 is a power amplifier 11 It is amplified by and is guided to the speaker 12 of the left or right channel. On the other hand, 13 is an amplifier circuit that amplifies the output signal of the amplifier circuit 8, and 14 is a light emitting element that converts the output signal of the amplifier circuit 13 into an optical signal and retransmits it.

FIG. 3 is a configuration diagram showing a coupling state of the transmitter A shown in FIG. 1, the left channel receiver B and the right channel receiver C shown in FIG. In the figure,
Arrows 30 and 31 indicate the transmitter A and the receivers B and C of the left and right channels, respectively.
The optical transmission path between them, arrows 32 and 33 are the receiving parts of the left and right channels.
An optical transmission path between B and C, where 34 indicates a listener.

FIG. 4 is a block diagram showing a concrete configuration using the receiving section shown in FIG. 2 for the left and right channel receiving sections shown in the configuration diagram of FIG.

As is clear from FIGS. 3 and 4, if an obstacle such as a person enters the optical transmission path 30 between the transmitting section A and the receiving section B and interrupts the optical transmission path 30, the optical transmission path 30 becomes unusable. However, the signal path to the receiver B is ensured by using the optical transmission paths 31 and 33. Therefore, the stereo modulated signal transmitted from the light emitting element 6 of the transmitting section A is received by the light receiving element 7 in the receiving section C of the right channel via the optical transmission path 31, and the amplifier circuit 8 is received.
To the signal selection device 9 via. Optical transmission path 30 now
Signal is not guided to the optical transmission path 32 because
No output signal is generated in the light receiving element 7'and the amplifier circuit 8'in the receiver C of the right channel. Therefore, the signal selection device 9 outputs the signal received by the light receiving element 7 of the right channel, demodulates it with the stereo demodulator 10, extracts the signal of the right channel, amplifies it with the power amplifier 11, and then outputs the audio signal of the right channel from the speaker 12. Is output. Further, the stereo signal received by the light receiving element 7 of the right channel via the optical transmission path 31 is taken out as an optical output via the amplifier circuits 8 and 13 and the light emitting element 14, and is received via the optical signal path 33 by the receiving section B of the left channel.
Is guided to the light receiving element 7 '. The signal guided to the light receiving element 7'is converted into an electric signal and then guided to the signal selection device 9 via the amplifier circuit 8 '. Since the transmission path 30 is cut off in the signal selecting device 9, there is no signal input from the light receiving element 7 and the amplifying circuit 8, and the signal selecting device 9 outputs the stereo signal from the amplifying circuit 8 '. The stereo signal derived from the signal selection device 9 is demodulated by the stereo demodulator 10 and the left channel signal is guided to the left channel speaker 12 through the power amplifier 11 and the left channel audio signal is output from the speaker.

Even if the optical transmission path 31 is blocked by some obstacle, the left and right channel audio outputs can be derived from the left and right channel speakers 12 as in the case where the optical transmission path 30 is blocked. .

When the optical transmission paths 32 and 33 between the receiving sections B and C are blocked by an obstacle such as a human, the stereo signals from the transmitting section A are guided to the light receiving elements 7 of the left and right channels by the optical transmission paths 30 and 31. Since no signal is guided to the light receiving element 7 ', the signal received by the light receiving element 7 is output to the left and right channel signal selection device 9, and the left and right channel audio signals are output from the left and right channel speakers 12, respectively.

When none of the optical transmission paths 30, 31, 32, 33 is cut off, stereo signals are derived from the light receiving elements 7, 7'of the left and right channels respectively, but each signal selection device 9 uses the predetermined light receiving element 7 or 7 The output from ′ is selected and the left and right channel audio signals are output from the left and right channel speakers 12, respectively.

Therefore, even if any of the optical transmission paths 30, 31 and 32, 33 is blocked by the obstacle, the signal paths of the left and right channels are secured.

As described above, according to the present invention, any one of the optical transmission paths between the left and right channel audio output sections including the main body section including the transmission section and the reception section coupled by the optical transmission path is blocked by an obstacle. Even if this is done, the audio signal is output from the left and right channels without interruption, and it is not necessary to set the positions of the transmitter and the receiver above the height of a person, which is convenient.

[Brief description of drawings]

FIG. 1 is a block diagram of a transmitter provided on the main body side of the present invention,
FIG. 2 is a block diagram of a receiver provided on the same audio output side, FIG. 3 is a view showing a coupling state of the transmitter and left and right channel receivers by an optical transmission path, and FIG. 4 is the same FIG. FIG. 5 is a block diagram of a transmission unit provided on the main body side of the conventional example, FIG. 6 is a block diagram of a reception unit provided on the same voice output side, and FIG. 7 is the same transmission. FIG. 6 is a diagram showing a coupling state of a light receiving unit and left and right channel receiving units by an optical transmission path. A …… Main body, B, C …… Voice output part, 7 ′ …… Light receiving element, 9 ……
Signal selection device, 14 ... Light emitting element, 30, 31, 32, 33 ... Spatial transmission path of light.

Claims (1)

[Claims] 1. An optical transmission stereo reproduction device for spatially transmitting light between the main body and the first and second audio output parts using light,
First and second light emitting means provided in the first and second audio output sections for converting the stereo signal from the main body received by the first and second audio output sections into an optical signal again, and the first and second light emitting means. And second and first light receiving means provided in the second and first audio output sections for receiving the spatially transmitted optical signal from the second light emitting means, and the first and second audio output sections. A signal selecting means for selectively deriving either an optical signal from the main body or an optical signal from the second and first audio output sections received by the first and second light receiving means is provided. Optical transmission stereo playback device.