JP2868586B2 - Serial transmission method of audio signal and transmission device thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for serially transmitting a digitized audio signal from a source to a receiving side for reproduction.
The present invention relates to a serial transmission method of such an audio signal and a transmission device thereof.

For example, consider a system component. In the center of a compact disc CD, the main unit consisting of a CD playback device, tuner, amplifier, etc. is placed, and speakers are placed on both sides. Then, audio signals are transmitted from the main body to the speakers on both sides by wire, and sound is output from the speakers.

Here, it is sometimes convenient if audio signals can be spatially transmitted from the main body to the speakers on both sides by replacing the wires with wireless. In this sense, the present invention relates to a serial transmission method of a digitized audio signal in which a main body side is a source and a speaker side is a receiving side, and to a transmitting apparatus therefor.

[Conventional technology]

A method of spatially transmitting a digital signal as a serial optical signal is known from Japanese Patent Application Laid-Open No. 63-152250.

[Problems to be solved by the invention]

On the center body side, the digital audio signal reproduced from the CD reproducing device is output as a serial optical signal from the transmitting device to the space, and on the speaker side, the receiving device and the digital /
Consider a case in which an analog converter (DA converter) and a spooker are prepared and received, and are converted from digital to analog and output as voice.

What matters here is the adjustment of the audio output level output from the speaker. There is no problem if the level of the analog signal after the DA conversion is manually adjusted by the volume on the speaker side, but since the manual adjustment is not convenient, remote control is desired.

In this case, assuming that the remote control signal is output toward the main unit, the digitized audio signal to be transmitted from the main unit is converted so that the audio output level becomes a desired small level before transmission. Then, the signal is transmitted after being attenuated by digital operation by remote control.

In this way, the audio output level can be adjusted by remote control, but since the audio output level is reduced on the transmission side, (quantization error) / (audio output level) increases, and as a result, noise is reduced. And the sound quality (audio performance) is degraded.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems in the prior art and to make it possible to adjust a sound output level by remote control without deteriorating sound quality (audio performance). A transmission method and a transmission device thereof are provided.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, a digital audio signal is transmitted serially from its source to a receiving side, and when it is reproduced there, reproduction performance for realizing reproduction in accordance with the reproduction performance desired by the user. Control signal data is created using the specification code as a reproduction performance control code, and the generation source multiplexes the control signal data with the audio signal data to transmit.

[Action]

Control signal data as a reproduction performance control code is multiplexed with a digital audio signal and transmitted serially.
On the receiving side, the reproduction performance control code signal data is separated from the received signal. The separated reproduction performance control code signal data controls, for example, the volume of an audio amplifier circuit for driving a speaker to a level desired by the user. Therefore, when the audio output level is reduced, the quantization error is reduced at the same ratio as when the audio output level is reduced. Therefore, (quantization error / audio output level) does not increase, and the audio output level can be controlled without lowering the audio performance, thereby achieving reproduction in accordance with the reproduction performance desired by the user.

〔Example〕

 Hereinafter, one embodiment of the present invention will be described with reference to FIG.

FIG. 1 (a) shows a frame format (one frame is composed of 588 bits) after EFM modulation according to the current CD format. In a CD player, data is recorded on a disc according to this format. .

The sync pattern (24 bits) is a pattern for synchronizing frames, and the subcode (14 bits)
Time code and data for CD graphics are recorded here. Data and parity (14 bits)
Is a digital audio data and a parity code for correcting the error. The margin bits (3 bits) are added to satisfy the modulation rule of the EFM signal (the signal length is 3T to 11T, where T is a bit transfer cycle).

FIG. 1 (b) shows the format (8 bits) of the sub-code (14 bits) shown in FIG. 1 (a) before modulation. The EFM modulation method separates data bits into 8-bit data and converts them into 14-bit channel bits.
It is well known that it is used in a disk.

The P-code constituting the sub-code format before modulation is a repetitive signal for access, and the Q-code is a code such as a time code and a song number for display and access. The R, S, T, U, V, and W codes are used for graphic codes of CD graphics. That is, the codes constituting these subcodes are unnecessary codes for transmitting the audio signal, and the present invention utilizes them. As described above, the current CD format has been described first.

FIG. 1 (c) shows a data format realized by diverting the above-described subcode.
In FIG. 1A, the code is placed at the same position as the code shown in FIG. 1B. Therefore, the data format (that is, the transmission format of the digital audio signal) according to the present invention has the same format as the data format of the current CD, except that the volume control related data is multiplexed using the subcode portion. Will be used.

In FIG. 1 (c), a code A consisting of 1 bit
Is a channel selection signal, and the fact that the code A is 0 indicates that the following code B and code C are valid for Lch (left channel).
Is 1 indicates that the following code B and code C are valid for Rch (right channel).

The code B consisting of 1 bit is a signal for controlling ON / OFF of the power supply of the audio amplifier circuit for driving the speaker on the receiving side, 1 being ON and 0 being OFF. The code C composed of 6 bits is a control signal for controlling the volume of an audio amplifier circuit for driving a speaker on the receiving side, and controls 64 steps from a minimum of 000000 to a maximum of 111111.

These 8-bit codes of A, B and C are multiplexed in place of the sub-code, and the data and parity bits are assigned an audio signal, thus forming the format of the transmitted audio signal according to the present invention. It is done.

As described above, according to the transmission method according to the format according to the present embodiment, the digital audio signal is multiplexed with the respective control signals of the volume control signal, the power supply control signal, and the L / R channel identification signal on the receiving side, and the optical spatial transmission is performed. Can be transmitted with suitable EFM modulation. Therefore, volume control can be performed on the receiving side, and the audio output level can be adjusted without increasing the ratio of the quantization error to the audio output level and deteriorating audio performance.

Also, when the user controls with the remote control,
Normally, the CD disk playback device and the playback audio signal transmission device are integrated and installed adjacent to each other. Therefore, the user only has to operate the remote controller toward the integrated device. After the remote control is operated toward, further troublesome operations such as operating the power supply of the audio amplification circuit and operating the remote control for controlling the volume are not required for the receiving side having the speaker.

 Next, another embodiment of the present invention will be described with reference to FIG.

FIG. 2 (a) shows the Q according to the current CD format.
The format of the code. That is, as shown in FIG. 1, the Q code has a format of 1 bit per frame, and collects 98 frames of Q codes, that is, 98 bits, and further as shown in FIG. Configure the format.

Here, S0 and S1 are sync patterns indicating the beginning of the format, CONTROL is a control code for selecting an audio mode consisting of 4 bits, and ADR is a mode of the format of DATA-Q consisting of 4 bits. DATA-Q is a song number, a time code, and the like used for display including 72 bits. CRC
Is an error detection code for CONTROL, ADR, DATA-Q consisting of 16 bits.

In a normal CD signal processing LSI, an error detection operation is performed, and a signal indicating whether the 80-bit data of CONTROL, ADR, DATA-Q is correct or incorrect, and the 80-bit data are output together.

FIG. 2 (b) shows a data format for realizing the transmission system according to the present invention by using the conventional format shown in FIG. 2 (a). This format corresponds to a system for transmitting a digital audio signal to two receiving devices for Rch and Lch each provided with a speaker and an audio amplifier circuit for each frame.

One block is formed by 98 frames for each bit at the position of Q shown in FIG. 1 (b).
The format of FIG. 2B is configured according to the present invention.

Here, S0 and S1 are the same sync patterns as in the CD format. The Lch power control signal is 1 bit, and is a power control code for the audio amplifier circuit of the Lch side receiver.
ON, 1 is OFF. The Rch power control signal is a similar power control signal for Rch. Lch volume control signal (39
Bits) it may be up to the control of 2 ³⁹ stage 39-bit control signal for volume control of the audio amplifier circuit of the Lch receiver.

The Rch volume control signal is related to Rch,
It is the same as the volume control signal. The CRC code is a 16-bit error detection code applied to a total of 80-bit codes of the L and R power control signals and the L and R volume control signals, and follows a generating polynomial in the CD format.

The 80-bit format other than the CRC code and the S0 and S1 codes is not limited to the above format as long as the L and R volume control signals and the L and R power control signals are recorded.

As described above, according to the present embodiment, a digital audio signal can be multiplexed with a volume control signal on the receiving side, and can be transmitted after being subjected to EFM modulation suitable for optical space transmission. Therefore, it is possible to modulate the audio level without deteriorating the audio performance due to an increase in the ratio of the quantization error.

The current CD signal processing LSI has an EFM demodulation function and an audio data correction function, and has a function of separating a normal Q code and outputting it together with a correct / incorrect code. Therefore, transmitted
Since the present invention is designed to demodulate the EFM signal and separate the volume control code and the power control code from the digital audio signal, the signal processing for the current CD player is performed.
Processing can be performed using LSI.

In response to a request to also transmit a song number and a time code, the Q code is transmitted using the current CD format shown in FIG. 2 (a), and the volume control signal is transmitted as shown in FIG. 2 (b). The signal constitutes the sub-code of FIG. 1 (b)
What is necessary is just to send using the code of one of P, R-W code.

Next, an embodiment of the transmitting apparatus used for carrying out the present invention will be described with reference to FIG. FIG. 3 shows, in other words, a block diagram of the optical space transmission transmitting apparatus according to the present invention.

In the figure, 1 is a digital audio signal input terminal, 2 is a data bus, and 3 is an RA used for temporarily storing data.
M, 4 is a RAM control circuit that controls the address of the RAM, 5 is an error correction circuit that generates an error correction code, 6 is an EFM modulation circuit that performs EFM modulation, and 7 is a data transmission rate 1 / of the EFM signal.
An edge signal generation circuit that converts a T (bit / sec) into a pulse having a pulse width of Tsec in response to the rising and falling of the EFM signal, and 8 is an optical signal that converts an electric signal into an optical signal. An electric conversion circuit, 9 is a sub-code processing means, 10 is a code converter, 11 to 15 are power supplies, and switches for volume control.

The quantized and discretized digital audio signal is
Once stored in the RAM 3 via the data bus 2 from the digital audio signal input terminal 1 and read out, an error correction circuit 5 generates an error correction code via the data bus 2 and outputs the error correction code together with the digital audio data. Write RAM3.

The written data is stored in a RAM by the RAM control circuit 4.
By controlling the address 3, data distribution (interleaving) is performed. The data is further sent to the error correction circuit 5, where an error correction code is generated and added again, and then the EFM modulation circuit 6 is transmitted via the data bus 2. Sent to

On the other hand, volume control and power supply control of the audio amplifier circuit on the receiving side are first operated by the switches 11 to 15. Switch 11 is used to turn on / off the power supply of the audio amplifier on the receiving side, and switch 12
Is the volume up of the audio amplifier circuit, the switch 13 is the volume down, the switch 14 is the L side shift of the L and R volume balance, the switch 15 is the R side shift, and according to the input of the switches 11 to 15, the code converter 10 is For example, FIG.
, A channel control signal A, a power control signal B, and a volume control signal C.

The signal from the code converter 10 is sent to the subcode processing means 9 and sent to the EFM modulation circuit 6 in accordance with the timing at which the subcodes P to W are multiplexed in the CD format. From the EFM modulation circuit 6, a signal in which the digital audio signal and the reception side control code are multiplexed is EFM-modulated and sent to the edge signal generation circuit 7.

After being further converted into an etch signal by the edge signal generation circuit 7, it is converted into light by the electro-optical converter 8 and transmitted spatially.

As described above, according to the optical space transmission apparatus according to the present embodiment, the volume control signal of the power amplifier circuit on the receiving side and the power control signal are multiplexed with the digital audio signal and transmitted with EFM modulation suitable for optical space transmission. Can be. Therefore,
A digital optical space transmission system capable of adjusting the audio output level on the receiving side without deteriorating the audio performance can be configured.

Next, an embodiment of a receiving apparatus used for implementing the present invention will be described with reference to FIG. FIG. 4 shows, in other words, a block diagram of an optical space transmission / reception apparatus according to the present invention.

In FIG. 4, reference numeral 20 denotes a space optical transmission transmitter, which is the same as the space optical transmission transmitter shown in FIG.
Reference numeral 21 denotes a transmission side system in which a digital audio signal source is added to the optical space transmission device 20. 101 and 201 are light receiving circuits for converting an optical signal into an electric signal and further reproducing an EFM signal; 102 and 202 are signal processing circuits for reproducing a digital audio signal and separating a control signal from the EFM signal;
3,203 is a digital / analog conversion circuit (DA conversion circuit), 104,204 is an attenuator for adjusting the audio signal reproduction level, 105,205 is an amplification circuit, 106,206 is a speaker, 10
7,207 is a decoder circuit, and 108,208 are switches.

101 to 108 constitute the receiving apparatus 100, and 201 to 208 constitute the receiving apparatus 200. The optical space transmission receiver is L, R2
Two receiving devices 10 for receiving each channel from the transmitting side system 21 which transmits the signals of the channels in a time-division multiplex manner.
Consists of 0,200. Hereinafter, the operation of the receiving apparatus will be described along the flow of signals.

On the transmitting side system 21 side, the L and R 2ch audio signals are time-division multiplexed from the optical space transmission transmitting
After performing M modulation and edge signal generation, it is further optically converted and spatially transmitted.

Note that the volume control signal and the channel selection signal are multiplexed on the EFM signal as described with reference to FIG.

Through the space, the signal transmitted to the receiving apparatus 100 performs optical-electric conversion and reproduction of the EFM signal in the light receiving circuit 101, and reproduces the reproduced EFM signal in the signal processing circuit 102, including separation of control signals, including error correction. The reproduced digital audio signal is reproduced. The digital audio signal is sent to a DA converter 103, and the separated control signal is sent to a decode circuit 107.
Sent to

In the decoding circuit 107, a signal for setting the receiving apparatus 100 to Lch or Rch by the switch circuit 108 is input. When set to Lch, the decoding circuit 107 controls the DA conversion circuit 103 to operate when the Lch signal is input to the DA conversion circuit 103, and outputs the volume control signal to which the Lch selection signal is added. Decode and control the attenuator 104. The same applies to the case where Rch is set. DA
The audio signal converted to an analog signal by the conversion circuit 103 is controlled in the amount of attenuation by the attenuator 104,
And is reproduced from the speaker 106.

On the other hand, on the receiving device 200 side, the switch 208
8 is set in the opposite direction, and processing is performed on the signal of the channel opposite to that of the receiving device 100 side. All processes are the same except that the channels for performing reproduction and control are different. Therefore, it is possible to configure a digital wireless stereo speaker system in which the user can easily control the volume without deteriorating the audio performance.

Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 5 shows a digital audio interface format, and FIG. 6 shows an improved digital audio interface format, which enables volume control on the receiving device side.
3 is a format according to the present invention.

First, the digital audio interface will be described with reference to FIG.

FIG. 5A shows a format for one word of audio data, and 192 words are collected in one block to constitute the format shown in FIG. 5B.

Bit positions 0 to 3 in FIG. 5A indicate a synchronization preamble, and are composed of three types of B, M, and W. B indicates that the added word is the head of one block shown in FIG. 5 (b). At the same time, when audio data is viewed as signals other than the A channel and the A channel, it is a signal of the A channel. Indicates that M
Indicates that the audio data of the added word is an A channel signal and is not the head of a block,
W indicates that the audio data of the added word is a signal other than the channel A.

5 is normally set to zero. The audio data shown in FIG. 5A is 20 bits of 8 to 27 bits. If the digital audio data to be transmitted is 20 bits or less, the data is rear-justified, and the LSB is set to 0.
The V bit in FIG. 5 (a) is a parity flag indicating an error state at the time of reproduction of the transmitting apparatus, the U bit is a bit for transmitting user data (subcode), the C bit is copy inhibition, This is a channel status indicating the type of a reproducing apparatus of the digital audio signal to be permitted and transmitted, and the P bit is an even parity for all bits in one word excluding the synchronous amble.

FIG. 6 shows a format according to the present invention in which U bits of the digital audio interface format shown in FIG. 5 are used for volume control on the receiving device side. FIG. 6 is a diagram in which one U-bit data is taken out for each word and arranged from the head of the block in FIG. 5 (a). Therefore, the number given at the top of FIG.
It shows the same frame number as in FIG.

The example of this format shows a case of 2ch audio data. The U bit of frame number 0 is ch1
A control signal for performing ON / OFF control of the power supply of the amplifier circuit of the receiving device on the side, and frame numbers 1 to 8 are control signals for performing volume control of the receiving device of ch1. The ch1 here is the fifth
This corresponds to channel A in the figure. The U bit of frame number 9 is the O power supply of the amplifier circuit of the receiving device on the ch2 side.
Control signals for performing N / OFF control, and frame numbers 10 to 17 are volume control signals for performing volume control of the receiving device on the ch2 side.

The ch2 here corresponds to a channel other than the channel B in FIG. U bit data of frame numbers 18 to 191 are not specified. Further, the number of bits of each volume control signal and the frame number to which the U bit of the volume control signal and the ON / OFF control signal are applied are not limited to this example.

As described above, in the present embodiment, when configuring a wired digital stereo speaker system in which the transmission device and the reception device are connected in a wired manner, not in a wireless space, the user can easily perform volume control without deterioration in audio performance. A transmission format can be provided.

Next, with reference to FIG. 7, a description will be given of a transmission / reception apparatus as an embodiment of the present invention using the above-described wired connection. FIG. 7 is a block diagram showing a wired digital audio data transmission system according to the present invention.

In FIG. 7, reference numeral 31 denotes a digital audio signal input terminal, and reference numeral 30 denotes a digital audio interface transmission device, which transmits digital audio data in accordance with the format shown in FIG.

Reference numeral 32 denotes a volume data generation device which generates a volume control signal shown in FIG. 301 and 401 are signal processing circuits for reproducing digital audio data from transmission data and separating control signals, 302 and 402 are DA conversion circuits, 303 and 403 are attenuators for adjusting audio signal reproduction levels, 304 and 404 are amplification circuits, and 305 and 405 are speakers. 306,40
6 is a decoder circuit, and 307 and 407 are switches.

301 to 307 constitute the receiving device 300, and 401 to 407 constitute the receiving device 400. This system comprises a transmitting system for transmitting the signals of the L and R2 channels in a time-division multiplex manner, and two receiving devices 300 and 400 for receiving each channel. Hereinafter, the operation of the present system will be described along the flow of signals.

The digital audio signal input from the digital audio signal input terminal 31 is sent to the digital audio interface transmitting device 30. According to the format of FIG. 6, the volume control signal generated by the volume data generating device 32 is inserted into the U bit, and transmitted to the receiving devices 300 and 400 via the cable.

The signal transmitted to the receiving device 300 is a received signal processing circuit 3
01, the digital audio data is converted to the DA conversion circuit 30
2, and the separated control signal is sent to the decoding circuit 306. In the decoding circuit 306, a signal to be set to Lch or Rch by the receiving device 300 is input by the switch circuit 307.

When set to Lch, the decoding circuit 306 outputs
When it is input to the A conversion circuit 302, it controls the DA conversion circuit 302 to operate, decodes the Lch side volume control signal, and controls the attenuator 303. The same applies to the case where Rch is set. The audio signal converted into an analog signal by the DA conversion circuit 302 is subjected to attenuation control by an attenuator 303, and then is amplified by an amplifier circuit 304, and is amplified by a speaker 305.
Will be played more.

On the other hand, on the receiving device 400 side, the switch 407 is
And the processing is performed on the signal of the channel opposite to that of the receiving device 300. All the processes are the same except that the channels for reproduction and control are different. Therefore, it is possible to configure a wired digital stereo speaker system in which the user can easily control the volume without deteriorating the audio performance.

〔The invention's effect〕

According to the present invention, a reproduction performance designating code for realizing reproduction in accordance with a reproduction performance desired by a user, such as a volume control signal of a receiving side audio amplifier circuit, is used as a reproduction performance control code in a digital audio signal. It can be multiplexed and transmitted with EFM modulation suitable for optical space transmission (although the invention is not limited to this, and a wired system is also possible). Therefore, for example, the audio level can be adjusted to a level desired by the user and reproduced without causing deterioration in audio performance due to an increase in the ratio of the quantization error. In addition, when the user controls with the remote controller, the trouble of pointing the remote controller to the receiving side having the speaker each time can be saved.

[Brief description of the drawings]

FIG. 1 (a) is an explanatory diagram showing a current CD format, FIG. 1 (b) is an explanatory diagram showing a sub-code therein before EMF modulation, and FIG. 1 (c) is a diagram according to the present invention. FIG. 2 (a) is an explanatory diagram showing a data format to be placed at the position of a subcode, FIG. 2 (a) is an explanatory diagram of a Q code format according to the current CD format, and FIG.
FIG. 3 is an explanatory diagram showing a data format to be put in the position of a code format according to the present invention; FIG. 3 is a block diagram showing an embodiment of a transmitting device used when implementing the present invention;
FIG. 4 is a block diagram showing an embodiment of a receiving apparatus used in carrying out the present invention, FIGS. 5 (a) and 5 (b) are explanatory diagrams of the format of a digital audio interface, and FIG. FIG. 7 is an explanatory diagram showing a data format to be put on a digital audio interface format, and FIG. 7 is a block diagram showing an embodiment of a transmitting / receiving device used when implementing the present invention in a wired system. Description of symbols 3 ... RAM, 4 ... RAM control circuit, 5 ... Error correction circuit,
6 EFM modulation circuit, 7 Edge signal generation circuit, 8
... Electrical-optical converter, 9 ... Subcode processing means, 10 ...
Code converter, 11 ~ 15 …… Switch

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takao Arai 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Home Appliance Research Laboratory, Hitachi, Ltd. (56) References JP-A-1-160225 (JP, A) JP-A Sho 61-30140 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04B 14/00-14/06 G11B 20/12

Claims (7)

(57) [Claims] A digital audio signal is serially transmitted from a source to a receiving side, and when reproduced, a reproduction performance designating code for realizing reproduction in accordance with a reproduction performance desired by a user is provided. A method of serially transmitting an audio signal to be multiplexed and transmitted with audio signal data at a source as a reproduction performance control code, wherein a user sets the reproduction performance control code;
Multiplexing and transmitting the set reproduction performance control code to digitized audio signal data to be transmitted, and transmitting the audio signal serially. 2. The audio signal serial transmission method according to claim 1, wherein said reproduction performance control code comprises a control code for specifying an audio signal level at the time of reproduction on a receiving side. Serial transmission method. 3. The serial transmission method of an audio signal according to claim 1, wherein the reproduction performance control code is a level control code for specifying an audio signal level at the time of reproduction on the receiving side, and the audio signal received on the receiving side. A power supply control code for controlling on / off of a power supply of an audio amplifier circuit for converting data into an analog signal and then amplifying the data, and a serial transmission method for an audio signal. 4. The serial transmission method of an audio signal according to claim 1, wherein when the digitized audio signal to be transmitted conforms to a compact disk type CD format, the reproduction performance control code is converted to a CD format.
A serial transmission method of an audio signal, which is multiplexed in a subcode area of a format, and subjected to EFM modulation before transmission. 5. The method for serially transmitting an audio signal according to claim 3, wherein when the digitized audio signal to be transmitted conforms to a compact disk type CD format, the level control code and the power control code are: A serial transmission method of an audio signal, which is multiplexed in a sub-code area of a CD format and subjected to EFM modulation before transmission. 6. A transmitter for serially transmitting a digitized audio signal, comprising: an error correction means for adding an error correction code to a digitized audio signal to be transmitted in accordance with a CD format; CD with the data
Data distribution means to distribute (interleave) according to the format, and subcode area of CD format,
Subcode processing for multiplexing the reproduction performance control code with digital audio signal data to be transmitted by adding a reproduction performance designation code for realizing reproduction in accordance with the reproduction performance desired by the user as a reproduction performance control code Means, means for performing EFM modulation on the digital audio signal data and the reproduction performance control code in accordance with the CD format, and thereafter, electrical / optical conversion means for performing electrical / optical conversion and outputting. A transmission device characterized by the above-mentioned. 7. A transmitting apparatus for serially transmitting a digitized audio signal, comprising: an error correcting means for adding an error correcting code to a digitized audio signal to be transmitted in accordance with a CD format; CD with the data
Data distribution means to distribute (interleave) according to the format, and subcode area of CD format,
Subcode processing means for multiplexing digital audio signal data to be transmitted by carrying a volume control signal for controlling an audio reproduction level and a power supply control signal for controlling on / off of a power supply of a reception side audio amplification circuit;
Means for performing EFM modulation on the digital audio signal data and control signal data in accordance with the CD format, and thereafter, electrical / optical conversion means for performing electrical / optical conversion and outputting. Transmitting device.