JP2011066548A - Electronic equipment and data transmission method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electronic equipment transmitting the audio data of a base band with high quality. <P>SOLUTION: In a sampling-rate-converter, the sampling frequency of the audio data of the base band supplied from a decoder is matched with the rate of a second audio master clock generated from the frequency signals of an exclusive crystal oscillator provided near a second transmitter. Also, in the second transmitter, a pixel clock is generated from a second video master clock generated from the frequency signals of the exclusive crystal oscillator and transmitted to external equipment. Since the transmission path length of the clock whose source is the frequency signal of the exclusive crystal oscillator may be short compared to the transmission path length of the clock whose source is the frequency signal of an oscillation part inside the decoder, the influence on the clock, of high frequency noise inside the electronic equipment is reduced, and the amount of jitters generated in the pixel clock to be transmitted to the external equipment is reduced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic device and a data transmission method for transmitting video data and audio data by HDMI.

  In recent years, HDMI (High Definition Multimedia Interface) (registered trademark) is becoming widespread as a communication interface that transmits uncompressed (baseband) video data and audio data accompanying the video data at high speed. For example, HDMI can send high-quality video data from a Blu-ray recorder, set-top box, or other AV (Audio Visual) source to a television receiver, projector, monitor, or the like. For example, Patent Document 1 describes the details of the HDMI standard.

  In HDMI, two-way communication is performed via an HDMI cable between an HDMI source provided in an electronic device that transmits video data and audio data and an HDMI sink provided in a receiving electronic device. The HDMI source is provided with a transmission unit called “transmitter”, and the HDMI sink is provided with a reception unit called “receiver”. Video data, audio data, control data, pixel clocks, and the like are transmitted from the transmitter to the receiver using a plurality of channels. The control data includes, for example, a vertical synchronization signal (V_Sync), a horizontal synchronization signal (H_Sync), and frequency division ratio data between a pixel clock that is a video master clock and an audio master clock.

  The receiver receives video data, audio data, and control data transmitted from the transmitter through a plurality of channels in synchronization with a pixel clock transmitted from the transmitter through the TMDS clock channel. The receiver separates the received video data, audio data, and control data, and supplies the separated video data, the vertical synchronization signal (V_Sync), the horizontal synchronization signal (H_Sync), and the like in the control data to the video processing unit. . The video processing unit performs processing so that the video data supplied from the receiver is displayed on the display unit in accordance with the vertical synchronization signal (V_Sync) and the horizontal synchronization signal (H_Sync) supplied from the receiver.

  The receiver supplies the separated audio data to the audio processing unit, and supplies the pixel clock transmitted through the TMDS clock channel and the division ratio data in the control data to the audio clock reproduction unit. The audio clock reproduction unit generates an audio master clock from the pixel clock and frequency division ratio data supplied from the receiver and supplies the audio master clock to the audio processing unit. The audio processing unit restores the analog audio signal from the audio data supplied from the receiver in synchronization with the audio master clock supplied from the audio clock reproduction unit, and supplies the analog audio signal to the audio output unit.

WO2002 / 078336 (PCT / JP02 / 02824)

  As described above, the HDMI sink receives video data in synchronization with the pixel clock transmitted through the TMDS clock channel, and audio data in synchronization with the audio master clock obtained by dividing the pixel clock. Is restored to the original analog signal waveform. For this reason, the following problems may occur.

  The pixel clock is generated by a transmitter in the HDMI source based on a video master clock (video clock) supplied from a decoder that decodes compression-coded video data and audio data to obtain baseband data. And transmitted toward the HDMI sink. However, since the signal transmission path from the decoder to the transmitter is exposed to high frequency noise in the electronic equipment, the video master clock transmitted through the signal transmission path is subject to fluctuations in the time axis due to the influence of the high frequency noise (jitter) ) May occur. Therefore, a pixel clock including a jitter component is transmitted from the transmitter to the HDMI sink, and an electronic device having the HDMI sink may adversely affect the reception of video data and the restoration of audio data to an analog signal waveform.

  Here, comparing the effects of pixel clock jitter on video playback with the effects of pixel clock jitter on analog signal waveform recovery from audio data, auditory information is compared to visual information, It can be said that it is easily perceived by the user and has a high influence on the quality of media playback.

  In view of the circumstances as described above, an object of the present invention is to provide an electronic device and a data transmission method capable of transmitting baseband audio data with high quality.

In order to achieve the above object, an electronic device according to the present invention includes a decoding unit, a first transmission unit, a second oscillator, an audio clock generation unit, a signal generation unit, and a second transmission unit. It has.
The decoding unit includes a first oscillator that oscillates a predetermined frequency signal, generates a first video master clock and a first audio master clock from the frequency signal of the first oscillator, and Using the first video master clock, the compressed and encoded video data is decoded to output baseband video data, which is compressed and encoded using the first audio master clock. Decodes the audio data and outputs baseband audio data.
The first transmission unit can transmit the baseband video data and audio data and a pixel clock corresponding to the master clock for the first video to a device connected to the outside using a plurality of channels. .
The second oscillator oscillates a predetermined frequency signal.
The audio clock generation unit generates a second audio master clock from the frequency signal of the oscillator.
A signal generation unit configured to convert a sampling frequency of the baseband audio data output from the decoding unit in accordance with the generated second audio master clock; and an oscillation of the second oscillator A master clock for the second video is generated from the frequency.
The second transmission unit uses at least the audio data output from the conversion unit and converted from the sampling frequency and a pixel clock corresponding to the second video master clock using the plurality of channels. Can be transmitted to an externally connected device.

  In the present invention, the conversion unit matches the sampling frequency of the baseband audio data supplied from the decoding unit with the rate of the master clock for the second audio generated from the frequency signal of the second oscillator. The second transmitter generates a pixel clock from the second video master clock generated from the frequency signal of the second oscillator, and transmits the pixel clock to an external device. Here, the second oscillator is arranged in the vicinity of the second transmission unit, and is arranged at a position closer to the second transmission unit, so that the frequency signal of the first oscillation unit in the decoding unit is the source of the clock. Compared with the transmission path length, the transmission path length of the clock whose source is the frequency signal of the second oscillating unit can be shortened. As a result, the influence of the high frequency noise in the electronic device on the clock is reduced, and the amount of jitter generated in the pixel clock transmitted to the external device can be reduced. Therefore, audio data can be transmitted from the second transmission unit to an external device with high quality.

  In the present invention, the signal generation unit may replace the baseband video data output from the decoding unit to the first transmission unit with a video of “0” synchronized with the master clock for the second video. Data is generated and supplied to the second transmission unit together with the second video master clock. The second transmission unit includes the audio data obtained by converting the sampling frequency, and the second transmission unit. In addition to the pixel clock corresponding to the video master clock, “0” video data synchronized with the second video master clock may be transmitted to an externally connected device.

  In the present invention, the decoding unit further outputs a first bit clock and a first LR clock related to the baseband audio data, and the conversion unit outputs the first bit clock output from the decoding unit. Are converted to the second bit clock and the second LR clock based on the generated second video master clock, and the second transmission unit converts the second clock and the first LR clock into the second bit clock and the second LR clock. The audio data output by the conversion unit may be transmitted to an externally connected device according to the second bit clock and the second LR clock generated by the conversion unit.

  As described above, according to the present invention, baseband audio data can be transmitted with high quality.

It is a block diagram which shows the structure of the data transmission system using the electric equipment which concerns on this Embodiment. It is a block diagram which shows the structure of the peripheral circuit of the 1st transmitter in a HDMI source, and a 2nd transmitter. It is a figure which shows the connection form of the apparatus in the data transmission system using the electric equipment which concerns on this Embodiment. It is a figure which shows another connection form of the apparatus in the data transmission system using the electric equipment which concerns on this Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration of a data transmission system using an electrical device according to an embodiment.

<First Embodiment>
[System configuration]
As shown in FIG. 1, the data transmission system 100 includes a first electronic device 10 (electronic device) and a second electronic device 20 (devices connected to the outside) connected to each other via an HDMI cable 1. Here, the first electronic device 10 is the data transmission side, and the second electronic device 20 is the data reception side. A portion that performs processing for transmitting data via the HDMI cable 1 is referred to as “HDMI source”, and a portion that performs processing for receiving data via the HDMI cable 1 is referred to as “HDMI sink”. That is, in the illustrated example, the first electronic device 10 includes the HDMI source 11, and the second electronic device 20 includes the HDMI sink 21.

  More specifically, the first electronic device 10 incorporating the HDMI source 11 more specifically decodes the compression-coded video data and audio data to generate uncompressed (baseband) video data and audio data. A device including a (decoding unit). For example, various players such as a player that decodes video data and audio data recorded on a portable medium such as a DVD or a Blu-ray disc, terrestrial digital broadcast, CS (Communication Satellite) digital broadcast, BS (Broadcasting Satellite) digital broadcast A broadcast receiver that receives and decodes video data and audio data broadcast on a broadcast wave from a broadcasting station in the form of a broadcast, and receives and decodes video data and audio data transmitted through a network such as the Internet An information processing apparatus is exemplified.

  The HDMI source 11 includes a first transmitter 12 (first transmission unit) and a second transmitter 13 (second transmission unit).

  The first transmitter 12 converts the baseband video pixel data supplied from the decoder into corresponding differential signals, and three TMDS (Transition Minimized Differential Signaling) channels # 0, # 1, # in the active video area. 2 is transmitted to the HDMI sink 21. The active video area is a section obtained by removing a horizontal blanking section and a vertical blanking section from a section from one vertical synchronizing signal to the next vertical synchronizing signal.

  The first transmitter 12 converts the baseband audio data and control data supplied from the decoder into corresponding differential signals, and the three TMDS channels # 0 in the horizontal blanking interval or the vertical blanking interval. , # 1, # 2 to the HDMI sink 21. Here, the baseband audio data is audio data accompanying the baseband video data supplied from the decoder.

  Further, the first transmitter 12 transmits a pixel clock synchronized with the pixel data transmitted through the three TMDS channels # 0, # 1, and # 2 to the HDMI sink 21 through the TMDS clock channel. Here, in one TMDS channel #i (i = 0, 1, 2), 10-bit pixel data is transmitted during one pixel clock. The first transmitter 12 transmits the video clock (first video master clock) supplied from the decoder as it is to the HDMI sink 21 as a pixel clock.

  The second transmitter 13 performs sampling and sampling in accordance with an audio master clock (second audio master clock) generated from an oscillation frequency signal of a dedicated crystal oscillator (second oscillator) disposed in the vicinity. A differential signal corresponding to the audio data whose rate is converted is transmitted to the HDMI sink 21. The second transmitter 13 transmits a differential signal corresponding to “black (0)” to the HDMI sink 21 instead of the baseband video data supplied from the decoder. Further, the second transmitter 13 transmits the video clock (second video master clock) generated from the oscillation frequency signal of the dedicated crystal oscillator as a pixel clock to the HDMI sink 21 through the TMDS clock channel. The configuration of the peripheral circuit of the second transmitter 13 including the crystal oscillator will be described in detail later.

  In addition to the three TMDS channels # 0 to # 2 and the TMDS clock channel, the transmission channel of the HDMI system comprising the HDMI source 11 and the HDMI sink 21 is a transmission channel called a DDC (Display Data Channel) or CEC line. There is.

  The DDC includes two signal lines (not shown) included in the HDMI cable 1 and is used by the HDMI source 11 to read E-EDID (Enhanced Extended Display Identification Data) from the HDMI sink 21. That is, the HDMI sink 21 has an EDID ROM (EDID ROM (Read Only Memory)) that stores E-EDID, which is information related to its settings and performance, in addition to the receiver 22. The HDMI source 11 reads the E-EDID from the EDIDROM of the HDMI sink 21 via the DDC, and the setting and performance of the HDMI sink 21 based on the E-EDID, that is, for example, the HDMI sink 21 (an electronic device having the HDMI sink 21) It recognizes the corresponding video format (profile), such as RGB (Red, Green, Blue), YCbCr4: 4: 4, YCbCr4: 2: 2. Similarly to the HDMI sink 21, the HDMI source 11 can also store E-EDID and transmit the E-EDID to the HDMI sink 2172 as necessary.

  The CEC line is composed of one signal line (not shown) included in the HDMI cable 1 and is used for bidirectional communication of control data between the HDMI source 11 and the HDMI sink 21. Also, the HDMI source 11 and the HDMI sink 21 transmit frames conforming to, for example, IEEE (Institute of Electrical and Electronics Engineers) 802.3 to the HDMI sink 21 and the HDMI source 11 via the DDC or CEC line. Bidirectional IP communication can be performed. Further, the HDMI cable 1 includes a signal line connected to a pin called “Hot Plug Detect”, and the HDMI source 11 and the HDMI sink 21 use this signal line to create a new electronic device, that is, HDMI. The connection of the sink 21 or the HDMI source 11 can be detected.

Next, the configuration of the second electronic device 20 incorporating the HDMI source 11 will be described.
The second electronic device 20 incorporating the HDMI source 11 is a device capable of processing baseband video data and displaying it on a display unit, or processing baseband audio data and outputting sound. For example, a television receiver, a projector, a monitor or the like.

  The receiver 22 transmits video data and audio data transmitted from one transmitter connected to the first transmitter 12 or the second transmitter 13 through the HDMI cable 1 through the three TMDS channels # 0, # 1, and # 2. And the differential signal of control data is received and demodulated. At this time, the receiver 22 receives video data, audio data, and control data in synchronization with the pixel clock transmitted from the one transmitter through the TMDS clock channel. The receiver 22 separates the demodulated video data, audio data, and control data, and supplies the separated video data, the vertical synchronization signal (V_Sync) and the horizontal synchronization signal (H_Sync) in the control data to the video processing unit 23. The receiver 22 supplies the separated audio data to the audio processing unit 24, and supplies the pixel clock transmitted through the TMDS clock channel and the division ratio data in the control data to the audio clock reproduction unit 26, respectively.

  The video processing unit 23 performs processing so that the video data supplied from the receiver 22 is displayed on the display unit 25 in accordance with the vertical synchronization signal (V_Sync) and the horizontal synchronization signal (H_Sync).

  The audio clock reproduction unit 26 generates an audio master clock from the pixel clock and frequency division ratio data supplied from the receiver 22 and supplies the audio master clock to the audio processing unit 24. More specifically, the audio clock reproduction unit 26 has a frequency divider, and generates a master clock for audio by dividing the pixel clock by the frequency division ratio data with this frequency divider. Here, the frequency division ratio data may be obtained through DDC.

  The audio processing unit 24 demodulates the audio data supplied from the receiver 22 in synchronization with the audio master clock supplied from the audio clock reproduction unit 26, and supplies an analog audio signal to the audio output unit 27. As a result, audio corresponding to the analog audio signal is output from the audio output unit 27.

[Peripheral circuits of the first and second transmitters 12 and 13]
Next, peripheral circuits of the first transmitter 12 and the second transmitter 13 in the HDMI source 11 will be described with reference to FIG.

  In the HDMI source 11, as peripheral circuits of the first transmitter 12 and the second transmitter 13, a decoder 14 (decoding unit), a crystal oscillator 15 (second oscillator), a clock generation unit 16 (audio clock generation unit) A sampling rate converter 17 (conversion unit), a signal generation unit 18 (signal generation unit), and the like are provided. The crystal oscillator 15, the clock generator 16, the sampling rate converter 17, and the signal generator 18 are arranged in a second manner so that the influence of high frequency noise in the first electronic device 10 can be minimized. The transmitter 13 is provided in the vicinity.

  The decoder 14 uses a video master clock (first video master clock) generated from an oscillation frequency signal of a crystal oscillator (not shown) (first oscillator) incorporated in the decoder 14 to generate video data. The baseband video data (V_DATA) is output to the first transmitter 12. The decoder 14 generates a video clock (V_CLK) from a video master clock (first video master clock), and generates a video vertical synchronization signal (V_Sync) and a horizontal synchronization signal (H_Sync). The video clock (V_CLK), the vertical synchronizing signal (V_Sync), and the horizontal synchronizing signal (H_Sync) are supplied to the first transmitter 12 together with the baseband video data (V_DATA).

  The decoder 14 uses an audio master clock (first audio master clock) generated from an oscillation frequency signal of a crystal oscillator (not shown) (first oscillator) incorporated in the decoder 14. The compressed and encoded audio data is decoded, and baseband audio data (A_DATA) is output to the first transmitter 12 and the second transmitter 13. The decoder 14 generates a bit clock (BCK) and an LR clock (LRCK) from the audio master clock (first audio master clock), and generates the first clock and the baseband audio data (A_DATA) together with the first transmitter. 12 and the second transmitter 13. Further, the decoder 14 supplies an audio master clock (MCK) to the first transmitter 12.

  Thus, the baseband video data (V_DATA), the video vertical synchronization signal (V_Sync), and the horizontal synchronization signal (H_Sync) are not supplied from the decoder 14 to the second transmitter 13. Only the audio data (A_DATA) and the bit clock (BCK) and LR clock (LRCK) necessary for transmission of the audio data (A_DATA) are supplied from the decoder 14 to the second transmitter 13.

  The crystal oscillator 15 is a crystal oscillator dedicated to the second transmitter 13 and is independent of the crystal oscillator in the decoder 14. The clock generator 16 generates an audio master clock (second audio master clock) from the oscillation frequency signal of the crystal oscillator 15 and supplies it to the sampling rate converter 17.

  The sampling rate converter 17 uses the sampling rate of the baseband audio data (A_DATA) supplied from the decoder 14 as the audio master clock (second audio master clock) supplied from the clock generator 16. ) And is supplied to the second transmitter 13. The sampling rate converter 17 uses the bit clock (BCK) and LR clock (LRCK) supplied from the decoder 14 as the audio master clock (second audio master supplied from the clock generator 16). The bit clock (BCK) and the LR clock (LRCK) with reference to the clock) are substituted and supplied to the second transmitter 13.

  The signal generator 18 generates a video clock (V_CLK) (second video master clock), a video vertical synchronization signal (V_Sync), and a horizontal synchronization signal (H_Sync) from the oscillation frequency signal of the crystal oscillator 15, Supply to the second transmitter 13.

  The second transmitter 13 generates a differential signal corresponding to the baseband audio data (A_DATA) supplied from the sampling rate converter 17 in synchronization with the bit clock (BCK) and the LR clock (LRCK). Serial transmission to the HDMI sink 21 is performed using the three TMDS channels # 0, # 1, and # 2. At the same time, the second transmitter 13 transmits the video clock (V_CLK) supplied from the signal generator 18 as a pixel clock to the HDMI sink 21 via the TMDS clock channel, and the video data (V_DATA) is all “black ( 0) "is serially transmitted to the HDMI sink 21 through the three TMDS channels # 0, # 1, and # 2.

[Connection and operation of electronic devices]
Next, a connection mode and operation between the first electronic device 10 as the HDMI source 11 and the second electronic device 20 as the HDMI sink 21 of the data transmission system 100 of the present embodiment will be described.

  The first electronic device 10 as the HDMI source 11 is provided with a first HDMI connector 19A corresponding to the first transmitter 12 and a second HDMI connector 19B corresponding to the second transmitter 13. Here, as shown in FIG. 3, when the second electronic device 20 such as a television receiver capable of outputting video and audio is connected to the first electronic device 10, the HDMI of the second electronic device 20 is used. By connecting the connector 28 and the first HDMI connector 19 </ b> A of the first electronic device 10 by the HDMI cable 1, both video data and audio data can be transmitted to the second electronic device 20.

  However, in this case, the pixel clock transmitted from the HDMI source 11 to the HDMI sink 21 through the TMDS clock channel is based on the video master clock generated in the decoder 14 of the HDMI source 11 as a source. Therefore, in the second electronic device 20, an analog audio signal waveform is generated by the audio master clock generated based on the pixel clock including the jitter component due to the influence of the high frequency noise in the first electronic device 10. Is restored. In this case, the sound quality may be adversely affected by the jitter component included in the audio master clock.

  On the other hand, when the HDMI connector 28 of the second electronic device 20 and the second HDMI connector 19B of the first electronic device 10 are connected by the HDMI cable 1 as shown in FIG. 4, a decoder is connected to the second electronic device 20. Instead of the video data from 14, a differential signal corresponding to the image data of “black (0)” is transmitted. Therefore, significant video data cannot be reproduced by the second electronic device 20, but high-quality audio data can be obtained by the second electronic device 20 for the following reason.

  That is, the pixel clock transmitted from the HDMI source 11 to the HDMI sink 21 uses the oscillation frequency signal of the dedicated crystal oscillator 15 arranged in the vicinity of the second transmitter 13 as a source. Therefore, the transmission path length of the clock sourced from the oscillation frequency signal of the dedicated crystal oscillator 15 is shorter than the transmission path length of the clock sourced from the frequency signal oscillated from the crystal oscillator in the decoder 14. I'm sorry. Here, the transmission path length of the clock using the frequency signal oscillated from the crystal oscillator in the decoder 14 as the source is the transmission path length of the clock from the crystal oscillator in the decoder 14 to the first transmitter 12, a dedicated crystal. The clock transmission path length using the oscillation frequency signal of the oscillator 15 as a source is the clock transmission path length from the dedicated crystal oscillator 15 to the second transmitter 13. By shortening the transmission path length of the clock, the influence of the high frequency noise in the first electronic device 10 on the clock is reduced, and the amount of jitter generated in the pixel clock transmitted from the HDMI source 11 to the HDMI sink 21 Can be reduced. Therefore, the second electronic device 20 can obtain a high-quality sound corresponding to the audio data transmitted from the first electronic device 10 through the HDMI cable 1.

  As described above, in this embodiment, the sampling rate converter 17 sets the sampling rate of the baseband audio data supplied from the decoder 14 to the dedicated transmitter arranged in the vicinity of the second transmitter 13. It matches the rate of the audio master clock generated from the oscillation frequency signal of the crystal oscillator 15. Then, using the oscillation frequency signal of the dedicated crystal oscillator 15 as a source, the second transmitter 13 generates a pixel clock and transmits it to the receiver 22 of the HDMI sink 21. As a result, audio data can be transmitted from the HDMI source 11 to the HDMI sink 21 with high quality.

  In the above description, a device such as a television receiver capable of outputting video and audio is connected to the first electronic device 10 as the second electronic device 20, but only audio can be output. It is also possible to connect the device as the second electronic device 20 to the first electronic device 10.

  It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... HDMI cable 10 ... 1st electronic device 11 ... HDMI source 12 ... 1st transmitter 13 ... 2nd transmitter 14 ... Decoder 15 ... Crystal oscillator 16 ... Clock generation part 17 ... Sampling rate converter 18 ... Signal generation Unit 19A: First HDMI connector 19B: Second HDMI connector 20 ... Second electronic device 21 ... HDMI sink 22 ... Receiver 23 ... Video processing unit 24 ... Audio processing unit 25 ... Display unit 26 ... Audio clock reproduction unit 27 ... Audio output unit 28 ... HDMI connector 100 ... Data transmission system

Claims (5)

A first oscillator that oscillates a predetermined frequency signal; generates a first video master clock and a first audio master clock from the frequency signal of the first oscillator; The baseband video data is output by decoding the compression-coded video data using the master clock for decoding, and the compression-coded audio data is decoded using the first audio master clock. A decoding unit for outputting baseband audio data,
A first transmitter capable of transmitting the baseband video data and audio data and a pixel clock corresponding to the first video master clock to an externally connected device using a plurality of channels;
A second oscillator for oscillating a predetermined frequency signal;
An audio clock generator for generating a second audio master clock from the frequency signal of the second oscillator;
A conversion unit that converts a sampling frequency of the baseband audio data output from the decoding unit in accordance with the generated second audio master clock;
A signal generator for generating a second video master clock from the oscillation frequency of the second oscillator;
At least the audio data output from the conversion unit and converted from the sampling frequency, and a pixel clock corresponding to the master clock for the second video is externally connected using the plurality of channels. An electronic device comprising: a second transmission unit capable of transmitting to the electronic device. The electronic device according to claim 1,
The signal generator generates “0” video data synchronized with the master clock for the second video, instead of the baseband video data output from the decoder to the first transmitter. Supplying the second transmitter together with the master clock for the second video,
The second transmitter is synchronized with the second video master clock in addition to the audio data with the sampling frequency converted and a pixel clock corresponding to the second video master clock. An electronic device that can transmit “0” video data to externally connected devices. The electronic device according to claim 2,
The decoding unit
Further outputting a first bit clock and a first LR clock related to the baseband audio data;
The converting unit outputs the first bit clock and the first LR clock output from the decoding unit with the second bit clock and the first LR clock based on the generated second video master clock. 2 to LR clock,
The second transmission unit transmits the audio data output from the conversion unit to an externally connected device in accordance with a second bit clock and a second LR clock generated by the conversion unit. . The electronic device according to claim 3,
The second oscillator is an electronic device disposed in the vicinity of the second transmitter. A decoding unit generates a first video master clock and a first audio master clock from the frequency signal of the first oscillator, and is compressed and encoded using the first video master clock. The baseband video data is decoded and the baseband video data is output using the first audio master clock, and the compression-encoded audio data is decoded and the baseband audio data is output.
When an external device is connected to the first transmitter, the baseband video data and audio data and a pixel clock corresponding to the master clock for the first video using a plurality of channels To the equipment,
The audio clock generation unit generates a second audio master clock from the frequency signal of the second oscillator,
The conversion unit converts the sampling frequency of the baseband audio data output from the decoding unit according to the generated second audio master clock,
A signal generator generates a second video master clock from the oscillation frequency of the second oscillator;
When an external device is connected, the second transmission unit corresponds to at least the audio data output from the conversion unit and converted from the sampling frequency, and the master clock for the second video Transmitting the pixel clock to the device using the plurality of channels.

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