KR20120047383A

KR20120047383A - System and method of transmitting a signal of i2s between audio equipments

Info

Publication number: KR20120047383A
Application number: KR1020100108775A
Authority: KR
Inventors: 이관순
Original assignee: 지능일렉콤(주)
Priority date: 2010-11-03
Filing date: 2010-11-03
Publication date: 2012-05-14
Also published as: KR101210902B1

Abstract

The present invention relates to an I2S signal transmission system between audio devices, and more particularly, comprising: a digital data output semiconductor mounted in a first audio device to output I2S data; An I2S output amplifier configured to amplify the I2S data output from the digital data output semiconductor in the first audio device; An I2S connection cable for transmitting the I2S data amplified by the I2S output amplifier from the first audio device to a second audio device external to the first audio device; An I2S input amplifier for amplifying I2S data transmitted through the I2S connection cable in the second audio device; And a digital data input semiconductor mounted in the second audio device to receive I2S data amplified by the I2S input amplifier.

Description

System and method of transmitting a signal of I2 between audio equipments

The present invention relates to a signal transmission system between audio devices, and more particularly, to an I2S signal transmission system and method between audio devices for transmitting I2S data from an audio device to another audio device.

With the development of audio codec technology and digital signal processing technology, audio signals are also stored and transmitted as digital signals rather than analog signals. Accordingly, studies are being actively conducted to provide high quality voice services using digital signals.

Digital audio devices are divided into an external connection interface (Inter IC) and an internal IC (Inter IC Interface). Externally connected interfaces are the two standards that are currently used between devices.

SPDIF, a standard jointly proposed by Sony and PHILIPS, and AES / EBU, established by the Audio Engineering Society and European Broadcasting Union. The AES / EBU consists of a differential balance cable with a impedance of 110 ohms and a CANrON (XLR) terminal. These two interfaces are each connected through DIR (Digital Audio Interface Receiver) and DIT (Digital Audio Interface Transmitter), and when the original digital audio signal is decoded and transmitted to DIT, which is a transmitting IC, the receiving side is transmitted. The IC, DIR, encodes and re-uses the original digital audio. SPDIF is transmitted at a voltage level of 1V-pp, and AES / EBU is transmitted at a voltage level of 2V to 4V-pp.

Meanwhile, SPDIF and AES / EBU methods, which are two representative examples of the external connection interface method, are widely used as an interface between commercial and professional audio devices. The main advantage of the above method is that it is possible to transmit a relatively high speed long distance with low noise due to a simple connection and an internal driver circuit between the DIT and DIR.

However, the decoding and encoding process of the original digital audio signal through DIT and DIR conversion and the structure itself to generate the master clock (MasterCLK) with the internal RC PLL of the DIR reduce the purity of the signal. The poor accuracy of the internal RC PLL causes the accuracy of the master clock (MasterCLK). As a result, there is a serious problem that the possibility of occurrence of jitter or departure of frequency time due to the departure of the clock phase CLK phase increases.

On the other hand, a communication method according to I2S (or I ² S) (Inter IC Sound) protocol is used for an interface between internal audio ICs. I2S is a serial bus design for digital audio devices and technologies, including CD players, DSPs, and digital TV sound. In an I2S design, audio data is processed separately from a clock signal. Separating the data from the clock signal eliminates the need for jitter-preventing devices and the like because no errors related to the jitter-inducing time occur. The I2S bus consists of three serial bus lines: one for the time-division multiplexed data channel (Serial Data (SD)), one for the Word Select (WS), and one for the Serial Clock (SCK). do.

In addition, I2S Enhanced Interface (I2S Enhanced Interface), with improved performance in I2S, is a low-jitter interface developed in collaboration with other manufacturers in UltraAnalog. While the S / PDIF interface has been improved for development as a means of clock transfer, the performance has been improved from I2S to I2S enhanced interface. I2S was originally implemented as a 13W3 cable for transmitting component video and control signals. The cable is covered with three coaxial and five pairs of twisted wires, two of which transmit the master clock in balanced mode. The twisted wire carries the bit clock, word clock, channel state data and audio data. S / PDIF transmits audio data and clock together, but I2S is more advantageous for transmission because it transmits audio data and clock separately.

As such, the internal connection between the digital audio ICs is configured under the assumption that the signal lines have a relatively short length, unlike the external connection interface. Therefore, because the connection between internal ICs increases, the longer the signal line is, the more likely it is to be exposed to various electricity and magnetism and be affected by noise. In addition, unlike the external connection interface method, internal connection does not require driver circuits when connecting devices, and uses a signal of TTL or CMOS level. In addition, it is a connection between internal ICs, but the serial transmission method is used instead of parallel considering the signal speed and the number of transmission lines.

On the other hand, to deliver the original digital audio (RAW Digital Audio) signal internally at least the signals shown in Table 1 are required.

Name Description Signal name Serial Bit Data Digital audio data transmitted in serial. SD Serial LR Signal to distinguish between Left State and Right State LR Serial Bit CLK CLK for Digital Audio Data Sync BCLK Serial Master CLK Master click for full sync MCLK

As described above, the I2S standard is substantially a digital audio signal standard defined by PHILIPS, and there are other serial transmission standards having the same signal name. In Table 1, since 'Serial LR' is the same as the actual digital audio frequency, the sample frequency of the current signal can be known by knowing the period of 'Serial LR'. In addition, since the length of the bit data of the I2S bit length is up to 32 bits per left and right, the data of 64 bits (left and right) per word (word) of one sample is provided. Therefore, there are 64 bit clocks (Bit CLK) per sample. If the frequency of LR is known, the bit clock (Bit CLK) can be easily known. For example, with a sample frequency of 48KHz, the bit clock is (BCLK) 1 / ((1 / 48KHz) / 64) = 3.072MHz.

On the other hand, I2S is an internal IC connection standard, so it is a serial method, but it can be regarded as 'RAW Digital Audio Signal' for transmission between devices. Therefore, transmission between internal devices may assume that the data loss rate is 0%.

However, if I2S is used as an external connection interface rather than internally, the data loss rate is exposed to an environment larger than 0%. In other words, TTL or CMOS level signal is used for internal signal transmission, but if these signals go out, they are affected by transmission effect by electric and magnetic wave and LOND noise of GND.

In particular, BCLK with a signal rate of several MHz and MCLK with a signal rate of several tens of MHz become more vulnerable to noise. Therefore, if I2S is to be used as an external connection interface, there must be a design to keep the signal line short or to adopt a transmission method suitable for a high speed external connection interface.

As described above, the I2S interface is used for data transmission between the semiconductor chips (IC) in the audio device as described above, and when the I2S signal is output to the outside of the device to communicate between the audio devices, noise and data loss generated during input / output Because of this, it is impossible to transmit I2S signals directly.

1 is a block diagram showing a data transmission system between audio devices according to the prior art. Referring to FIG. 1, in order to receive the I2S signal output from the digital data output semiconductor 101 of the first audio device 100 from the digital data input semiconductor 114 of the second audio device 110, each cable that can be transmitted is transmitted. You need to convert them according to the type of.

That is, when the data is to be transmitted by connecting the optical cable 121 between the two audio devices, the I2S signal output from the digital data output semiconductor 101 is optically transmitted by the first A digital conversion circuit 102. After converting to an optical signal, the optical cable 121 transmits the signal to the second audio device 110. In the second audio device 110, the optical signal received by the optical cable 121 is converted into an I2S signal by the first B digital conversion circuit 111, and then the I2S signal is transmitted to the digital data input semiconductor 114. Will be entered.

In addition, in the case where the audio data is to be transmitted by connecting a coaxial cable 122 between the two audio devices, the I2S signal output from the digital data output semiconductor 101 is coaxially formed by the second A digital conversion circuit 103. After converting into a coaxial signal, the coaxial cable 122 transmits the signal to the second audio device 110. In the second audio device 110, the coaxial cable signal received by the coaxial cable 122 is converted into an I2S signal by the second B digital conversion circuit 112, and then the I2S signal is input to the digital data input semiconductor 114. Will be entered.

Similarly, when the data is to be transmitted by connecting to the other cable 123, the 3A digital conversion circuit 104 converts the transmission signal suitable for the cable and transmits the data, and then the 3B digital conversion circuit 113 again. By returning to the I2S signal to input the signal.

Meanwhile, if a signal is converted and transmitted through a digital conversion circuit such as an optical signal or a coaxial cable signal instead of the I2S signal transmission between audio devices, a loss of sound quality occurs during the conversion process, and conversion to another digital communication. Since a separate circuit conversion circuit is required, the manufacturing cost is high.

Therefore, there is a need for a method capable of transmitting an I2S audio signal at a long distance without data loss and noise.

An object of the present invention is to provide an I2S signal transmission system and method between audio devices capable of communicating high quality data to the outside without loss of data when transmitting I2S data between audio devices.

It is also an object of the present invention to provide an I2S signal transmission system and method between audio devices capable of communicating high quality data to the outside without noise generated when input and output to the outside when transmitting I2S data between audio devices.

It is also an object of the present invention to provide an I2S signal transmission system and method between audio devices capable of communicating high quality data to the outside without a separate digital communication conversion circuit when transmitting I2S data between audio devices.

In order to achieve the above object, an I2S signal transmission system between audio devices according to the present invention comprises: a digital data output semiconductor mounted in a first audio device for outputting I2S data; An I2S output amplifier configured to amplify the I2S data output from the digital data output semiconductor in the first audio device; An I2S connection cable for transmitting the I2S data amplified by the I2S output amplifier from the first audio device to a second audio device external to the first audio device; An I2S input amplifier for amplifying I2S data transmitted through the I2S connection cable in the second audio device; And a digital data input semiconductor mounted in the second audio device to receive I2S data amplified by the I2S input amplifier.

The I2S output amplifier may include a first resistor connected in series between at least one pin of the digital data output semiconductor and the I2S connection cable.

In addition, the I2S connection cable is characterized by using a cable of the LVDS transmission method, characterized in that the cable for HDMI communication.

The I2S input amplifier may include a second resistor connected in series between the I2S connection cable and at least one pin of the digital data input semiconductor.

The I2S input amplifier may further include a third resistor connected in parallel between the digital data plus input signal and the digital data minus input signal passed through the second resistor connected to one pin of the digital data input semiconductor. It features.

In addition, the digital data output semiconductor is characterized in that the pin configuration is a semiconductor to which the 'Flow-Through Design' is applied.

In order to achieve the above object, an I2S signal transmission method between audio devices according to the present invention comprises the steps of: outputting I2S data from a digital data output semiconductor mounted in a first audio device; Amplifying the I2S output data output from the digital data output semiconductor in the first audio device; Transmitting the amplified I2S data from the first audio device to a second audio device external to the first audio device through an I2S connection cable; Amplifying I2S input data transmitted via the I2S connection cable in the second audio device; And receiving the amplified I2S data from the digital data input semiconductor mounted in the second audio device.

In this case, the amplifying the I2S output data may be amplified by a first resistor connected in series between at least one pin of the digital data output semiconductor and the I2S connection cable.

In addition, the I2S connection cable is characterized in that the cable for HDMI communication.

The amplifying the I2S input data may be amplified by a second resistor connected in series between the I2S connection cable and at least one pin of the digital data input semiconductor.

The amplifying of the I2S input data may be performed by a third resistor connected in parallel between the digital data plus input signal and the digital data minus input signal passing through the second resistor connected to one pin of the digital data input semiconductor. It is characterized by amplifying.

According to the present invention, the I2S digital data used only in the conventional audio device can be inputted and outputted to the outside, thereby enabling high quality music to be reproduced due to jitter reduction of the data.

In addition, according to the present invention, when the I2S data is transmitted between audio devices, high-quality data is communicated to the outside without a separate digital communication conversion circuit, thereby reducing the manufacturing cost of the conversion device, and reducing data loss occurring during the conversion process. There is an advantage that can be reduced.

In addition, according to the present invention there is an advantage that can be communicated between the audio device without noise and data loss caused when input and output the I2S data communication data between the semiconductor to the outside of the device.

1 is a block diagram showing a data transmission system between audio devices according to the prior art.
2 is a block diagram showing a data transmission system between audio devices according to the present invention;
3 is a circuit diagram showing an I2S output amplifier in a transmitting audio device according to an embodiment of the present invention.
4 is a circuit diagram showing an I2S output amplifier in a transmitting audio device according to an embodiment of the present invention.

In the present invention, when I2S data is to be transmitted from an audio device to another audio device, I2S data can be transmitted without data loss and noise, instead of transmitting I2S data after digital data conversion processing according to a cable signal. We propose a signal transmission system and method.

To this end, an I2S output amplifier is additionally installed at the semiconductor output terminal of the transmitting audio device, the I2S data is transmitted without loss through the I2S connection cable, and an I2S input amplifier is additionally installed at the semiconductor input terminal of the receiving audio device.

In this way, high-quality music data can be transmitted to an external device due to jitter reduction, and the manufacturing cost required for the conversion device can be saved because there is no need for a circuit for converting to another digital communication.

On the other hand, when the external connection interface of the I2S is a short signal line, the most important point is the impedance and capacitance of the circuit line. These two requirements are important factors in determining the transmission status of signal lines, so care must be taken when connecting directly. If the capacitance is large on the signal line, the signals having the characteristics of the square wave have fluctuations in the slope of the signal, so that the time for determining H and L in the devices that determine the threshold due to the voltage difference Bring it. Here, the bit data is synchronized with the bit clock Bit CLK, so if the threshold of the bit clock Bit CLK changes due to the slope change of the bit clock Bit CLK, the worst If there is a loss of data, it can lead to significant time fluctuations in the music. The same is true for the 'Serial LR' signal.

In addition, if the MCLK, which is the fastest and the main sync frequency of the Digital Audio IC, changes the time due to these external factors, more time difference and data loss is expected. Therefore, it is concluded that I2S transmission using short signal lines is not environmentally safe.

As described above, using an internal signal for external connection has many difficulties. Therefore, in order to use I2S for external connection without loss, it is necessary to use a signal specification for a high speed external connection interface according to an embodiment of the present invention.

Most of the signal specifications for high speed externally connected interfaces that have been proven and used for industrial use are based on 'Differential Transmission'. The method is a method of swinging a signal with + and-to be strong in external noise, and has many advantages in transmitting and restoring a signal. Typical 'Differential Transmission' methods are XLR Balance method of Analog Audio, AES / EBS method of Digital Audio, USB BUS, SATA BUS of PC, etc., and can transmit a large amount of signals at high speed. .

On the other hand, the LVDS (Low Voltage Differential Signaling) method is mostly used to transmit digital signals. The above-described USB and SATA and DVI and HDMI, which are digital video transmission methods, are also LVDS. Therefore, in order to connect I2S between devices by external connection, LVDS method should be used to safely transmit the transmission signal from the influence of external noise.

DETAILED DESCRIPTION Hereinafter, a detailed description of a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

2 is a block diagram showing a data transmission system between audio devices according to the present invention. Referring to FIG. 2, when the I2S data is to be transmitted from the first audio device 200 to the second audio device 210 according to the present invention, the digital data output semiconductor of the first audio device 200 (ie, The integrated circuit (IC) 201 transmits the I2S data to the digital data input semiconductor 212 of the second audio device 210 through the I2S connection cable directly without digital data conversion processing. In this case, since the I2S data is a signal for direct communication between the semiconductor chips, attenuation of the signal may appear when connecting to an external device through a cable. Therefore, in order to solve this problem, the digital data output semiconductor 201 of the first audio device 200 on the output side is further provided with an I2S output amplifier 202, and the digital data input semiconductor of the second audio device 210 on the input side ( 212 is further provided with an I2S input amplifier 211.

The detailed configuration of the I2S output amplifier 202 and the I2S input amplifier 211 may be implemented using any amplifier circuit, and amplifies I2S data for transmitting an audio signal by dividing a data signal and a clock signal. Any circuit that can be applied is applicable. For example, the signal can be amplified by adding elements such as resistors, capacitors, and diodes to terminals output from the pins of the I2S signal output from the semiconductor chip, and various other signal amplification elements can be used. Examples of detailed configurations of the I2S output amplifier 202 and the I2S input amplifier 211 will be described later with reference to FIGS. 3 and 4.

As such, the I2S signal output from the digital data output semiconductor 201 may be transmitted to the digital data input semiconductor 212 without loss due to data conversion, and jitter generation may be performed by using the I2S signal as audio signal transmission data as it is. This prevents high quality music from being played back.

An I2S connection cable for transmitting I2S data is used between the first audio device 200 and the second audio device 210. In this case, the I2S connection cable 220 may use any cable capable of communicating between an output pin of the digital data output semiconductor 201 and an input pin of the digital data input semiconductor 212. For example, it is also possible to use a cable of high definition multimedia interface (HDMI) standard. In addition, various cables for the conventional digital data communication may be reused, and a dedicated I2S communication cable made exclusively for I2S communication may be used.

3 and 4, a circuit configuration example of the I2S output amplifier 202 and the I2S input amplifier 211 according to an embodiment of the present invention will be described.

3 is a circuit diagram illustrating an I2S output amplifier of a transmitting audio device according to an exemplary embodiment of the present invention. Referring to FIG. 3, the I2S signal may be implemented as a 13W3 signal for transmitting component video and control signals. In this case, two signals transmit a master clock in a balanced mode, and ten signals transmit a bit clock, a word clock, channel state data, and audio data. In this case, the resistors R1 to R10 may be connected in series to a signal output from each pin of the semiconductor chip according to the exemplary embodiment of the present invention. For example, a 22Ω R5 resistor may be connected in series to a DP1 (Data Plus) output pin, and a 22Ω R6 resistor may be connected in series to a DM1 (Data Minus) output pin. As described above, by adding a resistor to the output pin, the added resistor generates a voltage difference between the output of the semiconductor pin and the data to be transmitted through the cable, thereby amplifying the signal output from the semiconductor pin. By adding resistors R9 and R10 to the output pins of the clock signal TX SCL and the data signal TX SDA of the transmission data in the same manner, the transmitted signal can be amplified. In addition, impedance matching and noise cancellation may be performed through the series resistors. On the other hand, in order to amplify the signal output from each pin equally, it is preferable to add a resistor of the same resistance value to each pin.

4 is a circuit diagram illustrating an I2S output amplifier of a transmitting audio device according to an exemplary embodiment of the present invention. Referring to FIG. 4, resistors R21 to R37 may be connected in series and in parallel to a signal transmitted through an I2S cable and input to each pin of a semiconductor chip according to an exemplary embodiment of the present invention. For example, a 22 Ω R29 resistor may be connected in series to a DP1 (Data Plus) input pin, and a 22 Ω R30 resistor may be connected in series to a DM1 (Data Minus) input pin. As described above, by adding a resistor at the front end of the input pin, the added resistance causes a voltage difference between the input of the semiconductor pin and the data signal transmitted through the cable to amplify the signal input to the semiconductor pin. Similarly, resistors R33 and R34 are also added to the front end of the input signal of the clock signal TX SCL and the data signal TX SDA of the transmission data, thereby enabling amplification of the transmitted signal.

Meanwhile, a resistor may be further connected in parallel between a DP signal and a DM signal connected to one pin of the input semiconductor and passed through each resistor connected in series. For example, an R23 resistor of 100Ω may be connected between the DP1 and DP2 input signals, and a 100Ω resistor may also be connected between DP2 and DM2, DP3 and DP3, DP4, and DP4. In addition, an R35 series resistor of 1KΩ may be connected to the DET_I2S input terminal, and an R37 pull down resistor of 4.7KΩ may be additionally connected.

As such, by adding an amplifying unit to the output terminal and the input terminal of the digital data output semiconductor chip, the I2S data communication can be communicated not only between the chips in the device but also between external devices. As a result, the I2S data can be transmitted over a long distance without data loss and noise, thereby making it possible to reproduce high quality music. In addition, since the digital data conversion circuit according to the cable standard does not need to be added separately, the production cost of the audio device can be reduced.

I2S has synchronous and asynchronous method for internal connection and external connection. The difference between the two methods is whether the master clock (MCLK) is used for the connection interface among the four signals, and depending on the system, synchronous or asynchronous may be selected. Synchronous, asynchronous, or required signals have a difference in MCLK, so synchronous support is not a big problem because asynchronous support does not require MCLK. This concludes that at least four signal transmissions are required. Similarly, LVDS transmission requires four ports, and requires a transport connector standard or a transmission IC that supports four ports. Therefore, it is desirable to use an IC that supports 4 port LVDS transmission.

Meanwhile, as an additional consideration, a transport connector standard supporting 4 ports is required. As a method of implementing this, a method of manufacturing a connector by setting a new standard or using a commercial connector system is possible. The use of commercial connectors has the advantage of reducing manufacturing and system construction costs

At this time, there is an HDMI connection method as an example of a connector satisfying two conditions such as LVDS 4 port support and a commercial connector system. HDMI is a standard for video transmission including audio, and there is a transmission line that supports 4 ports of twisted pair structure supporting 'Differential Transmission' inside. Do. And since the basic transmission performance supports speeds that are several times the I2S transmission specification, performance is not a problem at all. In other words, to use I2S for an external connection interface, it is preferable to use a connector system of HDMI standard.

The HDMI is a transmission system with international standards. International standards exist for connectors and cables, and because of the use of LVDS, there are design rules for internal circuits. This is a rule that must be observed in systems that use LVDS as a transmission standard or 'Differential Transmission' as a transmission standard. For example, the same design rules apply to USB, SATA, and IEEE1394.

Of course, I2S standard having a transmission frequency specification of 40MHz or less is transmitted using an ultra-fast HDMI transmission system, so there are many margins, but if you use LVDS method, a rule that must be followed is a Differential Pair Design Rule. The 'Differential Pair Design Rule' is a part that is commonly applied to various transmission methods adopting the 'Differential Transmission' method as well as the LVDS standard. Of course, each method has a different margin in terms of transmission speed and characteristics, but the common aspect is matching of 'Differential Pair Line'.

On the other hand, the most demanding 'Signal Pair Matching' method is SATA and HDMI with high transmission frequencies and strict 'Pair Matching' of 'Differential Line'. The connectors and cables are already in compliance with the specification, so this is not a problem, but the designer's primary concern is the connection between the connector and the driver IC.

As described above, since I2S has a transmission frequency of 40 MHz or less, a large problem may not occur. However, products always have problems when the operating environment is poor, so it is desirable to design them according to prescribed design rules.

It is also basic to select ICs that meet LVDS specifications for IC selection, but it is recommended to select a product with a 'Flow-Through Design' with a pin configuration. 'Flow-Through' refers to a design that has a pin map for the signal flow. In other words, the input is designed to be on the left side only in order, and the output is on the right side only in order, minimizing the 'via' of signal line during PCB design and preventing the wiring from being twisted as much as possible.

In summary, as described above, the I2S audio signal may be referred to as an original digital audio signal and used for internal IC connection. However, there are various vulnerabilities to use as an external connection interface. Therefore, according to an embodiment of the present invention, the transmission can be minimized by using the LVDS scheme, and the commercially available HDMI system has the advantage that the signal specifications can be matched and can be configured at low cost. At this time, to use I2S audio signal as an external connection interface using HDMI, design by 'Signal Pair Matching', 'Differential Pair Design Rule', and use IC with 'Flow-Through Design' applied. It is desirable to.

On the other hand, in the embodiment of the present invention has been described with respect to specific embodiments, various modifications are possible without departing from the scope of the invention. Therefore, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

100, 200: first audio device 101, 201: digital data output semiconductor
102, 103, 104, 111, 112, 113: digital conversion circuit
110, 210: second audio device 114, 212: digital data input semiconductor
121: OPT cable 122: COAX cable
123: other cable 202: I2S output amplifier
211: I2S input amplifier 220: I2S connection cable

Claims

A digital data output semiconductor mounted in the first audio device and outputting I2S data;
An I2S output amplifier configured to amplify the I2S data output from the digital data output semiconductor in the first audio device;
An I2S connection cable for transmitting the I2S data amplified by the I2S output amplifier from the first audio device to a second audio device external to the first audio device;
An I2S input amplifier for amplifying I2S data transmitted through the I2S connection cable in the second audio device; And
And a digital data input semiconductor mounted in the second audio device and receiving I2S data amplified by the I2S input amplifying unit.

The method of claim 1, wherein the I2S output amplifier,
And a first resistor connected in series between at least one pin of the digital data output semiconductor and the I2S connection cable.

The method of claim 1, wherein the I2S connection cable,
I2S signal transmission system between audio devices, characterized by using a cable of the LVDS transmission method.

The method of claim 3, wherein the I2S connecting cable,
I2S signal transmission system between audio equipment, characterized in that the cable for HDMI communication.

The method of claim 1, wherein the I2S input amplification unit,
And a second resistor connected in series between the I2S connection cable and at least one pin of the digital data input semiconductor.

The method of claim 5, wherein the I2S input amplification unit,
And a third resistor connected in parallel between the digital data plus input signal and the digital data minus input signal passed through the second resistor respectively connected to one pin of the digital data input semiconductor. Signal transmission system.

The method of claim 1, wherein the digital data output semiconductor,
I2S signal transmission system between audio devices, characterized in that the pin configuration is a semiconductor with 'Flow-Through Design' applied.

Outputting I2S data from a digital data output semiconductor mounted in the first audio device;
Amplifying the I2S output data output from the digital data output semiconductor in the first audio device;
Transmitting the amplified I2S data from the first audio device to a second audio device external to the first audio device through an I2S connection cable;
Amplifying I2S input data transmitted via the I2S connection cable in the second audio device; And
And receiving the amplified I2S data from the digital data input semiconductor mounted in the second audio device.

The method of claim 8, wherein the amplifying the I2S output data comprises:
And amplifying by a first resistor connected in series between at least one pin of the digital data output semiconductor and the I2S connection cable.

The method of claim 8, wherein the I2S connecting cable,
I2S signal transmission method between audio devices, characterized by using a cable of the LVDS transmission method.

The method of claim 10, wherein the I2S connecting cable,
I2S signal transmission method between audio devices, characterized in that the cable for HDMI communication.

The method of claim 8, wherein the amplifying the I2S input data comprises:
And amplifying by a second resistor connected in series between the I2S connection cable and at least one pin of the digital data input semiconductor.

The method of claim 12, wherein the amplifying the I2S input data comprises:
I2S signals between audio devices characterized in that they are amplified by a third resistor connected in parallel between the digital data plus input signal and the digital data minus input signal passed through the second resistor respectively connected to one pin of the digital data input semiconductor. Transmission method.

The method of claim 8, wherein the digital data output semiconductor,
I2S signal transmission method between audio devices, characterized in that the pin configuration is a semiconductor to which the 'Flow-Through Design' is applied.