Patent Description:
More specifically, the present disclosure relates to a signal receiving apparatus including at least one equalizer and a signal processing method thereof.

A high definition multimedia interface (HDMI) is one of an uncompressed digital video/audio interface standards. The HDMI transmits high-definition multimedia information as high-frequency signal, which may cause problems such as noise or signal leakage. In particular, as HDMI <NUM> (or higher) is supported, the frequency increases. In addition, as signal transmission through a longer cable is expected, signal attenuation is expected to be more severe. Therefore, the role of an equalizer of a signal receiving apparatus is becoming more important.

<CIT> discloses an integrated circuit with continuously adaptive equalization circuitry. <CIT> teaches an equalizer circuit and its control method. <CIT> relates to a method of adapting a receiver for equalization of an input data signal using a variable gain amplifier loop.

An object of the present disclosure devised to solve the problem lies in a signal receiving apparatus capable of improving signal compensation performance of an equalizer, and a signal processing method thereof.

An object of the present disclosure devised to solve the problem lies in a signal receiving apparatus for implementing automatic gain control (AGC) in an equalizer, and a signal processing method thereof.

These objects are provided by independent claims <NUM> and <NUM>.

The signal receiving apparatus further comprises a processor configured to adjust the swing level of the output signal.

The signal receiving apparatus further comprises a detector configured to detect the swing level of the output signal, wherein the processor is configured to adjust the swing level of the output signal such that the swing level of the output signal falls within the preset range based on a result of detection of the detector.

The processor is configured to determine DC gain of the first equalizer for enabling the swing level of the output signal to fall within the preset range.

The processor is configured to determine the DC gain by stepwise changing the DC gain until the swing level of the output signal falls within the preset range.

When the DC gain is determined, the processor is configured to determine AC gain by detecting an error rate of the output signal with respect to the determined DC gain.

The equalizer compensates for the signal received through the terminal according to the determined DC gain and the AC gain.

The first equalizer is a continuous time linear equalizer (CTLE), and the second equalizer is a decision feedback equalizer (DFE).

The signal processing method further comprises adjusting the swing level of the output signal such that the swing level of the output signal falls within the preset range.

The signal processing method further comprises determining DC gain of the first equalizer for enabling the swing level of the output signal to fall within the preset range.

The determining of the DC gain comprises determining the DC gain by stepwise changing the DC gain until the swing level of the output signal falls within the preset range.

The signal processing method further comprises when the DC gain is determined, determining AC gain by detecting an error rate of the output signal with respect to the determined DC gain.

According to the present disclosure, since operation stability of an equalizer is secured and performance is improved, inter-symbol interference is further reduced.

According to the present disclosure, since adaptive equalizer gain adjustment is possible with respect to an input signal, it is possible to maximize compensation efficiency of signals received through various cables and various signal transmitting apparatuses.

The suffixes "module" and "unit" for components used in the description below are assigned or mixed in consideration of easiness in writing the specification and do not have distinctive meanings or roles by themselves.

<FIG> is a schematic view showing a state in which a signal receiving apparatus according to an embodiment of the present disclosure receives a signal through a high definition multimedia interface (HDMI).

As shown in <FIG>, the signal receiving apparatus <NUM> may be connected to an external device <NUM> through an interface <NUM> to receive a video/audio/control signal from the external device <NUM>.

Here, the interface <NUM> may be a high definition multimedia interface (HDMI), but this is merely an example and is not limited thereto. In the present disclosure, for convenience of description, it is assumed that the interface <NUM> is an HDMI.

The signal receiving apparatus <NUM> includes a terminal 10a connected with the HDMI <NUM>, and the terminal 10a may receive the signal of the external device <NUM> through the HDMI <NUM>. The terminal 10a may be an HDMI terminal. Similarly, the external device <NUM> may include a terminal 20a connected with the HDMI <NUM>, and the terminal 20a may transmit a signal to the HDMI <NUM>.

The HDMI <NUM> may include a pair of connectors 1a and 1b and an HDMI cable 1c located between the pair of connectors 1a and 1b. The HDMI cable 1c may include signal lines for signal transmission between the pair of connectors 1a and 1b, and the connectors 1a and 1b may be terminals for connection to a sink apparatus or a source apparatus.

The signal receiving apparatus <NUM> may be a sink apparatus, and the sink apparatus may include all types of apparatuses capable of receiving and reproducing signals (e.g., HDMI signals) from a source apparatus. For example, the sink apparatus may be implemented as various apparatuses such as a TV, a computer, a DVD player, a cellular phone, a smartphone, a personal digital assistant (PDA), a laptop PC, a tablet PC, an electronic book, an electronic picture frame, a kiosk, etc..

The external device <NUM> may be a source apparatus and includes all types of apparatus capable of generating and transmitting signals (e.g., HDMI signals). For example, the external device <NUM> may be implemented as various apparatuses such as a TV, a computer, a DVD player, a cellular phone, a smartphone, a personal digital assistant (PDA), a laptop PC, a tablet PC, an electronic book, an electronic picture frame, a kiosk, a Blu-ray disc, a set-top box, etc..

<FIG> is a block diagram showing the configuration of the signal receiving apparatus of <FIG>.

The signal receiving apparatus <NUM> may be a display apparatus <NUM> described below or a component configuring the display apparatus <NUM>. In the present disclosure, it is assumed that the signal receiving apparatus <NUM> is the display apparatus <NUM> described below.

Meanwhile, the signal receiving apparatus <NUM> may include some or all of the components shown in <FIG>. That is, <FIG> shows only an example of describing the configuration of the signal receiving apparatus <NUM>, and the configuration of the signal receiving apparatus <NUM> may be various.

Referring to <FIG>, a display device <NUM> can include a broadcast receiver <NUM>, an external device interface <NUM>, a storage <NUM>, a user input interface <NUM>, a controller <NUM>, a wireless communication interface <NUM>, a display <NUM>, an audio output interface <NUM>, and a power supply <NUM>.

The broadcast receiver <NUM> can include a tuner <NUM>, a demodulator <NUM>, and a network interface <NUM>.

The tuner <NUM> can select a specific broadcast channel according to a channel selection command. The tuner <NUM> can receive broadcast signals for the selected specific broadcast channel.

The demodulator <NUM> can divide the received broadcast signals into video signals, audio signals, and broadcast program related data signals and restore the divided video signals, audio signals, and data signals to an output available form.

The network interface <NUM> can provide an interface for connecting the display device <NUM> to a wired/wireless network including internet network. The network interface <NUM> can transmit or receive data to or from another user or another electronic device through an accessed network or another network linked to the accessed network.

The network interface <NUM> can access a predetermined webpage through an accessed network or another network linked to the accessed network. That is, it can transmit or receive data to or from a corresponding server by accessing a predetermined webpage through network.

Then, the network interface <NUM> can receive contents or data provided from a content provider or a network operator. That is, the network interface <NUM> can receive contents such as movies, advertisements, games, VODs, and broadcast signals, which are provided from a content provider or a network provider, through network and information relating thereto.

Additionally, the network interface <NUM> can receive firmware update information and update files provided from a network operator and transmit data to an internet or content provider or a network operator.

The network interface <NUM> can select and receive a desired application among applications open to the air, through network.

The external device interface <NUM> can receive an application or an application list in an adjacent external device and deliver it to the controller <NUM> or the storage <NUM>.

The external device interface <NUM> can provide a connection path between the display device <NUM> and an external device. The external device interface <NUM> can receive at least one of image and audio outputted from an external device that is wirelessly or wiredly connected to the display device <NUM> and deliver it to the controller. The external device interface <NUM> can include a plurality of external input terminals. The plurality of external input terminals can include an RGB terminal, at least one High Definition Multimedia Interface (HDMI) terminal, and a component terminal.

An image signal of an external device inputted through the external device interface <NUM> can be outputted through the display <NUM>. A sound signal of an external device inputted through the external device interface <NUM> can be outputted through the audio output interface <NUM>.

An external device connectable to the external device interface <NUM> can be one of a set-top box, a Blu-ray player, a DVD player, a game console, a sound bar, a smartphone, a PC, a USB Memory, and a home theater system but this is just exemplary.

Additionally, some content data stored in the display device <NUM> can be transmitted to a user or an electronic device, which is selected from other users or other electronic devices pre-registered in the display device <NUM>.

The storage <NUM> can store signal-processed image, voice, or data signals stored by a program in order for each signal processing and control in the controller <NUM>.

Additionally, the storage <NUM> can perform a function for temporarily store image, voice, or data signals outputted from the external device interface <NUM> or the network interface <NUM> and can store information on a predetermined image through a channel memory function.

The storage <NUM> can store an application or an application list inputted from the external device interface <NUM> or the network interface <NUM>.

The display device <NUM> can play content files (for example, video files, still image files, music files, document files, application files, and so on) stored in the storage <NUM> and provide them to a user.

The user input interface <NUM> can deliver signals inputted from a user to the controller <NUM> or deliver signals from the controller <NUM> to a user. For example, the user input interface <NUM> can receive or process control signals such as power on/off, channel selection, and screen setting from the remote controller <NUM> or transmit control signals from the controller <NUM> to the remote controller <NUM> according to various communication methods such as Bluetooth, Ultra Wideband (WB), ZigBee, Radio Frequency (RF), and IR.

Additionally, the user input interface <NUM> can deliver, to the controller <NUM>, control signals inputted from local keys (not shown) such as a power key, a channel key, a volume key, and a setting key.

Image signals that are image-processed in the controller <NUM> can be inputted to the display <NUM> and displayed as an image corresponding to corresponding image signals. Additionally, image signals that are image-processed in the controller <NUM> can be inputted to an external output device through the external device interface <NUM>.

Voice signals processed in the controller <NUM> can be outputted to the audio output interface <NUM>. Additionally, voice signals processed in the controller <NUM> can be inputted to an external output device through the external device interface <NUM>.

Besides that, the controller <NUM> can control overall operations in the display device <NUM>.

Additionally, the controller <NUM> can control the display device <NUM> by a user command or internal program inputted through the user input interface <NUM> and download a desired application or application list into the display device <NUM> in access to network.

The controller <NUM> can output channel information selected by a user together with processed image or voice signals through the display <NUM> or the audio output interface <NUM>.

Additionally, according to an external device image playback command received through the user input interface <NUM>, the controller <NUM> can output image signals or voice signals of an external device such as a camera or a camcorder, which are inputted through the external device interface <NUM>, through the display <NUM> or the audio output interface <NUM>.

Moreover, the controller <NUM> can control the display <NUM> to display images and control broadcast images inputted through the tuner <NUM>, external input images inputted through the external device interface <NUM>, images inputted through the network interface, or images stored in the storage <NUM> to be displayed on the display <NUM>. In this case, an image displayed on the display <NUM> can be a still image or video and also can be a 2D image or a 3D image.

Additionally, the controller <NUM> can play content stored in the display device <NUM>, received broadcast content, and external input content inputted from the outside, and the content can be in various formats such as broadcast images, external input images, audio files, still images, accessed web screens, and document files.

Moreover, the wireless communication interface <NUM> can perform a wired or wireless communication with an external electronic device. The wireless communication interface <NUM> can perform short-range communication with an external device. For this, the wireless communication interface <NUM> can support short-range communication by using at least one of Bluetooth™, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, Near Field Communication (NFC), Wireless-Fidelity (Wi-Fi), Wi-Fi Direct, and Wireless Universal Serial Bus (USB) technologies. The wireless communication interface <NUM> can support wireless communication between the display device <NUM> and a wireless communication system, between the display device <NUM> and another display device <NUM>, or between networks including the display device <NUM> and another display device <NUM> (or an external server) through wireless area networks. The wireless area networks can be wireless personal area networks.

Herein, the other display device <NUM> can be a mobile terminal such as a wearable device (for example, a smart watch, a smart glass, and a head mounted display (HMD)) or a smartphone, which is capable of exchanging data (or inter-working) with the display device <NUM>. The wireless communication interface <NUM> can detect (or recognize) a communicable wearable device around the display device <NUM>. Furthermore, if the detected wearable device is a device authenticated to communicate with the display device <NUM>, the controller <NUM> can transmit at least part of data processed in the display device <NUM> to the wearable device through the wireless communication interface <NUM>. Accordingly, a user of the wearable device can use the data processed in the display device <NUM> through the wearable device.

The display <NUM> can convert image signals, data signals, or OSD signals, which are processed in the controller <NUM>, or images signals or data signals, which are received in the external device interface <NUM>, into R, G, and B signals to generate driving signals.

Furthermore, the display device <NUM> shown in <FIG> is just one embodiment of the present invention and thus, some of the components shown can be integrated, added, or omitted according to the specification of the actually implemented display device <NUM>.

That is, if necessary, two or more components can be integrated into one component or one component can be divided into two or more components and configured. Additionally, a function performed by each block is to describe an embodiment of the present invention and its specific operation or device does not limit the scope of the present invention.

According to another embodiment of the present invention, unlike <FIG>, the display device <NUM> can receive images through the network interface <NUM> or the external device interface <NUM> and play them without including the tuner <NUM> and the demodulator <NUM>.

For example, the display device <NUM> can be divided into an image processing device such as a set-top box for receiving broadcast signals or contents according to various network services and a content playback device for playing contents inputted from the image processing device.

In this case, an operating method of a display device according to an embodiment of the present invention described below can be performed by one of the display device described with reference to <FIG>, an image processing device such as the separated set-top box, and a content playback device including the display <NUM> and the audio output interface <NUM>.

The audio output interface <NUM> receives the audio processed signal from the controller <NUM> and outputs the sound.

The power supply <NUM> supplies the corresponding power throughout the display device <NUM>. In particular, the power supply <NUM> supplies power to the controller <NUM> that can be implemented in the form of a System On Chip (SOC), a display <NUM> for displaying an image, and the audio output interface <NUM> for outputting audio or the like.

Specifically, the power supply <NUM> may include a converter for converting an AC power source into a DC power source, and a dc / dc converter for converting a level of the DC source power.

The remote controller <NUM> transmits a user input to the user input interface <NUM>. To this end, the remote controller <NUM> may use Bluetooth, radio frequency (RF) communication, infrared (IR) communication, ultra wideband (UWB), ZigBee, or the like. In addition, the remote controller <NUM> may receive video, audio, or data signal output from the user input interface <NUM> and display the video, audio, or data signal or output sound.

<FIG> is a view showing the physical layer of the external device interface shown in <FIG>.

The external device interface <NUM> of the signal receiving apparatus <NUM> may be an HDMI interface, but this is merely an example and is not limited thereto. In the present disclosure, it is assumed that the external device interface <NUM> is an HDMI interface, but this is only for convenience of description.

The physical layer of the HDMI interface may include at least one equalizer. Here, the equalizer may reinforce or cut the received signal, thereby reducing a jitter phenomenon wherein some aspects of a wave are deviated or displaced at a high frequency.

As shown in <FIG>, the HDMI interface includes a first equalizer and a second equalizer. The first equalizer may be a signal amplification linear equalizer and the second equalizer may be a non-linear equalizer for eliminating non-amplification bit interference (inter-symbol interference (ISI)). For example, the first equalizer may be a continuous time linear equalizer (CTLE) and the second equalizer may be a decision feedback equalizer (DFE), but this is only an example and is not limited thereto.

The CTLE may amplify a signal to adjust all frequency components of an input signal to a similar magnitude, thereby improving eye diagram performance.

The DFE may be a circuit for improving BER performance by eliminating inter-symbol interference of an input signal using a feedback filter. The DFE may compensate for a signal without amplifying a noise level.

When an HDMI is connected to an HDMI terminal, the CTLE may receive the signal of the external device through the HDMI terminal. That is, the CTLE may receive the signal of the external device received by the HDMI terminal, process the signal input through the HDMI terminal according to equalizer gain, and output the processed signal to the DFE.

The DFE may reduce inter-symbol interference by compensating for a signal through a subtraction operation between a signal output from the CTLE and a DFE variable (β, ISI term). At this time, the DFE variable is a feedback signal determined by an internal operation logic and is affected by a signal input to the DFE, that is, a signal output from the CTLE. That is, the signal output from the CTLE to the DFE may determine the DFE variable and affect the DFE logic. Accordingly, when the magnitude of the signal output from the CTLE to the DFE is out of the allowable voltage range of a digital-to-analog converter (DAC) in the DFE, the DFE variable may not be properly calculated and thus signal compensation may not be optimally performed. Accordingly, the magnitude of the signal output from the CTLE to the DFE shall be smaller than the allowable voltage range of the DAC. That is, there may be a need for a method of performing control such that the magnitude of the signal output from the CTLE to the DFE falls within the allowable voltage range of the DAC.

<FIG> is a view showing the physical layer of an external device interface according to an embodiment of the present disclosure.

The external device interface <NUM> of the signal receiving apparatus <NUM> according to the embodiment of the present disclosure may be an HDMI interface, but this is only an example and is not limited thereto. In the present disclosure, it is assumed that the external device interface <NUM> is an HDMI interface, but this is only for convenience of description.

As shown in <FIG>, the physical layer of the HDMI interface may include at least some or all of one or more equalizers <NUM> and <NUM>, a detector <NUM> and a processor <NUM>.

The equalizers <NUM> and <NUM> may reduce inter-symbol interference of the signal received through the HDMI terminal.

The detector <NUM> may detect the swing level of an output signal output from the first equalizer <NUM> to the second equalizer <NUM>.

The processor <NUM> may control the equalizers <NUM> and <NUM> and the detector <NUM>. For example, the processor <NUM> may adjust the swing level of the output signal output from the first equalizer <NUM> to the second equalizer <NUM>.

In particular, according to the present disclosure, the processor <NUM> may control at least some or all of the equalizers <NUM> and <NUM> or the detector <NUM>, such that the swing level of the output signal output from the equalizers <NUM> and <NUM> is constantly maintained in a preset range.

More specifically, the equalizers <NUM> and <NUM> include the first equalizer <NUM> and the second equalizer <NUM>, the first equalizer <NUM> may be a signal amplification linear equalizer, and the second equalizer <NUM> may be a non-linear equalizer for eliminating non-amplification bit interference (ISI). For example, the first equalizer <NUM> may be a continuous time linear equalizer (CTLE) and the second equalizer <NUM> may be a decision feedback equalizer (DFE), but this is only an example and is not limited thereto.

The first equalizer <NUM> may amplify a signal input through a terminal, and the second equalizer <NUM> may reduce inter-symbol interference in a signal output from the first equalizer <NUM> to the second equalizer <NUM>. At this time, the swing level of the signal output from the first equalizer <NUM> to the second equalizer <NUM> may fall within a preset range, and the preset range may include the allowable voltage range of the DAC in the second equalizer <NUM>. For example, the preset range may be <NUM> mV to <NUM> V, but this is only an example and is not limited thereto.

Meanwhile, the processor <NUM> may adjust the swing level of the output signal output from the first equalizer <NUM> to the second equalizer <NUM>. That is, the processor <NUM> may adjust the equalizer gain of the first equalizer <NUM> such that the swing level of the output signal output from the first equalizer <NUM> falls within the preset range.

First, the equalizer gain will be described with reference to <FIG>.

<FIG> is a circuit diagram of a continuous time linear equalizer (CTLE).

When the first equalizer <NUM> is a CTLE as shown in <FIG>, a transfer function H(s) and the positions of zero and pole may be calculated as follows. <MAT> <MAT>.

Therefore, DC gain and ideal peak gain may be calculated as follows.

Accordingly, an ideal peak index may be calculated as follows.

The resistor and capacitor of the CTLE may be designed as variable elements. As the values of the resistors and the capacitor are adjusted, the positions of the zero and pole are changed and thus equalizer gain may be adjusted.

Such equalizer gain may include DC gain and AC gain, and signal amplification is determined by the DC gain and the AC gain.

The DC gain is a gain value at a zero frequency in a CTLE transfer function and may be Rs. The AC gain is a gain value at a peak frequency in a CTLE transfer function and may be Cs. Rs and Cs may be adjusted by the operating method of the CTLE.

Accordingly, the processor <NUM> may first determine DC gain for enabling the swing level of the signal output from the first equalizer <NUM> to fall within a preset range, by adjusting the DC gain. When the DC gain is determined, the AC gain may be determined by performing error profile while adjusting the AC gain with respect to the determined DC gain.

To this end, the detector <NUM> may detect the swing level of the output signal output from the first equalizer <NUM>. The processor <NUM> may adjust the swing level of the output signal such that the swing level of the output signal output from the first equalizer <NUM> falls within the preset range based on the result of detection of the detector <NUM>.

When the swing level of the output signal output from the first equalizer <NUM> does not fall within the preset range based on the result of detection of the detector <NUM>, the processor <NUM> may determine the DC gain by stepwise changing the DC gain until the swing level of the output signal falls within the preset range. A series of operations may be referred to as a DC gain scan function.

Hereinafter, a detailed method will be described with reference to <FIG>.

<FIG> is a flowchart illustrating a method of operating a signal receiving apparatus according to an embodiment of the present disclosure.

First, the DC gain and the AC gain may be set to a default DC gain value and a default AC gain value, respectively. For example, the default DC gain value and the default AC gain value may be respectively <NUM> dB and <NUM> dB, but this is only an example and is not limited thereto.

The processor <NUM> may detect the swing level of the output signal output from the first equalizer <NUM> to the second equalizer <NUM> (S11).

That is, the processor <NUM> may detect the swing level of the signal processed by the first equalizer <NUM> through the detector <NUM>.

The processor <NUM> may determine whether the swing level of the output signal falls within the preset range (S13).

That is, the processor <NUM> may determine whether the swing level of the signal output from the first equalizer <NUM> detected by the detector <NUM> falls within the preset range. Here, the preset range may be the allowable voltage range of the DAC in the second equalizer <NUM>. For example, the preset range may be <NUM> mV to <NUM> V, but this is only an example and is not limited thereto.

When the swing level of the output signal does not fall within the preset range (S15), the processor <NUM> may determine whether the swing level of the output signal is less than the preset range (S17).

For example, when the predetermined range is <NUM> mV to 1V, the processor <NUM> may determine whether the swing level of the output signal is less than <NUM> mV. That is, the processor <NUM> may determine whether the swing level of the output signal is less than a minimum value of the preset range.

When the swing level of the output signal is less than the preset range, the processor <NUM> may increase the DC gain value (S19).

For example, the processor <NUM> may increase the DC gain value by adding a reference value (e.g., <NUM> dB) to the current DC gain value. Here, the reference value is only an example and is not limited thereto.

The processor <NUM> may determine whether the swing level of the output signal is included in the preset range after increasing the DC gain value (S13).

Meanwhile, when the swing level of the output signal is greater than the preset range, the processor <NUM> may decrease the DC gain value (S19).

For example, when the swing level of the output signal is greater than a maximum value of the preset range, the processor <NUM> may decrease the DC gain value.

For example, the processor <NUM> may decrease the DC gain value by subtracting a reference value (e.g., <NUM> dB) from the current DC gain value. Here, the reference value is only an example and is not limited thereto.

The processor <NUM> may determine whether the swing level of the output signal falls within the preset range after decreasing the DC gain value (S13).

When the swing level of the signal output from the first equalizer <NUM> is greater than the preset range, the processor <NUM> may stepwise decrease the DC gain value until the swing level of the signal output from the first equalizer <NUM> falls within the predetermined range. On the contrary, when the swing level of the signal output from the first equalizer <NUM> is less than the preset range, the processor <NUM> may stepwise increase the DC gain value until the swing level of the signal output from the first equalizer <NUM> falls within the predetermined range.

That is, the processor <NUM> may determine the DC gain of the first equalizer <NUM> such that the swing level of the output signal falls within the preset range.

When the swing level of the signal output from the first equalizer <NUM> falls within the preset range, the processor <NUM> may determine the DC gain as a current DC gain value (S23).

Therefore, the swing level of the output signal output from the first equalizer <NUM> to the second equalizer <NUM> may fall within the preset range.

<FIG> is a view showing a state in which the swing level of the signal output from the CTLE according to the embodiment of the present disclosure is adjusted.

As shown in (a) of <FIG>, when the swing level of the signal input to the first equalizer <NUM> is <NUM> V, the processor <NUM> may adjust the swing level of the signal output from the first equalizer <NUM> to the second equalizer <NUM> to <NUM> mV, by changing the DC gain.

Alternatively, as shown in (b) of <FIG>, when the swing level of the signal input to the first equalizer <NUM> is <NUM> V, the processor <NUM> may adjust the swing level of the signal output from the first equalizer <NUM> to the second equalizer <NUM> to <NUM> mV, by changing the DC gain.

That is, the processor <NUM> may adjust the DC gain such that the swing level of the signal output from the first equalizer <NUM> to the second equalizer <NUM> falls within the preset range (or the preset level), regardless of the swing level of the signal input to the first equalizer <NUM>.

When the DC gain is determined, the processor <NUM> may adjust AC gain with respect to the determined DC gain (S25).

Specifically, when the DC gain is determined, the processor <NUM> may determine the AC gain by detecting the error rate of the output signal with respect to the determined DC gain. That is, the processor <NUM> may detect the error rate of each AC gain with respect to the determined DC gain, and select AC gain with a lowest error rate. Therefore, the processor <NUM> may acquire AC gain for maximizing the eye open area of the output signal.

For example, when the DC gain is determined, the processor <NUM> may detect the error rate of each AC gain value while adjusting the AC gain value and determine an AC gain value having a smallest error rate as AC gain.

Error rate detection may include various methods such as a method of counting TMDS (Transition Minimized Differential Signaling) errors, a method of detecting BCH (Bose, Chaudhri, Hocquenghem Code) or ECC (Error Check and Correct Memory) errors, etc..

The first equalizer <NUM> may perform signal processing according to the DC gain and AC gain determined by the above-described method.

That is, the equalizers <NUM> and <NUM> may compensate for the signal received through the terminal according to the DC gain and AC gain determined using the above-described method.

(a) of <FIG> is an eye diagram of a signal output from a conventional signal processing apparatus, and (b) of <FIG> is an eye diagram of a signal output from a signal processing apparatus according to an embodiment of the present disclosure.

(a) and (b) of <FIG> may show the result of measuring signals output when signals having different swing levels (e.g., Signal <NUM> having a swing level of <NUM> mV, Signal <NUM> having a swing level of <NUM> mV and Signal <NUM> having a swing level of <NUM> mV) are input to the conventional signal receiving apparatus and the signal receiving apparatus according to the embodiment of the present disclosure. That is, (a) and (b) of <FIG> may show results of measuring wavelengths through equipments (e.g., a CTS test equipment and a generator) on a PCB pattern.

Since the equalizer of the conventional signal receiving apparatus does not separately adjust DC gain, an input signal is processed according to predetermined DC gain and thus the change width of the swing level of the signal output from the signal processing apparatus may be large as shown in (a) of <FIG>. Referring to the detailed example shown in (a) of <FIG>, the swing level of Signal <NUM> may be less than VDAC (the allowable voltage range of the digital-to-analog converter (DAC)), the swing level of Signal <NUM> may be equal to VDAC, and the swing level of Signal <NUM> may be greater than VDAC. In this case, signal compensation performance of the signal processing apparatus for Signal <NUM> and Signal <NUM> is lower than signal compensation performance of the signal processing apparatus for Signal <NUM>. Therefore, it may be difficult to restore required signal quality.

Meanwhile, since the equalizer of the signal apparatus according to the embodiment of the present disclosure adjusts the swing level of the output signal to be included in VDAC by adjusting DC gain according to the swing level of the input signal, as shown in (b) of <FIG>, the swing levels of the output signals may be constantly maintained in the VDAC range (e.g., <NUM> mV to <NUM> V). Accordingly, the signal processing apparatus according to the present disclosure is advantageous in that signal compensation performance is guaranteed regardless of the swing level of the input signal and required signal quality can be restored.

Accordingly, the signal apparatus according to the present disclosure has an advantage of improving responsiveness to various source apparatus and various cables. That is, according to the present disclosure, flexible signal process is possible regardless of the magnitude of the signal transmitted from the source apparatus or the length of the cable.

The present disclosure may be embodied as computer-readable codes on a program-recorded medium. The computer-readable recording medium may be any recording medium that stores data which can be thereafter read by a computer system. Examples of the computer-readable medium may include hard disk drive (HDD), solid state disk (SSD), silicon disk drive (SDD), read-only memory (ROM), random-access memory (RAM), CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device. In addition, the computer may include the controller <NUM> of the display device <NUM>. Accordingly, the above detailed description should not be construed as being restrictive in all respects and should be considered illustrative.

The above description is merely illustrative of the technical idea of the present invention, and various modifications and changes may be made thereto by those skilled in the art without departing from the essential characteristics of the present invention.

Therefore, the embodiments of the present invention are to illustrate the technical idea of the present invention.

Claim 1:
A signal receiving apparatus comprising:
a terminal configured to receive a signal from an external device; and
a first equalizer configured to amplify the signal received through the terminal and a second equalizer configured to reduce inter-symbol interference in a signal output from the first equalizer, wherein the first equalizer is a continuous time linear equalizer, CTLE, and the second equalizer is a decision feedback equalizer, DFE,
wherein a swing level of an output signal output from the first equalizer to the second equalizer is maintained in a preset range, wherein DC gain of an input signal input to the first equalizer is adjusted so that the swing level of the signal output from the first equalizer to the second equalizer falls within the preset range,
wherein the adjusting DC gain of an input signal input to the first equalizer comprises:
detecting (S11) a swing level of an output signal output from the first equalizer to the second equalizer,
determining (S13) whether the detected swing level of the output signal falls within the preset range,
if the swing level of the output signal does not fall within the preset range, determining (S17) whether the swing level of the output signal is smaller than the preset range, and increasing (S19) or decreasing (S21) the DC gain value by adding or subtracting a reference value from the current DC gain value until the swing level of the output signal falls within the preset range,
if the swing level of the output signal falls within the preset range, determining (S23) the DC gain as a current DC value,
determining (S25) AC gain with respect to the determined DC gain by performing an error profile while adjusting the AC gain with respect to the determined DC gain and
performing signal processing according to the determined DC gain and the determined AC gain,
characterized in that the determining (S25) AC gain with respect to the determined DC gain by performing an error profile while adjusting the AC gain with respect to the determined DC gain comprises:
detecting an error rate of an AC gain value with respect to the determined DC gain,
varying the AC gain value according to capacitances (Cs) of a capacitor of the first equalizer associated with the AC gain and detecting an error rate of each of the varied AC gain value with respect to the determined DC gain, and
selecting the AC gain value with a lowest error rate.