KR20200102677A - Apparatus and method of adaptive equalization - Google Patents

Abstract

The present invention proposes an adaptive equalization device and a method thereof which optimizes digital algorithms, resists dynamic environment changes, and can adjust a monitoring range according to a signal level. The proposed device comprises: a first equalization filter which compensates and outputs a component of a high frequency band of a reception signal; a second equalization filter installed in parallel with the first equalization filter and monitors the reception signal; a size comparison unit for sampling the size of a monitoring signal from the second equalization filter for each cycle of an asynchronous clock signal; and a digital control unit which collects comparison data from the size comparison unit by changing an equalizer monitoring code to be provided to the second equalization filter and a reference signal of the size comparison unit, finds the optimal equalizer control code based on the collected comparison data, and provides the optimal equalizer control code to the first equalization filter.

Description

Apparatus and method of adaptive equalization

The present invention relates to an adaptive equalization apparatus and a method thereof, and more particularly, to an adaptive equalization apparatus and a method for detecting a distorted level to output an optimal signal.

The equalizer compensates for attenuation or distortion of a signal generated in the process of transmitting a signal using a predetermined channel.

In general, an equalizer technology used in a high-speed adaptive equalizer is designed in various structures such as a decision feedback equalizer and a tap-delay line filter.

Meanwhile, in order to effectively compensate for changes in channel characteristics according to a process or temperature change, various techniques are applied to the fast adaptive equalizer. For example, in a conventional high-speed adaptive equalizer, the power of the high-frequency component of the equalization filter output signal is compared with the power of the high-frequency component of the reference signal, and the high-frequency voltage gain of the equalization filter is adjusted to minimize the power difference.

Accordingly, an adaptive equalization device (Republic of Korea Patent Registration No. 10-1074454) that does not require a high-speed clock generator to reduce power consumption has been applied for a patent and has been registered.

The adaptive equalization apparatus of Korean Patent Registration No. 10-1074454 described above extracts a histogram from a received signal, calculates a Q-factor, and then evaluates the transmission quality of the signal. Since the maximum value on the histogram is the largest in the optimal equalization state, it is determined that the Q-factor at this time is the best, and the current state is set to the optimal state and applied to the equalizer. By sampling with an out-of-sync clock, you can read the magnitude of the voltage at any point.

In addition, the adaptive equalization apparatus of Korean Patent Registration No. 10-1074454 described above records a small number of times compared to the comparison voltage while randomly sampling the input signal. The recorded results appear in the form of a cumulative density function (CDF).

However, since the adaptive equalization device of Korean Patent Registration No. 10-1074454 described above stores the entire data for the accumulated density function (CDF) until the adaptation is completed, there is a problem that the digital circuit area increases by using a lot of registers. have.

In addition, the adaptive equalization device of Korean Patent Registration No. 10-1074454 described above has a problem in that the signal is distorted by monitoring the signal. In other words, since all equalizer control codes must be monitored to find the optimum signal, the change of the equalizer control code is immediately reflected in the output signal. Due to this, the fields that can be applied are limited. It is fixed as initially calibrated, so it cannot keep up with the dynamic changes of the environment.

In addition, the adaptive equalization apparatus of Korean Patent Registration No. 10-1074454 described above has a problem that the signal size affects the accuracy. In other words, if the input signal is too small, the discrimination power of the histogram decreases, so the size of the minimum resolution must be reduced. If the input signal is too large, the histogram is not properly observed, so the maximum observation range must be increased. In order to satisfy these two conditions, it is necessary to observe the signal in a wide range while observing the signal in detail, so it takes a long time to complete the adaptation and the size of the monitoring circuit increases.

Prior Art 1: Korean Patent Registration No. 10-1074454 (adaptive equalization device and equalization method)

The present invention has been proposed to solve the above-described conventional problems, and is to provide an adaptive equalization apparatus and method capable of optimizing a digital algorithm, strong against dynamic environmental changes, and adjusting a monitoring range according to a signal size. have.

In order to achieve the above object, an adaptive equalization apparatus according to a preferred embodiment of the present invention includes: a first equalization filter for compensating and outputting a component of a high frequency band of a received signal; A second equalization filter installed in parallel with the first equalization filter and monitors the received signal; A magnitude comparison unit for sampling the magnitude of the monitoring signal from the second equalization filter for each period of the asynchronous clock signal; And changing the equalizer monitoring code to be provided to the second equalization filter and the reference signal of the size comparison unit, collecting the comparison data from the size comparison unit, and finding an optimal equalizer control code based on the collected comparison data. A digital control unit for providing the first equalization filter to the first equalization filter, wherein the second equalization filter enables the digital control unit to find an optimal equalizer control code, according to the equalizer monitoring code of the digital control unit. The received signal is compensated and output.

The size comparison unit may include a reference signal generator for generating a reference signal of an analog component corresponding to a reference signal control code from the digital control unit; An analog comparison unit calculating a difference between a monitoring signal from the second equalization filter and a reference signal from the reference signal generation unit and outputting an analog signal; And a sampling circuit unit for sampling and digitizing the output from the analog comparison unit every cycle of the received asynchronous clock signal.

The reference signal control code is a code for determining the level of the reference signal, and may be any one of N codes having different levels.

The digital control unit adjusts the size of the input signal so that the input signal becomes a specific reference signal range, and after the adjustment is completed, the digital control unit changes the equalizer monitoring code of the second equalization filter or the reference signal of the size comparison unit. A peak value of is calculated, and an optimal equalizer control code found based on the calculated peak value may be applied to the first equalization filter.

On the other hand, the adaptive equalization method according to a preferred embodiment of the present invention includes a first equalization filter for compensating and outputting a component of a high frequency band of a received signal, and is installed in parallel with the first equalization filter, and monitors the received signal. A second equalization filter, a size comparison unit that samples the size of the monitoring signal from the second equalization filter for each cycle of the asynchronous clock signal, and an equalizer monitoring code to be provided to the second equalization filter and the size comparison unit Adaptation of an adaptive equalization device including a digital control unit that collects comparison data from the size comparison unit while changing signals and provides the best equalizer control code to the first equalization filter based on the collected comparison data As a type equalization method,

Adjusting the size of the input signal so that the input signal received by the size comparison unit becomes a specific reference signal range; And calculating a peak value of the histogram by changing the equalizer monitoring code of the second equalization filter or the reference signal of the magnitude comparison unit, and calculating the optimal equalizer control code found based on the calculated peak value. 1 applying to an equalization filter; and.

And moving to a standby mode when the input signal to the adaptive equalization device is too small, and moving to a standby mode when the applying step is completed.

The adjusting may include setting an amplification gain of the second equalization filter to a minimum; Setting the reference signal as the middle of the reference signal and then collecting N sampling results by the magnitude comparison unit; If all of the sampling results are high, setting the reference signal to the middle of the + reference signal and collecting N sampling results by the magnitude comparison unit; Determining whether a current amplification gain is maximum if the results of N sampling times by the magnitude comparison unit are all low after setting the reference signal to the middle of the + reference signal; And if the current amplification gain is not the maximum, increasing the current amplification gain, setting the reference signal to the middle of the reference signal and returning to the step of collecting N sampling results by the size comparison unit. Can include.

After setting the reference signal to the middle of the -reference signal, all N sampling results in the magnitude comparison unit are not high, or the magnitude comparison unit after setting the reference signal to the middle of the +reference signal If all of the N sampling results are not low, the step of applying may be performed and the operation of the corresponding step may be performed.

If the current amplification gain is maximum, the standby mode can be entered.

The adjusting may include setting a reference signal range in the size comparison unit to a maximum; Setting the reference signal as the middle of the reference signal and then collecting N sampling results by the magnitude comparison unit; If all of the sampling results are high, setting the reference signal to the middle of the + reference signal and collecting N sampling results by the magnitude comparison unit; Determining whether a range of a current reference signal is a minimum if all N sampling results by the magnitude comparison unit are low after setting the reference signal to the middle of the + reference signal; And if the range of the current reference signal is not the minimum, reducing the range of the current reference signal and setting the reference signal to the middle of the reference signal, returning to the step of collecting N sampling results by the magnitude comparison unit. Can include.

After setting the reference signal to the middle of the -reference signal, all N sampling results in the magnitude comparison unit are not high, or the magnitude comparison unit after setting the reference signal to the middle of the +reference signal If all of the N sampling results are not low, the step of applying may be performed and the operation of the corresponding step may be performed.

If the range of the current reference signal is the minimum, the standby mode may be entered.

The applying may include setting K as an equalizer monitoring code to 0 (zero), S as a reference signal control code to 0 (zero), a maximum peak to 0 (zero), and an optimal code to 0 (zero); Inputting a K-th equalizer monitoring code to the second equalization filter; Generating a reference signal corresponding to the S-th reference signal control code, collecting the results of performing X-time sampling by the size comparison unit, and counting a high number of the collected sampling results; Determining whether an absolute value of the difference between the counted current counting value and the previous counting value is greater than the maximum peak; If the absolute value of the difference between the current counting value and the previous counting value is greater than the maximum peak, the maximum peak is replaced with an absolute value of the difference between the current counting value and the previous counting value, and the optimal code is monitored by the current equalizer. Replacing the code with a value, and replacing the previous counting value with the current counting value; Determining whether the value of the reference signal control code is a maximum value of a preset reference signal control code; If the value of the reference signal control code is the maximum value of the reference signal control code, determining whether the value of the equalizer monitoring code is the maximum value of the preset equalizer monitoring code; And if the value of the equalizer monitoring code is the maximum value of the preset equalizer monitoring code, reflecting the optimal code as an optimal equalizer control code to the first equalization filter.

If the absolute value of the difference between the current counting value and the previous counting value is not greater than the maximum peak, the previous counting value may be replaced with the current counting value without replacing the maximum peak and the optimal code.

As a result of the determination in the step of determining whether the value of the reference signal control code is the maximum value of the preset reference signal control code, if the value of the reference signal control code is not the maximum value of the reference signal control code, the reference signal control code By adding a value to +1, the step of generating a reference signal corresponding to the S-th reference signal control code, collecting the results of performing X-time sampling in the size comparison unit, and counting the high number of the collected sampling results can be moved. have.

As a result of the determination in the step of determining whether the value of the equalizer monitoring code is the maximum value of the preset equalizer monitoring code, if the value of the equalizer monitoring code is not the maximum value of the preset equalizer monitoring code, the equalizer monitoring The code value is +1, and the step of inputting the K-th equalizer monitoring code to the second equalization filter may be performed.

In the standby mode, when it is determined that there is no signal in the adjusting step, the power of the first equalization filter may be turned off.

In the standby mode, power of the second equalization filter and the size comparison unit may be turned off after the applying step.

According to the present invention having this configuration, the area of the digital control unit can be further reduced by optimizing the algorithm of the digital control unit.

By adding an equalization filter dedicated to signal monitoring, the digital control unit changes the algorithm to continuously adapt the equalizer, which makes it strong even in dynamic environmental changes.

The monitoring range can be adjusted according to the signal level, and a signal detector function can be performed by adding an input signal size determination function to the digital control unit.

1 is a block diagram of an adaptive equalization apparatus according to an embodiment of the present invention.
2 is an internal configuration diagram of a size comparison unit illustrated in FIG. 1.
3 and 4, and FIGS. 5A and 5B are diagrams applicable to explanation of the size comparison unit shown in FIG. 1.
6 is a diagram illustrating an adaptive equalization method according to an embodiment of the present invention.
7 to 13 are diagrams for explaining an input signal level determination step shown in FIG. 6.
14 to 16 are diagrams for explaining a step of observing the characteristics of the equalization filter shown in FIG. 6.

In the present invention, various modifications may be made and various embodiments may be provided, and specific embodiments will be illustrated in the drawings and described in detail.

However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate an overall understanding, the same reference numerals are used for the same elements in the drawings, and duplicate descriptions for the same elements are omitted.

1 is a block diagram of an adaptive equalization apparatus according to an embodiment of the present invention.

An adaptive equalization apparatus according to an embodiment of the present invention includes a first equalization filter 10, a second equalization filter 20, a size comparison unit 30, and a digital control unit 40.

The first equalization filter 10 may compensate and output a component of a high frequency band of an actually received signal. The first equalization filter 10 receives an equalizer control code from the digital control unit 40. The first equalization filter 10 may select an equalization coefficient in response to an equalizer control code and perform equalization with an equalization gain corresponding to the selected equalization coefficient.

The second equalization filter 20 is installed in parallel with the first equalization filter 10 at the reception signal terminal.

Like the first equalization filter 10, the second equalization filter 20 has a function of compensating and outputting the components of the high-frequency band of the received signal, so that the second equalization filter 20 and the first equalization filter 10 It can be said that it has the same operating characteristics.

Meanwhile, the second equalization filter 20 may be referred to as an equalization filter dedicated to signal monitoring. The second equalization filter 20 performs monitoring to find an optimal equalizer control code capable of compensating the received signal in an optimal state according to the equalizer monitoring code of the digital controller 40.

That is, the second equalization filter 20 may compensate and output the received signal according to the equalizer monitoring code of the digital controller 40 in order to allow the digital controller 40 to find an optimal equalizer control code. . In addition, the signal output from the second equalization filter 20 may be referred to as a monitoring signal.

The above-described first equalization filter 10 and second equalization filter 20 may each include an input signal terminal, an output signal terminal, a low frequency gain control terminal, and a high frequency gain control terminal. Here, the low-frequency gain control terminal receives a signal for controlling the amount of amplifying the low-frequency band of the signal, and the high-frequency gain control terminal receives a signal for controlling the amount of amplifying the high-frequency band of the signal. Low-frequency gain control is capable of controlling the amplitude of an input signal and can control amplification gain. The high frequency gain control is capable of controlling the transition speed of an input signal and can change the waveform of the signal itself.

The equalizer control code of the digital controller 40 is input to the low frequency gain control terminal or the high frequency gain control terminal of the first equalization filter 10 according to the situation. Then, the equalizer monitoring code of the digital control unit 40 is input to the low frequency gain control terminal or the high frequency gain control terminal of the second equalization filter 20 according to the situation. That is, for the amplification gain of the input signal of the second equalization filter 20, a predetermined equalizer monitoring code will be input to the low frequency pie gain control stage. In the case of changing the waveform itself of the input signal of the second equalization filter 20 (to control the transition speed of the signal), a predetermined equalizer monitoring code will be input to the high frequency gain control terminal.

The size comparison unit 30 receives a predetermined clock signal (eg, asynchronous clock), receives a monitoring signal from the second equalization filter 20, and receives a reference signal control code from the digital controller 40.

Accordingly, the size comparison unit 30 measures (samples) the size of the input signal (monitoring signal) from the second equalization filter 20 for each cycle of the received clock signal (asynchronous clock). In other words, the size comparison unit 30 may sample an input signal for each cycle of a clock signal (asynchronous clock) and compare it with a digitally controlled reference voltage to digitally output high/low. A more detailed description of the size comparison unit 30 will be described later.

The digital control unit 40 provides an equalizer control code to the first equalization filter 10, an equalizer monitoring code (also referred to as a high frequency band gain control code) to the second equalization filter 20, and controls a reference signal. The code may be provided to the size comparison unit 30.

The digital control unit 40 collects the comparison data from the size comparison unit 30 by changing the equalizer monitoring code to be provided to the second equalization filter 20 and the reference signal of the size comparison unit 30, and compares the collected data. Based on the data, the activity to find the optimal equalizer control code is continuously performed. The found optimal equalizer control code is applied to the first equalization filter 10.

That is, the digital control unit 40 provides an equalizer monitoring code to be provided to the second equalization filter 20 (for example, it may be referred to as a high-frequency band gain code input to the high-frequency gain control terminal) and the size comparison unit 30. By changing the reference signal control code to be provided to each time, the number of high comparison data is counted. In addition, the digital control unit 40 calculates the difference between the current counting value and the previous counting value, determines the highest peak value in the probability density function (PDF) optimally, and determines the corresponding equalizer control code as a first equalization filter 10 ) Can be provided.

In other words, the digital control unit 40 adjusts the size of the input signal received from the corresponding adaptive equalization device, and observes the characteristics of the second equalization filter 20 based on this code for the optimal high-frequency band gain ( That is, the equalizer control code) may be applied to the first equalization filter 10.

FIG. 2 is an internal configuration diagram of the size comparison unit 30 shown in FIG. 1, and FIGS. 3 and 4, and FIGS. 5A and 5B are diagrams applicable to the description of the size comparison unit 30 shown in FIG. .

The size comparison unit 30 may include a reference signal generation unit 31, an analog comparison unit 32, and a sampling circuit unit 33.

The reference signal generator 31 generates a reference signal (also referred to as a reference voltage) of an analog component corresponding to the reference signal control code from the digital control unit 40. Here, the reference signal control code is a code for determining the level of the reference voltage, and may be, for example, any one of about 16 codes having different levels.

Accordingly, the reference signal control code applied to the reference signal generator 31 may be any one of about 16 codes having different levels. In addition, the reference signal output from the reference signal generator 31 varies according to the reference signal control code.

The analog comparison unit 32 obtains a difference between an input signal (ie, a monitoring signal from the second equalization filter 20) and a reference signal from the reference signal generation unit 31 and outputs an analog signal.

The sampling circuit unit 33 samples and digitizes the output from the analog comparison unit 32 every cycle of an input clock signal (eg, asynchronous clock). Accordingly, the sampling circuit unit 33 outputs predetermined digital data (eg, high or low).

Here, the clock signal is a signal that provides a time point at which the comparison is to be performed, and generally, a rising edge or a falling edge may be used.

In FIG. 2, the analog comparison unit 32 and the sampling circuit unit 33 are configured separately, but can be integrated if necessary.

The size comparison unit 30 configured as described above compares the size of the input signal with the internally generated reference signal as shown in FIG. 3. Then, the size comparison unit 30 samples the clock signal for each period, determines the size, and outputs digital data corresponding thereto. The reference signal to be compared depends on the control.

Meanwhile, as shown in FIG. 4, the size comparison unit 30 may be implemented by making a difference obtained by subtracting the reference signal from the input signal into a signal and comparing it based on zero.

Unlike the case in which only the center of data is sampled with the synchronous clock of FIG. 5A, the size comparison unit 30 may randomly sample the input signal when the asynchronous clock is input as shown in FIG. 5B. In this case, the probability that the input signal is high/low is 50:50. Since sampling is not performed at a specific time point of each input signal bit, a sampling value at a random time point can be obtained. Although there is no data at the time of sampling, data on the distribution of the sampled voltage (that is, the number of high and low comparison data can be counted) can be obtained.

If it is an asynchronous clock, random sampling is performed, so a low-speed clock can be used. That is, compared to the case where only the center of the data is sampled with the synchronous clock of FIG. 5A, when a low-speed asynchronous clock is used as shown in FIG. 5B, the burden on the operation speed is reduced, and thus power consumption and the size of the circuit may be reduced. .

6 is a diagram illustrating an adaptive equalization method according to an embodiment of the present invention.

The adaptive equalization method according to an embodiment of the present invention includes determining the input signal size (S100), observing the characteristics of the equalization filter (S200), and waiting for power consumption reduction (S300). , Has a circular structure. The adaptive equalization method according to an embodiment of the present invention is performed in the adaptive equalization apparatus described with reference to FIGS. 1 to 5.

In the input signal level determination step (S100), the range of the input signal received from the adaptive equalization device (that is, the signal input to the size comparison unit 30 (monitoring signal)) and the range of the reference signal generated therein are determined. After comparison, the size of the input signal is adjusted so that the input signal is approximately 1/2 of the range of the reference signal. When the size adjustment of the input signal is finished, the process moves to the equalization filter characteristic observation step (S200). If the input signal is too small, it is considered as no signal and moves to the standby step (S300). Here, the input signal size determination step (S100) may be referred to as an input signal size adjustment step.

The reason for adjusting the size of the input signal so that the input signal is approximately 1/2 of the reference signal range (i.e., between the maximum and minimum values of the reference signal) in the input signal size determination step (S100) is that the input signal is too large. If it is smaller than or equal to, the accuracy in the equalization filter characteristic observation step (S200) is degraded. That is, when the input signal is approximately 1/2 of the range of the reference signal, the characteristics of the second equalization filter 30 to be monitored can be better observed, so that the optimal equalizer control code is determined by the first equalization filter 10. Can be provided to.

In the equalization filter characteristic observation step (S200), the peak value of the histogram is calculated by changing the high frequency band gain or the reference signal of the second equalization filter 20, and the optimum found using the second equalization filter 20 A code (ie, an equalizer control code) for a gain in a high frequency band of is applied to the first equalization filter 10. Thereafter, a flag indicating that the adaptation of the adaptive equalizer is complete is displayed and the process moves to a standby step S300. Here, the equalization filter characteristic observation step (S200) may be referred to as an equalizer control code application step.

In the standby step S300 (that is, the standby mode), the power of the second equalization filter 20 and the size comparison unit 30 is turned off in order to reduce power consumption after the equalization filter characteristic observation step S200. In addition, when it is found that there is no signal in the input signal level determination step S100, the power of the first equalization filter 10 is also turned off. After a certain period of time has elapsed, the flow moves to the input signal size determination step S100.

The above-described input signal size determination step (S100), equalization filter characteristic observation step (S200), and standby step (S300) may be sufficiently performed under the supervision of the digital controller 40.

7 to 13 are diagrams for explaining the input signal level determination step S100 shown in FIG. 6.

If the input signal input to the adaptive equalization apparatus according to an embodiment of the present invention is too large or too small, the accuracy in the equalization filter characteristic observation step (S200) is degraded. Accordingly, it is preferable to adjust the input signal or the range of the reference signal so that the size of the input signal is approximately ½ of the reference signal range in the input signal size determination step S100. If the input signal is too small, it is determined that there is no signal to enter the standby mode (that is, the standby step S300).

In the input signal size determination step S100, a +/- reference signal having the same size based on 0 (zero) is used as shown in FIG. 7. As shown in FIG. 7, when the input signal is compared with the reference signal of -, the comparison values of the size comparison unit 30 are all high, and when the input signal is compared with the reference signal of +, the size comparison unit 30 If all of the comparison values of are low, the digital control unit 40 may determine that the range of the corresponding input signal is smaller than the range of the reference signal. Meanwhile, as shown in FIG. 8, when the opposite value starts to be mixed with the comparison value in the size comparison unit 30, the digital control unit 40 may determine that the range of the input signal is larger than the range of the reference signal.

In this way, in order to compare the input signal and the reference signal to determine the size of the input signal, a method of gradually increasing the amplification gain of the second equalization filter 20 or a method of reducing the range of the reference signal may be adopted.

First, a case of using a method of finding a gain larger than the reference signal while gradually increasing the amplification gain of the second equalization filter 20 will be described with reference to FIG. 9. In FIG. 9, while increasing the amplification gain of the second equalization filter 20, an initial gain that is greater than the reference signal is found. That is, if the amplification gain of the second equalization filter 20 is increased by one step, the first code that becomes larger than the middle of the +/- reference signal (that is, the equalizer monitoring code input to the low frequency pie gain control stage) can be found. . When the first code that becomes larger than the middle of the +/- reference signal is found, it is selected and moves to the next step (ie, equalization filter characteristic observation step S200). If the amplification gain is made too large, the characteristics of the second equalization filter 20 cannot be observed. On the other hand, even if the gain of the amplifier is increased, if the input signal is not larger than the middle of the reference signal, it is determined that there is no signal.

This time, a case of using a method of reducing the range of the reference signal without increasing the amplification gain of the second equalization filter 20 will be described with reference to FIG. 10. In FIG. 10, while reducing the range of the reference signal without increasing the amplification gain of the second equalization filter 20, a code having an input signal larger than the middle of the reference signal range (ie, a reference signal control code) is found. If a code with an input signal larger than the middle of the range of the reference signal (i.e., reference signal control code) is found, the code (i.e., reference signal control code) is selected and the next step (i.e., equalization filter characteristic observation step (S200)) Go to. This method is relatively advantageous in terms of performance/implementation than the method of increasing the amplification gain. Even if the range of the reference signal is reduced to the minimum, if the input signal is smaller than the middle range of the reference signal, it is determined that there is no signal.

On the other hand, unlike in FIGS. 9 and 10 described above, it is possible to change only the code used by making the reference signal range compact without increasing the amplification gain of the second equalization filter 20 as shown in FIG. 11.

As a result, the input signal size determination step S100 may compare the size of the input signal while changing the size of the input signal or the range of the reference signal.

In the following, the case of comparing the size of the input signal by adjusting the amplification gain will be described again with reference to FIG. 12, and the case of comparing the size of the input signal by adjusting the range of the reference signal will be described again with reference to FIG. Explain once.

Referring to FIG. 12, first, the digital control unit 40 sets the amplification gain of the second equalization filter 20 to the minimum (S101), and sets "reference signal = -reference signal intermediate", and then the size comparison unit 30 ), the N sampling results are collected (S102). If the sampling result in step S102 (that is, the comparison value of the size comparison unit 30) is not all high, the digital control unit 40 moves to the equalization filter characteristic observation step S200.

If the sampling result in step S102 (that is, the comparison value of the size comparison unit 30) is all high (“Yes” in S103), the digital control unit 40 returns “reference signal = + reference signal intermediate” After setting to, the N sampling results in the size comparison unit 30 are collected (S104). If the sampling result in step S104 (that is, the comparison value of the size comparison unit 30) is all low ("Yes" in S105), the digital control unit 40 determines whether the current amplification gain is the maximum ( S106). If the current amplification gain is not the maximum, the digital control unit 40 returns to the above-described step S102 after increasing the current amplification gain (S107) and repeats the operation of the corresponding step.

If, in step S105, the sampling result (that is, the comparison value of the size comparison unit 30) is not all low, the digital control unit 40 moves to the equalization filter characteristic observation step (S200), and amplifies in step S106. If the gain is the maximum, the process moves to the standby step S300.

In this way, by gradually increasing the amplification gain of the second equalization filter 20 and finding a gain that is greater than the reference signal, the magnitude of the input signal can be compared.

Meanwhile, referring to FIG. 13, first, the digital control unit 40 sets the range of the reference signal in the size comparison unit 30 to the maximum (S111), and sets "reference signal = -reference signal intermediate" to compare the size. The N sampling results in the unit 30 are collected (S112). If the sampling result in step S112 (that is, the comparison value of the size comparison unit 30) is not all high, the digital control unit 40 moves to the equalization filter characteristic observation step S200.

If the sampling result in step S112 (that is, the comparison value of the size comparison unit 30) is all high (“Yes” in S113), the digital control unit 40 returns “reference signal = + reference signal intermediate” After setting to, the N sampling results in the size comparison unit 30 are collected (S114). If the sampling result in step S114 (that is, the comparison value of the size comparison unit 30) is all low ("Yes" in S115), the digital control unit 40 determines whether the range of the current reference signal is the minimum. Do (S116). If the current reference signal range is not the minimum, the digital control unit 40 reduces the current reference signal range (S117), returns to the above-described step S112, and repeats the operation of the corresponding step.

If, in step S115, the sampling result (that is, the comparison value of the size comparison unit 30) is not all low, the digital control unit 40 moves to the equalization filter characteristic observation step (S200), and the reference in step S116. If the signal range is the minimum, it moves to the standby step S300.

As described above, by adjusting the range of the reference signal of the size comparison unit 30 and enduring that the input signal is larger than the range of the reference signal, the size of the input signal can be compared.

14 to 16 are diagrams for explaining a step of observing the characteristics of the equalization filter shown in FIG. 6. Since the first equalization filter 10 and the second equalization filter 20 have the same characteristics, it is possible to observe the characteristics of the first equalization filter 10 simply by observing the characteristics of the second equalization filter 20. Can be.

Referring to FIG. 14, when the reference signal (that is, the reference voltage (Vref)) is lower than the input signal range, the count value is 0 (zero), and when the reference voltage is within the input signal range, the corresponding comparison data is By counting, the count value increases little by little. If the reference voltage goes above the input signal range, all of them are high, so the count value becomes the number of sampling. The counted value takes the form of a cumulative density function (CDF), and when the difference from the adjacent count value is calculated, it is expressed in the form of a probability density function (PDF). The probability density function (PDF) represents the probability that the input signal stays between each reference voltage and the reference voltage. Basically, the digital data of the size comparator 30 has a high or low value, and thus, there is a high probability of staying at a high or low voltage. As a result, the probability density function PDF has a peak value, as shown in FIG. 14.

Here, the size of the peak in the probability density function (PDF) varies depending on the excess/deficiency of the high frequency component as illustrated in FIG. 15. FIG. 15 shows how the adaptive equalizer finds the most optimal state depending on the case where the data transition speed is slow, too fast, or optimal. Here, when the data transition speed is slow, it is under-equalized in FIG. 15, when the data transition speed is too fast, it is over-equalized in FIG. 15, and the data transition speed is optimal (appropriate). Is the case of Optimum-equalized in FIG. 15.

For example, if the high frequency component is insufficient (i.e., under-equalized), the data transition moves more slowly than the optimal state (i.e., if it is Optimum-equalized), and thus the probability of staying at the intermediate value increases. This is because the probability density function (PDF) between high and low increases and the peak decreases. On the contrary, if the high frequency component is excessive (i.e., when it is over-equalized), it will bounce out more than High/Low at the data transition than in the optimal state (i.e., when it is Optimum-equalized). ) And the probability density function outside the low (PDF) increases, the peak decreases.

As the gain of the high frequency band of the second equalization filter 20 is changed as described above, a value having the largest peak on the probability density function PDF is optimal.

According to the equalization filter characteristic observation step (S200) in the present invention, the amount of data to be stored can be significantly reduced. In the prior art (Republic of Korea Patent Registration No. 10-1074454), probability density functions (PDF) were stored for all equalizer control codes and finally compared, but in the embodiment of the present invention, the comparison with the previous counting value This is because after calculating the difference, if it is the maximum, it is stored (recorded) and if it is not the maximum, it is immediately discarded.

In addition, in the prior art (Korean Patent Registration No. 10-1074454), the optimum value was found and terminated only once, but in the embodiment of the present invention, it was changed to circulate continuously. In the exemplary embodiment of the present invention, a second equalization filter 20 dedicated for monitoring is added, so that continuous equalization filter adaptation is possible.

Next, the above-described equalization filter characteristic observation step (S200) will be described in more detail with reference to FIG. 16.

First, the digital control unit 40 sets K = 0 (zero), S = 0 (zero), maximum peak = 0 (zero), optimal code = 0 (zero) (S201), and the second equalization filter 20 ), the K-th equalization filter high frequency band gain code is input (S202). Here, K may be an equalization filter high frequency band gain code (ie, an equalizer monitoring code applied to the second equalization filter 20), and S may be a reference signal control code.

Thereafter, the digital control unit 40 inputs the S-th reference signal control code to the size comparison unit 30 (S203). Accordingly, the size comparison unit 30 will generate a reference signal (reference voltage) corresponding to the S-th reference signal control code (ie, the 0-th reference signal control code).

Then, the digital control unit 40 collects the results of performing the X-times sampling performed by the size comparison unit 30, counts the high number of the collected sampling results, and temporarily stores the counting value (S204). For example, when the 0th reference signal control code is applied to the size comparison unit 30, the size comparison unit 30 compares the input signal with the reference signal corresponding to the 0th reference signal control code. The counting value (a value obtained by counting the high number) will be temporarily stored in the corresponding digital control unit 40.

Subsequently, the digital control unit 40 determines whether the absolute value of the difference between the current counting value and the previous counting value is greater than the maximum peak (S205).

If the absolute value of the difference between the current counting value and the previous counting value is greater than the maximum peak, the digital control unit 40 replaces the maximum peak with the absolute value of the difference between the current counting value and the previous counting value. (S206).

Then, the digital control unit 40 refers to the optimal code as the current K (S207), and the previous counting value as the current counting value (S208).

Meanwhile, as a result of the determination in step S205, if the absolute value of the difference between the current counting value and the previous counting value is not greater than the maximum peak, the digital controller 40 moves to step S208. In other words, after calculating the difference from the previous time after sampling X times, if it is the maximum, the temporarily stored counting value is recorded, and if it is not the maximum, it is immediately discarded.

Thereafter, the digital control unit 40 determines whether "S = N" (S209). Here, N denotes the maximum value of the reference signal control code. For example, N may be preset to “16”.

If it is not "S = N", the digital control unit 40 returns to step S203 after performing "S = S + 1" (S210) and repeats the operation of the step. If the reference signal control code is sequentially increased, the size comparison unit 30 will generate a reference signal (reference voltage) that increases sequentially.

Conversely, if "S = N", the digital control unit 40 determines whether "K = M" (S211). Here, M denotes the maximum value of the gain code in the high frequency band of the equalization filter. For example, M may be preset to "8".

If it is not "K = M", the digital control unit 40 returns to step S202 after performing "K = K + 1" (S212) and repeats the operation of the step.

Conversely, if "K = M", the digital control unit 40 reflects the optimal code to the first equalization filter 10 as the most optimal equalizer control code for the current state of the first equalization filter 10 (S213). . Accordingly, when the corresponding equalizer control code is applied to the first equalization filter 10, the adaptive equalization apparatus according to an embodiment of the present invention can be controlled to have an optimal equalization gain in real time.

As described above, an optimal embodiment has been disclosed in the drawings and specifications. Although specific terms have been used herein, these are only used for the purpose of describing the present invention, and are not used to limit the meaning or the scope of the present invention described in the claims. Therefore, those of ordinary skill in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the true technical scope of the present invention should be determined by the technical spirit of the appended claims.

10: first equalization filter
20: second equalization filter
30: size comparison unit
40: digital control unit

Claims (4)

A first equalization filter for compensating and outputting a component of a high frequency band of a received signal, a second equalization filter installed in parallel with the first equalization filter and monitoring the received signal, and the second for each cycle of an asynchronous clock signal A size comparison unit that samples the size of the monitoring signal from the equalization filter, and the equalizer monitoring code to be provided to the second equalization filter and the reference signal of the size comparison unit are changed to collect and collect comparison data from the size comparison unit. An adaptive equalization method of an adaptive equalization apparatus including a digital control unit that finds an optimal equalizer control code based on the obtained comparison data and provides it to the first equalization filter,
Setting the equalizer monitoring code K as 0 (zero), the reference signal control code S as 0 (zero), the maximum peak as 0 (zero), and the optimum code as 0 (zero);
Inputting a K-th equalizer monitoring code to the second equalization filter;
Generating a reference signal corresponding to the S-th reference signal control code, collecting the results of performing X-time sampling by the size comparison unit, and counting a high number of the collected sampling results;
Determining whether an absolute value of the difference between the counted current counting value and the previous counting value is greater than the maximum peak;
If the absolute value of the difference between the current counting value and the previous counting value is greater than the maximum peak, the maximum peak is replaced with an absolute value of the difference between the current counting value and the previous counting value, and the optimal code is monitored by the current equalizer. Replacing the code with a value, and replacing the previous counting value with the current counting value;
Determining whether the value of the reference signal control code is a maximum value of a preset reference signal control code;
If the value of the reference signal control code is the maximum value of the reference signal control code, determining whether the value of the equalizer monitoring code is the maximum value of the preset equalizer monitoring code; And
And if the value of the equalizer monitoring code is the maximum value of the preset equalizer monitoring code, reflecting the optimal code as an optimal equalizer control code to the first equalization filter; and adaptive equalization comprising: Way. The method of claim 1,
If the absolute value of the difference between the current counting value and the previous counting value is not greater than the maximum peak, the previous counting value is replaced with the current counting value without replacing the maximum peak and the optimal code. The method of claim 1,
As a result of the determination in the step of determining whether the value of the reference signal control code is the maximum value of the preset reference signal control code, if the value of the reference signal control code is not the maximum value of the reference signal control code, the reference signal control code Moving to the step of generating a reference signal corresponding to the S-th reference signal control code by adding a value to the S-th reference signal control code, collecting the results of performing X-time sampling in the size comparison unit, and counting the high number of the collected sampling results. Adaptive equalization method, characterized in that. The method of claim 1,
As a result of the determination in the step of determining whether the value of the equalizer monitoring code is the maximum value of the preset equalizer monitoring code, if the value of the equalizer monitoring code is not the maximum value of the preset equalizer monitoring code, the equalizer monitoring And inputting a K-th equalizer monitoring code to the second equalization filter by +1 to a value of the code.

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