Patent Abstract:
Disclosed is an antenna controller of a digital television receiver and a controlling method thereof including an antenna receiving channel signals of digital television broadcasting and having a directionality dependent on a control signal, a signal processing part tuning a wanted channel signal from the channel signals and processing the tuned channel signal as a wanted form, a detection part detecting state signals of the channel signal outputted from the signal processing part, a memory, when every new state signal is detected, storing the detected new state signal sorted with previously-detected state signals, a control part producing the control signal corresponding to an optimal direction of the antenna by comparing the new state signal to the previous state signals, and an interface part providing the antenna with the control signal, thereby enabling to increase the integration of the receiver.

Full Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a digital television receiver and method of controlling an antenna of the same, and more particularly, to an antenna controller of a digital television receiver and a controlling method thereof. 
   2. Background of the Related Art 
   VSD (Vestigial Side Band) has been chosen as a standard form for transmitting a terrestrial microwave channel in digital television broadcasting. Thus, concepts and ideas have been made to propose the early-stage antennas for a VSB receiver, and ATSC prepares the standardization of the VSB antennas. Yet, no antenna applied to a digital television receiver has been introduced in public, and further has been commercialized. 
   Generally, antennas able to be used for digital television receivers are mainly divided into two categories. 
   First, there is a general outdoor antenna having a benefit of high receive performance but having defects such as large size and installment inconvenience. 
   Second, there is an indoor antennal having benefits of small size and installment convenience but defects such that a viewer has to adjust a direction of the antenna by monitoring a screen in direct when a receive sensitivity is reduced. 
   Besides, a plurality of multi-paths and frequency obstacles have a chance to exist in the terrestrial channels in the digital television broadcasting. Therefore, receive characteristics of an antenna of a digital television receiver may have a great influence on the entire characteristics of the digital television receiver. Other antennas and their problems depending on their environments are described as follows by referring to  FIG. 1  to  FIG. 3 . 
     FIG. 1  to  FIG. 3  show diagrams of a no-directional antenna, a directional antenna, and a smart antenna, respectively. 
   First, a television receiver using a non-directional antenna in  FIG. 1  enables to receive the major signal from all directions only through the channels where intensity of the main signal is strong while signals in multi-paths are weak. Yet, the television receiver in  FIG. 1  fails to easily receive the wanted channel in the channels where the main signal is weak and the signals in the multi-paths are strong through indoor antennas, downtown-building-area antennas and the like, thereby reducing the performance of the digital television receiver. 
   Second, a direction antenna in  FIG. 2  may be used in order to overcome the defects of the non-directional antenna. Yet, the main signal may be blocked by the moving obstacles against radio waves under the circumstance that states of the channels vary severely. In this case, it is difficult for the antenna to receive the main signal from other directions, whereby the performance of the digital television receiver is reduced as well. As mentioned in the foregoing explanation, the non-directional antenna has a trade-off relation with the directional antenna. 
   Third, a smart antenna in  FIG. 3  may be considered as a solution so as to solve the problems of the non-directional and directional antennas. The above defects/problems may be settled by making use of the smart antenna on the assumption of the existence of a control system. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention is directed to an antenna for a digital television receiver, controller and controlling method of the same that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
   An object of the present invention is to provide an antenna for a digital television receiver, controller and controlling method of the same enabling to increase integration of the digital television receiver by constructing the antenna with a single chip. 
   Another object of the present invention is to provide an antenna for a digital television receiver, controller and controlling method of the same enabling to construct the antenna with a simple hardware so as to reduce a product cost. 
   A further object of the present invention is to provide an antenna for a digital television receiver, controller and controlling method of the same having a prompt judgment and high reliance. 
   Another further object of the present invention is to provide an antenna for a digital television receiver, controller and controlling method of the same compatible with other digital television receivers by being operated independently from the digital television receiver. 
   In order to attain the objectives, an antenna controller of a digital television receiver according to the present invention is constructed with digital control parts and operated separately and independently from the digital television receiver and extracts channel information from a receive chip only without using additional hardware. Moreover, an antenna controller of a digital television receiver according to the present invention attains channel information for controlling an antenna from an automatic gain controller as an initial step in a demodulation part of a digital television receiver, a data segment synchronizer as a middle step, an equalizer as a terminal step, and an SNR calculator step by step. Further, the antenna is controlled to maintain an optimal state using the extracted information. Accordingly, an apparatus and method according to the present invention enables to optimize the antenna of the digital television receiver at a severely-varying channel environment of the terrestrial microwave all the time and further improve the performance of the digital television receiver. 
   Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
   To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a digital television receiver includes an antenna receiving channel signals of digital television broadcasting and having a directionality dependent on a control signal, a signal processing part tuning a wanted channel signal from the channel signals and processing the tuned channel signal as a wanted form, a detection part detecting state signals of the channel signal outputted from the signal processing part, a memory, when every new state signal is detected, storing the detected new state signal sorted with previously-detected state signals, a control part producing the control signal corresponding to an optimal direction of the antenna by comparing the new state signal to the previous state signals, and an interface part providing the antenna with the control signal. 
   In another aspect of the present invention of a digital television receiver having an antenna of which direction is adjustable, an antenna controller, and a memory, a method of controlling an antenna of a digital television receiver includes a step (a) of storing an effective power of the channel signal received through the antenna in the memory by rotating the direction of the antenna and selecting an antenna pattern when a maximum signal power is detected, a step (b) of aligning the stored antenna patterns in order of sizes of the stored signal powers, and a step (c) of detecting states of the channel signal, a power of the channel signal, a maximum ghost power, and a signal vs. noise ratio and then changing a pattern of the antenna in accordance with the detected values. 
   It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
       FIG. 1  illustrates a diagrams of a non-directional antenna; 
       FIG. 2  illustrates a diagram of a directional antenna; 
       FIG. 3  illustrates a diagram of a smart antenna; 
       FIG. 4  illustrates a construction diagram of a digital television receiver having an antenna and a controller of the antenna according to the present invention; 
       FIG. 5  illustrates a block diagram showing parts in  FIG. 4  in detail; 
       FIG. 6  illustrates a block diagram of an interface part for connecting an antenna to an antenna controller; 
       FIG. 7  illustrates a block diagram for explaining a method of controlling an automatic gain using an automatic gain control signal delayed by a digital television receiver; 
       FIG. 8  illustrates a block diagram for explaining a method of controlling gains of high and intermediate frequency signals directly in a VSB receive chip; 
       FIG. 9  illustrates a block diagram for explaining a signal power detection controller; 
       FIG. 10  illustrates a block diagram of a ghost signal power detector in detail; 
       FIG. 11  illustrates an information graph of a ghost signal detected by a ghost power detector; 
       FIG. 12  illustrates a constructional block diagram of a signal vs. noise ratio calculator; 
       FIG. 13  illustrates a block diagram of parts of an antenna controller in detail; 
       FIG. 14  illustrates a diagram of signals sent/received between elements of the antenna controller reciprocally; 
       FIG. 15  illustrates an entire control flowchart of the antenna controller according to the present invention; 
       FIG. 16A  illustrates a detailed flowchart of a scanning procedure in  FIG. 15 ; 
       FIG. 16B  illustrates a flowchart for searching a maximum power value of the tuned channel signal in the scanning procedure in  FIG. 16A ; 
       FIG. 16C  illustrates a flowchart of a count procedure considering all antenna conditions in order to seek a maximum signal power value during the scanning procedure in  FIG. 16A ; 
       FIG. 17  illustrates a flowchart of showing an aligning process of data stored in a memory; 
       FIG. 18  illustrates a flowchart of a tracking processing of an antenna controller according to the present invention; 
       FIG. 19  illustrates a flowchart of a sub-processing of a signal power tracking process; 
       FIG. 20  illustrates a flowchart of showing a sub-processing of a maximum ghost power tracking process according to the present invention; and 
       FIG. 21  illustrates a flowchart of a sub-processing of a signal vs. noise ratio tracking process. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
     FIG. 4  illustrates a construction diagram of a digital television receiver having an antenna and a controller of the antenna according to the present invention.  FIG. 4  is mainly constructed with a channel signal processing part  108  of a digital television receiver and an antenna controller  109 . 
   Referring to  FIG. 4 , the channel signal processing part  108  of the digital television receiver is constructed with a tuner  101  tuning a wanted channel signal among channel signals received through an antenna  100 (a smart antenna is used in this embodiment of the present invention but various other antennas may be realized in this embodiment) present of the digital television receiver, an intermediate frequency automatic gain controlling part  102  adjusting an intermediate frequency IF gain of the channel signal tuned by the tuner  101  automatically, and a VSB receive chip  103  taking a VSB (vestigial side band) signal from a channel signal of the intermediate frequency automatic gain controlling part  102 . 
   The antenna controller  109  is constructed with a detector  104  attaining state signals such as a channel signal power from the channel signal taken by the VSB receive chip  103  of the channel signal processing part  108 , a ghost signal power, a ratio between a signal and a noise and the like, a memory  105  storing the state signals therein and updating storage values with newly-detected state signals, a direction controller  106  attaining a control signal to control a direction of the antenna  100  by comparing the state signals of the detector  104  and the previous state signals stored in the memory  105 , and an interface part  107  connected between the antenna  100  and the tuner  101  and controlling the direction of the antenna  100  in accordance with the control signal. 
     FIG. 5  illustrates a block diagram showing parts in  FIG. 4  in detail. 
   Referring to  FIG. 5 , the VSB receive chip  103  in  FIG. 4  is constructed with an automatic gain control part  103 - 1  controlling a gain of an output signal of the interme 4 diate frequency automatic gain control part  102  automatically, a timing and carrier restoration part  103 - 2  restoring the timing and carrier loss on an output of the automatic gain control part  103 - 1 , an equalizer  103 - 3  equalizing an output of the timing and carrier restoration part  103 - 2 , a phase tracker  103 - 4  tracking down a phase of an output signal of the equalizer  103 - 3 , and a forward error corrector  103 - 5  outputting a final VSB signal by correcting a forward error on an output signal of the phase tracker  103 - 4 . 
   The detector  104  is constructed with a signal power detector  104 - 1  detecting a power of the tuned channel signal using an automatic gain control signal from the automatic gain controller  103 - 1  of the VSB receive chip  103 , a ghost power detector  104 - 2  detecting a power of a ghost signal using a signal from the equalizer  103 - 3  and/or an output signal of the timing and carrier restoration part  103 - 2  of the VSB receive chip  103 , and a signal vs. noise ratio (SNR) calculator  104 - 3  calculating a ratio between a signal and a noise using an output of the phase tracker  103 - 4  of the VSB receive chip  103 . 
   The direction controller  106  in  FIG. 4  is constructed with a signal power tracker  106 - 1  tracking down a power of the tuned channel signal using an output signal of the signal power detector  104 - 1 , a ghost power tracker  106 - 2  tracking down a power of the ghost signal using an output signal of the ghost power detector  104 - 2 , a signal vs. noise ratio (SNR) tracker  106 - 3  tracking down a ratio between a signal and a noise using an output of the signal vs. noise ratio calculator  104 - 3  of the detector  104 , a tracking processor  106 - 4  tracking down state signals of the tuned channel signal using output signals of the trackers  106 - 1  to  106 - 3  in a presently-selected antenna pattern and then changing the antenna pattern in order stored in the memory  105  if the tracked state signals fail to maintain effective value sizes, a scan processor  106 - 5  attaining an effective signal power and antenna pattern by varying a direction of the antenna  100  using a state signal of the tracking processor  106 - 4  and then storing the power and pattern values in the memory  105 , and a sort processor  106 - 6  aligning the stored antenna pattern values in order of the signal power values. Besides, the direction controller  106  makes the scan processor  106 - 5  carry out the scanning again if it is judged that there is no antenna pattern having an effective size in the memory  105  by the operation of the tracking processor  106 - 4 . 
   Operations of the respective major elements in  FIG. 4  and  FIG. 5  are described as follows. The antenna  100  responds to a mechanical or electrical control signal from outside so as to adjust its beam width, gain, frequency characteristic and the like and further construct an optimal pattern for receiving a wanted channel. 
   The interface part  107 , as shown in  FIG. 6 , connects the antenna  100  to the antenna controller  109 . 
   A procedure of detecting a signal power of the tuned channel signal is explained as follows. 
     FIG. 7  illustrates a block diagram for explaining a system of controlling an automatic gain using an automatic gain control signal delayed by a digital television receiver, and  FIG. 8  illustrates a block diagram for explaining a system of controlling gains of high and intermediate frequency signals directly in a VSB receive chip  103 . The automatic gain control (AGC) system controls a gain of an intermediate frequency signal through a electric charge pump &amp; lag filter  110  from the VSB receive chip  103  and a high frequency signal gain automatically using an automatic gain control signal delayed in the intermediate frequency automatic gain control part  102 . In accordance with an automatic gain control system, the intermediate frequency signal and high frequency signal gain are controlled automatically by the VSB receive chip  103 . Besides, the automatic gain control part  103 - 1  in  FIG. 5  constructs a loop controlling one automatic gain control amplifier and the signal power detector  104 - 1  in  FIG. 5  detects the signal power of the tuned channel signal from a storage part (ex. Integrator) storing a gain error included in the loop. A signal power detection controller (included in the signal power detector  104 - 1  in  FIG. 5 )  111  in  FIG. 9  detecting a signal power ready signal and a signal power information from automatic gain control information outputted from the VSB receive chip  103  and then outputs the signal power ready signal and signal power information to the direction controller  106  of the antenna  100 . 
   The ghost signal power detector  104 - 2  in  FIG. 5 , as shown in  FIG. 10 , is constructed with a data segment synchronization correlative  112  calculating a correlation value between an I channel signal received from the VSB receive chip  103  and a previously-set synchronization signal value (cf. a synchronization value “1001” is inserted into each data segment in a VSB transmission system), a segment integrator  113  accumulating output values of the data segment synchronization correlative  112  in 832 delayers, a slicer  114  providing an increased count value when the accumulated correlation value reaches a predetermined size, a confidence counter  115  increasing the count number according to the increased count value, and a maximum ghost power detection controller  116  transferring a ghost power ready signal and a standardization value resulted from standardizing a maximum ghost power into a power of a receive signal to the direction controller  106  of the antenna in  FIG. 4  when the value of the confidence counter  115  reaches a reference value. 
     FIG. 11  illustrates an information graph of a ghost signal detected by the ghost power detector  104 - 2 . Namely, the correlation value accumulated in the segment integrator  113  in  FIG. 10  is shown in  FIG. 11  where a tap having a maximum correlation value is a value accumulated by a main signal and another correlation value corresponding to a next size is a value accumulated by a ghost signal generated from the multi-paths. 
   The signal vs. noise ratio calculator  104 - 3  is explained in the following description in detail. 
     FIG. 12  illustrates a constructional block diagram of a signal vs. noise ratio calculator, in which a signal vs. noise ratio (SNR) is calculated using MSE (means square error). The signal vs. noise ratio calculator  104 - 3  in  FIG. 12  may include a subtractor  117  subtracting a demodulated signal constellation (a received field synchronization signal or I-channel data) from a decision signal constellation (a train sequencer or decision signal arrangement), a squarer  118  squaring an output of the subtractor  117 , an accumulator  119  accumulating outputs of the squarer  118  therein, a latch  120  delaying an output of the accumulator  119 , and a divider  121  dividing an output of the latch  120  into a window size m of the segment integrator  113  of the ghost signal power detector  104 - 2 . An algorithm of the signal vs. noise ratio according to the construction in  FIG. 12  follows. First, a signal vs. noise ratio (SNR) is represented by the following formula (1).
   SNR= 10 log( Ps/Pn )  (1), 
where Ps is a signal power (=1) and Pn is a noise power (Pn|mse).
 
   And, an algorithm of calculating a signal vs. noise ratio by a mean square error is represented by the following formula (2).
 
 Pn|mse=sigma ( k  is 1 to  n )( mse/m )  (2)
 
   In the formula (2), ‘mse’ may be represented by the following formula (3).
 
 Mse =( D   — 1 −R   — 1) 2   (3)
 
   In the formula (1) to formula (3), ‘R — 1’ and ‘D — 1’ are a demodulated signal constellation (received constellation) and a decided signal constellation (decision constellation), respectively, and ‘m’ designates a window size of the integrator  113 . 
   The direction controller  106  and memory  105  in  FIG. 4  and  FIG. 5  are explained in the following description. 
     FIG. 13  illustrates a block diagram of parts of an antenna controller in detail. Referring to  FIG. 13 , the direction controller  106  of the antenna controller  109  is constructed with the tracking processor  106 - 4 , scan processor  106 - 5 , sort processor  106 - 6 , and general registers. The general registers shown in  FIG. 13  include a pointer register representing a memory address, a direction register Dir_reg. always storing the present antenna state value, an angle register storing temporarily a state value of the antenna, and a power register storing a power value of a received signal temporarily. As shown in  FIG. 13 , the memory  105  stores a state value (or pattern value) of the antenna  100  and a corresponding power value of the received signal therein and aligns the stored power values in order of their sizes so as restore them therein. 
     FIG. 14  illustrates a diagram of signals sent/received between elements of the antenna controller reciprocally. 
     FIG. 15  illustrates an entire control flowchart of the antenna controller according to the present invention, which is mainly divided into a scan process of detecting and storing a channel signal, a sort process, and a tracking process. 
   In the scan process, the antenna controller detects whether a channel signal exists at an initialized state. If the channel signal is detected an effective power of the channel signal, which is being detected, is stored in the memory  105  by rotating the direction of the antenna  100  at 360° and an antenna pattern is selected when a maximum signal power is detected. 
   In the sort process, the antenna controller aligns the stored antenna patterns in order of the stored signal powers. 
   In the tracking process, the antenna controller detects states, i.e. a power of the channel signal, a maximum ghost power, and a signal vs. noise ratio, of the tuned channel signal in the presently-selected antenna pattern and then judges whether the detected values maintain effective sizes. In accordance with the result of the judgment, the antenna pattern is changed in order of the entire stored/aligned antenna patterns if the change of the antenna pattern is necessary. When there is no effective one in the entire antenna patterns stored in the memory, the antenna controller carries out the scan process again in order to get the effective signal power and antenna pattern. The above-mentioned processes observe the digital television receiver on real-time for the moving obstacles against waves such as people and the like, maintains the optimal state of the antenna according to the observation result, and further optimizes the performance of the digital television receiver. 
     FIG. 16A  illustrates a detailed flowchart of a scanning procedure in  FIG. 15 . Referring to  FIG. 16A , the antenna controller checks whether the detection of a power of the received channel signal is ready after initialization (check signal power ready ?). If the detection is ready (signal PW ready=‘1’), a power value of the detected channel signal is taken (Latch power_d). It is then checked whether the power value of the detected channel signal is effective (check PW_thd). If it is verified that the power value is effective (PW_phd&lt;PW_reg), the antenna controller starts a maximum search process of finding a maximum power value of the channel signal and a corresponding antenna pattern (Max_en). Subsequently, the power value of the channel signal stored temporarily in the angle and power registers and a corresponding antenna state are stored in the memory address designated by the pointer register (memo_r_w), and a value of the pointer register is incremented by ‘1’ (Pointer++). Meanwhile, the antenna controller carries out a maximum value search process and a count process (proc.:MAX._SEAR. &amp; COUNT). During carrying out the foregoing search process and count process, the antenna controller ascertains whether all the patterns of the possible antenna are tried. If all the patterns of the possible antenna fail to be tried, the respective registers of the direction controller  106  and the direction register value are incremented by ‘1’ respectively (Ang._reg++; Dir._reg++). If all the patterns are tried, a pattern value (state value) of the antenna, of which maximum signal power is detected by the direction register in the memory  105 , is set. Then, the sort processing procedure (or alignment processing procedure) is carried out through a sort processor (Sort_strob=1, Proc.:SORT), and it is verified whether the sort processing procedure is finished (check sort_ack=1). Subsequently, if the sort processing procedure is finished (Sort_ack=1), a tracking processing procedure is carried out through a tracking processor  106 - 4  (track_strob=1, Proc.:TRACK) and it is checked whether the tracking processing procedure is finished. If the tracking process is finished (track_ack=1), it goes back to the initialization process. 
     FIG. 16B  illustrates a flowchart for searching a maximum power value of the tuned channel signal in the scanning procedure in  FIG. 16A . First, the antenna controller sets a maximum power value of the channel signal as ‘0’ (PW_MAX=0) and verifies whether the maximum value enabling signal is ‘1’ (MAX_EN=1). When the maximum value enabling signal is ‘1’ (MAX_EN=1), the value stored in the respective registers and power register is taken as the maximum signal power value provided that the present maximum signal power value is less than the value stored in the power register of the direction controller  106 . And, a process of verifying the next maximum enabling signal proceeds. 
     FIG. 16C  illustrates a flowchart of a count procedure considering all antenna conditions in order to seek a maximum signal power value during the scanning procedure in  FIG. 16A . Referring to  FIG. 16C , a count value is set as zero (count=0). Then, it is ascertained that a counter reset signal is set as ‘1’. If the counter reset signal and the pointer value are not ‘1’ and ‘0’ respectively, the counter value is incremented by ‘1’. Then, it goes back to a process of ascertaining whether the counter reset signal is ‘1’. On the other hand, if the counter reset signal is ‘1’, the signal power ready signal value is not ‘1’ or the pointer value is ‘0’, the controller goes back to the process of setting the counter value as ‘0’. 
     FIG. 17  illustrates a flowchart of showing an aligning process of data stored in a memory. 
   Referring to  FIG. 17 , the antenna controller  109  inputs a count of data stored in the memory  105  to a Sr_lim variable (Sr_lim&lt;=pointer−1). Then, the scan process in  FIG. 16A  to  FIG. 16C  is checked (check sort_strob). If the scan process is finished (Sort strob=‘1’), data in the memory are read into the angle and power registers if the direction controller  106  (Ang_reg, PW_reg&lt;=memo_in). Successively, a Sr_cnt_k value is inputted to an Sr_cnt value and an Sr_max variable respectively (Sr_max&lt;=Sr_cnt_k), and the angle and power register values are inputted to an Sr_max_reg. variable in which a maximum value of the stored data is stored (Sr_max_reg.&lt;=Ang._reg., PW_reg.). Subsequently, an Sr_cnt — 1 value is inputted to an Addr variable generating the memory address (Addr&lt;=Sr_cnt — 1), and an Sr_max_reg. variable value storing the maximum value in the stored data is compared to a power register value (check Sr_maxreg.&lt;PW_reg.). Next, the Sr_cnt — 1 value is inputted to the Sr_max variable (Sr_max&lt;=Sr_cnt — 1), and the angle and power register value is inputted to the Sr_max_reg. variable storing the maximum value in the stored data (Sr_max_reg.&lt;=Ang._reg., PW_reg.). After the Sr_cnt — 1 value is incremented by ‘1’ (Sr_cnt — 1++), the memory data corresponding to the Sr_cnt — 1 value is read by the angle and power registers (Ang._reg., PW_reg.&lt;=memo_in(Sr_cnt_ 1 )). After the Sr_cnt — 1 value and the Sr_lim value are compared to each other (Sr_cnt — 1=Sr_lim), the memory data corresponding to the Sr_cnt_k value is read by the angle and power registers (Ang._reg, PW_reg.&lt;=memo_in(Sr_cnt_k)). Then, the antenna controller  109  stores the Sr_max_reg. value in the memory  105  corresponding to an address of the Sr_cnt_k value (memo_out(Sr_cnt_k)) and makes a state of the memory  105  enable to store a value (memo_r_w=1). After the Sr_cnt_k value is incremented by ‘1’ (Sr_cnt_k++), it is checked whether the alignment is finished by comparing the Sr_cnt_k value to the Sr_lim — 1 value (check Sr_cnt_k=Sr_lim — 1). After the angle and power register values are stored in the memory having an address corresponding to the Sr_max value (memo_out(sr_max)&lt;=Ang._reg., PW_reg.), a storage of the memory  105  is made possible (memo_r_w=1) and the scan processor  106 - 5  is informed of the completion of the sort process (sort_ack=1). 
     FIG. 18  illustrates a flowchart of a tracking processing of an antenna controller according to the present invention. First, the antenna controller  109  sets a tr_cnt variable as ‘1’ through the tracking processor  106 - 4  (tr_cnt&lt;=‘0001’ and then checks that the sort processing process is finished (check track_strob=1). Then, execution of a sub-processing process included in the tracking processing process is enables (Enable=1). Subsequently, it is checked whether the calculated signal vs. noise ratio is effective (SNR condition), and subsequently, the effectiveness of the detected maximum ghost value and the detected signal power value is verified (GHOST power condition, Signal power condition). Subsequently, the tracking processor  106 - 4  of the antenna processor  109  checks that all the data stored in the memory  105  are used (tr_cnt=pointer), and increases the tr_cnt value by ‘1’ (tr_cnt++). Successively, a value of the memory address corresponding to the tr_cnt is inputted to the direction register of the direction controller  106  (dir_reg.&lt;memo_in(tr_cnt)), and the scan processor  106 - 5  is informed of a completion of the tracking processing process (track_ack=1). 
     FIG. 19  illustrates a flowchart of a sub-processing of a signal power tracking process. 
   After the confidence counter is set as a value of ‘0’ (confidence=0), a signal power condition value directing whether the detected signal power is effective is set as ‘1’ (signal PW condition=1). Then, it is checked whether the execution of the sub processing process of the signal power tracking process is enabled (enable=1), and it is checked whether the signal power tracker  106 - 1  is ready for detecting a signal power (signal PW ready=1). Then, the confidence is checked by comparing a confidence value to an unlocking threshold value Unlock_thd (confidence=unlock_thd ?). Moreover, the confidence is checked by comparing the confidence value to a locking threshold value Lock_thd (confidence=lock_thd ?), and the effectiveness of the detected signal power is checked (signal PW&lt;TOV). Then, the confidence value is decremented by ‘1’ (confidence−−) or incremented by ‘1’ (confidence++) in accordance with whether the signal power is effective. Finally, when the confidence value is equal to the unlocking threshold value (confidence=unlock_thd), a signal power state value representing whether the detected signal power value is effective is set as ‘0’ (signal PW condition=0). 
     FIG. 20  illustrates a flowchart of showing a sub-processing of a maximum ghost power tracking process according to the present invention. 
   First, the ghost power tracker  106 - 2  sets a ghost state value representing whether the detected ghost power is effective as ‘1’ after setting a timer counter as a ‘0’ value (ghost PW condition=1). And, it is checked whether the execution of the sub processing is enabled (enable=1), and it is checked whether the timer counter reaches a trial limit value try_lim (counter=try_lim). After it is checked whether the maximum ghost power detector  116  is ready for detecting a ghost power (ghost PW ready=1), it is checked whether the maximum ghost power maintains a predetermined size compared to a main signal, i.e. whether the maximum ghost power is effective (main signal&lt;max ghost*2). For instance, if the maximum ghost power maintains a predetermined size against the main signal, the ghost state value representing whether the detected ghost power is effective is set as ‘0’ (ghost PW condition=0). 
     FIG. 21  illustrates a flowchart of a sub-processing of a signal vs. noise ratio tracking process. 
   After the confidence counter value is set as ‘0’ (counter=0), a signal vs. noise ratio state value representing whether the calculated signal vs. noise ratio is effective (signal PW condition=1). It is checked whether the sub processing process is enabled (enable=1) and whether the SNR calculator  104 - 3  is ready for detecting SNR (SNR ready=1). Moreover, it is checked whether the detected SNR is effective (SNR&gt;=THD) and the confidence is checked by comparing the counter value to the unlocking threshold value (counter=unlock_thd). If there is no confidence, it goes back to the initial process. If the counter value counter is not equal to the trial limit value try_lim, the counter value is incremented by ‘1’ (counter++). Then, it goes back to the step of checking whether the sub processing process is enabled. On the other hand, if the counter value is equal to the trial limit value, the ghost state value representing whether the detected SNR is effective is set as ‘0’ (SNR condition=0). Then, it goes back to the initial step of the sub processing process. Otherwise, if it is not ready for detecting the SNR, it goes back to the step of checking whether the sub processing process is enabled. 
   The present invention takes a VSB receiver as an example and further enables to be applied to other wire communication fields such as an OFDM receiver and the like without limiting the scope thereof. 
   Accordingly, an antenna controller according to the present invention enables to simplify a hardware thereof, and further reduce the product cost by attaining channel information through a receive chip only without using additional hardware in order to observe a channel. 
   And, the present invention attains channel information for controlling an antenna from an automatic gain controller as an initial step in a demodulation part of a digital television receiver, a data segment synchronizer as a middle step, an equalizer as a terminal step, and an SNR calculator step by step, thereby enabling to control an antenna of a digital television receiver with prompt judgment and high confidence. 
   Moreover, the present invention enables to operate independently from a digital television receiver, thereby having compatibility with other digital television receivers. 
   Further, the present invention of which control parts are constructed with a digital system so as to comprise a single chip and further increase integration of a device. 
   The forgoing embodiments are merely exemplary and are not to be construed as limiting the present invention. The present teachings can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art.

Technology Classification (CPC): 7