This application claims priority from Korean Patent Application No. 10-2014-0130536, filed on Sep. 29, 2014, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.
1. Field
Methods, devices, apparatuses, and articles of manufacture consistent with the present disclosure relate to an error detector and a method for detecting an error of an oscillator, and more particularly, to an error detector and a method for detecting an error of an oscillator capable of detecting a defect of the oscillator used on a board using a broadcast signal.
2. Description of the Related Art
Recently, an electronic device includes boards configured of various circuits. For example, there is a board embedded in a display device such as a television (TV). An oscillator generating a clock signal is present on the board. In a digital circuit, synchronous processing for processing a signal so as to be synchronized with the clock signal uses the oscillator. A typical kind of oscillator includes a voltage-controlled oscillator (VCO) and a crystal oscillator.
It is advantageous for the oscillator to accurately generate a signal having a desired frequency in order to ensure an accurate operation of an electronic circuit. Thus, it is advantageous to detect whether or not a defect is generated in the oscillator, because when a defect is generated in the oscillator, a phenomenon that a screen of the display device is distorted, or the like, is generated.
In order to detect a defect, an output of the oscillator has been measured using a scope, a frequency counter, and a spectrum analyzer, or the oscillator has been used without detecting the defect of the oscillator under the assumption that the defect will not cause a problem during operation.
Exemplary embodiments address the above disadvantages and other disadvantages not described above. However, the exemplary embodiments not required to overcome the disadvantages described above, and an exemplary embodiment may not overcome any of the disadvantages described above.
It is an aspect to provide an error detector and a method for detecting an error of an oscillator capable of detecting a defect of the oscillator simultaneously with decoding a broadcast signal applied to a board using the broadcast signal without using a scope, a frequency counter, and a spectrum analyzer.
According to an aspect of an exemplary embodiment, there is provided an error detector comprising a receiver that is configured to receive an oscillation signal of an oscillator and a reference signal; and a controller that is configured to change the oscillation signal within a frequency range so as to correspond to the reference signal and to decide whether an error is generated in the oscillator based on the changed oscillation signal.
The controller may change at least one of a phase and a frequency of the received oscillation signal within the frequency range so as to correspond to at least one of a phase and a frequency of the reference signal.
The controller may stop the change of the oscillation signal after a threshold time elapses.
The controller may decide that the oscillator is normally operated when a color signal component value extracted from the reference signal is a threshold value.
The controller may generate a control command for displaying a corresponding graphical user interface (GUI) in a case in which the error is generated in the oscillator.
The frequency range may be one frequency range selected among a plurality of frequency ranges according to a user input.
The controller may change the oscillation signal of the oscillator in a sequence from a wide frequency range to a narrow frequency range within the selected frequency range so as to correspond to the reference signal.
The reference signal may be a color sub-carrier signal of a national television system committee (NTSC) signal or a phase alternation by line (PAL) signal.
The error detector may further comprise a level detector that is configured to detect an output level of the received oscillation signal, wherein the controller decides that the error is generated in the oscillator in a case in which the output level detected by the level detector is less than a threshold level, and decides whether the error is generated in the oscillator using the frequency range in a case in which the output level detected by the level detector is greater than or equal to the threshold level.
The error detector may further comprise a selector that is configured to select one of a plurality of oscillation signals of a plurality of oscillators, wherein the controller controls the receiver to receive one signal selected among the plurality of oscillator signals through the selector.
According to another aspect of an exemplary embodiment, there is provided a method for detecting an error of an oscillator, the method comprising receiving an oscillation signal of the oscillator and a reference signal; changing the oscillation signal within a frequency range so as to correspond to the reference signal; and deciding whether the error is generated in the oscillator based on the changed oscillation signal.
In the changing, at least one of a phase and a frequency of the received oscillation signal may be changed within the frequency range so as to correspond to at least one of a phase and a frequency of the reference signal.
The method may further comprise stopping the change of the oscillation signal after a threshold time elapses.
In the deciding, it may be decided that the oscillator is normally operated when a color signal component value extracted from the reference signal is a threshold value.
The method may further comprise generating a control command for displaying a corresponding GUI in a case in which the error is determined to be present in the oscillator.
The frequency range may be one frequency range selected among a plurality of frequency ranges according to a user input.
In the changing, the oscillation signal of the oscillator may be changed in a sequence from a wide frequency range to a narrow frequency range within the selected frequency range so as to correspond to the reference signal.
The reference signal may be a color sub-carrier signal of a national television system committee (NTSC) signal or a phase alternation by line (PAL) signal.
The method may further comprise detecting an output level of the received oscillation signal, wherein in the deciding, it is decided that the error is generated in the oscillator in a case in which the detected output level is less than a threshold level, and it is decided whether the error is generated in the oscillator using the frequency range in a case in which the detected output level is greater than or equal to the threshold level.
The method may further comprise selecting one of a plurality of oscillation signals of a plurality of oscillators, wherein in the receiving, one signal selected among the plurality of oscillator signals is received.
The error may be a defect generated in the oscillator.
According to another aspect of an exemplary embodiment, there is provided a method for detecting a defect in an oscillator, the method comprising receiving an oscillation signal from the oscillator and a reference signal; using a phase locked loop (PLL) to control the oscillation signal to try to lock the oscillation signal to the reference signal in a frequency range; and detecting a defect in the oscillator based on whether lock occurs in the frequency range.
The above and/or other aspects will be more apparent by describing certain exemplary embodiments with reference to the accompanying drawings, in which:
Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings.
The receiver 110 receives an oscillation signal of an oscillator and a reference signal. For example, the oscillation signal may be a clock signal generated in the oscillator. The reference signal may be a broadcast signal. As examples of a format of the broadcast signal, there are a national television system committee (NTSC) signal, and a phase alternation by line (PAL) signal that is mainly used in Europe. This will be described below in detail. The receiver 110 receives color sub-carrier signals of these broadcast signals and transfers the color sub-carrier signals to the controller 120.
The controller 120 controls overall components and operations of the error detector 100. Particularly, the controller 120 changes the oscillation signal of the oscillator received in the receiver 110 within a frequency range so as to correspond to the reference signal. The frequency range may be preset. In addition, the controller 120 decides whether or not an error is present in the oscillator based on the changed oscillation signal. That is, the controller 120 decides whether or not a defect is present in the oscillator based on the changed oscillation signal.
In detail, the controller 120 changes at least one of a phase and a frequency of the oscillation signal within the frequency range to track the reference signal so that at least one of the phase and the frequency of the oscillation signal corresponds to at least one of a phase and a frequency of the reference signal. In the case in which the phase and the frequency of the oscillation signal are changed within the frequency range to track the reference signal so that the phase and the frequency of the oscillation signal are the same as those of the reference signal, it is called that LOCK is made. To the contrary, in the case in which the reference signal may not be tracked so that the phase and the frequency of the oscillation signal are the same as those of the reference signal even though the phase and the frequency of the oscillation signal are changed within the frequency range, it is called that UNLOCK is made. The controller 120 may implement the tracking of the reference signal by the change of the oscillation signal through a digital phase locking loop (PLL) such as a burst lock PLL.
The controller 120 stops the change of the oscillation signal and extracts a color component value of the reference signal, when a threshold time elapses. The threshold time may be preset. In addition, the controller 120 decides whether or not the oscillator is normally operated based on the extracted color component value. The controller 120 changes the phase and the frequency of the oscillation signal using a feedback circuit in order to track the reference signal. Therefore, in order to decide whether a state is a state in which the LOCK is made by success of the tracking or a state is an UNLOCK state in which the tracking may not succeed even through continuous feedback, the controller 120 needs to stop the feedback circuit and analyze a component of the reference signal when the feedback circuit is stopped. However, the change of the oscillation signal may be very rapidly performed. For example, in the case of the NTSC signal, frequency tracking is completed in a time of about 1 ms. Therefore, the controller 120 sets a sufficient time for at least one of the phase and the frequency of the oscillation signal to correspond to at least one of the phase and the frequency of the reference signal, and stops the feedback circuit and extracts a parameter for deciding whether or not the error is present in the oscillator when the time elapses.
The controller 120 may generate a control command for displaying a corresponding graphical user interface (GUI) when it is decided that an error is present in the oscillator signal. The GUI may be a notification message notifying that an error is generated in a specific oscillator. As an example, in the case in which the error detector 100 is implemented in a device having a display, the controller 120 may control the display to display the GUI. As another example, in the case of a remote diagnosis, the controller 120 may also control a communicating circuit to transmit the notification message, or the like, to an external device performing the remote diagnosis.
The controller 120 may set a plurality of frequency ranges and sequentially set the frequency ranges to frequency ranges in which the oscillation signal may be changed in a sequence of wide frequency ranges, thereby deciding whether or not the LOCK is made. The controller 120 may recognize a specification in which the oscillator may be operated without an error by decreasing frequency ranges that may be sequentially changed. For example, when the TV has a specification that a screen output, or the like, is not affected even by a frequency variation up to 100 ppm, the controller 120 may directly set a frequency range to 100 ppm, or sequentially set a plurality of frequency ranges from 200 ppm, which is a wide range, to 150 ppm and 100 ppm, thereby deciding whether or not the LOCK is made. In the case in which the LOCK is made, it is called that SPEC IN of the frequency of the oscillator is made, and in the case in which the UNLOCK is made, it is called that SPEC OUT of the frequency of the oscillator is made.
A user may decide the SPEC IN and/or the SPEC OUT of the frequency of the oscillator using the broadcast signal through the error detector 100 as described above. Since the case in which the SPEC OUT is made corresponds to the case in which the oscillator may not be appropriately operated, the error detector 100 may decide that the error is generated in the oscillator and provide a notification message to the user for notifying the user that an individual oscillator or an entire board needs to be replaced.
The receiver 110 receives the reference signal, and the oscillation signal of the oscillator. In some exemplary embodiments, the reference signal may be a color sub-carrier signal of national television system committee (NTSC) or phase alternation by line (PAL). The NTSC scheme is a broadcast signal transmitting scheme of faithfully transmitting three primary colors (R, G, and B) with respect to large area signals, accurately transmitting a luminance of a color with respect to a medium area signal, and transmitting only a luminance signal with respect to small area signals. In the NTSC scheme, different signals are transmitted depending on areas using the fact that human eyes do not substantially feel a color with respect to a small area. In the NTSC scheme, it is advantageous to have a high performance of a transmission circuit for the purpose of high level band compression. The PAL scheme is a color TV broadcasting scheme developed in Germany. The PAL scheme has a feature that a color change depending on a signal transmission system is less than that of the NTSC scheme and a high level specification is not required in broadcasting equipment. The PAL scheme is a broadcast signal transmission scheme that is mainly used in Europe.
The selector 130 may select one of oscillation signals of a plurality of oscillators. The plurality of oscillators may be present on one board, and the selector 130 may select a specific oscillator of the plurality of oscillators and transfer an oscillation signal to the controller 120. For example, the selector 130 may be implemented through a multiplexer (MUX). The MUX is a device allowing a plurality of signals to be transmitted through one channel. When the MUX is used, a signal that is to be transmitted may be selected. For example, an MUX having eight inputs may select a specific input by three bits of selection command. The selector 130 may detect whether or not an error is present in the specific oscillator on the board on which the plurality of oscillators are present.
The ADC 140 converts an analog signal into a digital signal. According to some exemplary embodiments, the ADC 140 converts the oscillation signal of the oscillator, which is the analog signal received in the receiver 110, into a digital signal. The ADC 140 converts the signal into the digital signal in order for a level detector 150 to be described below to compare the digital signal with an output level. For example, the ADC 140 may be implemented by an analog to digital converter circuit (ADC) and a comparator. The output level may be preset.
The level detector 150 detects an output level of the oscillator. The level detector 150 may detect the output level of the oscillator based on the oscillation signal converted into the digital signal. In addition, the level detector 150 may directly compare the detected output level with a threshold level to decide whether or not the error is generated in the oscillator, instead of transmitting the detected output level to the controller 120. The threshold level may be preset. In a complementary metal oxide semiconductor (CMOS), since the oscillator is not operated in the case in which an output of the oscillator is lower than a threshold level, even though a frequency is accurately output, the oscillator may not perform a function. Therefore, before the error of the oscillator is detected using the frequency, the level detector 150 may primarily detect the output level to screen the oscillator in which the error is generated.
The SRC 160 converts a sampling rate to tune frequencies of the reference signal and the oscillation signal of the oscillator to each other. The SRC is an abbreviation of a sample rate converter. After the frequencies of the reference signal and the oscillation signal coincide with each other through the SRC 160, the controller 120 changes the oscillation signal so that phases of the two signals become the same as each other using a digital PLL. The sampling rate is determined based on the frequencies of the reference signal and the oscillation signal. As an example, in the case in which a frequency of the oscillation signal is 24 MHz, when an NTSC signal having a frequency of 3.58 MHz is the reference signal, the SRC 160 performs sampling approximately eight times. That is, the SRC 160 uses a 8× sampling rate. As another example, when a PAL signal having a frequency of 4.43 MHz is the reference signal, the SRC 160 performs sampling approximately six times. That is, the SRC 160 uses a 6× sampling rate. As described above, the SRC 160 allows the frequencies of the received reference signal and the oscillation signal to coincide with each other and transmits them to the controller 120.
In addition, the error detector 100 may further include a communication circuit, a display, and an interface circuit.
The communication circuit allows communication with an external device to be performed. When it is to be detected whether or not the error is generated in the oscillator through remote diagnosis, the communication circuit transmits and receives data for the remote diagnosis, or the like, to and from the external device. The communication circuit may comprise a wireless or wired communication module. The communication circuit may use high definition multimedia interface (HDMI), low voltage differential signaling (LVDS), local area network (LAN), and the like, as a wired communication scheme. In addition, the communication circuit may use various schemes such as near field communication (NFC), wireless LAN (WLAN), infrared (IR) communication, Zigbee communication, WiFi, Bluetooth, and the like, as a wireless communication scheme. For example, in the case in which the error detector 100 is implemented in a TV or a set top box, the communication circuit may receive a remote diagnosis control command through a path through which the broadcast signal is received.
The display displays a GUI indicating whether or not an error is generated in the oscillator. As an example, in the case in which the error detector 100 is implemented in a TV, the display may be a display panel of the TV. The display may be implemented by various display technologies such as a liquid crystal display (LCD), an organic light-emitting diode (OLED), an E-paper, a plasma display panel (PDP), a vacuum fluorescent display (VFD), a field emission display (FED), an electro luminescence display (ELD), and the like. As another example, in the case in which the error detector 100 is implemented in a set top box, the display may be a board displaying a channel number, or the like. Since the set top box may display an error code, or the like, the user may recognize whether or not the error is generated in the oscillator through a displayed message.
The interface circuit performs a function of receiving a user input. In some exemplary embodiments, the interface circuit may receive a user input setting the plurality of frequency ranges. The interface circuit may be implemented by a remote controller, a touch screen, a keypad, or the like. In addition, the interface circuit may receive the user input in a scheme of displaying a UI on the display. As another example, the interface circuit may receive a selection command for selecting an oscillator of which an error is to be detected among the plurality of oscillators. The interface circuit may transmit the received selection command to the selector 130 through the controller 120 or transmit the received selection command directly to the selector 130.
The controller 120 controls the receiver 110, the selector 130, the ADC 140, the level detector 150, and the SRC 160. The controller 120 controls other components that may be generally included in the error detector 100 although not illustrated or components that may be additionally included in the error detector 100, such as the communication circuit, the display, and the interface circuit. The controller 120 changes the oscillation signal within a frequency range so as to correspond to the received reference signal. The frequency range may be preset. In addition, the controller 120 decides whether or not the error is generated in the oscillator based on the changed oscillation signal.
A detailed operation of the controller 120 will be described below with reference to
A signal input to an ADC 340 of
In some exemplary embodiments, the controller 120 may change the oscillation signal within a frequency range so as to correspond to the reference signal. For example, the controller 120 may be implemented like a block 350 including an SRC 351, a burst locking PLL 353, a limiter 355, and the like, of
Referring to
As illustrated in
U sin(t)(+/−)V cos (ωt)
The controller 120 controls the burst lock SRC 430 so that frequencies of the reference signal 410 and the oscillation signal 420 coincide with each other. The controller 120 may control the burst lock SRC 430 to convert a sample rate, thereby changing the frequency.
Referring to
(3.5×106 Hz)×(1−500×106)˜(3.5×106 Hz)×(1−500×106)
That is, the frequency range becomes a range of 3.49825 MHz to 3.50175 MHz. Therefore, when a phase difference is generated within 3.5 kHz, the reference signal may be tracked in the frequency range of 500 ppm, such that the LOCK may be made.
The controller 120 controls a PI controller 445 to decrease the decided error. The PI controller 445 connects and uses an integral control integrating an error signal to generate a control signal in parallel with a proportional control. The PI controller 445 is mainly used in a feedback circuit. Since the PI controller 455 is a general circuit, a detailed description therefor will be omitted.
A center frequency table 447 illustrated in
According to an exemplary embodiment, the controller 120 changes at least one of the phase and the frequency of the received oscillation signal 420 within the frequency range through the feedback circuit so as to correspond to at least one of the phase and the frequency of the reference signal 410, as described above. In the case in which the LOCK is not possible, even though the feedback circuit is executed for a long period of time, the phases of the oscillation signal 420 and the reference signal 410 do not correspond to each other. Therefore, after a time enough to make the LOCK through the frequency tracking elapses, the controller 120 stops the feedback circuit, and extracts a U value among signal components of the reference signal 410 to decide whether or not the error is generated in the oscillator. For example, in the case of an NTSC signal, it has been known that a time of approximately 1 ms is used for the LOCK to be made. That is, a time for changing the oscillation signal 420 so that the frequency and the phase of the oscillation signal 420 coincide with those of the reference signal 410 is about 1 ms. The controller 120 performs a control to stop the change of the oscillation signal 420 when a threshold time elapses. The threshold time may be preset. In addition, the controller 120 decides that the oscillator is normally operated when the U value, which is a color signal component value extracted from the reference signal 410 at a point in time in which the change of the oscillation signal 420 is stopped, is a threshold value. The threshold value may be preset. When the LOCK of the oscillation signal 420 is made, that is, when the oscillator generates the oscillation signal 420 within an allowable frequency error range so as to correspond to the reference signal 410, the controller 120 decides that SPEC IN is made. To the contrary, in the case in which the oscillation signal 420 does correspond to the reference signal 410 due to the change within the frequency range, such that the UNLOCK is made, the controller 120 decides that SPEC OUT is made. Since the U value becomes a negative number in the case in which the SPEC IN is made, the controller 120 may decide whether or not the error is generated in the oscillator based on whether or not the U value is a threshold value set to a negative number. The threshold value may be preset. As another example, when V components of two adjacent pixel lines are added to each other to become 0, that is, when a phase difference between the V components of the two adjacent pixel lines is 180 degrees, the controller 120 decides that the oscillator is normally operated. Therefore, in the case of using the V components, the controller 120 may decide whether or not the error is generated depending on whether or not a value obtained by adding the V components of the two adjacent pixel lines to each other is 0, which is a threshold value.
According to an exemplary embodiment, in the case in which it is decided that the error is present in the oscillator, the controller 120 generates a control command for displaying a corresponding GUI. As an example, the controller 120 may control the display to display a notification message notifying that the error is generated. As another example, in the case of the remote diagnosis, the controller 120 may control the communication circuit to transmit a control command for allowing a GUI notifying an external diagnosing device that the error is generated to be displayed. In addition, the controller 120 may generate a control command for displaying a corresponding GUI even in the case in which the oscillator is normally operated. In the case in which error detection is performed on the plurality of oscillators, the controller 120 may control the display, or the like, to collect error detection results for the plurality of oscillators and provide the collected error detection results as one GUI.
The user may detect a defect of the oscillator used on the board using the broadcast signal as the reference signal through the error detector as described above. In addition, the user may decide whether or not the error is generated in the oscillator using an existing circuit present on the board without configuring a separate scope, a separate frequency counter, and the like.
Hereinafter, a method for detecting an error of an oscillator will be described with reference to
The error detector 100 sets a frequency range (S720). The frequency range that is set is determined in consideration of an error range allowable in each electronic device In the case in which the oscillator is actually operated, the error cannot be generated. Therefore, each electronic device has an allowable error range in which a problem is not generated in an operation thereof. The error detector 100 changes the oscillation signal within the frequency range so as to correspond to the reference signal (S730). In detail, the error detector 100 changes the oscillation signal using the feedback circuit so as to coincide with at least one of the phase and the frequency of the reference signal, thereby tracking the reference signal. In the case in which the tracking of the reference signal succeeds, it is called that the LOCK is made, and when the LOCK is made, the U value among components of the NTSC signal appears as a negative number. Therefore, the error detector 100 decides whether or not the U value extracted from the reference signal is a negative number (S740) after a threshold time in which a time for tracking the reference signal elapses. The error detector 100 may set the threshold value to the negative number.
When the U value extracted from the reference signal is not the negative number, which is set as the threshold value (S740-N), the error detector 100 decides that an error is generated in the oscillator (S750). To the contrary, when the U value extracted from the reference signal is the negative number, which is set as the threshold value (S740-Y), the error detector 100 decides that the oscillator is normally operated (S760). As another example, the error detector 100 may decide that the oscillator is normally operated when V value components of the NTSC signals applied to two adjacent pixel lines that are added to each other become 0. That is, alternatively, the error detector 100 may add the V value components of the NTSC signals of two adjacent pixel lines together, and determine if the result is equal to 0. In addition, the error detector 100 may generate a GUI notifying whether or not the error is generated in the oscillator.
The error detector 100 converts the selected and received oscillation signal into a digital signal (S820). The oscillation signal, which is an analog signal, is converted into the digital signal in order to primarily detect an output level. Since an operation is not performed when the output level of the oscillation signal is lower than a threshold level, even though the oscillator accurately outputs a frequency, a determination is made as to whether the error is generated in the oscillator. In order to convert the oscillation signal into the digital signal, the error detector 100 may use an ADC, a comparator, or the like. The error detector 100 detects the output level of the oscillation signal and decides whether or not the output level of the oscillation signal is higher than a threshold level (S830). When the detected output level of the oscillation signal is not higher than the threshold level (S830-N), the error detector 100 decides that the oscillator is not normally operated (S880) and directly generates a GUI notifying that the error is generated in the oscillator without performing the error detection using the frequency. On the other hand, when the detected output level of the oscillation signal is higher than the threshold level (S830-Y), the error detector 100 decides that the oscillator passes through a primary level test, such that the error detector 100 enters a method for detecting an error using the frequency.
The error detector 100 sets the trackable frequency range (S840). The error detector 100 changes the oscillation signal within the frequency range so as to correspond to the phase and the frequency of the reference signal (S850). The error detector 100 may change the oscillation signal using the feedback circuit including the SRC, the digital PLL, and the like. For example, the error detector 100 detects a phase difference between the reference signal and the oscillation signal and decreases the phase difference using the feedback circuit. After a threshold time used to track the reference signal using the feedback circuit elapses, the error detector 100 decides whether or not the oscillation signal is changed so as to correspond to the reference signal (S860). When the oscillation signal is changed so that at least one of the phase and the frequency thereof coincides with at least one of the phase and the frequency of the reference signal (S860-Y), the error detector 100 decides that the oscillator is normally operated (S870). The error detector 100 may generate a GUI for notifying that the oscillator is normally operated even in the case in which it is decided that the oscillator is normally operated. On the other hand, when the phases and the frequencies of the reference signal and the oscillation signal do not coincide with each other (S860-N), the error detector 100 decides that the error is generated in the oscillator. Therefore, the error detector 100 generates a GUI for notifying that the error is generated in the oscillator (S880). As another example, the error detector 100 may also transmit a notification message for notifying that the error is generated to an external device performing the remote diagnosis.
The error detector 100 changes the oscillation signal within the widest range among the plurality of frequency ranges in which the change of the oscillation signal is not attempted, so as to correspond to the reference signal (S930). For example, in the case in which the plurality of frequency ranges of 50 ppm, 100 ppm, and 300 ppm are set, when the oscillation signal is already changed with respect to 300 ppm, the error detector 100 will attempt to change the oscillation signal with respect to 100 ppm, which is a second widest frequency range, and then to 50 ppm which is the third widest range, and so on.
When it is decided that the oscillator is normally operated in a wider frequency range, the error detector 100 gradually narrows the frequency range to recognize a frequency range in which the oscillator may be operated. The error detector 100 decides that the oscillator is normally operated when a color component value extracted from the reference signal is a threshold value. The threshold value may be preset. For example, in the case of the U value, the threshold value may be a negative number. In the case in which the U value extracted from the reference signal, which is the NTSC broadcast signal, is the negative value (S940-Y), the error detector 100 decides whether or not changes of the oscillation signal are attempted in all of the set frequency ranges (S950). When frequency ranges in which the changes of the oscillation signal are not yet attempted remain (S950-N), the error detector 100 again returns to S930 to change the oscillation signal to the next widest range. When the changes of the oscillation signal are attempted in all of the frequency ranges (S950-Y), the error detector 100 decides that the oscillator is normally operated even in the narrowest frequency range (S970). Then, the error detector 100 generates a GUI for notifying the decided state of the oscillator (S980), in this case that the oscillator is normally operated even in the narrowest frequency range.
On the other hand, in the case in which the error detector 100 decides that the U value extracted from the reference signal, which is the NTSC broadcast signal, is not the negative value (S940-N), the error detector 100 decides that an error is generated in the oscillator in a frequency range when the U value is extracted (S960). The error detector 100 generates a GUI for notifying the decided state of the oscillator (S980), in this case that notifies in which of the plurality of frequency ranges the error is generated.
The user may decide whether or not the error is generated in the oscillator and in which frequency range the oscillator may be operated, through the method for detecting an error of an oscillator as described above.
In addition, program codes for performing the method for detecting an error according to various exemplary embodiments as described above may be stored in various types of recording media. In detail, the program codes may be stored in various types of recording media that is readable by a terminal, such as a random access memory (RAM), a flash memory, a read only memory (ROM), an erasable programmable ROM (EPROM), an electronically erasable programmable ROM (EEPROM), a register, a hard disk, a removable disk, a memory card, a universal serial bus (USB) memory, a compact-disk (CD) ROM, and the like.
According to various exemplary embodiments as described above, the error detection using the frequency of the oscillator may be performed using the broadcast signal as the reference signal. Therefore, the user uses circuits already provided on the board, thereby making it possible to conveniently detect the error of the oscillator.
Although various exemplary embodiments have been illustrated and described hereinabove, the present inventive concept is not limited to the above-mentioned specific exemplary embodiments, but may be variously modified by those skilled in the art without departing from the scope and spirit as disclosed in the accompanying claims. These modifications should also be understood to fall within the scope of the claims.
Number | Date | Country | Kind |
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10-2014-0130536 | Sep 2014 | KR | national |