KR20070072172A - A method and a apparatus of detecting sync. signal for dmb mobile phone - Google Patents

Abstract

A synchronization apparatus and method of a DMB(Digital Multimedia Broadcasting) terminal are provided to control a hold unit to make an amplification level uniform when the DMB terminal detects a synchronization signal to receive a stabilized digital TV signal. A synchronization apparatus of a DMB terminal includes an RF(Radio Frequency) unit(100) for receiving a digital TV DMB signal, a synchronization unit(110) for detecting a DMB synchronization signal from the digital TV DMB signal, an intermediate frequency unit(130) for converting the DMB signal into an intermediate frequency signal, and a hold unit(140) for maintaining the DMB signal received from the intermediate frequency unit at a specific amplification rate and delaying the DMB signal. The synchronization apparatus further includes a controller(120) for controlling the operation of the hold unit, and a baseband unit(150) for converting the intermediate frequency DMB signal received from the hold unit into a baseband DMB signal and detecting the DMB signal according to the synchronization signal received from the synchronization unit.

Description

Synchronization device and method of DMB handheld terminal TECHNICAL FIELD [A METHOD AND A APPARATUS OF DETECTING SYNC. SIGNAL FOR DMB MOBILE PHONE}

1 is a functional diagram of a synchronization device of a DMB portable terminal according to the prior art;

2 is a flowchart illustrating a synchronization method of a DMB portable terminal according to the prior art;

3 is a picture showing a state of detection of a synchronization signal and a data signal according to an example of the prior art;

4 is a functional diagram of a synchronization device of a DMB portable terminal according to the present invention;

5 is a flowchart illustrating a synchronization method of a DMB portable terminal according to the present invention;

6 is a picture showing a state of detection of a synchronization signal and a data signal according to one embodiment of the present invention;

          ** Explanation of symbols on the main parts of the drawing **

100: high frequency unit 110: synchronization unit 120: control unit

130: intermediate frequency unit 140: hold unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the detection of a synchronization signal of a DM-type portable terminal which wirelessly receives a TV broadcast signal while moving. In particular, the amplification level of the DMB broadcast signal received by the synchronization signal is fixed, delayed, and outputted. The present invention relates to a synchronization device and a method of a DM mobile terminal for accurately detecting a DM broadcast signal while reducing BER.

The mobile terminal for mobile communication (MS: MOBILE STATION) monitors the mobile switching station (MSC: MOBILE SWITCHING CENTER) while moving freely in the service area formed by the corresponding base station (RAN: RADIO ACCESS NETWORK) of the registered system. It is a high-tech digital wireless communication device that communicates instantly with the desired party anytime and anywhere through the communication path established by the control and switching, and that the individual always carries and moves directly.

The communication method using the mobile terminal (MS) is based on the first (1G: 1st GENERATION) voice-level signal, the second generation (2G: 2nd GENERATION), the symbols, letters, numbers, graphics, etc. The data level message communication method to be used and the recent 3rd generation (3G: 3G GENERATION) are multimedia level communication methods which include a video signal in the audio level and the data level.

In addition to the communication use of the digital portable terminal, various additional service functions are provided to make the real life more convenient.

The additional service, which is developed and provided by a mobile terminal manufacturer, includes a camera, a Bluetooth, a wireless LAN, a radio, a game, an electronic calculator, a calendar, a clock, a call ring setting, and is developed by a mobile communication service provider and a content provider. In order to provide, text messages, video messages, online games, wireless Internet access, caller identification, etc., the additional services continue to be developed and added new kinds of functions.

Among the supplementary services of the mobile terminal (MS) as described above, a technology for receiving and transmitting data broadcast, radio (RADIO) broadcast, and TV (TELEVISION) broadcast signal has been recently developed and introduced. DMB: DIGITAL MULTIMEDIA BROADCASTING.

The DMB broadcast includes a terrestrial DMB (TDMB) method for receiving broadcast signals transmitted from the terrestrial and a satellite DMB (SDMB: SATELLITE DMB) for receiving broadcast signals transmitted from satellite (SATELLITE). There is a method, and in general, terrestrial DMB broadcasting (TDMB) is called DMMB broadcasting.

The third generation mobile terminal (MS) is provided with a function of communicating using voice and data level signals while looking at a counterpart using a video signal, and receiving and demodulating the broadcast signal of the DMB. When only the corresponding function unit is added, the DMB digital television broadcast signal may be received and viewed.

In order to receive and demodulate the DMV digital TV broadcast signal, it is necessary to detect the synchronization signal and detect and demodulate the digital TV system data according to the detected synchronization signal.

In one embodiment, the synchronization signal of the DMB method is a null section of 1.2 ms is periodically generated while a signal is input at a constant amplification rate, and a synchronization signal is detected by detecting the null section. The synchronization signal is repeatedly generated every 120 ms, and digital TV broadcast data is included in the 120 ms period between the synchronization signal and the next synchronization signal.

Accordingly, since the reception performance of the DMV digital TV is determined, it is necessary to develop a technique for accurately detecting and recognizing the synchronization signal represented by the null and reading the TV reception data without error.

Hereinafter, a synchronization method of a DMB portable terminal according to the prior art will be described with reference to the accompanying drawings.

It is attached to describe the prior art, Figure 1 is a functional block diagram of the synchronization device of the DM mobile terminal according to the prior art, Figure 2 is a flow chart of the synchronization method of the DM mobile terminal according to the prior art, Figure 3 The synchronization signal and data signal detection state photograph according to an example.

Referring to FIG. 1, the synchronization device of the conventional DMB portable terminal will be described. In the case where the DMB broadcast is to be received by the mobile terminal for mobile communication, the high frequency unit 10 is assigned to the DMB. Tuned to the received frequency band to receive the digital TV broadcast signal, and the received DM signal is applied to the synchronization unit 20 and the intermediate frequency unit 30, respectively.

The synchronization unit 20 receives the DMB broadcast signal and detects a null section for 1.2 ms when no signal is input. The synchronizer 20 recognizes the synchronization signal and outputs the corresponding signal to the base unit 60 that processes the baseband signal. .

The intermediate frequency unit 30 converts the DMB high frequency signal applied from the high frequency unit 10 into an intermediate frequency signal and outputs the intermediate frequency signal to the time constant unit 40, and the time constant unit 40 uses a 2 uF capacitor. The DMB intermediate frequency signal input by the time constant value is delayed and output to the base unit 60.

The base unit 60 converts the DMB intermediate frequency signal delayed from the time constant unit 40 into a baseband signal, and receives the error without any error by the synchronization signal applied from the synchronization unit 20.

However, in the case of a signal input to the base unit 60 and first applied after the synchronization signal is detected, the signal is amplified to a level LEVEL or higher than a gain GAIN set by AUTO GAIN CONTROL (AGC). It is applied in a state and is gradually input at the level by the controlled gain.

However, when the signal is amplified by more than the gain GAIN set as described above, the noise signal included in the DMB broadcast signal is detected and recognized as a normal signal, thereby causing an error in the DMB broadcast data. There is a problem that the synchronization is not matched, the screen is shaken, and in severe cases can not be received.

Hereinafter, referring to the attached method of FIG. 2, the synchronization method of the DMB portable terminal according to the related art will be described. Detects a synchronization signal of length ms (S20), delays the received DMB broadcast signal to an RC time constant value by a 2 uF capacitor connected in parallel with the time constant unit 40 (S30), and detected as described above. Since the digital data of the delayed DMB broadcast signal is detected by the synchronization signal, the digital TV broadcast signal is moved and received (S40).

3 is a state in which the amplification rate of the signal input following the synchronization signal increases instantaneously and gradually changes to the amplification rate of a controlled level.

Therefore, in the prior art having the above-described configuration, the noise signal is detected as a data signal due to the gain variation of the DM signal applied after the synchronization signal detection, and thus there is a large number of error occurrence rates (BER) in the detection of the DM signal. There is a problem.

According to the present invention, when the DM mobile terminal detects a synchronization signal, the hold unit is controlled to constantly control the amplification level. Therefore, the DM terminal for receiving a stable digital TV signal by improving the error occurrence rate of the received DB broadcast signal is provided. It is an object of the present invention to provide a synchronization device and method.

The present invention devised to achieve the above object comprises: a high frequency unit for wirelessly receiving and outputting a digital TV broadcast signal according to the DMV method by the control; A synchronization unit connected to the high frequency unit and detecting a DMB synchronization signal; An intermediate frequency unit connected to the high frequency unit and converting a high frequency DMB broadcast signal into an intermediate frequency signal; A hold unit which maintains the DMB broadcast signal applied from the intermediate frequency unit at a constant amplification rate and simultaneously delays and outputs the DMB broadcast signal; A control unit which controls and monitors an amplification level of the signal applied to the hold unit by a synchronization signal applied from the synchronization unit, and outputs the delayed level; And a base unit for converting an intermediate frequency DMB signal applied from the hold unit into a baseband DMB signal and detecting the same by a synchronization signal applied from the synchronization unit.

In addition, the present invention has been made in order to achieve the above object, the first step of determining whether to receive a DM broadcast signal by the DM mobile terminal; A second step of detecting a synchronization signal from the DMB broadcast signal received by the mobile terminal of the first step; A third step of activating and holding the hold part during the time when the synchronization signal is detected by the mobile terminal of the second step; And a fourth process of detecting and outputting a DMB broadcast signal by the portable terminal of the third process.

DETAILED DESCRIPTION OF THE EMBODIMENTS Hereinafter, a synchronization device and a method of a DMB portable terminal will be described with reference to the accompanying drawings.

4 is a functional block diagram of a DMB portable terminal according to the present invention, FIG. 5 is a flowchart illustrating a synchronization method of a DMB portable terminal according to the present invention, and FIG. The synchronization signal and data signal detection state photograph according to an example.

Referring to FIG. 4, the synchronization device of the DM mobile terminal according to the present invention will be described. The digital TV broadcasting signal of the DM TV method is wirelessly outputted according to the control signal applied from the DM mobile terminal controller 120. High frequency part 100 to say,

A synchronization unit 110 connected to the high frequency unit 100 and detecting a DMB synchronization signal;

A control unit 120 for controlling and monitoring the amplification level of the signal applied to the holding unit 140 by the synchronization signal applied from the synchronization unit 110, and delaying and outputting the signal;

An intermediate frequency unit 130 connected to the high frequency unit 100 and converting a high frequency DMB broadcast signal into an intermediate frequency signal;

The DMB broadcast signal applied from the intermediate frequency unit 130 is maintained at a constant amplification rate under a corresponding control and delayed to be output. The intermediate frequency (IF) DMB (DMB) applied from the intermediate frequency unit 130 is output. A hold unit 140 for delaying and outputting the signal while maintaining the signal at a constant amplification rate,

The base unit 150 converts the intermediate frequency DMB signal applied from the hold unit 140 into a baseband DMB signal and detects the DMB digital signal by the synchronization signal applied from the synchronizer 110.

Hereinafter, according to the present invention having the above configuration, a synchronization device of a DMB portable terminal will be described in detail with reference to the accompanying drawings.

The DMB broadcasting, in particular, in the case of terrestrial DMB broadcasting, divides a given frequency band by a code division multiple access (CDMA) method and broadcasts a voice signal in a digital manner, and a radio channel and a multimedia level. There are about 60 channels including TV channels for broadcasting signals and data channels for broadcasting data signals.

As described above, each channel (CH) of DMB broadcasting has a different content to be broadcasted according to its characteristics, for example, a channel for broadcasting news entirely, a channel for broadcasting sports contents, and a fishing content broadcasting. Channels, channels for mountaineering content, channels for music content, channels for entertainment content, channels for theatrical content, channels for movie content, channels for religious content, department stores channels, general culture There are various channels such as a channel for broadcasting content, a channel for broadcasting educational content, and the like, and each content CONTENTS also has a channel operated by a plurality of different operators.

As described above, the frequency band BANDWIDTH allocated to the terrestrial DMB broadcasting (TDMB) is 175.264 KHz to 214.736 KHz, and thus, an antenna (ANT) having a length designed based on an intermediate frequency of about 195 MHz of the band. ANTENNA).

When the antenna used for receiving the DMB broadcast signal matches the lambda which is the wavelength of the frequency used, the antenna receives the frequency signal with a high gain and matches the state. In the case of using an antenna having a length different from the wavelength calculated as described above, there is a characteristic that the antenna reception gain is drastically lowered because it is not matched (MISMATCHING).

The DMB portable terminal which guarantees mobility and portability uses an antenna of small length (ANTENNA) and simultaneously receives a TDMB signal and a mobile communication signal with a high antenna gain.

That is, in order to receive both a DMB broadcast signal and a mobile communication signal having different radio frequency bands (BANDWIDTH) with one antenna, both signals are not optimally received, but both signals are reduced in such a manner as to reduce a large number of antenna reception gains. Use an antenna that can receive all of them.

As described above, in the DM mobile terminal that receives and enjoys a digital TV broadcast using the mobile communication terminal, the DM broadcast signal is received by an antenna having a slightly lower gain, so the received DM signal must be amplified to a predetermined level.

The signal to be received wirelessly includes a signal to be obtained, but it is introduced by the surrounding environment and includes an unnecessary signal. The unnecessary signal is called a noise signal, and the noise signal removal is performed in various ways such as filtering, error cancellation, and the like. In general, the signal to be received has a high level, and the noise signal has a low level.

In the method of removing the noise signal, there is also a method of separating the signal and the noise signal to be obtained by amplifying the input signal to a predetermined level, and when using the method of separating the signal and noise by the level as described above When the amplification level or gain is changed, some noise signals are included and detected, thereby causing an error in the detected data.

Accordingly, the present invention is to reduce the BIT ERROR RATE (BER) of the DMB signal due to the variation of the gain or gain GAIN of the DMB portable terminal.

The high frequency unit 100 is set to receive a DMB frequency band signal under the control of the control unit 120 that controls and monitors the overall operation of the DMB portable terminal, and wirelessly receives the DMB broadcast signal. Applied to the synchronization unit 110 and the intermediate frequency unit 130, respectively.

The synchronization unit 110 detects a 1.2 ms synchronization (SYN) signal repeatedly transmitted in a 120 ms period according to the corresponding standard of the DMB signal, and outputs the SYN signal to the control unit 120 and the base unit 150, respectively.

The intermediate frequency unit 130 receives the high frequency (RF) signal of the DMB broadcast received by the high frequency unit, down-converts to a predetermined intermediate frequency (IF) signal, and outputs it to the hold unit 140.

The controller 120 monitors and controls each functional unit of the DM mobile terminal to operate normally, and controls the hold unit during the time when the synchronization signal is input by a synchronization signal applied from the synchronization unit 110. Thus, the gain of amplifying the signal input to the hold portion is made constant, and the signal is delayed and output.

The hold unit 140 is configured to amplify a signal applied from the intermediate frequency unit 130 by the corresponding signal applied from the control unit 120 to a level of a constant constant equal to a conventional gain level. At the same time, a delay is output while the control signal of the controller is applied to the base 150.

The base unit 150 converts an intermediate frequency (IF) signal applied through the hold unit 140 into a base band (BB) signal, and at the same time, a synchronization (SYNC) applied from the synchronization unit 110. The DM broadcast signal is detected by the signal.

The base unit 150 receives a synchronization signal from the synchronization unit 110 in units of 120 ms cycles and receives a 1.2 ms synchronization signal from the synchronization unit 110 according to a DMB broadcasting standard. The control unit 120 controls the hold unit 140 to delay and output an intermediate frequency DMB broadcast signal for 1.2 ms and to amplify to a gain level equal to a gain level amplified previously. To monitor the output.

6 is a diagram illustrating a state in which a DMB signal input according to the present invention is amplified with a constant gain level, and the waveform of the intermediate frequency DMB signal IF_AGC on the upper left is applied. If so, as shown in the middle on the right. A picture of the DMB signal waveform state that is delayed and output by the gain hold signal AGC_HOLD output from the controller 120 and amplified to a constant gain level as shown below is shown.

Therefore, according to the present invention having the above configuration, since the control unit 120 controls and monitors the amplification output at a constant amplification rate by the hold control signal applied to the holding unit 140, the base unit 150 synchronizes the DMB broadcasting signal. In the case of detecting by a signal, since the amplification rate is amplified by a constant gain, when the DMB broadcasting signal is separated by the level, there is an advantage of improving the noise signal.

Hereinafter, referring to FIG. 5, the synchronization method of the DMB portable terminal according to the present invention will be described. The DMMB portable terminal may be configured to determine whether to receive a digital TV broadcast signal, which is a digital TV broadcast. Process (S100),

The SYNC signal is detected from the DM broadcast signal received by the mobile terminal of the first step S100, and the SYNC signal in 1.2 ms unit is detected from the DM broadcast signal received by the synchronizer. A second process (S110) for detecting and outputting the base unit 150 and the control unit 120, respectively;

The hold unit 140 is activated and controlled during the time when the synchronization signal is detected by the portable terminal of the second step (S110), while the hold signal is detected and applied from the synchronization unit 110. A third step (S120) of enabling the control unit 140 to amplify and delay the DMB signal to a predetermined level and output the delayed signal;

Detecting and outputting a DMB broadcast signal by the portable terminal of the third process (S120), and being applied in a delayed state from the hold unit 140 by the mobile terminal base unit 150 of the third process (S120). A fourth process (S130) of detecting and outputting a DMB signal by the synchronization signal applied from the synchronization unit 110 is performed.

Hereinafter, the present invention having the above-described configuration will be described in detail with reference to the accompanying drawings.

The control unit 120 of the DMB portable terminal determines whether to receive a digital TV broadcast signal by DM broadcast in a mobile state according to the control command (S100), and determines the DMB broadcast signal in the determination (S100). If it is determined that the reception is to be performed, the synchronization unit 110 is controlled to detect a synchronization signal having a length of 1.2 ms based on a standard among the DMB broadcast signals that the high frequency unit 100 receives wirelessly (S110).

In this case, the high frequency unit 100 applies a DMB broadcast signal, which is wirelessly received as a high frequency (RF) signal, to the intermediate frequency unit 130, converts it into an intermediate frequency (IF) signal, and holds the converted intermediate frequency signal. Applied to the unit 140.

As described above, the control unit 120 of the DM mobile terminal which detects the synchronization signal controls the hold unit 140 to delay a signal input to the hold unit 140 while the synchronization signal is generated. At the same time, activation is controlled so that the signal input to the holding unit 140 is amplified to a level of a certain gain GAIN (S120).

The DM broadcast signal output from the hold unit 140 activated and controlled as described above and the synchronization signal detected from the synchronization unit 110 are respectively applied to the base unit 150, and the base unit 150 is the hold unit. The intermediate frequency (IF) DMB broadcast signal applied from 140 is converted into a baseband (BB) DMB broadcast signal, and digitally generated by the synchronization signal applied from the synchronizer 110 from the converted DMB broadcast signal. Detects a TV broadcast signal.

Since the base unit 150 receives and processes the DMB broadcast signal amplified to a certain gain level by the hold unit, when the noise is removed by the level, the error occurrence rate BER is improved.

Therefore, the present invention having the above-described configuration has the advantage of maintaining a stable screen because it accurately detects and outputs a DMV broadcast signal of a digital TV received while moving.

According to the present invention, the DM broadcast signal received by the DM mobile terminal is amplified and outputted at a constant gain level while detecting the synchronization signal and the TV broadcast signal, thereby improving the error occurrence rate due to the noise signal, and There is an industrial use effect to improve the reception state of the TV signal.

In addition, since the digital TV signal is detected and output without error even in a moving state, there is a convenient effect of increasing reliability and improving preference.

Claims (8)

A high frequency unit for wirelessly receiving and outputting a digital TV broadcasting signal by DMV according to the control; A synchronization unit connected to the high frequency unit and detecting a DMB synchronization signal; An intermediate frequency unit connected to the high frequency unit and converting a high frequency DMB broadcast signal into an intermediate frequency signal; A hold unit which maintains the DMB broadcasting signal applied from the intermediate frequency unit at a constant amplification rate and delays and outputs the same by the control; A control unit which controls and monitors the amplification level of the signal applied to the hold unit by constant and delayed output by the synchronization signal applied from the synchronization unit; And a base unit for converting the intermediate frequency DMB signal applied from the hold unit into a baseband DMB signal and detecting the intermediate frequency DMB signal by the synchronization signal applied from the synchronization unit. The method of claim 1, wherein the hold unit, And synchronously delaying and outputting the intermediate frequency DMB signal applied from the intermediate frequency unit under the control of the controller. The method of claim 1, wherein the control unit, Receiving a synchronization signal detected by the synchronization unit, controlling the hold unit to maintain a constant amplification level, and controlling and monitoring the signal to delay and output the signal. The method of claim 1, wherein the base portion, And converting the intermediate frequency DMB digital signal applied from the hold unit into a baseband DMMB digital signal, and detecting the DMMB digital signal by a synchronization signal applied from the synchronization unit. Device. A first process of determining whether a DMB broadcast signal is received by the DMB terminal; A second step of detecting a synchronization signal from the DMB broadcast signal received by the mobile terminal of the first step; A third step of activating and holding the hold part during the time when the synchronization signal is detected by the portable terminal of the second step; And a fourth process of detecting and outputting a DMB broadcast signal by the portable terminal of the third process. The method of claim 5, wherein the second process, And detecting the synchronization signal from the DM broadcast signal received by the mobile terminal synchronization unit of the first step and outputting the synchronization signal to the base unit and the control unit, respectively. The method of claim 5, wherein the three process, And a step of activating and controlling the hold unit to amplify, delay, and output the DMB signal to a predetermined level while the synchronization signal detected and applied by the synchronization unit is input by the portable terminal controller of the second process. Synchronization method of the DM mobile terminal. The method of claim 5, wherein the fourth process, And detecting and outputting a DMB signal applied in a delay state from the hold unit by a base unit of the third process by a synchronization signal applied from the synchronizer.

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