KR20070040858A - Tuner auto-detecting channel selectively - Google Patents

Abstract

The tuner for selectively processing automatic tuning according to the present invention includes a synchronization processor for synchronizing the received RF signal to select a signal corresponding to a set channel, demodulating the selected RF signal into a digital signal, and detecting signal strength to control gain. And a demodulator for transmitting a signal, receiving the selected RF signal from the synchronization processor, determining signal strength in comparison with the gain control signal, and determining that the RF signal is a strong electric field signal having a predetermined value or higher. A channel setting unit storing channel information corresponding to the RF signal determined as the system signal; And an AGC control circuit which adjusts the gain of the gain control signal and sets the voltage of the gain control signal low to reduce the value of the strong electric field signal as the criterion.

According to the present invention, by eliminating unnecessary signals from tuning targets, waste of hardware resources of tuners such as memory and arithmetic circuits can be prevented, and the time required for performing the automatic tuning function can be saved and the load of the computing circuits can be reduced. Since the automatic tuning process can be performed quickly, there is an effect that the user can tune to only a broadcast having good broadcast reception sensitivity and faithfully display it in a limited number of display spaces.

Description

Tuner auto-detecting channel selectively}

1 is a block diagram schematically showing the components of a tuner according to the prior art;

FIG. 2 is a block diagram schematically illustrating components of a tuner for selectively processing automatic tuning according to an embodiment of the present invention. FIG.

3 is a flow chart illustrating a method for selectively processing automatic tuning on a tuner in accordance with an embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

100: Tuner for optional automatic tuning

110: high band pass filter 120: first band pass filter

130: RF amplifier 140: second band pass filter

150: oscillator 160: mixer

170: saw filter 180: demodulator

190: phase synchronization circuit 200: antenna

300: channel setting unit 400: AGC control circuit

The present invention relates to a tuner provided in a system for transmitting and receiving radio frequency signals, and more particularly, to a tuner that detects signal strength and selectively processes automatic tuning.

Recently, a transmission / reception system for using services such as DMB (Digital Multimedia Broadcasting), DBS (Direct Broadcast Satellite), etc. has been developed. Such a transmission / reception system not only reproduces multimedia data but also has a large capacity memory and a hard disc drive (HDD). And storage means such as a DVD (Digital Versatile Disc) device.

Transceiver systems, such as high-definition digital television (HDTV) or digital set-top boxes, all have a built-in tuner. The tuner is connected to the antenna or cable receiver and allows you to see the particular channel you want to watch.

As the digital broadcasting era gets full swing, high-definition and high-definition of broadcasts are recognized as an important aspect. Therefore, much research is being conducted in terms of reception performance. In other words, numerous field tests have been conducted to develop the receiver chip and related RF components or verify the performance of the developed product, and it is important for digital broadcasting systems to maintain more stable reception performance in the field under various conditions.

In particular, when the transmission / reception system is installed in a moving means such as a vehicle, the tuner has a function of selecting a signal that can be received in a moving area and displaying the predetermined number of channels. Since the screening function is performed on the signal and the automatic tuning is performed, a lot of throughput and time are required.

1 is a block diagram schematically showing the components of the tuner 10 according to the prior art.

First, the high band filter 11 connected to the antenna 20 filters the corresponding high frequency band signal, and the first band pass filter 12 filters only the narrow frequency band signal among the filtered high frequency signals.

The RF amplifier 13 amplifies the received signal into a signal of a size that can be processed in the RF stage, and the second bandpass filter 14 suppresses an unnecessarily amplified signal among the signals amplified by the RF amplifier. Extract only the signal.

In addition, the phase synchronization circuit 19 and the mixer 16 detect the synchronization signal of the signal passed through the second band pass filter 14, select a signal corresponding to the channel set by the user, and the saw (saw) The filter 17 filters the high frequency radio signal into a signal of an intermediate frequency band which can be processed by the demodulator.

The demodulator 180 demodulates the satellite signal VSB. At this time, the strength of the signal is detected by generating a gain control signal (RF AGC) by sensing the strength of the signal and transmitting the gain control signal to the RF amplifier 13. Adjust it.

The channel setting unit 30 receives the tuned signal from the phase synchronization circuit 19 and stores channel information corresponding to the tuned signal in the memory to process the automatic channel selection.

In general, in areas with high mountainous terrain or high-rise buildings, signal interference due to multi-channels is severely generated, and a limiting sensitivity is a sensitive criterion for receiving performance. The limiting sensitivity is the power (dB) of the RF signal. It provides a criterion that is sensitive enough to determine the reception based on the difference of about 1dB of the measured signal strength. Therefore, whether the digital broadcast signal is received or not is determined by the signal strength according to the signal state of each field.

Therefore, when the received signal is a weak electric field signal that cannot be broadcast, the tuner does not need to process it as automatic tuning. Despite this reason, conventionally, all signals are tuned and stored as a channel, so hardware resources are unnecessary. There is a problem that is used, and takes a lot of processing time.

In addition, even if a user selects an auto-tuned channel to determine a broadcast, a situation in which a broadcast condition is not good may occur.

Therefore, in the present invention, in the case of a weak field signal that is difficult to function as a broadcast signal, the received signal is passed without tuning, and only the received signal judged as a strong field signal is tuned and stored as a channel so that unnecessary channels are automatically excluded from the tuning target. Its purpose is to provide a tuner that can be used.

In order to achieve the above object, a tuner for selectively processing automatic tuning according to the present invention comprises a synchronization processor for selecting a signal corresponding to a set channel by synchronizing a received RF signal, the selected RF signal as a digital signal And a demodulator for demodulating and detecting a signal strength and transmitting a gain control signal, receiving the selected RF signal from the synchronization processor, and comparing the gain control signal to determine a signal strength. A channel setting unit for storing channel information corresponding to an RF signal determined as a strong electric field signal when it is determined that the electric field signal is greater than a numerical value; And an AGC control circuit which adjusts the gain of the gain control signal and sets the voltage of the gain control signal low to reduce the value of the strong electric field signal as the criterion.

In addition, the AGC control circuit provided in a tuner for selectively processing automatic tuning according to the present invention receives the gain control signal from the channel setting unit, recognizes the original gain value, and outputs the gain control signal from the demodulator. It is characterized by adjusting the gain.

Further, the strong electric field signal value as the criterion for determination used in the tuner for selectively processing automatic tuning according to the present invention is characterized by being 35 dBuv to 45 dBuv.

In addition, the AGC control circuit provided in the tuner for selectively processing automatic tuning according to the present invention is characterized in that the channel setting unit is operated when processing the automatic tuning function.

In addition, the AGC control circuit provided in a tuner for selectively processing automatic tuning according to the present invention includes a switching circuit at a connection end with the channel setting unit, and the channel setting unit processes the automatic tuning function. It is characterized in that the operation.

Hereinafter, a tuner for selectively processing automatic tuning according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a block diagram schematically illustrating the components of a tuner (hereinafter referred to as "tuner according to the present invention") 100 for selectively processing automatic tuning according to an embodiment of the present invention. In the tuner 100 according to the present invention is to be applied to the DBS receiving system.

For reference, DBS (Direct Satellite Broadcasting Satellite) refers to a broadcast service that sends a radio wave directly to a terrestrial receiving system using a broadcast satellite, and usually receives a radio wave by using a small parabolic antenna dedicated to satellite broadcast reception. .

Briefly, the characteristics of DBS are as follows.

First, SHF, a higher frequency band than VHF / UHF, is used.

Second, since the satellite transmits about 36,000 km of orbit over the equator, it can transmit radio waves nationwide with one satellite, and can solve the astigmatism area generated by mountains or skyscrapers.

Third, new services such as text multicasting, multichannel still image broadcasting, PCM broadcasting, and high-definition TV broadcasting are possible due to the use of the broadband SHF band.

Fourth, communication satellites provide services through earth stations, while broadcast satellites transmit radio waves directly to individual transmission and reception systems.

Therefore, the tuner 200 according to the present invention processes the high frequency signal of the 3GHz band.

Referring to FIG. 2, a tuner 100 for selectively processing automatic tuning according to an embodiment of the present invention includes a high pass filter (HPF) 110 and a first pass filter (BPF) (bypass filter (BPF)). 120), the RF amplifier 130, the second band pass filter 140, the oscillator 150, the mixer 160, the saw filter 170, the demodulator 180 and the phase synchronization circuit 190 The high band filter 110 is connected to the antenna 200, and the demodulator 180 and the phase synchronization circuit 190 are connected to the channel setting unit 300.

As the antenna 200, a reflector antenna or a flat antenna using a microstrip line is preferably used. The reflector antenna or the flat antenna has high gain characteristics and circular polarization characteristics (broadcast signal has circular polarization characteristics). Because it must be provided in each receiving system, there is an advantage that the size is small, cheap, and easy to install.

The high band filter 110 preferentially filters a signal having a high frequency band or more allocated to the tuner 100 according to the present invention, and the first band pass filter 120 again selects a narrow band from among the filtered high frequency signals. Filter only frequency signals.

The RF amplifier 130 amplifies the received signal into a signal of a size that can be processed in the RF stage, and amplifies the received signal to a signal of 10 dB or less due to a problem with a strong electric field signal.

The RF amplifier 130 is designed to suppress the signal-to-noise ratio is reduced by amplifying the noise generated inside the amplifier in amplifying the satellite signal to a signal size that can be processed in the demodulator.

The second band pass filter 140 filters only the signals processed by the mixer 160 and the phase synchronization circuit 190 among the signals amplified by the RF amplifier.

The phase synchronization circuit 190 and the mixer 160 detect a synchronization signal of a signal that has passed through the second band pass filter 140, select a signal corresponding to a channel set by a user, and demodulate the selected signal. To pass.

That is, the phase synchronization circuit 190 includes a vibrator 150 to synchronize and convert a channel input by a user into a corresponding frequency signal, and the mixer 160 detects a synchronization signal among high frequency radio signals based on the reference. .

As the vibrator 150, a crystal oscillator is usually used.

The saw filter 170 filters a high frequency radio signal into a signal of an intermediate frequency band that can be processed by the demodulator 180, and the demodulator 180 demodulates the synchronized satellite signal by VSB (Vestigial Side Band) demodulation. (TS; Transport Stream) data is generated.

In addition, the demodulator 180 senses signal strength to generate a gain control signal (RF AGC) by detecting signal strength and transmits the gain control signal to the RF amplifier 130. Adjust the signal strength.

Meanwhile, the channel setting unit 300 receives the tuned RF signal from the phase synchronization circuit 190, receives the gain control signal from the demodulator 180, and determines the strength of the received radio signal so that the wireless signal is a strong electric field. Determine whether it is or weak electric field.

At this time, the AGC control circuit 400 is connected to the demodulator 180 to adjust the gain of the gain control signal to set the voltage of the gain control signal low, which is a signal value as a criterion for determining the strong and weak electric fields. It is artificially reduced.

The AGC control circuit 400 has a structure in which an input terminal is connected to the channel setting unit 300 and an output terminal is connected to the demodulator 180, thereby receiving a gain control signal originally set from the channel setting unit 300 to gain. The numerical value is recognized and the gain of the gain control signal transmitted from the demodulator 180 is adjusted.

In artificially reducing the signal value, the AGC control circuit 400 adjusts the voltage of the gain control signal to be about 40 dBuv as a criterion for the determination of the weak field signal.

As such, when the voltage of the gain control signal (voltage of the RF AGC) is artificially controlled and gain is adjusted, the channel setting unit 300 performs an automatic tuning function accordingly, that is, the radio signal is about 40 dBuv or more. If it is a numerical value, it is determined that it is a strong electric field signal, and if it is less than about 40 dBuv, it is determined that it is a weak electric field signal.

For reference, the weak field signal having a value less than about 40 dBuv has a voltage level of 0V to 4V.

If it is determined that the radio signal is a weak field signal, the channel setting unit 300 skips the radio signal, and if it is determined that the radio signal is a strong electric field signal, recognizes the radio signal and stores channel information corresponding thereto. .

Accordingly, the channel setting unit 300 skips the channel of the weak field signal having an unstable reception state without tuning the channel, unlike the conventional channel selection method that stores the channels of all the signals input through the antenna. By tuning only a channel corresponding to the channel, only necessary signals can be tuned.

As described above, the AGC control circuit 400 for controlling the RF AGC voltage is preferably operated only when the channel setting unit 300 processes the automatic tuning function. For example, the AGC control circuit 400 and the channel setting unit ( By providing a switching circuit at the connection with the 300, it is possible to implement a selective operation of the AGC control circuit 400.

When the channel setting unit 300 performs the auto tuning function while the switching circuit is normally in an off state, the switching circuit may receive a control voltage of about 2V from the channel setting unit 300 to start a switching operation.

Hereinafter, a method of selectively processing automatic tuning on a tuner according to an embodiment of the present invention will be described with reference to FIG. 3.

3 is a flowchart illustrating a method for selectively processing automatic tuning on a tuner according to an embodiment of the present invention.

First, when a wireless signal is introduced through the antenna 200, the high band filter 110, the first band pass filter 120, the second band pass filter 140 processes the filtering as described above, RF The amplifier 130 amplifies the filtering signal into a signal having a size that can be processed in the RF terminal (S10).

The phase synchronization circuit 190 and the mixer 160 detect a synchronization signal of a signal that has passed through the second band pass filter 140, select a signal corresponding to a channel set by a user, and demodulate the selected signal. And at the same time as the channel setting unit 300 (S12).

Hereinafter, the functions of the phase synchronization circuit 190, the mixer 160, the vibrator 150, the saw filter 170, and the demodulator 180 will be described with reference to the above description, and automatic tuning according to an embodiment of the present invention will be described. Only those features that are directly related to how they are handled will be discussed.

The demodulator 180 senses the signal strength to generate a gain control signal (RF AGC) and transmits the gain control signal to the channel setting unit 300.

The channel setting unit 300 transmits a gain control signal to the AGC control circuit 400, and the AGC control circuit 400 adjusts the gain of the gain control signal to set the voltage of the gain control signal to a low level. The signal value as a criterion of the electric field is artificially reduced (S14).

Subsequently, the channel setting unit 300 receives a tuned signal from the phase synchronization circuit 190, and receives a gain control signal (RF AGC voltage) set low from the AGC control circuit 400 to determine the signal strength. (S16).

As a result of the determination, when the signal strength is determined to be a strong electric field signal of 40 dBuv or more (S18), the channel setting unit 300 stores the channel information corresponding to the signal in a memory (not shown) for automatic tuning (S22). .

On the other hand, if it is determined that the signal strength is less than 40dBuv weak field signal (S18), the channel setting unit 300 determines the next received signal without storing the channel information of the signal in the memory (S20). .

Through this process, the channel setting unit 300 skips the channel of the weak field signal having an unstable reception state, and selects only the necessary signal by selecting only the channel corresponding to the strong field signal.

The present invention has been described above with reference to the preferred embodiments, which are merely examples and are not intended to limit the present invention, and those skilled in the art to which the present invention pertains do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications are not possible that are not illustrated above. For example, each component specifically shown in the embodiment of the present invention can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

The present invention has the following effects.

First, according to the tuner that selectively processes automatic tuning according to the present invention, unnecessary signals are excluded from the tuning target, thereby preventing waste of hardware resources of the tuner such as memory and arithmetic circuit.

Second, according to the present invention, since the time required for performing the automatic tuning function is reduced and the load of the calculation circuit can be reduced, the automatic tuning can be processed quickly. Therefore, only a limited number of displays can be tuned to the user. There is an effect that can be displayed faithfully in the space.

Claims (5)

A tuner including a demodulator for synchronizing a received RF signal to select a signal corresponding to a set channel, and a demodulator for demodulating the selected RF signal into a digital signal and detecting a signal strength to transmit a gain control signal. The selected RF signal is received from the synchronization processor, and the signal strength is determined by comparing with the gain control signal. When the RF signal is determined to be a strong electric field signal having a predetermined value or more, the RF signal is determined as a strong electric field signal. A channel setting unit for storing channel information; And And an AGC control circuit for adjusting the gain of said gain control signal to set the voltage of said gain control signal low, thereby reducing the value of the strong electric field signal as said determination criterion. The method of claim 1, wherein the AGC control circuit And receiving the gain control signal from the channel setting unit, recognizing the original gain value, and adjusting the gain of the gain control signal sent from the demodulator. The value of the strong electric field signal as the determination criterion according to claim 1, An optional automatic tuner, characterized in that from 35dBuv to 45dBuv. The method of claim 1, wherein the AGC control circuit And the channel setting unit is operated when processing the automatic tuning function. The method of claim 4, wherein the AGC control circuit And a switching circuit provided at a connection end with the channel setting unit, wherein the channel setting unit is operated when the channel setting unit processes the automatic tuning function.

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