KR101896926B1 - Tuner module using lookup table - Google Patents

Abstract

A method of processing a signal of a tuner module according to an exemplary embodiment of the present invention includes determining whether a lookup table exists or not and reading a signal intensity according to all frequencies in a tuner and a demodulator when not present, ; Outputting a video and a voice of a searched channel by searching the channel; Storing an AGC value read from the tuner and the demodulator in a variable; Deriving an optimal RSSI value by comparing the measured AGC value with a lookup table; And displaying the derived RSSI value on a TV screen.

Description

Tuner module using lookup table {TUNER MODULE USING LOOKUP TABLE}

The present invention relates to a tuner module and a signal processing method using a lookup table.

Generally, a signal transmitted from a mobile terminal is distributed in both directions by a directional coupler for measuring the standing wave ratio and for measuring received power.

The portion for measuring the standing wave ratio includes a fixed attenuator for attenuating the intensity of the signal to an appropriate level for signal processing, an amplifier for amplifying the attenuated signal, a detector for converting the power of the amplified signal into a voltage, And an analog-to-digital converter for converting the analog signal converted into the voltage into a digital signal.

On the other hand, the portion for measuring the power of the signal includes a fixed attenuator for attenuating the intensity of the signal to an intensity suitable for signal processing, a detector for converting the power of the attenuated signal into a voltage, And an analog-to-digital converter for converting the digital signal into a digital signal.

The signals converted into the digital signal by the analog-to-digital converter are input to the control unit, and the control unit calculates the power and the standing wave ratio of the received signal using the digital converted signals.

That is, in the conventional power meter, the AGC value read by the tuner and the demodulator is stored in a related variable, and the calculated value is inputted into a formula for deriving RSSI (Receive Signal Strength Indicator) value. For example, when the automatic gain control (AGC) value is 120 to 130, the RSSI value is calculated as -50 dBm.

However, the signal from one signal generator is read by the tuner and the demodulator according to the frequency while passing through several circuits in the middle. For example, when a signal of -50 dBm is output from the signal generator, there is a problem that the deviation due to the frequency is not properly reflected when the tuner and the demodulator read the signal with the AGC value of 120 at 177.5 MHz and the AGC value of 135 at 474 MHz do.

In order to solve the above problems, an embodiment of the present invention provides a tuner module and a signal processing method reflecting RSSI using a lookup table.

A method of processing a signal of a tuner module according to an exemplary embodiment of the present invention includes determining whether a lookup table exists or not and reading a signal intensity according to all frequencies in a tuner and a demodulator when not present, ; Outputting a video and a voice of a searched channel by searching the channel; Storing an AGC value read from the tuner and the demodulator in a variable; Deriving an optimal RSSI value by comparing the measured AGC value with a lookup table; And displaying the derived RSSI value on a TV screen.

According to an embodiment of the present invention, a precise RSSI value can be calculated by comparing the measured AGC value with a lookup table to derive an optimal RSSI value.

1 is a block diagram showing a configuration of a tuner module according to an embodiment of the present invention.
2 is a flowchart illustrating a process of deriving an RSSI value according to an embodiment of the present invention.
3 is a diagram illustrating a lookup table according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The details of other embodiments are included in the detailed description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent by reference to the embodiments described in detail below with reference to the accompanying drawings. Like reference numerals refer to like elements throughout the specification.

1 is a block diagram showing a configuration of a tuner module according to an embodiment of the present invention. 2, the tuner according to the embodiment includes a high pass filter 180, an LNA 200, an input tuner 202, an RF amplifier circuit 210, an RF tuner 204, An IF correlation inquiry path 225, and a demodulation unit 240.

The high pass filter 180 selectively passes only a high frequency band signal among the signals input through the antenna and transmits the high frequency band signal to the LNA 200.

The high pass filter 180 passes a signal of a required frequency band through a circuit having good frequency selectivity. The high pass filter 180 may include a serial resonant circuit or a parallel resonant circuit.

The LNA (Low Noise Amplifier) 200 has characteristics of a low noise ratio and a high amplification degree and selectively operates, and low-noise amplifies a high frequency signal received from the antenna.

The LNA 200 selectively operates by the supplied DC voltage. When the received high frequency signal is a weak electric field, the low noise amplification is performed. When the received high frequency signal is a strong electric field, the LNA 200 is turned off and bypassed . A bypass path may be formed in the LNA 200.

The input dynamic linker 202 includes a circuit for impedance matching of the RF amplifier circuit 210 and is designed to minimize insertion loss. The input dynamic linker 202 receives and tunes the signal of the LNA 200 and outputs the tuned signal to the RF amplifier circuit 210.

The RF amplification circuit 210 includes a circuit for amplifying an RF signal. The RF tuner circuit 204 includes a double tuning circuit to select a desired RF signal and make the frequency characteristic flat.

On the other hand, the receiving apparatus including the tuning circuit and the amplifying circuit can receive a broadcast signal transmitted at a frequency of a plurality of bands, for example, receive a UHF signal, a VHF-High signal and a VHF- have.

The intermediate frequency circuit unit 220 may receive the amplified signal through the RF amplification circuit 210 and may output the tuned signal as an intermediate frequency signal. The intermediate frequency circuit unit 220 may convert a signal received from the RF amplification circuit 210 into an intermediate frequency signal corresponding to a desired broadcast channel and output the intermediate frequency signal. The intermediate frequency circuit unit 220 may be configured as an MOPLL integrated circuit.

The intermediate frequency circuit unit 220 may include an AGC detection unit 221, an ADC unit 222, and an RSSI threshold value generation unit 223.

The AGC detector 221 detects a signal provided from the RF amplifier circuit 210 and converts the AGC signal into an AGC signal according to the level of the detected signal to output the AGC signal to the RF amplifier circuit 210 .

The AGC detector 221 converts an AGC signal into an AGC signal according to the level of the signal and provides the AGC signal to the RF amplifier circuit 210 to adjust the amplification degree. That is, in the strong signal condition, the AGC signal is outputted to the vicinity of 0 V to suppress the amplification of the RF amplification circuit 210 to the maximum, while when the AGC signal is in the weak electric field signal condition, the AGC signal is outputted to the vicinity of 4 V The amplification of the RF amplification circuit 210 can be maximized.

The ADC (Analog to Digital Converter) 222 converts the AGC signal provided from the AGC detector 221 into an ADC signal and outputs the ADC signal. That is, the ADC unit 222 may output an AGC signal provided from the AGC detection unit 221, for example, as an ADC signal of five levels ranging from 0 to 4.

Accordingly, the level of the signal is detected and converted to the AGC signal, and the AGC signal is output again to the ADC signal, so that the condition of the signal can be grasped through the ADC signal.

The RSSI threshold value generation section 223 includes a storage device for storing the RSSI threshold value corresponding to the AGC. The RSSI threshold value generator 223 may include a look-up table. The RSSI threshold corresponding to the AGC may be entered at the time of production of the look-up table or entered by the user during use.

The AGC value detected by the AGC detector 221 is compared with a lookup table to derive an optimum table value. For example, when the AGC value measured at frequency f1 (e.g., 177.5 MHz) is 127, it can be seen that the signal strength is between -50 dBm and -45 dBm compared to the lookup table. It can be seen from the proportional expression of AGC value and signal strength that it has a signal strength of -48.75 dBm.

The IF signal output from the intermediate frequency circuit unit 220 may be tuned and amplified and outputted by the IF tuning circuit 225.

The SAW filter 230 may output only the band of the digital broadcast frequency signal from the intermediate frequency signal output from the intermediate frequency circuit unit 220 or may pass the band of the analog broadcast frequency signal through the intermediate frequency signal.

The analog / digital demodulator 240 demodulates and outputs the analog broadcast frequency signal or digital broadcast frequency signal filtered by the filter.

At this time, the demodulation unit 240 may demodulate the analog / digital broadcast frequency signal into analog / digital audio and analog / digital video signals desired by the program and output the analog / digital broadcast frequency signal.

2 is a flowchart illustrating a process of deriving an RSSI value according to an embodiment of the present invention. As shown in FIG. 2, the presence or absence of a lookup table is determined, and if there is no lookup table, the tuner and the demodulator read signal strengths according to all frequencies to create a lookup table divided into frequency and signal strength.

Next, the channel search and the video and audio of the searched channel are output. Then, the AGC value read from the tuner and demodulator is stored in the variable. Next, the measured AGC value is compared with a lookup table to derive an optimum RSSI value. Next, the derived RSSI value is displayed on the TV screen.

3 is a diagram illustrating a lookup table according to an embodiment of the present invention. The vertical axis represents the value of the signal strength (dBm), the horizontal axis represents the frequency, and the AGC value corresponding to the horizontal axis and the vertical axis.

The features, structures, effects and the like described in the embodiments are included in at least one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects and the like illustrated in the embodiments can be combined and modified by other persons skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

Claims (5)

AGC detector;
An RSSI threshold generator for receiving an AGC value output from the AGC detector and outputting an RSSI value; And
And an analog-to-digital converter for converting the RSSI into a digital signal,
The RSSI threshold generator includes a lookup table divided into frequency and signal strength, compares the AGC value detected by the AGC detector with the lookup table to derive an optimal RSSI value,
Wherein the RSSI value is determined through a proportional expression of the AGC value and the signal strength. The method according to claim 1,
And the analog-to-digital converter connects to an AGC signal provided from the AGC detector and outputs the AGC signal as an ADC signal in five stages. 3. The method according to claim 1 or 2,
Wherein the AGC detector outputs an AGC signal of 0 V when the strong signal system is in the signal condition and outputs 4 V when the weak signal condition is the weak signal condition. Determining whether or not a lookup table exists, reading the signal strengths according to all frequencies in a tuner and a demodulator if they are not present, and creating a lookup table divided into frequency and signal strength;
Outputting a video and a voice of a searched channel by searching the channel;
Storing an AGC value read from the tuner and the demodulator in a variable;
Deriving an optimal RSSI value by comparing the measured AGC value with a lookup table; And
And displaying the derived RSSI value on a TV screen,
The step of deriving the optimum RSSI value may include the steps of: assigning an AGC value measured at a corresponding frequency to a lookup table; deriving a value of a signal strength corresponding to AGC through a proportional expression based on the substituted lookup table; / RTI >
Wherein the optimal RSSI value is determined through a proportional expression of the AGC value and the signal strength. delete

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