Linearization compensation system of digital TV relay apparatus and method thereof
First Claim
1. A linear compensation system, comprising:
- a transmitting unit configured to modulate a data to a first intermediate frequency (IF) signal, up convert the first IF signal to an RF signal, amplify the RF signal to a predetermined level using a power amplifier (PA) and transmit the amplified RF signal; and
a linear compensation unit configured to vary a step size of an adaptive equalizer according to whether a signal-to-noise ratio (SNR) for an output signal of the PA satisfies a prescribed standard, and output a selected linear compensation coefficient to the modulator, wherein the linear compensation unit computes error values by determining differences between output values of the adaptive equalizer and a reference signal, computes an average error value of the computed error values, and variably varies the step size of the adaptive equalizer until a current error value if less than a predetermined value of a previous error value.
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Accused Products
Abstract
A linear compensation system of a digital TV relay or other apparatus preferably includes a transmitting unit configured to modulate a data to an intermediate frequency (IF) signal, up convert the IF signal to an RF signal, and amplify the RF signal to a predetermined level using a high power amplifier (HPA). The system also includes a linear compensation unit to preferably directly vary a step size of an adaptive equalizer according to whether a signal-to-noise ratio (SNR) or an error vector magnitude (EVM) for an output signal of the HPA satisfies an advanced television systems committee (ATSC) or other standard. The linear compensation unit is thus configured to output an improved linear compensation coefficient to a modulator of the transmitting unit.
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Citations
24 Claims
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1. A linear compensation system, comprising:
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a transmitting unit configured to modulate a data to a first intermediate frequency (IF) signal, up convert the first IF signal to an RF signal, amplify the RF signal to a predetermined level using a power amplifier (PA) and transmit the amplified RF signal; and
a linear compensation unit configured to vary a step size of an adaptive equalizer according to whether a signal-to-noise ratio (SNR) for an output signal of the PA satisfies a prescribed standard, and output a selected linear compensation coefficient to the modulator, wherein the linear compensation unit computes error values by determining differences between output values of the adaptive equalizer and a reference signal, computes an average error value of the computed error values, and variably varies the step size of the adaptive equalizer until a current error value if less than a predetermined value of a previous error value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A linear compensation system, comprising:
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a transmitting unit configured to modulate an image data to a first intermediate frequency (IF) signal, up convert the first signal to an RF signal, amplify the RF signal to a prescribed level using a high powered amplifier (HPA), and transmit the amplified RF signal;
a correction circuit configured to convert the output signal of the HPA to a digital I/Q signal; and
a computer configured to receive the digital I/Q signal outputted from the correction circuit, update a step size of an adaptive equalizer according to one of a signal-to-noise ratio (SNR) for the output signal of the HPA and an error vector magnitude value (EVM), and output a linear compensation coefficient, wherein the computer computes error values by determining differences between output values of the adaptive equalizer and a reference signal, computes an average error value of the computed error values, and variably varies the step size of the adaptive equalizer until a current error value if less than a predetermined value of a previous error value. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A linear compensating method in which an image data is modulated into an intermediate frequency (IF) signal by a modulator, converted to an RF signal, amplified to a prescribed level and outputted by an HPA, comprising:
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determining whether a first SNR for an output signal of the HPA satisfies a standard;
computing an error value average for an output signal of an adaptive equalizer;
fixing the computed error value average as a step size of the adaptive equalizer when the computed error value average is in a predetermined range;
computing a second SNR; and
converting a coefficient of the adaptive equalizer and compensating a non-linearity of the HPA where one of the second SNR and the EVM satisfy the standard by more than a predetermined number, wherein the predetermined range is less than a predetermined value of a previous error value average. - View Dependent Claims (20)
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21. A linear compensating method in which an image data is modulated into an intermediate frequency (IF) signal by a modulator, converted to an RF signal, amplified to a prescribed level and outputted by an HPA, comprising:
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determining whether a first SNR for an output signal of the HPA satisfies a standard;
computing an error value average for an output signal of an adaptive equalizer;
fixing the computed error value average as a step size of the adaptive equalizer when the computed error value average is in a predetermined range;
computing a second SNR; and
converting a coefficient of the adaptive equalizer and compensating a non-linearity of the HPA where one of the second SNR and the EVM satisfy the standard by more than a predetermined number, wherein computing an error value average comprises;
converting the output signal of the HPA into a digital I/Q signal;
comparing the digital I/Q signal with a reference signal and computing the first SNR;
determining whether the first SNR as computed satisfies the standard;
driving the adaptive equalizer if the first SNR does not satisfy the standard; and
producing error values for the output signal of the adaptive equalizer and computing an average value of the produced error values.
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22. A linear compensating method in which an image data is modulated into an intermediate frequency (IF) signal by a modulator, converted to an RF signal, amplified to a prescribed level and outputted by an HPA, comprising:
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determining whether a first SNR for an output signal of the HPA satisfies a standard;
computing an error value average for an output signal of an adaptive equalizer;
fixing the computed error value average as a step size of the adaptive equalizer when the computed error value average is in a predetermined range;
computing a second SNR; and
converting a coefficient of the adaptive equalizer and compensating a non-linearity of the HPA where one of the second SNR and the EVM satisfy the standard by more than a predetermined number, wherein computing the second SNR comprises;
determining whether a current error value average is less than a predetermined value of a previous error value average;
computing one of the second SNR and the EVM using the output signal of the adaptive equalizer if the current error value average is less than a predetermined value of the previous error value average; and
setting the current error value average as the step size and updating the coefficient of the adaptive equalizer if the current error value average is not less than the predetermined value of the previous error value average. - View Dependent Claims (23, 24)
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Specification