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OFDM demodulation apparatus

A boundary and symbol technology, applied in the field of demodulators, which can solve problems such as control transfer and complex control

Inactive Publication Date: 2005-11-02
SONY CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Long control transfers require complex control

Method used

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  • OFDM demodulation apparatus
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  • OFDM demodulation apparatus

Examples

Experimental program
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Effect test

no. 1 example

[0110] The present invention will be described in detail below with respect to the OFDM receiver as the first embodiment of the present invention.

[0111] Overview of OFDM Receiver

[0112] FIG. 6 is a block diagram of an OFDM receiver according to a first embodiment of the present invention.

[0113] As shown in FIG. 6, an OFDM receiver 1 as a first embodiment of the present invention includes an antenna 2, a tuner 3, a band-pass filter (BPF) 4, an A-D conversion circuit 5, a clock generation circuit 6, and a DC cancellation circuit 7. , digital quadrature demodulation circuit 8, carrier frequency error correction circuit 9, FFT calculation circuit 10, phase correction circuit 11, protection correlation / peak detection circuit 12, timing synchronization circuit 13, narrowband carrier error calculation circuit 14, broadband carrier error calculation circuit 15 , adding circuit 16 , numerically controlled oscillation (NCO) circuit 17 , frame synchronization circuit 18 , equa...

no. 2 example

[0339] Next, a second embodiment of the present invention is illustrated.

[0340] The OFDM receiver as the second embodiment of the present invention is designed similarly to the OFDM receiver 1 according to the foregoing first embodiment except that the symbol boundary calculation circuit is a modified form of the symbol boundary calculation circuit 43 . Thus, the OFDM receiver according to the second embodiment will be exemplified only with respect to the symbol boundary calculation circuit. The same or similar components as those in the first embodiment are denoted by the same or similar reference numerals in the drawings referred to in the description of the first embodiment, and will not be described again.

[0341] Figure 35 is a block diagram of a symbol boundary calculation circuit provided in the OFDM receiver as the second embodiment. The symbol boundary calculation circuit is denoted by reference numeral 65 .

[0342] Such as Figure 35 As shown in , the symbo...

no. 3 example

[0355] The third embodiment of the present invention is illustrated below.

[0356] Except that the guard correlation / peak detection circuit and the symbol boundary calculation circuit are respectively improved forms of the guard correlation / peak detection circuit 12 and the symbol boundary calculation circuit 43 in the first embodiment, the OFDM receiver as the third embodiment of the present invention Similar to the OFDM receiver 1 as the first embodiment. Thus, the OFDM receiver according to the third embodiment will be explained only with respect to the guard correlation / peak detection circuit and the symbol boundary calculation circuit. The same or similar components as those in the first embodiment are denoted by the same or similar reference numerals in the drawings referred to in the description of the first embodiment, and will not be described again.

[0357] Figure 37 is a block diagram of a guard correlation / peak detection circuit provided in an OFDM receiver as...

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Abstract

An OFDM demodulation ( 1 ) is provided which includes a guard correlation / peak time detection circuit ( 12 ) to generate a peak timing Np of a guard interval correlation value, and a timing synchronization circuit ( 13 ) to estimate a symbol-boundary time Nx from the peak timing Np. The timing synchronization circuit ( 13 ) calculates the symbol-boundary time Nx by filtering the peak time Np by a DLL (delay locked loop) filter ( 43 ). Further, the DLL filter ( 43 ) includes a limiter ( 52 ) to limit the range of phase-error component and an asymmetric gain circuit ( 53 ) to change the magnitude of the gain correspondingly to the polarity of the phase error to prevent the timing from being pulled out due to a fading or multipath.

Description

technical field [0001] The present invention relates to a demodulator for demodulating OFDM (Orthogonal Frequency Division Multiplexing) modulated signals. [0002] This application claims priority from Japanese Patent Application No. 2002-382212 filed on December 27, 2002, which is hereby incorporated by reference in its entirety Background technique [0003] For the transmission of digital signals there is a modulation technique known as "OFDM" (Orthogonal Frequency Division Multiplexing). OFDM technology is a technology that digitally modulates data for transmission by dividing the transmission frequency band into many orthogonal subcarriers, and using phase shift keying (PSK) and quadrature amplitude modulation to assign data to the amplitude and phase of each subcarrier. [0004] The OFDM technology is characterized in that since the transmission frequency band is divided into many sub-carriers, the frequency band of each sub-carrier is narrower, the modulation rate is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04J11/00H04L7/08H04L27/14H04L27/26
CPCH04L27/2676H04L27/2662H04L27/2657H04L27/2605
Inventor 舟本一久冈田隆宏池田保矢岛笃池田康成
Owner SONY CORP