Granted Patent B2

US 8,036,291 · App. 12/107,986 · Granted Oct 11, 2011

Abstract

Claims (48)

1. A method of fast fading channel Fast Fourier Transform (FFT) trigger point tracking in an integrated services digital broadcasting (ISDB) receiver, said method comprising:

inputting a signal in a fading channel comprising N Orthogonal Frequency Division Multiplexing (OFDM) symbols, wherein said N is a number;

determining an average correlation result of a current time-domain sample of said signal and a previous time-domain sample taken previously of said signal;

accumulating said average correlation result for at least one of said OFDM symbols;

determining a peak of said average correlation result to obtain a peak position;

identifying said peak position as a trigger point of said input signal; and

comparing said peak position with a first trigger point to generate a trigger point error signal,

wherein said first trigger point is set at the middle of a guard of at least one of said OFDM symbols to generate said trigger point error signal.

2. The method of claim 1 , wherein said ISDB receiver comprises an ISDB-T receiver.

3. The method of claim 1 , wherein said ISDB receiver comprises an ISDB-TSB receiver.

4. The method of claim 2 , further comprising scaling said trigger point error signal by a factor of 1/K, wherein said K is programmable.

5. The method of claim 4 , further comprising:

obtaining a second trigger point by adding said first trigger point with said scaled trigger point error signal; and

selecting said second trigger point as a correct trigger point of said input signal.

6. The method of claim 5 , further comprising adjusting said correct trigger point for every said N OFDM symbols.

7. The method of claim 1 , wherein said average correlation result comprises a moving average correlation result.

8. A non-transitory program storage device readable by computer, tangibly embodying a program of instructions executable by said computer to perform a method of fast fading channel Fast Fourier Transform (FFT) trigger point tracking in an integrated services digital broadcasting (ISDB) receiver, said method comprising:

inputting a signal in a fading channel comprising N Orthogonal Frequency Division Multiplexing (OFDM) symbols, wherein said N is a number;

determining an average correlation result of a current time-domain sample of said signal and a previous time-domain sample taken previously of said signal;

accumulating said average correlation result for at least one of said OFDM symbols;

determining a peak of said average correlation result to obtain a peak position;

identifying said peak position as a trigger point of said input signal; and

comparing said peak position with a first trigger point to generate a trigger point error signal,

wherein said first trigger point is set at the middle of a guard of at least one of said OFDM symbols to generate said trigger point error signal.

9. The program storage device of claim 8 , wherein said ISDB receiver comprises an ISDB-T receiver.

10. The program storage device of claim 8 , wherein said ISDB receiver comprises an ISDB-TSB receiver.

11. The program storage device of claim 9 , wherein said method further comprises scaling said trigger point error signal by a factor of 1/K, wherein said K is programmable.

12. The program storage device of claim 11 , wherein said method further comprises:

obtaining a second trigger point by adding said first trigger point with said scaled trigger point error signal; and

selecting said second trigger point as a correct trigger point of said input signal.

13. The program storage device of claim 12 , wherein said method further comprises adjusting said correct trigger point every said N OFDM symbols.

14. The program storage device of claim 8 , wherein said average correlation result comprises a moving average correlation result.

15. An apparatus for performing fast fading channel Fast Fourier Transform (FFT) trigger point tracking in an integrated services digital broadcasting (ISDB) receiver, wherein said apparatus comprises:

a memory unit comprising a set of computer programmable instructions;

a display unit operatively connected to said memory unit;

a processor that executes said computer programmable instructions and processes a signal in a fading channel comprising N Orthogonal Frequency Division Multiplexing (OFDM) symbols, wherein said N comprises a number;

a pair of moving average filters that determine an average correlation result of a current time-domain sample of said signal and a previous time-domain sample taken previously of said signal;

an accumulator that accumulates said average correlation result for at least one of said OFDM symbols; and

a peak detector that determines a peak of said average correlation result to obtain a peak position, and identifies said peak position as a trigger point of said input signal,

wherein said peak detector further compares said peak position with a first trigger point to generate a trigger point error signal, and

wherein said first trigger point is set at the middle of a guard of at least one of said OFDM symbols to generate said trigger point error signal.

16. The apparatus of claim 15 , wherein said ISDB receiver comprises an ISDB-T receiver.

17. The apparatus of claim 15 , wherein said ISDB receiver comprises an ISDB-TSB receiver.

18. The apparatus of claim 16 , wherein further comprising a scaling block that scales said trigger point error signal by a factor of 1/K, wherein said K is programmable.

19. The apparatus of claim 18 , further comprising:

a scaling block that obtains a second trigger point by adding said first trigger point with said scaled trigger point error signal; and

a trigger point peak detection block that selects said second trigger point as a correct trigger point of said input signal.

20. The apparatus of claim 19 , wherein said trigger point peak detection block adjusts said correct trigger point every said N OFDM symbols.

Assignments (23)