Timing recovery apparatus and method for digital TV
AssigneeLG Electronics Inc.
InventorTae Won Lee
Life of this patent
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Abstract
A timing recovery apparatus and method for a digital TV is disclosed. The timing recovery apparatus includes: a symbol synchronization unit for determining the bandwidth of a timing recovery loop in a plurality of steps according to a convergence degree; and a timing lock detector for detecting a lock using a reference value calculated by the envelope of a timing error, whereby the envelope of the timing error calculated according to a channel state is used as a reference value for thereby preventing a lock error and assuring a rapid and accurate convergence characteristic.
Claims14
A timing recovery apparatus and method for a digital TV, comprising:
- a symbol synchronization unit for determining the bandwidth of a timing recovery loop in a plurality of steps according to a convergence degree to output a sampling frequency upon receipt of a baseband signal;
- and
- a timing lock detector for detecting the convergence state of the symbol synchronization unit and detecting a lock by using a reference value calculated by the envelope of a timing error.
A timing recovery method for a digital TV, wherein, if the timing recovery state is changed from the Pull-In state to the 2nd Lock-In state, the carrier recovery state is changed from Freeze to Blind 1, accordingly, if the timing recovery state is changed from the 2nd Lock-In state to the 2nd Lock-In state, the carrier recovery state is changed from Blind 1 to Blind 2, and accordingly, if the timing recovery state is changed from the 2nd Lock-In state to the Locked-In state, the carrier recovery state is changed to DD(decision direct).
A timing recovery method for a digital TV, comprising the steps of:
- detecting a timing error from a timing error detector upon receipt of a baseband signal;
- selecting a loop gain from a gain selector based on the detected timing error;
- outputting a reference value(REF+, REF−) from a timing error generated by each symbol;
- integrating a timing error by an interval integrator to output an integer value;
- comparing the reference value with the integer value to generate a lock/unlock count signal;
- perform counting to each threshold level upon receipt of the lock or unlock count signal, outputting the lock or unlock count signal, and resetting them by using a confidence counter;
- receiving the lock or unlock count signal from the confidence counter to output its state to a carrier synchronization unit, or receiving a carrier recovery state from the carrier synchronization unit to use the same in lock detection by using a lock controller;
- accumulating the detected error received from the gain selector to thus correct the same by using a loop filter;
- and
- outputting a sampling frequency according to a correction value.
Dependencies are inferred from the claim text.