Patent ID: 8368763

Claim:
A method of identifying digital television transmissions, comprising: selecting a channel that is defined by a start frequency and a stop frequency; correlating a signal received over the channel to a reference digital television field sync signal that is transmitted over a field time period for a digital television broadcast signal, the field time period being an amount of time over which field sync data are transmitted; for each of a plurality of field time periods: determining, for a first window of data representing the signal received over a first portion of the field time period, a first non-coherent correlation power measure for the first window of data, the first non-coherent correlation power measure being determined based on the correlation of the first window of data to the reference digital television field sync signal; storing data representing the first non-coherent power measure in a delay register to create a delayed data sample; determining, for a second window of data representing signal received over a second portion of the field time period, a second non-coherent correlation power measure for the second window of data, the second non-coherent correlation power measure being determined based on the correlation of the second window of data to the reference digital television field sync signal; combining data representing the second non-coherent correlation power measure with the delayed data sample to create combined power data accumulating the combined power data over the plurality of field time periods; determining an energy estimate based on the accumulation of the combined power data; and generating a transmit mask filter based on the energy estimate.