Patent ID: 7113230

Claim:
Apparatus for deriving a channel map for a digital television (DTV) receiver comprising; a processor including a channel map data structure; a tuner, controlled by the processor to tune to a specified channel and provide a tuned television signal having an amplitude; a demodulator coupled to the tuner to demodulate the tuned television signal; an amplitude detector coupled directly to the tuner to provide a measure of the amplitude of the tuned television signal prior to the demodulation of the tuned television signal; and a comparator, configured to compare the measure of amplitude provided by the amplitude detector to a threshold value and to provide an output signal having a first value if the measure of amplitude is greater than the threshold value and having a second value otherwise; wherein the processor is responsive to the output signal of the comparator having the first value, to change a value in the channel map data structure to indicate that the specified channel is received by the DTV receiver.