Frequency modulation (FM) clear channel scanning system and method of using same

A computer readable medium embodied in a computer program for scanning frequency band signals received from an antenna comprising:

• an tuner operable to tune to two or more sub-bands within the band and operable to generate a tuned analog signal;
• an analog-to-digital converter (ADC) coupled to the tuner and operable to convert the tuned analog signal to a digital signal;
• an on-channel selection block responsive to the digital signal and operable to select only the on-channel frequencies and to substantially disregard the out-band channel frequencies from the digital signal and further operable to generate a figure of merit (FOM) on-channel signal representing a measurement of the signal quality of the on-channel signal;
• and
• an out-of-channel selection block responsive to the digital signal and operable to select only the out-of-channel frequencies and to substantially disregard the on-channel frequencies from the digital signal to operable to generate a FOM out-of-channel signal representing a measurement of the signal quality of the out-of-channel signal;
• and
• a finite state machine (FSM) responsive to the FOM on-channel signal and the FOM out-of-channel signal and operable to record the FOM from the on-channel selection block and the out-of-channel selection block, the FSM further operable to perform an initial sub-band scan by comparing the first FOM of each of the channels within the initial sub-band to determine a candidate channel based on the channel with the lowest FOM, the candidate channel used as a measure of comparison to other channels subsequently to maintain the “best” channel.

A method of scanning a band for a vacant channel comprising:

• a) receiving signals;
• b) tuning to sub-bands within the band;
• c) generating a tuned analog signal;
• d) converting the tuned analog signal to a digital signal;
• e) selecting only the on-channel frequencies and substantially disregarding the out-band channel frequencies from the digital signal to generate an on-channel signal;
• f) generating a figure of merit (FOM) on-channel signal;
• g) selecting only the out-of-channel frequencies and substantially disregarding the on-channel frequencies from the digital signal to generate a out-of-channel signal;
• and
• h) generating a FOM out-of-channel signal.

A scan system operative to receive signals of a band from an antenna and to convert the signals into digital signals comprising:

• tuning means for generating digital signals for two or more sub-bands within a band;
• means responsive to digital signals for selecting on-channel frequencies thereof and for substantially disregarding the out-of-channel frequencies thereof and for generating a figure of merit (FOM) on-channel signal representing a measurement of the signal quality of the on-channel signal;
• and
• means responsive to the digital signal for selecting only the out-of-channel frequencies thereof and to substantially disregard the on-channel frequencies thereof and for generating a FOM out-of-channel signal representing a measurement of the FOM of the out-of-channel signal,
• means for selecting a candidate channel within each of the sub-bands based on the on-channel and out-of-channel FOM signals and further for selecting the best channel among the candidate channels within the sub-bands as being a vacant channel.

A scan system operative to receive signals within a band from an antenna, the band including one or more sub-bands, comprising:

• finite state machine (FSM) operative to scan channels of each of the sub-bands and to determine the channel with the least figure of merit (FOM) in each of the sub-bands defined as the candidate channel;
• an on-channel selection block responsive to a digital signal and operable to select only the on-channel frequencies from each of the candidate channels and to substantially disregard out-of-channel frequencies from the digital signal and operative to generate a FOM on-channel signal representing a measurement of the signal quality of the on-channel signal;
• and
• an out-of-channel selection block responsive to the digital signal and operable to select only the out-of-channel frequencies and to substantially disregard the on-channel frequencies from the digital signal and operable to generate a FOM out-of-channel signal representing a measurement of the signal quality of the out-of-channel signal.