Patent ID: 6591091
Filing Date: 2003-07-08
Classification: H01F,H01L,H03B,H03D,H03F,H03G,H03H,H03J,H03L

Abstract:
A method of tuning a receiver that maintains a signal output from the receiver during the tuning process comprising:selecting a channel to be tuned; tuning the channel to approximately a desired first intermediate frequency by a first frequency source that is adjustable in coarse steps and having a wide bandwidth; filtering the channel at the desired first intermediate frequency in a bandpass filter having passband that is sufficiently wide to pass the channel and a portion of another channel; and tuning the channel at the first intermediate frequency to a second intermediate frequency by a second frequency source that is adjustable in fine steps and having a narrow bandwidth relative to the wide bandwidth of the first frequency source; wherein the tuning steps are performed in accordance with the following equation:FLO1âˆ’FSIGâˆ’(5/4*FLO2)=Fif, whereFLO1 is the frequency of the first frequency source, FLO2 is the frequency of the second frequency source, Fif is the second intermediate frequency, and FSIG is the frequency of the channel to be tuned.