Simplified High Frequency Tuner and Tuning Method
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Abstract
A disclosed method tunes a signal from a channelized spectrum having a predetermined channel spacing. A signal of interest having a predetermined maximum bandwidth is mixed with a local oscillator signal, which has a frequency that is an integer multiple of the channel spacing or one-half of a channel spacing displaced from an integer multiple of the channel spacing. The local oscillator signal is selected to frequency translate the signal of interest to within a near-baseband passband whose lower edge is spaced from DC by at least about the maximum bandwidth of the signal of interest. Problems associated with 1/f noise, DC offsets, and self-mixing products are avoided or substantially diminished. Other methods and systems are also disclosed.
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Citations
165 Claims
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1-125. -125. (canceled)
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126. A method for tuning a signal of interest from within a channelized spectrum, the method comprising:
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(a) splitting an incoming signal into two signal paths; (b) generating an approximately quadrature local oscillator signal from a local oscillator that is coarse-tunable across the channelized spectrum with a step size that is an integer multiple of the channel spacing; (c) quadrature mixing the split incoming signal with the local oscillator signal, thereby; (1) frequency translating to a near-baseband passband an upper high frequency spectrum of interest from above the frequency of the local oscillator signal and a lower high frequency spectrum of interest from below the frequency of the local oscillator signal, the near-baseband passband being defined with reference to a lower frequency F1 and an upper frequency F2, wherein F1=F2−
F1 and F1 is at least about the maximum bandwidth of the signal of interest; and(2) producing I and Q signals in approximate quadrature relation; (d) limiting the frequency spectrum of the I and Q signals, wherein spectrum coverage is provided of a selected one of the high frequency spectra of interest and analog processing of signals at or close to DC is avoided; and (e) repeating (a) through (d) in turn for a plurality of local oscillator frequencies, wherein high frequency spectra of interest tunable with the local oscillator frequencies of the plurality are interspersed among local oscillator frequencies of the plurality within the channelized spectrum. - View Dependent Claims (127, 128, 129, 130, 131)
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132-151. -151. (canceled)
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152. A method of tuning a signal of interest from a channelized spectrum, comprising:
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(a) receiving a signal of interest from a channelized spectrum having a predetermined channel spacing; (b) mixing the signal of interest with approximately phase-quadrature local oscillator signals, thereby creating I and Q signals; and (c) frequency translating the signal of interest to a near-baseband passband that is spaced from DC by about the passband width; (d) wherein the local oscillator signals have a frequency that is selected to dynamically track frequency movement of the signal of interest; (e) the signal of interest lies within one of an upper high frequency spectrum of interest and a lower high frequency spectrum of interest; and (f) the method further comprises providing spectrum coverage within one of the high frequency spectra of interest and not the other. - View Dependent Claims (153, 154, 155, 156, 157)
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158-163. -163. (canceled)
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164. A method of tuning a signal of interest having a predetermined bandwidth, comprising:
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(a) splitting an incoming signal into two signal paths; (b) generating an approximately quadrature local oscillator signal; (c) quadrature mixing the split incoming signal with the local oscillator signal, thereby frequency translating the signal of interest to within a near-baseband passband that (1) is spaced from DC by at least about the maximum bandwidth of the signal of interest, and (2) is about as wide as said maximum bandwidth; and (e) filtering the frequency translated signal of interest with a bandpass filter having a variable passband.
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165-166. -166. (canceled)
Specification