Cognitive radio technique for efficiently receiving multiple signals using polyphase downconverter channelizers
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorSunil V. Ramlall
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Abstract
A system and method are disclosed for selecting a sampling frequency in a system that performs bandpass sampling and uses a polyphase downconverter channelizer to receive multiple RF signals. The method accounts for the frequency location of the received signals throughout the signal reception process to simplify the overall processing. The procedure finds a sampling frequency that positions all or a subset of the sampled signals such that the sampled signals fall within the input channels of the polyphase downconverter channelizer, thus simplifying processing compared to prior art methods which address the bandpass sampling and polyphase downconverter channelizer components separately.
Claims20
A system for receiving a plurality N of analog radio frequency signals, said system comprising:
- a bandpass-filtering component operable to bandpass filter the plurality N of analog radio frequency signals;
- an analog to digital converter operable to generate digitally sampled signals based on the bandpass-filtered plurality N of analog radio frequency signals;
- an M-path polyphase downcoverter channelizer operable to output converted intermediate frequency N signals based on the digitally sampled signals, respectively;
- a range-finding component operable to determine a minimum sample frequency range, [Fs,min1, Fs,min2], for sampling the bandpass-filtered plurality of analog radio frequency signals;
- and
- a frequency-setting component operable to determine a minimum sampling frequency, Fs, and to provide a sampling frequency instruction to said analog to digital converter,
- wherein Fs,min1 is the smallest sampling frequency that results in no aliasing of the N signals when bandpass sampling is performed,
- wherein Fs,min2 is larger than Fs,min1 and additionally results in no aliasing of the N signals when bandpass sampling is performed,
- wherein Fs,min1≤Fs≤Fs,min2,
- wherein said analog to digital converter is operable to sample the bandpass-filtered plurality N of analog radio frequency signals using the minimum sampling frequency, Fs, indicated in the sampling frequency instruction to generate digitally sampled signals, and
- wherein N is an integer greater than one.
A method of receiving a plurality N of analog radio frequency signals, said method comprising:
- bandpass filtering, via a bandpass-filtering component, the plurality N of analog radio frequency signals;
- generating, via an analog to digital converter, digitally sampled signals based on the bandpass-filtered plurality N of analog radio frequency signals;
- outputting, via an M-path polyphase downcoverter channelizer, converted intermediate frequency N signals based on the digitally sampled signals, respectively;
- determining, via a range-finding component, a minimum sample frequency range, [Fs,min1, Fs,min2], for sampling the bandpass-filtered plurality of analog radio frequency signals;
- determining, via a frequency-setting component, a minimum sampling frequency, Fs, and
- providing, via the frequency-setting component, a sampling frequency instruction to the analog to digital converter,
- wherein Fs,min1 is the smallest sampling frequency that results in no aliasing of the converted intermediate frequency N signals when bandpass sampling is performed,
- wherein Fs,min2 is larger than Fs,min1 and additionally results in no aliasing of the converted intermediate frequency N signals when bandpass sampling is performed,
- wherein Fs,min1≤Fs≤Fs,min2,
- wherein the analog to digital converter is operable to sample the bandpass-filtered plurality N of analog radio frequency signals using the minimum sampling frequency, Fs, indicated in the sampling frequency instruction to generate digitally sampled signals, and
- wherein N is an integer greater than one.
A non-transitory, tangible, computer-readable media having computer-readable instructions stored thereon, the computer-readable instructions being capable of being read by a computer and being capable of instructing the computer to perform a method of receiving a plurality N of analog radio frequency signals, said method comprising:
- bandpass filtering, via a bandpass-filtering component, the plurality N of analog radio frequency signals;
- generating, via an analog to digital converter, digitally sampled signals based on the bandpass-filtered plurality N of analog radio frequency signals;
- outputting, via an M-path polyphase downcoverter channelizer, converted intermediate frequency N signals based on the digitally sampled signals, respectively;
- determining, via a range-finding component, a minimum sample frequency range, [Fs,min1, Fs,min2], for sampling the bandpass-filtered plurality of analog radio frequency signals;
- determining, via a frequency-setting component, the minimum sampling frequency, Fs, and
- providing, via the frequency-setting component, a sampling frequency instruction to the analog to digital converter,
- wherein Fs,min1 is the smallest sampling frequency that results in no aliasing of the converted intermediate frequency N signals when bandpass sampling is performed,
- wherein Fs,min2 is larger than Fs,min1 and additionally results in no aliasing of the converted intermediate frequency N signals when bandpass sampling is performed,
- wherein Fs,min1≤Fs≤Fs,min2,
- wherein the analog to digital converter is operable to sample the bandpass-filtered plurality N of analog radio frequency signals using the minimum sampling frequency, Fs, indicated in the sampling frequency instruction to generate digitally sampled signals, and
- wherein N is an integer greater than one.
Dependencies are inferred from the claim text.