Analog signal separator for UWB versus narrowband signals
View Patent ↗A system, method, and computer program product for removing “narrowband” interference from a broader spectrum containing a UWB signal, in a receiver of the UWB signal. The RFI is extracted from a broader spectrum to remove interference from the UWB signal, by employing an impulse response in a radio front-end of the UWB receiver that is matched with an incoming wavelet employed as part of a UWB signal to be received, matching the impulse response to the wavelet and its time-shifted and inverted versions, passing the wavelet unscathed through the receiver, and excising narrowband signals (continuous tones). Exemplary embodiments for the RFI extraction mechanism include a transmission line circuit, an active transmission line circuit, and an adaptable, controllable phase delay circuit.
1. An ultrawide bandwidth receiver, comprising:
an input terminal configured to receive an incoming signal including an ultrawide bandwidth signal and a narrowband signal that overlap in frequency;
an interference extraction circuit for receiving the incoming signal from the input terminal and providing an output signal to an extraction circuit output terminal, the interference extraction circuit being configured to have an impulse response including: a first component that has a first impulsive shape, and at least one other component delayed in time from the first component, and having a second impulsive shape;
an ultrawide bandwidth signal detector connected to the extraction circuit output terminal, and configured to detect the ultrawide bandwidth signal;
a splitter connected to the input terminal, and operating to split the incoming signal into at least a first split signal and a second split signal, the first split signal being provided to a first splitter output terminal, the second split signal being provided to a second splitter output terminal;
a delay element connected to the first splitter output terminal for delaying the first split signal by a delay time to provide a delayed signal at a delay output terminal; and
a combiner for combining the delayed signal and the second split signal to form the output signal,
wherein the interference extraction circuit allows energy from the ultrawide bandwidth signal to be conveyed to the extraction circuit output terminal and substantially blocks energy from the narrowband interference signal from being output to the extraction circuit output terminal.
2. An ultrawide bandwidth receiver, as recited in claim 1 , further comprising a controller configured to control operations of the ultrawide bandwidth signal detector and the interference extraction circuit.
3. An ultrawide bandwidth receiver, as recited in claim 1 , wherein the ultrawide bandwidth signal detector is a correlator.
4. An ultrawide bandwidth receiver, as recited in claim 1 , wherein the correlator is one of: a tracking correlator and an analog correlator.
5. An ultrawide bandwidth receiver, as recited in claim 1 , wherein the input terminal is connected to an antenna.
6. An ultrawide bandwidth receiver, as recited in claim 1 , wherein the interference extraction circuit further comprises an isolation device configured to couple the splitter to the combiner.
7. An ultrawide bandwidth receiver, as recited in claim 6 , wherein the isolation device is an inverting isolation device.
8. An ultrawide bandwidth receiver, as recited in claim 6 , wherein the isolation device includes an amplifier.
9. An ultrawide bandwidth receiver, as recited in claim 1 , wherein the second splitter output terminal is an inverting output terminal.
10. An ultrawide bandwidth receiver, as recited in claim 1 , wherein the delay element comprises a transmission line.
11. An ultrawide bandwidth receiver, as recited in claim 1 , wherein the delay element comprises one or mote series resistor element and at least one shunt capacitor element.
12. An ultrawide bandwidth receiver, as recited in claim 11 , wherein the at least one shunt capacitor element is electrically adjustable.
13. An ultrawide bandwidth receiver, as recited in claim 11 , wherein the at least one shunt capacitor element is a varactor.
14. An ultrawide bandwidth receiver, as recited in claim 1 , further comprising:
a monitoring mechanism configured to monitor at least one of a composite output level of the output signal; and
a controller configured to adjust delay time and determine a desired delay that results in the composite output level being a minimum.
15. An ultrawide bandwidth receiver, as recited in claim 14 , wherein the controller is configured to adjust the delay time across a range of possible delay times that corresponds with a bandwidth that contains the ultrawide bandwidth signal.
16. A radio frequency interference extraction mechanism for receiving an incoming ultrawide bandwidth signal and providing an adjusted ultrawide bandwidth signal that has any narrowband interference signal that coincides with the ultrawide bandwidth signal in frequency suppressed, comprising:
a radio front end, having an impulse response including a first impulse response component and a second impulse response component, for receiving the incoming ultrawide bandwidth signal and generating the adjusted ultrawide bandwidth signal;
a controller configured to control the radio front end to adjust a relative position of the first impulse response component and the second impulse response component; and
a control receiver configured to detect at least one of a signal energy level and a signal to noise ratio of the narrowband interference signal and to provide an indication to the controller regarding a characteristic feature of the narrowband interference signal,
wherein the radio front end comprises a plurality of adjustable-bias amplifiers connected in series for receiving the first impulse response component and generating the second impulse response component, and
wherein the controller is configured to set bias values in the adjustable-bias amplifiers.
17. A radio frequency interference extraction mechanism, as recited in claim 16 , wherein the controller further comprises a power sensor configured to determine a power level of the adjusted ultrawide bandwidth signal and inform the controller of the power level.
18. A radio frequency interference extraction mechanism, as recited in claim 16 , wherein the controller farther comprises:
a memory configured to hold a table of target biases corresponding to delays used by the controller when setting the bias values in the adjustable-bias amplifiers.
19. A radio frequency interference extraction mechanism, as recited in claim 16 , wherein one or more of the plurality of adjustable-bias amplifiers can be switchably bypassed, allowing a remaining set of the plurality of adjustable-bias amplifiers to generate the second impulse response component based on the first impulse response component.
20. A radio frequency interference extraction mechanism, as recited in claim 16 , further comprising a subtracting circuit configured to either subtract the second impulse response component from the first impulse response component, or to subtract the first impulse response component from the second impulse response component, in order to generate the adjusted ultrawide bandwidth signal.