System and method for adaptive simultaneous transmit and receive leakage cancellation
First Claim
1. A method for leakage signal cancellation in a simultaneous transmit and receive RF system, the method comprising:
- generating a digital transmit signal;
delaying the digital transmit signal by a FIFO to control the number of delayed clock cycles of the digital transmit signal;
converting the delayed digital signal to an analog transmit signal and transmitting the analog transmit signal from the system;
receiving a receive signal produced by reflection of the analog transmit signal from an object or generated by a second RF system;
adaptively filtering the digital transmit signal by an adaptive finite input response (FIR) filter;
converting a digital output signal of the adaptive FIR filter to analog domain to generate an analog cancellation signal;
calculating filter coefficients for the adaptive FIR filter in real-time;
adaptively inputting the calculated filter coefficients to the adaptive FIR filter;
adding the analog cancellation signal to the receive signal to generate an analog error signal for cancelling leakage in the receive signal;
converting the analog error signal to a digital error signal; and
using the digital error signal to calculate the filter coefficients for the adaptive FIR filter in real-time.
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Abstract
Method and apparatus for leakage signal cancellation in a simultaneous transmit and receive RF system includes: generating a digital transmit signal for transmission from the system; receiving a receive signal produced by reflection of the transmit signal from an object or generated by a second RF system; adaptively filtering the transmit signal by an adaptive finite input response (FIR) filter; calculating filter coefficients for the adaptive FIR filter in real-time at a different sampling rate; adaptively inputting the calculated filter coefficients to the adaptive FIR filter to generate a cancellation signal in real-time; and applying the cancellation signal to the receive signal to cancel leakage in the receive signal to generate an optimum receive signal.
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Citations
15 Claims
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1. A method for leakage signal cancellation in a simultaneous transmit and receive RF system, the method comprising:
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generating a digital transmit signal; delaying the digital transmit signal by a FIFO to control the number of delayed clock cycles of the digital transmit signal; converting the delayed digital signal to an analog transmit signal and transmitting the analog transmit signal from the system; receiving a receive signal produced by reflection of the analog transmit signal from an object or generated by a second RF system; adaptively filtering the digital transmit signal by an adaptive finite input response (FIR) filter; converting a digital output signal of the adaptive FIR filter to analog domain to generate an analog cancellation signal; calculating filter coefficients for the adaptive FIR filter in real-time; adaptively inputting the calculated filter coefficients to the adaptive FIR filter; adding the analog cancellation signal to the receive signal to generate an analog error signal for cancelling leakage in the receive signal; converting the analog error signal to a digital error signal; and using the digital error signal to calculate the filter coefficients for the adaptive FIR filter in real-time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for leakage signal cancellation in a simultaneous transmit and receive RF system comprising:
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a digital waveform generator for generating a digital transmit signal; a FIFO for delaying the digital transmit signal to control the number of delayed clock cycles of the digital transmit signal; a first digital-to-analog converter (DAC) for converting the delayed digital signal to an analog transmit signal and transmitting the analog transmit signal from the system; a receiver for receiving a receive signal produced by reflection of the analog transmit signal from an object or generated by a second RF system; an adaptive finite input response (FIR) filter for adaptively filtering the digital transmit signal; a second digital-to-analog converter (DAC) for converting a digital output signal of the adaptive FIR filter to analog domain to generate an analog cancellation signal; a frequency domain adaptive filter (FDAF) circuit for calculating filter coefficients for the adaptive FIR filter in real-time and adaptively inputting the calculated filter coefficients to the FIR filter; an adder for adding the analog cancellation signal to the receive signal to generate an analog error signal for cancelling leakage in the receive; an analog-to-digital converter (ADC) for converting the analog error signal to a digital error signal; wherein the FDAF circuit uses the digital error signal to calculate the filter coefficients for the adaptive FIR filter in real-time. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification