Transceiver with isolation-filter compensation and method therefor
First Claim
1. A transceiver with isolation-filter compensation, said transceiver comprising:
- an RF transmitter configured to generate an RF transmit signal;
a first isolation filter having an input adapted to receive said RF transmit signal and to pass said RF transmit signal to an output of said first isolation filter;
an RF receiver configured to process an RF receive signal;
a second isolation filter having an input adapted to receive said RF receive signal and said RF transmit signal and having an output coupled to said RF receiver, said second isolation filter being configured to pass said RF receive signal from said input of said second isolation filter to said output of said second isolation filter and to leak a portion of said RF transmit signal at said output of said second isolation filter; and
a feedback control circuit coupled to said RF receiver, said feedback control circuit having a control input adapted to obtain said RF transmit signal from said first isolation filter, and said feedback control circuit being configured to compensate said RF receiver for said leaked portion of said RF transmit signal at said output of said second isolation filter in response to said RF transmit signal obtained from said first isolation filter.
1 Assignment
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Accused Products
Abstract
A transceiver (10) includes an RF transmitter (12) and an RF receiver (14) coupled together through a duplexer (30). An RF transmit signal (20) passes through the duplexer (30) from the transmitter (12) toward an antenna (18), and an RF receive signal (44) passes through the duplexer (30) from the antenna (18) toward the receiver (14). The duplexer (30) may leak significant portions (56, 58) of the transmit signal (20) into the receive signal (44), and the duplexer (30) may significantly distort the transmit signal (20). Such distortion is compensated in the transmitter (12) through the use of a linear predistorter (68) that is adjusted in response to an RF feedback signal obtained from the antenna-side of the duplexer (30) . Transmit signal leakage is compensated in the receiver (14) by producing a processed-cancellation signal (106) that, when combined with the receive signal (44) cancels the transmit signal portions (56, 58) leaked into the receive signal (44). The processed-cancellation signal (106) is generated by applying a transformation function to a raw-cancellation signal (122) obtained from the antenna-side of the duplexer (30).
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Citations
39 Claims
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1. A transceiver with isolation-filter compensation, said transceiver comprising:
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an RF transmitter configured to generate an RF transmit signal;
a first isolation filter having an input adapted to receive said RF transmit signal and to pass said RF transmit signal to an output of said first isolation filter;
an RF receiver configured to process an RF receive signal;
a second isolation filter having an input adapted to receive said RF receive signal and said RF transmit signal and having an output coupled to said RF receiver, said second isolation filter being configured to pass said RF receive signal from said input of said second isolation filter to said output of said second isolation filter and to leak a portion of said RF transmit signal at said output of said second isolation filter; and
a feedback control circuit coupled to said RF receiver, said feedback control circuit having a control input adapted to obtain said RF transmit signal from said first isolation filter, and said feedback control circuit being configured to compensate said RF receiver for said leaked portion of said RF transmit signal at said output of said second isolation filter in response to said RF transmit signal obtained from said first isolation filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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20. A transceiver with isolation-filter compensation, said transceiver comprising:
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an RF transmitter configured to generate an RF transmit signal;
a first isolation filter having an input adapted to receive said RF transmit signal and to distort said RF transmit signal while passing said RF transmit signal to an output of said first isolation filter;
an RF receiver configured to process an RF receive signal;
a second isolation filter having an input adapted pass said RF receive signal from said input of said second isolation filter to an output of said second isolation filter, said output of said second isolation filter being coupled to said RF receiver; and
a feedback control circuit coupled to said RF transmitter, said feedback control circuit having a control input adapted to obtain said RF transmit signal from said output of said first isolation filter, and said feedback control circuit being configured to control predistortion applied in said RF transmitter to compensate for distortion imparted to said RF transmit signal by said first isolation filter in response to said RF transmit signal obtained from said output of said first isolation filter. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method of operating an RF communications transceiver to compensate for leakage of an RF transmit signal into an RF receive signal, said method comprising:
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generating said RF transmit signal;
extracting a portion of said RF transmit signal to form a raw-cancellation signal;
applying a transformation function to-said raw-cancellation signal to-generate a processed-cancellation signal;
combining said processed-cancellation signal with said RF receive signal to form a leakage-compensated receive signal; and
adjusting said transformation function in response to said leakage-compensated receive signal. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39)
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Specification