Telecommunications – Receiver or analog modulated signal frequency converter – Noise or interference elimination
Reexamination Certificate
2007-02-27
2007-02-27
Nguyen, Tony T. (Department: 2618)
Telecommunications
Receiver or analog modulated signal frequency converter
Noise or interference elimination
C455S067130, C455S115400, C330S109000, C375S219000
Reexamination Certificate
active
10394981
ABSTRACT:
In a communications receiver for quadrature demodulation, a feedback technique for reducing the image response of the receiver. The communications receiver includes an I demodulator and a Q demodulator. A local oscillator (LO) signal is provided by a PLL to a quadrature LO generator that provides an LO_I signal to an I demodulator and an LO_Q signal to a Q demodulator. The LO_I and LO_Q signals are amplitude and phase-controlled versions of the LO signal. An image/signal ratio (I/S) detector detects the relative phase difference and the relative amplitude difference between the respective output terminals of the I demodulator and the Q demodulator and applies an amplitude control signal and a phase control signal to corresponding amplitude control and phase control inputs of the quadrature LO generator. The I/S detector calibrates the quadrature LO generator during the interstitial interval between the reception of data packets. The control signals from the I/S detector adjust the relative amplitude and phase of the LO_I and LO_Q signals in a manner that reduces the image response of the communications receiver.
REFERENCES:
patent: 4723318 (1988-02-01), Marshall
patent: 5469126 (1995-11-01), Murtojarvi
patent: 5715529 (1998-02-01), Kianush et al.
patent: 5784402 (1998-07-01), Feber
patent: 5812823 (1998-09-01), Kahle et al.
patent: 5894496 (1999-04-01), Jones
patent: 5926646 (1999-07-01), Pickett et al.
patent: 5974306 (1999-10-01), Hornak et al.
patent: 5983082 (1999-11-01), Hibert
patent: 6016422 (2000-01-01), Bartusiak
patent: 6035186 (2000-03-01), Moore et al.
patent: 6061711 (2000-05-01), Song et al.
patent: 6377315 (2002-04-01), Carr et al.
patent: 6697345 (2004-02-01), Corrigan et al.
Specification of the Bluetooth System—Core;v1.0B; Dec. 1, 1999; pp. 1-1082.
Intel, iAPX 86, 88, 186 and 188 User's Manual—Programmer's Reference; 1985; Cover Page and pp. 3-1-3-6.
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