Pulse or digital communications – Transmitters – Antinoise or distortion
Reexamination Certificate
2005-12-13
2005-12-13
Ha, Dac V. (Department: 2634)
Pulse or digital communications
Transmitters
Antinoise or distortion
C455S063300, C455S115200, C330S151000
Reexamination Certificate
active
06975688
ABSTRACT:
A method is disclosed for obtaining high throughput linearity using a pre-distorter in front of a RF power amplifier, for instance a multi-carrier power amplifier (MCPA) for a communications system. The method can be carried out off-line to thereby save costs and components otherwise needed for a common on-line feed back. In a first step calibration is performed by measuring by an off-line spectrum analysis an output spectrum of the power amplifier and simultaneously applying a known input signal. As a next step digitized parameters characterizing the power amplifier are calculated in the frequency domain by comparing spectrum points between input spectrum and output spectrum. Thereafter calculated and weighted digitized parameters are transferred to a pre-distorting device. In a third step the known signal spectrum is transferred to the pre-distorting device feeding its output signal together with the original known signal spectrum to the power amplifier input thereby compensating for power amplifier non-linearity and minimizing inter-modulation products. Finally in a fourth step an uncompensated known input spectrum is compared with a corresponding compensated output spectrum of the power amplifier and the steps of calibration calculation are repeated until a best optimization input signal to the power amplifier regarding the inter-modulation products of the output signal has been achieved.
REFERENCES:
patent: 5262734 (1993-11-01), Dent et al.
patent: 5732333 (1998-03-01), Cox et al.
patent: 5937011 (1999-08-01), Carney et al.
patent: 5959499 (1999-09-01), Khan et al.
patent: 6304140 (2001-10-01), Thron et al.
patent: WO 00/01065 (2000-01-01), None
Johansson Bernt
Rexberg Leonard
Ha Dac V.
Telefonaktiebolaget LM Ericsson (publ)
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