Combined RF peak suppression and pre-distortion circuit
OwnerKiomars Anvari, Michael Alan Parkerinventors
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Abstract
A technique for peak suppressing and pre-distorting the input signal to wireless amplifiers to improve the linearity of the amplifier and subsequently significantly improving the power efficiency of the amplifier is described. The input to the amplifier, prior to being applied to the amplifier, is modified by a peak suppression and pre-distortion circuit. The peak suppression and pre-distortion circuit uses samples of the output of the amplifier to adaptively adjust a lookup table that is being used for pre-distortion. The input and output of the peak suppression and pre-distortion circuit are at the amplifier frequency. The peak suppression and pre-distortion is performed in digital domain at baseband.
Claims14
A wireless peak suppression and pre-distortion circuit for use with power amplifiers in a wireless communication system to enhance the linearity and performance of the amplifier, in particular wireless cellular, PCS, wireless LAN, and satellite communication systems, the peak suppression and pre-distortion circuit comprising:
- Two receivers one for the peak suppression and pre-distortion main signal input and one for amplifier feedback input.
- A digital signal processing block to peak suppress and pre-distort the main input signal using a lookup table.
- A digital signal processing block to use the main input signal and amplifier feedback input to adaptively update the pre-distortion lookup table.
- A digital signal processing block to evaluate the delay between the main signal and the amplifier feedback signal and adjust the main signal delay before being used by the lookup table adaptation algorithm. The algorithm will continuously adjust the delay during the operation.
- A digital signal processing block to evaluate the gain between the main signal and the amplifier feedback signal and adjust the both signal's gain before being used by the lookup table adaptation algorithm. The algorithm will continuously adjust the gain during the operation.
- A digital signal processing block to accurately evaluate the delay between the main signal and the amplifier feedback signal by changing the coefficient of a decimation filter used in the path of amplifier feedback signal to produce T/256 accuracy.
- A transmitter block that prepare the peak suppressed and pre-distorted main signal for delivery to power amplifier.
Dependencies are inferred from the claim text.