Patent ID: 6194942
Filing Date: 2001-02-27
Classification: H03F,H04B

Abstract:
A predistortion circuit, comprising:a first splitter for splitting an input signal into primary and secondary electrical paths;a first combiner connected to the first splitter via the primary electrical path for combining a main signal on the primary electrical path and a predistorted signal on the secondary electrical path into a single signal for modulating a nonlinear device with predictable distortion characteristics;a distortion signal generator disposed in the secondary electrical path and connected to the first splitter for receiving a branch signal from the first splitter and for producing first and second intermodulation products from the branch signal;a second splitter disposed in the secondary electrical path and connected to the distortion signal generator for receiving the first intermodulation products produced by the distortion signal generator and for outputting two sets of the first intermodulation products;a third splitter disposed in the secondary electrical path and connected to the distortion signal generator for receiving the second intermodulation products produced by the distortion signal generator and for outputting two sets of the second intermodulation products;an even-order signal processing unit disposed in the secondary electrical path for receiving and processing one of the sets of the first intermodulation products and one of the sets of the second intermodulation products to generate even-order intermodulation products;an odd-order signal processing unit disposed in the secondary electrical path for receiving and processing the other one of the sets of the first intermodulation products and the other one of the sets of the second intermodulation products to generate odd-order intermodulation products; anda second combiner disposed in the secondary electrical path and connected to the even-order signal processing unit, the odd-order signal processing unit and the first combiner for receiving and combining the even-order intermodulation products generated by the even-order signal processing unit and the odd-order intermodulation products generated by the odd-order signal processing unit to obtain the predistortion signal that is provided to the first combiner.