Hitachi, Ltd.

Tomoya Uchiike

Yoshiaki Hasegawa

Kazuyuki Hori

Yuji Ishida

Shouhei Murakami

Akihiro Saito

Yoshihiro Kanomata

A receiver of a wireless base station that uses a simple mode to detect a failure is provided, and an SWswitches whether an input port of the receiveris to be connected with an antennaor to be terminated. An LNA (a low noise amplifier)amplifies an input signal with a low distortion. SWsandswitch between a first path which runs through the LNAand a second pathwhich does not run through the LNA. An AGC AMP, the gain of which is controlled such that the output thereof is constant, amplifies the signal with the controlled gain. A base station control section uses the SWto terminate the input port of the receiver so that thermal noise is input to the LNA. Further, the SWsandare changed over to determine the normality of the receiver based on the fact that a first gain of an AGC-AMPwhen connected to the first path, a second gain of the AGC-AMPwhen connected to the second path, and a difference between the first and second gains fall within their respective predetermined ranges.

Base station, receiving apparatus, and receiver trouble diagnosing method

There is a need for effectively compensating distortion when a predistortion transmitter is subject to not only a memory effect due to nonlinearity of an amplifier, but also a modulator's DC offset, IQ unbalance, or local quadrature error. A predistortor to be used is a polynomial predistortor including a polynomial basis generation portion and an inner product calculation portion. The polynomial basis generation portion delays a real part and an imaginary part of a complex input signal Sx=Ix+jQx for up to M samples to generate 2(M+1) signals, duplicately combines these signals to generate monomials having maximum degree N, and outputs, as a basis vector, all or part of the monomials depending or needs. The inner product calculation portion performs an inner product calculation using a coefficient vector, i.e., a set of complex numbers sized equally to the basis vector to find a polynomial value and outputs the value as a complex signal.

Digital predistortion transmitter

Growing community of inventors

Fujisawa, Japan

Tomoya Uchiike