| 摘要 |
This invention relates to a nonlinear distortion compensating circuit in which a digital value expressing the amplitude of an input signal is divided into upper and lower bits, only the upper bits are input to an address in a first memory, a value obtained by adding 1 to the upper bits is input to an address in a second memory, or, an interpolation circuit to which the upper bits are input inputs the upper bits to a first memory storing data corresponding to an even-numbered address and a second memory storing data corresponding to an odd-numbered address, and performs interpolation by adding outputs from the first and second memories by weighting these outputs in accordance with a value expressed by the lower bits, and the input signal is multiplied by the obtained value. In this arrangement, an interpolation circuit output based on the outputs from the first and second memories is an orthogonal coordinate expression (a combination of a real part and imaginary part) or a polar coordinate expression (a combination of an amplitude and phase).
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