| 摘要 |
Amplitudes of signals produced by a digital modulator can be clipped so that instead of processing the output vector of the digital modulator or it's component vectors, processing is applied to the base band I and Q signals prior to modulation. The I- and Q signals are applied to an input of a clipping circuit. Predetermined limit values are also applied to another input of the clipping circuit. The clipping circuit rotates on the I-Q vector towards the limit vector. At the same time the limit vector is rotated towards the I-Q vector. Rotations are performed by using Cordic algorithm. After rotations have been completed, the rotated I-Q vector is aligned with the original limit vector, and the rotated limit is aligned with the original I-Q vector. Then the length of the rotated I-Q vector will be compared with the original limit vector. If the rotated I-Q vector is shorter than the limit vector, then the original I-Q signals are output signals from the clipping circuit. But if the rotated original I-Q vector is longer than the limit vector, then the original I-Q signals will be rejected and substituted by the coordinate values of the rotated limit vector.
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