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US07023929B2 Digital pre-compensation filter for DMT type transmitter 有权
DMT型变送器数字预补偿滤波器

Digital pre-compensation filter for DMT type transmitter
Abstract:
A method of providing an improved transfer function for a Discrete Multitone (DMT) type modulation transmitter with digital filtering after modulation followed by digital to analog converter and analog filtering is provided by sending a test signal to said transmitter and measuring the results of the test signal to determine the transfer function. The inverse of the transfer function that needs to be compensated is determined and the inverse of transfer function to be compensated is truncated to the region of interest (H2). The desired band split component of pre-compensation filter is designed (H3). The desired target frequency response of the pre-compensation filter is determined by H4=H2*H3 where H4 is the multiplication of H2 and H3 Given the target frequency response in H4 Hermetian symmetry is imposed on the frequency response. The inverse Fourier transform (IFFT) is taken to generate a time domain filter, h5. The characteristic of this filter is added at the digital filtering after modulation.
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