Patent ID: 7616141
Filing Date: 2009-11-10
Classification: H03M

Abstract:
1. A lowpass sigma-delta digital-to-analog converter comprising: an interpolation filter for receiving an input and producing an output; a summing circuit for receiving the output of said interpolation filter and a feedback signal and producing an output; a loop filter receiving the output of said summing circuit as an input and producing an output; a truncator receiving the output of said loop filter and producing said feedback signal, an N-bit truncated digital signal, N being an integer with a value greater than one; a digital integrator receiving the output of said truncator as an input and producing an output; a randomizer block receiving the output of said digital integrator as an input and produce an output; a digital-to-analog converter receiving said output of said randomizer block as an input and producing an output; an analog differentiator receiving the output of said digital-to-analog converter as an input and producing an output; an analog post filter receiving the output of said analog differentiator and producing the output of said lowpass sigma-delta digital-to-analog converter.