RFDAC Transmitter Using Multiphase Image Select FIR DAC and Delta Sigma Modulator with Multiple Rx Band NTF Zeros

Abstract

A transmitter includes a delta-sigma modulator characterized by a noise transfer function having a multitude of zeroes positioned substantially near a frequency band of a receive signal. The transmitter further includes, in part, a multi-phase digital-to-analog (DAC) converter converting an output signal of the delta-sigma modulator to an analog signal. The DAC is characterized by a transfer function that passes the desired signal to its output and attenuates a multitude of images of the sampling clock signal. The transmitter transmits at a frequency defined by an odd multiple of a fraction of the sampling clock signal frequency. The DAC includes a number of stages each pair of which is associated with one of the images being attenuated. The delta-sigma modulator includes a multitude of stages each associated with a different one of the zeroes. Each stage of said delta-sigma modulator optionally receives three tap coefficients.

Dependencies are inferred from the claim text.