Patent ID: 8896471

Claim:
An apparatus for converting a discrete-time quantized signal into a continuous-time, continuously variable signal, comprising: an input line for accepting an input signal that is discrete in time and in value; a digital pre-distortion linearizing filter having an input coupled to the input line and Igin an output; a plurality of processing branches coupled to the output of the digital pre-distortion linearizing filter, each of said processing branches including: (a) a quantization circuit, (b) a multi-bit-to-variable-level signal converter coupled to an output of the quantization circuit, and (c) an analog bandpass filter coupled to an output of the multi-bit-to-continuously-variable signal converter; and an adder coupled to an output of the analog bandpass filter in each of the processing branches, wherein the analog bandpass filters in different ones of said processing branches select different frequency bands, and wherein the digital pre-distortion linearizing filter has a transfer function that produces an at least approximately all-pass response when convolved with a composite transfer function that represents the combined transfer functions of the analog bandpass filters in the processing branches.