The present invention provides a fractional-N frequency synthesizer comprising a divider controller comprising a multistage noise Shaping (MASH) digital delta-sigma modulator comprising L error feedback modulator (EFM) stages, wherein the jth EFM stage is configured to receive as an input the sum of the error of the preceding EFM stage and a high amplitude dither signal derived from the error of the kth EFM stage, where 1≤j≤k≤L.

The present invention provides a fractional-N frequency synthesizer comprising a divider controller comprising a multistage noise Shaping (MASH) digital delta-sigma modulator comprising L stages, wherein the jth stage is configured to receive as an input the sum of the error of the preceding stage and a high amplitude dither signal derived from the error of the kth stage, where 1≤j≤k≤L.

A multi-stage analog-to-digital converter includes a signal input terminal, a first stage analog-to-digital converter, a digital-to-analog converter; a second stage analog-to-digital converter, and dither circuitry. The first stage analog-to-digital converter includes an input coupled to the signal input terminal. The digital-to-analog converter includes an input coupled to an output of the first stage analog-to-digital converter, and an input coupled to the signal input terminal. The second stage analog-to-digital converter includes a first input coupled to an output of the digital-to-analog converter. The dither circuitry is coupled to a second input of the second stage analog-to-digital converter, and is configured to provide a dither signal to the second stage analog-to-digital converter during selection of fewer than all bits of a digital value of a residue signal received from the digital-to-analog converter.

A system and method of converting an analog input signal to a linearized digital representation of the analog input signal. A measure of the analog input signal is compared to a threshold associated with a maximum dynamic range of a quantizer. A maximum amplitude of a random, analog dither signal is dynamically varied for perturbing quantization of the analog input signal in response to the comparison. The dynamically varied dither signal and the analog input signal are combined to obtain a dithered input signal. The quantizer converts the dithered input signal into the linearized digital representation of the analog input signal.

A delta-sigma modulator (10) comprises a modulator loop (11) and a code generator (12). The modulator loop (11) comprises a loop filter (18). The code generator (12) is configured to generate a generator signal (BS) that is realized as an extended Barker code. The code generator (12) comprises a generator output (23) that is coupled to the loop filter (18).

A delta-sigma modulator (10) comprises a modulator loop (11) and a code generator (12). The modulator loop (11) comprises a loop filter (18). The code generator (12) is configured to generate a generator signal (BS) that is realized as an extended Barker code. The code generator (12) comprises a generator output (23) that is coupled to the loop filter (18).