Digitally assisted multi-Bit ΣΔ modulator

A 1-V 1.1-MHz BW digitally assisted multi-bit multi-rate hybrid CT ΣΔ with 78-dB SFDR

Compensation of Nonlinearities in ΣΔ Modulators Using Digital Assisted Analog Electronics Approach

This paper presents a Digital Signal Processing (DSP) technique to compensate nonlinearities in reconfigurable Sigma Delta (ΣΔ) Modulator. In order to design digitally enhanced transceiver, a problem of nonlinearities in these modulators should be addressed. The problem arises due to the constituent building block of ΣΔ Modulators i.e. Digital to Analog Converter (DAC). Since DAC is outside the...

Chip Design of a Low-Voltage Wideband Continuous-Time Sigma-Delta Modulator with DWA Technology for WiMAX Applications

This paper presents the design and experimental results of a continuous-time (CT) sigma-delta (ΣΔ) modulator with data-weighted average (DWA) technology for WiMAX applications. The proposed modulator comprises a third-order active RC loop filter, internal quantizer operating at 160 MHz and three DAC circuits. A multi-bit quantizer is used to increase resolution and multi-bit non-return-to-zero ...

CMOS Bit-Stream Band-Pass Beamforming

We introduce a unique bandpass ΣΔ based common module with reconfigurable, bit-stream based digital beam-forming (DBF). An array of bandpass ΣΔ modulators accurately and efficiently digitizes the IF signals. Beam-forming is implemented directly through bitsteam processing of the fast, low-resolution bit-stream outputs of the quantizers of each bandpass ΣΔ modulator. Fabricated in 65nm CMOS, the...

DAC Topologies for GSM ΣΔ Modulators

Multi-bit ΣΔ modulators have become the preferred option for high performance, low power cellular GSM applications. When using multi-bit quantization, modulator performance becomes extremely sensitive to the internal digital-to-analog converter (DAC) non-linearity. DAC designs must fulfill linearity, power, and speed requirements for GSM while at the same time enabling dynamic element matching ...