Efficient Dithering in MASH Sigma-Delta Modulators for Fractional Frequency Synthesizers

A Low Voltage Delta-Sigma Fractional Frequency Divider for Multi-band WSN Frequency Synthesizers

A 1 V low voltage delta-sigma fractional-N frequency divider for multi-band (780/868/915 MHz and 2.4 GHz) WSN frequency synthesizers is presented. The frequency divider consists of a dual-modulus prescaler, a pulse-swallow counter and a delta-sigma modulator. The high-speed and low-voltage phase-switching dualmodulus prescaler is used in the frequency divider. Low threshold voltage transistors ...

Time-Mode Signal Quantization for Use in Sigma-Delta Modulators

The rapid scaling in modern CMOS technology has motivated the researchers to design new analog-to-digital converter (ADC) architectures that can properly work in lower supply voltage. An exchanging the data quantization procedure from the amplitude to the time domain, can be a promising alternative well adapt with the technology scaling. This paper is going to review the recent development in t...

Effective-fourth-order resonator based MASH bandpass sigma-delta modulators

Two novel effective-fourth-order (eighth-order) resonator based MASH bandpass Σ−∆ modulators are introduced at the behavioural level and subsequently examined by simulations utilising the ALTA SPW environment. The considered bandpass configurations have in their loop filter a cascade of standard second-order resonator structures in order to achieve appropriate noise shaping. The quantisation no...

Self-Dithered Digital Delta-Sigma Modulators for Fractional-N PLL

Digital delta-sigma modulators (DDSMs) applied in fractional-N frequency synthesizers suffer from spurious tones which undermine the synthesizer’s spectral purity. We propose a solution featuring no hardware overhead while achieving equivalent spur elimination effect as using LFSR-dithering. This method can be implemented on MASH and single-loop DDSMs of 3rdand 2nd-order. key words: Digital del...

Multi-bit Delta-sigma Modulation Technique for Fractional-n Frequency Synthesizers by Woogeun Rhee