An ADPLL-Based GFSK Modulator with Two-Point Modulation for IoT Applications.
Sensors (Basel)
; 24(16)2024 Aug 14.
Article
en En
| MEDLINE
| ID: mdl-39204950
ABSTRACT
To establish ubiquitous and energy-efficient wireless sensor networks (WSNs), short-range Internet of Things (IoT) devices require Bluetooth low energy (BLE) technology, which functions at 2.4 GHz. This study presents a novel approach as follows a fully integrated all-digital phase-locked loop (ADPLL)-based Gaussian frequency shift keying (GFSK) modulator incorporating two-point modulation (TPM). The modulator aims to enhance the efficiency of BLE communication in these networks. The design includes a time-to-digital converter (TDC) with the following three key features to improve linearity and time resolution fast settling time, low dropout regulators (LDOs) that adapt to process, voltage, and temperature (PVT) variations, and interpolation assisted by an analog-to-digital converter (ADC). It features a digital controlled oscillator (DCO) with two key enhancements as follows ΔΣ modulator dithering and hierarchical capacitive banks, which expand the frequency tuning range and improve linearity, and an integrated, fast-converging least-mean-square (LMS) algorithm for DCO gain calibration, which ensures compliance with BLE 5.0 stable modulation index (SMI) requirements. Implemented in a 28 nm CMOS process, occupying an active area of 0.33 mm2, the modulator demonstrates a wide frequency tuning range of from 2.21 to 2.58 GHz, in-band phase noise of -102.1 dBc/Hz, and FSK error of 1.42% while consuming 1.6 mW.
Bluetooth low energy (BLE); Gaussian frequency shift keying (GFSK); Internet of Things (IoT); all-digital phase-locked loop (ADPLL); digitally controlled oscillator (DCO); frequency shift keying (FSK) error; frequency tuning range; least mean square (LMS) algorithm; low dropout regulator (LDO); phase noise; process, voltage, and temperature (PVT) variations; stable modulation index (SMI); time-to-digital converter (TDC); two-point modulation (TPM); wireless sensor networks (WSNs)
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Sensors (Basel)
Año:
2024
Tipo del documento:
Article