This paper introduces and analyzes an ultra-low power and low-complexity analog IR-UWB radio system for unlicensed audio streaming which achieves continuous wave FM performance but exploiting aggressively duty-cycled signaling. At the TX, signal is modulated using a VCO which generates pulses with variable rate (PRF modulation), for an average of   $\sim$  600 kHz. At the RX an asynchronous and interference-robust detector regenerates the modulated signal at half frequency without requiring phase-locking, which is successively processed by a passive FM detector. The obtained demodulated signal is filtered using a fourth order Sallen-Key cell. The TX and RX modules based on commercial components draw 1.89 and 10 mA from 100 mAh Lithium-ion rechargeable batteries (1   $\times$   TX and 2   $\times$   RX) and include an integrated TX/RX chipset in a 130 nm RFCMOS technology which operates at 3.5 GHz center frequency and 1.2 V supply. The radio system transmits audio with THD   $  1%, provides an SNR of 64 dB (aligned with FM radio and compact cassettes) and has a frequency response 110 Hz–17 kHz, for a continuous play time of 50 h (TX) and 12 h (RX), and 2.5 m radio range.
['Marco Crepaldi', 'Matteo Stoppa', 'Paolo Motto Ros', 'Danilo Demarchi']
An Analog-Mode Impulse Radio System for Ultra-Low Power Short-Range Audio Streaming