This paper presents a novel ASK demodulation technique, using an Event-Based ADC (EB-ADC) and a digital ASK demodulation algorithm. The EB-ADC employs a minimalist Level Crossing Sample Scheme (LCSS) with only 2 levels, and uses a Time-to-Digital Converter (TDC) for measuring the time elapsed between two consecutive level crossings (events). The level crossing detection modules are composed of two strong-arm comparators. These comparators were characterized through an electrical simulation and then modeled in SystemVerilog in order to be integrated in a full digital simulation environment. The RF input signal of the testbench and its noise model have been modeled by replicating python's awgn function of commpy library. This demodulation technique takes advantage of the time measurement elapsed between two adjacent events, to apply a digital demodulation algorithm, for improving the symbol recognition performance and the noise resiliency, reaching for example a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{BER}=3.33\cdot 10^{-7}$</tex> with a modulation index of 10%, a bit rate of 6.78 Mbps and a SNR of 16 dB. A circuit implementing this approach is currently in fabrication in FDSOI 28nm STMicroelectronics technology. 

A Novel Event-Based Method for ASK Demodulation

This paper presents a comparison between two ASK demodulation techniques. The first one is a digital implementation of a traditional IQ demodulation, while the second is a novel digital demodulation algorithm connected to an EB-ADC (Event-Based ADC) for minimizing the number of processed events. The EB-ADC has been designed using a reduced LCSS (Level Crossing Sample Scheme) with only 2 levels, connected to two strong-arm comparators for the digitalization process. Electrical simulations were used to characterize these comparators for integrating them in a full digital SystemVerilog (SV) simulation. An adaptation of python’s library has been modeled in SV for simulating the RF input signal and its amplitude noise. This implemented algorithm benefits from the measurement of the time elapsed between two adjacent events improving the demodulator performance and noise resiliency, reaching, for instance, a BER=$3.33\cdot 10^{-7}$ for a modulation index (MI) of 10%, a SNR of 16 dB and a bitrate of 6.78 Mbps. This proposal was recently sent to fabrication in FDSOI 28nm STMicroelectronics technology.

Comparison between an ASK Event-Based Demodulation and a Digital IQ Demodulation

Over the years, several clock and data recovery architectures have been proposed for wireless Amplitude Shift Keying (ASK) transmitted signals. State-of-the-art architectures mainly rely on synchronous phase-locked loop circuits or self- sampling systems, both resulting in large area consumption. This work presents a novel CMOS architecture for Clock and Data Recovery (CDR) in miniaturised and wirelessly powered implants. The proposed CDR architecture works at 433.92 MHz and includes: an ASK-demodulator, an on-chip oscillator, a power-on-reset, a control and a recovering block operating in feedback-loop. The ASK-demodulator works for a data rate as high as 6 Mbps and a modulation index in the range of 9-30%. A novel communication protocol is presented for a separated clock and data transmission. The entire CDR architecture occupies $17 \times 89 \mu m^{2}$ and consumes $15.01 \mu W$ while operating with a clock rate of 6 Mbps.

An Ultra-Miniaturised CMOS Clock and Data Recovery System for Wireless ASK Transmission

This paper presents the proof of concept of an almost full digital ASK demodulation technique, targeting the usage of advanced technology nodes, and hence reducing power consumption and area. High level Matlab simulations validate the functionality of the demodulator. The whole structure of this method uses two hysteresis comparators, one custom voltage level generator, two logical gates, a small delay block and a register. This technique allows the ASK demodulation with a minimum modulation index (MI) of 3%, a SNR of 28 dB and a bitrate of fc/4. When using higher MI values, the method is more sensitive and resistant to noise, reaching for example a BER = 0.15%, with a MI = 30%, and a SNR = 13 dB.

An Event-Based Strategy for ASK demodulation

This paper presents a novel ASK demodulation technique, using an Event-Based ADC (EB-ADC) and a digital ASK demodulation algorithm. The EB-ADC employs a minimalist Level Crossing Sample Scheme (LCSS) with only 2 levels, and uses a Time-to-Digital Converter (TDC) for measuring the time elapsed between two consecutive level crossings (events). The level crossing detection modules are composed of two strong-arm comparators. These comparators were characterized through an electrical simulation and then modeled in SystemVerilog in order to be integrated in a full digital simulation environment. The RF input signal of the testbench and its noise model have been modeled by replicating python's awgn function of commpy library. This demodulation technique takes advantage of the time measurement elapsed between two adjacent events, to apply a digital demodulation algorithm, for improving the symbol recognition performance and the noise resiliency, reaching for example a $\text{BER}=3.33\cdot 10^{-7}$ with a modulation index of 10%, a bit rate of 6.78 Mbps and a SNR of 16 dB. A circuit implementing this approach is currently in fabrication in FDSOI 28nm STMicroelectronics technology.

This paper presents a full digital ASK demodulation technique, targeting the usage of advanced technology nodes. Matlab simulations validate the functionality of the demodulator. The whole structure of this method uses two hysteresis comparators, one custom voltage level generator, two logical gates, a small delay block and a register. This technique allows a minimum modulation index of 3%, a SNR of 28 dB and a bitrate of fc/4. When using higher MI values, the method is more sensitive and resistant to noise, reaching for example a BER = 0.15%, with a MI = 30% and a SNR = 13 dB.

Alexis Rodrigo Iga Jadue

Papers

An Event-Based Strategy for ASK demodulation

A Novel Event-Based Method for ASK Demodulation

Comparison between an ASK Event-Based Demodulation and a Digital IQ Demodulation

A Digital Event-Based Strategy for ASK demodulation