Cambridge, Massachusetts

Analog Logic

Ben Vigoda

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Analog Logic

• Combine Efficiency of Analog Device Physics – 10-100x Less Power– 10x Less Area / Cost– Higher Performance

• With Scalability of Computing Digitally– Modular, Hierarchical for Automated Design Synthesis– Relatively Invariant to Fabrication Process

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From Digital Logic Gates to Analog Logic Gates

in out

0 1

1 0

Digital Inverter Probability Inverter

in, x out, y

Digital XOR

in out

Probabilistic XOR

Filtering and Control

Analog Logic: implement many statistical estimation and signal processing algorithms natively using analog “gates”

Compute probabilities for millions of variables at extremely high speed and with low power.

Demodulation, Equalization

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Test results from our first IC: Transfer Function of 2-Input SoftXOR Analog Logic Gate

Theory Measurement

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Analog Logic Receiver

• Front-end– Don’t spend energy amplifying interference

Eliminate Analog-to-Digital Converter (ADC)– Don’t convert interference into bits that we throw away later in base-band

Base-band– Analog Logic is 10x less power/area compared to digital implementations

Overall Analog Logic receiver– Same analog input and digital output as conventional receiver– Integrate ADC, processing, and gain throughout signal chain

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Wideband Front-end Acquisition and Tracking Circuit

• Analog Logic “Noise Lock Loop”: – Tx: Generate wideband waveforms – Rx: Amplify wide-band waveforms, while rejecting interference

• Applications in UWB, Radar, and GPS

• Synchronization of Pseudo-Random Signals by Forward-Only Message Passing with Application to Electronic Circuits. IEEE Transactions on Information Theory, August 2006. Vigoda, Gershenfeld, et al.