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This paper introduces a one-bit digital radar involving direct one-bit sampling with unknown dithering of the received radio frequency (RF) signal. Due to avoiding the analog mixer and the down-conversion of the RF signal, the digital radar can be energy-efficient and low-priced. The use of unknown dithering allows for the one-bit samples to be processed efficiently using conventional algorithms. A computationally efficient range-Doppler estimation method based on fractional Fourier transform (FRFT) and fast Fourier transform (FFT) is used for linear frequency modulated continuous wave (LFMCW) transmissions, and the CLEAN algorithm is used for target parameter estimation.
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MTJ-Based Dithering for Stochastic Analog-to-Digital Conversion
The stochastic behavior of magnetic tunnel junctions (MTJ) finds use in many applications - from analog-to- digital conversion to neuromorphic computing. In this paper, a dithering method exploiting the stochastic behavior of an MTJ, based on the voltage controlled magnetic anisotropy effect, is proposed. This method is used to measure low frequency analog signals over an interval. The circuit is composed of two MTJ devices that convert an analog signal into a series of high resistance and low resistance stochastic states, creating a dithering effect. The behavior of the input signal is extracted from the switching frequency. The binary nature of the output signal reduces the complexity, enabling a small, fast, and energy efficient circuit for extracting different forms of information from an analog signal.
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- Award ID(s):
- 1716091
- PAR ID:
- 10293280
- Date Published:
- Journal Name:
- Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS)
- Page Range / eLocation ID:
- 1 to 5
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Probabilistic computing is a computing scheme that offers a more efficient approach than conventional complementary metal-oxide–semiconductor (CMOS)-based logic in a variety of applications ranging from optimization to Bayesian inference, and invertible Boolean logic. The probabilistic bit (or p-bit, the base unit of probabilistic computing) is a naturally fluctuating entity that requires tunable stochasticity; by coupling low-barrier stochastic magnetic tunnel junctions (MTJs) with a transistor circuit, a compact implementation is achieved. In this work, by combining stochastic MTJs with 2D-MoS2field-effect transistors (FETs), we demonstrate an on-chip realization of a p-bit building block displaying voltage-controllable stochasticity. Supported by circuit simulations, we analyze the three transistor-one magnetic tunnel junction (3T-1MTJ) p-bit design, evaluating how the characteristics of each component influence the overall p-bit output. While the current approach has not reached the level of maturity required to compete with CMOS-compatible MTJ technology, the design rules presented in this work are valuable for future experimental implementations of scaled on-chip p-bit networks with reduced footprint.more » « less
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null (Ed.)Similar to digital circuits, analog and mixed-signal (AMS) circuits are also susceptible to supply-chain attacks, such as piracy, overproduction, and Trojan insertion. However, unlike digital circuits, the supply-chain security of AMS circuits is less explored. In this work, we propose to perform "logic-locking" on the digital section of the AMS circuits. The idea is to make the analog design intentionally suffer from the effects of process variations, which impede the operation of the circuit. Only on applying the correct key, the effect of process variations are mitigated, and the analog circuit performs as desired. To this end, we render certain components in the analog circuit configurable. We propose an analysis to dictate which components need to be configurable to maximize the effect of an incorrect key. We conduct our analysis on the bandpass filter (BPF), low-noise amplifier (LNA), and low-dropout voltage regulator LDO) for both correct and incorrect keys to the locked optimizer. We also show experimental results for our technique on a BPF. We also analyze the effect of aging on our locking technique to ensure the reliability of the circuit with the correct key.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/ISCAS51556.2021.9401632
