arXiv subjects

Hemant Kumar Meena

Publications and source records attributed to Hemant Kumar Meena.

3 recordsLinked to original sources

arXiv2026

Design and Analysis of a Programmable Ramp Generator for Frequency Synthesizers

This paper presents a fully digital Programmable Ramp Generator (PRG) for reconfigurable frequency-ramp synthesizers used in Frequency-Modulated Continuous-Wave radar, spread-spectrum clock generation, and test and measurement applications. A novel modular architecture is proposed, integrating a phase-accumulator-based frequency sweep generator and Delta-Sigma Modulator (DSM) that drives a Multi-Modulus Divider (MMD), giving independent digital control over ramp slope, bandwidth, and duration. While prior works demonstrate chirp synthesis, the circuit-level constraints governing reliable PRG operation have not been jointly analyzed. This work identifies and analyzes three such constraints: (a) MMD octave-boundary behavior under dynamic updates, (b) divider-synchronous timing, and (c) DSM limits on step duration and achievable slope. Together, these constraints define the PRG design space, enabling a systematic algorithm that maps application-level specifications directly to hardware parameters. Following this methodology, a 16-bit PRG implemented in TSMC 65 nm CMOS is verified across 18 ramp profiles and hardware prototyping on a Xilinx Spartan-7 FPGA confirms real-time operation.

eess.SY↗

arXiv2025

Scalable Multisubject Vital Sign Monitoring With mmWave FMCW Radar and FPGA Prototyping

In this work, we introduce an innovative approach to estimate the vital signs of multiple human subjects simultaneously in a non-contact way using a Frequency Modulated Continuous Wave (FMCW) radar-based system. Traditional vital sign monitoring methods often face significant limitations, including subject discomfort with wearable devices, challenges in calibration, and the risk of infection transmission through contact measurement devices. To address these issues, this research is motivated by the need for versatile, non-contact vital monitoring solutions applicable in various critical scenarios. This work also explores the challenges of extending this capability to an arbitrary number of subjects, including hardware and theoretical limitations. Supported by rigorous experimental results and discussions, the paper illustrates the system's potential to redefine vital sign monitoring. An FPGA-based implementation is also presented as proof of concept for a hardware-based and portable solution, improving upon previous works by offering 2.7x faster execution and 18.4% less Look-Up Table (LUT) utilization, as well as providing over 7400x acceleration compared to its software counterpart.

eess.SY↗

arXiv2021

Controlled modulation of optical energy in the high order Hermite-Gaussian laser modes

The multiple lobes of high order Hermite-Gaussian (HG) laser modes differ in terms of shape, size, and optical energy distribution. Here, we introduce a generic numerical method that redistributes optical energy among the lobes of high order HG modes such that all the identical low intense lobes become both moderate or high intense lobes and vice-versa, in a controlled manner. Further, the modes which consist of only two types of intensity distribution among its multiple lobes are transformed together into all high intense lobes. Furthermore, in some cases, moderate intense lobes together with high intense lobes become high intense lobes, and moderate intense lobes together with low intense lobes become high intense lobes. Such controlled modulation of optical energy may offer efficient and selective utilization of each lobe of HG modes in most applications like particle manipulation, optical lithography, and the method can be used in other fields like nonlinear frequency conversion and shaping ultrafast optical pulses.

physics.optics↗