A 23.3 dBm CMOS power amplifier with third-order gm cancellation linearization technique achieving OIP3 of 34 dBm

Purpose The purpose of this paper is to implement a highly linear 180 nm complementary metal oxide semiconductor (CMOS) power amplifier (PA) to meet the stringent linearity requirement of an long term evolution (LTE) signal with minimum trade-off to power added efficiency (PAE). Design/methodology/approach The CMOS PA is designed in a cascaded dual-stage configuration comprises a driver amplifier and a main PA. The gate voltage (VGS) of the driver amplifier is tuned to optimize its positive third-order transconductance (gm3) to be canceled with the main PA’s fixed negative gm3. The gm3 cancellation between these stages mitigates the third-order intermodulation product (IMD3) that contributes to enhanced linearity. Findings For driver’s VGS of 0.82 V with continuous wave signal, the proposed PA achieved a power gain of 14.5 dB with a peak PAE of 31.8% and a saturated output power of 23.3 dBm at 2.45 GHz. A maximum third-order output intercept point of 34 dBm is achieved at 20.2 dBm output power with a corresponding IMD3 of −33.4 dBc. When tested with a 20 MHz LTE signal, the PA delivers 19 dBm maximum linear output power for an adjacent channel leakage ratio specification of −30 dBc. Originality/value In this study, a novel cascaded gm3 cancellation technique has been implemented to achieve a maximum linear output power under modulated signals.

Low Probability of Intercept Triangular Modulated Frequency Modulated Continuous Wave Signal Characterization Comparison Using the Wigner Ville Distribution and the Choi Williams Distribution

Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time frequency analysis techniques for the purpose of analyzing low probability of intercept radar signals. This paper presents the novel approach of characterizing low probability of intercept triangular modulated frequency modulated continuous wave radar signals through utilization and direct comparison of the Wigner Ville Distribution versus the Choi Williams Distribution. The following metrics were used for evaluation: percent error of: carrier frequency, modulation bandwidth, modulation period, chirp rate, and time-frequency localization (x and y direction). Also used were: percent detection, lowest signal-to noise ratio for signal detection, and plot (processing) time. Experimental results demonstrate that overall, the Wigner Ville Distribution produced more accurate characterization metrics than the Choi Williams Distribution. An improvement in performance may well translate into an increase in personnel safety.

Adaptive wideband equalization for frequency dispersion correction in HF band considering variations in interference characteristics and ionosphere parameters

Paper presents the outcomes of the studies into the adaptive wideband equalization for frequency dispersion correction in HF band considering variations in interference characteristics and ionosphere parameters. The subject matter of the research were megahertz-bandwidth channels with single-hop F layer propagation mode. There are presented data on variations in the channel amplitude frequency response that are caused by the interference of magneto-ionic components (intramodal multipath). Test facility for carrying out full-scale experiments was developed with the use of Universal Software Radio Peripheral platform supported by the groundbreaking software-defined radio technology. Verification of the developed methods and algorithms was performed in the experiments on oblique sounding over the Cyprus-to-Yoshkar-Ola propagation path by the linearly frequency modulated continuous wave signal.

Asymmetric Data-Frequency Mapping and Multi Trigger-Probing for Improved Scan Debug

Integrated-circuit device dimensions continue to shrink, enabling higher density of devices and smaller node size. A number of strategies to improve the resolution of failure analysis and fault isolation tools exist, but some of these techniques are reaching fundamental limits so that engineers are also challenged to innovative methods to increase the useful life of existing toolsets. Laser Scanning Microscopy including Laser Voltage Probing and frequency mapping struggle to maintain resolution commensurate with shrinking feature size. Here we present two methods to improve efficiency and capability of this toolset using existing optical hardware and configuration. The first method applies a frequency mapping technique using scan chain data patterns that allow for data manipulation. This enables an effective resolution increase through deconvolution of data collected in a sequence of scans completed on varied device states. A second method using multiple triggers per loop to evaluate a deterministic continuous wave signal is shown to reduce probe acquisition time, improve job throughput time, and enable, better signal-to-noise ratio for common scan chain debug workflow.