Conventional voltage-gain enhancement of a traditional cascode amplifier using a gate-driven amplifier is not suitably applicable in (very-) low supply voltages. Here, we propose a novel gain-enhancement technique called “body-driven gain-boosting” technique where a body-driven auxiliary amplifier enhances the output impedances of both the amplifier and the current-source load. Thus, the gain/swing requirement of the operational amplifier (opamp) is satisfied using a single-stage structure with much less power consumption compared to two- or multi-stage configurations. Simulation results of two different sub-1-V single-stage opamps for different speed-accuracy specifications are presented to demonstrate the effectiveness of the proposed structure.
A data hiding system in audio signals based on a Rational Dither Modulation is proposed, which hides information in the Modulated Complex Lapped Transform (MCLT) domain. The proposed system is able to hide around of 689bits per second, while keeping a CD-quality audio signal. Objective and subjective evaluations show robustness to classical attacks and transparency to the Human Auditory System (HAS), respectively. Comparison results, in similar conditions, with some other algorithms reported in the literature are also provided.
Terahertz (THz) technology is a focus of attention in research on applied optics. We have applied THz spectroscopy and THz-imaging method to text recognition of a medieval manuscript made from sheepskin. Based on the database which contains more than 200 spectra of art materials, the red ink on the manuscript was estimated as Cinnabar. The red ink text and stains on the text were successfully distinguished by the THz-Time Domain Spectroscopy (TDS) imaging with a component spatial pattern analysis. THz spectroscopy can be used as a non-invasive analysis method for conservation science of cultural properties.
A 5GHz differential power amplifier (PA) module with a dipole antenna has been implemented. The PA integrated circuit (IC) was mounted on a fluoroplastic substrate on which the dipole antenna was fabricated. The differential PA IC was fabricated using 0.18µm Si-CMOS process. For the differential operation, an n/nMOS push-pull circuit was employed. The PA IC was directly connected to the balance input of dipole antenna without a balun using stud bump bonding on a fluoroplastic substrate. The antenna was designed using a 3-dimensional electromagnetic simulator including a feed line. The measured gain of the PA module was 12.6dB at 5GHz.