The stability of adiabatic stepwise charging reversible logic is discussed. In the case of adiabatic logic with asymmetric tank capacitors, we derive a matrix which connects the initial state and the final state after the charge-recycle process. From the analytical discussion, it is proved that the absolute value of the eigen value of the matrix is less than 1. Therefore, it is shown that a step waveform is spontaneously generated after many charge-recycle processes. Next, an adiabatic stepwise charging SRAM is proposed. The SRAM is immune to hot-carrier effects and electromigration even in the less-than-45-nm process, while it maintains an operating voltage of 1V or more. The SRAM is suitable for nanoscale circuits.
A concept of modulated scattering array antenna is proposed based on the modulated scattering technique. The array antenna consists of one antenna element and several modulated scattering elements (MSE). The configuration of the array antenna is very simple because only one branch of the front-end circuit is required. It is shown by experimental investigations that a 3-element modulated scattering array antenna composed of one λ/4 monopole and two λ/4 modulated scattering monopoles with λ/4 array spacing can provide diversity gain up to 8dB diversity gain at 0.1% of the cumulative distribution function in Rayleigh fading environment. The array antenna is suitable to the mobile handset applications where the space and the cost are strictly limited because of its simple configuration.
This paper presents a watermarking-based image quality evaluation method that estimates image quality in terms of classical objective metrics, such as PSNR, wPSNR, and Watson JND, without the need for original image. Considering the different frequency distribution of image, the watermark is embedded into the original image and its vulnerability is adjusted using automatic control. After processing, the degradation of the extracted watermark is used to estimate image quality in terms of the classical metrics. By comparing the image quality obtained by the proposed method with the calculated PSNR, wPSNR, and JND, it is clear that the proposed method can be used to evaluate image quality against JPEG compression with high accuracy.