A wide-range high-linearity current-controlled pulse-width/ delay circuit suitable for current-mode controlled techniques is presented in this paper. The proposed circuit has been fabricated with 0.35µm CMOS 2P4M processes. The chip area is only 0.33mm × 0.12mm. The experimental results show the variation of the output frequency within ±0.2%, the tolerance of duty cycle is less than 0.2%. The current-controlled pulse-width/delay circuit is supply independent and can be operated at 2.5V. The linear range of input current is from 4µA to 277µA, and corresponding duty cycle of pulse-width output is from 1.59% to 97.2%. The experimental results agreed with the theoretical analysis are presented in this paper.
By combining a conventional single-ended RTD-based circuit called MOBILE with a transconductor using HEMTs, a fully-differential resonant-tunneling circuit is proposed. The circuit works as a clocked comparator, the sampling frequency of which is twice as high as the clock frequency. Our circuit simulation assuming 0.1-µm InP technology shows a 20-GHz sampling operation, which is suitable for GHz-range analog-to-digital converter applications.
This paper presents a work of utilizing multi-space random mapping (MRM) to formulate a dual-factor identification system, which combines speaker biometric and personal token. Our work has shown that MRM-system exhibits stronger discriminative ability when comparing test features to its counterfeit templates, which lied in other different random subspaces. This advantage thus contributes to better F-ratio and greater accuracy recognition.
A four-Current feedback operational amplifier (CFOA)-based state variable biquad is described which permits the accommodation of or compensation for the z-pin parasitic impedances of the CFOAsand offers a number of advantages over previously known CFOA-based biquad configurations. The workability of the circuit has been confirmed by SPICE simulation results based on commercially available AD844 type CFOAs.
A reciprocating optical modulator (ROM) generates a millimeter-wave signal in good efficiency. Internal bias modulation on a ROM is reported, in this paper. Owing to reciprocating modulation in the ROM, the driving voltage required for amplitude modulation on a millimeter-wave signal is highly decreased. In this paper, a millimeter-wave signal in the 52.8-GHz frequency band is amplitude-modulated with a low-voltage (2.0V) baseband signal, where half-wave voltage of the modulator embedded in the ROM is 6.4V.
A novel pulse-carving technique for an externally-modulated wideband frequency-shift-keying (FSK) format is proposed. Synchronous intensity modulation on the FSK signal suppresses undesired transient components generated during the bit transition time. Numerical analysis for the pulse-carving technique employing a Mach-Zehnder modulator driven by a sinusoidal signal indicates that the suppression of the components is typically more than 20dB.
An intermediate frequency (IF) linear-in-dB variable gain amplifier (VGA) for a radio receiver is fabricated in 0.15-µm fully-depleted (FD) SOI CMOS technology. The complete VGA consists of two stages of the modified linearized transconductance VGA, three stages of fixed gain amplifier (FGA) and a buffer. It provides a continuous -13.6dB to 55.8dB gain control range, an IIP3 of -13.55dBm and an NF of 13.3dB at 100MHz. The proposed VGA using FD SOI CMOS process has great advantages in power consumption and frequency response compared to the bulk CMOS VGA.
Cu gate metal oxide semiconductor (MOS) capacitors with and without thin chemical vapor deposition (CVD) TiSiN diffusion barrier were subjected to bias temperature stress (BTS) conditions. Cu drift flux for the MOS capacitor with CVD TiSiN diffusion barrier was about one order of magnitude smaller than that without the diffusion barrier. The activation energy of the drift flux was larger by a factor of 1.5 than that without the diffusion barrier. Cu thermal diffusion in the CVD TiSiN is dominant for Cu ion drift into the plasma enhanced (PE)-CVD SiO2. The Cu concentration depth profile in SiO2 showed that the Cu dose in PECVD SiO2 under thermal stress is significantly smaller than that under BTS conditions.