High-contrast Imaging with Fizeau Interferometry: the Case of Altair*

The Large Binocular Telescope (LBT) has two 8.4 m primary mirrors that produce beams that can be combined coherently in a “Fizeau” interferometric mode. In principle, the Fizeau point-spread function (PSF) enables the probing of structure at a resolution up to three times better than that of the adaptive-optics-corrected PSF of a single 8.4 m telescope. In this work, we examined the nearby star Altair (5.13 pc, type A7V, hundreds of Myr to ≈1.4 Gyr) in the Fizeau mode with the LBT at Brα (4.05 μm) and carried out angular differential imaging to search for companions. This work presents the first filled-aperture LBT Fizeau science data set to benefit from a correcting mirror that provides active phase control. In the analysis of the λ/D angular regime, the sensitivity of the data set is down to ≈0.5 M ⊙ at 1″ for a 1.0 Gyr system. This sensitivity remains limited by the small amount of integration time, which is in turn limited by the instability of the Fizeau PSF. However, in the Fizeau fringe regime we attain sensitivities of Δm ≈ 5 at 0.″2 and put constraints on companions of 1.3 M ⊙ down to an inner angle of ≈0.″15, closer than any previously published direct imaging of Altair. This analysis is a pathfinder for future data sets of this type, and represents some of the first steps to unlocking the potential of the first Extremely Large Telescope. Fizeau observations will be able to reach dimmer targets with upgrades to the instrument, in particular the phase detector.

Light yield and field dependence measurement in PandaX-II dual-phase xenon detector

The dual-phase xenon time projection chamber (TPC) is one of the most sensitive detector technology for dark matter direct search, where the energy deposition of incoming particle can be converted into photons and electrons through xenon excitation and ionization. The detector response to signal energy deposition varies significantly with the electric field in liquid xenon. We study the detector's light yield and its dependence on the electric field in the PandaX-II dual-phase detector containing 580 kg liquid xenon in the sensitive volume. From our measurements, the light yield at electric fields from 0 V/cm to 317 V/cm is obtained for energy depositions up to 236 keV.

Design and Analysis of CMOS Phase Lock Loop (PLL) Using VLSI Technology

This paper proffers comparative research of Complementary MOSFET (CMOS) of the Phase Lock Loop (PPL) circuit. Our approach is based on hybrid design Phase Lock Loop (PLL) circuits combined in a single unit. A phase-locked loop (PLL) is used in space communication for synchronization purposes also very useful in time to digital converters and in instrumentation engineering. A phased lock loop (PLL) is a control system that makes an output signal whose frequency depends on the input phase difference. The phase detector takes the phase of an input signal and compares it with the phase procured from its output oscillator regulates the frequency of its oscillator to manage the phase matches. Different techniques like analogue and digital simulation with the help of mathematical/logical connections are found in Research to create the Phase Locked Loop (PLL). This limitation can be overcome by replicating the circuit block whose supply voltage is being reduced to manage the same throughout. This paper includes design features for low power phase-locked loop using Very-large-scale integration (VLSI) technology. The signal from the phase detector controls the oscillator in a feedback loop. As such: an operational device the PLL has a wide range of applications in computers sciences, telecommunication, and electronic system applications; we aim to design and examine the phase lock loop circuit in multiple technologies and examine their power capacity. By using the hybrid structure of NMOS and PMOS, here we have achieved the circuit of Phase Lock Loop (PLL) using VLSI technology. Keywords: Technology, CMOS, Phase lock loop, Micro wind, Voltage control oscillator, VLSI technology.

On digital phase detector

A digital phase detector for processing signals with phase modulation in a wide range of changes in the phase of the received signal is considered. A block diagram of a digital detector with minimal computational costs for the signal period is proposed. The problem of phase jumps when it changes by more than 2π is solved. An estimate is obtained for the noise immunity of a phase detector when exposed to Gaussian noise. Supposed hardware implementation of a phase detector based on field-programmable gate arrays. It can be used in devices for digital processing of the angular modulation signals, devices for controlling the phase of the reference signal and in different measurers.

Coherent demodulation of the two-level APSK signals with the symbol amplitude estimation

The study focuses on the algorithms for the coherent demodulation of the two-level amplitude phase-shift keyed signals with an estimate of the received symbol amplitude carried out by its relative comparison with the preceding symbol amplitude. Determining calibrated values of the symbol amplitudes in order to compare them with the preset threshold values is considered unnecessary in this case. Phase demodulation is implemented based on the phase detector of the multi-level phase-shift keyed signals. Symbol amplitudes are determined by the quadrature channels responses. Both analog and digital demodulation algorithms are considered. Simulation of the demodulation algorithm is carried out.

Analysis and Modeling of Mueller-Muller Clock and Data Recovery Circuits

In this paper, an accurate linear model of the Mueller-Muller phase detector (MMPD)-based clock and data recovery circuit (MM-CDR) is proposed, which analyzes several critical points of the MM-CDR including the linearization of the MMPD and the gain of the voter. Using our technique, the jitter between the recovery clock and the input data can be estimated with a sub-picosecond accuracy, as demonstrated in the simulation results of a 56 Gb/s quarter-rate MM-CDR implemented in 28 nm CMOS.