Minimal Energy Asynchronous Dynamic Adders

In battery-operated portable or implantable digital devices, where battery life needs to be maximized, it is necessary to minimize not only power consumption but also energy dissipation. Typical energy optimization measures include voltage reduction and operating at the slowest possible speed. We employ additional methods, including hybrid asynchronous dynamic design to enable operating over a wide range of battery voltage, aggregating large combinational logic blocks, and transistor sizing and reordering. We demonstrate the methods on simple adders, and discuss extension to other circuits. Three novel adders are proposed and analyzed: a 2-bit pass transistor logic (PTL) adder and two dynamic 2-bit adders. Circuit simulations on a 0.18-mum process at low voltage show that leakage energy is below 1%. The proposed adders achieve up to 40% energy savings relative to previously published results, while also operating faster     

A Solar Spectromagnetograph

A new solar spectromagnetograph for measuring the full magnetic-field vector and line-of-sight velocities is described. A new version of a polarization analyzer ensuring parallel measurements of six polarization components of spectral lines is considered. The spectromagnetograph allows the use of any algorithms for obtaining the magnetic fields vector, in particular, the Babcock algorithm and the Fourier transform technique. The sensitivity of the instrument for the longitudinal and transverse magnetic field is 3–5 and 20–30 G, respectively, and 10 m/s for the line-of-sight velocities.     

Second version of the IZMIRAN solar spectromagnetograph. Part I. Instrument design

The second version of the IZMIRAN solar spectromagnetograph (SM), which is designed for measuring the full vector of the magnetic field and the line-of-sight velocities in the solar photosphere, is described. In contrast to the conventional schemes, the described SM uses the parallel analysis of the spectrum and polarization of optical radiation. The latter could be performed thanks to the method of precise calibration of circuits with multielement photodetectors. The new scheme of the SM allows measurements of the Stokes parameters for two magnetically active lines with an accuracy limited by only the quantum noise of photodetectors.     

Second version of the IZMIRAN solar spectromagnetograph. Part II. Algorithms for preliminary data processing

A system of experiments and an algorithm for data processing that allow elimination of systematic errors, which are caused by instrument effects of the spectromagnetograph, are described. It is shown that the residual systematic error in measuring the Stokes parameters is approximately three times lower than the statistical errors related to quantum noise of receivers.