An automated multichannel solar radiometer has been designed and fabricated by the Atmospheric Remote Sensing Laboratory at The University of Arizona. The automated radiometer has 10 separate silicon-photodiodebased channels that allow near-simultaneous solar spectral measurements through narrow bandpass filters (approximately 10 nm) from the visible to near-IR regions. The photodiode detectors are temperature stabilized using a heating temperature controller circuit. The instrument is pointed toward the sun via an autotracking system that actively tracks the sun with a Ϯ0.05Њ tracking accuracy. The instrument can continuously collect data for about 22 h at once per minute sample rate. This paper presents instrument design features as well as some performance and experimental results for the automated solar radiometer.

A digital-electronic reconstruction system for MRI has been designed and demonstrated. The system is capable of reconstructing a 128 x 128 pixel image from complex-valued data in approximately 8 ms (122 frames per second) or a 256 x 256 pixel image in 32 ms (30 frames per second) using the standard 2D FFT reconstruction algorithm. Real-time MR imaging can be obtained when this reconstruction system is coupled with fast continuous echo-planar type data acquisition. This provides the unique potential for real-time monitoring of interventional procedures or for rapid patient positioning. The real-time reconstruction system presented here consists of four main subsystems: an analog to digital converter, an interface memory, the Fourier processor, and the display processor. The basic design of this reconstruction system is presented along with results, demonstrating the capability of the system.

7% paper describes the design and fabricm'on of a microprocessor controlled auto sun-tracking lkhannel solar radiometer system which is used in measuring the solar spectral irradiance received at the Earth's suface. The instrument measurements are employed in determining the atmospheric optical depths at 10 discrete wavelengths through visible and near IR regions. m e automated solar radiometer is capable of tracking the sun, and measuring and recording the output of 10 channels through the course of a day. Some pe formance and experimental results of the instrument are also presented in this paper.