STADAR: Servo Tester with Automatic Data Acquisition and Reduction

STADAR is a Servo Tester with Automatic Data Acquisition and Reduction developed for the Apollo program. This paper describes the operational capability of STADAR and discusses certain aspects of the design. STADAR evaluates system performance by supplying an input stimuli and two data acquisition and analysis channels. Stimuli (0.02-30 c/s 0-10 V peak) are automatically programmed to a frequency accuracy of ±0.01 percent and an amplitude accuracy of ± 0.1 percent. Data acquisition accuracy is 0.1 percent or 50 microvolts. System design utilizes programmable data filters to improve system S/N ratio. Active filter mechanization methods and results are presented as well as techniques for instantaneous precise generation of stimuli which are automatically programmed.     

Scan conversion of radar images

The object of scan conversion is to resample a polar-sampled image into a Cartesian format while retaining integrity of the geometry and content of the image. Linear interpolation and decimation in two dimensions in the context of scan conversion are reviewed. Appropriate approximations of the nonlinear relationship between Cartesian and polar coordinates are then made to allow the application of the linear interpolation theory to produce a number of practical scan conversion algorithms. Together with an image prefiltering process, which is applied to areas which require scan conversion decimation, an effective scheme is presented