Automatic calibration apparatus for telemetry systems

Apparatus automatically calibrates and tests spacecraft telemetry systems. The apparatus can generally be used to calibrate analog-to-digital converters

Time division multiplex system

Synchronizing apparatus for multi-access satellite time division multiplex syste

Stability analysis of automobile driver steering control

In steering an automobile, the driver must basically control the direction of the car's trajectory (heading angle) and the lateral deviation of the car relative to a delineated pathway. A previously published linear control model of driver steering behavior which is analyzed from a stability point of view is considered. A simple approximate expression for a stability parameter, phase margin, is derived in terms of various driver and vehicle control parameters, and boundaries for stability are discussed. A field test study is reviewed that includes the measurement of driver steering control parameters. Phase margins derived for a range of vehicle characteristics are found to be generally consistent with known adaptive properties of the human operator. The implications of these results are discussed in terms of driver adaptive behavior

Serrodyne frequency converter re-entrant amplifier system Patent

Serrodyne traveling wave tube reentrant amplifier for synchronous communication satellites operating at microwave frequencie

Resolving the discrepancy between X-ray and gravitational lensing mass measurements for clusters of galaxies

We present a detailed comparison of mass measurements for clusters of galaxies using ASCA and ROSAT X-ray data and constraints from strong and weak gravitational lensing. Our results for a sample of 13 clusters provide a consistent description of the distribution of gravitating matter in these systems. For the 6 cooling-flow clusters in the sample, which are the more dynamically-relaxed systems, the X-ray and strong gravitational lensing mass measurements show excellent agreement. The core radii for the mass distributions are small, with a mean value of ~ 50 $h_{50}^{-1}$ kpc. For the non-cooling flow clusters, the masses determined from the strong lensing data exceed the X-ray values by factors of $2-4$. However, significant offsets between the X-ray and lensing centres are observed, indicating that the X-ray and strong-lensing data are probing different lines of sight through the clusters. These offsets, and the generally complex dynamical states of the clusters inferred from their X-ray morphologies, lensing data and galaxy distributions, suggest that the gravitational potentials in the central regions of the non-cooling flow systems are evolving rapidly, and that the assumption of hydrostatic equilibrium involved in the X-ray mass measurements is likely to have broken down. The discrepancies between the X-ray and strong lensing mass measurements may be reconciled if the dynamical activity has caused the X-ray analyses to overestimate the core radii of the dominant mass clumps in these clusters. On larger spatial scales, comparisons of the X-ray mass results with measurements from weak gravitational lensing show excellent agreement for both cooling-flow and non-cooling flow clusters. (ABRIDGED)Comment: MNRAS in press. 18 pages including 4 figures in MNRAS LaTex styl

[Effect of Including Dielectronic Recombination Process in Calculating Ionization Equilibria for Oxygen]

Effect of including dielectronic recombination process in calculating ionization equilibria for oxyge

Welfare Reform: The View from New Hampshire and Massachusetts

As he promised during his election campaign, President Carter has proposed a major overhaul of the welfare system. Under the Better Jobs and Income Act, unveiled in August 1977, the major components of the current welfare system would be replaced by a program combining cash assistance and job opportunities. This paper evaluates the Carter proposal based on the experience under existing employment, training and welfare programs and then assesses its potential impact on the states of New Hampshire and Massachusetts. In the course of the discussion, we deal with the following questions: (1) Does the proposal effectively address the weaknesses in the current welfare system? (2) Can the proposal achieve its stated goals? (3) Will the impact of the program vary in states with different characteristics? (4) How do state administrators charged with implementing the program respond to its various components? Although the answers to these questions are seldom conclusive, the weight of the evidence leads us to conclude that there are serious weaknesses in the Carter proposal. Major changes are necessary in order for the program to become a viable alternative to the current system which both improves the status quo and achieves sufficient support to be enacted

Carrier extraction circuit

Feedback loop extracts demodulated reference signals from IF input and feeds signal back to demodulator. Since reference signal is extracted directly from carrier, no separate reference need be transmitted. Circuit obtains coherent carrier from balanced or unbalanced four-phase signal of varying characteristics