System Test Data Research Articles

IMPATT-Diode Power Amplifiers for Digital Communication Systems

lMPATT-diode amplifiers with a power output of 1.0 W have been developed for use in an 11-GHz digital radio. Two types of amplifiers, a multistage reflection amplifier and a hybrid amplifier containing an injection-locked oscillator stage, have been evaluated by measuring the bit error rate degradation due to the amplifier. System test data show that the stable amplifier introduces little or no errors while the injection-locked oscillator (ILO) often introduces an error-rate floor.

Subsynchronous Resonance in Series Compensated Transmission Lines

The concept of subsynchronous resonance in series compensated transmission lines is presented. Contributions of synchronous generator rotor motion and induction generation to sustained subsynchronous oscillation are discussed. Computer simulation studies of a 500 kv transmission system are shown to closely correspond to actual system test data. Adverse effects of subsynchronous resonance on system components are described.

PROBLEMS IN EVALUATING SYSTEM MANNING REQUIREMENTS ESTIMATES AND ESTIMATION TECHNIQUES.

System manning requirements information is desired prior to the time when it is scheduled to become available under the Personnel Subsystem concept. Rather than proceed from the conclusion that a new manning estimation method is needed to obtain manning information earlier, it is assumed that present methods can be used. Support for the assumption was to be obtained by validating manning requirements estimates for several systems, and assessing the adequacy of the estimation methods. Problems that arose in conducting the study are discussed. The shortcomings of the Mace B and the Bomarc manning requirements analyses are discussed along with the inappropriateness of system test data as criteria against which to evaluate manning estimates. The human factors system analysis approach, modified to account for pertinent quantitative data, is recommended for estimating manning requirements during the initial stage of system development.

Environmental Problems with Acoustic- and Vibration-Measurement System Components

Missile rocket-engine noise- and vibration-measurement system components are subjected to severe environments which may introduce spurious signals in the data. Thus, all components and systems must be subjected to environmental tests prior to their use to assure good data quality. Such a program is described in this paper. Several types of commercial microphones. accelerometers, preamplifiers, and cables were subjected to environmental tests, and their outputs analyzed to determine effect upon data. In addition, an entire data-acquisition system (to recorder input), including mounting brackets, was subjected to vibration tests. The results are discussed in the following manner: (a) Test data are graphically presented. (b) Test results are analyzed to predict their effect on the data. (c) The results of the prediction are compared to measured missile data. (d) Individual components and system test data are compared to show differences in results. Both good and poor data taken from missile firings are also presented to show environmental effects.