• Applicability of Implantable Telemetry Systems in Cardiovascular Research

      Krutz, Robert W.; Rader, R. D.; Meehan, John P.; Henry, James P.; USAF; University of Southern California (International Foundation for Telemetering, 1971-09)
      This paper briefly describes the results of an experimental program undertaken to develop and apply implanted telemetry to cardiovascular research. Because of the role the kidney may play in essential hypertension, emphasis is placed on telemetry's applicability in the study of renal physiology. Consequently, the relationship between pressure, flow, and hydraulic impedance are stressed. Results of an exercise study are given.
    • Computer Image Manipulation for Restoration and Enhancement

      Andrews, H. C.; University of Southern California (International Foundation for Telemetering, 1971-09)
      This paper briefly outlines a few ideas involved in the use of the versatility of high speed digital computers for natural photographic quality image restoration and enhancement. The subject of image digitization is briefly mentioned followed by three models for image restoration. The linear shift invariant (isoplanatic) model relies on a rich body of knowledge in the form of two dimensional linear systems theory. While the linear isoplanatic model is useful for a variety of degradating phenomena, the linear anisoplanatic and nonlinear models often provide further insight into specialized phenomena. Image restoration may often be followed by enhancement techniques which focus on image manipulations for presentation purposes. The psychophysics of vision play a major role in the development of this aspect as do heuristic techniques which tend to focus on known but often unexplainable human viewing responses. Examples from certain nonlinear enhancement processes are presented.
    • On the Timing Problem in Optical PPM Communications

      Gagliardi, R. M.; University of Southern California (International Foundation for Telemetering, 1971-09)
      The use of digital transmission with narrow light pulses appears attractive for data communications, but carries with it a stringent requirement on system bit timing. In this paper we investigate the effects of imperfect timing in a direct detection (noncoherent) optical system using PPM bits. Particular emphasis is placed on specification of timing accuracy, and an examination of system degradation when this accuracy is not attained. Bit error probabilities are shown as a function of timing errors, from which average error probabilities can be computed for specific synchronization methods. Of significant importance is the presence of a residual, or irreducible error probability, due entirely to the timing system, that cannot be overcome by the data channel.
    • A Real Time Programmable Data Compression System for Video Data

      Kutz, R. L.; Davisson, L. D.; NASA Goddard Spaceflight Center; University of Southern California (International Foundation for Telemetering, 1971-09)
      This paper describes the implementation of a data compression system for the real time operational transmission of advanced technology satellite (ATS) pictures between the command and data acquisition (CDA) station located at Wallops Island, Virginia and the National Environmental Satellite Service (NESS) at Suitland, Maryland over broadband microwave links. The system features the use of general purpose minicomputers for encoding and decoding which makes it possible to easily vary the data compression technique in use and to make simultaneous statistical calculations on the data. Special interfaces to the pre-existing equipment have been designed to insure efficient use of the parallel structure of the computers. Data compression and expansion is done in a way that results in no lowering of data quality.