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International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / Multiple channel magnetic tape recording is often used for signal analysis of intelligence and telemetry data. To insure accuracy of the reproduced data, these systems require frequent calibration and alignment. As the number of tracks on these systems has increased, this task has become more time-consuming. Even with a well-trained technician, this task can take several hours at a minimum. To alleviate this problem, we developed a system for performing this calibration automatically. The implementation utilizes a Fast-Fourier-Transform technique to analyze the output of a pre-recorded signal on tape. The desired response, most frequently defined by IRIG Standards, is stored in a look-up table in the machine. The actual response is compared to that desired, and, under micro-processor control, adjustment made in the signal channel until an acceptable response is achieved. A unique photo-resistor technique is used in the signal path to control such parameters as gain and phase. A description of the hardware system will be given, as well as a description of the algorithms utilized for implementation.

International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / Multiple channel magnetic tape recording is often used for signal analysis of intelligence and telemetry data. To insure accuracy of the reproduced data, these systems require frequent calibration and alignment. As the number of tracks on these systems has increased, this task has become more time-consuming. Even with a well-trained technician, this task can take several hours at a minimum. To alleviate this problem, we developed a system for performing this calibration automatically. The implementation utilizes a Fast-Fourier-Transform technique to analyze the output of a pre-recorded signal on tape. The desired response, most frequently defined by IRIG Standards, is stored in a look-up table in the machine. The actual response is compared to that desired, and, under micro-processor control, adjustment made in the signal channel until an acceptable response is achieved. A unique photo-resistor technique is used in the signal path to control such parameters as gain and phase. A description of the hardware system will be given, as well as a description of the algorithms utilized for implementation.

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The technology of magnetic recording, which is involved in most aspects of modem life from credit cards to video tapes, is evolving at an ever quickening pace. As the industry strives to produce greater recording capacity and increased information density the demands on the development of improved magnetic storage and recording head materials cannot always keep up with the pace of change. The materials being considered are not only required to have the desired magnetic properties but also to have the necessary corrosion resistance in the operating environment. It is often the latter which can limit the rate of development of new devices since many of the new materials considered for magnetic storage applications consist of very reactive metals with low corrosion resistances. In establishing how research on the corrosion properties of new magnetic materials should be approached, two different experimental routes are explored in this thesis. These studies were a) a combined electrochemical and surface analysis study and b) a novel 'in-situ' SIMS study. The electrochemical study proved to be a very valuable route in obtaining information on the corrosion properties of the magnetically-active alloy FeMn and such a study can be highly recommended for the application to other magnetic materials. The complete electrochemical properties (anodic and cathodic) of FeMn were determined. A region of passivity was revealed through the application of the very sensitive solution analysis technique of ICPMS. The passive layer is associated with a manganese hydroxide rich surface layer. Passivity in the alloy is very vulnerable to corrosion attack by sodium sulphate active ions. The influence of temperature and pH was investigated. Only under low values of pH with the conditions investigated was the corrosion attack increased compared to neutral conditions. The application of sodium chromate inhibitor was found to enhance the passive layer formed. Using the second route the application of a novel 'in-situ' SIMS technique to look at the oxidation properties of magnetic metals and alloys was explored. The interpretation of the SIMS data for the oxidised and unoxidised components of cobalt was achieved and a model for the reaction of cobalt with oxygen at the initial stages of oxidation was successfully produced. At this present stage it is not possible to model the oxidation of more reactive metals than cobalt.

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International Telemetering Conference Proceedings / October 28-31, 1985 / Riviera Hotel, Las Vegas, Nevada / A novel source of noise is identified and described in this study. If a continuous recording medium is less than perfectly uniform, a given quantity may be recorded differently at different locations in the medium. Inadvertent “encoding” occurs, embedding noise in the signal. Symmetrical sideband noise power results from amplitude and phase modulation of the signal stream by the nonuniform recording medium. “Write noise”, so-called because writing is required, is correlated in amplitude with signal amplitude, and its mean frequency is the signal frequency. It is the dominant noise source for the current generation of recorders and tapes; its power spectrum is almost the same as the power spectrum of the signal. The ratio of standard deviation to mean value of the signal envelope when recording cw signals is an absolute measure of tape quality independent of record level, tape speed, and track width, and establishes an available signal-to-noise ratio which cannot be exceeded. It is assumed that the recorder output has a normal amplitude distribution about its mean value. Theory is confirmed by experiment, within experimental error, for cw and digital recording.

International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / In order to satisfy future instrumentation data recording requirements, the availability of high data rate recorders with long record times is most desirable. Also, assurance of commonality amongst the many users of these data requires that any system designed be compatible across the user data base. Hence, the American National Standards Institute (ANSI) has developed a tape format standard that will assure commonality and exchange of data in an acceptable manner. This standard also establishes data rate recording requirements using a commercially available media in cassette form that will satisfy the operational need. DATATAPE is developing a recorder system that will meet the ANSI requirements of the data format on tape, as well as the data rate and record times implied by the standard. This paper discusses the development of the tape format standard and the design of the system that will fully comply with the standard. Test data will be presented to verify system capabilities. Additionally, DATATAPE's progress in developing a system that will comply with the similar Department of Defense (DOD) tape format Standard, MIL-STD- 2179, will be presented, along with a summary of DOD programs that require MIL-STD-2179 compliant recorder systems.