International Telemetering Conference Proceedings, Volume 06 (1970)http://hdl.handle.net/10150/5784362024-03-28T23:20:16Z2024-03-28T23:20:16ZInternational Telemetering Conference Proceedings, Volume 06 (1970)http://hdl.handle.net/10150/6665042022-10-30T01:07:16Z1970-10-01T00:00:00ZInternational Telemetering Conference Proceedings, Volume 06 (1970)
International Telemetering Conference Proceedings / October 13-15, 1970 / International Hotel, Los Angeles, California
1970-10-01T00:00:00ZQuartz Crystals Units for High G EnvironmentsBernstein, M.http://hdl.handle.net/10150/6069922020-04-02T11:40:07Z1970-10-01T00:00:00ZQuartz Crystals Units for High G Environments
Bernstein, M.
Quartz crystal units are commonly used to achieve frequency accuracy of the order of 100 parts per million or better. The usual crystal mechanical environments are quite benign compared with those encountered In high g telemetry, however, and the normal shock tests are only 100 g's. The preliminary, design of a ruggedized high frequency crystal unit is shown as well as test date on the behavior of these units when subjected to 15,000 g's of impact shock. A crystal resonator is quite fragile since at 20 MHz an AT resonator is only 3 thousandths of an inch in thickness. Higher frequency units appear to have a g limit only slightly in excess of 20,000 g's. At lower frequencies, the resonator is not the limiting element but the supports and bonds become unreliable. A trade-off must be made between a very stiff support, which will increase the acceptable g level, and the concomitant frequency instability due to changes in mechanical stress on the quartz resonator. These stress changes can be caused both by differential thermal expansion of the mount and quartz as well as by shock Induced effects.
International Telemetering Conference Proceedings / October 13-15, 1970 / International Hotel, Los Angeles, California
1970-10-01T00:00:00ZNotch Noise Loading Data on Baseband Tape RecordingHeideman, W. R.Nichols, M. H.http://hdl.handle.net/10150/6069892020-04-02T11:42:52Z1970-10-01T00:00:00ZNotch Noise Loading Data on Baseband Tape Recording
Heideman, W. R.; Nichols, M. H.
Notch power ratio tests were performed on a magnetic tape recorder/ reproducer, using direct recording in the baseband. For the equipment tested, it is concluded that the IRIG method of setting the record power level as that which produces 1% third harmonic on a single tone, does not necessarily result in an optimum record/reproduce cycle. It is concluded that the input and output levels should be set with reference to notch noise test data to optimize baseband tape recording performance for baseband recording of frequency division multiplexed systems. In order to interpret the notch noise data, it was necessary to assume two non-linear processes, one acting in conjunction with the record process and one in conjunction with the playback process.
International Telemetering Conference Proceedings / October 13-15, 1970 / International Hotel, Los Angeles, California
1970-10-01T00:00:00ZPerformance Evaluation Medthos for PCM Bit Synchronizer/Signal ConditionersPeavey, B.http://hdl.handle.net/10150/6069712020-04-02T11:43:16Z1970-10-01T00:00:00ZPerformance Evaluation Medthos for PCM Bit Synchronizer/Signal Conditioners
Peavey, B.
PCM Bit Synchronizer/Signal Conditioners (BSSC) possess 3 basic performance characteristics which directly affect the processing of PCM telemetry data. These characteristics are: bit error rate (BER), bit slippage rate (BSR), and bit sync acquisition (BSA). This paper describes proven methods to meaningfully, and accurately measure these characteristics with particular emphasis on BSR and BSA. These methods require relatively simple and inexpensive procedures and instrumentation, and could be used by manufacturers and users to evaluate and acceptance test BSSC. The basic principle employed in these methods is "fixed threshold frame synchronization" with a unique strategy. Thus, there is no requirement for bit delay between the reference and BSSC output data, and synchronization of the reference data in the comparator with the BSSC output data takes place automatically. Moreover, this approach to testing BSSC represents the actual situation in which the BSSC would be operating as part of the telemetry data system, and hence would provide a direct measure of system performance. In actual application, these methods proved to be very effective and accurate for input SNR of E(b) /N(0) > O dB, and slightly less accurate for E(b) /N(0) < O dB (data having more than 10% errors). In general, BSA and BSR measurement accuracies of 20-30 bits can be achieved. A detailed discussion of accuracy is presented in the paper. In addition, the BSR and BER measurement methods are applicable to assessing the performance of tape recorders (TR) as it affects the actual system performance, rather than just the peculiar TR characteristics of TBE (time base error), bit dropout, and wow and flutter.
International Telemetering Conference Proceedings / October 13-15, 1970 / International Hotel, Los Angeles, California
1970-10-01T00:00:00Z