Downloaded from https://www.everyspec.com MIL-STD-81OC and +100, -50 percent (*3 dB) between 500 Hz and 2,000 Hz except that deviations as large as +3oo, -75 percent (i6 dB) shall be allowed over a cumulative bandwidth of 100 Hz maximum, between 500 and 2,000 Hz. Tolerance levels in terms of dB are defined as: dB = 10 loglo ~ Wo Where WI = measured accelerationpower spectral density in G2/HZ units. The.term W. defines the specified level in G2/Hz units. Confirmation of these tolerances shall be made by use of an analysis system providing statistical accuracies corresponding to a bandwidth-time constant product, BT = SO, minimum.
Specific analyzer characteristicsshal1 be as specified below or equivalent, subject to the BT = 50,minimum limitation. a. On-line, contiguous filter, equalization/analysissystem having a band- width as follows: B = 25 Hz, maximum between 20 and 200 Hz I B = 50 Hz, maximum between 200 and 1,000 Hz B = 100 Hz, maximum between 1,000 and 2,000 Hz b. Swept frequency analysis systems characterized as follows: (1) Constant bandwidth analyzer. (a) Filter bandwidth as follows:
B = 25 Hz, maximum between 20 to 200 Hz B = 50 Hz, maximum between 200 to 1,000 Hz B = 100 Hz, maximum between 1,000 to 2,000 Hz (b) Analyzer averaging time = T = 2 RC = 1 second, minimum, where T = True averaging time and RC = analyzer time constant (c) B2 Analysis sweep rate (linear) = R = ~ or ~ (Hz/second) maximum, whichever is smaller. 514.2-6 METHOD 514.2