0009 00 TM 1-6625-724-13&P 0009 00-6 Table 2. Frequency Ranges Vs. Respective Measurement Resolutions Frequency Normal Zoom Range Resolution Resolution 2 Hz to 100 Hz 0.25 Hz 0.016 Hz 2 Hz to 125 Hz 0.313 Hz 0.020 Hz 2 Hz to 200 Hz 0.50 Hz 0.0313 Hz 2 Hz to 250 Hz 0.625 Hz 0.039 Hz 2 Hz to 300 Hz 0.75 Hz 0.0469 Hz 2 Hz to 375 Hz 0.937 Hz 0.0586 Hz 2 Hz to 400 Hz 1.0 Hz 0.063 Hz 2 Hz to 500 Hz 1.25 Hz 0.078 Hz 2 Hz to 800 Hz 2.0 Hz 0.125 Hz 2 Hz to 1 kHz 2.5 Hz 0.156 Hz 2 Hz to 1.2 kHz 3.0 Hz 0.188 Hz 2 Hz to 1.5 kHz 3.75 Hz 0.234 Hz 2 Hz to 1.6 kHz 4.0 Hz 0.250 Hz 2 Hz to 2 kHz 5.0 Hz 0.313 Hz 2 Hz to 4 kHz 10.0 Hz 0.625 Hz 2 Hz to 5 kHz 12.5 Hz 0.781 Hz 2 Hz to 8 kHz 20.0 Hz 1.250 Hz 2 Hz to 10 kHz 25.0 Hz 1.563 Hz 2 Hz to 12 kHz 30.0 Hz 1.875 Hz 2 Hz to 15 kHz 37.5 Hz 2.344 Hz 2 Hz to 16 kHz 40.0 Hz 2.500 Hz 2 Hz to 20 kHz 50.0 Hz 3.126 Hz (3)  Synchronous Sampled Time Averaged Vibration Spectrum (SSTA) (Harmonic Spectrum): The vibration spectrum averages the corresponding samples from each revolution (rev-by-rev averaging), so that the non-harmonic components are progressively eliminated.  The sample rate is automatically adjusted to match the rotor frequency.  One hundred twenty eight spectral lines are computed from 1/4 R to 32 R in 1/4 R increments.  The AVA can measure four channels and track simultaneously using this measurement technique.  This measurement type is almost exclusively used for rotor track and balance.  The external tachometer can vary from 2.0 Hz to 485 Hz.  The setup in the aircraft configuration file determines the number of revs to average and acceptable frequency range.  In this case, there are two choices of data storage that can be made.  The first would be to store all 128 points of raw data collected for magnitude and phase (SSTA measurement mode).  The second would be to store only the first 12R components of raw data collected for magnitude and phase (SSTAR measurement mode).  Choosing to store the first 12 harmonic bins per R results in a decrease of disk space usage by ten times the amount needed for the SSTA measurement mode. (4)  Average Track and Lag: The average blade track and lag for each blade can be very accurately measured by the Universal Tracking Device (UTD), up to eight bladed rotor systems can be monitored and the average track and lag for each blade displayed within 1 mm.  The track/lag measurements can be made simultaneously with up to four vibration channels yielding highly correlated measurements quickly.  The aircraft configuration file contains aircraft-specific track setup information and determines the number of revolutions to collect and average into the track results. 7.    Fault Tolerance Features Measurements can be continued even if channel faults or filter faults occur during the measurement, causing acquisition failures for these channels.  The remaining good channels will be measured, and bad channel data will be marked as corrupted data.  Data received for the channels that were measured successfully will be stored, including both track and vibration data.  The availability of displays for the measured data should be used as indicators of data not retrieved, along with the error messages that appear on the screen during measurement.  The user will be informed of any such errors via the error report screen. END OF WORK PACKAGE