As indicated in paragraph 3-3.3.1,
the tape deck is left running after the gain reference signal has been
recorded. It is important that the transition from this single frequency dwell
be made without changing any of the shaker system gains and without consuming
excessive tape time.
3-3.4.1 After recording the gain reference signal for one
minute, reduce the servo controller "set" level to minimum (less than 0.3g
peak) and reset the upper frequency limit of the sweep oscillator to 2000
3-3.4.2 With the upper sweep frequency limit at 2000 Hz,
readjust the servo controller "set" level to 1.09 (peak) and start the sweep
oscillator sweeping down.
3-3.4.3 When the sweep oscillator stops at 20 Hz, reduce
the servo level to minimum and stop the tape deck.
De-energize the shaker system. Record all significant data on the Tape Data
Sheet (Figure 3-3).
If the test laboratory has random test equipment, proceed to
4. If, however, no such capacity exists, the response tapes generated
shall be forwarded to the cognizant laboratory assigned the task to prepare
the synthetic random tape. When the tapes are prepared/returned, proceed to