MIL-DTL-38449D
unit, except that there will be no output from pin 10. The input impedance at pin 10 shall exceed
10K ohms.
3.5.2 Reliability.
3.5.2.1 Signal pulse amplifier (all classes). The signal pulse amplifier section, which shall be
capable of sustaining the cyclic operating conditions specified herein without malfunction or
failure, shall have a minimum calculated mean-time-between-failures (MTBF) of 34,000 hours.
For purposes of this calculation, the failure rate data of MIL-HDBK-217 shall be used and a
component ambient temperature of 70°C shall be assumed.
3.5.2.2 Intercommunication amplifier (classes 3 and 4 only). The intercommunication amplifier
section shall have a minimum calculated MTBF of 25,000 hours when the calculation is
performed as specified in 3.5.2.1.
3.5.3 Maintainability. No adjustments or maintenance shall be required for the life of either
signal pulse or intercommunication amplifier sections.
3.6 Construction. The unit shall be hermetically sealed; all electrical components shall be solid-
state where applicable. No vacuum tubes shall be used. Unit construction shall preclude the
possibility of any parts working loose in service. The unit shall withstand the strains, jars,
vibrations, and other conditions incident to shipping, storage, installation, and service use.
3.6.1 Mounting. The unit shall be mountable in any position to a solid frame. Vibration
isolators or shock mounts shall not be used. Three AN117001 screws, oval fillister head,
0.164-32NC-2 (Phillips recess), or commercial equivalent, having a maximum head diameter of
0.27 inch, shall be used for mounting the unit to the airframe. Mounting holes shall be as shown
on Figure 1.
3.7 Performance. The amplifiers shall satisfy the following performance requirements:
3.7.1 Function. The unit shall meet the following requirements which shall be demonstrated by
tests herein, as required during the qualification testing. The pulse used throughout the functional
tests shall be typical of the output pulse of the induction coils. The induction coils necessary for
defining this pulse are in accordance with 3.7.2.
3.7.1.1 Input voltages. The unit shall sequence through each position as specified in Table I
over any supply voltage from 18.0 to 30.0V dc and with input signal characteristics described in
3.7.1.2, 3.7.1.3, 3.7.1.4, and B of Figure 2.
3.7.1.2 Signal sensitivity (advance). The unit shall advance one position from either READY to
CONTACT or from CONTACT to DISCONNECT when a minimum pulse amplitude of 7.5
volts is applied to pin F/6. This pulse shall be applied for not less than 3 milliseconds nor more
than 15 milliseconds. (See Figure 2.) The area defined as "May Operate" shall not be used for
system design considerations.
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