scope:

This specification covers the general requirements for passive frequency-selective networks, such as dual functioning, band suppression, band pass, low pass, and high pass (or any combination thereof) electric-wave filters, including those employing electromechanical and piezoelectric elements, for use over the frequency range of 0 to 150 megahertz. Filters covered by this specification are intended for use where operation under various environmental conditions is required. This specification covers filters weighing not more than 50 pounds and requiring root-mean-square test voltage ratings not greater than 5,000 volts.

The type designation shall be in the following form, and as specified (see 3.1 and 6.1). The type designation does not describe a discrete item. For complete identification, the part number and type designation shall be referenced.

Filters are identified by the two-letter symbol "FR".

The grade is identified by a single digit in accordance with table I, denoting the type of enclosure and the vibration frequency level (see 4.7.13). TABLE I. Grade.

Symbol Type of enclosure Vibration frequency level ------------------------------------------------------- Hz 4 Metal-encased 10 - 55 5 Encapsulated 10 - 55 6 Metal-encased 10 - 2,000 7 Encapsulated 10 - 2,000 8 Metal-encased 10 - 500 9 Encapsulated 10 - 500

Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Naval Electronic Systems Command, ATTN: ELEX 8111, Department of the Navy, Washington, D.C. 20360 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter.

The class is identified by a single letter in accordance with table II, denoting the maximum operating temperature (see 6.6) for the realization of the life expectancy indicated in table II. TABLE II. Class.

Symbol Maximum operating temperature °C ------------------------------------------ P 65 Q 85 R 105 S 125 V Above 125

The life expectancy is identified by a single letter in accordance with table III. TABLE III. Life expectancy.

Symbol Life (hours, minimum) ------------------------------------ X 10,000 Y 2,500

The family is identified by a two-digit symbol in accordance with table IV.

The case and mounting dimensions are designated by a two-letter symbol in accordance with figures 1 to 6 inclusive.

Envelope dimensions for grades 5, 7, and 9 filters shall not exceed the maximum dimensions specified on figure 1, and the mounting dimensions shall be identical to the dimensions specified for the equivalent cased-filter size.

The composition of the filter is identified by a single-digit symbol denoting the principal resonators in accordance with table V. TABLE V. Composition.

Symbol Principal resonators ----------------------------------- 1 LC 2 Crystal 3 Other electromechanical