Purchase_Description_15E-186A-RF_Step_Attenuator_Rev6.pdf

15E-186A-RF

29 November 2014

Rev 6

PURCHASE DESCRIPTION

FOR Step Attenuator

1. SCOPE

This Purchase Description (PD) describes a Step Attenuator capable of calibrating parameters required for TACAN Test Sets 2 tone modulation, Selective Level Meter, RADAR Test Sets, and Ramp Test Sets. The following will discuss the minimum performance, design, environmental, reliability requirements, and quality assurance provisions for this Step Attenuator.

2. PERFORMANCE REQUIREMENTS

The Step Attenuator must meet or exceed the following measurements uncertainties with a 95% confidence level.

2.1. Frequency range: DC to 1.5 GHz

2.2. Attenuation range: 0 to 50 dB

2.3. Resolution: 0.1 dB, 1 dB and 10 dB steps

2.4. Attenuation Accuracy: 0.1 to 0.9 dB +/-0.1 dB, 1.0 to 50 dB +/-0.2 dB.

2.5. Repeatability: +/-0.02 dB

2.6. Impedance: 50 Ohms

2.7. Insertion Loss: </=1.5 dB

2.8. Maximum Power: 1 Watt

3. MECHANICAL & PHYSICAL REQUIREMENTS

3.1. Connectors: N-Type female connections

3.2. Dimensions: The Step Attenuator shall be capable of fitting into a standard 19 inch rack width and be less than 8 inches tall. Weight shall not exceed 50 lbs.

4. FIRMWARE

When a firmware or software upgrade is anticipated by a manufacturer during the life cycle of this contract, the contractor shall contact AFMETCAL for concurrence. If AFMETCAL concurs with the proposed upgrade all previous units shall be updated to this upgrade. All firmware or software provided under this contract shall be of the same version, revision, and revision date at the completion of the contract.

5. GENERAL REQUIREMENTS

5.1. Functional: All attenuation settings shall be viewable and controllable through front panel

5.2. Safety: Protection shall be provided from, but not limited to, safety hazards as specified herein.

5.2.1. Accessible Potentials: Operating and maintenance personnel shall be protected from hazardous potentials by shielding, marking, or other suitable measures. Parts of equipment which become accessible upon removing a cover, opening a door, adjusting a control, setting a supply circuit voltage mechanism, replacing a fuse, attaching and detaching an interconnecting cable assembly, etc. and are intended for access by the operator during normal use shall not render an electric shock.

5.2.2. Grounding: During operation of the fully assembled test equipment, all electrically conductive external surfaces except trim and identification plates shall be at earth ground potential. Ground connection shall be of sufficient mechanical strength to minimize the possibility of ground disconnection. Such ground path shall have sufficiently low impedance and ample capacity to conduct safely any operating or fault currents imposed on it.

5.2.3. Thermal Hazards: Protection shall be provided from equipment temperatures which could constitute a hazard to personnel.

5.2.4. Mechanical Hazards: Suitable protection shall be provided to prevent contact with moving mechanical parts when the equipment is complete and operating.

Sharp projections on enclosures shall be avoided.

5.3. Parts, Materials, and Processes: Parts, materials, and processes associated with the equipment shall meet the following requirements.

5.3.1. Coaxial Cable Electrical Insulation: Materials used in electronic cable and connector technology shall be selected such that they degrade by a mechanism other than elimination and shall be resistant to corrosion and reductions in performance.

5.3.2. Commercial Parts: Commercial parts and materials that are used shall have properties consistent with a precision laboratory instrument.

5.3.3. Selected Components: Matched and selected components as well as specially built, nonstandard components shall not be used.

5.3.4. Metals: Metals shall be of the corrosion-resistant type or shall be metallurgically processed or suitably treated to resist corrosion due to atmospheric conditions likely to be met in storage, service, and/or transportation. Dissimilar metals in close contact with each other shall not be present.

5.3.5. Design and Construction: The equipment shall be designed and constructed of materials that meet the requirements of this specification and in accordance with the best commercial practices for industry approved equipment. It shall be designed and manufactured to achieve reliability, maintainability, accuracy of operation, and ease of operation. All parts such as shafts, bearings, regulators, switches, controls, etc., shall have proper clearance and adjustments. They shall work together so that the equipment will supply the rated requirements without unnecessary strains, vibrations, or overheating. They shall be able to withstand the conditions met in shipping, storage, installation, and service. All material and parts of this equipment shall be capable of withstanding the environmental requirements of this specification.

5.4. Electrical Power Sources and Connections:

5.4.1. Power Requirements: The equipment shall operate within the specified performance and accuracy requirements under nominal power conditions of either commercial, military, and/or shipboard single-phase power sources of 110 volts (rms) or 220 volts (rms) plus or minus 10%, at 50 and 60 Hz plus or minus 5% single phase input power.

5.4.2. Input Power Switch: There shall be an input power on / off switch located on the front panel of the equipment.

5.4.3. Fuses or Circuit Breakers: Fuses or circuit breakers shall be provided to automatically disconnect the equipment from the source in the event of excessive current drain. If circuit breakers are used, both sides of the power source shall be automatically disconnected from the equipment in the event of excessive current. If fuses are used, only the high side of the input power line shall be fused. Fuses and circuit breakers shall be readily accessible.

5.4.4. Indicators: Visual indication shall be provided on the front panel of the equipment to indicate when the equipment is energized.

5.4.5. Polarization: The polarization of all cable connectors shall be accomplished by a mechanical or visual method that prevents inadvertent mating in more than one position.

5.4.6. Plug-in Cabling: All plug-in cabling shall be capable of being connected and disconnected without disassembly or removal of adjacent components.

5.5. Enclosure: The STEP ATTENUATOR shall have an enclosure. The enclosure shall be constructed of aluminum, plastic, or fiberglass. The enclosure shall provide protection from mechanical shock and conditions associated with bench-top use and shall have no openings on the top surface.

5.6. Equipment Identification: The STEP ATTENUATOR shall be assigned a model number designation by the manufacturer. Each production unit shall be assigned a unique serial number designation by the manufacturer. The STEP ATTENUATOR shall follow the Item Identification and Valuation clause as stated in the contract. The information specified below shall be identified on the STEP ATTENUATOR.

5.6.1. Manufacturer name

5.6.2. Equipment name

5.6.3. Equipment model number (including options, if any)

5.6.4. Equipment serial number

5.7. Warm-Up, Continuous Operation, Environmental Requirements.

5.7.1. Warm-Up Period: After a warm-up period not to exceed 90 minutes, the STEP

ATTENUATOR shall meet all specifications contained in this PD unless otherwise specified.

5.7.2. Continuous Operation: After the required warm-up period, the STEP ATTENUATOR shall meet all specifications of this purchase description and shall not display any intermittent characteristics or overheating for an extended period of not less than 8 hours of continuous operation.

5.7.3. Operating Temperature Range: The STEP ATTENUATOR shall meet the specified performance and accuracy requirements over the operating temperature range of 73 ± 6 degrees Fahrenheit.

5.7.4. Operating Relative Humidity Range: The STEP ATTENUATOR shall meet the specified performance and accuracy requirements over the operating relative humidity range of 20 to 50%.

5.7.5. Non-operating Storage Temperature: The STEP ATTENUATOR shall meet specified performance and accuracy requirements after being stored at temperatures ranging from 15 to 140 degrees Fahrenheit (-9 to 60 Celsius).

5.8. Accessories: All accessories necessary for normal operation of the STEP ATTENUATOR shall be supplied, not necessarily limited to the following: power cords (detachable, at least 6 feet in length), GPIB cables (IEEE STD 488.1 1987, at least 6 feet in length), equipment cases/covers, adapters.

5.9. Metric Products: Products manufactured to metric dimensions will be considered on an equal basis with those manufactured using inch/pound units, provided they fall within the specified tolerances using conversion tables contained in the latest revision of Federal Standard No. 376, and all other requirements of this purchase description are met.

6. TESTING REQUIREMENTS

The STEP ATTENUATOR shall be inspected and accepted at destination as specified elsewhere in the contract. The item will be checked with test equipment whose parameters are equal to or better than those required to ensure specified performance requirements are met. Test equipment used, where required, has first echelon certification directly traceable to the National Institute of Standards and Technology, NMI or other AFMETCAL approved equivalent laboratory. Tests will be performed to ensure the STEP ATTENUATOR meets the requirements of this purchase description, OEM commercial manuals, and/or any AFPSL check standards with documented historical data deemed appropriate by the government.

Such testing at destination does not relieve the contractor of performing all inspections and quality checks at the point of fabrication, as specified elsewhere in the contract, or as necessary, to ensure performance as specified herein.

Attachment:

Data Requirements

Attachment to Purchase Description 15E-186A-RF

Step Attenuator

DATA REQUIREMENTS

MANUALS: A complete user and service manual and calibration procedure shall be provided with each unit in contractor format. Manuals shall be on CD/DVD‐ROM in Indexed Portable Document Format

(iPDF). The manuals shall comply with Data Item Description (DID) DI‐TMSS‐80527C and the Contract

Data Requirements List (DD Form 1423).