23-01621 Requirements Specifications attachment GKN.pdf

Requirements and Specifications attachment:

The National Institute of Standards and Technology (NIST) Radio Station WWVH requires a 10kW (40 kW PEP) AM solid state transmitter capable of operating at a frequency of 5 MHz.

Radio Station WWVH broadcasts continuous time and frequency signals on 2.5, 5, 10 and 15 MHz utilizing the conventional AM mode (A3E).

Information modulated on the standard carrier frequencies include a 1200Hz 0.8 second tone (tick) once per second, a 1500 Hz tone (tick) once per hour, a 45 second 440 Hz standard audio frequency once per hour, 500 and 600Hz standard audio frequencies alternating throughout the hour. WWVH also broadcasts a voice station identifier and time announcements as well as a binary encoded 100Hz time code signal. Detailed information about the broadcast can be found at https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvh.

Item 1: 10 kW (40kW peak to peak) solid state AM Transmitter System

Requirements:

1.1 Output Power: 10kW average power, 40kW peak envelope power

1.2 Output Power Stability: +/- 3 % at 0 to 100 % modulation

1.3 Modulation: A3E double side band with full carrier

1.4 Frequency: 5 MHz

1.5 Bandwidth: 9kHz

1.6 Harmonic Output Suppression: Greater than 60db below carrier at full rated power

1.7 Spurious Signals: At least 60 db below carrier at full rated power

1.8 Output Impedance: 50 ohms unbalanced

1.9 Output Connection: 1 5/8” EIA flange

1.10 External Frequency Standard: Must accept external frequency standard of 5 MHz @ 1 VRMS sinusoidal waveform and exhibit 50 ohms input impedance

1.11 External Frequency Connector: BNC

1.12 Provision for complete shutdown of RF output: (un-key the transmitter) if external frequency reference is absent. Transmitter cannot revert to free running internal oscillator upon loss of NIST reference frequency

1.13 Frequency Stability: Equal to the external frequency standard provided

1.14 Power Requirements: 208V 3 phase

1.15 Efficiency: Greater than 25%

https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvh https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvh

1.16 Audio input Frequency Range: 50Hz – 4.5 kHz

1.17 Audio Frequency Response: +/- 1 db across the audio input range

1.18 Audio Delay: No greater than 100nS from audio input connector to detected modulated output of the transmitter

1.19 Audio Input Impedance: 50 ohms unbalanced

1.20 Audio Input Connector: BNC

1.21 Audio Input Level: 1 dBm +/- 3

1.22 Modulation Level: adjustable to achieve 100% modulation of the carrier

1.23 Ambient Temperature: 10 t0 50 C.

1.24 Ambient Humidity: up to 90%

1.25 Chassis ground connection: Equipment will have a grounding connection for earth ground

1.26 Technology: Solid State, should not contain any vacuum tubes

1.27 Fault Protection: Inherent internal protection to protect transmitter in cases of potentially harmful faults including load changes such as transmission line shorts or opens

1.28 Metering: Output power and reflected power as well as critical parameters to evaluate transmitter performance and facilitate fault isolation

Item 2: Installation and Commissioning

2.1: Delivery and installation of required components to meet the requirements outlined in Item 1 and post installation test data documenting the requirement of item 1 are satisfied.

Item 3: Training

3.1: Provide Training to 3 station staff members. Training to include topics of operation, maintenance, and troubleshooting.

Item 4: Documentation

4.1 Technical manual(s). Provide Technical documentation of the transmitter, documents will include block diagrams, simplified and detailed schematics, functional description of the transmitter and subassemblies, alignment procedures, recommended troubleshooting procedures and component parts list.