Time & Frequency Metrology Division

Introduction

The responsibility to maintain the Pakistan standard time (PST) scientifically and to disseminate it to the users was assigned to the NPSL, Islamabad by decision of the Federal Cabinet in 1983. The responsibilities include the maintenance of time interval standard, establishment of the National Atomic Time Scale and realization and maintenance of the local Universal coordinated Time (UTC)
The National Atomic Time Scale has been established and maintained using three atomic frequency standards namely Cesium Beam Frequency Standard, Rubidium Frequency Standard and a GPS controlled frequency standard. The Master / Reference clock is driven by Rubidium frequency standard at present. The Pakistan Standard Time (PST) is transmitted at FM- Modulation (100±5% MHz), through Pakistan Broadcasting Corporation, Headquarters, Islamabad, for local users

Functions

The main functions of T&F Metrology Division are

• Realization of Primary Frequency Standards and maintenance of the National Standards related to Time &Frequency Metrology
• Generation, realization, maintenance and dissemination of Pakistan Standard Time (PST)
• Maintenance of traceability for time interval and frequency measurement through GPS controlled frequency standard
• Improvement of existing techniques test/ calibration as well as accuracy and precision of physical measurements through research to devise new techniques of measurement and calibration in the field of Time &Frequency
• To carry out test/calibration of precision measuring equipment and standards related with time, frequency and rpm to government/private sector and industries including defence organizations and other stakeholders
• To provide specialized training in “T&F-metrology and measurement uncertainty calculations” mainly to industry and organizations engaged in test and calibration activities
• To take part in inter-laboratory comparisons (ILC) at the national and international level to ensure credibility, traceability and validity of tests/measurement results produced during test/calibration
• To provide on-site test/calibration services to fulfill the demand of Customers according to provision in the QMS of NPSL

Location of Transmitter

(For Time Signals)
Place: NPSL, Islamabad
Latitude: 33º 40′ N
Longitude: 73º 2′ E

Calibration and Time Services

• Calibration of oscillators, temperature controlled quartz crystal oscillator and Rubidium Frequency Standards
• Calibration of frequency/time/revolution per minute related equipment such as Universal frequency counters/meters, Frequency/Signal Generators, Stopwatches(Mechanical/Digital), Tachometers (Contact/Non-contact type), Oscilloscopes, etc
• Time-of-day information provided through FM- transmission to Pakistan Broadcasting Corporation and local users

Available main equipment (supplied by Hewlett Packard/Tektronix/Fluke/ Marconi) used during calibration

• Cesium Beam Frequency Standard
• Rubidium Frequency Standard
• GPS Controlled Frequency Standard
• Microwave Frequency Counter
• Universal Time Interval Counter
• Phase Comparator
• Digital Phase meter
• Calibration Generator
• Time Mark Generator
• Leveled Sine wave Generator
• Distribution Amplifiers
• Phase Recorder
• Frequency/Time/Phase measurement system
• AM/FM Signal Generator
• RF-Power meter

PNAC Accredited Calibration Facilities

Measured Quantity Calibrating Range	Calibrating Range	Uncertainty (±)
Frequency (Hz)	1Hz-2.4GHz & 0.1 Hz-18 GHz.	4.1×10-10 MHz
Time (s)	1 s to 24 hrs.	6.0 × 10-3 s
RPM	For 60 rpm- 60,000 rpm & up to 15,000	6.0×10-3rpm 3.26×10-2 rpm

Contact Personnel

Head T&F Metrology Division
Phone: +92 51 9257462-7, Ext. 229
Fax: +92 519258162