Time and Frequency Standards Laboratory

Last updated

The Time and Frequency Standards Laboratory is a part of the National Physical Laboratory in New Delhi which maintains and calibrates the Indian Standard Time.


Features of the Time and Frequency Standards Lab include:

In the past, it once offered HF broadcast service operating at 10 MHz under call sign ATA to synchronise the user clock within a millisecond.

See also

Related Research Articles

International Atomic Time is a high-precision atomic coordinate time standard based on the notional passage of proper time on Earth's geoid. TAI is a weighted average of the time kept by over 450 atomic clocks in over 80 national laboratories worldwide. It is a continuous scale of time, without leap seconds, and it is the principal realisation of Terrestrial Time. It is the basis for Coordinated Universal Time (UTC), which is used for civil timekeeping all over the Earth's surface and which has leap seconds.

The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical science laboratory programs that include nanoscale science and technology, engineering, information technology, neutron research, material measurement, and physical measurement. From 1901 to 1988, the agency was named the National Bureau of Standards.

<span class="mw-page-title-main">Second</span> SI unit of time

The second is the unit of time in the International System of Units (SI), historically defined as 186400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each.

<span class="mw-page-title-main">Frequency standard</span> Stable oscillator used for frequency calibration or reference

A frequency standard is a stable oscillator used for frequency calibration or reference. A frequency standard generates a fundamental frequency with a high degree of accuracy and precision. Harmonics of this fundamental frequency are used to provide reference points.

In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Such a standard could be another measurement device of known accuracy, a device generating the quantity to be measured such as a voltage, a sound tone, or a physical artifact, such as a meter ruler.

<span class="mw-page-title-main">Metrology</span> Science of measurement and its application

Metrology is the scientific study of measurement. It establishes a common understanding of units, crucial in linking human activities. Modern metrology has its roots in the French Revolution's political motivation to standardise units in France when a length standard taken from a natural source was proposed. This led to the creation of the decimal-based metric system in 1795, establishing a set of standards for other types of measurements. Several other countries adopted the metric system between 1795 and 1875; to ensure conformity between the countries, the Bureau International des Poids et Mesures (BIPM) was established by the Metre Convention. This has evolved into the International System of Units (SI) as a result of a resolution at the 11th General Conference on Weights and Measures (CGPM) in 1960.

The Time from NPL is a radio signal broadcast from the Anthorn Radio Station near Anthorn, Cumbria, which serves as the United Kingdom's national time reference. The time signal is derived from three atomic clocks installed at the transmitter site, and is based on time standards maintained by the UK's National Physical Laboratory (NPL) in Teddington. The service is provided by Babcock International, under contract to the NPL. It was funded by the former Department for Business, Innovation and Skills; as of 2017 NPL Management Limited (NPLML) was owned by the Department for Business, Energy and Industrial Strategy (BEIS), and NPL operated as a public corporation.

<span class="mw-page-title-main">National Physical Laboratory (United Kingdom)</span> National Measurement Institution of the United Kingdom

The National Physical Laboratory (NPL) is the national measurement standards laboratory of the United Kingdom. It sets and maintains physical standards for British industry.

JJY is the call sign of a low frequency time signal radio station located in Japan.

Louis Essen FRS O.B.E. was an English physicist whose most notable achievements were in the precise measurement of time and the determination of the speed of light. He was a critic of Albert Einstein's theory of relativity, particularly as it related to time dilation.

<span class="mw-page-title-main">Indian Standard Time</span> Time zone, observed in India and Sri Lanka; UTC+05:30

Indian Standard Time (IST), sometimes also called India Standard Time, is the time zone observed throughout India, with a time offset of UTC+05:30. India does not observe daylight saving time or other seasonal adjustments. In military and aviation time, IST is designated E†. It is indicated as Asia/Kolkata in the IANA time zone database.

<span class="mw-page-title-main">Satellite navigation</span> Use of satellite signals for geo-spatial positioning

A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location to high precision using time signals transmitted along a line of sight by radio from satellites. The system can be used for providing position, navigation or for tracking the position of something fitted with a receiver. The signals also allow the electronic receiver to calculate the current local time to a high precision, which allows time synchronisation. These uses are collectively known as Positioning, Navigation and Timing (PNT). Satnav systems operate independently of any telephonic or internet reception, though these technologies can enhance the usefulness of the positioning information generated.

<span class="mw-page-title-main">National Physical Laboratory of India</span>

The CSIR- National Physical Laboratory of India, situated in New Delhi, is the measurement standards laboratory of India. It maintains standards of SI units in India and calibrates the national standards of weights and measures.

<span class="mw-page-title-main">Weather radio</span>

A weather radio is a specialized radio receiver that is designed to receive a public broadcast service, typically from government-owned radio stations, dedicated to broadcasting weather forecasts and reports on a continual basis, with the routine weather reports being interrupted by emergency weather reports whenever needed. Weather radios are typically equipped with a standby alerting function—if the radio is muted or tuned to another band and severe weather bulletin is transmitted, it can automatically sound an alarm and/or switch to a pre-tuned weather channel for emergency weather information. Weather radio services may also occasionally broadcast non-weather-related emergency information, such as in the event of a natural disaster, a child abduction alert, or a terrorist attack.

<span class="mw-page-title-main">NIST-F1</span> Atomic clock

NIST-F1 is a cesium fountain clock, a type of atomic clock, in the National Institute of Standards and Technology (NIST) in Boulder, Colorado, and serves as the United States' primary time and frequency standard. The clock took less than four years to test and build, and was developed by Steve Jefferts and Dawn Meekhof of the Time and Frequency Division of NIST's Physical Measurement Laboratory.

<span class="mw-page-title-main">Indian Regional Navigation Satellite System</span> Satellite navigation system

The Indian Regional Navigation Satellite System (IRNSS), with an operational name of NavIC, is an autonomous regional satellite navigation system that provides accurate real-time positioning and timing services. It covers India and a region extending 1,500 km (930 mi) around it, with plans for further extension. An extended service area lies between the primary service area and a rectangle area enclosed by the 30th parallel south to the 50th parallel north and the 30th meridian east to the 130th meridian east, 1,500–6,000 km (930–3,730 mi) beyond borders where some of the NavIC satellites are visible but the position is not always computable with assured accuracy. The system currently consists of a constellation of eight satellites, with two additional satellites on ground as stand-by.

<span class="mw-page-title-main">Quartz clock</span> Clock type

Quartz clocks and quartz watches are timepieces that use an electronic oscillator regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency, so that quartz clocks and watches are at least an order of magnitude more accurate than mechanical clocks. Generally, some form of digital logic counts the cycles of this signal and provides a numerical time display, usually in units of hours, minutes, and seconds.

<span class="mw-page-title-main">Coordinated Universal Time</span> Primary time standard

Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. It is within about one second of mean solar time at 0° longitude and is not adjusted for daylight saving time. It is effectively a successor to Greenwich Mean Time (GMT).

<span class="mw-page-title-main">Atomic clock</span> Extremely accurate clock

An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions between such states they interact with a very specific frequency of electromagnetic radiation. This phenomenon serves as the basis for the International System of Units' (SI) definition of a second:

The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency, , the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1.


  1. "Launching of Mobile Teleclock | National Physical Laboratory". Archived from the original on 8 January 2010.
  2. "Time and Frequency Standards | National Physical Laboratory". www.nplindia.org. Archived from the original on 31 December 2010.