Some standard content:
National Metrology Technical Specification of the People's Republic of China JJF1180-2007
Glossary and Definition of Time and Freguency MetrologyIssued on June 14, 2007
Implementation on September 14, 2007
Issued by the General Administration of Quality Supervision, Inspection and Quarantine JJF1180-2007
Glossary and Definition of Timeand Frequeney Metrology
JJF1180—2007
This specification was approved by the General Administration of Quality Supervision, Inspection and Quarantine on June 14, 2007 and came into effect on September 14, 2007.
Responsible unit: National Technical Committee on Time and Frequency Metrology Drafting unit: China National Institute of Metrology This specification shall be interpreted by the responsible unit
Main drafters of this specification:
JJF1180—2007
Jiazhishuxianliangshengshangxie
Ma Fengming (China National Institute of Metrology) Participating drafters:
Gao Xiaoxun (China National Institute of Metrology) Zhang Aimin (China National Institute of Metrology)sabspol
Ouoalb
Jiaguobiqichang#
Guoguoxing
1 Technical Foundation||t t||1.1 Time scale (time scale)
atomic second,
mean solar second
Universal time type (UT1)
International Atomic Time (TAI)
Coordinated Universal Time (UTC)
Beijing time
Julian day (JD)
Modified Julian day (MID)
Time and frequency standard
Brilliant atomic fountain time and frequency standard
Digital clock
Atomic clock
Quartz clock
White noise
Flicker noise
White phase noise
Flicker Phase noise
White frequency noise
Flash noise
Random walk frequency noise
Time interval
Time interval generator,
Time interval counter
Gate time
Mechanical stopwatch
Quartz electronic stopwatch
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Electric stopwatch
Millisecond meter
Time calibrator
Stopwatch calibrator
Electric stopwatch calibrator
Calibrator
2.18 clock speed
Time deviation||tt| |Time coding
Time comparison
Time synchronization
Synchronization uncertainty
Time transmission
Radio time station
TV time and frequency broadcasting
Network timing
Network time protocol
Telephone timing
Global Positioning System (GPS)
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Global Navigation Satellite System (GLONASS)
GPS common view method
Satellite two-way method
Carrier frequency phase measurement
Time standard deviation| |tt||Time standard
2.38 Maximum time interval error (MTIE) Time jitter
Time drift
3.1 Frequency
3.3 Phase
3.4 Phase difference
3.5 Phase shift
3.6 Frequency standard
3.7 Atomic frequency standard·
（5）
（6）
（7）
Yellow beam atomic frequency standard
Hydrogen atomic frequency standard·
Atomic frequency standard
Active atomic frequency standard
Passive atomic frequency standard||tt ||Quartz crystal frequency standard
Optical frequency standard
Quartz oscillator
Oven-controlled crystal oscillator
Temperature-compensated crystal oscillator
Nominal frequency value
Actual frequency value
Frequency deviation
Frequency difference
Frequency accuracy
Frequency stability
Long-term frequency stability
Short-term frequency stability
Allen standard deviation
Corrected Allen standard deviation
Sampling time
Number of samples
Measurement bandwidth
Phase noise
Daily aging Rate
Monthly drift rate
Power-on characteristics
Temperature characteristics
Load characteristics
Voltage characteristics
Frequency reproducibility
Frequency replication
Frequency synthesizer
Frequency counter
Universal counter
Frequency divider
Frequency multiplier
Mixer
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(10）
3.46 Phase-locked loop
Frequency difference multiplier
Frequency standard comparator
Dual mixing time difference method||tt ||Phase Comparator
Phase Comparison Dead Zone
Frequency Calibration
Input Sensitivity
Measurement Resolution
Comparison Uncertainty
Maximum Input Frequency Difference
GPS Controlled Frequency Standard
3.58·GPS Controlled Quartz Frequency Standard
JJF1180—2007
1 Technical Foundation
JJF1180-2007
Terms and Definitions of Time and Frequency Measurement
1.1 Time Scale (Time Scale) timescale The abbreviation of time coordinate, also called time scale. Select a basic unit of time (seconds) and accumulate from a specific starting point
. The points on the time scale represent moments: year 1.2 atomic second atomicse
口 hours, minutes, seconds. The difference between two points is the time interval. It is the basic unit of time in the current International System of Units and was adopted by the 11th International Conference on Weights and Measures in 1967. The first two hyperfine energy levels in the first spring have a transition of 9192631770 cycles. The meaning is: "A second is the duration of
."
1.3 mean solar seconds
Guryn solar seconds
The time derived from the
cycle of the earth
86400 minutes of the day
This unit was formally defined in 1820! The mean solar second is the mean solar day, which is simply understood as 1.4 of the average value of the true solar day in a year. Universal time (UT1) is a time accumulated in units of mean solar seconds. The moment when the mean sun passes below the meridian plane where the observer is located is called the observed time caused by the change of the sun's axis of rotation at the observer's location. The mean solar time of the prime meridian plane of the earth is called the world error (called polar shift), which is corrected and called UT1. It can accurately reflect the angular position of the earth in space. It is 3ms (k
1.5 international atomic seconds)
internat
in atomic seconds, starting from January 1, 1958
world time!
Using about 300 direct replicators of the definition of continuous seconds distributed around the world,
1.6 Coordinated Universal Time (UC
) is calibrated by atomic packages working on the time scale used by the world.
Universal Time, codenamed
, is the time scale from which the uncertainty of the length of the day begins to accumulate
. The free atomic time is calculated by the International Bureau of Weights and Measures, and then the highly stable and highly accurate International Atomic Time is found. coordinateduniversal time
The time scale generated by the coordination of International Atomic Time (TAI) and Universal Time (UT1). The time unit used is the same as TAI, which is the atomic second. The difference between UNV and OG is less than the integer second difference between OG and TAI. UTC is the internationally unified legal time. The time used by each country or region is a whole hour away from UTC. The Eastern Hemisphere is ahead and the Western Hemisphere is behind.
1.7 leap seconds
To keep the difference between UTC and UT1 less than 0.9s, the modified second introduced on UTC. The number of seconds in a minute changes to 61 (positive second) or 59 (negative second). The time for the correction of the second is notified to the timekeeping laboratories in various places by the International Bureau of Weights and Measures 10 weeks in advance. The preferred time for the correction of the second is the last minute of the end of June or the end of December. So far, it is positive second.
1.8Beijing timeBeijingtime
The standard time used uniformly throughout my country, ahead of UTC8h in time. 1.9Julian day (JD) julian day
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The number of days accumulated in decimal from noon on January 1, 4713 BC, universal time 1.10Modified Julian day (MJD) modifiedjulian day The number of days accumulated in decimal from midnight on November 17, 1858, universal time. For example, the modified Julian day corresponding to September 1, 2005 is MJD=53614d (plus 2400000.5 days is the omitted day). It is mainly used in astronomical timing and calculation of international atomic time as another mark of date. 1.11 epoch
The starting point of a century, or the starting moment of a timing system 1.12 Primary time frequency standard A device that directly reproduces the definition of the second (see atomic second). The actual reproduction value and its uncertainty are obtained through independent measurement and calculation. This uncertainty is called the accuracy of the standard and is expressed as a relative value. At present, only a few countries have developed time frequency standards with an accuracy of 10-15. 1.13 Cesium fountain primary standard A new type of time frequency standard device. Atoms are thrown vertically upward with a low initial velocity and then fall freely, similar to a fountain, hence the name. Six laser beams are used to lock the atom into an ultra-low temperature sticky ball, and then the atom is thrown up at an initial velocity of (3-4) m/s, and the rising height is nearly 1m. Compared with the traditional time-frequency standard, the transition curve width is greatly reduced, which can be less than 1Hz, which is convenient for accurate phase locking. Since the atomic movement speed is very low, the deviation introduced by some speed-related factors during reproduction is also greatly reduced, so a very high accuracy can be obtained. 1.14 Digital clock digitalclock
The specific display device of the time scale includes three main parts: the master oscillator, the counter and the display. It mainly displays the time of the day, instant, minute and second.
1.15 Atomic clock atomicclock
A digital clock with the atomic resonance frequency as the main oscillator frequency, in addition to displaying hours, minutes and seconds, also has second pulse output, external synchronization signal input and second pulse delay adjustment components. Currently, there are atomic clocks, hydrogen atomic clocks and atomic clocks as commodities.
1.16 Quartz clock quartzclock
A digital clock with a quartz crystal oscillator as the main oscillator. Mainly used to display hours, minutes and seconds. Devices with slightly higher accuracy have second pulse output and external synchronization functions. 1.17 Noise whitenoise
It has a continuous and uniform power spectrum density within a given frequency band, and is displayed as a nearly flat noise power curve on the spectrum analyzer.
1.18 Flicker noise flickernoise
A fast low-frequency noise. The power spectrum density is inversely proportional to the frequency, so it is also called 1 noise. 1.19 White phase noise whitephasenoise
Phase modulation of white noise on the frequency standard signal. It is manifested as frequency stability being inversely proportional to the sampling time. 1.20 Flicker phase noise flicker phase noise Phase modulation of flicker noise on the frequency standard signal. It is manifested as frequency stability being inversely proportional to the sampling time. 2
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1.21 White frequency noise whitefrequencynoise White noise modulates the frequency of the frequency standard signal. It is characterized by the frequency stability being inversely proportional to the square root of the sampling time. 1.22 Flicker frequency noise flickerfrequencynoise Flicker noise modulates the frequency of the frequency standard signal, and is characterized by the frequency stability being independent of the sampling time. The stability at this time is sometimes called the flicker flat zone.
1.23 Random walk frequency noise randomwalkfrequencynoise Noise that causes the frequency stability to be proportional to the sampling time. 2 Time
2.1 Instant/dateofday
A point on the time scale, or the reading of a specific clock. 2.2 Time interval timeinterval
The difference between two points on the time scale, or the time that elapses between two events. The time interval measured in time-frequency measurement is generally less than 1s. Such as milliseconds, microseconds, nanoseconds, picoseconds, etc. 2.3 Time delay
The transmission time of a time signal through a space, a cable or a part of a circuit, two electronic devices, etc. The difference between the arrival time and the occurrence time of the signal is called delay when measured in the time synchronization system, also known as time delay.
2.4 Time interval generator Time interval generator uses the cycle of the internal crystal oscillator as a reference to generate various time intervals through digital circuits and analog circuits (delay lines), with the minimum interval reaching 1ns. The interval value is given by the width of a single column pulse, the pulse period or the time difference of a double column pulse. 2.5 Time interval counter Time interval counter uses the counting method to measure the time interval between two electrical signals. The unit time selected for measurement is called the time base, which is generated by the crystal oscillator signal in the counter through frequency multiplication and division. Traditional time interval counters (TICs) only use the direct counting method, and the minimum interval (resolution) that can be measured is limited by the flip time of the trigger, generally 10ns. In modern times, some new types of TICs have emerged, which add extended technologies based on direct counting, such as interpolation, cursor method and A/D conversion method. The measurement resolution can reach tens or even several ps. 2.6 Timebase
The unit time used for time interval measurement, such as 1ns, 1js, 1ms. Select according to the minimum display value of the measuring instrument.
2.7 Gatetime
The time when the electronic gate is open when the counter measures. 2.8 Stopwatch
The simplest, low-precision time interval measuring instrument, generally started and stopped manually. 2.9 Mechanical stopwatch The entire structure is mechanical, with the period of the internal hairspring swing as a reference, and the measurement results are displayed with the scale value of the dial and the pointer stopping on the dial. The resolution is generally 0.1s. 3
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2.10 Quartz electronic stopwatch A simple electronic time interval counter, the time base used is generated by the internal crystal oscillator, and the measurement results are given with a digital display. The resolution is generally 0.01s.
2.11 Electric stopwatch uses 50Hz, 220V mains electricity as the power to start the motor and drive the pointer to rotate through the clutch. The position of the pointer on the dial determines the measured time interval. It is mainly used to measure the action time of mechanical relays. The measurement error is 50H frequency accuracy and the clutch delay
2.12 Millisecondmeter
A digital time interval measuring instrument with a time resolution of 0.1ms. It has more comprehensive functions and can measure the time interval of electrical signals as well as the time interval of mechanical contacts (such as the closing and opening of relays. 2.13 Time verification device
Interval verification device
A widely used medium-precision fashion measurement standard 2.14 Stopwatch verification device
Yatch verification device
Used to verify various electrical stopwatches, mechanical 2.15 Electric stopwatch verification
Alectronotive 2.16 Calibrator/calibrator is used to calibrate various stopwatches. It is used to calibrate milliseconds. It is a device that uses the crystal in the calibrator as a reference source to quickly determine the relative speed of a watch. The relative speed is measured in seconds, days or seconds.17 Clock difference clo
The reading of two clocks
Time difference
When the difference is less than 13,
Let the second pulse of clock A start the timer, and the second pulse of clock B stop the timer, and the measured value is △. Then the reading difference of the two clocks is AB=△T. If △T is positive, it means that the time displayed by clock A is ahead of clock B; if AT is negative, it lags behind. 2.18 Clock speed clock
The reading difference of two clocks is the conversion rate. Let the reading difference of clocks A and B at a certain time be and B=ATABI. After
, the average speed of clock A relative to clock B is. After a period of time, it becomes
If RAB is positive, it means that clock A is faster than clock B. If RAB is negative, then clock A RAB=(△TAB2-△TAB1)
is slower than clock B. The unit of R is usually ns/d, μus/d or ms/d. By eliminating the unit of the clock speed, the relative frequency deviation of the two clock master oscillators can be obtained from the relative speed of the two clocks. For example, if gC2us/d, then YNA METROLG
(c)-A-AA
2.19H difference dailyclocktimedifferencerate86400s
=2.32×10-11
The change in the reading difference of the two clocks after one day. If the reading difference of the two clocks A and B at a certain moment on the first day is △TAB1, and the reading difference at the same moment on the second day is △TAB2, then the daily difference is △TAB2-△TABEo daily difference is an important indicator of electronic stopwatches.
2.20 time deviation tirneoffset
The time difference between a time scale (or clock) and a reference time scale (or reference clock). The interval between the second pulses of the same mark in two time scales can be directly measured by a time interval counter, or it can be calculated indirectly, such as the deviation of the local coordinated universal time relative to the international unified coordinated universal time given in BIPM Time Bulletin 4
JJF1180-2007
, i.e., UTC(K)-UTC. 2.21 Time code timecode
Binary code of time signal, used for wireless or wired long-distance transmission of standard time. Generally contains year, month, day, hour, minute and second. ,
2.22 Time comparison timecomparison
The operation process of measuring and calculating the time deviation and the stability of the deviation of two time scales (clocks) using a comparison device. 2.23 Time synchronization timesynchronizationThe operation process of making two or more clocks have the same reading at a certain moment. 2.24 Synchronization uncertainty synchonSRn2NIS8The maximum range of the remaining time difference after clock synchronization depends on the synchronization method used. 2.25 Time transmission timecansfer
reference time in coded form or through
can also be directly decoded and used. Time is obtained.
2.26 Radio time receiving station
radiotime
or wirelessly transmits to a remote station for comparison and time synchronization with the company. The technical indicator is the transmission delay. By calculating or measuring important technical
radio stations used to send time information, the standard time is UTC. At the same time, the difference between UTC and UTI
can directly send local time. All information is sent in binary digital format over the frequency. 2.27 TV time frequency broadcast TVime
During the broadcast, the standard time is inserted in the TV
from a high frequency or from the clock in the Internet
.
TreguencyTransfer
is sent along with the TV signal. Standard time frequency ESnOH
is an accurate atomic clock, which is created by a special decoding receiver. The sub-clock and field and line scanning frequency standards in TV use the slave clock, so it can also be used as the Internet time servid
NITP) to send standard time information.
According to the Network Time Protocol (NTP), it is mainly used to calibrate user computers.
2.29 Network Time Protocol
networktin
protocol abbreviation
64-bit
set point number for sending time codes on the Internet. The first 32 bits are the total number of seconds from 00:01 on January 1, 1900 to the present UTC/2036. The last 32 bits represent the fractional part of the second, with a resolution of up to 200ps.
2.30 Telephone Time Service
precise time code information is sent through modems on the wired telephone network. It is mainly used to calibrate the clock in the user's computer. There are two receiving modes: unidirectional, without deducting the transmission delay; bidirectional, after deducting the transmission delay, the uncertainty can be better than 10ms.
2.31 Global Positioning System (GPS) globalpositioningsystem A high-precision global satellite radio navigation system established by the US Department of Defense. There are at least 24 satellites distributed on 6 fixed planes revolving around the earth. The satellite altitude is about 20,200km, and the rotation period is 11 hours and 58 minutes. Users on the earth can receive more than 4 satellites at the same time at any time to determine their own position. The satellite is equipped with a colored atomic clock and an atomic clock. The clock time is monitored by the ground every day, and the deviation relative to the standard time UTC (or GPS time) is given. The deviation value is kept less than 100ns, and the user can obtain the standard time information from the received navigation message to calibrate the local 526 Radio time station
radiotime
or wireless transmission to the remote for comparison and time synchronization with the company, the technical index is the transmission delay, by calculating or measuring the important technical
used to send the radio station time information, the standard time is UTC, while the difference between UTC and UTI
can directly send the local time. All information is sent in binary digital code. Time difference DUTI
2.27 TV time frequency transmission TVime
In the process of TVime
, it comes from a high frequency and also comes from
2.28 Network
In the clock of the Internet
.
TreguencyTransfer
is sent along with the full TV signal. Standard time frequency ESnOH is an accurate atomic clock, which is created by a special decoding receiver. The sub-clock and field and line scanning frequency standards in television use the slave clock, so it can also be used as the internet time service (NITP) to send standard time information.
According to the Network Time Protocol (NTP), it is mainly used to calibrate user computers.
2.29 Network Time Protocol
networktin
protocol abbreviation
64-bit
set point number for sending time codes on the Internet. The first 32 bits are the total number of seconds from 00:01 on January 1, 1900 to the present UTC/2036. The last 32 bits represent the fractional part of the second, with a resolution of up to 200ps.
2.30 Telephone Time Service
precise time code information is sent through modems on the wired telephone network. It is mainly used to calibrate the clock in the user's computer. There are two receiving modes: unidirectional, without deducting the transmission delay; bidirectional, after deducting the transmission delay, the uncertainty can be better than 10ms.
2.31 Global Positioning System (GPS) globalpositioningsystem A high-precision global satellite radio navigation system established by the US Department of Defense. There are at least 24 satellites distributed on 6 fixed planes revolving around the earth. The satellite altitude is about 20,200km, and the rotation period is 11 hours and 58 minutes. Users on the earth can receive more than 4 satellites at the same time at any time to determine their own position. The satellite is equipped with a colored atomic clock and an atomic clock. The clock time is monitored by the ground every day, and the deviation relative to the standard time UTC (or GPS time) is given. The deviation value is kept less than 100ns, and the user can obtain the standard time information from the received navigation message to calibrate the local 526 Radio time station
radiotime
or wireless transmission to the remote for comparison and time synchronization with the company, the technical index is the transmission delay, by calculating or measuring the important technical
used to send the radio station time information, the standard time is UTC, while the difference between UTC and UTI
can directly send the local time. All information is sent in binary digital code. Time difference DUTI
2.27 TV time frequency transmission TVime
In the process of TVime
, it comes from a high frequency and also comes from
2.28 Network
In the clock of the Internet
. Www.bzxZ.net
TreguencyTransfer
is sent along with the full TV signal. Standard time frequency ESnOH is an accurate atomic clock, which is created by a special decoding receiver. The sub-clock and field and line scanning frequency standards in television use the slave clock, so it can also be used as the internet time service (NITP) to send standard time information.
According to the Network Time Protocol (NTP), it is mainly used to calibrate user computers.
2.29 Network Time Protocol
networktin
protocol abbreviation
64-bit
set point number for sending time codes on the Internet. The first 32 bits are the total number of seconds from 00:01 on January 1, 1900 to the present UTC/2036. The last 32 bits represent the fractional part of the second, with a resolution of up to 200ps.
2.30 Telephone Time Service
precise time code information is sent through modems on the wired telephone network. It is mainly used to calibrate the clock in the user's computer. There are two receiving modes: unidirectional, without deducting the transmission delay; bidirectional, after deducting the transmission delay, the uncertainty can be better than 10ms.
2.31 Global Positioning System (GPS) globalpositioningsystem A high-precision global satellite radio navigation system established by the US Department of Defense. There are at least 24 satellites distributed on 6 fixed planes revolving around the earth. The satellite altitude is about 20,200km, and the rotation period is 11 hours and 58 minutes. Users on the earth can receive more than 4 satellites at the same time at any time to determine their own position. The satellite is equipped with a colored atomic clock and an atomic clock. The clock time is monitored by the ground every day, and the deviation relative to the standard time UTC (or GPS time) is given. The deviation value is kept less than 100ns, and the user can obtain the standard time information from the received navigation message to calibrate the local 5
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