Report. Bilateral Comparison on Time Differences Between Two Pulses Between TÜBİTAK UME and SASO NMCC GULFMET.TF-S1

Transcription

1 Report Bilateral Comparison on Time Differences Between Two Pulses Between TÜBİTAK UME and SASO NMCC GULFMET.TF-S1 (Rev. 1) April 21, 2017

2 Contents Contents Introduction Travelling Standard Participant Laboratories Time Schedule Measurement Technique Discussion of The Results... 6 References ANNEX A. Measurement Report of TÜBİTAK UME /28

3 1. Introduction It was planned to organize a bilateral comparison on Time Differences Between Two Pulses between SASO NMCC and TÜBİTAK UME, in the frame of the Project of Development and Realization Measurement and Calibration System for the National Measurement and Calibration Center (NMCC) at Saudi Standards, Metrology and Quality Organization (SASO). This comparison was also registered as GULFMET Supplementary comparison with KCDB identifier GULFMET.TF-S1. Time Interval measurements are very important for the traceability of measurements of time and frequency. This bilateral comparison was performed by measuring the time intervals generated by a Digital Delay Generator which is modified from DG645 model Digital Delay Generator of Stanford Research Systems (SRS). UME acted as the pilot institute. The travelling standard was provided by TÜBİTAK UME. TÜBİTAK UME was responsible to monitoring standard performance during the circulation and the evaluation and reporting of the comparison results. The bilateral comparison was carried out in accordance with the Technical Protocol of Bilateral Comparison on Time Interval Measurements between TÜBİTAK UME and SASO NMCC [1]. 2. Travelling Standard The travelling standard is derived from SRS DG645 Digital Delay/Pulse Generator of Stanford Research Systems. This system includes a single board computer (SBC) to send / receive command to the main system to configure output pulse of DG645 Digital Delay Generator, using TCPIP protocol. The device generates 12 pre-defined time interval at the range of 500 ps to 40 ms. At the rear panel of the unit there are 12 blue-led to display which time interval has been selected. Those time intervals can be selected by pressing the button which has been located at the rear panel. Each blue-led represents a time interval called Txx. The device requires 10 MHz external reference signal with the fractional frequency better than 1x In order to reduce trigger uncertainty on the output pulses for A and B channels, the Fast Time Rise Time module, model SRD1, used to reduce output pulse rise time to below 100 ps. The travelling standard (Figure 1), have identification as follows: SRS DG645 Digital Delay/Pulse Generator Single Board Computer (SBC) 2x Fast Time Rise Time module, model SRD1 Serial No: /28

4 a) b) Figure 1. Modified DG645 Delay Generator: a) front panel, b) rear panel of travelling standard. Travelling standard generates 12 pre defined time intervals with the following table of signal specifications. The specifications of output signals for AB and CD channels are closely the same. Table 1. Signal Specifications Measurement point Time Interval Signal Specification Frequency T ps 1 khz T02 2 ns 1 khz T03 10 ns 1 khz T04 50 ns 1 khz T ns 1.8 V p-p 1 khz T ns square wave 1 khz T07 6 μs DC offset: -0.9 V 1 khz T08 65 μs Pulse width: 200 ns 1 khz T μs 1 khz T μs 100 Hz T ms 100 Hz T12 40 ms 20 Hz Those time intervals are selected by pressing the switch on the rear panel and the corresponding led from led panel shows which time interval has been selected. 4/28

5 In this comparison the time intervals, T02, T04, T06, T08, T010 and T12 were selected in the measurement of both time interval counter and high speed oscilloscope. Due to specification of High Speed Oscilloscope of SASO, the measurement of T10 and T12 was not carried out in time interval measurement using high speed oscilloscope. The travelling standard was supplied by TÜBİTAK UME. 3. Participant Laboratories The pilot laboratory for this comparison was TÜBİTAK UME (Turkey). The contact details of the coordinator are given below: Pilot Institute: Coordinator : TÜBİTAK Ulusal Metroloji Enstitüsü (UME) Mesut YOĞUN Tel: Fax: mesut.yogun@tubitak.gov.tr The participating institutes and contact persons with their addresses are given in Table 2. Table 2. Participants Country Institute Acronym Shipping Address Contact Person Turkey TÜBİTAK Ulusal Metroloji Enstitüsü TÜBİTAK UME TÜBİTAK Ulusal Metroloji Enstitüsü (UME) TÜBİTAK Gebze Yerleşkesi Barış Mah. Dr. Zeki Acar Cad. No: Gebze-Kocaeli, TURKEY Mesut YOĞUN mesut.yogun@tubitak.gov.tr Tel: Saudi Arabia SASO The National Measurement and Calibration Center SASO NMCC Saudi Standards, Metrology and Quality Organization of The Kingdom of Saudi Arabia (SASO) Riyadh 11471, P.O. Box 3437 KINGDOM of SAUDI ARABIA Khalid S. AlDawood k.dawood@saso.gov.sa Tel: /28

6 4. Time Schedule The time schedule for the comparison is given in the Table 3. The circulation of travelling standard was organized so that to monitor the performance of the travelling standard. Each laboratory had 2 weeks to carry out the measurements and transportation. Table 3. Circulation Time Schedule Acronym of Institute Country Starting Date End Date TÜBİTAK UME Turkey SASO NMCC Saudi Arabia TÜBİTAK UME Turkey Measurement Technique The measurement techniques used by each participant is given in Annex A and Annex B. 6. Discussion of the Results The uncertainties of the measurements were calculated according to the JCGM 100 Guide to the Expression of Uncertainty in Measurement [2] for the coverage probability of approximately 95 %. All the contributions to the measurement uncertainty listed in the report were submitted by each participant. Each participant was also asked to provide the detailed uncertainty budget and the combined standard uncertainty for the aforementioned measurands. The uncertainty budgets provided by the participant and the full set of reported results can be found in Appendix A and Appendix B. The comparison reference value as a mean value and its uncertainty were calculated using Equations 1 and 2. (1) (2) 6/28

7 Where; is the result of first measurement performed by TÜBİTAK UME is the result of second measurement performed by TÜBİTAK UME is the expanded uncertainty of the first measurements performed by TÜBİTAK UME is the expanded uncertainty of the second measurements performed by TÜBİTAK UME The comparison reference values and its uncertainties for each time intervals are presented in Table 4 and Table 5 for the counter measurements and the high speed oscilloscope measurements respectively. Degrees of equivalence,, is calculated by subtracting the comparison reference value from the each measurements Equation 3 and its uncertainty,, is calculated according to the Equation 4. (3) (4) Where are the result of the measurement and its uncertainty performed by SASO. Degrees of equivalence values and their uncertainties can be found in Table 6 and Table 7 for the counter measurements and the high speed oscilloscope measurements respectively. The graphics of s are given in Figure 2-7 for the time interval counter measurements and in Figure 8 to 11 for the high speed oscilloscope measurements. 7/28

8 Table 4. Comparison reference values (CRV) and its uncertainties (k=2) using time interval counter for T02, T04, T06, T08, T10 and T12. Labs x i T02 T04 T06 T08 T010 T012 U x i U x i U x i U x i U x i U UME_ UME_ CRV x ref U ref x ref U ref x ref U ref x ref U ref x ref U ref x ref U ref Table 5. Comparison reference values and its uncertainties (k=2) using high speed oscilloscope for T02, T04, T06 and T08. Labs x i T02 T04 T06 T08 U x i U x i U x i U UME_ UME_ CRV x ref U ref x ref U ref x ref U ref x ref U ref /28

9 Table 6. Degrees of Equivalence and its uncertainty using time interval counter Time Interval x SASO U SASO x ref U ref DoE UDoE T T T T T T Table 7. Degrees of Equivalence and its uncertainty using high speed oscilloscope Time Interval x SASO U SASO x ref U ref DoE UDoE T T T T /28

10 DoE( T), ns DoE( T), ns Time interval, T02 SASO Figure 2. Measurement results for T02, using time interval counter Time interval, T04 SASO Figure 3. Measurement results for T04, using time interval counter. 10/28

11 DoE( T), ns DoE( T), ns Time interval, T SASO Figure 4. Measurement results for T06, using time interval counter Time interval, T08 SASO Figure 5. Measurement results for T08, using time interval counter. 11/28

12 DoE( T), ns DoE( T), ns Time interval, T10 SASO Figure 6. Measurement results for T10, using time interval counter Time interval, T SASO Figure 7. Measurement results for T12, using time interval counter. 12/28

13 DoE( T), ns DoE( T), ns Time interval, T02 SASO Figure 8. Measurement results for T02, using high speed oscilloscope Time interval, T04 SASO Figure 9. Measurement results for T04, using high speed oscilloscope. 13/28

14 DoE( T), ns DoE( T), ns Time interval, T06 SASO Figure 10. Measurement results for T06, using high speed oscilloscope Time interval, T08 SASO Figure 11. Measurement results for T08, using high speed oscilloscope. 14/28

15 References [1] Technical Protocol, Bilateral Comparison on Time Interval Measurements Between TÜBİTAK UME and SASO NMCC, UME-D4-TF01 (a), Rev.0, January 30, 2017 [2] Evaluation of measurement data - Guide to the Expression of Uncertainty in Measurement (GUM), JCGM 100, First edition, September 2008 (available on the BIPM website: 15/28

16 ANNEX A. Measurement Report of TÜBİTAK UME 1. PARTICIPANT INFORMATION Laboratory Name Contact Persons TÜBİTAK UME Mesut YOĞUN Telephone No Fax No Address TÜBİTAK UME Gebze Yerleşkesi Barış Mah.Dr. Zeki Acar Cad. No: 1 Gebze Kocaeli TURKEY 2. MEASUREMENT DATE (First measurements) (Last measurements) 3. ENVIRONMENTAL CONDITION Temperature Relative Humidity : ( 22 ± 2) C : (45 ± 10) %rh 4. REFERENCES USED IN MEASUREMENT Instrument Name Manufacturer Type / Model Time Interval Counter Agilent 53230A High Speed Oscilloscope LeCroy WAVEPRO 760Zi Digital Delay Generator SRS DG645 Primer Frequency Standard Agilent 5071A 16/28

17 5. MEASUREMENT METHOD Time Interval Measurements for bilateral comparison has been carried out by using both the time interval counter (TIC) and high speed digital oscilloscope. The time intervals between AB and CD channels outputs of DG645 Delay Generator were measured. The reference time intervals are defined between appearing rising slopes at the ends of the BNC connectors at the AB and CD outputs at the same trigger level. In order to reduce differential channel delays of the measurement devices and differential delays of the used connecting cables between Delay Generator and the measurement devices, each measurement performed at two stages as shown in Figure 1. Both the measurement and the delay generator devices are triggered externally from Cs frequency standard. a) b) START STOP START STOP AB CD ΔT 1 =TI+ x AB CD ΔT 2 =-TI+ x Figure 1. Measurement block diagram. Exemplary scheme of precise time interval measurements: a) normal configuration, b) configuration with replaced the cables between the START and STOP outputs of DG645. Then, the measured time interval will be approximately equal to: ΔTI = (ΔT 1 - ΔT 2 ) / 2 6. MEASUREMENT MODEL In the measurements carried out by using both counter and oscilloscope, same model function have been used: 17/28

18 : The time interval measurement between start and stop signal of DG645. : First time interval measurement between start and stop signal of DG645 for stage 1. : Second time interval measurement between start and stop signal of DG645 for stage 2. Δ : Time base correction factor. : Long term stability of DG645 Delay Generator. It estimated as about 60 ps with rectangular distribution. : Resolution effects of measurement devices. : Systematic uncertainty of measurement devices. 7. MEASUREMENT RESULTS The time interval delay measurement results are presented in Table 1 and Table 2 using Time Interval Counter and high speed oscilloscope respectively. Table 1a. Time Interval Counter Measurement results for first measurement Measurement Points Nominal Value Measured Time Interval Expanded Uncertainty T02 2 ns ns ns T04 50 ns ns ns T ns ns ns T08 65 μs ns ns T μs ns ns T12 40 ms ns ns 18/28

19 Table 1b. Time Interval Counter Measurement results for last (second) measurement Measurement Points Nominal Value Measured Time Interval Expanded Uncertainty T02 2 ns ns ns T04 50 ns ns ns T ns ns ns T08 65 μs ns ns T μs ns ns T12 40 ms ns ns Table 2a. High Speed Oscilloscope Measurement results for first measurement Measurement Points Nominal Value Measured Time Interval Expanded Uncertainty T02 2 ns ns ns T04 50 ns ns ns T ns ns ns T08 65 μs ns ns T μs ns 0.58 ns T12 40 ms ns 12 ns 19/28

20 Table 2b. High Speed Oscilloscope Measurement results for last (second) measurement Measurement Points Nominal Value Measured Time Interval Expanded Uncertainty T02 2 ns ns ns T04 50 ns ns ns T ns ns ns T08 65 μs ns ns T μs ns 0.58 ns T12 40 ms ns 12 ns 8. UNCERTAINTY BUDGETS The uncertainty budgets for first and last measurements are same and given in Table 3 and Table 4. Table 3. Uncertainty budget for time interval counter Contribution T02 T04 Standard Uncertainty T06 T08 T10 T12 Type A / B Distribution Time base A Normal Resolution A Normal Systematic B Rectangular Repeatability A Normal DG Stability B Rectangular Combined Unc Expanded Unc /28

21 Table 4. Uncertainty budget for high speed oscilloscope Standard Uncertainty Contribution T02 T04 T06 T08 T10 T12 Type A / B Distribution Time base A Normal Resolution A Normal DG Stability B Rectangular Repeatability A Normal Combined Unc Expanded Unc /28

22 ANNEX B. Measurement Report of SASO NMCC 1. PARTICIPANT INFORMATION Laboratory Name Prepared by SASO NMCC Waleed M. Al Harbi, Khalid S. AlDawood, Fahad A. AlMuhlaki Telephone No Measurement Carried out by Address Khalid S. AlDawood, Waleed M. Al Harbi, Fahad A. AlMuhlaki Saudi Standards, Metrology and Quality Organisation of The Kingdom of Saudi Arabia (SASO) Riyadh 11471, P.O. Box 3437 Kingdom of Saudi Arabia 2. MEASUREMENT DATE ENVIRONMENTAL CONDITION Temperature : (22 ± 2) C Relative Humidity : (45 ± 10) %rh 4. REFERENCES USED IN MEASUREMENT Instrument Name Manufacturer Type / Model Time Interval Counter Agilent 53230A Wide-Bandwidth Oscilloscope Agilent DCA-X86100D Digital Delay Generator SRS DG645 Primer Frequency Standard Agilent 5071A 22/28

23 5. MEASUREMENT METHOD Time Intervals between start and stop signals of Digital Delay Generator were measured using Universal Frequency Counter/Timer and High speed Oscilloscope 50 GHz. First, measured time difference between the start signal of Digital Delay Generator and the stop signal using Universal Frequency Counter/ Timer (Fig 1.). After that we change the cables (Fig 2.) to cancel delay of external cables. Second, measured time difference between the start signal of Digital Delay Generator and the stop signal using High speed Oscilloscope 50 GHz (Fig 3.). After that we change the cables (Fig 4.) to cancel delay of external cables. Because of the digital sampling oscilloscope has not external reference input, after and before starting each measurement, we calibrated internal oscillator of oscilloscope by using 10 MHz of Cs clock. 10 MHz Cs Digital Delay Generator TO AB CD CH1 CH2 Fig 1. Measuring difference between start signal of Digital Delay Generator and stop signal using Counter. Fig 2. Measuring difference between stop signal of Digital Delay Generator and start signal using Counter. 23/28

24 Fig 3. Measuring difference between start signal of Digital Delay Generator and stop signal using DS Oscilloscope. Fig 4. Measuring difference between start signal of Digital Delay Generator and stop signal using DS Oscilloscope. 6. MEASUREMENT MODEL 6.1 Measurement Model For Counter RES :The time difference between star signal of Digital Delay Generator and stop signal. : First time difference between stop signal of Digital Delay Generator and start signal. : Second time difference between stop signal of Digital Delay Generator and start signal. RES : Resolution for the Universal Frequency Counter. : Remaining systematic components for the Universal Frequency Counter. 24/28

25 6.2 Measurement Model For Digital Sampling Oscilloscope: RES :The time difference between star signal of Digital Delay Generator and stop signal. : First time difference between stop signal of Digital Delay Generator and start signal. : Second time difference between stop signal of Digital Delay Generator and start signal. RES : Resolution for the Digital Sampling Oscilloscope. 7. MEASUREMENT RESULTS Time Interval Counter Measurement Points Nominal Value First Measured Time Interval Second Measured Time Interval Measured Time Interval Uncertainty T02 2 ns T04 50 ns T ns T08 65 μs T μs T12 40 ms /28

26 High Speed Oscilloscope First Second Measured Measurement Nominal Measured Measured Uncertainty Time Interval Points Value Time Interval Time Interval T02 2 ns T04 50 ns T ns T08 65 μs Final Result : Digital Delay Generator Outputs Time Interval Counter Measured Time Intervals Uncertainty k=2 (95 %) T T T T T T /28

27 Digital Delay Generator Outputs High Speed Oscilloscope Measured Time Intervals Uncertainty k=2 (95 %) T T T T UNCERTAINTY BUDGETS Measuring Time Interval for the counter: Contribution T02 T04 Standard Uncertainty T06 T08 T10 T12 Type A / B Distrib ution Repeatability A Normal Systematic Uncertainty B Rect. Resolution A Normal Combined Unc. Expanded Unc /28

28 Measuring Time Interval for the high speed oscilloscope: Contribution T02 Standard Uncertainty T04 T06 T08 Repeatability Timebase Resolution Combined Unc. Expanded Unc Type A / B A A A Distribution Normal Normal Normal 28/28