TECHNICAL NOTE. What is Wander MEASUREMENT SOLUTIONS ANRITSU CORPORATION

Transcription

1 TECHNICAL NOTE What is Wander MEASUREMENT SOLUTIONS ANRITSU CORPORATION

2 CONFIDENTIAL Copyright 2002 by ANRITSU CORPORATION The contents of this manual shall not be disclosed in any way or reproduced in any media without the express written permission of Anritsu Corporation.

3 Technical note What is Wander Digital Communications Marketing Dept. Measurement Solutions Anritsu Corporation What is Wander Wander is a phase variation at slow frequency of DC to 0Hz. It requires wider measurement range than Jitter. (The required range is at least x 0 9 ns according to ITU-T Rec. O.72.) The measurement unit of Wander is shown in ns (nanosecond), where Jitter is shown in UI (Unit Interval). Example: MHz : UI = about 0.4ns

4 Wander Measurement Items TIE (Time Interval Error) MTIE (Maximum Time Interval Error) TDEV (Time Deviation) Please see the operation manual that explains the MX50002A Wander Application etc., using figures. TIE: Time Interval error The TIE is defined as a phase difference between the measured signal and the reference signal. The unit is typically shown in ns. The phase difference of measurement time T is measured from the start time defined 0. So, TIE shows the phase change from the measurement start. MTIE: Maximum Time Interval Error The MTIE measures characteristics of a frequency offset and a phase transient Wander. It is evaluated by using parameter called Observation time τ. MTIE (τ) is defined as a maximum TIE peak to peak value in Observation time τ. The time range of τ (length) is shifted in all TIE data as it is holding the peak value, in order to calculate MTIE based on the measured TIE. These calculated MTIE (τ) are MTIE values at τ, and it continue to calculate at each τ. TDEV: Time Deviation The TDEV measures characteristics of spectrum quantity in Wander. It is also evaluated by using parameter called Observation time τ. In TIE value, TDEV(τ ) is defined as RMS with BPF(Band Pass Filter) whose center frequency is at 0.42/ τ. Total measurement time T should require at least 2 τ for high-accuracy TDEV(τ). 2

5 Noise Wander Measurement Output Wander Wander Generation Input Noise Wander Tolerance Noise Wander Transfer The Output wander evaluates Noise Wander which is generated from NE connected in a network. It is evaluated by measuring MTIE and TDEV, and it confirms that nothing exceeds the specified mask line. The Noise Wander Generation measures noise wander generated from the device under test by itself. It corresponds to Jitter generation for Jitter, and it shows the amount of wander emergence when inputting Wander free signal. It is evaluated by measuring MTIE and TDEV, and it confirms that nothing exceeds the specified mask line. The Input noise wander tolerance measures tolerance of the device under test against noise wander. When inputting the standard clock added noise wander to the device under test, it confirms the followings: Not causing any alarms Not causing the clock to switch reference Not causing the clock to go into holdover It confirms that the device under test has tolerance against noise wander in accordance with specified MTIE and TDEV mask line. (At present, only TDEV can be measured.) The Noise wander transfer evaluates the transfer characteristic of the device under test by inputting Noise wander modulated by TDEV Noise to the device under test, and by evaluating TDEV when outputting from the device under test. It confirms that nothing exceed the specified mask line. The Noise Transfer evaluates characteristics of LPF (Low Pass Filter) in the device under test. 3

6 Connection with MP580A and MP570A Optical input ➄ Electrical TX Electrical RX Optical output ➅ ➃ GPIB cable Wander Ref. Input RS232C interface for Wander data communication with external PC When measured wander, please connect between Wander Ref output and Wander Ref input or apply signal from external Reference generator Wander Ref. CLK output This sheet shows connection with MP580A and MP570A. Combined with MP570A, need to connect, and ➃ cable. Optical interface for DUT is➄ and ➅ points, and also when start wander measurement, need to connection or apply signal from external reference generator to Wander reference input. 4

7 MP580A Block Diagram External Modulation Input External Clock Input Transmitter side Sinusoidal Jitter Generator Jitter Modulator Clock Output Internal Ref Reference Output DCS External 5/0M Reference input Reference Loop Noise Wander Generator Wander Reference Output Receiver side Clock Input Reference Clock Input Jitter Demodulator Jitter Filters HP LP Demodulation Clock Output Peak RMS Detector Wander Reference Input Wander Demodulator 0Hz LP Filter TIE Detector RS-232C for PC 5

8 T T Noise Wander Generation measurement MX50002AWander Meas. Measuring and comparing Wander Generation mask NE Application software Timing signal ➃ ➄ STM-N output interface Observation interval t [s] Wander free Ref signal ex MHz Wander Ref output ➃ Wander Ref input ➄ DCS input This shows an example of Noise wander generation measurement. NE measures by translating Reference signal, for example 2.048MHz, into timing signal after Clock Recovery, based on input STM-N signal. At this point, Input Reference is shown by using Wander free signal. This figure shows that the signal is output from the Wander Reference Output of the MP580A, but the frequency reference can be branched. In addition, The frequency reference signal should be input to both DCS input and Wander Reference input of the MP580A in Wander measurement. 6

9 Noise Wander Tolerance measurement () Error & Alarm Monitoring NE ➃ Ref signal with TDEV Wander ex MHz Modulated by Wander Tolerance mask Noise STM-N output interface Wander Ref output T ➃ DCS input This shows an example of Noise wander tolerance (). It explains that NE measures by translating Reference signal, for example, 2.048MHz, into Timing signal after Clock Recovery based on input STM-N signal. Reference signal modulated by TDEV Noise in accordance with TDEV Noise Tolerance is input to Wander reference output of the MP580A. Monitoring error with the MP570A in this condition, it confirms error free. 7

10 Noise Wander Tolerance measurement (2) Error & Alarm Monitoring Modulated by Wander Tolerance mask Noise NE 7 0 STM-N output interface DCS input ➃ Wander Ref output ➄ DCS input ➄ ➃ T Ref signal with TDEV Wander This shows an example of Noise Wander Tolerance (2). It explains that NE measures by transmitting data as timing signal after Clock Recovery, based on STM-N input signal. Multi- STM-N signal is gained by inputting Wander reference output of the MP580A, modulated by TDEV Noise in accordance with TDEV Noise Tolerance mask, to DCS input of the MP570A. This signal is input to NE, and it confirms error free while monitoring with the MP570A in this condition. 8

11 T Noise Wander Tolerance measurement (3) MX50002A Wander Meas. Application software NE Error & Alarm Monitoring STM-N output interface ➃ ➄ Ref signal with TDEV Wander ex MHz Modulated by Wander Tolerance mask Noise Wander Ref output T ➃ Wander Ref input ➄ DCS input This shows an example of Noise wander tolerance measurement (3). It explains that NE measures by translating Reference signal, for example 2.048MHz, into Timing signal after Clock Recovery based on input STM-N signal. Reference signal modulated by TDEV Noise in accordance with TDEV Noise Tolerance mask is input to Wander reference output of the MP580A. Monitoring error with the MP570A in this condition, it confirms error free. This example measurement is almost the same as the example (), but it can monitor TDEV Noise generated from the MP580A by using Wander application. The frequency reference signal should be input to both DCS input and Wander Reference input of the MP580A in Wander measurement. 9

12 T T Noise Wander Tolerance measurement(4) MX50002A Wander Meas. Application software 000 Modulated by Wander Tolerance mask Noise NE Error & Alarm Monitoring STM-N output interface ➃ ➄ ➅ Ref signal with TDEV Wander DCS input ➃ Wander Ref output ➄ Wander Ref input, ➅ DCS input This shows an example of Noise Wander Tolerance measurement (4). It shows that NE measures by transmitting data as timing data after Clock Recovery, based on STM-N signal. Multi-STM-N signal is gained by inputting Wander reference output of the MP580A, modulated by TDEV Noise in accordance with TDEV Noise Tolerance mask, to DCS input of the MP570A. In this case, clock output of the MP580A, Clock Recovery, cannot be used. (Jitter modulation can not be done at the same time). This signal is input to NE, and it confirms error free while monitoring error with the MP570A in this condition. This example measurement is almost the same as the example (2), but it can monitor TDEV Noise generated from the MP580A by using Wander application. The frequency reference signal should be input to both DCS input and Wander Reference input of the MP580A in Wander measurement. 0

13 T Noise Wander Transfer measurement Cal. () MX50002A Wander Meas. Application software ➃ ➄ Loop back Ref signal with TDEV Wander Loop back Observation interval τ Modulated by Wander Tolerance mask Noise [s] T STM-N output interface Wander Ref input ➃ Wander Ref output ➄ DCS input First of all, Calibration is required in Wander Transfer measurement. The measurement cannot be selected when there is no calibration data. This example shows Calibration for Noise Wander Transfer measurement. Example () shows that NE measures by translating Reference signal, for example 2.048MHz, into Timing signal after Clock Recovery based on input STM-N signal. As this figure explains, Wander reference output modulated by TDEV Noise input to DCS of the MP570A, and DCS abstracts synchronous signals from data then loops back these abstracted signals to In/Out of STM-N signal. In this case, Clock (Clock output) of the MP580A, Clock Recovery, cannot be used. ( Jitter modulation cannot be done at the same time.) Calibration data is loaded on PC by performing Calibration with the MX50002A Wander application. In addition, when selecting Estimated Calibration, it is possible to measure without calibration by calculating possible Noise Wander and by loading possible data as Calibration data.

14 T Noise Wander Transfer measurement Meas. () MX50002A Wander Meas. Application software Measuring and comparing Wander Transfer mask 000 NE Timing signal ➄ ➃ STM-N output interface T Ref signal with TDEV Wander ex MHz Modulated by Wander Tolerance mask Noise Wander Ref output ➃ DCS input 7 T ➄ Wander Ref input This shows an example of Noise wander transfer measurement (2). It is possible to measure after calibration is performed. This is almost the same as Noise Wander Tolerance measurement (3). The MX50002A compares Calibration data and Measured result, and makes a graph (on the Application software), then compares these data and Mask. It can evaluates elimination of Noise Wander in LPF of NE. 2

15 T Noise Wander Transfer measurement Cal. (2) MX50002A Wander Meas. Application software STM-N output interface DCS input ➃ Wander Ref output ➄ Wander Ref input, ➅ DCS input ➃ ➄ ➅ Loop-back Ref signal with TDEV Wander Modulated by Wander Tolerance mask Noise T First of all, Calibration is required for Wander Transfer measurement. The measurement cannot be selected when there is no Calibration data. This example (2) shows that Calibration of Noise Wander Transfer measurement. It shows that NE measures by transmitting data as timing data after Clock Recovery, based on input STM-N signal. As this figure explains, Wander reference output modulated by TDEV Noise is input to DCS of the MP570A, and DCS abstracts synchronous signals from data then loops back these abstracted signals to In/Out of STM-N signal. In this case, Clock (Clock output) of the MP580A, Clock Recovery, cannot be used. (Jitter modulation cannot be done at the same time.) Calibration data is loaded on PC by performing Calibration with the MX50002A Wander application software. In addition, when selecting Estimated Calibration, it is possible to measure without calibration by calculating possible Noise Wander and by loading possible data as Calibration data. 3

16 [s] T Noise Wander Transfer Measurement Meas. (2) MX50002A Wander Meas. Application software Measuring and comparing Wander Transfer mask 000 NE Observation interval τ 0 T STM-N output interface ➃ ➄ ➅ Ref signal with TDEV Wander Modulated by Wander Tolerance mask Noise DCS input Observation interval τ T [s] ➃ Wander Ref output ➄ Wander Ref input, ➅ DCS input This shows an example of Noise Wander Transfer measurement (2). It is possible to measure after Calibration is performed. This is almost the same as Noise Wander Tolerance measurement (4). The MX50002A compares Calibration data and Measured result, and makes a graph (on the Application Software), then compares these data and Mask. It evaluates that NE doesn t amplify Noise Wander. 4

17 Confidential Wander TECHNICAL NOTE Specifications are subject to change without notice. ANRITSU CORPORATION MEASUREMENT SOLUTIONS , Minamiazabu, Minato-ku, Tokyo , Japan Phone: Telex: J34372 Fax: U.S.A. ANRITSU COMPANY North American Region Headquarters 55 East Collins Blvd., Richardson, Tx 7508, U.S.A. Toll Free: -800-ANRITSU ( ) Phone: Fax: Canada ANRITSU ELECTRONICS LTD. Unit 02, 25 Stafford Road West Nepean, Ontario K2H 9C, Canada Phone: Fax: Brasil ANRITSU ELETRÔNICA LTDA. Praia de Botafogo 440, Sala 240 CEP , Rio de Janeiro, RJ, Brasil Phone: Fax: U.K. ANRITSU LTD. 200 Capability Green, Luton, Bedfordshire LU 3LU, U.K. Phone: Fax: Germany ANRITSU GmbH Grafenberger Allee 54-56, Düsseldorf, Germany Phone: Fax: France ANRITSU S.A. 9, Avenue du Québec Z.A. de Courtabœuf 995 Les Ulis Cedex, France Phone: Fax: Italy ANRITSU S.p.A. Via Elio Vittorini, 29, 0044 Roma EUR, Italy Phone: Fax: Sweden ANRITSU AB Botvid Center, Fittja Backe Stockholm, Sweden Phone: Fax: Spain ANRITSU ELECTRÓNICA, S.A. Europa Empresarial Edificio Londres, Planta, Oficina 6 C/ Playa de Liencres, Las Rozas. Madrid, Spain Phone: Fax: Singapore ANRITSU PTE LTD. 0, Hoe Chiang Road #07-0/02, Keppel Towers, Singapore Phone: Fax: Hong Kong ANRITSU COMPANY LTD. Suite 79, 7/F., Chinachem Golden Plaza, 77 Mody Road, Tsimshatsui East, Kowloon, Hong Kong, China Phone: Fax: Korea ANRITSU CORPORATION 4F Hyun Juk Bldg , Yeoksam-dong, Kangnam-ku, Seoul, Korea Phone: Fax: Australia ANRITSU PTY LTD. Unit 3/70 Forster Road Mt. Waverley, Victoria, 349, Australia Phone: Fax: Taiwan ANRITSU COMPANY INC. 6F, 96, Sec. 3, Chien Kou North Rd. Taipei, Taiwan Phone: Fax: No. Wander-E-E--(.0) Printed in Japan AGKD