Agilent Technologies E7401A manuale d’uso

Sign al Anal ysi s Meas ure ment Gu ide Agilen t T ech no logies EMC Se ries Analyzer s This gu ide documents firmware revision A.08.xx This m a nual pr ovides do c ume ntatio n for the fo llowing instru ments : E7401 A (9 kHz - 1.5 GHz) E7402 A (9 kHz - 3.0 GH z) E7403 A (9 kHz - 6.7 GH z) E7404A (9 kH z - 13.2 G Hz ) E7405A (9 kH z - 26.5 G Hz ) [...]

2 Noti ce The i nformation c ontained in this d ocument is s ubject to chang e witho ut notic e. Agilent T echnologies makes no warra nty of any kind with regard to this materi al, inc luding but not limi ted to , the im plied warrant ies of merchantabil ity and fit ness for a partic ular pu rpose. Agilent T echno l og ie s shall not be li ab le fo[...]

3 W ARNING This is a Safety Class 1 Product ( provided with a protective earth ground i ncorporated in the power cord). The mains plug shall be in serted only i n a socket out let provided wit h a protected eart h contact. Any interr uption of the protect ive conductor insi de or outside of the pr oduct is li kely to make t he produc t dangerous. I[...]

4 LIMIT A TION OF W ARRANTY The fo re g oin g war ra nty sh al l n o t appl y to de fe ct s re su l tin g fr om improper o r ina dequate maintenan ce by Buyer , Buyer -s upplied softwar e or inte rfa cing, una uthor ized modifi cati on or misuse, op er ation outsid e of the environmenta l sp ec ifi cations f or the p ro duct, or improp er site p re[...]

Co nt e nt s 5 1. Mak ing B asic Me asurem ent s Wh a t i s i n T his C hap ter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Te st E qui pm en t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [...]

6 Con tent s Tracki ng Generat or Unleveled Condi tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6 Me as uri ng De vi ce Ba nd wi dth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Me as uri ng Sto p Ba nd A tten ua ti on Us in g L og S wee[...]

7 1 Making Bas ic Measurements[...]

8 Ch a pt er 1 Making Basic M easurements What i s i n T his Chap ter What is in This Chapt er Thi s ch ap ter d e mo n st ra te s bas ic a n aly z e r m easu re m e n t s wi th examples of typ ical measur ements; each m easurement f ocuses o n differ ent func tions. T he measur ement procedures c overe d in this cha p t e r are li ste d be lo w . [...]

Chapter 1 9 Making B asic Measurements What is in This Chapter Te s t E q u i p m e n t T e s t E q ui pm en t S pec if i cat io ns Re co m m end e d Mo de l Signal Sour ces S i g n a l G e n e r a t o r ( 2 ) 0 . 2 5M H z t o 4 . 0G H z Ext Ref Input E4433B or E443XB ser ies Adapters T ype-N (m) to BN C (f) (3) 1250-0780 T er m inati on , 50 Ω T[...]

10 Ch a pt er 1 Making Basic M easurements Compari ng Signal s C omp ari n g S ign als Using the analyzer , you c an easily compare frequency a nd amplitude differ ences bet ween signal s, s uch as ra dio or te levisi on signal s pectr a. The anal yzer del ta marker f uncti on lets y ou compare two signa ls when both ap pear on t he screen at one t[...]

Chapter 1 11 Making B asic Measurements Comp ari ng Sign als Figure 1- 1 Placing a Marker on the 10 MH z Signal 9. Pre ss Marker , Delta , to a c tivate a s ec ond marker at the p os i tio n of t he fir st ma rke r . 10. Move the second marker to another s ignal pea k using the front- panel knob , or by pr essing Peak Search and then eit her Next P[...]

12 Ch a pt er 1 Making Basic M easurements Compari ng Signal s Figure 1 -2 Using the Marker Del ta Function Signal Comparison Example 2: Measure the fr equency and ampl itude di fference b etween tw o signals that do not a ppear on the screen a t one ti me. (Thi s techniq ue is us eful for harmoni c distor ti on tests when narro w span a nd narrow [...]

Chapter 1 13 Making B asic Measurements Comp ari ng Sign als 10. Pr ess Mar ker , Delta to anchor the posi tion of the fi rst marker a nd ac tivat e a s econ d mark er . 11 . Pr ess FREQUENCY , Ce nter Fr eq , a nd the ( ↑ ) key to in crea se the ce nt er frequency by 1 0 MHz. The first marker m oves to the lef t edge of the scree n, at the ampli[...]

14 Ch a pt er 1 Making Basic M easurements Resolvi ng Sign als of Equal Amplitude Resolving Sign als of E qual Amplitude T w o equal -amplitude i nput si gnals that a re close in fr equency c an ap pear as a sin gle si g nal tr ace on the ana lyzer di spl ay . R espo nding to a singl e-freq uency signa l, a swept-tuned a nalyz er traces out the sha[...]

Chapter 1 15 Making B asic Measurements Resolvi ng S ignals of Equal Ampl itude Resolving Signals Exam ple: Resolve tw o signals of equal amplitude w ith a frequenc y separatio n of 100 kHz. 1. Connect two sourc es to the analyzer i nput a s shown in Figure 1 -4 . Figure 1-4 Setup for O btainin g T wo Signals 2. Set one s ourc e to 300 MHz. Set the[...]

16 Ch a pt er 1 Making Basic M easurements Resolvi ng Sign als of Equal Amplitude Figure 1-5 Unresolved S ignals of Equal Amplitude 4. Since the resolut ion bandwidth must be l ess than or eq ual to the frequency sep arati on of the two signal s, a resoluti on bandwidth of 100 kHz m us t be used. Chang e t h e r es o l ut io n ban d wid t h to 10 0[...]

Chapter 1 17 Making B asic Measurements Resolvi ng S ignals of Equal Ampl itude 5. Decreas e the vi deo bandwidth to 1 0 kH z, b y pressing Vide o B W , 10, kHz . T wo sig nal s ar e now vis ibl e as sh o w n in Figur e 1 -7 . Use the front- panel knob or step keys t o f urther re duce the r esolution bandwidth a nd better res olve the signals. Fig[...]

18 Ch a pt er 1 Making Basic M easurements Resolvi ng Small Si gnals Hi dden b y Lar ge Signals Resolvin g Sm all Signals Hidde n by Large Signals When deal ing with the resol utio n of si gnals that are c lose tog ether a nd not equ al in amplitude, y ou must consider the shape of the I F filt er of the a n alyz e r , as we l l as i ts 3 dB ban d [...]

Chapter 1 19 Making B asic Measurements Resolvin g Small Sign als Hidden by Lar ge Sign als Resolving Signals Exam ple: Reso l ve two inp ut si gna ls with a fre q ue ncy se p arat ion of 155 kHz and an am plitu de separation of 60 dB. 1. Connect two sourc es to the analyzer i nput a s shown in Figure 1 -9 . Figure 1-9 Setup for O btainin g T wo Si[...]

20 Ch a pt er 1 Making Basic M easurements Resolvi ng Small Si gnals Hi dden b y Lar ge Signals 5. Set the 3 00 MHz signal to the re ference leve l by pressi ng Mk r → and then Mkr → Ref Lvl . If a 10 kHz filter w ith a typic a l sha pe f actor of 1 5:1 i s us ed, the filt er wil l hav e a ba ndwi dth o f 150 kHz at the 60 dB poin t . Th e half[...]

Chapter 1 21 Making B asic Measurements Resolvin g Small Sign als Hidden by Lar ge Sign als 7. Set the resol ution bandwidth to 30 kH z by pressi ng BW/A vg , Res BW , 30, kHz . When a 30 kHz filter is used, the 60 dB band width could b e as wid e as 450 kHz. Since the hal f-bandwidth ( 225 kHz) is wider than the freq u e n cy sep ara tio n , the s[...]

22 Ch a pt er 1 Making Basic M easurements Making Bet ter Frequenc y Measurements Maki ng Bett er Fr equen cy Meas ure ments A buil t-in fr equ e n cy cou n ter incre a ses the re so l u t io n an d ac cura cy of the f requency rea dout. Wh en using thi s funct ion, if t he r atio of the resolu t i on ban dw id t h to the sp an is t o o sma ll (le [...]

Chapter 1 23 Making B asic Measurements Maki ng Better Frequenc y Measur ements NOTE Ma rker count pr operly functi ons onl y on CW s ignals or discrete s pectral component s. The marker must be > 26 dB abov e the noi se. 9. Increa se the counte r resolution b y pres sing Re solu tion an d t h e n enteri ng the des ired res olution using the s t[...]

24 Ch a pt er 1 Making Basic M easurements Decreasing the Frequency Span Ar ound t he Signal Decreas i ng the Freq uency Spa n Around the Signal Us ing th e ana ly ze r s ig nal trac k f un ct io n, y ou c an qui ckly d ec r eas e th e span while keeping the si gnal at center frequenc y . This is a fast way to take a c loser l ook at the area aroun[...]

Chapter 1 25 Making B asic Measurements Decreasing the Frequency Span Around the Signal Figure 1- 14 Detected Signal 8. T urn on the f requency tracking f unction by press FREQUENCY an d Signal T rack and the si gnal will move to the center o f the sc reen, i f it is not a lrea dy posi tioned ther e. Se e figure Fig ure 1- 15 . (N ot e that the mar[...]

26 Ch a pt er 1 Making Basic M easurements Decreasing the Frequency Span Ar ound t he Signal 9. Reduce span a nd resoluti on bandwid th to zoom i n on the m arked si g nal by p re s si ng SP AN , Spa n , 20 0, kHz . If the span chang e is la rge e nough, span wi ll decr ease in steps a s automatic zoom is completed . See Fig ure 1- 16 . Y ou can a [...]

Chapter 1 27 Making B asic Measurements T racki ng Drif ti ng Sign als T rackin g Driftin g Signals The signal track func tion is usef ul f or tracking drifti ng signals th at drift r elativel y slowly . T o place a marker on the si gnal you w ish to track, use P eak S earch . Pressing FREQUENCY , Sig nal T rack (On) wil l bring that signa l to the[...]

28 Ch a pt er 1 Making Basic M easurements T racki ng Drif t ing Signals Figure 1 - 1 7 Signal Wit h Default Span 4. Press Peak Search . 5. Set the spa n to 10 M H z by pre ssi n g SP AN , Span , 10, MH z . See Fi g ur e 1- 18 . Figure 1 - 1 8 Signal Wi th 10 MHz S pan 6. Press SP AN , Spa n Zo om , 500, kHz . Notice t hat the si gnal has been held[...]

Chapter 1 29 Making B asic Measurements T racki ng Drif ti ng Sign als Figure 1- 19 Signal W ith 50 0 k Hz Span 7. T une the frequency of the si gnal generator in 10 kHz increments. Notice that the center frequency of the a nalyzer also changes i n 10 k Hz increments, cent ering the signal with each i ncr ement. See Figu r e 1- 20 . Note that the c[...]

30 Ch a pt er 1 Making Basic M easurements T racki ng Drif t ing Signals 8. The signal frequenc y drift can be r ead from the scree n if both the sig nal t rac k a nd mark er d el t a fu nc ti o ns are act i ve. Se t t he a nal yze r and si gna l gen e r at o r as fo l lo w s : a. Pre ss Marker , Delta . b. T une the fre quency of the signa l gener[...]

Chapter 1 31 Making B asic Measurements T racki ng Drif ti ng Sign als d. Set the c enter f requency to 300 MHz by pressing FREQUENCY , Ce nter Fre q , 300, MH z . See Fi gure 1 -22 . Figure 1-22 Signal W it h Default Span 4. Pre ss Peak S earch . 5. Set the s pan to 10 MHz b y pressing SP A N , Sp a n , 10, MH z . See Figu r e 1- 23 . Figure 1-23 [...]

32 Ch a pt er 1 Making Basic M easurements T racki ng Drif t ing Signals 6. Press SP AN , Spa n Zo om , 500, kHz . Notice t hat the si gnal has been held in the c enter o f the d isplay . See Figu re 1- 24 . Figure 1 -24 Signal Wit h 5 00 KHz Span 7. T urn off t he sig nal track func tion b y pressing FREQUENCY , Sign al T rac k (Off ). 8. T o meas[...]

Chapter 1 33 Making B asic Measurements T racki ng Drif ti ng Sign als Figure 1-25 V iewing a Dri fting S ignal W it h Max Hold and Clear W rite[...]

34 Ch a pt er 1 Making Basic M easurements Measuring Lo w Level Signals Measur ing Low L evel S ignals The abili ty of the analyzer to measure low level s ignals is limited by t he noise g enerated i nside t he analyzer . A signal m ay be masked b y the no ise flo or so th at it is n ot vis ibl e. Thi s s ens itiv ity to low le vel sign als is affe[...]

Chapter 1 35 Making B asic Measurements Measuring Lo w Le vel Signals 10. Reduce the s pan to 1 MHz. Press SP AN , Sp an , and then use the step- down key ( ↓ ) until the spa n is set to 1 MHz. See Figu re 1 -26 . Figure 1-26 Low-Level Sign al 11 . Pr ess AMPL I TUDE , Attenuation . Pr e ss the st e p-u p key ( ↑ ) to select 20 dB a tte nuation[...]

36 Ch a pt er 1 Making Basic M easurements Measuring Lo w Level Signals 12. T o see t h e s ig na l m ore cle a rly , ent e r 0 dB . Ze ro de ci bels of attenuat ion makes the s ignal more visib le. See Fig ure 1- 28 . Figure 1 -28 Using 0 dB Attenuation CAUTIO N Before connec ting ot her sig nals to t he anal yzer input , increa se the RF attenuat[...]

Chapter 1 37 Making B asic Measurements Measuring Lo w Le vel Signals 9. Place the signa l at center f requency by pressing Peak Search , Marker → , Mk r → CF . 10. Pr ess BW/Avg , Res BW , a n d th e n ↓ . Th e low leve l sig nal app e a rs more cl early because the noi se l evel is reduced. As shown i n Figu r e 1-29 . A # m ark appears nex[...]

38 Ch a pt er 1 Making Basic M easurements Measuring Lo w Level Signals 3. On the anal yzer , perform a f acto ry preset by pressi ng Preset , Factor y Pres et ( if p r es e nt) . 4. Set the c enter f requency of the ana lyzer to 300 MHz by pressing FREQUENCY , Cen ter Freq , 300, MHz . 5. Set the spa n to 5 MH z by pre ssing SP AN , Sp an , 5, MHz[...]

Chapter 1 39 Making B asic Measurements Measuring Lo w Le vel Signals NO TE The video band width must be s et wi der than the resolut ion band width w hen m eas ur ing im pu ls e n oi se l e vel s. Figu r e 1-31 D ecr easing V ide o Band width Measuring Low Level S ignals Example 4: If a s ignal l evel i s very close t o the noise fl oor , video av[...]

40 Ch a pt er 1 Making Basic M easurements Measuring Lo w Level Signals 1. Connect a s ignal g enerator to the ana lyzer input. 2. Set the signal gene rator freq uency to 300 M Hz with an amplitude of − 80 dBm. 3. On the anal yzer , perform a f acto ry preset by pressi ng Preset , Factor y Pres et ( if p r es e nt) . 4. Set the c enter f requency[...]

Chapter 1 41 Making B asic Measurements Measuring Lo w Le vel Signals 11 . T o set the num ber of samples , use the numeric keypad. For example, press Average (On) , 25, Ent er . As sh o w n in Fig ure 1- 33 . Du ri ng av era gi n g, th e cur r ent sa mple numbe r ap pe ar s at the l e ft side of the g ratic ule. The number of s am ples eq uals the[...]

42 Ch a pt er 1 Making Basic M easurements Ident ifying Dist ortion Produ cts Identifyin g Dist ortion Pro ducts Distortion from the Analyzer Hi gh l eve l inp ut s ign al s m ay c aus e a nal yze r dis tor tio n pro duc ts th at coul d mask the r eal disto rtion measured on the i nput sig nal. Using trace 2 and t he RF attenuator , you c an dete r[...]

Chapter 1 43 Making B asic Measurements Ident ifying Di sto rtion Produ cts Figure 1-34 Harmonic Distortion 8. Change the center f requen cy to the va lue of one of the o bserved har mon i cs by pre ssi n g Peak Search , Next P eak , Mark er → , Mkr → CF . 9. Chan ge t he span to 50 MH z: p ress SP AN , Spa n , 50, MHz . 10. E nsu re t h at the[...]

44 Ch a pt er 1 Making Basic M easurements Ident ifying Dist ortion Produ cts 12. T o deter mine whether the har monic distor tion p roducts are generated by the analy zer , fir st save the screen d ata in t race 2 as fo ll ows : a. Pre ss T race/View , T race (2) , then Clear W rite . b. Allow the tr ace to update (t wo sweeps) and press T race/Vi[...]

Chapter 1 45 Making B asic Measurements Ident ifying Di sto rtion Produ cts Figure 1-37 No Harmonic Distortion Third-Order Inter mod ulation Distortion T wo-tone, third- order inter modulation d istort ion is a common test i n communication s ystems. When two signal s are pr esent i n a non-li near syst e m , the y ca n in t e rac t an d cre a te t[...]

46 Ch a pt er 1 Making Basic M easurements Ident ifying Dist ortion Produ cts Figure 1 -38 Third -Order Int ermodulation E quipment Setup NOTE The combiner shoul d ha ve a high deg ree of isolatio n between the two input po rt s so th e sour ce s do n o t in ter mod ul ate. 2. Set one source (signal genera tor) to 300 MHz and the other sour ce to 3[...]

Chapter 1 47 Making B asic Measurements Ident ifying Di sto rtion Produ cts The anal yzer automati cally sets the attenuati on so that a s ignal at th e r ef ere n c e le v el wi ll b e a ma xi mu m o f − 30 d B m at t h e in pu t mixe r . 10. Pr ess BW/Avg , Res BW , and then use the step-d own key ( ↓ ) to redu ce the re solution b andwidth u[...]

48 Ch a pt er 1 Making Basic M easurements Ident ifying Dist ortion Produ cts Figure 1 -40 Measuring t he Distortion Product[...]

Chapter 1 49 Making B asic Measurements Measuring Signal- to -No ise Me as ur ing Si gn al - to- N oi se The signal -to-no ise measurement procedure below may be a dapted to mea su re an y sig nal i n a s y st em if th e s ig nal (car rier ) i s a d is c ret e ton e. If th e sig nal in yo ur syst em is mod ulate d, it will be nec essar y to m odi f[...]

50 Ch a pt er 1 Making Basic M easurements Measuring Si gnal- t o-Noise 11 . P ress More , Funct ion , Ma r k er N o is e to v iew the r es ults of the s i gna l t o noise measurement. See Fig ure 1- 41 . Figure 1 -41 Measuring t he Signal-to-Noise Read the s ignal-to- nois e in dB/Hz, t hat is with the noise v alue determined for a 1 Hz noise band[...]

Chapter 1 51 Making B asic Measurements Making Noise Measurements Making Noise Measurements There are a variety of way s to measur e noise p ower . The firs t decisi on you must make i s whether you want to measure no ise power at a specific frequenc y or the total p ower over a speci fied f requency range , for exa mple over a channel bandw idth. [...]

52 Ch a pt er 1 Making Basic M easurements Making No ise Measurements Fi gu re 1 -42 Sett in g the At ten ua t ion 8. Activate the nois e marker by pressi ng Ma rker , More , Fu nct ion , Mar ker Noi se . Note that t he disp lay det ection automat ically c hanged to “ Av g ” which can b e manually set by p ressing Det/D emod, Average (V ideo/RM[...]

Chapter 1 53 Making B asic Measurements Making Noise Measurements Figure 1-43 Activating the Noise Marker 9. The noi se marker v alue is based on t he mean of 5 % of t he total number of sweep poi nts centered at the marker . The points aver aged span one-half of a d ivision. T o see the effect , move the marker to the 50 MH z sig n al by pr e ssin[...]

54 Ch a pt er 1 Making Basic M easurements Making No ise Measurements NOTE Notice the video b andwidth cha nged to 1 00 kHz. The r atio between the video b andwidth (VBW) and the resolu tion bandwidth (RBW) must be ≥ 10/ 1 to maintai n the acc uracy of t he measure ment. Figu re 1-45 Increa sed R es oluti on Ban dwidt h 11 . Return the r esolutio[...]

Chapter 1 55 Making B asic Measurements Making Noise Measurements Figure 1-46 Noise Marker in Signal Skirt 13. Set the analyzer to zero span at the marker fr equency by p ressing Mk r → , Mkr → CF , SP AN , Zer o Sp a n , Ma rke r . Note that the m arker amplitude v alue i s now corr ect sinc e all points a veraged a re at the same fr equency a[...]

56 Ch a pt er 1 Making Basic M easurements Making No ise Measurements Noise Measurement Example 2: The Normal m arker can also be u sed to make a s ingle freq uency measurement as desc ribed in t he pre vious example , again using vi deo filt e r in g or av er ag ing to obt a in a re a so n abl y sta bl e m easu r eme n t. Wh ile v ideo av e ra gi [...]

Chapter 1 57 Making B asic Measurements Making Noise Measurements 10. Measure the power b etween m arkers by pressing Marker , Mo re , Func tion , Band Powe r . The analy zer displays t he total power between the ma rkers. Se e Fi gur e 1- 48 . 11 . Add a discrete tone to see t he eff ects of the rea ding. T urn on the inter nal 50 M Hz amplitude r[...]

58 Ch a pt er 1 Making Basic M easurements Making No ise Measurements Figure 1 -49 Measuring t he Power in the Span[...]

Chapter 1 59 Making B asic Measurements Demodulating AM Signal s (Using the Analyzer As a Fixed T uned R eceiver ) Demodulat ing AM Sign als (Using the Ana lyzer As a Fixed T uned Recei ver) The zero sp an mode c an be used to r ecover amplit ude modulation on a carr ie r si gn a l. Th e an a lyz er op erat e s as a fix e d-t u n e d re ce i ver i [...]

60 Ch a pt er 1 Making Basic M easurements Demodulat ing AM S ignals ( Using the An alyzer As a Fix ed T uned Receiver) b. RF Output Power – 10 dB m c. AM On d. AM Rate 1 kHz e. AM Depth 80% 2. Set the a nalyzer a s foll ows: a. Pre ss Preset , F actory Pre set (if present). b. Set the c enter frequenc y to 300 MHz by pressi ng FREQUENCY , Center[...]

Chapter 1 61 Making B asic Measurements Demodulating AM Signal s (Using the Analyzer As a Fixed T uned R eceiver ) 6. Selec t zero sp an by ei ther pre ssing SP A N , 0, Hz ; or pressing SP AN , Zer o Span . See Fi gur e 1 -51 . 7. Change the sweep time to 5 m s by pre ssing Sweep , Sweep Time (M an ), 5, ms . 8. Sinc e the modulati on i s a st ead[...]

62 Ch a pt er 1 Making Basic M easurements Demodulat ing AM S ignals ( Using the An alyzer As a Fix ed T uned Receiver) Figure 1 -52 Measuring Modulation In Zero Span Figure 1 -53 Measuring Modulation In Zero Span 9. Use markers and d elta markers to measure the ti me par ameters of the wavef orm. a. Pre ss Marker and center the marker on a peak u [...]

Chapter 1 63 Making B asic Measurements Demodulating AM Signal s (Using the Analyzer As a Fixed T uned R eceiver ) Figure 1-54 Measuring Ti me Parameters 10. Y ou can t u rn yo u r an al yze r i nto a % A M in d ica t o r as fo l lows : a. Set tri gger to f ree run b y pres sing Tr i g , Free Run . b. Set the sweep t ime to 5 seconds by pres sing S[...]

64 Ch a pt er 1 Making Basic M easurements Demodulat ing AM S ignals ( Using the An alyzer As a Fix ed T uned Receiver) Figure 1 -55 Continuous Demodul ation of an AM Signal[...]

Chapter 1 65 Making B asic Measurements Demodul ating F M Sign als Demodulat ing FM S ignals As with amplit ude mod u lation (see page 59 ) y ou can utilize zer o span to demodulate an F M signal. How ever , unlike t he AM case, you cannot simply t une to the c arrier f req uency and widen the resol ution bandwidth. Th e reason i s that t he env el[...]

66 Ch a pt er 1 Making Basic M easurements Demodu lating FM Si gnal s 4. Set the spa n to 1 MH z by pre ssing SP AN , Sp an , 1, MHz . 5. Se t th e Y -A x is Un it s t o dB m by p re s s in g AMPLIT UDE , Mo re, Y -Axi s Units, dBm . 6. Set the reference leve l to – 20 dB m b y pre ssing AMPLITUDE , Ref Leve l , – 20, dB m . 7. Set the r esolut[...]

Chapter 1 67 Making B asic Measurements Demodul ating F M Sign als Figure 1-57 Determi ning the Offset De mo dula te the F M Sig n a l 1. Connect an antenna to the a nalyzer INPUT . 2. Perform a fact ory preset by pressi ng Pre set , Factory Prese t (i f pres ent). 3. T une the anal yzer to a peak the peak of one of you r local FM broa dcast sig na[...]

68 Ch a pt er 1 Making Basic M easurements Demodu lating FM Si gnal s 12. A c tivat e sin g le swe e p b y pr essing Single . See Fi gur e 1 - 58 . Figure 1 -58 Demodulating a B roadcast Si gnal[...]

69 2 Maki ng Comple x Mea sur eme nts[...]

70 Ch a pt er 2 Making Complex Measurements What’ s in This Chapter What’ s in T his Chapte r Thi s ch ap ter p ro vi d e s in f o rm atio n fo r m aki ng co m pl ex me a sure m e n t s. The pro cedures c overed i n this c hapter are listed below . • “ Making Stimulus Res ponse Meas urements ” on p age 71 . • “ Ma kin g a R efle c tio[...]

Chapter 2 71 Making Comple x Measurements Making St im ulus Respo nse Measurements M aki ng S tim ulus R es p on se M ea s ur em en ts What Are Stimulus Re sponse Measureme nts? Stimulus response measurements requi re a so urce to sti mulate a device under tes t (DUT), a receiver to analyze the f requency resp onse characteristi cs of the DUT , and[...]

72 Ch a pt er 2 Making Complex Measurements Making St im ulus Respo nse Measurements Figure 2-1 T ransmission Measurement T est Setup 2. Perf orm a f actory preset by pressing Preset , Factory Preset ( i f p r es en t ) . 3. Se t the Y -A x is U n it s to dB m by pre ss in g AMPLIT UDE , Mo re, Y -Axi s Units, dBm . 4. Sinc e we ar e only i nterest[...]

Chapter 2 73 Making Comple x Measurements Making St im ulus Respo nse Measurements Figure 2 -2 T r ac king Generator Ou tput Power Activat ed 7. Put the sweep ti me of the a nalyz er into s timulus res ponse a uto coupl ed mo de by pre ss ing S weep , Swp Couplin g (SR). Auto coupl ed sweep times a re us u al ly mu ch fa ster fo r st im u lus res p[...]

74 Ch a pt er 2 Making Complex Measurements Making St im ulus Respo nse Measurements Figure 2-3 Decrease the Resolution Bandwidth to Improve S ensitivity 10. Y ou mig h t not ic e a de crea se in the di spl aye d am plit ud e as t h e resoluti on bandwidth i s decrea sed, ( if th e analyzer i s an E7402A, E74 03 A, E 740 4A, o r E7 405A ) . T hi s [...]

Chapter 2 75 Making Comple x Measurements Making St im ulus Respo nse Measurements 12.Reconnect the D UT to the analyzer . Note tha t th e units of the re fe re nce lev e l h av e c hang ed to dB, indi ca ti ng t hat t his is no w a rel ative measurement. Pre ss T race/View , More, N ormal ize, Norm Ref Posn to change t he normalized ref erence pos[...]

76 Ch a pt er 2 Making Complex Measurements Making St im ulus Respo nse Measurements T r acking Generator Unleveled Cond ition When using the trac king generator , the m e ssage TG unleve led may ap pe ar . Th e TG unl eve led mess age indica tes that the tracking gene ra to r so u rce po w er ( Source , Ampli tude ) c ould not be maintai ned at th[...]

Chapter 2 77 Making Comple x Measurements Making St im ulus Respo nse Measurements Measurements ar e made conti nuously , updating at the end of each swe e p. Thi s allows y ou to ma ke adj ust m ents a n d se e ch an g e s as t h ey happen. The si ngle s weep mode can also be used, p roviding time to stud y o r reco r d the da ta. The N dB band wi[...]

78 Ch a pt er 2 Making Complex Measurements Making St im ulus Respo nse Measurements NOTE T o reduc e rip ple s cau sed by so urce r etur n lo ss, use 10 dB (E 7401A ) o r 8 dB (a ll ot her model s) or greater tr acking g enerator output attenua tion. T r acking generat or output a ttenuati on is nor mally a f unction of the sourc e power sel ected[...]

Chapter 2 79 Making Comple x Measurements Making St im ulus Respo nse Measurements 1 1. The knob or the data entr y ke ys can be u sed to c hange the N dB value f rom − 3 dB to − 60 dB to m easure the 60 dB bandwid th of the fi lter . See Figu re 2 - 7 . Figure 2- 7 N dB Bandwidth Measurement at – 60 dB 12.Pr ess N d B Points (Off) to turn th[...]

80 Ch a pt er 2 Making Complex Measurements Making St im ulus Respo nse Measurements Figure 2-8 T ransmission Measurement T est Setup 2. Perf orm a f actory preset by pressing Preset , Factory Preset (if present). 3. Se t the Y -A x is U n it s to dB m by pre ss in g AMPLIT UDE , Mo re, Y -Axi s Units, dBm . 4. Se t the st ar t fre qu e n cy to 1 0[...]

Chapter 2 81 Making Comple x Measurements Making St im ulus Respo nse Measurements Figure 2- 9 T racking Generat or Output Power Activated in Log S weep 10.Put the sweep ti me of the a nalyzer i nto stimulus res ponse aut o coupl ed mo de by pre ss ing S weep , then Swp Co up ling (SR) . See Figu r e 2-9 . Auto coupled sweep t imes are usua lly muc[...]

82 Ch a pt er 2 Making Complex Measurements Making St im ulus Respo nse Measurements Figure 2-10 Normalized T race After Reconnecting DUT 14. Pre ss Ma rk er , De lt a Pa ir (R e f ), 10, MHz to p la ce the reference marker at the spec ifi ed cutoff freq uency . 15. Pre ss Delta P air (∆) , 2 0, MHz to p lace the s econd mar ker at the 20 MHz poi[...]

Chapter 2 83 Making Comple x Measurements Making St im ulus Respo nse Measurements Figure 2 -12 Minimum Stop Band At tenuation[...]

84 Ch a pt er 2 Making Complex Measurements Making a R eflection Calib ration M easurement Making a Reflec tion Calib ration Measurem ent The calibra tion standard for reflec tion measurements is usually a short circu i t conn e ct e d a t the re fe re n ce pl ane (t h e po in t at wh ic h the de v ice under tes t (DUT) will b e connected .) Se e F[...]

Chapter 2 85 Making Comple x Measurements Making a Reflect ion C alibrati on Measurement Reflection Calibration 1 . C o n n e ct the DU T t o th e di rect ion a l br id g e or c o u ple r a s s h o wn in Figu r e 2-13 . T ermina te the unc onnected p ort of the D UT . NO TE If possibl e, use a co u pl er or br idg e wi th t h e co rre ct t e st po [...]

86 Ch a pt er 2 Making Complex Measurements Making a R eflection Calib ration M easurement Figure 2-14 Sh or t Circuit Normal ized Measuring the Return Loss 1. Aft er calibrat ing the system with the above proc edure, reconnect the filter in pla ce of the s hort circui t without c hanging a ny analyzer setting s. 2. Use the marker to rea d return l[...]

Chapter 2 87 Making Comple x Measurements Making a Reflect ion C alibrati on Measurement Co nvert ing Retur n Los s to VSW R Re tur n l oss ca n be ex pr es s ed as a volt age s tan d in g w av e r at io (V SW R) value us ing the fol lowi ng table o r formula : Where: RL i s the measur ed return loss val ue. VS WR is so me time s state d as a rat i[...]

88 Ch a pt er 2 Making Complex Measurements Demodu lat ing and Listeni ng to an AM Signal Demodulati ng and List ening t o an AM S ignal The func tions listed in the menu und er Det/Demod allow y ou to de mod ul at e an d he ar si gna l inf or mat ion di spla yed on t he a nal yze r . Simpl y place a marker o n a signal of i nterest, a ctiv ate AM [...]

Chapter 2 89 Making Comple x Measurements Demodulat ing and Listeni ng to an AM Signal 7. Th e si gna l is dem o du la t e d at the m ark er po siti on o n ly for t h e duration of the demod time . Use the step keys, knob, or numeric keypad to c hange the d well tim e. F or example, press the s tep up key ( ↑ ) t o increa se the dwe ll time t o 2[...]

90 Ch a pt er 2 Making Complex Measurements Demodu lat ing and Listeni ng to an AM Signal 1 1. P ress Det/Demo d , Detector , Samp le t o set t he detec tor mode of the ana ly ze r to S ampl e. 12. Pre ss Det/Demod , Demo d , AM . Use the f ront pane l vol ume knob to co ntro l th e s peak er vo lum e. 13.Y o u can turn your analyzer into a % AM in[...]

Chapter 2 91 Making Comple x Measurements Demodulat ing and Listeni ng to an AM Signal Figure 2- 17 Continuous Demodulati on of an AM Signal[...]

92 Ch a pt er 2 Making Complex Measurements Demodu lat ing and Listeni ng to an AM Signal[...]