AN-1067: äœçžãã€ãºãšãžãã¿ã®é»åã¹ãã¯ãã«å¯åºŠïŒçè«ãããŒã¿è§£æãå®éšçµæ

ã¢ããªã±ãŒã·ã§ã³ã»ããŒã䜿çšäžã®æ³šæ
æ¬ã¢ããªã±ãŒã·ã§ã³ããŒãã®è±èªä»¥å€ã®èšèªãžã®ç¿»èš³ã¯ãŠãŒã¶ã®äŸ¿å®ã®ããã«æäŸããããã®ã§ããããªããžã§ã³ãå€ãå ŽåããããŸããææ°ã®å 容ã«ã€ããŠã¯ãå¿ ãææ°ã®è±èªçããåç §ãã ããã
ãªããæ¥æ¬èªçã®ã¢ããªã±ãŒã·ã§ã³ããŒãã¯åºæ¬çã«ãRev.0ãïŒãªããžã§ã³0ïŒã§äœæãããŠããŸãã

AN-1067: äœçžãã€ãºãšãžãã¿ã®é»åã¹ãã¯ãã«å¯åºŠïŒçè«ãããŒã¿è§£æãå®éšçµæ
ã¯ããã«
A/Dã³ã³ããŒã¿ãD/Aã³ã³ããŒã¿ã«äœ¿çšãããµã³ããªã³ã°ã»ã¯ããã¯ã®ãžãã¿ã¯éæå¯èœãªæ倧S/Næ¯ãå¶éããŸããïŒ ãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Integrated Analogto-Digital and Digital-to-Analog Converters by van de Plasscheãåç §ïŒãã®ã¢ããªã±ãŒã·ã§ã³ã»ããŒãã§ã¯äœçžãã€ãºãšãžãã¿ã«ã€ããŠæããã«ããŸããäœçžãã€ãºãšãžãã¿ã®é»åã¹ãã¯ãã«å¯åºŠã«ã€ããŠè°è«ãå±éããæéé åãšåšæ³¢æ°é åã®æž¬å®æè¡ã«ã€ããŠè¿°ã¹ãå®éšè£ 眮ã®å¶éã説æãããããæè¡ã«å¯Ÿããè£æ£ä¿æ°ãæäŸããŸãã玹ä»ããçè«ã¯çŸå®ã®äžçã®åé¡ã«å¯ŸããŠè¡ãããå®éšçµæã«ãã£ãŠè£ã¥ããããŸãã
æŠèŠ
é»åæ©åšã§äœ¿çšãããã¯ããã¯ãçºçããæè¡ã¯ãããããããŸããåè·¯ã¯R-Cåž°éåè·¯ãã¿ã€ããŒãçºæ¯åšãã¯ãªã¹ã¿ã«ãã¯ãªã¹ã¿ã«çºæ¯åšãå«ã¿ãŸããåè·¯æ¡ä»¶ã«ãã£ãŠã¯ãæ¯èŒçé«ãäœçžãã€ãºïŒãžãã¿ïŒã§ããæ¯èŒçå®äŸ¡ãªã¯ããã¯æºã䜿çšã§ããå¯èœæ§ããããŸãããããæè¿ã®ããã€ã¹ã¯ããåªããã¯ããã¯æ§èœïŒã€ãŸãããé«äŸ¡ãªïŒã®ã¯ããã¯æºãå¿ èŠãšããŸããé¡äŒŒããèŠæ±ãã³ã³ããŒã¿ã§ãµã³ããªã³ã°ãããä¿¡å·ïŒç¹ã«çŸåšã®é«æ§èœã³ã³ããŒã¿ã®ãã¹ãã«ä¿¡å·æºãšããŠäœ¿çšãããåšæ³¢æ°ã·ã³ã»ãµã€ã¶ïŒã®ã¹ãã¯ãã«çŽåºŠã«å¯ŸããŠããããŸãããã®åŸã®ã»ã¯ã·ã§ã³ã§äœçžãã€ãºãšãžãã¿ã®å®çŸ©ã瀺ããŸãã次ã«äœçžãã€ãºãšãžãã¿ããããã®åšæ³¢æ°é åè¡šçŸã«é¢é£ã¥ããæ°åŠçãªå°åºãè¡ããŸããäœçžãã€ãº/ãžãã¿ã®åšæ³¢æ°é åã§ã®è¡šçŸïŒåã¯é»åã¹ãã¯ãã«å¯åºŠïŒã¯äœçžãã€ãº/ãžãã¿ãçŽæ¥è¡šããŸããå°ãåºãããçè«ã¯A/Dã³ã³ããŒã¿ãšD/Aã³ã³ããŒã¿ã«çµã³ã€ããããŸããåçš®ã®ä¿¡å·ã枬å®ããããã«ã¹ãã¯ãã«ã»ã¢ãã©ã€ã¶ãšãªã·ãã¹ã³ãŒãã䜿çšããŸããæåŸã«çè«ã¯A/Dã³ã³ããŒã¿ïŒADCïŒAD9235ã«æœããå®éšã®çµæãšçµã³ã€ããããŸãã
å®çŸ©
äœçžãã€ãºãšãžãã¿ã«ã¯ããããã®è§£éããããŸãããã®ã¢ããªã±ãŒã·ã§ã³ã»ããŒãã§ã¯ãäœçžãã€ãºãšãžãã¿ã次ã®ããã«èŠå®ããŸãã
ãµã€ã³æ³¢ãèããŸãã
sin(Ït + A) (1)
ããã§:
Ï = 2Ïf.
fã¯ææã®åšæ³¢æ°.
Aã¯äžå®ã®äœçžãªãã»ããã
å³ 1.æ£èŠåãããµã€ã³æ³¢
äœçžãã€ãº
äœçžãã€ãºãä»»æã®é¢æ°ÎŠ(t) ãšå®çŸ©ãããšãåŒ1ã¯äžèšã®åŒã®ããã«è¡šããŸãã
å³ 2.äœçžãã€ãºãå«ããµã€ã³æ³¢ä¿¡å·
é¢æ°ÎŠ(t) ã¯Ïtã«é¢ä¿ããªãåšæ³¢æ°æåãäŸãã°ç±ãã€ãºãã·ã§ãããã€ãºã1/fãã€ãºïŒããªãã«ãŒãã€ãºïŒãã§æ§æãããå¯èœæ§ããããŸãããããã»ãšãã©ã®å Žåã¯ãããã¯ã¬ãŠã¹ã»ãã€ãºãšããŠã¢ãã«åãããŸããïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Frequency Synthesizers Theory and Design Third Edition by Manassewitschãåç §ïŒ
åæ§ã«ããµã³ãã«ã»ã¯ããã¯ã¯æ¬¡åŒã®ãããªåºå®ããæéééÏã§ç¹°ãè¿ãç«ã¡äžãããç«äžãã®ããåšæçãªç©åœ¢æ³¢ãšèããããŸãã
å³ 3.ãµã³ããªã³ã°ã»ã¯ããã¯
ãžãã¿
ãžãã¿ã¯åºå®ããééÏã«è¿œå ãããæéå€åÎ(t) ãšããŠå®çŸ©ãã次åŒã§è¡šããŸãã
å³ 4.ãžãã¿ã®ãããµã³ããªã³ã°ã»ã¯ããã¯
åæ§ã«ããŠãÎ(t)ã¯äžè¬çã«ã¬ãŠã¹ã»ãã€ãºãšããŠç¹æ§åãããŸãã
å³ 5.çºæ¯åšã®ã·ã³ã°ã«ã»ãµã€ããã³ãã®ãã€ãºã»ã¹ãã¯ãã«
5 kHz以äžã§ã¢ã¯ãã£ãã»ããã€ã¹ãé«åšæ³¢ã§å¶éããããŸã§ã®åšæ³¢æ°ã«ããããã€ãºè§£æã¯åçŽã§ãã5 kHz以äžã®ãã€ãºã¯ã·ã§ãããã€ãºãç±ãã€ãºãã倧ãããªããŸãããã®ãã€ãºã¯åšæ³¢æ°ã«éæ¯äŸãã1/fãã€ãºãšããŠç¥ãããŠããŸããå³5ã¯çºæ¯åšã®äžè¬çãªãã€ãºã»ã¹ãã¯ãã«ã瀺ããŠããŸããïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Manassewitsch ãåç §ïŒ
é»åã¹ãã¯ãã«å¯åºŠ
æéé åä¿¡å·ã¯ããŒãªãšå€æãéããŠåšæ³¢æ°é åã«çŽæ¥çãªé¢ä¿ããããŸããïŒã¬ãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Discrete-Time Signal Processing by Oppenheimãåç §ïŒãªãã¡ã¬ã³ã¹ããŒãªãšå€æã¯ä¿¡å·ã®æ¯å¹ ãšäœçžã®ã¹ãã¯ãã«ãšèŠãªãäºãåºæ¥ãŸããä¿¡å·ã®é»åãåšæ³¢æ°é åã§è¡šç€ºããäºãã§ããŸããé»åã¹ãã¯ãã«å¯åºŠåã¯é»åã¹ãã¯ãã«ã¯æ¬¡ã®åŒã«ãã£ãŠäžããããŸãã
ããã§Y(Ï) ã¯y(t)ã®ããŒãªãšå€æã§ãã
âå®çŸ©âã®ã»ã¯ã·ã§ã³ã§åã«è¿°ã¹ãããã«ãΊ(t)ã¯ä»»æã®æãŸãããªãä¿¡å·ãšèããããŸãããã®è§£æãç°¡ç¥åããããã«ãΊ(t)ãåäžåšæ³¢æ°ã«èšå®ããŸãã次åŒãèããŸãã
ããã§åŒ2ã¯æ¬¡ã®ããã«ãªããŸãã
çµæã¯ãäœçžå€èª¿ãããä¿¡å·y(t)ãšãªããæ倧äœçžåå·®ã¯åšæ³¢æ° fmïŒ Ïm = 2ÏfmïŒã§ÎždïŒã©ãžã¢ã³ïŒã§ããåãªãã»ããã¯ãŒãïŒA=0ïŒã§ãã
ã€ã³ãã»ã¢ã³ã¬ãŒã®å±éåŒïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Concise Encyclopedia of Mathematics by Weissteinãåç §ïŒã次ã«ç€ºããŸãã
åã¯
ãªã€ã©ãŒã®çåŒã䜿çšãæžãçŽããšäžèšã®åŒãåŸãããŸãã
ãããŠ
ããã§JnïŒZ)ä¿æ°ã¯ç¬¬äžçš®ããã»ã«é¢æ°ã§ãã
äžè§é¢æ°ã®çåŒãçšããŠãåŒ7, åŒ8, åŒ10, åŒ11ãæžããªãããšäžèšã®åŒãåŸãããŸãã
åŒ12ããy(t)ã¯ãã£ãªã¢åšæ³¢æ°fcã§1次ããã»ã«æåãããããã£ãªã¢åšæ³¢æ°ããå€èª¿åšæ³¢æ°fmã®åæ°ãªãã»ããããåšæ³¢æ°ã§ããã»ã«éã¿ä»ãä¿¡å·ãååšããäºãããããŸãã
fc = 32,768 Hzã§fm = 1024 Hzãäœçžåå·®ã500mrad(mradã¯ããªã©ãžã¢ã³ïŒã®å Žåã®é¢æ°y(t) ã®é»åã¹ãã¯ãã«å¯åºŠSyy(Ï)ãå³6ã«ç€ºããŸãã
å³ 6.é»åã¹ãã¯ãã©ã å¯åºŠãSyy(Ï)
å³6ã¯äžèšã®åŒã®ã°ã©ãã§ãã
Syy(Ï) = Y(Ï) Ã Yâ(Ï)
ããã§Y(Ï) ã¯y(t)ã®ããŒãªãšå€æã§ãã
Syy(Ï) ã¯åšæ³¢æ°fã§ã®é»åã®å€§ãããè¡šããŸããåäžåšæ³¢æ° fmã®ã¿ã«ããå€èª¿ãããä¿¡å·y(t)ã®é»åã¹ãã¯ãã«å¯åºŠã¯fc ãš fm ã§ããã»ã«é¢æ°ã®äºä¹ã®å€§ããã®åšæ³¢æ°æåããããŸãã
é«æ¬¡æ°ã®ããã»ã«ä¿æ°ã»ã©éåžžã«æ©ãæžè¡°ããŸãã察æ°é»åç®çã§ããã°åºããã€ãããã¯ã»ã¬ã³ãžã衚瀺ã§ããã®ã§ã倧ããªãã£ãªã¢æåãšåãã°ã©ãäžã§ããé«æ¬¡ã®æåãè¡šãããšãã§ããŸããSyy(Ï)ã®å¯Ÿæ°ã¯æ¬¡ã®åŒã«ãªããŸãã
ãããŠå³7ã«ç€ºããŸãã
å³ 7.é»åã¹ãã¯ãã©ã å¯åºŠã®å¯Ÿæ°ãSyy(Ï)
ããã§ä»ã®é ãæ確ã«èŠããããã«ãªããŸãããäœçžåå·®ãå¢ããšããã£ãªã¢åšæ³¢æ°ã®å€§ãããæžå°ããå€èª¿é ã®å€§ãããå¢ããŸããäœçžåå·®ã500 mradã®å Žåããã£ãªã¢é»åã¯çŽ 12%æžå°ããŸãã
äœçžåå·®ãå°ããå ŽåãΞd << 1 rad, J0(Ξd) â 1, J1(Ξd) âΞd/2, 㧠J2(Ξd) ⊠Jn(Ξd) â 0ïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Manassewitschãåç §ïŒ
äœçžåå·®ããŒãã«è¿ã¥ããšããã£ãªã¢é»åã¯100%ã«è¿ã¥ããŸããããã«ãäœçžåå·®ãå°ãããšå€èª¿é ã®äžã«åæ£ããããã£ãªã¢åšæ³¢æ°é»åã®å²åãããå°ãããªããŸããçµå±ãã®äºã«ããΊ(t)ã®é»åãããæ£ç¢ºã«è¿äŒŒããå€èª¿é ã®åèšã«ãªããŸãã
ããã»ã«é¢æ°ã¯æ¬¡ã®é¢ä¿ããããŸã:
äœçžåå·®ãå°ããæã®ç¹åŸŽãå©çšãããšãΊ(t)ïŒã·ã³ã°ã«ããŒã³ã»ãµã€ã³æ³¢å€èª¿ïŒã®äºä¹å¹³åå¹³æ¹æ ¹ (rms) é»åã¯ãããã次åŒã§è¡šããŸãã
åã¯
äœçžåå·®ãårmsæ¯å¹ ã«æç®ããŠè¡šç€ºã§ããŸãã
äŸ 1
äœçžå差Ξdã100mradã®å Žå
Prms â 1 â J0(0.1)2
Prms â 1 â 0.9950094
Prms â 1 â 0.0049906
Arms â 0.0706444
ãã®çµæããµã€ã³æ³¢ä¿¡å·ã®é»åãšæ¯ã¹ãŸãã
e(t) = Asin(Ït)
Pe = A2/2
A = 0.1ãšãããšãrmsé»åãPe=0.0005ã§ãArms = A/â2= 0.0707107ãšãªããå°ããªäœçžåå·®ã®å Žåãå€èª¿é ã®åèšã¯rms é»åãè¯ãè¿äŒŒããå€ã«ãªãäºã確èªã§ããŸãã
ãã®è°è«ã¯ãã£ãšè€éãªå€èª¿ä¿¡å·ã«ãå±éã§ããŸãããã£ãšè€éãªå€èª¿é¢æ°ã¯ïŒäºãã«ã¹ãã¯ãã«ã«åœ±é¿ãåãŒãïŒããããã®åšæ³¢æ°é ã®éãåãããšããŠåãæ±ããŸããé»åã¹ãã¯ãã«å¯åºŠã¯è¿œå ã®é ãæã€ã®ã§ããããåèšããŠå€èª¿ä¿¡å·ã®rmsé»åãè¡šããŸããæ¯å¹ ãå°ããå Žå(Ξd <<1 rad)ãä»»æã®é¢æ°ÎŠ(t)ã®rms é»åã¯æ¬¡åŒã§äžããããŸãã
åŒ18ã¯äœçžå€èª¿ããä¿¡å·ã®rmsé»åã¯ãã¹ãŠã®æåã®åèšããåºæ¬æ³¢ïŒåã¯ãã£ãªã¢åšæ³¢æ°ïŒã®é»åãæžç®ããå€ã«çãããªãäºãè¿°ã¹ãŠããŸãã
ãµã€ã³æ³¢ä¿¡å· y(t)ã®å Žåãäœçžå€èª¿ã¯å¯Ÿç§°ã®é»åã¹ãã¯ãã«å¯åºŠãçãã®ã§ãrmsé»åãå次åŒã§äžããããŸãã
ããã¯ã·ã³ã°ã«ã»ãµã€ããã³ã枬å®æè¡ãšåŒã°ããŠããŠéåžžã«ãŒãã»ãã«ããããã®å€ã§ããïŒã¬ãã¡ã©ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Manassewitschãåç §ïŒ
rmså€èª¿ã¯ããã€ãã®æ¹æ³ã§è¡šããŸãã
åŒ20ã¯äœçžåå·®ã床ã§è¡šç€ºããŸãã
äœçžãã€ãºãæéãžãã¿ãšé¢é£ã¥ããããã«ã次ã®åŒã䜿çšããŸãã
ãã㧠Ï= 1/fc ã¯äœçžåå·®ãæéã§è¡šããŸãã
äŸ2-äœçžãã€ãº
ãã€ãºã®å€ããµã€ã³æ³¢ãçæ³ã¯ããã¯ã§ãµã³ããªã³ã°ããå ŽåãèããŸãã
y(t) = sin(Ïct + N(t))
ããã§:
Ïc = 2Ï26,2144.
N(t)ã¯æšæºåå·®Ï = 10 mradã®ã¬ãŠã¹ã»ãã€ãºã§ãã
圢æããä¿¡å·ãïŒç§ããã4çŸäžã®ãµã³ãã«æ°ã§15msã®éãµã³ããªã³ã°ãã65,000ã®ãµã³ãã«ãåŸãŸããé»åã¹ãã¯ãã«å¯åºŠã®å¯Ÿæ°ã0 dBã§æ£èŠåããŠãå³8ã«ç€ºããŸãã
å³ 8.260 kHz, 10 mradäœçžãã€ãº
åºæ¬æ³¢ã¯çŽ260 kHzã§ãå šã¹ãã¯ãã«ã«æž¡ã£ãŠãã€ãºããããŸãã
åŒ 18ã®é¢æ£åœ¢åŒã䜿ã£ãŠ
åºæ¬æ³¢ã§ã®é»åã¯å«ãŸãã«ã0ãããã€ãã¹ãåšæ³¢æ°ãŸã§ã®å šåšæ³¢æ°ã§ã®é»åã®å€§ãããåèšããŸãããã®çµæã®ãã€ãºé»åã¯
Prms = 1.0017 Ã 10â4
rmsæ¯å¹ ã¯Arms â 0.010008 radã§ãã
äžäžèŽå0.008 mradã¯10 mradã®rmsãã€ãºæ¯å¹ ããæ°ã±ã¿å°ãããéåžžã«è¯å¥œãªè¿äŒŒãåŸããäºãããããŸãã
äœçžåå·®ãΊ(t0)=0ã®å Žåå ¥åä¿¡å·ã®æ¯å¹ ã¯æét0ã§A0ã§ããäœçžåå·®ãΊ(t0) = ÎΊmradã§ãã€ãºã®å€ãå ¥åä¿¡å·ã®å Žåãæét0ã§æ¯å¹ ãAΊã«ãªããŸããåæ§ã«ãæéå€äœ t1 = t0 + Ît,ã§ãµã³ããªã³ã°ãããå ¥åä¿¡å·ã¯æ¯å¹ AÏã«ãªããŸãã
å³ 9ã¯åãæ¯å¹ , AÎãçããæéåå·®Îtãšäœçžåå·®,ÎΊãååšããäºã瀺ããŠããŸããäºå®äžãžãã¿Ît, rmsæéåå·®ã«çããrmsæ¯å¹ ã®äœçžåå·®ÎΊã¯åæ§ã®çµæã«ãªããŸãã
å³ 9.ãµã€ã³æ³¢ä¿¡å·ã®ã¿ã€ãã³ã°ãšäœçžå€äœã®åœ±é¿
äŸ3ïŒãžãã¿
äŸ 2ã§ã¯ãäœçžãã€ãºN(t)ã®ä¿¡å·ã®é»åã¹ãã¯ãã«å¯åºŠã¯ã¬ãŠã¹ååžã«ãªããæšæºåå·®Ï = 10 mradã§ããä»åºŠã¯ã¬ãŠã¹ã»ãã€ãºÎ·(t)ã®ãããžãã¿ã®å€ãã¯ããã¯ã§ãµã³ããªã³ã°ããä¿¡å·ãèããŸããåŒ21ã¯äœçžãã€ãº10 mradãšåãå¹æãçããrmsãžãã¿ã決ããããã«äœ¿çšããäºãã§ããŸããçµæã®åºåã¯
y(t) = sin(Ïc(t + η(t)))
ããã§ãã£ãªã¢åšæ³¢æ°ã¯åã³260 kHzã§ãη(t)ã¯æšæºåå·®6.0713 nsã®ã¬ãŠã¹ã»ãã€ãºã§ãã
圢æãããä¿¡å·ãïŒç§ããã4M ã®ãµã³ãã«æ°ã§15msã®éãµã³ããªã³ã°ããŠã65ïœã®ãµã³ãã«ãåŸãŸããé»åã¹ãã¯ãã«å¯åºŠã®å¯Ÿæ°ã0 dBã«æ£èŠåããŸãã
å³ 10.äœçžãã€ãºã§å€èª¿ãã260HzããŒã³ã4 MSPSã§ãµã³ããªã³ã°ããæã®65k FFT
åŒ22ã䜿çšããåºæ¬æ³¢ã®é»åã¯å«ãŸãã«ã0ãããã€ãã¹ãåšæ³¢æ°ãŸã§ã®å šåšæ³¢æ°ã§ã®é»åã®å€§ãããåèšããŸãããã®çµæã®ãã€ãºé»åã¯
Prms = 1.0031 Ã 10â4
ãããŠrmsæ¯å¹ ã¯
Arms = 0.010016 rad
çµæãåŒ21ã«æ¿å ¥ãäžã®åŒãåŸãŸãã
Atrms = 4.86455 Ã 10â8s or Atrms â 49 ns
ãã®çµæã¯äŸ2ã§åŸãããçµæãšäžèŽããŸãã
ã¯ããã¯ãå ¥åä¿¡å·ãå€èª¿ããŠããåºåž¯åãã€ãºã¯åæ£ããããã€ãºã®é»åã¹ãã¯ãã«ã«ãªããŸããåå ¥åä¿¡å·ãã¯ããã¯ãå€èª¿ãããã€ãºã¯ãã£ãªã¢åšæ³¢æ°äžå¿ã«å¯Ÿç§°ã®ãã€ãºã«ãªããŸããé»åã¹ãã¯ãã«å¯åºŠã¯ç¹å®ã®åšæ³¢æ°æåãããã¯åšæ³¢æ°ç¯å²ã«é¢é£ããäœçžãã€ãºããžãã¿ã決ããããã«äœ¿çšããäºãã§ããŸãã倧ããªå¯Ÿç§°é ã¯ä¿¡å·ãããŠ/åã¯ã¯ããã¯ãå€èª¿ããŠããç¹å®ã®åšæ³¢æ°ã匷調ããŠãããšèããããŸããç¹å®ã®åšæ³¢æ°ã«é¢é£ããrmsé»åã¯é»åã¹ãã¯ãã«å¯åºŠããçŽæ¥åŒãåºãäºãã§ããŸããåšæ³¢æ°ã®ç¯å²ã«ã€ããŠã¯ãäžèšã®åŒã䜿çšã§ããŸãã
åã¯ã·ã³ã°ã«ã»ãµã€ããã³ãã«ã€ããŠã¯ã
ã³ã³ããŒã¿ãžã®å¿çš
çŸåšã®é«éã³ã³ããŒã¿ã¯12 ããã以äžã®å解èœã§100MSPS以äžã®ãµã³ããªã³ã°ã»ã¬ãŒãããããŸããïŒSFDRïŒã¹ããªã¢ã¹ããªãŒã»ãã€ãããã¯ã»ã¬ã³ãžã100 dBc以äžããã°ã70 dBc以äžã®S/Næ¯ïŒSNR)ã¯ãåžžæéæãããŸããD/Aã³ã³ããŒã¿ïŒDAC)ã®æ§èœã¯ãµã³ããªã³ã°ã»ã¯ããã¯ã®ãžãã¿ã«çŽæ¥åœ±é¿ãããŸãããã€ãºã®å€ãã¯ããã¯ã䜿ã£ãŠãµã³ããªã³ã°ããŠããDACã䜿ã£ãŠçæããã波圢ã¯äœçžãã€ãºããã£ãä¿¡å·ã«ãªãå¯èœæ§ããããŸããADCã¯ãµã³ããªã³ã°ã»ã¯ããã¯ãšå ¥åä¿¡å·ã®äž¡æ¹ã®ãã€ãºã«åœ±é¿ãããŸããäŸ 3ãŒãžãã¿ã®ã»ã¯ã·ã§ã³ã§å°ãããçµæã¯ã³ã³ããŒã¿ã«é©çšãããŸãã
çµæãADC ã«çµã³ã€ããå³11 ã«ç€ºãåè·¯ãæ€èšããŸãã
å³ 11.ADCæ©èœãããã¯å³
ADCã¯ç¬æ tïŒåšæÏãããïŒã«å ¥åä¿¡å·Asin(Ït)ããµã³ããªã³ã°ããNãããã®éååãããåºåãçããŸãã
å ¥åä¿¡å·ã®ãã€ãºãšãµã³ããªã³ã°ã»ã¯ããã¯ã®ãã€ãºã¯ç¬ç«ããŠãããšä»®å®ãããšãç·åãã€ãºã¯2ä¹åå¹³æ¹æ ¹ã§äžããããŸãããããã€ãºã®å€§ãããããªã倧ãããšãã³ã³ããŒã¿ã®æ倧æ§èœã«åœ±é¿ãåãŒããŸãã
éååãã€ãºã¯ãããæ°ã«çŽæ¥æ¯äŸããŸããåºåããŒã¿ã»ãµã³ãã«ãADCç¯å²å ã«ãã€æ倧誀差ã¯æäžäœãããå解èœQN ã 2ã§å²ç®ããå€(QN/2)ã§ããïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®van de Plassche, Oppenheim, and Delta-Sigma Data Converters Theory Design and Simulation by Norsworthy, Schreier, and Temesãåç §ïŒèª€å·®ã¯ãµã³ããªã³ã°ãããä¿¡å·ã«ãã£ãŠå®ãŸããŸããã©ã³ãã ã«å€åããŠããä¿¡å·ã®å Žåã¯ãéåå誀差ã¯ç¡çžé¢ã§ã±QN/2.以å ã®ä»»æã®å€§ããã«ãªããŸãã誀差ãçµ±èšçã«ãµã³ããªã³ã°ãããä¿¡å·ã«å¯ŸããŠç¬ç«ããŠããã°ãéæå¯èœãªæ倧SNRã¯æ¬¡åŒã§ç€ºãããšãã§ããŸãã
12ãããã³ã³ããŒã¿ã®å Žåãçè«çãªæ倧SNRã¯çŽ74 dBcã§ãã74 dBcã®ç·åéååãã€ãºé»åã¯æ¬¡ã®å€ã«çžåœããŸãã
Pqn â 10â7.4
Pqn â 39.8107 Ã 10â9
ãã¹ãè£ çœ®ã¯è¢«ãã¹ãã»ã³ã³ããŒã¿ãã10 dBåªããŠããäºãæãŸããŸãã12ãããã³ã³ããŒã¿ããã¹ãããå ŽåãèŠæ±ããããã¹ãè£ çœ®ã®ãã€ãºé»åã¯84 dBcã§ãã
Pqn â 10â8.4
Pqn â 3.98107 Ã 10â9
åŒ 17ãçšããŠãã®ãã€ãºé»åãrmsäœçžåå·®ã«é¢é£ã¥ããäºãã§ããŸãã
Arms â 0.0631 mrad
å ¥åä¿¡å·10 MHz ã®å Žåãããã¯äžèšã®ãžãã¿ã«çžåœããŸãã
Atrms â Ï Ã âPrms/2
Atrms â 100 Ã 10â9 (â3.98107 Ã 10â9)/2Ï
Atrms â 1.004 Ã 10â12 sec
è¡š1ã¯ã³ã³ããŒã¿ã®éååãã€ãºã«ããSNRãªãããå€ãšçžåœããäœçžãã€ãºrmsæ¯å¹ ãäžèŠ§ã«ããŠããŸãã
ãããæ° | çè«çãªSNRãªããã (dB) | 察å¿ããäœçžãã€ãº (mrad) | ãã¹ãè£ çœ® | |
10 dB (mrad) | 6 dB (mrad) | |||
8 | 49.96 | 3.177 | 1.005 | 1.592 |
10 | 62 | 0.794 | 0.251 | 0.398 |
12 | 74.04 | 0.199 | 0.063 | 0.1 |
14 | 86.08 | 0.0497 | 0.16 | 0.025 |
16 | 98.12 | 0.0124 | 0.004 | 0.006 |
è¡š1ã«ã¯åãã¹ãè£ çœ®ã®äœçžãã€ãºrmsæ¯å¹ ããã³ã³ããŒã¿ãã 10 dB ã 6 dB åªããå€ã§ç€ºããŠãããŸããå Žåã«ãã£ãŠã¯ã³ã³ããŒã¿ãã6 dBåªãããã¹ãè£ çœ®ã§ã蚱容ãããŸãïŒç¹ã«10 dBãåŸãã®ãå°é£ãªå ŽåïŒã
åŒ 21ã䜿çšããäºã«ããç䟡ã®ãžãã¿æ¯å¹ ãç°¡åã«åŸãããŸãã
ã³ã³ããŒã¿ã®SNRæ§èœã¯äžè¬çã«é»åã¹ãã¯ãã«å¯åºŠã䜿çšããŠæ±ºå®ãããŸãããµã³ããªã³ã°åšæ³¢æ°ãšããŒã¿ã»ãµã³ãã«æ°ãçŽæ¥åšæ³¢æ°å解èœã決å®ããŸãã32 MHzã§ãµã³ããªã³ã°ããã³ã³ããŒã¿ã«å¯ŸããŠ4k FFTã¯åšæ³¢æ°8kHzãŸã§èœãšããŠå解ã§ããååãªããŒã¿ãèç©ããŸããããªãã¡é»åã¹ãã¯ãã«å¯åºŠã¯8 kHz ééã§æ å ±ã衚瀺ããŸããå8KHzãã³ã¯ãã®éé以å ã®åšæ³¢æ°ã®é»åãšãã®ééã«æãè¿ãããåšæ³¢æ°ã®é»åã®åèšã«ãªããŸãããã£ãªã¢ãã1 kHzã«ååšããæåã®å€§ããã¯ãããã®æ¡ä»¶äžã§ã¯æ±ºå®ãããŸãããåšæ³¢æ°å解èœã¯ãã倧ããªFFTã«ããäºã«ããæ¹åãããŸãã1/f ãã€ãºã®ãããªäœåšæ³¢äœçžãã€ãºãå解å¯èœã§ã32 MHzã§ãµã³ããªã³ã°ããã³ã³ããŒã¿ã®å Žåã1M FFT ã«ããäºã«ãã32 Hz ãŸã§å解å¯èœã§ãã
äŸ 1
20 psã®ã¯ããã¯ã»ãžãã¿ã«ãã£ãŠ1ç§éããã32Mãµã³ãã«æ°ã§ãµã³ããªã³ã°ãã12ãããADCã«å¯ŸããŠãå ¥åä¿¡å·ã¯ 2 kHz, 1 mradäœçžãã€ãºæåãš 0.5 mradã®ã¬ãŠã¹äœçžãã€ãºãå«ã4MHzãšããŸãããã®èšå®ã䜿çšããŠ4kãµã³ãã«ãååŸãããšãå³12ã«ç€ºããé»åã¹ãã¯ãã«å¯åºŠãåŸãããŸãã
å³ 12.å€èª¿ããã4 MHzããŒã³ã32 MSPSã§ãµã³ããªã³ã°ããæã®4k FFT
åŒ22 ã䜿çšãããšãã€ãºé»åã6.628â7 W ãšèšç®ããŸãããããçè«å€ã¯ïŒãžãã¿,äœçžãã€ãºãéååãã€ãºã®RSSãšãªãïŒ5.677â7W ã®ã¯ãã§ãã
æ¡å€§å³ïŒå³13åç §ïŒã¯åºæ¬æ³¢åšèŸºã§ã¹ã«ãŒãç¶ã«åºãã£ãŠããäºã瀺ããŠããŸããåšæ³¢æ°å解èœã¯8 kHzã§ã2kHzå€èª¿é ã¯åºæ¬æ³¢ãšåšèŸºã®ãã³ãšçµã³ã€ããŠããŸãã
å³ 13.äœãã³å解èœã«ãã£ãŠã¹ã«ãŒãç¶ã«ãªã4 MHzåºæ¬æ³¢ã®æ¡å€§å³
å³ 14.å€èª¿é ã瀺ããŠããããé«å解èœã®FFT
65kFFTã䜿ããšãåšæ³¢æ°ã¯500 HzãŸã§å解å¯èœã§ãã2ã€ã®æ°ãã察称é ãèŠãããŸãããããã¯äœçžå€èª¿ãæå³ããŸãããããã®é ãç©åãããã€ãºé»åã«å ç®ããããšããã€ãºé»åã5.696â7 Wãšèšç®ããŸãã
ãã¹ãè£ çœ®
äœçžãã€ãºãšãžãã¿ã¯ãªã·ãã¹ã³ãŒãã䜿çšããŠæéåå·®ãšããŠèŠ³å¯ããããã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã䜿çšããŠåšæ³¢æ°ã¹ãã¯ãã«ãšããŠèŠ³å¯ããäºãã§ããŸãã
ãªã·ãã¹ã³ãŒã
ãªã·ãã¹ã³ãŒãã¯2çš®é¡ã«åããããšãã§ããŸã: ãªã¢ã«ã¿ã€ã ãšãµã³ããªã³ã°ïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®XYZs of Oscilloscopes by Tektronixãåç §ïŒ
ãªã¢ã«ã¿ã€ã ã»ãªã·ãã¹ã³ãŒãã¯åäžããªã¬ãŒã»ã€ãã³ãã§ãµã³ãã«ã»ã¹ããªãŒã ããšãããŸãããµã€ã¯ã«éåå·®ã¯åºå®ããããããå€ã§ã®ããŒã¿ããåãåºãããŸãããã®æ¹æ³ã¯ãªã·ãã¹ã³ãŒãã®æééé枬å®ç²ŸåºŠãšãã®å éšãžãã¿ã«ãã£ãŠå¶éãããŸãããã¯ãããã¯ã¹ TDS7404ã¯ç²ŸåºŠÂ±8.5 psãæšæºãã€ãºã»ããã¢1.5 ps rmsãšèŠå®ãããŠããŸãããã¯ãããã¯ã¹ TDS694Cã¯ç²ŸåºŠÂ±15 psã§ãã粟床ã®åäžã¯ãªã·ãã¹ã³ãŒãã®åçŽå解èœãšãä¿¡å·åŠçã«é·ãã¬ã³ãŒãé·ãå«ãããšã«ãããçµ±èšçæ段ã§éæã§ããŸãããã¯ãããã¯ã¹ã¯åŸè ã®æè¡ã䜿ã£ãŠ1.5 psãžãã¿æž¬å®ç²ŸåºŠã謳ã£ãŠããŸããïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Analyzing Clock Jitter Using Excel and Understanding and Performing Precise Jitter Analysis by Tektronixãåç §ïŒ
ãµã³ããªã³ã°ã»ãªã·ãã¹ã³ãŒãã¯åããªã¬ãŒã§ã®å ¥åããŒã¿ã环ç©ããŸããæéåå·®ãåŸãã®ã«ãå ¥åä¿¡å·ã¯ç¹°ãè¿ããµã³ããªã³ã°ãããæ°Žå¹³æé¢ã§ç¹ååžãååŸããŸããæ°Žå¹³ç®çãšåçŽç®çã¯æž¬å®ãããæéåå·®ã®å€§ããã«ãã調æŽãããŸãããã®æéå差枬å®æ¹æ³ã¯äž»ã«ããªã¬ã»ãžãã¿ã®å€§ããã«ãã£ãŠå¶éãããŸãããµã³ããªã³ã°ã»ãªã·ãã¹ã³ãŒãã®æ¹ãæééé粟床ã«ã€ããŠã¯ã¯ããã«åªããŠãããŸãããããŠããã«éèŠãªäºã§ããããµã³ããªã³ã°ééã¯10 fsçšåºŠãšäœããªã£ãŠãããŸãããã¯ãããã¯ã¹11801Cã®æééé粟床ã¯1 ps + 0.0004% à (position) ã§ããªã¬ã»ãžãã¿ã¯æšæº1.1 ps rmsã§ããTDS8000Bãã¯ãããã¯ã¹ã»ãµã³ããªã³ã°ã»ãªã·ãã¹ã³ãŒãã®ããªã¬ã»ãžãã¿ã¯800 fsãšèŠå®ãããŠããŸããïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®äžã®Automatic Measurement Algorithms and Methods for the 8000 Series Sampling Oscilloscopes by Tektronixãåç §ïŒ
ã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶
ã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã¯ä¿¡å·ããã®åšæ³¢æ°æåã§è¡šç€ºããŸããã¹ãã¯ãã«ã¯èšå®ãããå解èœåž¯åå¹ ïŒRBW)以å ã®äžé£ã®æž¬å®å€ã衚瀺ããŸããã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã¯ä¿¡å·ã®é»å§ãããŠ/ãããã¯é»åããªãã¢åã¯å¯Ÿæ°è¡šç€ºã§è¡šããŸããä¿¡å·ã®é»åã®èŠ³å¯ã¯ããŒãªãšè§£æã§åŸãããé»åã¹ãã¯ãã«å¯åºŠã®ã°ã©ãã«é¡äŒŒããŠããŸãã
é»åæ©åšã®äžã®ã©ã³ãã ãã€ãºã¯ã¬ãŠã¹ååžã§ããããæ ãã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã®RBWïŒå解èœåž¯åå¹ ïŒä»¥å ã®ãµã³ãã«ã¯ç¢ºçååžãæã£ãŠããŸãïŒãããããµã³ãã«ã¯åçŽãªå€§ããã§è¡šç€ºãããŸããã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã¯å®éã«ã¯åçž(I) ãšçŽäº€ (Q)æåã§æž¬å®ããŸãïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Spectrum Analyzer Measurements and Noise by Hewlett Packard ãåç §ïŒãI/Qæåããä¿¡å·ã®å€§ãããšäœçžãåŸãããŸãããã³ããã¹ãééãããã€ãºã¯IãšQã®äž¡æ¹ã®æåãç¬ç«ããã¬ãŠã¹ååžã«ãªããŸãã
倧ããã¯ãšã³ãããŒãæ€åºåšã§åŸããã次ã®åŒã§äžããããŸãã
ãã€ãºã®å€§ããã¯å³15 ã®äžå¿åšèŸºã«åå¿åã圢æããŸããååã®äžã®æ°ããã€ãºã®å€§ããã®ååžã«ãªããŸãããã€ãºã»ãšã³ãããŒãã®ååžé¢æ°ã¯å®éã¬ã€ãªãŒååžã§ããïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Probability, Random Variables, and Stochastic Processes by Papoulisãåç §ïŒ
å³ 15.ã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã»ãšã³ãããŒãæ€åºåšå ¥åååž
確çå¯åºŠé¢æ°ãå€ãã°ã次ã®åŒã䜿ã£ãŠé»å§ãšã³ãããŒãã®å¹³åã決å®ããäºãã§ããŸãã
å¹³åé»åã¯æ¬¡ã®åŒã§äžããããŸãã
é»åãèšç®ããã®ã«ãå¹³åãšã³ãããŒãé»å§ãäºä¹ããRã§å²ç®ããŠãåŒ29ãšåãçµæã«ã¯ãªããŸãããçµæã¯1.05 ãããå°ãããªããŸãã
ã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ããã®å¯Ÿæ°è¡šç€ºã¢ãŒãã§äœ¿çšããæã¯ããã«èæ ®ããªããã°ãªããªãäºããããŸãã察æ°è¡šç€ºã¢ãŒãã§ã¯å ¥åä¿¡å·ã¯å¯Ÿæ°ã¢ã³ããééããŸããåŸã£ãŠãã®å€ã察æ°å€æããã確çå¯åºŠé¢æ°ã®çµæã«ãªããŸãããã®äžãã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã¯å¯Ÿæ°ã®å¹³åã衚瀺ããŸããçµå±å¯Ÿæ°åŠçã«ãããã€ãºã«å¯Ÿããå¿çã¯2.51 dBäœãçµæã«ãªããŸãã
蚌æ
äžèšã¯ãã€ãºã®2.51 dBäœãå€ã«ãªãããšã®èšŒæã§ãã
å·Šå³äž¡åŽã®å°é¢æ°ããšããŸãã
ã©ã€ããããåã䜿ããšïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Weissteinãåç §ïŒ
åã¯ãããªã¹ã«ããïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ãåç §ïŒ
äžèšã®åŒãåŸãŸãã
çµæã¯å ¥åãšã³ãããŒãã®å¯Ÿæ°é»åã®ç¢ºçååžã§ãã
次ã«å¹³å察æ°é»åã¯æ¬¡åŒã§äžããããŸãã
ã©ã€ããããåïŒãšãããªã¹ïŒãã
fy(y)dy = fx(x)dx
åãã®ç©åã¯1ã«ãªããŸãããªããªãããã¯åã«ã©ã€ãããã確çå¯åºŠã®ç©åã ããã§ããããã§2çªç®ã®ç©åã®äžã§æ¬¡ã®ããã«èšå®ããŸãã
ãããä»£å ¥ãããšäžèšã®åŒãåŸãŸãã
å§ãã®é ã¯å¹³åé»åã®å¯Ÿæ°ã§ãïŒ2é ç®ã¯è² ã®ãªã€ã©ãŒã»ãã¹ã±ããŒãå®æ°ã§ãïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Weissteinãåç §ïŒããªã€ã©ãŒã»ãã¹ã±ããŒãå®æ°ã¯7,000,000 ããžãããŸã§èšç®ãããŠããŠÎ¥ã§è¡šãããŸããÎ¥ ã¯çŽ 0.5772ã«çããã®ã§ãæåŸã®é ã¯â2.5067ã«ãªããŸãã
ææ°ã®ã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã¯å¿ èŠãªè£æ£ä¿æ°ãäžãããã€ãºæž¬å®ãç¹åŸŽãšããŠããŸãã
æ£ç¢ºãªçµæãåŸãããããã«ïŒå¿ èŠã«å¿ããŠå ããå¿ èŠã®ããïŒæ¢ç¥ã®è£æ£ä¿æ°ã«äžãããšå ±ã«ãã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã¯æ£ããèšå®ãããªããã°ãªããŸãããå ¥åä¿¡å·ãå°ããå Žåã¯ããªãã¡ã¬ã³ã¹ã»ã¬ãã«ãäœãããäºã«ããæ£ç¢ºã«æž¬å®ã§ããŸããããããªãã¡ã¬ã³ã¹ã»ã¬ãã«ãäœããããšå ¥åIF段ã®ã²ã€ã³ãå¢å€§ããŸããæåã®IF段ãéè² è·ã«ãªããªãããã«æ³šæããå¿ èŠã§ããIFå ¥ååè·¯ãéè² è·ã«ãªããšæªã¿ç©ãçããå¯èœæ§ããããŸããïŒãªãã¡ã¬ã³ã¹ã»ã»ã¯ã·ã§ã³ã®Fundamentals of Spectrum Analysis by Rauscherãåç §ïŒããã«ãå解èœåž¯åïŒRBWïŒãšãããªåž¯åïŒVBW)ãããããé«ããäºã«ããããã埮现ãªåšæ³¢æ°ãšæ¯å¹ ã®å解èœæž¬å®ãè¡ããŸãããããå解èœãé«ãããšæåŒæéãé·ããªããŸãã幞ãã«ããåžæã®æž¬å®å€ãåããé©åãªè£æ£ä¿æ°ãäžãããœãããŠãšã¢ãäŸçµŠå¯èœã§ãã
å®éšçµæ
å³ 16.ãªã·ãã¹ã³ãŒãã®æ¥ç¶
å³ 17.ã¹ãã¯ãã«ã»ã¢ãã©ã€ã¶ã®æ¥ç¶
Rohde & Schwarz SML-01 ã§çºçããå€èª¿ä¿¡å·ãTektronix CSA8000B and a Rohde & Schwarz FSIQ7ã䜿çšããŠæž¬å®ããŸãããäžã€ç®ã®SML-01ãšåãåšæ³¢æ°ã«èšå®ããã2ã€ç®ã®ç¡å€èª¿ã®SML-01ã¯CSA8000Bãããªã¬ãŒããã®ã«äœ¿çšããŸãã倧ããªã·ã³ã°ã«ã»ããŒã³å€èª¿ã«ããäœçžãã€ãºã倧ããªã¬ãŠã¹ã»ãã€ãºå€èª¿ãå°ããªãã€ãºå€èª¿ã解æããŸãããããã®å Žåã䜿çšãããä¿¡å·çºçåšã¯Rohde & Schwarz SML-01ã§ãã
代ããã®ãªã·ãã¹ã³ãŒãæ¥ç¶ã¯ãããªã¬ãŒãšãµã³ããªã³ã°å ¥åã®äž¡æ¹ã«å°å ããããã«ãåºåž¯åæµææ§ã¹ããªãã¿ã䜿çšããäºã§ãããã®æ¹æ³ã¯ïŒäººçºçã«äœãã€ãºæž¬å®çµæãçããå¯èœæ§ã®ããïŒäœåšæ³¢æ°ãã€ãºãé€å»ããŸãã
ä¿¡å·1
å³ 18.SML-01ã®10MHzåºåä¿¡å·ã101 kHzã§200mradå€èª¿
å³ 19.ç«ã¡äžãããšããžã®æ¡å€§å³
ç«ã¡äžãããšããžæé¢ã§ã®æ°Žå¹³ãã¹ãã°ã©ã ããšãã2.218 ns以å ã®æšæºå差㚠6.6 nsã®ããŒã¯toããŒã¯åå·®ã衚瀺ããŸãã
å³ 20.åäžåšæ³¢æ°ã®äœçžå€èª¿ãããåšæ³¢æ°
ã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã¯æããã«åäžåšæ³¢æ°ã®äœçžå€èª¿ã«ããã¹ãã¯ãã«ã瀺ããŠããŸãããã£ãªã¢åšæ³¢æ°ã®å³ã«ããæåã®é ã¯ããã»ã«ä¿æ° J1(Ξd)ã§ããJ1(Ξd) â Ξd/2ãªã®ã§ãå€èª¿ã¯200 mradãšè¿äŒŒããäºãã§ããŸãã
ä¿¡å·2
å³ 21.67 mrad RMSã®ã¬ãŠã¹ã»ãã€ãºã§å€èª¿ããã 10MHzã®SMLïŒ01åºåä¿¡å·
å³ 22.ç«ã¡äžãããšããžã®æ¡å€§å³
ç«ã¡äžãããšããžæé¢ã§ã®æ°Žå¹³ãã¹ãã°ã©ã ã¯ã1.005 ns以å ã®æšæºå差㚠7.92 nsã®ããŒã¯toããŒã¯åå·®ã衚瀺ããŸãããªã·ãã¹ã³ãŒãã®ããªã¬ãŒå ¥å粟床ã¯ã¹ã«ãŒã¬ãŒããäœããªããšäœäžããŸãã
å³23ã¯ãã£ãªã¢ãã1 MHzãŸã§ã®åºåž¯åãã€ãºã«å¯Ÿããã¹ãã¯ãã©ã ã瀺ããŸããã·ã³ã°ã«ã»ãµã€ããã³ãäœçžãã€ãºæž¬å®ã䜿ãïŒåŒ19åç §ïŒãèšç®ãããäœçžãã€ãºã¯0.0676 ã©ãžã¢ã³ã®rmsæ¯å¹ ã«ãªããããã¯çŽ1.075 nsã®æéãžãã¿ã«çžåœããŸãã
å³ 23.ãã£ãªã¢ãã1 MHz ãŸã§ã®ãã€ãºãå«ã10 MHzä¿¡å·
ä¿¡å·3
å³ 24.ã¯ãªãŒã³ãª 1 GHzãçæããããã«èšå®ãããSML-01
å³ 25.ç«ã¡äžãããšããžã®æ¡å€§å³
ãã®å Žåãåå·®ã¯éåžžã«å°ãããªã·ãã¹ã³ãŒãã®ããªã¬ã»ãžãã¿ä»¥äžã§ããçµæã¯æšæºåå·®837.3 fs ã§ããŒã¯toããŒã¯åå·®5.56 psã瀺ããŠããŸãã
å³ 26.äœçžãã€ãº1.6 mrad RMSãå«ããã«ã¹ã±ãŒã«1 GHzä¿¡å·
ã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã¯äžå¿ã1 GHzã§ãã¹ãã³ã2 MHz.ã«èšå®ãããŠããŸããåšæ³¢æ°ç¯å²ãå€ããäºã«ãããã€ãããã¯ã»ã¬ã³ãžã¯åºãããäºã¯ã§ããŸããã倧ããªãã£ãªã¢ä¿¡å·ã¯ã¹ãã³ããå€ããŸãã
å³ 27.1.6mrad RMSäœçžãã€ãºãå«ãã·ã³ã°ã«ã»ãµã€ããã³ã1GHz ä¿¡å·
ãã£ãªã¢ä¿¡å·ãã5KHzã®ç¹ããå§ãŸãç¯å²ã§å³27ã¯åºåž¯åäœçžãã€ãºããã£ãªã¢ãã1 MHzãŸã§ããäºã瀺ããŠããŸããã¬ãã¡ã©ã³ã¹ã»ã¬ãã«ãäœéãããšãå³27.å³27 ã«çŸããŠããæªã¿ãçããŸããæ£ç¢ºãªçµæãåŸãã«ã¯ã枬å®ãããçãééã§è¡ãå¿ èŠããããŸãããã£ãªã¢ã®10 kHz以å ã§ã®æž¬å®ã¯å ¥åIF段ãéè² è·ã«ãªããªããªãã¡ã¬ã³ã¹ã»ã¬ãã«ã§ãªããã°ãªããŸããã
ã·ã³ã°ã«ã»ãµã€ããã³ãã®æž¬å®ã䜿ããšïŒåŒ19åç §ïŒãäœçžãã€ãºã¯1.6 mradãšæž¬å®ãããŸãããã㯠255 fsã«çžåœãããªã·ãã¹ã³ãŒãã®ããªã¬ã»ãžãã¿å解èœããã¯ããã«å°ããã§ãã
å³ 28.1.6 mrad RMS äœçžãã€ãºãå«ã¿ééè² è·å ¥å段ã®ã·ã³ã°ã«ã»ãµã€ããã³ã1 GHzä¿¡å·
é«éã³ã³ããŒã¿
äœçžãã€ãºãšãžãã¿ãAD9235åè·¯ã«å°å ¥ããŸãããåŸãããçµæãã¹ãã¯ãã©ã ã»ã¢ãã©ã€ã¶ã§ç¢ºèªããå°ãåºããçè«ãšçžé¢ããšããŸãããAD9235ã¯ãµã³ãã«ã»ã¯ããã¯65Mã§SNRçŽ70 dBcãç¹åŸŽãšããé«éA/Dã³ã³ããŒã¿ã§ããå®éšã¯CTS5340ãã¹ã¿ãŒã§è¡ãããŸãããå ¥åããŒã³ãšã¯ããã¯ã®äž¡æ¹ãšãRohde & Schwarz SMGUã§çæããŸãããå ¥ååšæ³¢æ°ã¯2.4 MHz ã«èšå®ããŸãããåã¯ããã¯å ¥åã 259.995 MHzã«èšå®ããååšããŠãµã³ããªã³ã°ã»ã¬ãŒã fs â 65 MSPSãçæããŸãããæå¹ãªãµã³ããªã³ã°ã»ã¬ãŒãfes â fs/15ãçæããããããµã³ããªã³ã°ã»ã¬ãŒãããã·ã¡ãŒã·ã§ã³ããŸããã
åè·¯ã¯éåžž70 dBcçšåºŠã®SNRã«ãªããŸãããã³1827ã«æãè¿ãããåºæ¬æ³¢ãå«ã4kFFTã䜿çšããæšæºçãªé»åã¹ãã¯ãã«å¯åºŠãå³29ã«ç€ºããŸãã
å³ 29.AD9235 ADCåè·¯ã®FFTããµã³ãã«ã»ã¬ãŒããçŽ65MSPS/15ã«ãã·ã¡ãŒã·ã§ã³ããå ¥ååšæ³¢æ°ã2.4 MHzã«èšå®
ä¿¡å·ÎŠ(t) = 0.01 sin2Ï10,000tã§åºæ¬æ³¢ãå€èª¿ããŸãããåŸãããçµæã®é»åã¹ãã¯ãã«å¯åºŠãå³30ã«ç€ºããŸãã
å³ 30.åºæ¬æ³¢ã10 kHz ããŒã³ã§å€èª¿ããAD9235 ADCåè·¯ã®FFT
å³30ã¯åºæ¬æ³¢åšèŸºã§å€èª¿ãæå³ãã察称ã®ããŒã¯ã瀺ããŸããFFT ã®ãã³å¹ ã¯çŽ 1057 Hz ã§ãããã³ãæ°ãããšãäž»ãªããŒã¯ã¯åºæ¬æ³¢ãã9çªç®ãš10çªç®ã®ãã³ã«èŠã€ãããŸãããããã¯9.5 kHz ãš 10.5 kHzã®éã®å€èª¿ãæå³ããŸããå€èª¿é ã¯10 kHzã®çŽæ¥ã®åæ°ãéãŠã€ã³ãã®FFTã§ã¯ãªããµã³ããªã³ã°ã»ã¬ãŒãã«ããæ¡æ£ãããŸããå°ããä¿¡å·ã®å€èª¿ïŒå€èª¿ããŒã¯ã 50 dBc以äžããã®ã§å®å šãªä»®å®ã§ãïŒã®å Žåãæåã®å€èª¿ããã»ã«é J1(Ξd) ã¯çŽÎžd/2ã§ããå€èª¿é åšèŸºã®8ã€ã®ãã£ãšãé«ãããŒã¯ã®é»åãåèšããŠäžèšã®å€ãåŸãŸãã
PJ1 â 2.0324 Ã 10â5
Ξd/2 = âPJ1â 0.0045
Ξd = 0.009
ããšãå€èª¿é ãã¹ãã¯ãã«å šäœã«åºãã£ãŠããŠããã»ãšãã©ã®å€èª¿ãšãã«ã®-ã¯fc ± fmåšèŸºäžå¿ã«ãªããŸãã8ã€ã®é ãåèšããã°å®éã®å€ã®10%以å ã®è¿äŒŒå€ã«ãªããŸãã
äœçžãã€ãºãå ããåºæ¬æ³¢ã®é»åã¹ãã¯ãã«å¯åºŠãå³31ã«ç€ºããŸãã
å³ 31.åºæ¬æ³¢ãå€èª¿ããäœçžãã€ãºã®ããAD9235 ADC åè·¯ã®FFT
CTS5340ãã¹ã¿ãŒã¯ãã£ã«ã¿åŠçããä¿¡å·ãåè·¯åºæ¿ã«éããŸãã2.4 MHzãã£ã«ã¿ã®ç䟡ãã€ãºåž¯åå¹ ã¯çŽ300kHzã§ãã垯åå¶éããããã€ãºãåºæ¬æ³¢åšèŸºã«ã¯ã£ãããšèŠãããŸãããããã¯2.4 MHzå ¥åããŒã³äžã®äœçžå€èª¿ããããã€ãºã§ããäœçžãã€ãºã«ããSNRã¯58 dBcãšãªããŸãã
å³ 32.äœçžãã€ãº1.5 mradãå«ãåºæ¬æ³¢ã®ã·ã³ã°ã«ã»ãµã€ããã³ãã»ãã€ãºã»ã¹ãã¯ãã«
å ¥åä¿¡å·ã®ã·ã³ã°ã«ã»ãµã€ããã³ã枬å®ã¯äœçžãã€ãº1.5 mradã瀺ããŸãã
Prms = A2
Prms = 2.25 Ã 10â6 = â56.478 dB
åŸã£ãŠä¿¡å·æºäœçžãã€ãºã¯åè·¯ã®ãã¹ãçµæã«äžèŽããŸãã
ãµã³ããªã³ã°ã»ã¯ããã¯ã«å ãããããžãã¿ã®çµæãå³33ã«ç€ºããŸãã
å³ 33.ãžãã¿ã»ã¯ããã¯ã§ãµã³ããªã³ã°ããAD9235ADCåè·¯ã®FFT
ãã®å Žåé»åã¹ãã¯ãã«å¯åºŠã®ãã€ãºã»ããã¢ã¯å°ãäžæãSNRã64 dBcã«ãªããŸãããã¯ããã¯æºã¯259.995MHzã«èšå®ããã Rohde & Schwarz SML-01 ã§ããSML-01ã¯ããã¯æºã®ã·ã³ã°ã«ã»ãµã€ããã³ã枬å®ãå³34ã«ç€ºããŸãã
å³ 34.äœçžãã€ãº
ã¯ããã¯æºã¯66.9 mrad ã®äœçžãã€ãºããããŸãã
Atrms = 0.0669/(2Ï259.995 Ã 106)
â 40.953 ps
ãµã³ããªã³ã°ã»ã¯ããã¯ã®äœçžãã€ãºã¯çŽ41 psã®ã¯ããã¯æéãžãã¿ã«çžåœããŸãããžãã¿ã¯2.4 MHzå ¥åä¿¡å·äžã®äœçžãã€ãºïŒã©ãžã¢ã³ïŒã«é¢é£ãããäºãã§ããŸãã
Atrms = (40.953 Ã 10â12) Ã (2Ï2.4 Ã 106)
â 0.618 mrad
41 psã®ã¯ããã¯ã»ãžãã¿ã¯2.4 MHzåºæ¬æ³¢äžã®äœçžãã€ãº0.618 mradã«çžåœããŸãã
Prms = A2rms
Prms = 3.814 Ã 10â7 = â64.187 dB
ãµã³ããªã³ã°ã»ã¯ããã¯äžã®ãã€ãºã¯åè·¯ã®ãã¹ãçµæã«äžèŽããŸãã
çµè«
ãã®ã¢ããªã±ãŒã·ã§ã³ã»ããŒãã«ç€ºããçè«ã«ããäœçžãã€ãºãšãžãã¿éã®çŽæ¥çãªé¢ä¿ãšãããã®åšæ³¢æ°é åã®è¡šç€ºãåŸãããŸããåšæ³¢æ°é åã§äœçžãã€ãºãšãžãã¿ã®è§£æãè¡ããšãã€ãºä¿¡å·ã®æåã匷調ãããŸããããã«ãåšæ³¢æ°é åã§ã®æž¬å®ã«ãããããé«ãåšæ³¢æ°ã§é«ãå解èœãåŸãããŸãã
åèè³æ
Hewlett Packard.1998.Application Note 1303.Spectrum Analyzer Measurements and Noise.
Manassewitsch, Vadim.1987.Frequency Synthesizers Theory and Design Third Edition.Wiley-Interscience.
Norsworthy, Steven, Richard Schreier and Gabor Temes.1997.Delta-Sigma Data Converters Theory Design and Simulation.IEEE Press
Oppenheim, Alan and Ronald W. Schafer.1989.Discrete-Time Signal Processing.Prentice Hall.
Papoulis, Athanasios.1984.Probability, Random Variables,and Stochastic Processes.McGraw-Hill.
Rauscher, Christoph.2001.Fundamentals of Spectrum Analysis.Germany:Rohde & Schwarz.
Tektronix.2009.XYZs of Oscilloscopes.Application Note.
Tektronix.2001.Analyzing Clock Jitter Using Excel.Application Note.
Tektronix.2004.Understanding and Performing Precise Jitter Analysis.Application Note.
Tektronix.2000.Automatic Measurement Algorithms and Methods for the 8000 Series Sampling Oscilloscopes.Application Note.
van de Plassche, Rudy.1994.Integrated Analog-To-Digital and Digital-To-Analog Converters.The Netherlands:Kluwer Academic Publishers.
Weisstein, Eric.1999.Concise Encyclopedia of Mathematics.Florida:CRC Press.