Version 4 SHEET 1 2036 1860 WIRE -32 -112 -80 -112 WIRE 80 -112 32 -112 WIRE -752 -48 -1072 -48 WIRE -464 -48 -672 -48 WIRE -336 -48 -464 -48 WIRE -80 -48 -80 -112 WIRE -80 -48 -336 -48 WIRE 80 -48 80 -112 WIRE 128 -48 80 -48 WIRE 304 -48 208 -48 WIRE 528 -48 304 -48 WIRE 976 -48 624 -48 WIRE 1136 -48 976 -48 WIRE 1280 -48 1136 -48 WIRE 1408 -48 1280 -48 WIRE -464 -16 -464 -48 WIRE 1280 -16 1280 -48 WIRE 1408 -16 1408 -48 WIRE -1072 0 -1072 -48 WIRE 976 0 976 -48 WIRE -80 16 -80 -48 WIRE -32 16 -80 16 WIRE 80 16 80 -48 WIRE 80 16 48 16 WIRE 528 16 528 -16 WIRE 528 16 432 16 WIRE 624 16 624 -16 WIRE 720 16 624 16 WIRE -464 96 -464 64 WIRE 432 96 432 16 WIRE 720 96 720 16 WIRE 976 96 976 64 WIRE 1280 96 1280 64 WIRE 1408 96 1408 48 WIRE -1072 128 -1072 80 WIRE 832 496 800 496 WIRE 944 496 912 496 WIRE -32 512 -80 512 WIRE 80 512 32 512 WIRE -784 576 -1072 576 WIRE -464 576 -704 576 WIRE -320 576 -464 576 WIRE -80 576 -80 512 WIRE -80 576 -320 576 WIRE 80 576 80 512 WIRE 208 576 80 576 WIRE 448 576 208 576 WIRE 800 576 800 496 WIRE 800 576 544 576 WIRE 1136 576 800 576 WIRE 1264 576 1136 576 WIRE 1392 576 1264 576 WIRE -464 608 -464 576 WIRE 944 608 944 496 WIRE 1264 608 1264 576 WIRE 1392 608 1392 576 WIRE -1072 624 -1072 576 WIRE -80 640 -80 576 WIRE -32 640 -80 640 WIRE 80 640 80 576 WIRE 80 640 48 640 WIRE 448 640 448 608 WIRE 448 640 352 640 WIRE 544 640 544 608 WIRE 640 640 544 640 WIRE -464 720 -464 688 WIRE 352 720 352 640 WIRE 640 720 640 640 WIRE 944 720 944 672 WIRE 1264 720 1264 688 WIRE 1392 720 1392 672 WIRE -1072 752 -1072 704 FLAG 432 96 0 FLAG 720 96 0 FLAG -1072 128 0 FLAG 976 96 0 FLAG 1280 96 0 FLAG 1408 96 0 FLAG 1136 -48 out_a FLAG -336 -48 in_a FLAG 304 -48 int_a FLAG -464 96 0 FLAG -1072 752 0 FLAG 944 720 0 FLAG 1264 720 0 FLAG 1392 720 0 FLAG 1136 576 out_c FLAG -320 576 in_c FLAG 208 576 int_c FLAG -464 720 0 FLAG 352 720 0 FLAG 640 720 0 SYMBOL voltage -1072 -16 R0 WINDOW 3 24 160 Left 2 WINDOW 123 24 132 Left 2 WINDOW 39 0 0 Left 2 SYMATTR Value PULSE(0 20 100n 1n 1n 499u 1000u) SYMATTR Value2 AC 20 SYMATTR InstName V1 SYMBOL res -48 32 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName Rtip_a SYMATTR Value 9MEG SYMBOL res 1264 -32 R0 SYMATTR InstName Ri_a SYMATTR Value 1MEG SYMBOL tline 576 -32 R0 WINDOW 3 4 -36 Left 2 SYMATTR Value Td=10n Z0=50 SYMATTR InstName T1 SYMBOL cap 960 0 R0 SYMATTR InstName Cadj_a SYMATTR Value 30p SYMBOL cap -32 -96 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName Ctip_a SYMATTR Value 28p SYMBOL res -768 -32 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName Rg_a SYMATTR Value 50 SYMBOL cap 1392 -16 R0 SYMATTR InstName Ci_a SYMATTR Value 20p SYMBOL res -480 -32 R0 SYMATTR InstName Rt_a SYMATTR Value 50 SYMBOL voltage -1072 608 R0 WINDOW 3 24 160 Left 2 WINDOW 123 24 132 Left 2 WINDOW 39 0 0 Left 2 SYMATTR Value PULSE(0 20 100n 1n 1n 499u 1000u) SYMATTR Value2 AC 20 SYMATTR InstName V3 SYMBOL res -48 656 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName Rtip_c SYMATTR Value 9MEG SYMBOL res 1248 592 R0 SYMATTR InstName Ri_c SYMATTR Value 1MEG SYMBOL cap 928 608 R0 SYMATTR InstName Cadj_c SYMATTR Value 30p SYMBOL cap -32 528 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName Ctip_c SYMATTR Value 17p SYMBOL res -800 592 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName Rg_c SYMATTR Value 50 SYMBOL cap 1376 608 R0 SYMATTR InstName Ci_c SYMATTR Value 20p SYMBOL res 816 512 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName Rser_c SYMATTR Value {RSERC} SYMBOL ltline 496 592 R0 SYMATTR InstName O2 SYMATTR Value LTRA2 SYMBOL res -480 592 R0 SYMATTR InstName Rt_c SYMATTR Value 50 SYMBOL res 112 -32 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R1_a SYMATTR Value 50 TEXT -1080 -672 Left 2 ;.ac dec 500 0.1k 200MEG TEXT -1072 -712 Left 2 !.tran 0 1u 0 1n TEXT 8 -288 Left 2 ;PROBE-A, 10:1, WITH LOSSLESS TRANSMISSION LINE Z=50 Ohm TEXT 160 464 Left 2 !.MODEL LTRA2 LTRA(R=190 C=50p L=500n LEN=2) TEXT 0 336 Left 2 ;PROBE-C, 10:1, WITH LOSSY TRANSMISSION LINE Z=100 Ohm, R=190 Ohm/m TEXT -240 -784 Left 2 ;10:1 HIGH IMPEDANCE OSCILLOSCOPE PROBE NEEDS LOSSY CABLE TEXT -232 -496 Left 2 ;Probe-a(selfmade): probe with 50 Ohm cable, l=2m, R'=0 (lossless, standard coax) TEXT -232 -456 Left 2 ;Probe-c(HP/Ag, Tek): their probes have typ. 100 Ohm cable, l=2m, R'=190 Ohm/m, special cable TEXT -232 -416 Left 2 ;R' is the ohmic resistance per 1m length of the inner conductor. TEXT -1080 -632 Left 2 ;.AC analysis can be used also to see the "flat" frequency response. TEXT -232 -592 Left 2 ;Characteristic Impedance Z: Z=sqrt(L/C) TEXT 1224 -240 Left 2 ;OSCILLOSCOPE TEXT 584 -216 Left 2 ;length = 2m TEXT -1048 -216 Left 2 ;PULSE GENERATOR\n \nf=1MHz, Trise=1ns, Tfall=1ns TEXT -520 -216 Left 2 ;FEEDTROUGH\n50 Ohm TEXT -528 416 Left 2 ;FEEDTROUGH\n50 Ohm TEXT 1224 384 Left 2 ;OSCILLOSCOPE TEXT 160 424 Left 2 ;Inner conductor with ohmic resistance of 190 Ohm/m TEXT 296 -216 Left 2 ;Standard 50 Ohm cable TEXT 296 -184 Left 2 ;Resistance of inner conductor omitted TEXT -1048 408 Left 2 ;PULSE GENERATOR\n \nf=1MHz, Trise=1ns, Tfall=1ns TEXT -232 -704 Left 2 ;Probe cables need a high resistance of the inner conductor. TEXT -232 -560 Left 2 ;Delay: Tpd/m = sqrt(L*C) = 5ns/m or v=1/sqrt(L*C) = 2/3*c0 choosen TEXT 616 -784 Left 2 ;Helmut Sennewald, 4/25/2004 TEXT -232 -672 Left 2 ;Typical values are 100 Ohm/m to 200 Ohm/m depending on the cable's Z-impedance. TEXT -232 -640 Left 2 ;Z from dimensions: Z = 60/sqrt(Er)*log(D/d) [Ohm] , D/d = outer/inner diameter TEXT -256 280 Left 2 ;HP/Ag or Tek 10:1 PROBE, LENGTH 2M TEXT -1080 -456 Left 2 ;http://www.tek.com/site/ps/0,,60-15265-INTRO_EN,00.html TEXT -1080 -424 Left 2 ;http://www.probemaster.com/helpful.htm TEXT -1080 -488 Left 2 ;Some links: TEXT -1080 -776 Left 2 ;Plot V(out_a) and V(out_c) TEXT -824 -712 Left 2 !.step param RSERC list 1 500 LINE Normal 736 -112 400 -112 2 LINE Normal 752 -112 736 -112 2 LINE Normal 752 -112 752 -112 2 LINE Normal 752 16 400 16 2 LINE Normal -32 -176 240 -176 2 LINE Normal -288 -48 -32 -176 2 LINE Normal -32 80 -288 -48 2 LINE Normal 240 80 -32 80 2 LINE Normal 240 80 240 80 2 LINE Normal 1504 -112 1488 -112 LINE Normal 1520 -208 1504 -112 LINE Normal 1536 -160 1520 -208 LINE Normal 1552 -176 1536 -160 LINE Normal 1568 -160 1552 -176 LINE Normal 1600 -160 1568 -160 LINE Normal 1600 -80 1600 -160 LINE Normal 1616 -112 1600 -80 LINE Normal 1648 -112 1616 -112 LINE Normal 656 512 320 512 2 LINE Normal 672 512 656 512 2 LINE Normal 672 512 672 512 2 LINE Normal 672 640 320 640 2 LINE Normal 1504 512 1488 512 LINE Normal 1520 416 1504 512 LINE Normal 1536 464 1520 416 LINE Normal 1552 448 1536 464 LINE Normal 1568 464 1552 448 LINE Normal 1600 464 1568 464 LINE Normal 1600 544 1600 464 LINE Normal 1616 512 1600 544 LINE Normal 1648 512 1616 512 LINE Normal 720 752 720 752 2 LINE Normal 240 -128 240 -176 2 LINE Normal 240 -112 240 -128 2 LINE Normal 240 80 240 16 2 LINE Normal 240 16 240 -112 2 LINE Normal -48 448 128 448 2 LINE Normal -256 576 -48 448 2 LINE Normal -48 704 -256 576 2 LINE Normal 128 704 -48 704 2 LINE Normal 128 704 128 704 2 LINE Normal 128 496 128 448 2 LINE Normal 128 512 128 496 2 LINE Normal 128 704 128 640 2 LINE Normal 128 640 128 512 2 LINE Normal 1008 48 944 0 LINE Normal 960 0 944 0 LINE Normal 944 16 944 0 LINE Normal 976 656 912 608 LINE Normal 928 608 912 608 LINE Normal 912 624 912 608 RECTANGLE Normal 1728 176 1184 -288 2 RECTANGLE Normal 1680 -64 1456 -240 RECTANGLE Normal -608 208 -1136 -256 2 RECTANGLE Normal -384 144 -528 -144 2 RECTANGLE Normal -608 816 -1136 352 2 RECTANGLE Normal -384 768 -528 480 2 RECTANGLE Normal 1728 800 1184 336 2 RECTANGLE Normal 1680 560 1456 384 RECTANGLE Normal 1072 176 -288 -256 1 RECTANGLE Normal 1072 800 -256 368 1 CIRCLE Normal 432 16 352 -112 2 CIRCLE Normal 352 640 272 512 2 ARC Normal 704 -112 800 16 758 -11 765 -128 2 ARC Normal 624 512 720 640 678 613 685 496 2