Version 4
SHEET 1 1456 804
WIRE 752 304 720 304
WIRE 416 320 352 320
WIRE 448 320 416 320
WIRE 576 320 528 320
WIRE 624 320 576 320
WIRE 656 320 624 320
WIRE 576 336 576 320
WIRE 752 336 720 336
WIRE 656 384 656 352
WIRE 352 432 352 400
WIRE 576 432 576 400
WIRE 368 608 352 608
WIRE 560 608 544 608
WIRE 352 624 352 608
WIRE 544 624 544 608
WIRE 352 720 352 704
WIRE 544 720 544 704
FLAG 352 432 0
FLAG 656 384 0
FLAG 752 304 out1
FLAG 752 336 \out1
FLAG 416 320 B1.out
FLAG 352 720 0
FLAG 544 720 0
FLAG 368 608 sine1
FLAG 560 608 ramp1
FLAG 576 432 0
FLAG 624 320 C
SYMBOL Digital\\schmitt 656 256 R0
WINDOW 3 -57 -20 Left 2
WINDOW 123 -57 -4 Left 2
SYMATTR Value Vt=2.5 Vh=1 Vlow=0 Vhigh=15
SYMATTR Value2 tripdt={trdt}
SYMATTR InstName A3
SYMBOL bv 352 304 R0
WINDOW 0 -28 13 Left 2
WINDOW 3 11 104 Left 2
WINDOW 123 11 120 Left 2
SYMATTR InstName B1
SYMATTR Value V=if((V(sine1)>V(ramp1)),5,0)
SYMATTR Value2 tripdv=1 tripdt={trdt}
SYMBOL voltage 352 608 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName Sine1
SYMATTR Value SINE(2.5 2.5 50 0 0 90)
SYMBOL voltage 544 608 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName Ramp1
SYMATTR Value PULSE(0 5 0 67.5u 67.5u 0 135u)
SYMBOL res 544 304 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 2.802
SYMBOL cap 560 336 R0
SYMATTR InstName C1
SYMATTR Value 100n
TEXT 344 176 Left 2 !.tran 20m
TEXT 592 168 Left 2 ;The Schmitt trigger trip points\nlow trip point is Vt-Vh =1.5\nhigh trip point is Vt+Vh. =3.5
TEXT 352 520 Left 2 !.meas tlh find v(c) when v(out1)=7.5 rise=1 td=9.584m\n.meas thl find v(c) when v(out1)=7.5 fall=1 td=9.584m
TEXT 352 480 Left 2 !.param trdt=1m
TEXT 352 496 Left 2 !.step param trdt list 1m 10n 1n
TEXT 344 192 Left 2 !.opt plotwinsize=0
TEXT 368 448 Left 2 ;tripdv=1 tripdt={trdt}