Version 4
SHEET 1 960 680
WIRE 544 128 464 128
WIRE 704 128 544 128
WIRE 864 128 768 128
WIRE -64 144 -176 144
WIRE 96 144 -64 144
WIRE 288 144 240 144
WIRE 400 144 288 144
WIRE -176 160 -176 144
WIRE 704 160 576 160
WIRE 288 208 240 208
WIRE 336 208 288 208
WIRE 576 208 576 160
WIRE -176 256 -176 240
WIRE 576 304 576 288
FLAG 544 128 r1
FLAG 576 304 0
FLAG -176 256 0
FLAG 864 128 out
IOPIN 864 128 Out
FLAG 288 144 sine
FLAG 288 208 cos
FLAG -64 144 mod
SYMBOL SpecialFunctions\\modulate2 96 144 R0
WINDOW 39 -27 123 Left 2
SYMATTR SpiceLine mark=1000 space=0
SYMATTR InstName A1
SYMBOL Digital\\schmitt 400 80 R0
WINDOW 39 -36 126 Left 2
WINDOW 123 -36 154 Left 2
SYMATTR SpiceLine Vt=0 Vh=1m
SYMATTR Value2 tripdt=1u
SYMATTR InstName A2
SYMBOL Digital\\and 736 80 R0
WINDOW 123 -59 115 Left 2
SYMATTR Value2 tripdt=1u
SYMATTR InstName A3
SYMBOL bv 576 192 R0
SYMATTR InstName B1
SYMATTR Value V=-delay(V(r1),1m)+1
SYMBOL voltage -176 144 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value PWL(0 0.02 1 0.4)
TEXT -168 -32 Left 2 !.tran 0 1 0 10u
TEXT -168 0 Left 2 !.options plotwinsize=0
TEXT -160 304 Left 2 ;20Hz -> 400Hz
TEXT 208 -40 Left 2 ;Frequency Sweep With Constant Pulse Width