Version 4
SHEET 1 1564 680
WIRE 224 32 176 32
WIRE 528 32 480 32
WIRE 224 48 224 32
WIRE 528 48 528 32
WIRE 96 96 96 32
WIRE 112 96 96 96
WIRE 176 96 176 32
WIRE 176 96 160 96
WIRE 400 96 400 32
WIRE 416 96 400 96
WIRE 480 96 480 32
WIRE 480 96 464 96
WIRE 112 112 112 96
WIRE 160 112 160 96
WIRE 416 112 416 96
WIRE 464 112 464 96
WIRE 96 160 48 160
WIRE 208 160 176 160
WIRE 400 160 352 160
WIRE 512 160 480 160
WIRE 960 224 848 224
WIRE -208 256 -240 256
WIRE -128 256 -208 256
WIRE 48 256 48 160
WIRE 48 256 -48 256
WIRE 352 256 352 160
WIRE 352 256 48 256
WIRE -208 304 -208 256
WIRE 208 304 208 160
WIRE 288 304 208 304
WIRE 512 304 512 160
WIRE 592 304 512 304
WIRE 848 320 848 224
WIRE 512 352 512 304
WIRE 208 368 208 304
WIRE -208 448 -208 384
WIRE 208 448 208 432
WIRE 512 448 512 416
WIRE 848 448 848 400
FLAG 224 48 0
FLAG -208 448 0
FLAG 208 448 0
FLAG 288 304 A1
IOPIN 288 304 Out
FLAG 528 48 0
FLAG 512 448 0
FLAG 592 304 A2
IOPIN 592 304 Out
FLAG 960 224 Q
IOPIN 960 224 Out
FLAG -240 256 Inp
IOPIN -240 256 In
FLAG 848 448 0
SYMBOL sw 192 160 R90
SYMATTR InstName S1
SYMATTR Value MYSW
SYMBOL voltage 80 32 R270
WINDOW 0 -32 56 VBottom 2
WINDOW 3 104 57 VTop 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value PULSE(-1 1 0 10n 10n {t} {4*t})
SYMBOL res -32 240 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 50
SYMBOL voltage -208 288 R0
WINDOW 123 0 0 Left 0
WINDOW 39 24 124 Left 2
SYMATTR InstName V2
SYMATTR Value SINE(1.5V 10m 383.5k)
SYMBOL cap 192 368 R0
SYMATTR InstName C1
SYMATTR Value {cap}
SYMBOL sw 496 160 R90
SYMATTR InstName S2
SYMATTR Value MYSW
SYMBOL voltage 384 32 R270
WINDOW 0 -32 56 VBottom 2
WINDOW 3 59 66 VTop 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(-1 1 {2*t} 10n 10n {t} {4*t})
SYMBOL cap 496 352 R0
SYMATTR InstName C2
SYMATTR Value {cap}
SYMBOL bv 848 304 R0
SYMATTR InstName B1
SYMATTR Value V= ( V(A1)-V(A2) ) * 100
TEXT -624 -48 Left 2 !.model MYSW SW(Ron 5; Roff; 1Meg; vt=0; Vh=0 )
TEXT -792 -80 Left 2 !.tran 0 20m 18m
TEXT -488 24 Left 2 ;QSD  3.2019
TEXT -904 224 Left 2 !.param t=1/clock
TEXT -896 96 Left 2 !;.param clock=2868k   ; 693kHz
TEXT -904 136 Left 2 !.param clock=326k  ;57.5kHz
TEXT -896 16 Left 2 !.param cap=33n
TEXT -488 88 Left 2 ;FFT :\nBlackman-Harris four-term window
TEXT -896 48 Left 2 !.param cap2=330p
TEXT -896 184 Left 2 !;.param clock=888k   ;198kHz