Version 4
SHEET 1 1568 680
WIRE 1120 -32 928 -32
WIRE 928 16 928 -32
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 1168 96 1040 96
WIRE 1296 96 1232 96
WIRE 112 112 112 96
WIRE 160 112 160 96
WIRE 416 112 416 96
WIRE 464 112 464 96
WIRE 928 144 928 96
WIRE 96 160 32 160
WIRE 208 160 176 160
WIRE 400 160 352 160
WIRE 512 160 480 160
WIRE 1040 176 1040 96
WIRE 1168 176 1040 176
WIRE 1296 176 1296 96
WIRE 1296 176 1248 176
WIRE 1120 240 1120 -32
WIRE -208 256 -240 256
WIRE -128 256 -208 256
WIRE 32 256 32 160
WIRE 32 256 -48 256
WIRE 352 256 352 160
WIRE 352 256 32 256
WIRE 512 256 512 160
WIRE 816 256 512 256
WIRE 1040 256 1040 176
WIRE 1040 256 896 256
WIRE 1088 256 1040 256
WIRE 1296 272 1296 176
WIRE 1296 272 1152 272
WIRE 1088 288 1040 288
WIRE -208 304 -208 256
WIRE 208 304 208 160
WIRE 256 304 208 304
WIRE 288 304 256 304
WIRE 512 304 512 256
WIRE 560 304 512 304
WIRE 592 304 560 304
WIRE 1040 320 1040 288
WIRE 1040 320 992 320
WIRE 1296 320 1296 272
WIRE 256 336 256 304
WIRE 304 336 256 336
WIRE 432 336 304 336
WIRE 560 336 560 304
WIRE 624 336 560 336
WIRE 912 336 912 320
WIRE 912 336 720 336
WIRE 512 352 512 304
WIRE 208 368 208 304
WIRE 304 400 304 336
WIRE 624 416 624 336
WIRE 1120 432 1120 304
WIRE 1296 432 1296 400
WIRE 1408 432 1296 432
WIRE -208 448 -208 384
WIRE 208 448 208 432
WIRE 512 448 512 416
WIRE 304 528 304 480
WIRE 304 528 192 528
WIRE 624 528 624 496
WIRE 624 528 544 528
WIRE 1296 528 1296 496
WIRE 304 608 304 592
WIRE 624 608 624 592
WIRE 432 656 432 336
WIRE 720 656 720 336
WIRE 720 656 432 656
FLAG 224 48 0
FLAG -208 448 0
FLAG 288 304 A1
IOPIN 288 304 Out
FLAG 528 48 0
FLAG 592 304 A2
IOPIN 592 304 Out
FLAG 1120 432 0
FLAG 928 144 0
FLAG -240 256 Inp
IOPIN -240 256 In
FLAG 1296 528 0
FLAG 624 608 0
FLAG 304 608 0
FLAG 208 448 0
FLAG 512 448 0
FLAG 544 528 B2
IOPIN 544 528 Out
FLAG 192 528 B1
IOPIN 192 528 Out
FLAG 1408 432 Out1
IOPIN 1408 432 Out
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 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PULSE(-1 1 0 1p 1p {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 2
WINDOW 39 24 124 Left 2
SYMATTR InstName V2
SYMATTR Value SINE(1.8V 5m 50.1k)
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 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V3
SYMATTR Value PULSE(-1 1 {2*t} 1p 1p {t} {4*t})
SYMBOL cap 496 352 R0
SYMATTR InstName C2
SYMATTR Value {cap}
SYMBOL Opamps\\LT6231 1120 272 R0
SYMATTR InstName U1
SYMBOL res 912 240 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R4
SYMATTR Value 10000
SYMBOL res 1008 304 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R5
SYMATTR Value 10000
SYMBOL res 1264 160 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R6
SYMATTR Value 1000k
SYMBOL cap 1232 80 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C3
SYMATTR Value {cap2}
SYMBOL voltage 928 0 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V4
SYMATTR Value 3.3V
SYMBOL res 1280 304 R0
WINDOW 3 33 76 Left 2
SYMATTR Value 100k
SYMATTR InstName R7
SYMBOL cap 1280 432 R0
SYMATTR InstName C6
SYMATTR Value 10n
SYMBOL res 608 400 R0
SYMATTR InstName R8
SYMATTR Value 100k
SYMBOL cap 608 528 R0
SYMATTR InstName C7
SYMATTR Value 10n
SYMBOL res 288 384 R0
SYMATTR InstName R10
SYMATTR Value 100k
SYMBOL cap 288 528 R0
SYMATTR InstName C8
SYMATTR Value 10n
TEXT -624 -48 Left 2 !.model MYSW SW(Ron 5; Roff 1Meg; vt=0; Vh=0 )
TEXT -792 -80 Left 2 !.tran 0 30m 10m
TEXT -488 24 Left 2 ;QSD  3.2019
TEXT -896 176 Left 2 !.param t=1/clock
TEXT -888 128 Left 2 !.param clock=200k
TEXT -896 16 Left 2 !.param cap=33n
TEXT -560 88 Left 2 ;FFT :\nBlackman-Harris four-term window
TEXT -896 48 Left 2 !.param cap2=3p