* SPICE netlist
XU1 N010 N002 +15 -15 TRI LT1001 ;pnba In+)In-)V+)V-)OUT
J1 N002 N014 0 2N3819
Q1 N003 0 N013 0 2N3904
Q2 N005 N008 N013 0 2N3904
XU3 0 N005 +15 -15 N015 LT1001 ;pnba In+)In-)V+)V-)OUT
R10 N013 N015 2k
C3 N015 N005 100p
R12 +15 N005 1Meg
XU4 0 N007 +15 -15 N008 LT1001 ;pnba In+)In-)V+)V-)OUT
R9 N008 N007 1k
R13 N007 N012 55.5k
R2 SQR N001 20k
C2 SQR N001 10p
R4 N002 N003 470
XU5 N001 0 +15 -15 SQR LT1007 ;pnba In+)In-)V+)V-)OUT
R6 N001 TRI 10k
V2 +15 0 +15
V3 -15 0 -15
V1 N012 0 PULSE(-3 -3 0 1)
J2 N004 N011 SIN 2N3819
R8 SIN 0 680
R11 TRI N004 680
C1 TRI N002 1n
D2 N011 TRI 1N4148
D3 N011 0 1N4148
XU2 N009 SNIC +15 -15 N006 LT1001 ;pnba In+)In-)V+)V-)OUT
R3 N010 N003 470
R1 N009 N006 50k
R5 N006 SNIC 50k
R7 SNIC TRI 10k
D4 N014 SQR 1N4148
R14 N010 0 550
R15 N009 0 20k
.tran 0 1 1m startup

* LTspice schematic (.asc)
Version 4
SHEET 1 1888 736
WIRE 800 -336 800 -368
WIRE 944 -288 848 -288
WIRE 208 -272 176 -272
WIRE 304 -272 272 -272
WIRE 544 -224 544 -272
WIRE 544 -224 480 -224
WIRE 608 -224 544 -224
WIRE 800 -224 800 -256
WIRE 800 -224 752 -224
WIRE 848 -224 848 -288
WIRE 848 -224 800 -224
WIRE 912 -224 848 -224
WIRE -496 -192 -496 -224
WIRE -32 -192 -64 -192
WIRE 64 -192 32 -192
WIRE 176 -192 176 -272
WIRE 208 -192 176 -192
WIRE 304 -192 304 -272
WIRE 304 -192 288 -192
WIRE 608 -192 608 -224
WIRE 912 -192 912 -224
WIRE 480 -160 480 -224
WIRE 64 -144 64 -192
WIRE 304 -144 304 -192
WIRE -224 -128 -256 -128
WIRE -128 -128 -144 -128
WIRE -64 -128 -64 -192
WIRE -64 -128 -128 -128
WIRE 64 -96 64 -144
WIRE 80 -96 64 -96
WIRE 176 -96 176 -192
WIRE 176 -96 160 -96
WIRE 304 -96 304 -144
WIRE 336 -96 304 -96
WIRE 608 -96 608 -112
WIRE 752 -96 752 -224
WIRE 784 -96 752 -96
WIRE -496 -80 -496 -112
WIRE -496 -80 -544 -80
WIRE -448 -80 -496 -80
WIRE -256 -80 -256 -128
WIRE -256 -80 -384 -80
WIRE 912 -80 912 -112
WIRE 912 -80 848 -80
WIRE -672 -64 -704 -64
WIRE -576 -64 -592 -64
WIRE -64 -64 -64 -128
WIRE -32 -64 -64 -64
WIRE 176 -64 176 -96
WIRE 208 -64 176 -64
WIRE 784 -64 752 -64
WIRE -448 -48 -448 -80
WIRE -384 -48 -384 -80
WIRE 64 -48 64 -96
WIRE 64 -48 32 -48
WIRE 304 -48 304 -96
WIRE 304 -48 272 -48
WIRE -256 -32 -256 -80
WIRE -224 -32 -256 -32
WIRE -64 -32 -144 -32
WIRE -32 -32 -64 -32
WIRE 208 -32 176 -32
WIRE 480 -32 480 -96
WIRE 560 -32 480 -32
WIRE 912 -32 912 -80
WIRE -64 -16 -64 -32
WIRE -816 0 -864 0
WIRE -704 0 -704 -64
WIRE -704 0 -736 0
WIRE -576 0 -576 -64
WIRE -512 0 -576 0
WIRE -288 0 -320 0
WIRE 688 0 608 0
WIRE 176 16 176 -32
WIRE 480 16 480 -32
WIRE 608 16 608 0
WIRE -704 48 -704 0
WIRE -672 48 -704 48
WIRE -288 48 -288 0
WIRE -576 64 -576 0
WIRE -576 64 -608 64
WIRE -672 80 -704 80
WIRE -448 80 -448 48
WIRE -416 80 -448 80
WIRE -384 80 -384 48
WIRE -384 80 -416 80
WIRE -128 80 -128 -128
WIRE -64 80 -64 64
WIRE 752 80 752 -64
WIRE 832 80 752 80
WIRE 912 80 912 48
WIRE 912 80 832 80
WIRE -416 96 -416 80
WIRE -704 128 -704 80
WIRE 832 128 832 80
WIRE 16 144 -80 144
WIRE 336 144 336 -96
WIRE 336 144 80 144
WIRE 480 144 480 80
WIRE 608 144 608 96
WIRE -544 192 -544 -80
WIRE -512 192 -544 192
WIRE -416 192 -416 176
WIRE -416 192 -448 192
WIRE -128 192 -128 176
WIRE 832 240 832 208
WIRE -544 304 -544 192
WIRE -512 304 -544 304
WIRE -416 320 -416 192
WIRE -416 320 -448 320
WIRE -512 336 -544 336
WIRE -544 368 -544 336
FLAG 0 -16 -15
FLAG 0 -80 +15
FLAG 240 -80 -15
FLAG 240 -16 +15
FLAG 176 16 0
FLAG -64 80 0
FLAG -128 192 0
FLAG -480 288 +15
FLAG -480 352 -15
FLAG -288 48 0
FLAG -496 -224 +15
FLAG -640 96 -15
FLAG -640 32 +15
FLAG -704 128 0
FLAG -944 0 0
FLAG 64 -144 TRI
FLAG 176 320 0
FLAG 256 320 0
FLAG 256 240 -15
FLAG 176 240 +15
FLAG 480 144 0
FLAG 608 144 0
FLAG 544 -272 TRI
FLAG 688 0 SIN
FLAG 304 -144 SQR
FLAG 816 -48 -15
FLAG 816 -112 +15
FLAG -544 368 0
FLAG 800 -368 TRI
FLAG 944 -288 SNIC
FLAG 832 240 0
SYMBOL Opamps\\LT1001 0 -112 R0
SYMATTR InstName U1
SYMBOL njf -80 80 M0
SYMATTR InstName J1
SYMATTR Value 2N3819
SYMBOL npn -320 -48 M0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL npn -512 -48 R0
SYMATTR InstName Q2
SYMATTR Value 2N3904
SYMBOL Opamps\\LT1001 -480 256 R0
SYMATTR InstName U3
SYMBOL res -432 80 R0
SYMATTR InstName R10
SYMATTR Value 2k
SYMBOL cap -448 176 R90
SYMATTR InstName C3
SYMATTR Value 100p
SYMBOL res -512 -208 R0
SYMATTR InstName R12
SYMATTR Value 1Meg
SYMBOL Opamps\\LT1001 -640 0 R0
SYMATTR InstName U4
SYMBOL res -576 -80 R90
SYMATTR InstName R9
SYMATTR Value 1k
SYMBOL res -720 -16 R90
SYMATTR InstName R13
SYMATTR Value 55.5k
SYMBOL res 304 -208 R90
SYMATTR InstName R2
SYMATTR Value 20k
SYMBOL cap 272 -288 R90
SYMATTR InstName C2
SYMATTR Value 10p
SYMBOL res -128 -144 R90
SYMATTR InstName R4
SYMATTR Value 470
SYMBOL Opamps\\LT1007 240 16 M180
SYMATTR InstName U5
SYMBOL res 176 -112 R90
SYMATTR InstName R6
SYMATTR Value 10k
SYMBOL voltage 176 224 R0
SYMATTR InstName V2
SYMATTR Value +15
SYMBOL voltage 256 224 R0
SYMATTR InstName V3
SYMATTR Value -15
SYMBOL Misc\\signal -848 0 R90
SYMATTR InstName V1
SYMATTR Value PULSE(-3 -3 0 1)
SYMBOL njf 560 -96 R0
SYMATTR InstName J2
SYMATTR Value 2N3819
SYMBOL res 592 0 R0
SYMATTR InstName R8
SYMATTR Value 680
SYMBOL res 592 -208 R0
SYMATTR InstName R11
SYMATTR Value 680
SYMBOL cap 32 -208 R90
SYMATTR InstName C1
SYMATTR Value 1n
SYMBOL diode 496 -96 R180
SYMATTR InstName D2
SYMATTR Value 1N4148
SYMBOL diode 496 16 M0
SYMATTR InstName D3
SYMATTR Value 1N4148
SYMBOL Opamps\\LT1001 816 -144 R0
SYMATTR InstName U2
SYMBOL res -128 -48 R90
SYMATTR InstName R3
SYMATTR Value 470
SYMBOL res 928 64 R180
SYMATTR InstName R1
SYMATTR Value 50k
SYMBOL res 928 -96 R180
SYMATTR InstName R5
SYMATTR Value 50k
SYMBOL res 816 -240 R180
SYMATTR InstName R7
SYMATTR Value 10k
SYMBOL diode 16 160 R270
SYMATTR InstName D4
SYMATTR Value 1N4148
SYMBOL res -80 -32 R0
SYMATTR InstName R14
SYMATTR Value 550
SYMBOL res 816 112 R0
SYMATTR InstName R15
SYMATTR Value 20k