* SPICE netlist
D1 Signal_1 OR_out 1N4148
D2 Signal_2 OR_out 1N4148
R1 OR_out 0 10k
D3 AND_out Signal_1 1N4148
D4 AND_out Signal_2 1N4148
R2 Vcc AND_out 10k
V1 Vcc 0 12
V2 Signal_1 0 PULSE(0 12 0 1n 1n 1 2 1)
V3 Signal_2 0 PULSE(0 12 0.5 1n 1n 1 2 1)
R3 Vcc NOT_out 10k
Q1 NOT_out N004 0 0 2N3904
R4 N004 Signal_1 1k
R12 Vcc XOR_out 10k
Q6 XOR_out N003 0 0 2N3904
R13 N003 N001 1k
Q7 N001 N002 Signal_2 0 2N3904
Q8 N001 N005 Signal_1 0 2N3904
R14 N005 Signal_2 10k
R15 N002 Signal_1 10k
R16 Vcc N001 10k
.tran 3

* LTspice schematic (.asc)
Version 4
SHEET 1 1328 1136
WIRE -664 -536 -664 -568
WIRE -520 -536 -520 -552
WIRE -184 -536 -184 -552
WIRE -664 -424 -664 -456
WIRE -520 -424 -520 -456
WIRE -184 -424 -184 -456
WIRE -552 -248 -616 -248
WIRE -408 -248 -488 -248
WIRE -312 -248 -408 -248
WIRE 152 -200 152 -248
WIRE -552 -136 -616 -136
WIRE -408 -136 -408 -248
WIRE -408 -136 -488 -136
WIRE -408 -72 -408 -136
WIRE 24 -72 -40 -72
WIRE 152 -72 152 -120
WIRE 152 -72 88 -72
WIRE -408 40 -408 8
WIRE 24 40 -40 40
WIRE 152 40 152 -72
WIRE 152 40 88 40
WIRE 248 40 152 40
WIRE 600 248 600 200
WIRE -360 296 -360 248
WIRE 232 296 152 296
WIRE 328 296 328 264
WIRE -72 344 -88 344
WIRE -40 344 -72 344
WIRE 88 344 40 344
WIRE 600 344 600 328
WIRE 664 344 600 344
WIRE 600 360 600 344
WIRE -360 392 -360 376
WIRE -296 392 -360 392
WIRE -360 408 -360 392
WIRE 232 408 232 296
WIRE 328 408 328 376
WIRE 328 408 232 408
WIRE 408 408 328 408
WIRE 536 408 488 408
WIRE -552 456 -600 456
WIRE -424 456 -472 456
WIRE 328 456 328 408
WIRE 600 488 600 456
WIRE 152 504 152 392
WIRE 152 504 104 504
WIRE 168 504 152 504
WIRE 264 504 248 504
WIRE -360 536 -360 504
WIRE -72 568 -72 344
WIRE 328 568 328 552
WIRE 328 568 -72 568
FLAG -408 40 0
FLAG -520 -424 0
FLAG -664 -424 0
FLAG -664 -568 Vcc
FLAG 152 -248 Vcc
FLAG -184 -424 0
FLAG -520 -552 Signal_1
FLAG -184 -552 Signal_2
FLAG -616 -248 Signal_1
FLAG -40 -72 Signal_1
FLAG -616 -136 Signal_2
FLAG -40 40 Signal_2
FLAG 248 40 AND_out
FLAG -312 -248 OR_out
FLAG -360 248 Vcc
FLAG -360 536 0
FLAG -600 456 Signal_1
FLAG -296 392 NOT_out
FLAG 600 200 Vcc
FLAG 600 488 0
FLAG 328 264 Vcc
FLAG -88 344 Signal_1
FLAG 104 504 Signal_2
FLAG 664 344 XOR_out
SYMBOL diode -552 -232 R270
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL diode -552 -120 R270
SYMATTR InstName D2
SYMATTR Value 1N4148
SYMBOL res -424 -88 R0
SYMATTR InstName R1
SYMATTR Value 10k
SYMBOL diode 88 -88 R90
SYMATTR InstName D3
SYMATTR Value 1N4148
SYMBOL diode 88 24 R90
SYMATTR InstName D4
SYMATTR Value 1N4148
SYMBOL res 136 -216 R0
SYMATTR InstName R2
SYMATTR Value 10k
SYMBOL voltage -664 -552 R0
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL voltage -520 -552 R0
SYMATTR InstName V2
SYMATTR Value PULSE(0 12 0 1n 1n 1 2 1)
SYMBOL voltage -184 -552 R0
SYMATTR InstName V3
SYMATTR Value PULSE(0 12 0.5 1n 1n 1 2 1)
SYMBOL res -376 280 R0
SYMATTR InstName R3
SYMATTR Value 10k
SYMBOL npn -424 408 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL res -456 440 R90
SYMATTR InstName R4
SYMATTR Value 1k
SYMBOL res 584 232 R0
SYMATTR InstName R12
SYMATTR Value 10k
SYMBOL npn 536 360 R0
SYMATTR InstName Q6
SYMATTR Value 2N3904
SYMBOL res 504 392 R90
SYMATTR InstName R13
SYMATTR Value 1k
SYMBOL npn 88 296 R0
SYMATTR InstName Q7
SYMATTR Value 2N3904
SYMBOL npn 264 456 R0
SYMATTR InstName Q8
SYMATTR Value 2N3904
SYMBOL res 264 488 R90
SYMATTR InstName R14
SYMATTR Value 10k
SYMBOL res 56 328 R90
SYMATTR InstName R15
SYMATTR Value 10k
SYMBOL res 312 280 R0
SYMATTR InstName R16
SYMATTR Value 10k