Version 4
SHEET 1 1652 680
WIRE 80 80 16 80
WIRE 528 80 464 80
WIRE 16 112 16 80
WIRE 464 112 464 80
WIRE 16 224 16 192
WIRE 464 224 464 192
WIRE 528 304 464 304
WIRE 64 320 0 320
WIRE 464 336 464 304
WIRE 0 352 0 320
WIRE 464 448 464 416
WIRE 0 464 0 432
FLAG 464 224 0
FLAG 16 224 0
FLAG 528 80 rand2
IOPIN 528 80 Out
FLAG 80 80 rand1
IOPIN 80 80 Out
FLAG 0 464 0
FLAG 64 320 rand3
IOPIN 64 320 Out
FLAG 464 448 0
FLAG 528 304 rand4
IOPIN 528 304 Out
SYMBOL bv 464 96 R0
SYMATTR InstName B1
SYMATTR Value V=rand(time*1K+10k+{100*mc(1,1)})
SYMBOL bv 16 96 R0
SYMATTR InstName B3
SYMATTR Value V=rand(time*1K+{100*mc(1,1)})
SYMBOL bv 0 336 R0
SYMATTR InstName B2
SYMATTR Value V=rand(time*1K+20k+{100*mc(1,1)})
SYMBOL bv 464 320 R0
SYMATTR InstName B4
SYMATTR Value V=rand(time*1K+30k+{100*mc(1,1)})
TEXT -8 -160 Left 2 !.tran 0 30m\n.options maxstep=10u
TEXT -8 32 Left 2 ;rectangular  0 to +1.0
TEXT -8 -72 Left 2 !.options plotwinsize=0
TEXT 280 -72 Left 2 ;Outpput data compression off
TEXT 280 -160 Left 2 ;Plot step time <0.01*1/FREQUENCY. \nFREQUENCY is 1KHz in this example
TEXT -24 544 Left 2 ;Option for a random start of each simulation with mc()\nControl Panel -> Hacks \nUse the clock to reseed the MC generator [x]