Version 4
SHEET 1 2912 1300
WIRE -208 48 -208 16
WIRE -208 160 -208 128
WIRE -160 16 -208 16
WIRE 16 96 16 48
WIRE 16 192 16 96
WIRE 16 320 16 272
WIRE 64 16 -160 16
WIRE 64 48 16 48
WIRE 176 16 128 16
WIRE 384 -16 336 -16
WIRE 384 48 336 48
WIRE 416 -16 384 -16
WIRE 416 48 384 48
WIRE 624 -16 576 -16
WIRE 624 -16 624 -112
WIRE 624 48 576 48
WIRE 624 144 624 48
WIRE 672 -112 624 -112
WIRE 672 144 624 144
WIRE 736 -32 736 -48
WIRE 736 64 736 48
WIRE 736 224 736 208
WIRE 736 320 736 304
WIRE 816 -112 800 -112
WIRE 816 144 800 144
WIRE 864 -112 816 -112
WIRE 864 144 816 144
WIRE 1072 -112 1024 -112
WIRE 1072 -16 1072 -112
WIRE 1072 144 1024 144
WIRE 1072 144 1072 48
WIRE 1088 -16 1072 -16
WIRE 1088 48 1072 48
WIRE 1280 -16 1248 -16
WIRE 1280 48 1248 48
WIRE 1472 112 1472 48
WIRE 1472 240 1472 192
WIRE 1536 16 1440 16
WIRE 1536 48 1472 48
WIRE 1568 -128 1568 -176
WIRE 1600 -224 1552 -224
WIRE 1600 -176 1568 -176
WIRE 1648 -240 1648 -272
WIRE 1648 -128 1568 -128
WIRE 1648 -128 1648 -160
WIRE 1648 -96 1648 -128
WIRE 1680 16 1600 16
WIRE 1792 -272 1648 -272
WIRE 1792 -240 1792 -272
WIRE 1792 -128 1648 -128
WIRE 1792 -128 1792 -176
WIRE 1856 -272 1792 -272
WIRE 1872 80 1872 48
WIRE 1872 208 1872 160
WIRE 1936 48 1872 48
WIRE 1968 16 1840 16
WIRE 1968 48 1936 48
WIRE 2080 16 2032 16
WIRE 2096 16 2080 16
WIRE 2160 128 2160 80
WIRE 2160 272 2160 208
WIRE 2240 16 2224 16
FLAG -208 160 0
FLAG -160 16 b_in
FLAG 736 64 0
FLAG 736 320 0
FLAG 816 -112 x
FLAG 816 144 y
FLAG 16 320 0
FLAG 16 96 chip
FLAG 384 -16 x1
FLAG 384 48 y1
FLAG 624 -16 x2
FLAG 624 48 y2
FLAG 2080 16 x3
FLAG 1472 240 0
FLAG 2240 16 x4
IOPIN 2240 16 Out
FLAG 1872 208 0
FLAG 1936 48 ref
FLAG 2160 272 0
FLAG 1648 -96 0
FLAG 1856 -272 BER
IOPIN 1856 -272 Out
FLAG 1552 -224 x4
IOPIN 1552 -224 In
SYMBOL bv -208 32 R0
WINDOW 3 -24 158 Left 0
SYMATTR Value V=rand(time*{rb})>=0.5
SYMATTR InstName B1
SYMBOL ButterwLPF_3th 944 -112 R0
SYMATTR InstName X3
SYMATTR SpiceLine f={fc}
SYMBOL ButterwLPF_3th 944 144 R0
SYMATTR InstName X4
SYMATTR SpiceLine f={fc}
SYMBOL bv 736 -48 R0
SYMATTR InstName B7
SYMATTR Value V={Un}*Gauss1()
SYMBOL bv 736 208 R0
SYMATTR InstName B8
SYMATTR Value V={Un}*Gauss2()
SYMBOL add 736 144 R0
SYMATTR InstName X6
SYMBOL add 736 -112 R0
SYMATTR InstName X5
SYMBOL bv 16 176 R0
WINDOW 3 19 104 Left 0
SYMATTR Value V=(rand(time*{rc}+731.5)>=0.5)
SYMATTR InstName B13
SYMBOL Digital\\xor 112 -32 R0
SYMATTR InstName A7
SYMBOL pulse_shaping 496 16 R0
WINDOW 39 -66 70 Left 0
SYMATTR SpiceLine Td={Ts/2}
SYMATTR InstName X8
SYMBOL bv 1472 96 R0
WINDOW 3 -243 110 Left 0
SYMATTR Value V=delay(V(chip), {Tg+3/rc+45n+Ts/10})
SYMATTR InstName B2
SYMBOL Digital\\xor 1584 -32 R0
SYMATTR InstName A1
SYMBOL bv 1872 64 R0
WINDOW 3 -151 193 Left 0
SYMATTR Value V=delay(V(b_in), {Tg+2/rb-1/rc+60n})
SYMATTR InstName B3
SYMBOL voltage 2160 112 R0
WINDOW 3 -293 207 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR Value PULSE(0 1 {Tg+3/rb-1/rc+50n} {Ts/10} {Ts/10} 0 {1/rb})
SYMATTR InstName V1
SYMBOL Digital\\xor 2016 -32 R0
SYMATTR InstName A2
SYMBOL mult 2160 16 R0
SYMATTR InstName X1
SYMBOL g 1648 -256 R0
SYMATTR InstName G1
SYMATTR Value 1
SYMBOL cap 1776 -240 R0
SYMATTR InstName C1
SYMATTR Value {(Ts/10)*((Tmax-2/rb)*rb)}
SYMBOL pulse_reshaping 1168 16 R0
WINDOW 39 -67 70 Left 0
SYMATTR SpiceLine Td={Tg+Ts/2}
SYMATTR InstName X2
SYMBOL oqpsk_demod 1360 16 R0
WINDOW 39 -70 70 Left 0
SYMATTR SpiceLine Td={Tg+45n-Ts/10} ref=0
SYMATTR InstName X9
SYMBOL bpsk_demod 1760 16 R0
WINDOW 39 -163 71 Left 0
SYMATTR SpiceLine Td={Tg+1/rb-1/rc+45n} ref=4
SYMATTR InstName X10
SYMBOL serial_to_par 256 16 R0
WINDOW 39 -65 69 Left 0
SYMATTR SpiceLine Td=0
SYMATTR InstName X11
TEXT 896 -304 Center 0 ;Coherent O-QPSK system  (equivalent baseband)
TEXT 136 -312 Left 0 !.params\n+ fc = 1.25e6\n+ rb=250e3\n+ rc=2e6\n+ Ts=1/(6*rc)\n+ fIF=3e6
TEXT -226 -238 Left 0 !.tran 0 {Tmax} {Tmax-Ts} {Ts}
TEXT -224 -184 Left 0 !.options nomarch
TEXT -224 -112 Left 0 !.save V(BER)
TEXT -144 112 Left 0 ;bits in
TEXT 288 -200 Left 0 ;Ts = sample-rate
TEXT 536 -248 Left 0 !.func Gauss1() sqrt(-2*ln(1e-5+rand(2*time/{Ts})))*sin(2*pi*rand(2*time/{Ts}+2.43e4))
TEXT 536 -216 Left 0 !.func Gauss2() sqrt(-2*ln(1e-5+rand(2*time/{Ts})))*cos(2*pi*rand(2*time/{Ts}+2.43e4))
TEXT 136 -128 Left 0 !.params\n+ Tg =265n
TEXT 288 -104 Left 0 ;Tg = groupdelay of LPF
TEXT -224 -280 Left 0 !.params Tmax = 0.1
TEXT 336 -304 Left 0 !.params Un = 2.4
TEXT 1008 288 Left 0 ;C = 0.94 V^2\nN = 1.076 V^2 in a bandwidth of 3 MHz\n \nC/Nrx = -0.6 dB for a BER = 1e-3
RECTANGLE Normal 1376 400 992 256