v4  7 0 pulse(0 5 0 0 0 5m 10m)
v3  5 0 pulse(0 5 0 0 0 10m 20m)
v2  8 0 pulse(0 5 0 0 0 20m 40m)
v1  4 0 pulse(0 5 0 0 0 40m 80m)
.model u5 d_xor
.model u5adc adc_bridge(in_low=0.8 in_high=2.0)
.model u5dac dac_bridge(out_low=0.25 out_high=5.0 out_undef=1.8 t_rise=0.5e-9 t_fall=0.5e-9)
