SMPS

Total current dissipation is 479mA (refer to the power budget).
Unfortunately the USB bus can only provide ~300mA. So we need external power.

1. ADC - single supply +5V
2. DDS - dual supply +1.8V, +3.3V
3. Z8 - single supply +3.3V
4. SPARTAN3 - multi supply +3.3V,+2.5V,+1.2V
5. PROM -single supply +1.8V, -read this
   
6. line driver - single supply +5V
7. attenuator - single supply +5V
8. FT245R - single supply +5V
9. LCD - single supply +5V

So we need 5 regulators. The 3.3V and the 5V regulator must also provide high load currents ,~2A.