1. ADC – FIR Filter – DAC KEVIN COOLEY

2. Overview  Components  Schematic  Hardware Design Considerations  Digital Filters/FPGA Design Tools  Questions

3. Analog Devices AD9283  8-bit resolution ADC  50 MSPS/80 MSPS/100 MSPS  475 MHz Analog Bandwidth  TTL/CMOS Compatible Digital Outputs and Clock (Encoder) Input Image Source: www.analog.com

4. Analog Devices AD9708  8-bit resolution DAC  125 MSPS Update Rate  Differential Current Outputs  CMOS Digital Inputs Image Source: www.analog.com

5. Field Programmable Gate Array (FPGA) Field Programmable Gate Arrays (FPGAs) are semiconductor devices that are based around a matrix of configurable logic blocks (CLBs) connected via programmable interconnects. FPGAs can be reprogrammed to desired application or functionality requirements after manufacturing. Source: www.Xilinx.com Image Source: http://www2.hdl.co.jp/

6. FPGA Basics  Easily create and connect complicated digital structures  Shift registers  Logic gates (AND/OR/NOR, etc.)  Multipliers/Adders/Accumulators  State machines  Digital filters  Massively parallel processing  Each data path has dedicated hardware  No competition for resources

7. Overview  Components  Schematic  Hardware Design Considerations  Digital Filters/FPGA Design Tools  Questions

10. Overview  Components  Schematic  Hardware Design Considerations  Digital Filters/FPGA Design Tools  Questions

11. High-Speed Digital Bus Routing  Route each trace as stripline  Signal traces must be length- matched to keep signal skew within tolerance  Rounded length-matching structures are less likely to radiate than structures with hard right-angles.  Differential pairs need to be length-matched and routed together.

12. High-Speed Digital Bus Routing PCB design tools help ensure that “skew group” routing rules are followed.

13. Overview  Components  Schematic  Hardware Design Considerations  Digital Filters/FPGA Design Tools  Questions

14. Digital Filters: Infinite Impulse Response (IIR) Filter Has a recursive term (feedback)

15. Static Timing Analysis  Everything has to happen in one 10ns period.  FPGA tools identify critical path.  Pipelining is impossible because of the recursive nature of the filter.

16. Static Timing Analysis

18. Digital Filters: Finite Impulse Response (FIR) Filter No feedback required!

19. Even Better: Add Pipelining

20. Questions?

21. References Johnson, H., & Graham, M. (1993). High-Speed Digital Design A Handbook of Black Magic. Upper Saddle River: Prentice Hall. Mitra, S. K. (2011). Digital Signal Processing A Computer-Based Approach. New York: McGraw-Hill.