Boxcar FIR Filter

1
Boxcar FIR Filter

• Shadi Hawawini
• Pearl Yuan
• Amr Darwish
• Karun Malhotra
• Advisor Dr. Parent
• May 8, 2006

2
Agenda

• Abstract
• Introduction
• Why
• Simple Theory
• Background Information
• Summary of Results
• Project (Experimental) Details
• Results
• Cost Analysis
• Conclusions

3
Abstract

• We designed a 4-bit Finite Impulse Response (FIR)
  Filter that operates at 200 MHz
• Impulse Response - A set of FIR coefficients,
  which represent all possible frequencies.
• Tap - A coefficient/delay pair. The number of FIR
  taps is an indication of the amount of memory
  required to implement the filter.

4
Introduction

• One of the most fundamental elements for a DSP
  system is an FIR Filter.
• There is no feedback, which results in a finite
  output value of zero.
• The filter is mathematically expressed using the
  following difference equation

5
FIR Block Diagram

• The FIR Filter consist of three main components
• 1) A D Flip-Flop to implement a simple delay.
• 2) A Multiplier to implement the coefficients,
  which in our case we are using a Boxcar filter,
  meaning all coefficients are 1.
• 3) A Full adder to sum the nodes at the end of
  each Tap.

6
Longest Path Calculations
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Schematic
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Layout
9
Successful DRC check
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Successful Extraction Report
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Successful LVS Report
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Successful LVS Report cont.
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Simulations
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Simulations
15
Simulation
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Simulation
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Post Extraction
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Post Extraction cont.
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Propagation Delay Waveform
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Propagation Delay
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Cost Analysis

• Estimated time spent on each phase of the
  project
• Verifying Logic 2 weeks
• Verifying Timing N/A
• Layout 15 hours
• Post Extracted Timing 5 hours

22
Lessons Learned

• A project of this nature requires ample time to
  complete it, before its deadline.
• Verify logic of individual components.
• Extra care needed when designing the layout.

23
Summary

• Because FIR Filters are such an important element
  of DSP design, it was beneficial to do a project
  like this to strengthen understanding of the
  concept
• A low cost, easy to implement Boxcar FIR filter
  was designed and tested
• Due to the nature of DSP, FIR filters of some
  form will always be needed.

24
Acknowledgements

• Dr. Parent, for teaching us not to overcomplicate
  our designs.