1. Digital 5-Band Equalizer Electrical Engineering 113D Authors: Gordon Tsui Michael Kim

2. Digital Equalizer Used in Audio Processing and is the process of modifying the frequency envelope of sound Found in various programs such as WINAMP, Windows Media Player and any other application that requires digital audio processing. Number of bands vary on each equalizer

3. Development Modeled project after Experiment 2 Used MATLAB to obtain coefficients required for different filters Found impulse response to verify requirement needs Implemented assembly code and tested results

4. System Diagram

5. Impulse Response Specifications needed to meet a 1dB Ripple

6. Filter Specifications Our Equalizer consisted of 5-bands Low Pass0-2kHz Band Pass 11.6kHz-3.6kHz Band Pass 24.2kHz-7.2kHz Band Pass 37.7kHz-9.7kHz High Pass10.28khz and above

7. Filter Specifications Low Pass Filter – Magnitude Responses Difference seen between two due to anti-aliasing filter in DSP Board

8. Filter Specifications Band Pass Filter 1 – Magnitude Responses

9. Filter Specifications Band Pass Filter 2 – Magnitude Responses

10. Filter Specifications Band Pass Filter 3 – Magnitude Responses

11. Filter Specifications High Pass Filter – Magnitude Responses Difference seen between two due to F HP cutoff frequency

12. Assembly Code XGL.word 32767 ;the different gain values XGB.word 0;at the end of the.data section A = trcv ; load accumulator with word AR1=#XLP ; AR1 points to XLP and gets value of A *AR1=A AR1=#XBP;AR1 points to XBP and gets value of A *AR1=A AR3 = #XNLAST ;points to XNLAST A = #0 ;sets value of A to 0 repeat(#122) ;123 coefficients MACD(*AR3-,L0,A) ;same as experiment 2 *AR0 = hi(A) ;AR0 gets the MSB of A A=#0 ;sets value A to zero MACP(*AR0, XGL, A) ;multiplies values of at AR0 and XGL and stores in A *AR0 = hi(A) ;AR0 gets the MSB of A AR3 = #XNLASTB A = #0 repeat(#122) MACD(*AR3-,B0,A) *AR4 = hi(A) A=#0 MACP(*AR4, XGB, A) *AR4 = hi(A) A = *AR0 A = A + *AR4 ;the output of the two filters are added together tdxr = A ;value of A sent to output

13. Problems With Assembly Coding Initially had too many coefficients that the DSP board couldn’t handle Unable to use the @ operator Gain of 1*(2^15-1) reduces signal by factor of 2

14. Examples Audio Clip with unity Gain Applied High Pass Filter Applied Band Pass Filters Combination of Band Pass and High Pass Applied Low Pass Filter