Lab 7 Instructions By Yeong Choo and Sam Kanawati The University of Texas at Austin, April 29, 2018

WinDSK Demonstration Connect your DSP board with the PC through the USB-UART cable. Hardware setup using auxiliary cable: Connect between your PC/ smart phone and audio line-in jack of the DSP board (Your PC/ smart phone as the digital audio signal source) Connect between the audio line-out jack of the DSP board and the oscilloscope Run “audio effects” in WinDSK, test different special effects through earphone Display the output of special effect on the oscilloscope, and show the FFT on one of the channel 1st checkpoint with TA when you have both screenshots ready Describe bandwidth of digital audio signal, any harmonics observed

DSK implementation Echo Effect Create a new project with the source files in “../chapter_10/ccs/Echo” You can only load one ISR file in your project at a time. You may also load multiple ISR file in your project but include only one for each project compilation To include only one ISR file in project build: Select the remaining ISRs, right click to “exclude from build” Run the program and listen to the echo effect generated by FIR and IIR comb filters. Display the original audio signals on one channel, the audio signals with echo effect on another channel Show the FFT on the channel with audio signal with echo effect 2nd checkpoint with TA when you have both screenshots ready Describe bandwidth of digital audio signal, any harmonics observed

DSK implementation Flanging Effect In this task you need to modify the code to implement the flanging effect. The flanging effect needs a FIR comb filter with a varying delay (equation given). Here we choose the maximum delay to be 1ms. So R = 48 (given that fs = 48 KHz). Set f0 in the equation to be 15 Hz. Modify the code in the original codes in the Echo effect ISR routine to implement this FIR comb filter with flanging effect. Display the original audio signals on one channel, the audio signals with flanging effect on another channel Show the FFT on the channel with audio signal with flanging effect 3rd checkpoint with TA when you have both screenshots ready Describe the effect of flanging parameters, R and fo, on the overall audio effect