diff --git a/readme.md b/readme.md index 61b74e9..1b34c1d 100644 --- a/readme.md +++ b/readme.md @@ -13,6 +13,28 @@ Potential applications for this design include: analog features - Projects where you don't like using IP and prefer to write things yourself +## Demonstration + +For demonstrating sound in / sound out, I decided to port a portion of a school project from my +Junior year of college: a crude octave up / down pitch shifter. I added the effect into the same +hardware test design and made it controllable with a few tactile switches. + +On the analog side, an AUX cable was hooked up from the breadboard to the function generator and a +class-AB amplifier was added to the DAC for driving an 8ohm speaker. Finally, a .wav file of some +dialogue was played, and the effect was successfully tested. + +![Image](/doc/amp.png) + +I was pretty happy with my result, and surprised that I had a decent demonstration of digitizing +sound with only three resistors and two capacitors. + +CTRL+click the video thumbnails to open in a new tab + +| Youtube Videos | +| :--: | +| *Sigma-Delta A/D Converters in FPGA* | +| [![Image](/doc/vid01_tb.png)](https://youtu.be/dKhM7zcvpbM) | + ## Results The results of the project were successful, resulting in low resource ADC and DAC designs that could @@ -226,28 +248,6 @@ cd hw ./hw.py -h ``` -## Demonstration - -For demonstrating sound in / sound out, I decided to port a portion of a school project from my -Junior year of college: a crude octave up / down pitch shifter. I added the effect into the same -hardware test design and made it controllable with a few tactile switches. - -On the analog side, an AUX cable was hooked up from the breadboard to the function generator and a -class-AB amplifier was added to the DAC for driving an 8ohm speaker. Finally, a .wav file of some -dialogue was played, and the effect was successfully tested. - -![Image](/doc/amp.png) - -I was pretty happy with my result, and surprised that I had a decent demonstration of digitizing -sound with only three resistors and two capacitors. - -CTRL+click the video thumbnails to open in a new tab - -| Youtube Videos | -| :--: | -| *Sigma-Delta A/D Converters in FPGA* | -| [![Image](/doc/vid01_tb.png)](https://youtu.be/dKhM7zcvpbM) | - ## Implementation Below are my notes and ramblings about how the design was implemented. @@ -272,8 +272,6 @@ the comb stages can be repeated (cascaded) multiple times to achieve even better The main benefit of a CIC filter is its use in multirate systems as you can achieve large downsampling ratios with just adders and subtractors. - - ![Image](/doc/adc.png) The FIR compensator is an optional parameterized step in the ADC design to balance the roll-off