Abstract for group GuitarEffects

Our project for this class will be to produce a Real-Time Guitar
Effects Sampler. It is common for electric guitar players to make use
of `pedals' in order to achieve certain effects such as
`distortion/overdrive', `delay/echo', `chorus', `flanger' and
`pitch/phase shifter.' Typically these pedals make use of analog
electronics to yield the desired effect. In our case, we will be using
the Altera DE2 FPGA board as a sampler and DSP (Digital Signal
Processor). The idea is to have the user be able to select the desired
effect on the fly and have his audio stream modified in
real-time. Furthermore, as the board will be processing the signal
digitally, we also plan on outputting the waveform onto an SD
card. That way the user will have saved a digital copy of the modified
digital stream he heard while playing. This allows the user to record
his performance on the go and later edit it if needed with an audio
suite on a PC or Mac.

DE2 board aside, the setup will consist of a Vacuum Tube Preamp (ART
Tube MP Studio -- using a 12AX7 tube) in addition to the obvious
guitar that will be used for testing. We are likely to initially focus
on implementing three or four of the aforementioned guitar
effects. The methodology for proceeding with this endeavor can be
broken up into three parts: getting the DE2 to yield a digital stream
via the ADC, implementing the effects in question and then dumping the
processed data onto the SD card.

We are quite fortunate that the first part may already be taken care
of as a former student (Ari Klein) provided us with modified Verilog
code obtained from Cornell University that effectively implements a
CODEC. Hence, once we are through with testing that we can focus on
implementing the effects and controlling the SD slot.  In the event
that we are able to accomplish all of our expected goals prior to the
deadline, we will attempt to add other features that would be of use
to the musician.  For example, one logical addition would be a
playback function among other things...