Download GFX-One Guitar Processor

GFX-One Guitar
Processor
Team Carpal Tunnel
September 8, 2005
Capstone Fall 2005
Team Members
Mason Stone
 Henock Negassa
 Tony Sawyer
 Nael Cassier

Capstone Fall 2005
What is GFX-One?
GFX-One is a digital audio effects
processor.
 It is designed specifically for use with
guitar, but can process any monaural
analog audio input.

Capstone Fall 2005
Functional Block Diagram
Input
Box/User Interface
LCD +
Buttons
A/D
Analog to
Digital
converter
Guitar or
any other
analog
input
FLASH
FPGA
25MHz
Oscillator
DSP chip
D/A
Digital to
Analog
Converter
DRAM
Capstone Fall 2005
Output
Mixer
Digital Signal Processor
Capstone Fall 2005
Why use a DSP?
Digital data is easier to manipulate
 Implementing effects can be done using
algorithms and subroutines as opposed
to sophisticated analog hardware
 DSP can be altered and maintained
using software

Capstone Fall 2005
Implementing Audio Effects
Flanger effect is
present in a lot of
guitar-driven music

It is accomplished
by adding a signal to
a time-varying,
phase-modulated
version of itself
Amplitude

2
1.5
1
0.5
0
-0.5
-1
-1.5
-2
0
500
1000
1500
time
Capstone Fall 2005
2000
2500
Fixed Delay and Reverberation

Reverberation and echo
are very common in
audio engineering

Both can be synthesized
in DSP using comb
filters and re-circulating
delay lines
Capstone Fall 2005
Other Effects and Features
Parametric Equalization
 Gain manipulation
 Auto-Wah
 Phaser
 Noise-gating
 Decimation (Aliasing)
 Many other possibilities

Capstone Fall 2005
DSP Interface

What We Need:
– 25 MHz Oscillator
– Flash Microcontroller
– 256 MB SDRAM
– FPGA
– I/O
Capstone Fall 2005
25 MHz Oscillator



Used to synchronize
digital circuitry.
With use of PLL, provides
clock speed.
Will be connected to
FPGA, then distributed.
Capstone Fall 2005
Flash Microcontroller



Contains instructions for DSP.
Internal μcontroller programs
chip automatically over HDD
interface.
Internal code can contain
image for FPGA.
Capstone Fall 2005
SDRAM/FPGA

Operate over system bus:
– 8 bits for Address
– 8 bits for Data
– Chip Enable
– Read/Write Enable
– Clock
– IRQ
Capstone Fall 2005
Input/Output

DSP means Digital Signal
Processor, so we need a digital
input and output.
– A/D converter translates signal
into DSP.
– D/A converter translates signal
out of DSP.

DSP has Multi-channel Audio
Serial Ports (McASP) to
accomplish this, but it can also
be implemented using parallel
interface.
Capstone Fall 2005
Mixed Signal Interface
Signal from Analog amplifier is fed to A/D
Converter.
 Converts input voltage from analog signal
in to Digital bit
 Synchronized with 44.1KHz Clock
 16 Bit digital signal

Capstone Fall 2005
Mixed Signal Interface

Digital to Analog (D/A) conversion
methods
– Data is fed from DSP to D/A Converter.
– Standard D/A converters translate an array of
digital bits into a bias voltage
– Synchronized with 44.1KHz Clock
– 16 Bit digital signal
Capstone Fall 2005
Power
Regulated 3.3 and 2.5 V power buses from 9V
DC adapter.
 5V

– LCD

3.3 V
– Compact Flash
– A/D and D/A converters
– Data lines to and from FPGA

2.5 V
– FPGA Vcc
Capstone Fall 2005
Analog Signal Mixer
A good recording mixer lets you route a
variety of input signals and combine them
into one signal.
 For a potential Add-on output signal from
MP3 player will mix with signal from D/A
converter

Capstone Fall 2005
Audio Op Amps
Analog signal from
Mixer is going to be
amplified and routed
to speaker
 Amplifier is transistor
based
 1.6- to 3.6-volt
speaker driver

Capstone Fall 2005
Field Programmable Gate Array
Gateway of the user to all the other chips
 Controls the Clock to other devices
 Sends data to the DSP as well as the LCD
 Flash will set the FPGA through the DSP
 Program the FPGA through a JTAG
Interface

Capstone Fall 2005
User Interface
Power
In
Out
Mix
EQ
I/O
1
2
3
4
5
6
Bypass
Capstone Fall 2005
Schedule
Capstone Fall 2005
Division of Labor
Name
Task
Nael Cassier
Mason Stone
User Interface/FPGA
Configuration
DSP Integration
Tony Sawyer
DSP Core Implementation
Henock Negassa A/D Component Integration
Capstone Fall 2005
Tentative Budget
Component
Manufacturer / Part Number
Estimated Price
Digital Signal Processor
TI part # TMS320C6713
$100
FPGA Development Board
Xilinx Spartan3 # XC3S200
$300
Flash Microcontroller
Microchip # PIC16LF74/P
$60
Flash PROM
Xilinx # XC18V02
$50
SDRAM
Micron #MT48LC16M16A2
$50
A/D Converter
TI # ADS1625
$60
D/A Converter
TI
$60
25 MHz Oscillator
$40
LCD Display
Crystal Fontz #CFAH0802A
$50
Printed Circuit Boards
Advanced Circuits
$200
Push-Button User Interface
$45
Passive Components / Fixtures
J.B. Saunders
$200
9 V Power Supply
J.B. Saunders
$35
Analog Signal Mixer
$100
Miscellaneous (printing/binding
costs, posters, unforeseen parts,
add-ons, etc)
$250
Total
$1600
Capstone Fall 2005
Possible Add-ons
Add another analog signal (MP3)
 Amplifier + Speaker
 Over Drive Circuit

Input
Box/User Interface
LCD +
Buttons
Over Drive
Circuit
Guitar or
any other
analog
input
A/D
Analog to
Digital
converter
FLASH
FPGA
25MHz
Oscillator
DSP chip
D/A
Digital to
Analog
Converter
Output
Mixer
DRAM
Amplifier
Possible Add-on
MP3
player
(possible
Add-on)
Capstone Fall 2005
Risks and Contingencies
Hardware Availability/ Damage
 Difficulties Implementing FPGA
 Difficulties Implementing LCD
 Difficulties With DSP Interface Bus

Capstone Fall 2005
Questions?
Capstone Fall 2005