GFX-One Guitar Processor
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Transcript 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
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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
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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
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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
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Other Effects and Features
Parametric Equalization
Gain manipulation
Auto-Wah
Phaser
Noise-gating
Decimation (Aliasing)
Many other possibilities
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DSP Interface
What We Need:
– 25 MHz Oscillator
– Flash Microcontroller
– 256 MB SDRAM
– FPGA
– I/O
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25 MHz Oscillator
Used to synchronize
digital circuitry.
With use of PLL, provides
clock speed.
Will be connected to
FPGA, then distributed.
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Flash Microcontroller
Contains instructions for DSP.
Internal μcontroller programs
chip automatically over HDD
interface.
Internal code can contain
image for FPGA.
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SDRAM/FPGA
Operate over system bus:
– 8 bits for Address
– 8 bits for Data
– Chip Enable
– Read/Write Enable
– Clock
– IRQ
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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.
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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
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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
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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
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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
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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
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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
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User Interface
Power
In
Out
Mix
EQ
I/O
1
2
3
4
5
6
Bypass
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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)
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Risks and Contingencies
Hardware Availability/ Damage
Difficulties Implementing FPGA
Difficulties Implementing LCD
Difficulties With DSP Interface Bus
Capstone Fall 2005
Questions?
Capstone Fall 2005