Transcript Digital Processing of Audio Signals

Digital Processing of Audio
Signals
Prasanna Vemuri
Padma Parakala
Rekha Vemuri
Presentation Outline
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Objective
Product Idea
Development strategy
Design Phase
Alternate Approach
Cost Analysis
Time line
Conclusions
Objective
• The main objective of this project is to
design an audio amplifier and to process
the output signal using digital filtering
techniques
Product Idea???
What can be done to reduce noise?
Which process is more suitable?
Product Idea???
What are the resources available to
achieve the task?
• Is the product idea feasible and within the
economical constraints?
Development Strategy
Design Phase
Analog Audio Amplifier
Analog to Digital Conversion
ADH 0
From Output of
Audio Amplifier
NI BNC 2120 DAQ Board
Digital Filtering
Digital to Analog Conversion
DAC 0
To Speaker
NI BNC 2120 DAQ Board
Speaker
Limitations
• Hissing --- Lack of Precision equipment
• Time lag – Scan time for acquiring and
processing the data
Alternate Approach
FIR Filter
Alternate Approach Contd..
• To eliminate time lag
-- Using scan clock
-- Using case structure
• To eliminate hissing
-- IIR Filter with Scaled Window
Cost Analysis
Part
Description
Cost ($)
U1
LM386 Audio Power Amplifier Chip
0.55
R1
10 Resistor
0.15
C1
220f Electrolytic Capacitor
0.15
R2
1k Resistor
0.15
C2
10f Electrolytic Capacitor
0.10
R3
10k Resistor
0.15
Bypass
100pf Ceramic Capacitor
0.10
R4
10 Resistor
0.15
C4
0.05f Ceramic Capacitor
0.10
C3
220f Electrolytic Capacitor
0.15
E3631A
Triple Out DC Power Supply, HPIB/RS-232
1,122.00
BN2120
E-Series Multifunctional I/O DAQ
395.00
TOTAL
1518.75
Time Line
Conclusions
• Real time application of digital
filtering is more efficient for the
acquisitions at lower speeds
• Waveform graph after filtering
showed reduction in noise of the
audio signal
For more information
Visit us at:
www.cas.unt.edu/~prasanna/ELET5330