It is an application of Multispectral Analysis

1. A Seminar on
High Qaulity Analog to Digital Conversion of Digital Audio
By
Mahesh Pawar
(MIS-121697010)

2. Multirate Signal Processing
• A digital Signal Processing system that uses signals with different sampling
frequencies is probably reforming Multirate Digital Signal Processing
• Multirate Digital Signal Processing often uses Sample Rate Conversion to convert
from One sampling Frequency to another Sampling Frequency
• Sample Rate Conversion Uses
Decimation to decrease the sampling rate
Interpolation to increase the sampling rate

3. Advantages Of Multirate DSP
• Reduction in Computations and Memory requirements
• The New Sampling Rate is arbitrarily selected and needn’t
have any special relationship to the old sampling rate
• Multirate DSP is more efficient, Distortion less and flexible type
of Signal Processing

4. Applications
• Compact Disc Player
• Subband Coding of Speech Signals
• Quadrature Mirror filters
• Transmultiplexers
• Acquisition of High Quality Data
• Interfacing of Digital Systems with diiferent sampling rates
• The Design and Implementation of Narrowband digital filtering
• Implementation of Digital Filter Banks
• High Resolution narrowband

5. 1. High Quality A/D conversion for Digital Audio
• Better Quality
• High resolution
• Higher Speed ADC
• Single-bit ADC’s using delta
sigma modulation techniques

6. 2. Audio Signal Reproduction in the Compact Disc
System

7. Components Of Audio Signal Reproduction
In the Compact Disc System
1. Laser Optical Pickup
 The Optical Pick Upunit is used to produce a speed reference signal
From a rotating component for timing and indexing
2. EFM Demodulation
 Eighttofourteen modulation (EFM) is a data encoding technique
3. Error Correction And Concealment
 Error Concealment is aims to minimize the deterioration of signals
Caused by missing data

8. 4. Time Base Correction
 time base correction is a technique to reduce or eliminate
errors caused by mechanical instability present in analog.
5. Oversampling
 There are three main reasons for performing Oversampling
1. Anti-aliasing
2. Resolution
3. Noise
 Used in reconstruction of signal
6. DAC
7. Loudspeaker
(Continued…)