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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

EE 4900: Fundamentals of Sensor Design

Lecture 14Sensors and Digital Signal Processing (DSP)

Part 2: DSP Algorithms

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

DSP: Basic Modules

Digital Signal Processing Algorithms

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

Digital Signal Processing Application and Algorithms

DSP Algorithms and their usage

Ref: Applied Digital Signal Processing: Theory and Practice, by D. Manolakis and V. K. Ingle

Application DSP Algorithm

Audio/Speech ProcessingCompression/Decompression, equalization, mixing, sound

synthesis, noise cancellation, stereo and surround sound

Image/Video Processingcompression/decompression, enhancement, video coding,

motion detection, image reconstruction

Transmission of audio,

video, data

modulation/demodulation, error correction coding,

encryption/decryption, echo cancelation, multipath

equalization, cellular networking algorithms

Military/Tactical Systemsnavigation, beamforming, radar and sonar processing,

software defined radio

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

Image Compression and Decompression

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

Audio Compression and Decompression

Differential Pulse Code Modulation (DPCM)

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

Image Reconstruction

Dr. Larry Zeng's Research (Filtered Backprojection Algorithm)

Airport Bag Scans

Low Dosage Clinical CT

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

Modulation/Demodulation

Communications (FSK, BPSK, QPSK, etc..)

Binary Phase Shift Keying (BPSK)

1) Phase of the carrier changes depeneding on the data, e.g. 0 deg for 1 and 180 deg for 0

2) Robust to noise, BPSK is coherent as the phase transitions occur at the zero crossing

pointsOut of phase

component Q (sine)

In-phase

component I (cosine)

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

BPSK Modulation/Demodulation

Modulation

Demodulation Low Pass Filter

BPSK Signal

Matlab Central: BPSK modulator http://www.mathworks.com/matlabcentral/fileexchange/12691-bpsk-modulation

BPSK Demodulator http://www.mathworks.com/matlabcentral/fileexchange/25243-bpsk-demodulator

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

Filtering

Filters are signal conditioners

Filters are signal conditioners

Filter by accepts an input signal, blocks prespecified frequency

components, and passes the original signal minus those components

to the output

Types of Filters

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

Filtering

Low Pass Filter Types

Four major types (IIR): Butterworth, Chebyshev, Elliptic, Bessel

Filter phase response is important. Why?

Amplitude Response Phase Response

Check in Matlab

(type fdatool )

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

IIR Filter

Infinite Impulse Response (IIR) Filter1) Feedback, recursive: current output depends on previous outputs

2) Implemented by using a series of delays, multipliers, and adders

Tap

X

+

Delay

bM

xn

Xb2

+

Delay

Xb1...

+

Delay

Xb0

yn

Numerator

Coefficients

01100110 ...... xbxbxbyayaya MnnMnn

M-1 delays

Filter Order= M

X

+

Delay

-aMX-a2

+

Delay

X-a1

+

Delay

X-a0

Denominator

Coefficients

...

+

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

FIR Filter

Finite Impulse Response (FIR) Filter

1) No feedback

2) Implemented by using a series of delays, multipliers, and adders

Tap

X

+

Delay

bM

xn

Xb2

+

Delay

Xb1...

+

Delay

Xb0

yn

Numerator

Coefficients

0110 ... xbxbxby Mnnn

M-1 delays

Filter Order= M

b0xn

b1xn-1b2xn-2bMx0

Note: 1) Delay =1 clock delay in DSP FPGA/Microprocessor

2) Tap is implemented by Multiply-accumulator (MAC) unit in DSP

Microprocessor

Design an FIR Filter in Matlab

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ECE 5900/6900 Fundamentals of Sensor Design Dr. Suketu Naik

FIR Filter Implementation

Finite Impulse Response (FIR) Filter (more common)

Implement an FIR Filter in Microprocessor

Arduino

http://www.arduinoos.com/2011/07/fir-filters-part-1/

Spartan3

http://www.xilinx.com/products/intellectual-property/fir_compiler.html#overview

Raspberry PI

https://volumio.org/forum/dsp-with-raspberry-hifiberry-and-volumio-drc-folve-t672.html

SiLabs C8051F020DK MCU Kit

?

Microchip PIC18 Microcontroller

http://ww1.microchip.com/downloads/en/AppNotes/00852a.pdf