Digital signal processors (DSP)

pancakesbootΤεχνίτη Νοημοσύνη και Ρομποτική

24 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

125 εμφανίσεις

1

Digital signal processors
(DSP)

2

Content



Digital signal processing principles (4)


DSP Manufacturers


Architecture of DSP


Digital filters design and implementation


Other types of signal processing



3

Introduction to DSP


The goal of DSP is usually to measure, filter and/or
compress continuous real
-
world analog signals. The
first step is usually to convert the signal from an
analog to a digital form, by
sampling

it using
an

analog
-
to
-
digital converter

(ADC), which turns the
analog signal into a stream of numbers. However,
often, the required output signal is another analog
output signal, which requires a

digital
-
to
-
analog
converter

(DAC).


Even if this process is more complex than analog
processing and has a

discrete value range
,


the application of computational power to digital
signal processing allows for
many advantages over
analog processing
in many applications, such
as

error detection and correction

in transmission as
well as

data compression
.

4


advantages over analog processing:


All characteristics may be 100% repeated


Easy way to change any processing algorithm


Diminishing size (power supply and other features)
of device


Embedded diagnostics etc.



5


The main applications of DSP are



audio signal processing,



audio compression,



digital image processing,



video compression,


speech processing,



speech recognition,



Digital communications,



RADAR
,

SONAR
,

seismology

and

biomedicine
.


6

7


Specific examples are



transmission in digital

mobile phones
,



room correction

of sound in

hi
-
fi

and



sound reinforcement

applications,



analysis and control of

industrial processes
,



medical imaging

such as

CAT

scans


computer graphics
,

image manipulation
,


hi
-
fi
loudspeaker

crossovers

and

equalization
,
and

audio effects
.

Main manufacturers


Texas Instruments (TI)


Analog Devices


Motorola


Other firms

8

Firms Which uses DSP of TI


Xybernaut


Kodak


Nokia


3Com


e.Digital


SonyEricsson


Hewlett Packard


Sony


Palm

9

Charicteristics


С6211В:


1200
-

1336
MIPS


1,8 В


25,85
-

26,93 у.е.


С6201:


1600
MIPS



1,8 В


82,70
-

99,24 у.е.


С6416Т:


4800
-

8000
MIPS


1,1
-

1
,2 В


114,45
-

247,36
у.е.


С6411:


2400
MIPS



1,2 В


42,21 у.е.

С6713:

1000
-

1350
MFLOPS

1,26 В

23,25
-

28, 99
у.е.


10

11

ADSP
21
xx

core

Более детально структура
ADSP

приведена ниже

12


Double Harvard
architecture



Two data memories and two program memories
and doubled inside buses


the main features of
this architecture.

Block
-
diagram of

C6000

13

Introduction to signal
processing


There are two unequal types of signal processing


Linear (digital filtering)


Non
-
linear (all other methods)

14

Digital filtering


The design of digital filters is a deceptively complex
topic.

Although filters are easily understood and
calculated, the practical challenges of their design and
implementation are significant and are the subject of
much advanced research.


There are two categories of digital filter: the

recursive
filter

and the

nonrecursive filter
. These are often
referred to as

infinite impulse response

(IIR) filters
and

finite impulse response

(FIR) filters, respectively.

15

Digital filtering


The

impulse response

is the output of a system when the
input is an

impulse
.


In this same manner, the

step response

is the output
when the input is a

step

(also called an

edge
, and
an

edge response
). Since the step is the integral of the
impulse, the step response is the integral of the impulse
response.


This provides two ways to find the step response: (1)
feed a step waveform into the filter and see what comes
out, or (2) integrate the impulse response.

16


Digital filtering


To be mathematically correct:

integration

is used with
continuous signals, while

discrete integration
, i.e., a
running sum, is used with discrete signals).


The frequency response
can be found by taking the DFT
(using the FFT algorithm) of the impulse response.


The frequency response can be plotted on a linear
vertical axis, such as in (c), or on a logarithmic scale
(decibels), as shown in (d).

17

Parameters of filters

18

4 types of filters


Figs. 14
-
8 shows how
low
-
pass

and
high
-
pass filter
kernels can be combined to form
band
-
pass

and
band
-
reject

filters.


In short,

adding

the filter kernels produces a

band
-
reject


filter, while

convolving

the filter kernels
produces a
band
-
pass

filter. These are based on the
way cascaded and parallel systems are be combined.

19

4 types of filters

20

Impulse response

of digital filter


The

impulse response
, often denoted

h
[
k
]

or

h
k
, is a
measurement of how a filter will respond to
the

Kronecker delta

function. The impulse response is a
characterization of the filter's behaviour. Digital filters
are typically considered in two categories:

infinite
impulse response

(IIR) and

finite impulse
response

(FIR).


21

Difference equation



Linear form


Difference equation for IIR:




This equation shows how to compute the next
output sample,

y
[
n
], in terms of the past
outputs,

y
[
n



p
], the present input,

x
[
n
], and
the past inputs,

x
[
n



p
].


22

IIR filter realization
in

Direct Form I


The difference equation is evaluated directly. This
form is practical for small filters, but may be
inefficient and impractical (numerically unstable) for
complex designs

23

Filters classification


There are many different methods of filter design and


24

Filter implementation in
CD
-
playback system

25

Nonlinear Signal
Processing


For some signal processing systems, nonlinearity is an
essential component: classical examples for nonlinear
systems are quantizers and pattern classifiers.


For nonlinear dynamical systems (such as oscillators,
filters etc.), the conventional approach to their
analysis and design has been linearization as seen e.g.
in the field of adaptive filtering.

26

Nonlinear Signal Processing


Modulation/Demodulation


Adaptive and median filters


Image Encoding and Compression


Video Encoding and Compression


Error proof coding

27

28

TMS32LF2407 appl card


For digital
spectrum

28

29

Next series


C2000, C3000, C4000, C5000, C6000


TMS320 C2000 series consists of 2 families: C240x, an older
16
-
bit line that is no longer recommended for new development
and the C28xx 32
-
bit line.


The newer C28xx family consists of a Delfino high
-
performance
floating point line and a low
-
cost Piccolo line. The C2000 series
is notable for its high performance set of on
-
chip control
peripherals including
PWM
,

ADC
,

quadrature encoder

modules,
and capture modules. The series also contains support
for

I2C
,

SPI
, serial (SCI),

CAN
,

watchdog
,

McBSP
, external
memory interface and GPIO.


30

F2800 seria cores progress

30

31

Application of

DSP in
sound system for car

32

Video
-
pipe