Digital Signal Digital Signal ProcessorProcessor

Digital Signal Digital Signal ProcessorProcessorOverviewOverviewOverviewOverview

2

Signal ProcessingSignal Processing

SpecializedSpecializedADC

2D

01101110001010110100010110111000101011010001

10111010010001010100111101110100100010101001110101010111000101010011101010101110001010100111

ADCADC

1D

Real-time?Real-time?

3

Real-time tasks

Real-timeReal-time Processing Processing

Example: Example: 100-tap FIR filter100-tap FIR filter è è eseguito real-time se si è in grado di eseguito real-time se si è in grado di completare l’operazione di filtraggio completare l’operazione di filtraggio entro due istanti di capionamento entro due istanti di capionamento successivi:successivi:

99

0k

knxkany

La definizione di Real-time Processing dipende dal contesto applicativo

Processing Time Waiting Time

Sample TimeSample Timenn n+1n+1

WTPT

ST

WT WT 0 0

4

Analog Signal ProcessingAnalog Signal Processing

Specialized Specialized HWHW

1D

ASICASIC

2D

5

Le tolleranzetolleranze associate a questi componenti analogici, la temperaturatemperatura, le variazioni variazioni di voltaggiodi voltaggio e le vibrazioni meccanichevibrazioni meccaniche possono drammaticamente indurre effetti

non prevedibili sul circuito analogico.

Le tecniche di processing analogico si avvalgono di componenti come: ResistorsResistors, , CapacitorsCapacitors e e InductorsInductors.

Analog Signal ProcessingAnalog Signal Processing

6

ADC

2D

01101110001010110100010110111000101011010001

10111010010001010100111101110100100010101001110101010111000101010011101010101110001010100111

Digital Signal ProcessingDigital Signal Processing

Specialized Specialized CPUCPU

ADCADC

Specialized Specialized HWHW

DSPDSP

FPGAFPGA

LW R1, a(R4R4)LW R2, b(R4R4)ADD R3,R1,R2SW c(R4R4),R3

ASICASIC

1D

7

FIR Filter with Linear PhaseFIR Filter with Linear Phase

Le attuali tecniche di processing digitale sono così potenti che in particolari ambiti

applicativi, è quasi impossibile, per le tecniche di processing analogiche ottenere

performance comparabili.

Adaptive FiltersAdaptive Filters

Digital Signal ProcessingDigital Signal ProcessingFIR FilterFIR Filter

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Digital Signal ProcessingDigital Signal Processing

Change Change applicationsapplications

Correct Correct applicationsapplications

Update Update applicationsapplications

Easy

Reduces

Noise susceptibilityNoise susceptibilityDevelopment timeDevelopment time

Power consumptionPower consumption

Cost

ProgrammaProgrammable ble

HardwareHardware

DSPDSPFPGAFPGA

ProgrammabilitàProgrammabilità

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High frequency signalsHigh frequency signals cannot be processed digitally because of two reasons:

Digital Signal ProcessingDigital Signal ProcessingLimiti degli ADCLimiti degli ADC

Le applicazioni diventano troppo Le applicazioni diventano troppo complesse per essere elaborate in complesse per essere elaborate in

Real-timeReal-time

Analog to Digital Converters (ADC Analog to Digital Converters (ADC ) non lavorano ad alte frequenze) non lavorano ad alte frequenze

ADC

10

Digital Signal ProcessorDigital Signal ProcessorDSP vs. GPPDSP vs. GPP

General Purpose Processor General Purpose Processor (GPP)(GPP)Large memoryLarge memory

Advanced operating Advanced operating systemssystems

Processing of many “high” Processing of many “high” frequency signals in real-timefrequency signals in real-time

Cost savingCost saving Smaller sizeSmaller size

Low power consumptionLow power consumption

Digital Signal Processor Digital Signal Processor (DSP)(DSP)

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Algorithm Equation

Finite Impulse Response Filter

M

kk knxany

0

)()(

Infinite Impulse Response Filter

N

kk

M

kk knybknxany

10

)()()(

Convolution

N

k

knhkxny0

)()()(

Discrete Fourier Transform

1

0

])/2(exp[)()(N

n

nkNjnxkX

Discrete Cosine Transform

1

0

122

cos).().(N

x

xuN

xfucuF

La Somma di Prodotti (SOPSOP) è la base di molti algoritmi tipici per DSP:

Digital Signal ProcessorDigital Signal ProcessorAlgoritmo SOPAlgoritmo SOP

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I processori DSP sono ottimizzati per operazioni di somma e moltiplicazione. Moltiplicazioni

e addizioni sono eseguite con hardware specializzati e completate in un ciclo di clock.

HardwaHardwarere

MicrocoMicrocodede

10111011x 1110x 1110

1001101010011010

10111011x 1110x 1110

000000001011.1011.1011..1011..1011...1011...

1001101010011010

Cycle 1Cycle 1Cycle 2Cycle 2Cycle 3Cycle 3Cycle 4Cycle 4

Cycle 5Cycle 5

Digital Signal ProcessorDigital Signal ProcessorHardware vs. MicrocodeHardware vs. Microcode

Example: Example: 4-bit multiply4-bit multiply

(unsigned)(unsigned)

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Parameter

Arithmetic format

Extended floating point

Extended Arithmetic

Performance (peak)

Number of hardware multipliers

Number of registers

Internal L1 program memory cache

Internal L1 data memory cache

Internal L2 cache

32-bit

N/A

40-bit

1200MIPS

2 (16 x 16-bit) with 32-bit result

32

32K

32K

512K

32-bit

64-bit

40-bit

1200MFLOPS

2 (32 x 32-bit) with 32 or 64-bit result

32

32K

32K

512K

TMS320C6211 (@150MHz)

TMS320C6711 (@150MHz)

C6711 Datasheet: C6711 Datasheet: TMS320C6711.pdf

C6211 Datasheet: C6211 Datasheet: TMS320C6211.pdf

Digital Signal ProcessorDigital Signal ProcessorParametri TecniciParametri Tecnici

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Parameter

I/O bandwidth: Serial Ports (number/speed)

DMA channels

Multiprocessor support

Supply voltage

Power management

On-chip timers (number/width)

Cost

Package

External memory interface controller

JTAG

2 x 75Mbps

16

Not inherent

3.3V I/O, 1.8V Core

Yes

2 x 32-bit

US$ 21.54

256 Pin BGA

Yes

Yes

2 x 75Mbps

16

Not inherent

3.3V I/O, 1.8V Core

Yes

2 x 32-bit

US$ 21.54

256 Pin BGA

Yes

Yes

TMS320C6211 (@150MHz)

TMS320C6711 (@150MHz)

Digital Signal ProcessorDigital Signal ProcessorParametri TecniciParametri Tecnici

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Can be slower than fixed-point Can be slower than fixed-point counterparts and larger in sizecounterparts and larger in size

Digital Signal ProcessorDigital Signal ProcessorFixed vs. FloatingFixed vs. Floating

FloatingPoint

Ease of Ease of useuse

High High precisionprecisionWide dynamic rangeWide dynamic range

High signal-to-noise ratioHigh signal-to-noise ratio

Higher power Higher power consumptionconsumption

Can be more expensiveCan be more expensive

It is the application that dictates which It is the application that dictates which device and platform to use in order to device and platform to use in order to achieve optimum performance at a low achieve optimum performance at a low

cost cost

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AdvantagesAdvantages

• High throughputHigh throughput• Lower silicon areaLower silicon area• Lower power consumptionLower power consumption• Improved reliabilityImproved reliability• Reduction in system noiseReduction in system noise• Low overall system costLow overall system cost

DisadvantagesDisadvantages

• High investment costHigh investment cost• Less flexibilityLess flexibility• Long time from design to Long time from design to

marketmarket

Digital Signal ProcessorDigital Signal ProcessorGP-DSP vs. ASIC-DSPGP-DSP vs. ASIC-DSP

Application Specific Integrated Circuits Application Specific Integrated Circuits (ASICs) are semiconductors designed (ASICs) are semiconductors designed

for dedicated functionsfor dedicated functions

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VoIP

Digital Signal ProcessorDigital Signal ProcessorTexas Instruments’Texas Instruments’ TMS220 FamilyTMS220 Family

C2000

C5000

C6000

Lowest CostLowest CostControl SystemsControl Systems- Motor Control- Motor Control- Storage- Storage- Digital Ctrl - Digital Ctrl

SystemsSystems

EfficiencyEfficiency Best MIPS per Watt / Best MIPS per Watt /

Dollar / SizeDollar / Size

- Wireless phones- Wireless phones- Internet audio - Internet audio

playersplayers- Digital still cameras - Digital still cameras - Modems- Modems- Telephony- Telephony- VoIP- VoIP

Performance &Performance &Best Ease-of-UseBest Ease-of-Use

- Multi Channel and - Multi Channel and Multi Multi

Function App'sFunction App's- Comm Infrastructure- Comm Infrastructure- Wireless Base-- Wireless Base-

stationsstations- DSL- DSL- Imaging- Imaging- Multi-media Servers- Multi-media Servers- Video- Video

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TMS320TMS320CC64x:64x: The C64x fixed-point DSPs offer the industry's highest level of performance to address the demands of the digital age. At clock rates of up to 1 GHz, C64x DSPs can process information at rates up to 8000 MIPS with costs as low as $19.95. In addition to a high clock rate, C64x DSPs can do more work each cycle with built-in extensions. These extensions include new instructions to accelerate performance in key application areas such as digital communications infrastructure and video and image processing.

TMS320CTMS320C6262x:x: These first-generation fixed-point DSPs represent breakthrough technology that enables new equipments and energizes existing implementations for multi-channel, multi-function applications, such as wireless base stations, remote access servers (RAS), digital subscriber loop (xDSL) systems, personalized home security systems, advanced imaging/biometrics, industrial scanners, precision instrumentation and multi-channel telephony systems.

TMS320CTMS320C6767x:x: For designers of high-precision applications, C67x floating-point DSPs offer the speed, precision, power savings and dynamic range to meet a wide variety of design needs. These dynamic DSPs are the ideal solution for demanding applications like audio, medical imaging, instrumentation and automotive.

Digital Signal ProcessorDigital Signal ProcessorTMS220 - C6000TMS220 - C6000