MOBAT MICOMMOBAT – MICOMThe best radio for worst events

Increasing Data ThroughputIncreasing Data Throughput Over HF links

Hana Rafi - General Manager

Eder Yehuda - VP R&D

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Traditional HF RadioTraditional HF Radio

- Analog voice & 50,75…bpsg , p

New Trends on HF

- Digital voice, Noise reduction…

- High Data Rate …19200…bpsQAM

High linearity, SNR ,Efficiency

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Requirements from the New HF RadioRequirements from the New HF RadioFor HDR performance

-Linearity - ISI

High dyn range

-High efficiency

Small size-High dyn. range

-Low ACI & IBN

-Small size.

-High MTBFLow ACI & IBN

-High Power TX.

High MTBF.

-feasible.

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HPA andHPA andHigh Data Rate (HDR)

TX Inter-Mod : 31dBHDR RX SNR Requirements : >33 dBq

PSD

31dBSNR

~30dB

Frequency

4

q y

micom Radiomicom Radio &HPA Solution

Linearized Power Amplifier :ii C t Smicommicom Current Spec.

TX PWR 125/175W… 125W Availability !Inter-Mod >42 dB 30-32dB Data Rate !Efficiency >45% 30% Energy !Efficiency 45% 30% Energy !PWR con. 280 /390W 416W Size !

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micommicom HDR-ISB coco SSystem Solution

micom – 2*ISB Radio 125/175W

d f 500 4000 Wready for 500-4000 W

micom MD 9600/19200micom – MD-9600/19200

STD-5066 email gateway g yJITC @ Q1-Q2 2005

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Technical session onLinearized techniques & Achievements on

micom – radiomicom radio

Mr Yehuda EderMr. Yehuda Eder

Thank you , have a productive day

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Problem descriptionob e desc p o

LinearPout

Non Linearity caused by:

• PA/transmitter linearization

PinPSD

• RGC – Receiver Gain Control• TGC/ALC – Transmitter Gain Control• D/A-A/D – Resolutions

L l O ill h i

ACIBBN

• Local Oscillators phase noise • Receiver/Transmitter BW• Group Delay Variation

Freq

BBN

ISIIBN

8

Freq.

Available SolutionsAvailable Solutions

Linear Power Transceiver :Linear Power Transceiver :

Linear Power Amplifier, Class-A or A/B with large backoff :Low efficiency high costLow efficiency, high cost

AGC, TGC,ALC : HELD (Input regulation based on average signal level should be held) )HF channel receive signal variations may cause problems to the receiver performance and the linearity.

Linearized Power Amplifier High Efficiency and IMD

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RGC – Receiver Gain ControlTGC/ALC Transmitter Gain ControlTGC/ALC–Transmitter Gain Control

Special techniques for attack-release of p qGAIN CONTROL must be used.

GAIN

T > delta between 2 peaks

Data AGC

GAIN

Typical AGC

TIME

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A/D –D/A Quantizing NoiseA/D D/A Quantizing Noise

Distortion & Noise in CODECs•Integral non-linearity•Differential non-linearity.•Total Harmonic Distortion (THD)Total Harmonic Distortion (THD).•Total Harmonic Distortion Plus Noise (THD+N)•Signal to Noise and Distortion Ratio (SINAD, or S/N+D).•Effective Number Of Bits (ENOB).( )•Signal to Noise Ratio (SNR).•Analog Bandwidth (Full Power, Small Signal)•Spurious Free Dynamic Range (SFDR).•Two Tone Inter-modulation Distortion.•Noise Power Ratio (NPR).

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Local/Synthesizer Oscillators phase noisey p

The synthesizer is the source of:yIBNBBN

Hi h iHigh noise near the carrier =

SNR degradation

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Receiver/Transmitter BW

In band ripple

Group delay variances

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PA characteristics - linear scalePA characteristics linear scale

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“Typical” class AB PA characteristicsTypical class AB PA characteristics (measurements)

Power Gain Phase Transfer FunctionPower Gain Phase Transfer Function

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PA linearity vs SNRPA linearity vs. SNR

MIL-STD188-141B Requirement: Intermodulation distortion (IMD).Intermodulation distortion (IMD).The IMD products of HF transmitters produced by any two equal-level signals within the 3 dB bandwidth shall be at least 30 dB below either tone for fixed station application, and 24 dB below either tone for tactical application.

The 24/30dB limits the SNR performance.

Summary Performance tests results: SNR IMD (below tone)

3445

3339

3133

2830

2424 2424

1920

1819

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the IMD should be improved for better SNR

PA Linearization TechniquesPA Linearization Techniques

Power Amplifier Linearization Techniques:p q• Feed Forward • Pre-Distortion • EER – Envelope Elimination RestorationEER Envelope Elimination Restoration • Cartesian Feedback

O hOur approach: High Efficiency Class-AB amplifier with Cartesian Feedback & EER to achieve high linearity and high efficiency.

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Linearization TechniquesFeed-forward

Linearization Techniques

Vi VoP. A.G1 1 21 1 2

Error

1G2 2

Amplifier

High complexity, Wide BW @ low freq. Range

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pre-distortionLinearization Techniquespre-distortion

Vo

F(*)linear

Vi

VoP. A.Vi iV

Predistorter

iV

Vm

F(Vm)

Vi Vm

High complexity, Wide BW @ low freq. Range

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Digital adaptive pre-distortionLinearization Technique

Digital adaptive pre distortion

V oF (V m )

P . A .

D / A D / A

I \ QM o d .

L . O .

P o la r to C a r te s ia n

D / A D / A

Var. A

t

P re -d is to r tio nc a lc u la tio n

P h i(k T s)

I(k T s ) Q (k T s )P re d is to r te dA d a p tiv e

P re d is to r t io n

tt.

Adress

D a t a

L o o k -u p ta b leC a r te s ianto P o la r

I /Q (k T s )

A m p (k T )

A d a p ta tio n a lg o rith m

(A i,P h ii) n e w(A i,P h i i) o ld

\T a b le s

A m p (k T s)

I \ QD e m o d .

A / D

D o w nC o n v e r te r

I/Q (k T s )D e m o d u ta te d

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D ig ita l e le m e n tsR F / a n a lo g e le m e n ts

EER (Envelope Elimination and Restoration)

Envelopemodulator

VDD

)(cos)( tttVtV ci VoP. A.Signal

separation

)(1 tVtS

)(cos2 tttS c

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PA without AM-to-PM –AM loopIpol=[-95 0 87 0] ; Qpol=0

PA Ch t i ti T T I t d l ti AM l

10

15

20

Gai

n

PA Characteristics

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40Two Tone Intermodulation. - AM loop

green - Sourceblue - PAred - PA with linearizer

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.80

5

Vin [Volt]

200

-20

0

Am

p [d

B]

-100

0

100

200

Pha

se [o ]

-60

-40

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8-200

100

Vin [Volt]

200 210 220 230 240 250 260 270 280 290 300-80

IM3 = 25 dBcAM loop improvement > 20 dB

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AM loop improvement > 20 dB

PA with AM-to-PM ( 0 ÷ 25° ) – AM loopIpol=[-95 0 87 0] ; Qpol=[-75 0 0 0]

10

15

20

Gai

n

PA Characteristics

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40Two Tone Intermodulation. - AM loop

green - Sourceblue - PAred - PA with linearizer

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.80

5

Vin [Volt]

G

180-20

0

mp

[dB

]

160

170

180

Pha

se [o ]

-60

-40A

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8150

Vin [Volt] 200 210 220 230 240 250 260 270 280 290 300-80

IM3 = 25 dBcAM loop improvement =0 dB

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For QAM modulation EER is not efficient

Micom Linearization solution EER & Cartesian loopEER & Cartesian loop

DCP.S.

LPF

Envelope

LPF28 / 48 VDC

110 VAC (option)

PIN =1 WattSignal Processing

Unit

P A

Harmonicfilter

PTX =500 Watt

Phase modulated RF

RF modulated-to-Polar

Cartesian Linearization(complex closed loop)

Unit

DC feedback

Att.

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Micom simulation results

40Two Tone Intermodulation. - Complex loop

Micom simulation results

0

20

green - Sourceblue - PAred - PA with linearizer

-40

-20

Am

p [d

B]

200 210 220 230 240 250 260 270 280 290 300-80

-60

200 210 220 230 240 250 260 270 280 290 300

IM3 = 20 dBcComplex loop improvement ~ 25 dB

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Two complex tones - baseband spectrumTwo complex tones baseband spectrumf1 = -30 Hz, f2 = 25 Hz

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Two complex tones - I/Q plotp Q p)2sin()2sin()( 21 tfatfatI

)2/2sin()2/2sin()( 21 tfatfatQ

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Single tone (modulating signal) I/Q plotSingle tone (modulating signal) I/Q plot

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Non-Linear PA

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Linearized PALinearized PA

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Single tone time waveforms (RF or modulating signal)

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I/Q plotQ p

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Thank you

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