Earth Station Equipment · • Co-axial cable Combiners / Splitters • Waveguide. 6 Uplink Block Diagram • Modulator / Modem • Up-Converter • Power Amplifier • Antenna

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Earth Station Equipment

Cyril Sayegh

Customer Solutions Engineer

ITSO Cairo

Sept 2014

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RF Chain diagram

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Uplink and Downlink path

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Flexible Waveguide OMT Feed

RX output,horizontal

LNB

Outdoor units

TRF

TX input,vertical

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Uplink Block Diagram• Modulator / Modem

• Up-Converter

• Power Amplifier

• Antenna

• Inter Facility Link (IFL)

• Fiber Optics

• Co-axial cable Combiners / Splitters

• Waveguide

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• Up-Converter

• Power Amplifier

• Antenna


• Fiber Optics


• Waveguide

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Modems - Selection• SCPC

• Low Throughput 64Kbps

• High Throughput >300Mbps

• Carrier Cancellation

• TDM/TDMA

• Simple Hubless solution

• Star Network

• Mesh network

• Advanced features

• Roll Off

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Modem Interfaces

• RS232/RS422

• HSSI/G703/Ethernet

• D-Type connector, BNC, Ethernet

• IDR G703 E1/T1

• IBS: RS422/RS232/ITU.V35

• ASI

• Ethernet

• SDI

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Common Modulation TechniquesA sinusoid has 3 different parameters that can be varied. These are amplitude,

phase and frequency.

The three basic types of digital modulation are :

• Amplitude Shift Keying (ASK)

• Frequency Shift Keying (FSK)

• Phase Shift Keying (PSK)

Some Old analog modulations: AM, FM..

Popular modulation types used for satellite communications:

(BPSK) Binary; (QPSK) Quadrature; 8PSK; (QAM)especially 16QAM

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Amplitude Modulation (AM)

Vary the Amplitude

In AM modulation, the voltage (amplitude) of the carrier is varied by the incoming signal. In this example, the modulating wave implies an analog signal.

AM is also used for digital data. In quadrature amplitude modulation (QAM), both amplitude and phase modulation are used to create different binary states for transmission.

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Digital 8QAM

In this 8QAM example, three bits of input generate eight different modulation states (0-7) using four phase angles on 90 degree boundaries and two amplitudes: one at 50% modulation; the other at 100% (4 phases X 2 amplitudes = 8 modulation states). QAM examples with more modulation states become extremely difficult to visualize.

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Digital Amplitude Shift Keying (ASK)

For digital signals, amplitude shift keying (ASK) uses two voltage levels for 0 and 1 as in this example.

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Frequency Shift Keying (FSK)

FSK is a simple technique that uses two frequencies to represent 0 and 1.

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Phase Shift Keying (PSK)

For digital signals, phase shift keying (PSK) uses two phases for 0 and 1 as in this example.

PSK offers excellent performance and makes multi-phase modulation available. PSK is the method most commonly used in digital satellite communication systems.

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Quadrature Phase Shift Keying (QPSK)

QPSK uses four phase angles to represent each two bits of input; however, the amplitude remains constant.

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Phase Shift Key

• QPSK – 2 bits per symbol

• 8PSK – 3 bits per symbol

• 16APSK – 4 bits per symbol

• 32APSK – 5 bits per symbol

• etc

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• Up-Converter

• Power Amplifier

• Antenna


• Fiber Optics

• Co-axial cableCombiners / Splitters

• Waveguide

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Up-Converter (U/C)

•The method used to achieve the conversion is heterodyning. That is the mixing of two different frequencies into a non-linear device ( mixer ) to produce two other frequencies equal to the sum or difference of the first two, while maintaining it’s characteristics

� A device that converts an input signal known as the intermediate frequency (IF) to a desired higher frequency without disturbing the intelligence (modulation) on the incoming signal

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Up-Converter (U/C)

• 140 MHz to L-Band

• 140 ±72 MHz input

• 950 – 1450 MHz output

• Non inverting

• 72 MHz bandwidth

� 70 / 140 MHz IF to L-Band

– 70 MHz to L-Band• 70 ±18 MHz input

• 950 – 1450 MHz output

• Non inverting


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Up-Converter (U/C)

•L-Band to C-Band• 950 - 1450 MHz input

• 5.925 – 6.425 GHz output

• Non inverting (4.900 GHz LO)

• Inverting (7.375 GHz LO)


� L-Band to Ku-Band– 950 - 1450 MHz input

– 14.00 – 14.50 GHz output

– Non inverting (LO = 13.050 GHz)

– Inverting (LO = 15.450 GHz)

– 500 MHz bandwidth

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Up-Converter (U/C)

•70 MHz to C-Band• 70 ±18 MHz input

• 5.850 – 6.425 GHz output

• Non inverting


• 140 MHz to C-Band• 140 ± 36 MHz input

• 5.850 – 6.425 GHz output

• Non inverting


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Up-Converter (U/C)

•70 MHz to Ku-Band• 70 ±18 MHz input

• 14.00 – 14.50 GHz output

• Non inverting


� 140 MHz to Ku-Band– 140 ± 36 MHz input– 14.00 – 14.50 GHz output– Non inverting– 72 MHz bandwidth

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• Up-Converter

• Power Amplifier

• Antenna


• Fiber Optics

• Co-axial cableCombiners / Splitters

• Waveguide

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Power Amplifiers

• High Power Amplifiers - HPA

• Solid State Power Amplifiers - SSPA

• Travelling Wave Tube – TWT

• Klystron Power Amplifier KPA

• Including/excluding Up-conversion

• Transceivers

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Transceiver• Combination Power Supply, Up / down converter, HPA and

LNA - PSU

• Mounted on / at the antenna

• 70 or 140 MHz or L-Band input

• RF Output C/Ku/Ka-Band output

• Single or dual synthesized converters

• Uplink

• Downlink

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Solid State Power Amplifiers• Typical output power 5 to 200 Watts


• Non Linear

• L-Band Up-Converter optional

• Requires external 10 MHz reference

• Requires Diplexer

• Typically ≈ 3 dB OBO for multi carrier operation

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Solid State Power Amplifiers

• Lower Power 1- 200W

• Lower OBO for multicarrier operation

• Cost effective

• Low maintenance

• Power efficient

• Susceptible to power and lightning damage

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Travelling Tube Amplifier– Typical output power 100 – 750 Watts

– 500MHz - 750 MHz bandwidth

– Non Linear

– Built in BUC optional

• Requires 10 MHz external reference and Diplexer

– ≈ 7 dB OBO for multi carrier operation

– ≈ 4 dB OBO with linearizer for multi carrier operation

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Transmitters (HPA)

• HPA HIGH POWER AMPLIFIER

• TRAVELING WAVE TUBE AMPLIFIER

• WIDEBAND ( FULL SPECTRUM ) GREATER 500MHz

• NON LINEAR

• SMALL SIGNAL SUPRESSION

• AMPLITUDE TRANSFER CURVE

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Travelling Wave Tube Amplifiers

• Medium Power 200W – 750W

• Phase combined

• Also available in higher power

• Wideband >500MHz

• 4dB to 7dB OBO multicarrier operation

• Dependent on linearizers fitted

• Medium maintenance

• Medium robustness to lightning damage and

reflections

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Transmitters (HPA)

• SMALL SIGNAL SUPRESSION

• AMPLITUDE TRANSFER CURVE

• INTERMODULATIONf 1 - f 2 f 1 + f 2f1 f2

( f 1 - f 2 ) - f 1

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Klystron Power Amplifier

– Typical output power 1000 to 3000 Watts– Non linear– 40 or 80 MHz bandwidth– OBO ≈ 2 dB for dual carrier operation

≈ 7 dB for multi carrier operation

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Transmitters

KLYSTRON POWER AMPLIFIER

NARROWBAND TUNED CAVITY FREQUENCY RESPONSE

GROUP DELAY

HIGH POWER

NON-LINEAR

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Klystron Power Amplifiers

• High Power 1000 – 30000W

• Narrowband approx. 80MHz

• 7dB OBO - multicarrier operation

• High maintenance and high operations costs

• High level skills and equipment needed to

operate - tuning

• High to lightning damage and reflections

• Power hungry

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• Up-Converter

• Power Amplifier

• Antenna


• Fiber Optics


• Waveguide

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Inter Facility Linking

• Co-axial cabling

• Data and base band

• IF

• L-Band

• C-Band

• Ku-band

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RF Co-axial Cabling

• Important factors

• Higher Frequency higher losses

• Losses indirectly proportional to cable diameter

• Skin effect

• To a point

• Losses directly proportional to frequency

• Reflections – impedance mismatch

• Cable damage

• Water

• System impedance

• Connector

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Waveguide

• Used at C-Band and higher frequencies

• Lower loss than co-axial cable

• Types:

• Rigid

• Flexible, Flexible and twistable

• Elyptical

• Not wideband – Frequency determines

dimension

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Combiners Small Signal

• Types

• IF

• L-band

• C-Band/Ku-band

• Considerations

• Losses

• Impedance matching

• Terminating unused ports

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Combiner - Wideband

• 3dB Coupler

• Co-axial

• Waveguide

• High power

• Wideband

• 3dB loss Dummy load required

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Combiner - Filter

• Co-axial

• Waveguide

• Variances

• One port wideband

• Other port narrowband

• Low insertion losses

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Patch Panels

8:1

IF Patch Panel

Modem

Modem

Modem

Modem

DATAPatch Panel

1:8

Up-Converter

Down-Converter

1:2HPA

1:2 LNA

10 dB

Coupler40 dB

Coupler

50 dB

Inject

Coupler

IF Patch Panel

TP-1 TP-2

TP-3TP-4

Uplink & Downlink Patch Panel and RF monitor block diagram

– 10 dB coupler on Up-Converter output (TP-1)

• Monitor Up-converter output

– 40 dB coupler at feed input (TP-2)

• Monitor aggregate transmit carriers and power

– Receive inject coupler (TP-3)

• Capability to inject carrier prior to LNA

– Ability to calibrate downlink chain

- Splitter at Down-Converter input (TP-4)

- Monitor full 500 MHz downlink spectrum

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Downlink Components

• Demodulator / Modem

• Down-Converter

• LNA

• Antenna


• Fiber Optics

• Co-axial cable

• Patch Panels

• Combiners / Splitters

• Waveguide

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Low Noise Amplifier (LNA)

• Lower the Noise Temperature, the better the performance

� Input Waveguide– CPR-229 C-Band– WR-75 Ku-Band

� Output Coaxial connector– N-Type (50 ohm) Standard C-Band– SMA (50 ohm) Standard Ku-Band

� Typical 3 stage amplification (Designed to keep noise down)– No Frequency Conversion

� “Noise Temperature” is the amount of noise added – Specified in degrees K for C-Band

• 20o – 40oK Typical

– Specified as Noise Figure (NF) for Ku-Band

• 0.7 to 1.0 Typical (50o – 75oK)

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Low Noise Block Down-Converter (LNB)

•Output Coaxial connector• N-Type (50 ohm)

• F-Type (75 ohm)

Low Noise Amplifier

DC Regulator

Input Output

Power

� LNA with a Block Down-Converter built in� Provides Frequency Conversion

– DRO (Dielectric resonator Oscillator) • ± 150 kHz to ± 500 kHz C-Band• ± 150 kHz to ± 900 kHz Ku-Band

– PLL (Phase Locked Loop)• ± 5 kHz to ± 25 kHz C-Band• ± 5 kHz to ± 50 kHz Ku-Band

– External (10 MHz reference)

� Input Waveguide

– CPR-229 C-Band

– WR-75 Ku-Band

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PLL vs DROPLL stands for Phased Locked Loop

DRO is Dielectric Resonator Oscillator

PLLs are more stable than DROs, as they use a more stable internal reference source (crystal oscillators) or an input from a stable external source (rubidium clock, analog 10MHz signal source, etc)

For low bitrates or small carriers DRO provides a better solution.

DROs are OK to receive large bitrate carriers (such as DVB multiplexes for instance).

Advantages of DROs are price as it is very cheap.

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Low Noise Amplifier (LNA/LNB)

• Frequency stability of LNB critical depending on type of service

� Designed to provide the lowest noise contribution as possible– 20o – 40o K noise temperature typical for C-band

– 70o – 90o K noise temperature typical for Ku-band

– 50 to 60 dB Gain typical

� Mounted as close as possible to the OMT waveguide ports

� One of the most critical components of an antenna system– Major factor in determining the systems figure of merit (G/T)

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Down-Converter (D/C)

•A device that converts an RF input signal to a desired lower frequency known as the intermediate frequency (IF) without disturbing the intelligence (modulation) on the incoming signal

•The method used to achieve the conversion is heterodyning. That is the mixing of two different frequencies into a non-linear device ( mixer ) to produce two other frequencies equal to the sum or difference of the first two, while maintaining it’s characteristics

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D/C Frequency Calculations

• Modem IF Frequency = 1270.5 MHz (5150 – 3879.5)

• LNB LO freq (-) Downlink freq

� C-band to L-Band– Inverted C-Band (LNB)

– LO frequency of the LNB (5150 MHz)

– Carrier Downlink Frequency 3879.5 MHz

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• Carrier Downlink Frequency 11907.5 MHz


� Ku-Band to L-Band– Non Inverted Ku-Band (LNB)– LO frequency of the LNB (10750 MHz)

– Modem IF Frequency = 1157.5 MHz (11907.5 – 10750)– Downlink freq (-) LNB LO freq

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• Modem IF Frequency = 65.5 MHz (5150 – 3879.5 -1275 +70)

• LNB LO freq (-) Downlink freq (-) D/C center freq (+) 70 MHz

� Inverted C-Band (LNB)

– Center Frequency of transponder (3875 MHz)

– LO frequency of the LNB (5150 MHz)– Center frequency of Down-Converter = 1275 MHz (5150 – 3875)

– LNB LO freq (-) Bandwidth center freq


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• Modem IF Frequency = 65.5 MHz (11907.5 – 10750 - 1150 +70)

• Downlink freq (-) LNB LO freq (-) D/C center freq (+) 70 MHz

� Non Inverted Ku-Band (LNB)


– LO frequency of the LNB (10750 MHz)– Center frequency of Down-Converter = 1150 MHz (11900 – 10750)

– Bandwidth center freq (-) LNB LO freq


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• Modem IF Frequency = 74.5 MHz (3879.5 – 3875 + 70)

• Downlink freq (-) U/C center freq (+) 70 MHz

� C-Band (70 MHz)– Center Frequency of transponder (3875 MHz)

– Center frequency of Down-Converter = 3875 MHz


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– Modem IF Frequency = 144.5 MHz (3879.5 – 3875 + 140) – Downlink freq (-) U/C center freq (+) 140 MHz

� C-Band (140 MHz)– Center Frequency of transponder (3875 MHz)

– Center frequency of Down-Converter = 3875 MHz


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• Ku-Band (70 MHz)



– Center frequency of Down-Converter 11900 MHz


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• Ku-Band (140 MHz)



– Center frequency of Down-Converter 11900 MHz


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Earth Station Measurements

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Intermodulation Distortion

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Intermodulation Distortion

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Linear/Non Linear Operating Point

It is defined as the output power level at which the actual

gain deviates from the small signal gain by 1 dB

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System Gain

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Transmit Gain

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Best Practices

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TX IFL/RF – Chain Measurement

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TX IFL/RF – Chain Measurement

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Non Linear Effects on Digital Signals

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Thank you !

Questions ?

Documents

Earth Station Equipment · • Co-axial cable Combiners / Splitters • Waveguide. 6 Uplink Block Diagram • Modulator / Modem • Up-Converter • Power Amplifier • Antenna