ISDB-T Transmitter Design and Technology Advances

1
COMMUNICATION TECHNOLOGIES CO. LTD
Anywave Technical Presentation
July 2016 – Focus on OFDM and ISDBT

2
ANYWAVE Agenda
1. A Brief Overview Of ISDB-Tb Standards
2. Transmission System Basics
3. Transmitter Design
4. Advances In Solid State Technology
5. ISDB-T Transmitter Measurements
6. Safety And The Basics Of Transmitter Maintenance
7. OCR and Single Frequency Network (SFN)

3
1. A Brief Overview Of ISDB-T
ANYWAVE
ANYWAVE Presentation

4
HD ENCODER
SD ENCODER
1 SEG ENCODER
REMULTIPLEXER
EXTERNAL GPS
ISDBT TRANSMITTER
HD-SDI ~ 1.5GB/s
SD-SDI ~ 270MB/s
300KB/s
3MB/s
15MB/s
~ 32.5MB/s RF ON CHANNEL
ANYWAVE ISDB-T Overview
SYSTEM CONFIGURATION

5
MPEG-4 VIDEO CODEC
MPEG-4 AAC AUDIO CODEC
AUDIO PACKET
VIDEO
SOUND
VIDEO PACKET
• The Audio and Video signals are
converted to SDI signal
• The SDI is coded and compressed in
MPEG-4 becoming a transport Stream
(TS).
• The TS packet has 188 Bytes made up
of the HEADER and PAYLOAD.
SYSTEM CONFIGURATION

6
SYNC
BYTE
8
TRANSPORT
ERROR
INDICATOR
1
START
INDICATOR
1
TRANSPORT
PRIORITY
1
PID
13
SCRAMBLING
CONTROL
2
ADAPTION
CONTROL
2
CONTINUITY
CONTROL
4
ADAPTION
FIELD
PAYLOAD

7
THE ACRONYMS YOU SHOULD KNOW…
PSI/SI tables are responsible for the transmission of system and service information.
The main SI tables are: PAT, PMT, NIT, TOT and SDT.
• PAT – Program Association Table – Lists the PMT's present in the (TS)
• PMT – Program Map Table – Lists all PID's present in each service
• NIT – Network Information Table – Contains network info (Ex.: Station name, Station Id, etc...)
• TOT – Time Offset Table – Contains information related to time
• SDT – Service Description Table – Describes the services present in the TS

8
• Although the root concepts of QPSK and 4-QAM are different, the
resulting modulated radio waves are exactly the same.
• QPSK uses four points on the constellation diagram, equispaced
around a circle. With four phases, QPSK can encode two bits per
symbol
• Represents four possible states, changing only the signal’s
phase. Very robust against noise (information farther from each
other), but with small transmission capacity.
• Ideal for 1-Seg modulation
• QPSK constellation diagram: each adjacent symbol only differs by one bit
QPSK

9
• QAM is both an analog and a digital modulation scheme; and represents 16 possible states
• It conveys two digital bit streams, by changing (modulating) the amplitudes of two carrier
waves, using the amplitude-shift keying (ASK) digital modulation scheme.
• The two carrier waves are out of phase with each other by 90° and are thus called
quadrature carriers
• The modulated waves are summed, and the resulting waveform is a
combination of both phase-shift keying (PSK) and amplitude-shift
keying (ASK)
• Ideal for SD modulation
16QAM

10
• 64-QAM Modulation Represents 64 possible states
both changing phase and amplitude.
• Low strength signal but capable of high
transmission rates.
• Ideal for HD
64QAM

11
• FEC is the main component to burst noise
immunity
• Guarantees the error correction for
transmitted signals in the reception stage by
simply adding redundancy bits.
• FEC can be adjusted to 1/2, 2/3, 3/4, 5/6 or
7/8.
• These numbers represent how many of the duplicated bits will be used. The higher the
redundancy the higher is the immunity to burst noise, but the lower the transmission rate.
FORWARD ERROR CORRECTION

12
• Guard Interval is responsible for multipath
immunity;
• In analog what used to generate “ghosts”
• The size of this sample can be 1/4, 1/8, 1/16 or
1/32 of the symbol’s time.
• 1/4 – Greater multipath immunity but with less transmission capacity. 25% of the symbol is repeated.
• 1/32 – Less multipath immunity but with greater transmission capacity. Only 3.125% of the he symbol
is repeated.
• The sample size influences the multipath immunity and the effective data transmission rate.
The OFDM symbol has its end part replicated at the beginning.
GUARD INTERVAL

13
MODE
• Defines the number of OFDM carriers that make up the 6 MHz channel.
• It has no influence on the transmission rate; only in multipath immunity (the longer the
symbol the better) and in the Doppler effect in mobile reception (more space between
carriers, or the smaller the symbol, the better).
• Mode 8k proved itself to be adequate for all types of transmission and is normally used in
ISDB-TB transmissions.

14
Multipath interference
(frequency selective) Flat fading or impulse noise
After De-interleaving
2-dimensional random error
Suitable for Viterbi and Reed Solomon error correction
Corrected Output (No errors)
INTERLEAVING

15
HIERARCHICAL MODULATION
Hierarchical Modulation is obtained by changing the modulation and error correction parameters
Modulation type : QPSK, 16QAM, 64 QAM or DQPSK
Error Correction: Coding rate of convolutional code (1/2 – 7/8)

16
HDTV
SDTV
MOBILE

17
SUMMARY
ISDB-T Is a very robust transmission system due to:
• Hierarchical modulation,
• OFDM and
• Variable Guard Interval
• Time and frequency interleaving
Uses of MPEG4 encoding which decreases complexity and cost and offers SD, HDTV
and ONE-SEG (mobile)
Capable of being received by mobile and fixed reception
THE GOOD NEWS.. With ISDB-T … You have the tools to get the job done…
- Good coverage with plenty of options for HD, SD and mobile

18
THANK YOU FOR YOUR ATTENTION
ANYWAVE
ANYWAVE COMMUNICATION TECHNOLOGIES CO. LTD
300 KNIGHTSBRIDGE PARKWAY,
LINCOLNSHIRE, IL 60069-3655, USA

19
ANYWAVE for all your transmission needs

20
ANYWAVE
SEND US AN EMAIL
Frank.massa@Anywavecom.com
Sales_us@Anywavecom.com
CALL US
(+66) 83 618-9333
(+1) 847 415 2258 (Ext. 1)
VISIT OUR WEBSITE
www.anywavecom.com/en
For Product Inquiries, please don’t hesitate to contact us.

21
ANYWAVE Agenda
Anywave BTSI
Presentation July
2016

22
ANYWAVE

23
ANYWAVE Transmission System Basics
A Transmission System design has to consider the following:
• Transmitter Power Output (TPO)
• Transmission Line Efficiency
• Antenna Gain
• Effective Radiating Power (ERP)
• Total System Price

24
Two design methods:
• Fixed TPO
• Objective ERP
With Fixed TPO
1. Select TPO to meet objective ERP
2. Select type of antenna
3. Select transmission line length and size
With Objective ERP
1. Select ERP
2. Select type of antenna
3. Select transmission line length and size

25
Select a transmitter Power
Output:
LPTV Range
20, 100, 200, 400, 500W
MPTV Range
1000, 1500, 2000, 2500W
HPTV
5kW to 20kW in 1kW steps

26
Type in Transmitter Power
Output: 100, 200, 400, 800 ... etc.
Type in Channel (14-70)
Select Meters or Feet
Select Antenna type
Chose Pattern if slot, choose
number of panels and bays if
Panel type.
Select transmission line size, type
and length and if there is an
additional horizontal run
For cost of Operation
Select Hours per Day and
Average Cost of Electricity

27
Results
ERP = 3.595kW
Estimated Transmitter
Consumption = 1.905KW
Estimated Cost of Operation
$1,390 / Year
$116 / Month
Estimated Cost of Equipment
Purchase
$37,900

28
Type in ERP Objective
(5W – 1MW)
Type in Channel (14-70)
Select Meters or Feet
Select Antenna type
Chose Pattern if slot, choose
number of panels and bays if
Panel type.
Select transmission line size, type
and length and if there is an
additional horizontal run
For cost of Operation
Select Hours per Day and
Average Cost of Electricity

29
Results
TPO = 1.1595kW
Estimated Transmitter
Consumption = 3.408KW
Estimated Cost of Operation
$2,985 / Year
$249 / Month
Estimated Cost of Equipment
Purchase
$92,246

30
1650 3" SLOT $60,000
1750 2 1/4" SLOT $57,000
Selecting the right combination of Antenna type, Line size and TPO can realize
significant savings.. In this case over $15,000.
TPO LINE SIZE ANT. TYPE PRICE
1650 3" SLOT $60,000
800 3" Panel $50,000
2100 1 5/8" SLOT $54,000
650 4" Panel $52,000
800 3" Panel $50,000
OBJECTIVE TO DELIVER 7KW ERP
1000 1 5/8" Panel $45,000

31
ANYWAVE

32

33
ANYWAVE
SEND US AN EMAIL
CALL US
(+66) 83 618-9333
(+1) 847 415 2258 (Ext. 1)
VISIT OUR WEBSITE

34
ANYWAVE Agenda
Anywave BTS
Presentation July
2016

35
ANYWAVE

36
Criteria of developing a new Transmitter
• Its all about the MONEY!
From a manufacturers point of view
• Lower manufacturing costs by using more effective and efficient methods, technology designs
and materials.
• Include new features, benefits and concepts in order to be better than the rest
From the customers point of view
• Lower capital costs
• Lower Operational costs ; Efficiency, Maintenance, Spares and Repairs
ANYWAVE Transmitter Design

37
So how do we meet all these criterion?
• It’s all in the DESIGN
• If you make a transmitter reliable, you lower operating costs for the user and decrease
support costs for the manufacturer.
• Reliability is about oversizing the materials, not cutting corners in materials and providing the
appropriate protection for all scenarios

38
Carved ALUMINUM HEAT SINK
• Single Piece of Aluminum
• All BLF888 devices and reject loads
are directly mounted onto heat sink for
maximum heat dissipation and
minimum heat transfer resistance
• Power cables are routed under the
main board and within the carved heat
sink.
AMPLIFIER DESIGN

39
Carved ALUMINUM HEAT SINK
• High density, heavy duty
• Light weight
• Special fin structure provides large
equivalent surface area
• High density fin panels create air flow
“turbulence” for very fast heat removal
• RESULT: VERY COOL OPERATING
TEMPERATURE OF ENTIRE
AMPLIFIER
AMPLIFIER DESIGN

40
AMPLIFIER DESIGN
COOLING
• Brushless, speed control fans
• 267 CFM rating for each fan
(operates at <100CFM)
• Fan speeds displayed on control unit
and via Web browser remote control
• Temperature controlled for optimum
efficiency and extended life
• Easily field replaceable with two
screws and plug in connectors
• RESULT: Amplifiers operate very
quietly and reliably

41
AMPLIFIER DESIGN RF OUTPUT
• Heavy duty 7-16 DIN output
connector
• Connector rated at 1kW capable
handling power
(45% over-rating)
• No tools required to connect or
disconnect

42
Power Supply
• HOT PLUGGABLE – FROM
FRONT OF TRANSMITTER
• No tools required to remove power
supply
• Heavy power capacity 4000W
AC/DC power supplies
• Total 4000W capacity for 500W
ISDBT output
• Fire and smoke resistant wiring
AMPLIFIER DESIGN

43
• Well shielded multiple compartment
design
• All-digital bias and measurement
adjustment
• Dedicated micro controller in each
PA module for local monitoring
• Real time and continuous
measurements on current, voltage,
bias on each BLF888 device
temperature, forward power and
reflected power levels
AMPLIFIER DESIGN

44
• Comprehensive Graphical
user interface for remote
access
• Complete control and ALL
information available
REMOTE CONTROL AND MONITORING

45
• Complete monitoring and
control functions
• Large 5” touch screen
• 30W output power level
• System Status displayed
• Forward power
• Reflected power
• Rejection power levels
• Optional dBm, Wattage or
percentage display
• VSWR
Driver Status display
• Input level
• Exciter presence and selection
• Forward power reflected power, current, voltage.
• Real time log
• Amplifier mode status displayed
• Forward power, reflected power current, voltage, temperature bias voltage
• Fans Speed
• Remote accessibility: (1) RS232, (2) RS485, (1) RJ45, Web interface
(Available on transmitters above 400W).
CONTROL AND
MONITORING

46
• Transport Stream
Processing
• Modulation
• Automatic Digital
Pre-correction
• Digital to Analog
Conversion
• Amplification –
• -25 – 5dBmb
Pre-amplification +18dB
Pre-amplification 14dB
Splitter -6dB
Final amplification +17dB
Combiner +6dB
Output ~ 400W
Digital
Exciter
RF Power Amplifier
Directional
Coupler
TS1
input
Band Pass
filter
10-20dB
shoulder
reduction
Insertion
Loss of
0.6dB
Band Pass
Filter
Feedback
Samples
for power
metering
Directional Coupler
Single Probe
provides samples
for pre-correction
(non-linear and
linear)
Functionality

47
EXCITER FUNCTIONAL DESCRIPTION
Digital Inputs
Analog Inputs
Digital (IP)
and analog
remote
management
inputs
Reference
inputs (GPS,
1PPS etc.)
SIGNAL FLOW
SYNCRONIZATION CONTROL FEEDBACK
DISPLAY and CONTROL FUNCTIONS

48
Output is made up of
Two microstrips L3 and Balun B1.
C1 – C9 used to match transistor
Impedance to 50 ohm.
Inductor L5 and C17/C18
improve match at LF.
The length of the Balun B1 is 1/8 the central
frequency of mid UHF frequency i.e. 550MHz.
Input is made up of
Two microstrips L32 and
Balun B2.
R1/R2 LF Damping
C34/C35 RF
Decoupling for the Balun
R3-R6 and C35/C37
Provides damping function
that helps improve stability
AMPLIFIER
OPERATIONAL
DESCRIPTION

49
TRANSISTOR
DESIGN
UPDATE
NOW
NOW
SOON
FUTURE
Non-Doherty
Broadband

50
ANYWAVE

51

52
ANYWAVE
SEND US AN EMAIL
CALL US
(+66) 83 618-9333
(+1) 847 415 2258 (Ext. 1)
VISIT OUR WEBSITE

53
ANYWAVE Agenda
Anywave BTSI
Presentation July
2016

54
4. Advances in Solid State Technology
ANYWAVE

55
55
A Brief History Of
Solid State
Transmitter
Efficiencies
ANYWAVE Advances in Solid State Technology

56
Introduction
• Generation 1 released in the late 80’s was inefficient and unreliable
• Generation 2: Philips BLF861A and Motorola MRF372 (180 watt – 14dB Gain)
• Efficiency of 2nd Generation devices (digital operation) ~18%
• In 2008 came Generation 3 was introduced; the “50” volt LDMOS
• This resulted in lower cost per watt and helped reduced the cost of much higher
power transmitters
• Efficiency increased to ~ 25%
• The BLF888A became the standard for all manufacturers
• However, efficiency of these devices “stalled” at the 25% level
• Improvements could be made in other areas of the transmitter but most only saw very
small improvements in efficiency

57
57
To compete with vacuum tubes at high power namely the MSDC-IOT which had efficiencies in
excess of 50%... A much higher efficiency was needed:
Two new “ideas” to make solid state efficiency compete with the IOT…
• Drain Modulation (or Envelope Tracking)
• Doherty Modulation
Efficiency

58
PA
V dc
ATSC
Modulator
ASI
RF
Operates by modulating the DRAIN of a FET amplifier with the input signal so that the Power Supply
voltage follows the level of the input signal. The amplifier operates near the high-efficiency saturation.
Drain Modulation via Envelope Tracking (DM/ET)
Wasted Power
V dc
Resulting in a Drain Efficiency is about 25%

59
ATSC
Modulator PA
V dc
ASI
RF
DC - DC
Converter
Wasted Power
V dc
1mS
Resulting in a Drain Efficiency is about 30%

60
ATSC
Modulator PA
V dc
ASI
RF
Envelope
Detector
Supply
Modulator
Delay
Wasted Power
Resulting in a Drain Efficiency is about 40-50%

61
Drain Efficiency
• Now ~ 38%
• Future ~ 40-50%
• Theoretical maximum ~ 80%
• Sophisticated circuitry including DAC, Filter, I/Q detector and quadrature mixer required.
• Circuitry has to be included very near and on every amplifier, hence complexity increases
with number of amplifiers.
• Significantly higher component count decreases the mean time between failure (MTBF).
• Not chosen by most manufacturers due to complexity and additional costs

62
Doherty Modulation
A1
A2
RF
Input
Carrier Amplifier
Class AB (saturates at
high power input)
Peak Amplifier
Class C (Turns on
at high power input)
Paralleling two amplifiers devices; first operating in Class AB which
amplifies the average power level, and the second operates in Class
C amplifying just the peaks of the waveform. Output of two devices
are combined with a matched transformer.

63
63
• DOHERTY configuration improves linearity at the high power
input by complementing the saturation of the carrier amplifier
with the turn on characteristics of the peak amplifier
Doherty Modulation
• Originally designed by William Doherty of Bell Labs in 1934
• In 2008 NXP semiconductors (founded by Philips, now called Ampelon) released a transistor
“optimized” for Doherty amplifier applications. It has since been improved and commonly
available… Example BLF888

64
64
P out
P in
Saturation
Carrier Amplifier
Doherty
Modulation
Peak Amplifier
The addition of the
PEAK and CARRIER
Amplifiers
“Turn on”

65
65
• Amplifier efficiency
• Now ~ 40%
• Future ~ 40-50%
• Theoretical maximum ~ 50-60%
• Simple to implement with current circuitry available
• Due to two different devices feeding same load, impedance matching section is required
and hence is frequency dependent limiting broadband operation.
• Band-limiting output combiner/matching section can be configured to provide easy
“Broadband” operation; thru’ simple interchangeable parts. The “D” and “E” versions are
becoming more broadband overcoming this issue.
Doherty Modulation

66
Consumption – ISDB-T
10kW UHF
74kW Of
Wasted
Power
48kW Of Wasted Power
24kW Of Wasted Power

67
Doherty Class AB
and Class C
Standard Dual
Class AB
Average of 75.6 C
Operating Temperature
T1 = 62.9 C
T2 = 54.6 C
T1 = 75.7 C
T2 = 75.5 C
Drain Modulation via
Envelope Tracking
T1 = 58.9 C
Average of 58.7 C
Average of 58.9 C
Reduces
transistor
operating
temperature
by 23 C

68
68
Conclusion
Doherty Modulation is
• Easier to implement
• Does not reduce the reliability of the standard Fixed Drain (FD) Transmitter
• Reduces operating temperature of amplifier
• (Potentially increasing the reliability)
• Provides a large efficiency improvement
• (Tens of thousands of savings compared to FD)
• Offers the lowest cost transmitter

69
69
MPTV Range
1kW, 1.5kW, 2kW, 3kW
Non-Doherty : 2, 20, 100, 200
Doherty: 400, 600W
All available in both Doherty and
Non Doherty
LPTV Range
2, 20, 100, 200, 400, 600
The Choice is yours….

70

71
ANYWAVE

72
ANYWAVE
SEND US AN EMAIL
CALL US
(+66) 83 618-9333
(+1) 847 415 2258 (Ext. 1)
VISIT OUR WEBSITE

73
ANYWAVE Agenda

74
5. ISDB-Tb Transmitter Measurements
ANYWAVE

75
ANYWAVE ISDBT-Tb Transmitter Measurements
What are the KEY Measurements for an ISDB-Tb Transmitter?
• POWER
• Modulation Error Ratio (MER)
• Intermodulation Distortion (IMD)
And if possible….
• Harmonics (Out of band)
• Bit Error Rate (BER)

76
INTRODUCTION
• Broadcasting transmitters are subject to particularly stringent standards with respect to
broadcast signal quality
• Small faults can lead to service disruptions for many viewers
• A single instrument, such as the R&S® ETL TV analyzer* can perform all required ISDB-T
transmitter measurements
* Instead of the ETL the ETC or ETH can be a lower cost option

77
Two ways of making measurements
• OPTION 1: With External Test equipment
OR
• OPTION 2: With Anywave built in measurement system and Power calculation system using
Historic data and component manufacturers results

78
EXCITER/
MODULATOR
ENCODER
Transport
Stream
• The R&S®ETL TS has a
built TS generator. This
feeds an ISDB-T-compliant
MPEG-2 transport stream
(TS) to the TS input on the
ISDB-T transmitter.
• Or a compliant ISDB-T
encoder can be used.
• Even without a Transport Stream source Output Power calibration and the measurements of
MER, Shoulders can still be taken.

79
ENCODER
EXCITER/
MODULATOR
RF AMPLIFIER
RF BAND PASS
FILTER
RF DUMMY LOAD
TEST EQUIPMENT
R&S® ETL
R&S® NRP
PC
DIRECTIONAL
COUPLER “A”
Transport
Stream
RF On Channel
DIRECTIONAL
COUPLER “B”
RF On Channel
OPTION 1

80
Orthogonal frequency division multiplex (OFDM) signals exhibit a very high crest factor because
in extreme cases, all carriers could be overlaid or even eliminated at any given moment.
Where N = Number of carriers
It is important to know the crest factor so that the components that follow the transmitter – such
as the mask filter, the antenna combiner, the coaxial cable and the antenna, can be sized
adequately.
The crest factor (CF) defines the relationship between the highest occurring amplitude of the
modulated carrier signal and the RMS voltage of a signal:
CF = 20 10
CF OFDM = 10 10 2
Crest Factor

81
• The (CCDF) complementary cumulative distribution function includes the statistical
probability that a signal peak will occur.
• For ISDB-T, a theoretical value of > 40 dB results for mode III .
• In practice, it is limited to about 13 dB in the transmitter.
Crest Factor

82
0 2 4 6 8 10 12 14 16 18 20
10²
10
10ᴼ
10
1
-1
Instantaneous Power / Average Power Ratio
Probability%
CF = ~ 13dB
4% at 10dB
(4kW)
0.1% at 11.8dB
7.6kW
Assume at TPO = 400W
Crest Factor

83
Modulator Characteristics
I/Q Imbalance
ISDB-T modulators are essentially an IFFT signal processing block followed by an I/Q modulator. This I/Q
modulator can be either digital or analog. Anywave’s modulator is Digital. If an ISDB-T modulator uses
direct modulation, then the I/Q modulator it must be aligned cleanly to minimize the following influencing
factors:
● Amplitude imbalance
● Quadrature error
● Carrier suppression
It is difficult to measure these items without a spectrum analyzer, as poor carrier suppression is
recognizable as a notch directly at mid band and results in a contorted and compressed constellation
diagram in mid-band. Amplitude imbalance and quadrature error negatively affect the MER.
The Anywave modulator automatically corrects for minimum I/Q imbalance

84
Amplitude Frequency Response and Group Delay
• In analog television, amplitude frequency response and group delay were important
parameters for a transmission path between the transmitter output and the receiver input.
• Because of the channel correction in the ISDB-T receiver, significantly larger tolerances can
now be permitted without noticeable reductions in quality. The mask filter and antenna
combiners cause linear distortions.
• These linear distortions can be compensated by a pre-corrector within the transmitter. As a
result, however, the linear distortions appear reversed when measured at the transmitter
output.
• Therefore, the preferred method is to measure amplitude frequency response and group
delay after all filter stages.

85
Out-of-Band Emissions
There are THREE distinct components:
● Shoulder attenuation
Describes the power of the noise components close to the edge of the channel
● Adjacent channel emissions
Components within several MHz of the channel boundaries
● Harmonics
Components at multiples of the transmit frequency

86
Shoulder Attenuation and Adjacent Channel Emissions
• The mask filter is used to reduce these unwanted out-of-band emissions.
• Critical mask filters are used when an adjacent channel requires protection, making more
stringent requirements for attenuation of out-of-band emissions necessary.
• The high dynamic range of the signal after the mask filter makes it impossible to check
adherence to the tolerance mask directly using a spectrum analyzer. This is why an
adjustable notch filter is typically used to reduce the useful band power.
• The correct method is a complicated process using a tracking generator and additional notch
filters to attenuate the fundamental frequency so as not to overload the analyzer.

87
Harmonics
• In addition to adjacent channel emissions, multiples of the transmit frequency can also result
in harmonics. A harmonic filter at the transmitter output is used to suppress these harmonics.
• The R&S®ETL TV analyzer can be used to measure out-of-band emissions in spectrum
analyzer mode. Because the mask filter does not suppress these harmonics, but rather
affects only the channel near range, the harmonics can be measured directly at transmitter
output.
• The high dynamic range of the signal means that a suitable high pass filter must be used to
attenuate the useful channel by at least 40 dB.
• Notch filters (which are coaxial cavity filters that can be manually adjusted to the channel
being suppressed) are not suitable here because they do not attenuate in just the useful
band, but rather are repeated at multiples of the useful band.

88
Frequency Accuracy
• Single-frequency networks (SFN), in particular, place very stringent requirements on the
frequency accuracy of an ISDB-T transmitter of less than 10-9.
• The carrier frequency offset can be measured using the R&S®ETL in TV/radio
analyzer/receiver mode or a very accurate frequency counter.

89
• Complex Modulation Error Ratio (Complex MER) is a complex form of the S/N measurement
that is made by including Q (quadrature) channel information in the ideal and error signal
power computations. MER is defined by the following formula:
∑

∑
Where
MER is the Modulation Error Ratio in dB
are the Ideal I-channel and Q-channel symbols.
∂ I j and ∂ Qj are the Errors between received and ideal I- channel and Q-channel symbols.

90
Modulation Error Ratio
• A high MER value indicates good signal quality.
• In practice, the MER is 20 to 42 dB.
• A good ISDB-T transmitter has a MER in the range of approximately 35-38 dB.
• When receiving ISDB-T signals over a roof antenna with gain, a MER of 20 dB to 30 dB
would be measurable at the antenna port.
• Values between 13 dB and 20 dB are expected for portable receivers with a indoor antenna.
• The MER is the single most important quality parameter for an ISDB-T transmitter.

91
Constellation Diagram
• Good MER is indicated by small and concentrated
dots
Bad MER, represented by
scattered and distorted dots
in the constellation.

92
Bit Error Ratio
• ISDB-T provides an outer and inner error correction in the form of Reed-Solomon (RS) block
coding and convolutional coding, which are assessed using a Viterbi decoder. Both methods
are capable of recognizing and correcting bit errors in the data stream.
• All interference of an ISDB-T transmission path can be expressed as bit error ratios (BER).
• In the case of a functional ISDB-T transmitter, only the BER before Viterbi can differ from
null. It will lie in the range of 10–9 or less.

93
Phase Noise
• Can happen due to the local oscillator's instability
• In the OFDM modulation process, phase noise can cause a phase error in all of the sub-
carriers at the same time.
• It causes the constellation dots to “twist” on their axis.
474 MHz 762 MHz 802 MHz
10 Hz 86.3 82.0 81.2
100 Hz 106.9 102.7 102.3
1 kHz 118.8 115.3 114.3
10 kHz 124.0 120.8 120.2
100 kHz 124.6 122.0 121.9
1 MHz 141.4 140.0 139.5

94
Phase Noise

95
Efficiency and Performance of Digital TV Transmitters
REF: Average Carrier
Level
24dB
Un-corrected Class A-B Amplifier
IMD (Intermodulation Distortion) or Shoulders or Out of Band Mask

96
Level
42dB
Corrected Class A-B Amplifier

97
Level
17dB
Un-corrected DOHERTY Amplifier

98
Level
39dB
Corrected DOHERTY Amplifier

99
Testing an Anywave Transmitter with NO TEST EQUIPMENT
FREQ
617M
AGC
OFF
GPS
NOGPS
1PPS
ERR
CTRL
LCA
ADPC
OFF
• Frequency is measured in the exciter.
• With a GPS connected you can be assured of the accuracy.

100
FWD
100%
MER
43.5
LIMD
48
UIMD
49
FREQ
653M
Hz
+00000
MODE
MODE1
GI
1/4
PR
OFF
A-B-C-
13000
LAY
A
RATE
1/2
MAP
16QAM
TI
0
• Forward Power (+/- 3%)
• Modulation Error Ratio (+/- 1dB)
• Lower Intermodulation Distortion (+/- 1dB)
• Upper Intermodulation Distortion (+/- 1dB)
• On Channel Frequency
• Off Set Frequency
• Major status of modulation Modes: (GI, Layer,
Rate, Modulation type and TI).

101
VOL_9
8.72
VOL_12
12.07
VOL_50
49.37
PA_FWD
443.67
Power Calibration (Using the PAC Screen)
• The Forward Power will be calibrated at the
factory on the designated frequency.
• If frequency is changed this calibration will not be
correct.
To Re-calibrate the Forward Power
• The sum of the currents multiplied by the 50V
level divided by the frequency/efficiency factor =
the output power (+/-5%)
CUR1_ 50
11.2
CUR2_50
11.7
CUR3_50
12.1
CUR4_50
11.8

102
Filter Power
Band
Center
Band Edge Average Factor
100W 1.3 2.2 1.75 0.67
150W 1.0 2.0 1.50 0.71
250W 1.1 1.8 1.45 0.72
600W 1.2 1.6 1.4 0.72
1000W 0.8 1.4 1.10 0.78
1500W 0.6 1.1 0.85 0.82
1800W 0.6 1.1 0.85 0.82
2000W 0.6 1.1 0.85 0.82
3000W 0.6 1.1 0.85 0.82
7000W 0.6 1.1 0.85 0.82
Power Calibration
• Filters have a reasonably consistent
attenuation over frequency
• The lower the power rating of the filter
the higher the loss.
• Losses vary from 1.75dB to 0.6dB
• Multiply amplifier output power by
FACTOR to obtain real TPO.

103
0.2
0.22
0.24
0.26
0.28
0.3
0.32
0.34
0.36
Efficiency Factor
200W (Two transistor) OFDM (DVB-T2 and ISDB-Tb)
Example: Frequency 593MHz. Power Required 200W after the filter. Power factor at 593MHz = 0.28
Filter loss is 0.72dB for a 250W filter. There are two transistors in a
VOL_50 (50V PSU) = 49.87 CUR1_50 and CUR2_2 should read (ON AVERAGE)
200 / 0.28 / 49.87 / 0.72 / 2 = 9.95 AMPS i.e. 9.95 Amps* = 200W after filter output +/- 5%
* Average of each transistor.

104
0.2
0.22
0.24
0.26
0.28
0.3
0.32
0.34
0.36
Efficiency Factor
400W (Four transistor) OFDM (DVB-T2 and ISDB-Tb)
Example: Frequency 533MHz. Power Required 400W after the filter.
VOL_50 (50V PSU) = 49.97 CUR1_50, CUR2_2, CUR3_50 and CUR4_50 should read (ON AVERAGE)
400 / 0.33 / 49.97 / .72 / 4 = 9.95 AMPS i.e. 8.42 Amps* = 400W after filter output +/- 5%

105
0.2
0.22
0.24
0.26
0.28
0.3
0.32
0.34
0.36
Efficiency Factor
1500W (Six transistor, three amplifiers) OFDM (DVB-T2 and ISDB-Tb)
Example: Frequency 497MHz. Power Required 1200W after the filter.
VOL_50 (50V PSU) = 49.97 CUR1-6_50, should read (ON AVERAGE)
1200 / 0.35 / 49.97 / .82 / 6 / 3 = 4.65 AMPS i.e. 4.65 Amps* = 1200W after filter output +/- 5%

106
Anywave will provide customer with a Frequency versus
Power versus Transmitter software
Enter Frequency of operation,
Model number of transmitter
Power required
And the software will automatically tell you the
currents of each transistor to reach that power.
The transmitter then can be
calibrated very accurately at any frequency

107
Summary
• With Test Equipment make the following measurements regularly (one every six months)
• POWER
• Modulation Error Ratio (MER)
• Bit Error Rate (BER)
• Intermodulation Distortion (IMD)
• Harmonics (Out of band emissions)
• Without Test Equipment
• Transistor currents
• MER
• IMD

108

109
ANYWAVE

110
ANYWAVE
SEND US AN EMAIL
CALL US
(+66) 83 618-9333
(+1) 847 415 2258 (Ext. 1)
VISIT OUR WEBSITE

111
ANYWAVE Agenda

112
7. Safety and Maintenance
ANYWAVE

113
Safety
• SAFETY FIRST. When appropriate wear goggles, take off your rings and watches, tuck in your shirt.
• When working on “hot” equipment .. Keep you hand in your pocket
• Don’t work when you are tired.
• Don’t drive to the site too quickly
• Try to work in teams
Inspection
• Visual inspections can resolve most issues. Visual inspection should be
done with Power OFF. Useful tools .. Power flash light and mirror.
Reliability
• Most RF systems are reliable.. It is usually the low voltage stuff that fails
first.
• Most problems occur due to control circuits.. Know how the control system
works before there is a problem
ANYWAVE Safety and Maintenance

114
Environmental Conditions
• A HOT and DIRTY transmitter is an unhappy transmitter!
• Unhappy transmitters FAIL.
• Try to keep the transmitter site as clean as possible. Clean the
transmitter floor, clean table tops regularly, and clean any air filters.
• Make sure the room is air conditioned. Make sure the room
temperature does exceed 30 degrees C (85 F).
• Make sure there is plenty of air flow around the
transmitter.
• A nice feature is to include a stand alone duct for the
transmitter about 30 cms above the top of the
transmitter. And let the hot air simply exhaust, a
small exhaust fan can be included if the duct is
longer than 3 meters.

115
FWD
100%
MER
38.5
LIMD
43.5
UIMD
44.0
Forward Power
0 – 100%
Upper
Intermodulation
Distortion (UIMD):
20 – 60dB
Modulation Error Ratio
(MER) 25 – 50dB
Lower
Intermodulation
Distortion (LIMD):
20 – 60dB
POWER 100% = 0dB
Meter readings

116
Grounding
• The tower and incoming transmission line should be bonded
to the building lightning protective ground
• The Transmitter and electrical panel should be bonded to
the building lightning protective ground
Grounding RodsBelow Ground
Tower
Transmission Line
Transmitter Electrical
Panel

117
• CHANGING CHANNEL
• If your amplifier is Non-Doherty
• The process is simply
• Change the exciter frequency
• Re-tune or replace the filter on the correct
channel…
• Re-calibrate the forward power.. Done!
• However, with a Doherty Hi-Efficiency amplifier… it is not so easy

118
• Hi-Efficiency Doherty Power Amplifiers based on
the BLF 888B device provide high efficiencies
(50% efficiency) but with narrow band operation
• The Anywave Doherty PA design has multiple
sub-bands across UHF, and so re-tuning a
Doherty PA involves replacing the three PA
circuit boards (shown) with a circuit board that
covers the desired channel frequency.

119
• First remove the boards from the amplifier.
• To remove the board you must
• Access the power transistor board
• Remove top amplifier panel
• Remove inner shield cover
• Remove all the screws from the printed
circuit board (about 40)

120
• De-solder the power supply wires (2)
• De-solder the transistors and combiners
(to be re-used)

121
• Replace the board with a new board of the
correct sub-band

122
• Once the circuit boards are
replaced, the power transistors and
combiners are re-soldered into
place
• All screws replaced
• Power supply wires re-soldered
• Apply AC power to amplifier

123
• After the amplifier is now complete
and ready to operate, the only thing
left to do is re-bias the transistors to
the correct level.
• This is accomplished by adjusting
the potentiometers to the correct
idle current (~0.5A). The idle current
is monitored on the web interface
via the RJ45 connector on the rear
of the amplifier. There are two
potentiometers per transistor (four
total) for the board.

124
Summary
The key to success is
• Provide protected power
• Thoroughly ground all equipment
• Regularly check tightness of all connectors
• Avoid using tools on RF connections less than 7/8” EIA flanges
• Keep accurate records (initial snap shot of operation, then monthly)
• Measure the SNR, IMD, Forward Power and Reflected power regularly (monthly)
• Monitor PA device currents and temp – be sure do not reach max (monthly)
• Keep the transmitter properly cooled
• Keep the transmitter and the transmitter building clean
• Don’t try to fix a working transmitter!
• SAFETY FIRST.. No one ever died because they could not watch your TV station !

125

126
ANYWAVE

127
ANYWAVE
SEND US AN EMAIL
CALL US
(+66) 83 618-9333
(+1) 847 415 2258 (Ext. 1)
VISIT OUR WEBSITE

128
ANYWAVE Agenda

129
7. OCDR and SFN’s
ANYWAVE

130
What is an OCR and a Translator
13
0
 OCR: Process the input signal by eliminating the “echo”, boost it and re-send it at the same
frequency as the received frequency
 Translator: Usually perform demodulation and decode to the received signal, and can be re-
send at any frequency desired
ANYWAVE OCDR and SFN

131
• OCR uses the same frequency for re-transmitting (fin=fout)
• When the processing delay of OCR is much smaller than the guard interval, the re-
transmitted signal and the original signal can form a SFN
• OCR is one of the most popular way to set up SFN
• Disadvantage of OCR
• The transmitted power is limited by the “echo”
• The quality of transmitted signal is easily deteriorated and can be a interference to other
tower
• Advantage of OCR
• Doesn’t require additional transmit network
• Easier installation and lower cost
• Doesn’t require GPS as reference signal
13
1
Interference Cancelling can
overcome the disadvantage
of OCR!
OCR and Single Frequency Network (SFN)

132
Echo Interference in OCR
Conclusion: The system gain of OCR is severely
limited by the system isolation. Therefore how to
increase the isolation is the key to OCR application!
G: System Gain
E: System Isolation
H: System transfer function

133
Interference Cancellation System (ICS)
Z is the phase relationship between the input
and the output

134
Echo Types
1: Direct coupling between receiving antenna and
transmitting antenna
2: Reflection of far-away mountain
3: Reflection of nearby building
4: Reflection of moving object

135
Echo Cancellation

136
Echo Cancellation in SFN

137
Concepts in Echo Cancellation
Signal Length: Length of
received signal channel impulse
response
Echo Delay: The delay between
echo and received signal
Echo Window: Length of echo
channel impulse response
Process Delay: The delay of echo
cancellation process

138
OCR System Gain Example (w/o ICS)
Assume:
Received signal level:-50dBm
Antenna isolation:80dB
Conclusion:
Max system gain: Antenna isolation- 10dB = 70dB
Max transmitted power: Received signal power + max system gain= -50 + 70 = 20dBm

139
Assume:
Received signal level:-50dBm
Antenna isolation:80dB
Conclusion:
Max system gain: Antenna isolation- 10dB +30dB= 100dB
Max transmitted power: Received signal power + max system gain= -50 + 100 = 50dBm
OCR System Gain Example (with ICS)

140
Key Spec in ICS
Echo-to-Signal-Ratio
But most of all…
MER!!!!

141
Echo-to-Signal-Ratio

142
Reasons of MER Deterioration
• The MER of received signal
• The linear and non-linear distortion of the transmitted system
• Echo Ratio

143
Anywave Gap Filler with ICS
EOCR8000
PA100W
PA20W
PA200/400W

144
Anywave OCR Features (1)
• Auto Shutdown/Turn ON Function：
• When the main transmitted tower shuts down for maintenance, our OCR will shut down
automatically; when the main tower resumes transmitting signal, our OCR will turn on
automatically. No manual intervention is required.
• Signal Quality Auto Detection:
• When the received signal quality, echo level or re-transmitted signal quality has
changed, our OCR will adjust its transmitted signal level automatically. If transmitted
signal cannot meet broadcasting requirement after the adjustment, the OCR will shut
down its output automatically. No manual intervention is required.
• Patented AECTM (Adaptive Echo Cancellation) technology continuously, automatically, and
adaptively eliminates dynamically varying echoes from the received signal, providing easy
installation, reducing engineering cost, and producing stable operation as well as excellent
performance

145
Anywave Features continued
Echo Cancellation Mode
• Echo Cancellation:30 dB (typical value)
• Echo Time Range:≤ 4 μs
• MER Loss
• 0 dB Echo: MER Loss ≤ 3 dB or MER ≥ 26 dB (depends on main signal SNR)
• 10 dB Echo: MER Loss ≤ 5 dB or
• MER ≥ 26 dB (depends on main signal SNR)
• Echo Time Range:≤ 4 μs
• Processing Delay:≤ 10 μs (including ICS and DPD）

146
Anywave Features continued
• Supports current digital and mobile TV standards including DTMB, CMMB, DVB-T/H, DVB-
T2, ISDB-T, ATSC, and ATSC-MH
• Patented AECTM (Adaptive Echo Cancellation) technology eliminates dynamically varying
echoes
• Powerful ADPCTM (Adaptive Digital Pre-Correction) provides superior digital correction of all
linear and non-linear
• Accurate ESSI (Echo Signal Strength Indicator) and RSSI (Received Signal Strength
Indicator) functions provide direct field signal condition assessment and easy installation
• Digital ALC (Automatic Level Control) function supports wide RF input range and eliminates
the LNA module
• Powerful anti-interference of adjacent channel

147
Application 1
Directional Reception and Omni Transmit in city
Transmitted Power Level:100W
Received Signal:-50dBm
Received MER= 25.2dB
Re-Transmitted Signal MER=23.5dB
Echo Ratio= 9dB

148
Application 2
OCR in outlying mountain area
Transmitted Power Level:20W
Received Signal:-70dBm
Received MER= 28dB
Re-Transmitted Signal MER=25dB
Echo Ratio= 15dB

149
Wideband Broadcasting System (WBS)
For OCRs

150
Wideband Broadcasting System (WBS)
A WBS system allows multiple Modulators,
Translators and OCDR’s to use the same Power
Amplifier
Uses ANYWAVE’s Patented WB PRECORRECTION
SYSTEM

151
Advantage of WBS
• Does not require high-power combiner, therefore reduce the complexity and cost of the
transmitter
• Easier to change transmitted frequency
• Particularly suitable for low-cost coverage application of multiple channels from the same
location

152
Disadvantage of WBS
Severe distortion without an efficient pre-correction

153
Wideband Pre-Correction Technology
With the appropriate Wideband non-linearity
correction system Intermodulation distortion can
be removed
Result:
Significantly higher output power per amplifier
Improved Non-linearity = better coverage
Example from 5 Inputs / 100W amplifier
- without WBCS = 1W
- with WBCS = 10W
(10dB improvement)

154
SINGLE FREQUENCY NETORKS (SFN)

155
SFN
Advantages:
- Better use of the frequency spectrum allowing growth for TV channels.
- Uniform distribution of radiated power
- Distribution increases system availability and reliability.
- The presence of multiple transmission points gives the receiver an
- Additive Gain - addition of multiple signals-
- and a Statistic Gain - more uniform coverage.
To implement SFN, i.e. synchronize the signals, Key parameters shall be observed:
1. Same transmission Frequency
2. At the same time
3. Same signal (BTS), bit by bit – No rearrangement of the MPEG Stream

156
SFN
The main parameters that influence a SFN, besides transmitter power are:
• Guard Interval (GI)
• Delay adjustment

157
SFN
• The GI defines the overlapping area in which an SFN is possible.
• If a receiver falls outside the area protected by the GI and continues
to receive signal from more than one transmitter, it won’t be able to
open the signal due to inter-symbol interference (ISI).
• i.e. it sees the second signal not as additive but subtractive
• The bigger the Guard Interval the less interference but the lower the
bit rate (reduced quality and or reduced number of programs)
1/4
1/8
1/16
1/32
252
126
63
26
76
38
17
8
G/I uS km

158
SFN
Two transmitters in SFN
If there is no overlap on coverage then
there is no interference issues.
TX A TX B

159
SFN
TX A
• The red area corresponds to the
area that can’t be larger than the
area in which the delay falls inside
the GI.
TX B
• A delay adjustment between transmitters allows the signal to be transmitted at the same time
(or with a delay that falls within the GI), allowing the receiver to capture this signal, making a
SFN possible.
• Transmitters must be fed with same
Broadcast Transport Stream at EXACTLY
the same time

160
SFN
• The delay calculations are made at the generating station
• Calculations have to consider the necessary time for the BTS to arrive at the repeater station
• Once all stations are synchronized the SFN is established.
• This delay calculation can be made manually or automatically.

161
SFN
Example
• TX A is 6km from TX B and 12km from TX C.
• TX A is generator station
• Using the propagation speeds it can be
determined that signal takes 20μs to get to B and
40μs to C
TX B
TX C
12km
TX A6km
• Result :
• Delay on TX A BTS = 40μs
• Delay on TX B = 20μs
• Delay on TX C = 0μs
• Additional fine adjustment may also be required
for :
• Antenna phasing and directivity
• Specific interference variation with each location

162
SFN
Example of GI adjustment
TX A + TX B gives interference
designated by the yellow area
TX A TX B
If there is a populated area outside of
the GI adjustment area (red circle)
There are two solutions:
1. Increase the Guard Interval, but this
will reduced the transmission rate
(quality and possibly quantity of
programs)

163
SFN
• Or adjust the delay to TX B to move
the protected area
• Increasing the delay on TX B we
make the region where these
signals arrive together be closer to
the transmitter B This allows the
populated area to become protected
by the GI.
• There was an intentional delay
alteration to move a good reception
area from a non-populated area to a
more populated one
TX A TX B

164
SFN
To further reduce the interference area
• Lower power on the furthest transmitter
• Use of more robust modulation parameters – however, this again will decrease bandwidth
and options of programming i.e. only SD instead of HD or UHF.
• Combined use of SFN/MFN, selecting a different channel for one of the stations
• Use of On Channel Digital repeaters in geographically advantageous locations

165
SFN
• Main SFN components
• An SFN is composed of various equipment's that have specific functions such as BTS
generation (encoders), distribution networks (fiber or microwave), delay inserters, modulators
(exciters) and synchronization systems.
• None of these additional items are required with OCDR
IMPORTANT: Distribution equipment cannot alter content or packet order in the BTS!
• Equipment used for BTS distribution must be transparent, meaning that the order of the
multiplex frame packets is not modified. Equipment used include IP radios, Digital microwave
equipment, optic fiber, and satellite links for BTS distribution.

166
SFN
Network Types:
SFN networks can be of two kinds depending on their operation mode:
- Dynamic Network
-It is the easiest to implement and the most used configuration, because the delays are calculated
automatically with base on the information in the NSI field of the IIP. For this the delay inserters must
receive the same 1PPS reference. Maintenace in this type of network is simplified by the automatic
calculations for delay, making replacements a simple task with no need to reconfiguration.
Static Network
• In this operation mode the delay calculations are not done by the system and the absolut delay info has
to be informed to the Network Adapter (TIME_OFFSET) being necessary only a 10MHz reference for
synchronization.
• It is more complex due to the fact that all delays in the distribution channel have to be known in order to
configure SFN correctly.

167
SFN
Dynamic
- Pros: Automatic Path Delay calculation
- Cons: In case of 1PPS reference failure, transmitter “mutes” not to interfere with whole network.
Static
- Pros: No necessity of 1PPS
- Cons: Necessary to know all delays in the network. If a piece of equipment is substituted, a new
calculation is needed. This info can be obtained from equipment manuals or by measurements.

168

169
ANYWAVE

170
ANYWAVE
SEND US AN EMAIL
CALL US
(+66) 83 618-9333
(+1) 847 415 2258 (Ext. 1)
VISIT OUR WEBSITE

ISDB-T Transmitter Design and Technology Advances

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (20)

Similar to ISDB-T Transmitter Design and Technology Advances

Similar to ISDB-T Transmitter Design and Technology Advances (20)

More from Frank Massa

More from Frank Massa (7)

Recently uploaded

Recently uploaded (20)

ISDB-T Transmitter Design and Technology Advances