10 Broadcast Chain

8/3/2019 10 Broadcast Chain

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BROADCAST CHAIN


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Consists of:

Studio

Outside Broadcast (OB) Transmission Operation Center (TOC)

Production Operation Center (POC)


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Television Studio

Studio Floor

VTR Audio Prod. Room Lighting/

room Area Dimmers

Eqpt. CCU

Room


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Technical Facilities in a TV Studio

1. Camera

- video signal source

2. Camera Control Unit (CCU)3. Vision Mixer

4. Video Character generator (VCG)

- generates characters for credit line etc


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5. Digital Video Effects (DVE)

- generates effects eg, 3D, zoom etc

6. Frame Synchronizer

- to stabilize and synchronize incoming signals

eg. From satellite, OB etc7. Sync Pulse Generator (SPG)

- master clock that coordinates the wholesystem. Generates pulses to sync all video

signals.8. Audio Console

- mix and choose all audio sources


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Camera Control Unit (CCU)

Controls the various parameters of the camera:

lens aperture

zooming action

beam focus and the brightness control of

the camera

video gain sensitivity

blanking level

video polarity


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Vision Mixer

is a cross bar type of switch which allowsthe selection of any one of a large numberof inputs

Switching the inputs on to any of theavailable output lines or outgoing circuits

Mix/cut those signals

The inputs: cameras, VTRs, test signalsand outputs from special effect generators


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Sync Pulse Generator

A common source of deflection pulses suchas sync and blanking pulses are used tokeep the deflection circuits in phase with

other all the time. Provides the following controlling anddeflection pulses:-

- line drive or H-pulses at the rate of

15625Hz

- field drive or V-pulses at the rate of 50 Hz


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- System blanking pulses at H and V rate- Camera blanking pulses at the H and Vrate

Camera 1

Camera 2

Camera 3

Sync pulsegeneratorSPG


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CAM 1 CCU1 EDA EDA TO MONITORSPGM1

TO AUDIO/

CAM 4 CCU4 EDA VISION LIGHTING

VTR EDA MIXER EDA PGM 2

TO VTR

OB FRAME EDASYNC

VCG EDA SPG

VIDEO SYSTEM BLOCK DIAGRAM


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Transmission Operation Center

Transmits TV programs according to schedule

Its important feature is the on-air automation

Handled by BTS onair automation system

Integrated Control System

- a software base system where all controls ofmatrixes and machines are carried out via the

ICS Lan


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Production Operation Center

Main function is to distribute outsidesignals to any sections that required thesignals for recording

Comprise of:

- Master Control Room (MCR)

- VTR- International Room, handle all overseassignals. Has standard converters and vtrs.


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SIGNAL FLOW IN THE MCR (TOC-POC)

TEL.Link

to JRC.

Internal

sources

Internalsources

TOCMATRIX

50 x 50

CONTY

1

Ext.

Ext.

TOC OUT

MATRIX

10 x 10

CONTY

2

POC

MATRIX

90 x 90

TOC incoming

Dist.Amp. at

TOC i/p Rack

TOC - MCR

POC - MCR

Final TOC

output DAs at

TOC o/p rack

RTM.Link

to KL Tower.

to ASTRO

(via Maxis

Fibre)

to TEL.

Control

Centre JRC.

(via Tel.

Fibre)

MicroWave Room-8th Floor.

OAA

OAA

OB Link

from KL

Tower.

MicroWaveRoom.

TVRO.

TEL.

VTR-Rec

Computer

system for

Scheduling.

Scheduling Editors 1~14 (NT-Workstation)

Transfer

Facility 1~3

(Win 3.11

WS)

NT- Server

TEL.

Equip

.

TEL.Room

ICS

Integrated Control System

for routing switchers and

machine remote control.

On Air

Automation

INT. ROOM

VTR-Play

STD

1~5

AUDIT.

PERDANA

CONTY

3Internal

sources

Ext. OAA

Ethernet LAN

Open Net LAN


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TV Transmitters

Is a combination of video and audio transmitter Outputs from both are fed to a common

transmitting antenna through feeder lineconnected to a combining unit called diplexer.

Video is AM

Audio is FM

Tx operate in the UHF or VHF range.


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Video I/PAMP sync

regen

EqualizerPhasecompensation Video AMP

Crystal MO Multipliersx2 x3 x 3 RF AMP PA Driver 2stages Video o/pAMP VSBF andDiplexer

PAPA DriverAMPMultipliers

x2x2x3x3

FM

ModulatorPre-amp

AFC Xtal Osc.

Video

Audio

Output

Xmitting Antenna

10 kW

Filter Plexer

2kW

Block Diagram of a 10 kW VHF Transmitter


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Video signalis processed through:

Visual exerter unit consisting the video I/P ampand sync regenerator, equalizer and phasecompensator

Audio signalis processed in:

Aural exciter unit

Incoming audio frequency modulates FMcarrier frequency to the final sound carrier

frequency for the channel used


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TV Relay Systems

One of the common relay systems is theMicrowave Communication Link System.

Are e.m waves, wavelength : 1 m down to

1mm,frequency of 300 MHz to 300 GHz.

Normal frequency : 2 GHz, 7 GHz and 13 GHz.

Bl k Di f Mi TV R l


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Block Diagram of Microwave TV RelaySystem

ReflexklystronModulatedAmp

ModulatedAMP

Sound

Mod.Diplexer

KlystronAmp

Mixer Unit

IF Amp

LIM.Discriminator

Diplexer SoundDemod

Video Output

Audio Output

Video Input

Audio i/p

Transmitting Head

Receiving Head


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Microwave links are commonly used for :

1. Studio-to-Transmitter Link (STL)

- for the relay of programs from studio totransmitter

2. Outside Broadcast (OBs)- when live programs to be relayed fromremote places to transmitter or TV studios

3. Inter-Station TV Relay Systems

- interchange TV programs between TVstations


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Satellite Relay System

A communication satellite is one of thebest TV relay systems

Is essentially a microwave link repeater

Receives the energy beamed at it by anearth station, amplifies and returns it toearth at a different frequency to preventinterference between up link and down link

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10 Broadcast Chain