dth presentation

Information about dth presentation

Published on April 20, 2010

Author: bhavinpatel13

Source: authorstream.com

Content

Presentation on DTH : Presentation on DTH By: bhavin patel Index : Index What is frequency & frequency spectrum? What is audio signal? What is video signal? What is DTH (direct-to-home)? Block diagram of DTH. What are the equipment used in DTH? What is the function of each unit? What is the frequency? : What is the frequency? Frequency : The number of times per second an electromagnetic wave completes one cycle Hertz : The measurement of frequency Frequencies are measured in Hertz 10 Hz = 10 cycles per second1 kHz = 1000 cycles per second 1 MHz= 1,000,000 cycles per second 1 GHz = 1,000,000,000 cycles per second Slide 4: Analog Signal A continuous electromagnetic wave which may vary in amplitude or frequency Digital Signal A signal that is expressed by discrete states, usually 0 and 1 1 sec 1 sec 8-bit Sample Value = 10110101 Signal Types Slide 5: 1 Hz 1,000 Hz(1 kHz) 1,000 kHz(1 MHz) 1,000 MHz(1 GHz) 1,000 GHz(1 THz) HouseholdElectricity AMRadio TV ChannelsFM Radio Microwave Light Signal Fundamentals - Electromagnetic Spectrum Slide 8: Frequency Spectrum CATV for PAL B/G Slide 9: Frequency Spectrum CATV What is audio signal? : What is audio signal? Two types of audio signals: 1. analogue audio 2. digital audio Analog Audio : Microphone works by converting the pressure waves of sound into changes in voltage on a wire and changes in voltage match the pressure waves.  Speaker works like microphone in reverse that it is convert the electric signal into sound wave. Analog Audio Digital Audio : Digital Audio  Sampling rate limits the frequency range of the audio file and must be at least twice the frequency  The higher sampling rate will be to that of the original analog waveform What is video signal? : What is video signal? Video signal can contain the information of the picture, each pixels can contain the important information. Types of video formats : Types of video formats Composite Video Signal S Video RGB Signal Component Video Signal Slide 15: What is DTH? DTH stands for Direct-To-Home television. It is the reception of satellite programmes with a personal dish by viewers for a single connection or for multiple connections in the same premises DTH is the direct mode of transmission between ‘Broadcaster’ and ‘Viewer’. General block diagram of DTH : General block diagram of DTH Slide 17: Tunner : It is select particular channel in the rang from 48 MHz to 860 MHz Demodulator: Selected Channel demodulate and the signal fed to decoder. Decoder: It is the D to A converter. Out put of decoder is audio & video signal. Microcontroller: It is control the all the process perform by each block. Slide 18: Components of DTH Minidish antenna : Minidish antenna It is the parabolic reflector, it is receive the signal from the satellite and fed to LNBF. Low noise block down converter (LNBF) : Low noise block down converter (LNBF) It is receive the signal of ku-band and down convert into RF signal. collects signal from the minidish It amplifies the signal It switches between vertical & horizontal polarities It down converts the incoming frequencies Co-axial Cable : Co-axial Cable Co-axial cable provide the link between the dish and stb. A transmission cable consisting of an outer metal conductor enclosing and insulated from a central conducting core. Connector : Connector Connector is used to connect the LNBF and STB with the cable. Set-top-box (STB) : Set-top-box (STB) Set-top-box can demodulate the signal and than converted into audio and video signal. And it is given to television. Thank you : Thank you

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