Toshiba RF Receiver for HDTV Presentation 1: 10/21/2004 Team: Josue Caballero, Brett DiCio, Daniel Hooper, Efosa Ojomo, George Sewell

Work Accomplished in the Past Week  Met with our sponsor at Toshiba Aaron FosterAaron Foster  Toured the factory and assembly line  Discussed the current situation and defined the problem to be addressed  Outlined and determined the work that needed to be done by the group

Description of the Problem  Toshiba currently uses an antenna attached to the end of a Coax line to broadcast to a TV with a small receiver antenna  Current Design: Transmission distance of 2 to 3 centimetersTransmission distance of 2 to 3 centimeters Inefficient Tauroid-shaped transmission antennaInefficient Tauroid-shaped transmission antenna  Problems: Signal is being broadcast indiscriminately, being received on TVs that are not being testedSignal is being broadcast indiscriminately, being received on TVs that are not being tested Cannot determine the dB Gain of the received signalCannot determine the dB Gain of the received signal  Goal: Develop an antenna solution that can be used for multiple assembly lines without having to deal with errant signal noise and but with a consistent dB GainDevelop an antenna solution that can be used for multiple assembly lines without having to deal with errant signal noise and but with a consistent dB Gain

Left Side

Right Side

Top View

Current Setup  Workers unpack ‘guts’ and chassis and assemble them.  TVs placed on a roller line  TVs move from one station to the next, stopping at each station  First half of testing line is automated

Automation  Each station has a small antenna that lines up with TV ‘whip’ antenna  In front of TV, a computer makes adjustments Digital video camera inputDigital video camera input TV remote control outputTV remote control output

Manual Cable Placement  Required because of antenna signal strength is unreliable  Need to test v-chip and closed captioning at various signal levels for certification

Motivation  Labor cost for a simple task like plugging in a cable is high  Automated adjustment is free of human variances

Introduction to Antennas  Electronic components designed to send and receive radio waves  Used for transmission and reception of radio frequency signals like TV signals (signals can pass through non-conducting speed of light)  HDTV antennas are the same as conventional TV antennas

Different Antenna models  Dipole Antenna Simplest TV antennaSimplest TV antenna Omni-directional in plane perpendicular to axis of antennaOmni-directional in plane perpendicular to axis of antenna Variations include: the folded dipole (efficiency), bowtie dipole (bandwidth), and loop dipoleVariations include: the folded dipole (efficiency), bowtie dipole (bandwidth), and loop dipole Gain: ~2.5dBiGain: ~2.5dBi Example: “Rabbit ears” on TVExample: “Rabbit ears” on TV

Illustration of dipole antennas

Stacked Dipoles Two heads are better than oneTwo heads are better than one N dipoles will take in N times as much RF power as one dipoleN dipoles will take in N times as much RF power as one dipole Dipoles are commonly stacked horizontally (collinearly), vertically (broadside), and in echelon (end-fire). Dipoles are commonly stacked horizontally (collinearly), vertically (broadside), and in echelon (end-fire).

Different stacking methods

Reflector Antennas Radio waves reflect off a large conducting plane like a mirrorRadio waves reflect off a large conducting plane like a mirror They are very commonThey are very common ExamplesExamples  Screen Reflector  Parabolic Reflector (high gain, expensive)  Corner Reflector (less gain more bandwidth)  Paraboloid Reflector

Illustration of reflector antennas

Fundamentals  Maxwell’s Equations Understanding TransmissionUnderstanding Transmission  Vocabulary E – Electric fieldE – Electric field B – Magnetic flux densityB – Magnetic flux density Curl and DivergenceCurl and Divergence

Maxwell's Equations

Recieving  Maxwell transmissions  Antenna reacts Electromagnetic energyElectromagnetic energy CurrentCurrent Picture/SoundPicture/Sound  Creating an antenna Frequency designFrequency design

Interference Shielding  The factory has several production lines running alongside each other, because of the wireless transmission there is a high probability of interference  The signals can interfere and tests might not return good results  One possible solution is shielding

Shielding  Two styles of design: Active – Generating an opposing fieldActive – Generating an opposing field Passive – Blocking stray fieldsPassive – Blocking stray fields  There are several materials that can be used in shielding including plastic, concrete and metal  Method and Material is a question of cost versus need  We are going to researching the need for shielding and determining the best solution

To-Do List for Next Week  Finish an outline and draft of the requirements document for Toshiba  Obtain an understanding on how the current Toshiba design works  Determine a list of possible antenna designs/structures to be researched  Continue researching methods for shielding a test station from noise

Resources  pw.physics.uiowa.edu/plasma- wave/istp/polar/fig3.gif pw.physics.uiowa.edu/plasma- wave/istp/polar/fig3.gif pw.physics.uiowa.edu/plasma- wave/istp/polar/fig3.gif  sics/MaxwellEquations.html sics/MaxwellEquations.html sics/MaxwellEquations.html