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Toshiba RF Receiver for HDTV. Team: Josue Caballero, Brett DiCio, Daniel Hooper, Efosa Ojomo, George Sewell. Presentation 1: 10/21/2004. Work Accomplished in the Past Week. Met with our sponsor at Toshiba Aaron Foster Toured the factory and assembly line
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Toshiba RF Receiver for HDTV Team: Josue Caballero, Brett DiCio, Daniel Hooper, Efosa Ojomo, George Sewell Presentation 1: 10/21/2004
Work Accomplished in the Past Week • Met with our sponsor at Toshiba • Aaron 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 centimeters • Inefficient Tauroid-shaped transmission antenna • Problems: • Signal is being broadcast indiscriminately, being received on TVs that are not being tested • Cannot 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 Gain
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 input • TV 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 surfaces @ speed of light) • HDTV antennas are the same as conventional TV antennas
Different Antenna models • Dipole Antenna • Simplest TV antenna • Omni-directional in plane perpendicular to axis of antenna • Variations include: the folded dipole (efficiency), bowtie dipole (bandwidth), and loop dipole • Gain: ~2.5dBi • Example: “Rabbit ears” on TV
Stacked Dipoles • Two heads are better than one • N 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).
Reflector Antennas • Radio waves reflect off a large conducting plane like a mirror • They are very common • Examples • Screen Reflector • Parabolic Reflector (high gain, expensive) • Corner Reflector (less gain more bandwidth) • Paraboloid Reflector
Fundamentals • Maxwell’s Equations • Understanding Transmission • Vocabulary • E – Electric field • B – Magnetic flux density • Curl and Divergence
Recieving • Maxwell transmissions • Antenna reacts • Electromagnetic energy • Current • Picture/Sound • Creating an antenna • Frequency 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 field • Passive – 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 • http://www-pw.physics.uiowa.edu/plasma-wave/istp/polar/fig3.gif • http://scienceworld.wolfram.com/physics/MaxwellEquations.html