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Audio Video Processor Design by Ayodele Okuneye Ben Wojtowicz ECE 445 February 25, 2005 TA: Richard Cantzler Audio Visual Processor In today’s digital world, the proliferation of digital audio and video media playing devices is almost exponential, whether it is in the form of our daily communications with one another or in our leisure activities. Through the use of digital processing techniques, media signals can be manipulated easily to produce a wide range of outputs. This array of possibilities led us to select a small subset of effects for audio and video enhancement to showcase in our ECE 445 Senior Design Project. Objectives: Our goal with this project is to build a device that will take audio and video inputs, perform some user specified processing on the signals, and will then output them to their respective output devices for user observation. The inputs will be directly passed to their particular DSPs and via the user interface, will be processed accordingly. After being converted back to the analog domain, the audio signals will be sent through an amplification system and on to speakers, while the video signal will be output to a monitor. Benefits to the user: Provides an integrated device for audio and video processing Gives user control over audio/video enhancement Provides hands on contact with complex effects Project features: Master Audio Volume Active Audio Equalization Dolby Surround Sound Reverberation Image Noise Reduction Image Sharpness Control Schematics/Simulations: See attached Large Schematics(A.1), PSPICE Simulations(A.2-A.4), and Software Flowcharts(A.5-A.9) Schematic Descriptions: The hardware part of our project has four main subsections. They are: 1) Power Amplifier(A.2) a. Uses a non-inverting operational amplifier to provide voltage gain b. Gain is approximately 21 (V/V) c. Output load is an 8 Ohm speaker d. Output is approximately 50W 2) Bass Power Amplifier(A.3) a. Uses a first order analog (RC) low pass filter to pass the bass (wc ~ 300Hz) b. Uses a non-inverting operational amplifier to drive the positive speaker terminal and an inverting operational amplifier to drive the negative speaker terminal c. Gain is approximately 42 (V/V) d. Output load is an 8 Ohm speaker e. Output is approximately 70W 3) Power Supply(A.4) a. Supplies the positive and negative voltages for the operational amplifiers b. Uses a transformer and a full wave bridge rectifier followed by very large time constant low pass filters to achieve DC output c. Output is approximately +/- 35V d. Ripple is extremely small (~37mV) 4) Interconnections/Grounding(see A.1) a. High grade coaxial cable (RG-174) will be used to transfer the signals from point to point to avoid noise injection b. All input and DSP send/return jacks (except Video send) will be isolated ¼” switch jacks to prevent improper grounding and also to ground the input when no signal is present (reduce noise with no input) c. Star grounding will be used to avoid ground loops and noise injection The software can be broken into to 6 main subsections. They are: 1) Master Volume a. User controlled variable gain for both channels 2) Active Equalization(A.5) a. 8 Band pass filters with user controlled variable gains 3) Dolby 5.1 Surround Sound(A.6) a. Inputs Left and Right Audio b. Processes inputs to simulate Left, Right, Center, and delayed Surround channel c. Bass channel is derived from Center channel in analog circuit(A3) 4) Reverb(A.7) a. Uses basic Schroeder Reverb topology b. Summation of the result of 4 Comb filters is fed into 2 Allpass filters 5) Video Effects(A.8) a. Will use a high frequency emphasis filter to sharpen the image b. TBA – possibilities include noise reduction, pixelation 6) GUI(A.9) a. Input point for all user defined variables using available Matlab tools Performance Requirement: Given user inputs, the interface should adjust operational parameters of the two major blocks (Audio and Video Processors) in our system and should impose a measurable change on the output (gain or channel response for audio and MSE for video). The power amplifier should amplify the power of the inputs signals for output to speakers (50W of output power). Tolerance Analysis: The most important component to the success of our project is the power amplifiers. If the power amplifier fails the result will be no audio output under any circumstances whereas if other components in the system fail, the system will not collapse. Therefore the power amplifier should be able handle a wide array of inputs from the power supply or the DSPs. The limiting case will be that the components of the amplifiers do not undergo any critical failures (i.e. explode) due to somewhat reasonable inputs (i.e. voltage sag). A basic list of tolerances is below. Power Amp o Should pass without distortion all audio signals within specified amplitude range (~1V Peak to Peak) and limit signals exceeding the range to +/VCC o Frequency Response should include the entire audio range (0-20KHz) o Noise Floor of the amplifier should be low to maintain high SNR o Should tolerate normal grid and environmental fluctuations (ie. Brownout, Voltage Peak, Temperature) o Output Level (~40-60W at 8 Ohm) Cost Analysis: Part # 75-TVA1376 30BJ500-20K 30BJ500-56K 283-220K 75-225P100V0.01 686-17512 30BJ250-1.1K 550-NMJ4HFS 550-1005 1KQBK-ND 1.5KQBK-ND 2C25Z5U102M050B 546-167P50 LM3886 Manufacturer Sprague Xicon Xicon Xicon Sprague Volex Xicon Neutrik Neutrik Yageo Yageo Sprague Hammond National Semi Radio Shack Radio Shack Lowes Lowes BUD BUD Littelfuse Alcoswitch ECE Stores MCM Electronics Kobiconn Description 500uF 100V Electrolytic Capacitor 20K 1/2W Carbon Composition Resistor 56K 1/2W Carbon Composition Resistor 220K 3W Metal Oxide Resistors .01uF 100V Polyester Orange Drop Capacitor 18AWG 6'7" 3 Prong Power Cord 1.1K 1/4W Carbon Composition Resistors 1/4" Insulated Switched Mono Jack 1/4" Jack Nut 1/4W 1K Resistors 1/4W 1.5K Resistors 1uF 50V Capacitor Hammond 250VA 50VCT Power Transformer 68W Power Operational Amplifier 4.5"x6-5/16" PC Board 2-51/64"x3-45/64" PC Board Rubber Grommets for Transformer 250V 2A Ceramic Fuse 7"x13"x2" Aluminum Chassis 7"x13" Aluminum Chassis Top SGL 3AG Fuse Holder SPDT ON/ON 6A 125VAC Switch .625" Power Cord Grommet 3/4" Self Adhesive Rubber Feet RCA Phono Jack Price $4.16 $0.22 $0.22 $0.39 $0.56 $3.29 $0.22 $0.92 $0.13 $0.10 $0.10 $0.28 $52.06 $4.23 $4.29 $3.29 $1.04 $1.29 $12.30 $5.54 $0.39 $2.38 $0.29 $0.28 $0.58 Qty 2 8 8 4 15 1 15 9 9 3 1 1 1 8 3 1 1 3 1 1 1 1 1 4 1 Total $8.32 $1.76 $1.76 $1.56 $8.40 $3.29 $3.30 $8.28 $1.17 $0.30 $0.10 $0.28 $52.06 $33.84 $12.87 $3.29 $1.04 $3.87 $12.30 $5.54 $0.39 $2.38 $0.29 $1.12 $0.58 $168.09 AC-409 BPA-1596 354001 MTA-106D 920-0823 28-940 161-050 TOTAL The only part that is not in yet is the transformer. It will arrive on March 5. See attached data sheets for the amplifiers and transformer. Schedule: Week starting Jan 17 Jan 24 Jan 31 Feb 7 Feb 14 Feb 21 Feb 28 Mar 7 Mar 14 Mar 21 Mar 28 Apr 4 Apr 11 Apr 18 Apr 25 May 2 Ben Wojtowicz Class Begins Brainstorming Power Amp Design PA /Active EQ PA Final/Active EQ Final Design Review/PA Build Intro to C6711 Intro to Video Effects Noise Reduction Spring Break Mock Demo/Final Image Test PA/Active EQ/Noise Reduction Final Test/Interface Overall Test/Write Paper Demos Final Paper Ayodele Okuneye Class Begins Brainstorming Dolby/Reverb Dolby Final/Reverb Matlab GUI Design Review/Matlab GUI Intro to C6711 Intro to Video Effects Video Sharpness Spring Break Mock Demo/Final Image Test Dolby/Reverb/Video Sharpness Final Test/Interface Overall Test/Write Paper Demos Final Paper
"Audio Video Processor"