FM CONVERTER

Team Members

Dan HarkinsTeam Leader

Beau Blackwell

George Henry

Shawn WelchDr. Georgios Lazarou

Advisor

Team ResponsibilitiesResearch Documents Web Site Testing Hardware

Fabrication

Dan Harkins

George Henry

Beau Blackwell

Shawn Welch

Project Significance

• Car radios do not have audio inputs

• Many cars only have a CD or cassette player

• FM converter can be used with FM radio

• Keeps the owner from having to buy and install entire audio system

Current Technology Options

• Cassette adapters are the most widely used means to play one audio device through another

• Cassette Player AdaptersExisting tape player neededExcess wiring can get in the wayLimited signal quality

Design Diagram

Signal from Audio DeviceSignal from

Audio Device

Transmit Converted FM signal

to FM receiver

Process Signal (Convert to FM

Signal)

Implementation

Design Specifications1. Operating Frequency: Operate throughout on the standard FM

radio range (87.9-107.9 MHz)

2. Weight: Target weight is eight ounces

3. FCC Requirements: Must be compliant with Part 15 of FCC regulations

4. Signal Clarity: The unit will be able to broadcast a stereosignal through the air

5. Packaging: Final product will be approximately 5” x 3” x 3”

6. User Interface: The unit will feature:• push-button style tuner • LCD to display the operating frequency• Input signal LED

Design Specifications7. Durability: Must be resilient to the bumps and bruises that can occur to a portable device.

8. Power Requirements: Will operate off:• Four AA batteries• AC converter• 12V DC Adapter9. Cost:• Prototype Components: $80 – 90• Mass production costs approximately

10- 20% of our prototype cost

10. Audio Input: The converter will use RCA audio inputs.

Benefits of RCA Connection

• Cord more commonly used and widely available• Greater versatility:

– RCA inputs offer the possibility to use both RCA and headphone outputs

• Increased cord life– Cords can be removable for storage

– User can replace worn or damaged cord without having to replace the entire unit

Benefits Over Tape Adapters

• Portability–No wires to connect to FM receiver–Light-weight–Can be used with any FM receiver

• Signal Clarity

– No tape “hiss”– Low interference– Automotive design minimizes interference

Benefits of FM vs. AM

• More widely used than AM radio– Consumers more familiar with FM dial

• Better signal to noise ratio

• Less interference than AM radio– Nearby electronic devices can cause “noise”– Even weather can cause static on AM radio

Typical Decibel S/N Ratios

AM broadcast / telephone: 25 dB (worst)

Audio Cassette Player: 35-45 dB

FM broadcast : 50-60 dB

Compact Disc: 90-105 dB (best)

Design Constraints

Radio Frequency

Signal Strength

Operation Voltage

Antenna Efficiency

Signal to Noise Ratio

Reliability

Pspice

Matlab

Performance Test

O-Scop

e

Spectrum

Analyzer

Test Specifications

Simulation

Jan Feb Mar Apr May Aug Sep Oct Nov Dec

Prototype

Simulation

Performance Testing

Debugging

Research

Final Documentation

FM CONVERTER