ABSTRACT
This
project is actually based upon the designing of a Short range wireless USB-FM
Audio Transmitter which can transmit data contained in the USB flash drive over
short distance using ROHMR BU9458kv Semiconductor chip. The chip is designed in
a new packaging called VQFP- 64(Very-fine-pitch Quad Flat Pack). The project
has actually been done in two parts, designing & analysing. The designing
part has been explained with the help of schematics & circuit diagrams. The
first section is FM Transmission and the second is USB-mp3 module. The FM
Transmitter is designed by using two BC-547 transistors. The USB mp3- Module is
designed by using ROHMR BU9458kv Semiconductor chip. The mp3 songs can be
played directly from the USB flash drive by using MODE- 1(default mode) of the
semiconductor chip without programming it. Successful Transmission of audio
signal through the designed FM Transmitter is a proof of the correctness of the
design. The experimental results on FM transmitter ensure that design is
capable to transmit USB data if it is implemented completely on commercial
basis. USB Audio FM Transmitter is an Electronic device which, with the aid of
an antenna, produces radio waves. The transmitter itself generates a radio
frequency alternating current, which is applied to the antenna. When excited by
this alternating current, the antenna radiates radio waves.
CHAPTER ONE
1.0
INTRODUCTION
1.1 BACKROUND
OF STUDY
A
stereo FM Audio Transmitter with transmitter chip or microprocessor chip
support based on an all digital is presented. It has to be designed as a fully
integrated single – chip transmitter in a 3v – 10v/ a 90nm Cmos technology to
be compatible with digital deep – sub micrometer processes of audio receivers
and analogue audios.
Nowadays
mobile phones have a lot of multimedia compatibilities e.g. an integrated MP3
player. The proposed transmitter enables a mobile device to stream audio data
to a FM receiver which is popular and existing in most households, schools etc
worldwide. As mobile applications are the main target for the transmitter great
attention has been attached to saving power and area.
Therefore,
the presented transmitter work on a 3v supply and is aimed for using 80 MHZ and
above reference Crystal, Oscillator while still providing wide band frequency
modulation capability by varying its voltage using variable resistor,
transistor if need to be choose any of the both above.
Due
to the extensive research that I have done for actually implementing a design
to address the problem of eliminating wires and creating a wireless network in
which music files can be played I have come up with the following report. In
this report I have documented everything that we have done to create this USB
audio FM transmitter. This report provides an outline to the steps that I have
taken over the last year to create a working audio transmitter. Following this
report will allow anyone to recreate as well as understand primarily why and
how I went through the engineering process, ultimately creating my project.
1.2 STATEMENT
OF THE PROBLEM
This
project is a technical project which required the knowledge of electrical
component, to be able to meet up the trick is to behaviour of electrical
components either by variation of current across the individual terminal or
mismatch of components. The following tools and components are required for
this construction to be successful, which includes tools like, “Soldering Iron, Soldering Lead, Scrapper,
Lead Sucker, Carbon Paper (white sheet), Pen, Pencil, Eraser, Razor Blade,
Compas (pin), Wires, Generating Plants (generator), Picker, Scissors, Minifying
Lens, Case, Masking (paper) Tape, Table and Stole, A Set of Tool Box. Soldering
Paste etc”. “Electrical Components
includes, Transistors, Vero board, Resistors, Capacitors, Inductors, Light
emitting, Diodes, ICs, Jumper Wires, USB Port, Casey (cover), Schematics etc”.
Market and Background Survey
USB
Audio FM Transmitters have started to develop over the last two years. The
largest breakthrough with audio output fm transmitters has been by companies
such as Griffin, Belkin, and Monster; all who have developed audio fm
transmitters that can be incorporated with Apple Computer’s iPods. These audio
transmitters are plugged into the iPod and use the iPod’s battery power to
transmit the audio signal from the iPod.
CONCEPT OF MODULATION AND DEMODULATION
Modulation is technically
the process of combining an audio frequency signal (low frequency signal) with
a high frequency oscillator. However the audio frequency signal which is being
transmitted super imposes on the carrier wave that transports it to the output
of the radio frequency amplifier into the antenna this audio frequency signal
otherwise known as modulating signal is being amplifier by the radio frequency
amplifier in order to overcome air impendence as it travel from the transmitter
to the receiver.
Demodulation
in the other hand is the process of separating or recovering the signal
(modulating signal) from the modulated earlier wave it is the opposite of
modulation and it is performed at the receiving end (radio receiver.)
TYPES OF MODULATION
There are three types of modulation
namely amplitude modulation (AM) frequency modulation (FM) and phase modulation
(PM)
1.
Amplitude modulation (AM) is the types
of modulation in which the information signal (audio frequency signal) varies
the amplitude of the earlier wave without changing it’s frequency. As the name
implies it is only the amplitude of the earlier wave without changing it’s
frequency. As the name implies it is only the amplitude that is being varied
while the frequency is kept constant as the wave travels
2.
Frequency modulation (FM) is the type of
modulation is which the modulating signal varies the frequency of the carrier
wave here it is only the frequency of the signal in frequency modulation
carrier information (intelligence) is carried
is variations in its frequency.
3.
Phase modulation (PM) is the type of
modulation that varies the phase of the radiated wave at the modulating
frequency and by an angle, which is proportional to the amplitude of the
modulating wave from.
1.3 OBJECTIVE
OF STUDY
The
objective of this project is to construct an electronically operated system
known as FM transmitter capable of transmitting a frequency modulated signal
with a little or no distortion into the atmosphere for dissemination secondly
to aid the gradating student into a season research activities that will carry
them along during the professional practice as a scientist
USB
audio FM transmitters are “a new way of allowing people the capability of
taking advantage of MP3 files stored on the computer, and I do believe there's
a market for it. People have this whole library on their computer and they want
to listen to it in another room,2" said Connie Wong, an analyst at Semico
Research in Phoenix, Ariz. According to Semico Research, the MP3 portable player
market will see an annual compound growth rate of 30.4% between 2002 and 2007.
When
the Aurius came out, towards the end of 2003, "a lot of online Internet
connected audio products, which are capable of moving the audio portion signal
across the house, haven't really caught on yet," In-Stat/MDR's Mike Paxton
said. "It's not to say they aren't coming, but they might be a little bit
ahead of the power curve."
Now
that it is 2005, and iTunes as well as iPods are dominating the market, the
power curve is here. The need for USB audio radio transmitters is greater than
ever.
Functional Requirements
This
device is compatible with personal computers using Windows XP. The device is
powered from a single USB port and is installed by the computer as an audio
device as soon as it is plugged in. When opened, audio files are automatically
sent to the hub and then the radio transmitting device. A graphical user
interface (GUI), allows the user to input a desired FM frequency from a drop
drown menu. When the frequency is selected from the GUI it is sent to the USB
Audio device where the music is modulated with the frequency for transmission.
The 18F2550 microchip microcontroller will control the output signal modulation
and send the finished signal to the transmitter. The transmitter will begin
transmitting automatically through an attached quarter wave antenna, so that
high quality audio output can be immediately listened to with the use of any FM
radio within a limited radius.
I
am powering the design solely on a 5V, USB, power supply. The amount of
hardware that am running from one 5V (100 mA) power supply is a large amount.
We have decided to relinquish some range in order to give more functionality to
one power supply.
Technical Survey
I
purchased all of my demo boards and components from the Internet. I acquired
the PIC from Microchip.com. I purchased another development kit that we thought
would help me further understand how to interface a USB component with a
computer, however, it helped very little. I acquired a USB hub device from
Texas instruments as a free sample for 180 days. I had originally planned on
using a design like this one but now I have modified the design. I am using a
hub similar to the TUSB2036EVM however; our main modification is the
elimination of the external power source jack. I plan on powering the device
from the sole USB power supply. I will be using the BH1415F Wireless Audio link
IC which is a very cost effective chip to modulate the signal with the sound
file. I have also used the Aurous USB Audio transmitter, as well as the FM-25B
Ramsey Development Kit in order to further our understanding of USB Audio
integration.
Whereas
this previous design included other components to create a larger transmission
range, my final design incorporates a less power consumption approach; giving
up transmission range for the need for only one power source. The
microcontroller (18F2550) sends the desired frequency (at which the audio files
are to be modulated) to the Wireless Audio Link IC and the wireless audio link
actually modulates the frequency, sending the modulated signal to the
transmission antenna.
The
main sales appeal of this project is the reduction of wires and the use of just
one power supply. Throughout the design process I constantly analyzed power consumption
as well as the rest of the circuit. By being willing to sacrifice a larger
transmission range I was able to compensate by using just one power supply.
Originally I had intended on using a boost circuit but after a complete
analysis of the circuit, I have decided not to use a boost and drive our
circuit solely from a 5V power supply through the USB port.
At
this point I believe that I have engineered this product to meet my technical
desires, as stated in previous statements.
1.4 SIGNIFICANCE
OF THE STUDY
The
project signifies a lot in the electronic communication system which
telecommunication is the vital aspect which is usually demonstrated through and
radio communication system the frequency modulation transmitter is applied in a
lot of instance frequency modulation is unavoidable used in FM radio stations
scattered all over the country whose advantage is paramount compared to its counterpart
AM modulation frequency modulation transmitted is equally used in a
miniaturized from as wireless morpheme.
Different
modulation techniques have evolved during the last decade to transmit &
receive the wireless signals over short & long distances, completely &
effectively. This project is utilizing Frequency modulation technique to design
Short range wireless USB-FM Transmitter using ROHMR BU9458kv Semiconductor
chip. The chip is fabricated in VQFP-64 Packaging (Very-fine-pitch Quad Flat
Pack). This is the key point of the research paper. Because, designing a Short
range wireless USB-FM Transmitter on such a small integrated scale can lead to
decrement in size of many audio-visual devices.
The
designed circuit cannot be implemented on breadboard due to its ultra-small
size. Therefore the PCB design is directly made after testing it on software
ProteusR version 6.9 to observe the accurateness of the design. The testing has
successfully done in the laboratory to assemble the semiconductor chip on PCB.
The main focus of the thesis has throughout remained on the working with
semiconductor chip of such a small level as VQFP-64(Very Thin Quad Flat
Package).
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