LIST OF TABLES:
CHAPTER 1: INTRODUCTION.
1.1-INTRODUCTION TO WIRELESS MODEM.
1.2-INTRODUCTION TO FREQUENCY SHIFT KEYING
CHAPTER 2: COMPONENT DESCRIPTION.
2.1-LIST OF COMPONENTS
2.2-DESCRIPTION OF FUNCTIONAL DIAGRAM
2.2.1 IC 555.
2.2.2 565 PLL.
CHAPTER 3: CIRCUIT DIAGRAM AND WORKING.
3.1-CIRCUIT DIAGRAM OF FSK MODULATOR USING IC555.
3.2-CIRCUIT DIAGRAM OF FSK DEMODULATOR USING PLL 555
CHAPTER 4: OPERATION OF FSK.
4.1-OPERATION OF FSK MODULATOR USING IC555.
4.2-OPERATION OF FSK DEMODUALTOR USING PLL 565.
CHAPTER 5: PROGRAMING USING MATLAB.
5.1-FSK MODULATION USING MATLAB.
5.2-FSK DEMODULATOR USING MATLAB.
CHAPTER 6: OUTPUT WAVEFORMS.
6.1-OUTPUT OF FSK MODULATOR.
6.2-OUTPUT OF FSK DEMODULATOR .
CHAPTER 7: CONCLUSION.
List of Figures
Fig a: Pin diagram of IC 555
Fig b: Pin diagram of NE 565
Fig c: FSK Modulator using IC 555
Fig d: Fsk Demodulator using NE 565
Fig e: Fsk Output model
Fig f: Output waveform of FSK Modulator.
Fig g: Output waveform of FSK Demodulator.
1.1: INTRODUCTION TO WIRELESS MODEM:
A wireless modem is a type of modem which connects to a wireless network instead of a telephone system. When a mobile Internet user connects using a wireless modem, they're attached directly to the wireless ISP (Internet Service Provider) and can then access the Internet. Mobile phones, smartphones, and PDAs can be employed as data modems to form a wireless access point connecting a personal computer to the Internet (or some proprietary network). In this use the mobile phone is providing a gateway between the cellular service provider's data network technology and Point-to-Point Protocol (PPP) spoken by PCs. Almost all current mobile phone models support the Hayes command set, a standard method of controlling modems. To the PC, the phone appears like an external modem when connected via serial cable, USB, IrDA infrared or Bluetooth wireless. Some cellular providers forbid this kind of usage, or charge an extra fee Wireless FireWire, USB and Serial modems are also used in the Wi-Fi and WiMAX standards, operating at microwave frequencies, to give a laptop, PDA or desktop computer an access point to a network. The modems may be as large as a regular cable modem to as small as a WiFi dongle/USB-stick. If combined with VoIP technology, these computing devices can achieve telephone-like capability to make and receive telephone calls. PCMCIA, ExpressCard and Compact Flash modems are also used. These card-modems can also have GPS included. Most early telephone-line modems used audio frequency-shift keying to send and receive data, up to rates of about 1200 bits per second. The common Bell 103 and Bell 202 modems used this technique. Even today, North American caller ID uses 1200 baud AFSK in the form of the Bell 202 standard. Some early microcomputers used a specific form of AFSK modulation, the Kansas City standard, to store data on audio cassettes. AFSK is still widely used in amateur radio, as it allows data transmission through unmodified voiceband equipment. Radio control gear uses FSK, but calls it FM and PPM instead. The CHU shortwave radio station in Ottawa, Canada broadcasts an exclusive digital time signal encoded using AFSK modulation.
1.2: INTRODUCTION TO FREQUENCY SHIFT KEYING:
Frequency-shift keying (FSK) is a frequency modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier wave. The simplest FSK is binary FSK (BFSK). BFSK uses a pair of discrete frequencies to transmit binary (0s and 1s) information. With this scheme, the "1" is called the mark frequency and the "0" is called the space frequency. The time domain of an FSK modulated carrier is...