{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Design of narrow band pass filter

Design of narrow band pass filter - ntial amplifier on...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Demodulator (or) Receiver Modulator (or) Transmitter M-ary FSK Modulator MICRO-CONTROLLER PC Power Amplifier Transducer ED 16 NBPF-16 LS 2 ED 2 NBPF-2 LS 1 ED 1 NBPF-1 LNA + AGC Trans- du cer Micro- Controller rential amplifier mon source amplifier ential amplifier amplifier C HAPTER – І INTRODUCTION 1
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Communication is the process of establishing connection or link between two points for information exchange. A device that performs modulation is known as a modulator and a device that performs the inverse operation of modulation is known as a demodulator. A device that can do both operations is a modem (short for "Modulator-Demodulator"). Modem encodes the signal to be transmitted and also decodes the received data. Receiver is an element of the communication system. Basic block diagram of a Modem : A data transmission system using binary encoding transmits a sequence of binary digits, that is, 1’s and 0’s. These digits may be represented in a number of ways. The resulting signal is used to modulate a carrier. A data transmission system using binary encoding transmits a sequence of binary digits, that is, 1’s and 0’s. These digits may be represented in a number of ways. The resulting signal is used to modulate a carrier. There are different modulation techniques like Phase Shift Keying (PSK) Amplitude Shift Keying (ASK) Frequency Shift Keying (FSK) Phase Shift Keying : In this modulation the phase of the carrier is varied in accordance with the input bit i.e., for logic 1 the phase of the carrier Amplitude Shift Keying : The amplitude of an analog carrier signal varies in accordance with the bit stream (modulating signal), keeping frequency and phase constant. The level of amplitude can be used to represent binary logic 0s and 1s. We can think of a carrier signal as an ON or OFF switch. In the modulated signal, logic 0 is represented by the absence of a carrier, thus giving OFF/ON keying operation and hence the name given. 2
Image of page 2
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 literally implies using a pair of discrete frequencies to transmit binary (0s and 1s) information. In this modem design the frequency shift keying concept was used with a slight modification. Here corresponding to input bit sequence the corresponding frequency signal was sent to output . TRANSMITTER: Figure 1.1 The transmitting unit shown in circuit1 is built around a microcontroller. It is connected to PC via RS232 connection. The data (message) to be transmitted by the transmitting unit will be downloaded to the unit from the PC.Different frequencies are generated during the on periods of these square pulses depending on the input bit combination. The frequencies were selected to be in low range as this project was designed for being applied in under water communication.
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern