Essays on Oscillator

555timer

Introduction The 555 integrated circuit (chip) is used in a variety of timer and oscillator applications. A 555 timer is used to provide time delays and oscillations and as a flip-flop element. The device has additional terminals provided to trigger or resetting purpose (Nair, 2006). During the time delay operation mode, time is precisely controlled by an external resistor and capacitor. While working as an oscillator, the duty cycle and the frequency are accurately regulated by two external resistors and a capacitor (Brumbach, & Clade, 2003). 555 is triggered and reset on falling waveforms. A typical 555 timer IC is ...

(QAM) Laboratory Report

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Objective: Components required: A carrier source, data source, phase shifter, multiplier, symbol mapping, noise channel, PCB board, phase scope and oscilloscope. Theory: There are two types of modulation technique namely analog and digital. QAM is a technique that uses both analog and digital modulation technique. It is the abbreviation used for Quadrature amplitude modulation. In analog modulation scheme it passes the two message signals by varying the amplitude of the two carrier waves using amplitude modulation method. In the case of digital modulation technique two digital bit streams are transferred in which ...

Lab reports on Quadrature amplitude modulation and Demodulation

Introduction Quadrature amplitude modulated is an electro-magnetic wave signal that employs two Quadrature signal carriers cos 2pfct, sin 2pfct, of which each of the signal carriers are modulated by an independent sequence of information bits. The transmitted signal assumes a wave form of this nature.

the values Amc and Amg are the two sets of amplitude that need to modulated. QAM can be viewed as a form of combined amplitude digital phase modulation and digital amplitude. The resultant transmitted QAM signal is a cosine wave which is expressed as shown below. umn(t) = AmgT (t) cos(2pfct + øn); m = ...