Unit 1 Assignment 1 Essay example

973 Words Jan 29th, 2015 4 Pages
Section 1-1
1. Define modulation.
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted.
*2. What is carrier frequency?
The frequency generated by an unmodulated radio, radar, carrier communication, or other transmitter, or the average frequency of the emitted wave when modulated by a symmetrical signal. Also known as center frequency; resting frequency. 3. Describe the two reasons that modulation is used for communications trans- missions.
1) Signal integrity 2) Power savings
4. List the three parameters of a high-frequency carrier that may be varied by
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Noise generated by electronic devices varies greatly, as it can be produced by several different effects. Thermal noise is unavoidable at non-zero temperature, while other types depend mostly on device type or manufacturing quality and semiconductor defects, such as conductance fluctuations, including 1/f noise. 16. Explain the difference between external and internal noise.
Internal Noise is that which a system generates on its own. For example in MicroProcessor, Inductance of lines connecting different gates or coupling capacitance between different lines may produce noise. In some systems, thermal excitation and deexcitation of Electrons may produce Noise. In Most Cases, such Noise is unavoidable. For example, if we are amplifying a signal by normal Amplifier, which has certain internal Noise, and if We make gain large to improve signal to Noise ratio, Noise gain will also increase!!! External Noise on the other hand comes from some external source. For example, in Microprocessor system, ripple voltage from power supply or voltage spikes may produce noise. This noise can often be reduced easily and may even be suppressed.
Section 1-4
23. Calculate the S/N ratio for a receiver output of 4 V signal and 0.48 V noise both as a ratio and in decibel form. (69.44, 18.42 dB)
27. A two-stage amplifier has a 3-dB bandwidth of 150 kHz determined by an LC circuit at its input and operates at 27°C. The

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