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Amplifiers

186 bytes added, 20:25, 6 February 2018
Parameters to be considered while selecting LNA
* '''Noise Figure:''' The noise figure should be as low as possible.
* '''Linearity:''' If your signal is a broadband signal, the linearity of the the LNA matters. OIP3 (Third Order Intercept Point) is a measurement of the linearity of an LNA. Linearity means that the Harmonics are not produced. (Further explanation of OIP3 can be found [https://en.wikipedia.org/wiki/Third-order_intercept_point here])
[[File:Linearity.png|frame|center|Basic Characteristics of an LNA. Image reproduced from the datasheet of ADL5523, which can be found [http://www.analog.com/media/en/technical-documentation/data-sheets/ADL5523.pdf here]]]
* '''Matching Circuits:''' The input and the output must be matched to 50ᘯ for optimal performance. Every device has a Input and output impedance. These are the impedances looking from input and output respectively. For maximum transfer of power all the impedances of connecting components or tracks or wires should be same. If there is a mismatch the signals may get reflected and damage the amplifier. For more reading one can read Transmission lines. <br \>
If there is a mismatch between input of a connected device and output of the other device and matching circuit has to be designed for impedance matching. Example is shown in the following figure.
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