RF Burns Posted November 14, 2006 Report Share Posted November 14, 2006 Hello, Say if I have two amplifiers connected in cascade with the following specifications:Apmlifier 1: Gain Noise Figure OIP3 15 dB 3 dB 15 dbmApmlifier 2: Gain Noise Figure OIP3 15 dB 5 dB 20 dbmNote: OIP3 = third order intercept point.I calculated the overall gain, the overall noise figure and the overall third order intercept point.Overall gain = 30 dBOverall noise figure = 3.146 dBOverall OIP3 = 19.586 dBm (= -10.414 dB)My question is: What does this level of OIP3 mean? I know how to calculate it etc., but not what it actually means. For example, what happens if my RF input was greater than 19.586 dBm??Any details you can impart will be much appreciated.RF Burns Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 14, 2006 Report Share Posted November 14, 2006 Google has many links to a definition of the 3rd Order Intercept Point. It basically is the output level where the intermodulation distortion becomes very noticeable and keeps increasing with increased output level.Your circuit's gain is 30dB so the OIP3 output level is 19.586dBm, not the input level. Quote Link to comment Share on other sites More sharing options...
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