Intermodulation distortion is the main problem with mixers. This example shows how to use the rf blockset circuit envelope library to test intermodulation distortion of an amplifier using twocarrier envelope analysis. The thd function computes the power ratio of the harmonics to the fundamental and. Get started with rf blockset makers of matlab and simulink. This example shows how to use the rf blockset circuit envelope library to.
Request pdf nonlinear distortion in wireless systems. This example shows how to analyze the harmonic distortion of a weakly nonlinear system in the presence of noise. Theoretical analysis of intermodulation distortion in ofdm signals in the presence of. Histogram of a random signal with normal pdf in matlab by uniformedia. The total harmonic distortion is determined from the fundamental frequency and the first five harmonics using a modified periodogram of the same length as the input signal. Im distortions imds at the output of pas are usually tested by adding two tones with equal. The second and thirdorder intercept points ip2 and ip3 are. The example contains a typical setup to perform harmonic distortion measurements thd, snr, sinad, sfdr, thirdorder intermodulation distortion. For instance, the error due to intermodulation distortion can also be modeled as. The modified periodogram uses a kaiser window with. Rf blockset lets you simulate nonlinear rf amplifiers and model memory effects to estimate gain, noise, evenorder, and oddorder intermodulation distortion. Rf blockset formerly simrf provides a simulink model library and simulation engine for designing rf communications and radar systems rf blockset lets you simulate nonlinear rf amplifiers and model memory effects to estimate gain, noise, evenorder, and oddorder intermodulation distortion.
Intermodulation distortion imd is a popular measure of the linearity of amplifiers, gain blocks, mixers, and other rf components. The extrapolated point where the curves of the fundamental signal and second order distortion product signal meet is the intercept point ip2. Pdf theoretical analysis of intermodulation distortion in ofdm. The two thirdorder intermodulation im3 products are at 2.
Whats the difference between the thirdorder intercept. The simulations are first carried out in simulink and matlab environments and later on it is synthesized. Interaction of intermodulation products between dut and. Modeling in simulink and synthesis of digital predistortion. Total harmonic distortion matlab thd mathworks france. Often abbreviated imd, it is an important metric of linearity for a. Intermodulation distortion considerations for adcs pdf. Introduction intermodulation distortion imd is a common problem in a variety of areas of electronics. Plot the signal spectrum and annotate the total harmonic distortion thd.
Since the second order im distortion products increase like s2 i, we expect that at some power level the distortion products will overtake the fundamental signal. Higher harmonics and intermodulation products are not labeled. This tutorial first defines imd with respect to adcs and then points out the precautions which must be taken when applying the definitions of ip2 and ip3 to adcs. This example shows explicitly how to calculate the total harmonic distortion in dbc for a signal consisting of the fundamental and two harmonics. Nonlinear elements, nonlinear behavior, intermodulation distortion, ip2ip3. Intermodulation distortion is one of the most interesting signal analyzer measurements. Pdf documentation rf blockset formerly simrf provides a simulink model library and simulation engine for designing rf communications and radar systems. This example shows how to analyze the harmonic distortion of a weakly non linear system in the presence of noise.
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