Study On The Design Scheme Of RF Pulse Test Signal And Memory Kernel Extraction

With the rapid development of wireless communication technology, thereare more demands for its core components RF power amplifier (PA), which arehigher power, higher efficiency, higher linearity and smaller volume. Thus, itforces the PA gradually stepping into the nonlinear workspace even saturationstate. As a result, the output of the PA shows nonlinear distortion characteristics.Meanwhile, the physical properties of PA itself making the current output havethe memory of the past input. The vector measurement-based parametricbehavioral modeling technology has been established by modeling the portnetwork of the PA devices. It can effectively describe the behavior characteristicsof the PAs. The static X-parameter model surpasses the classic small-signalS-parameter model, describing the nonlinear distortion characteristics of the PAs.Based on the steady-state response describing of the static X-parameter model,the dynamic X-parameter model introduces the memory kerel function to reflectthe memory effect. Therefore, the power amplifier’s memory kernel extractionand effectiveness check of the memory kernel are key points to the research.This paper specifically discussed the memory effect of power amplifiers. Itfirst introduces the essential theoretical foundation of the memory effect, whichis the dynamic X-parameter model. The paper provides the derivation processesstarting from the static X-parameter model. It also analyzes the forms and causesof memory effects. Then according to the characteristics of dynamic X-parameter mode, using the method of "two-value envelope" to design thePulsed-RF test signal. The test signal can change from arbitrarily envelopamplitude to arbitrarily envelop amplitude. One-tone double electrical levelhardware test platform need to be established to produce such test signals. Thispaper provides three signal designing schemes. The device under the test is a RFPA (ZFL-11AD) from Mini-Crcuits Company. Finally, the paper used the RFsimulation software ADS to verify the memory effect exists. The memory kernelextracted from ZFL-11AD by processing the test platform’s output data, the shortest time interval is1μs. In particular, the effectiveness of the memory kernelhas been verified.Through the verification of the device’s memory kernel, it validates thememory kernel function can effectively describe the device’s memory effect. Thedynamic X-parameter model can perfectly represent PA’s nonlinear characteristicalong with its memory effect. After extracting all memory kernels of the device,collecting all the data to build a memory kernel libiary, by calling the memorykernel library data to simuate and predict.