How to deal with the challenge of the characteristic technology of power amplifier

We use NI pxi and labview to reduce the size, cost, and power consumption of a characteristic system and shorten the total characterization time.

"We use NI PXI to shorten the characterization time of new components from two weeks to about one day." ”

-Gary Shipley, TriQuint Semiconductor

Challenges：

Shorten the characteristic time of the increasingly complex wireless power amplifier (PA) Without sacrificing measurement accuracy or increasing equipment cost.

Solution:

Using the NI LabVIEW software and NI PXI Modular instrument to develop the power amplifier characteristic system, we increase the test throughput by 10 times times while reducing the cost of the asset equipment, the energy consumption and the physical space.

Author：

Gary Shipley-triquint Semiconductor

About TriQuint Semiconductor

TriQuint is a leader in High-performance RF solutions that involve complex mobile devices, defense and aerospace applications, and network infrastructure. Today, TriQuint offers innovative solutions to organizations around the world by using GaAs, GaN, saw, and Baw technologies. Engineers and scientists improve the performance of the product and reduce the total cost of its application with the help of TriQuint innovation.

The challenge of existing power amplifier's characteristic technology

Although the RF power amplifier is mainly designed to work in single band mode, modern power amplifiers are required to meet more diverse needs. In fact, the design of modern power amplifier can work in eight or more frequency bands, and can be used to include GSM, EDGE, WCDMA, HSPA, LTE and other modulation types.

In TriQuint Semiconductor, we need to test increasingly complex components at various frequencies, voltage levels, temperatures, and power ranges. A typical component's complete characterization process requires approximately 30,000 to 40,000 rows of data to complete the design test. With traditional rack-and-RF test equipment, each row of data takes approximately 10 seconds to collect, so that each individual component needs more than 110 hours to test.

Design Alternative PXI test system

In order to solve the challenge of shortening the characteristic test time of RF component, we developed a characteristic test system of power amplifier based on NI PXI, LabVIEW and Ni TestStand. Our power amplifier test Bench contains the following instruments:

· NI PXIe-5673 6.6 ghz vector Signal generator

· NI PXIe-5663 6.6 GHz Vector Signal Analyzer

· NI PXI-5691 8 GHz programmable RF Amplifier

· NI PXIe-5122 ms/s High Speed digitizing instrument

· NI PXI-2596 Double 6x1 GHz multiplex

· Mbit Digital I/O module

· Traditional Rack spectrum analyzer

· External power meter, power supply

· LabVIEW

· NI TestStand

· NI Gsm/edge Measuring Kit

· NI Measurement kits for wcdma/hspa+

We have updated our existing test plan with LabVIEW software to complete the same measurement sequence on the NI pxi test bench. Because of the faster measurement on the PXI test system, we configure the feature sequence to use the PXI test bench as much as possible and use traditional rack instrumentation only when needed.

The advantages of NI PXI

The main reason for determining the use of PXI is the ability to achieve a higher measurement speed without sacrificing measurement accuracy. Typically, RF measurements take up the majority of the time spent on a previous RF amplifier test bench. PXI uses high-speed data bus, High-performance multi-core CPU and parallel measurement algorithm to achieve the fastest possible test speed. In addition, the NI Gsm/edge measurement kit and the NI Measurement kit for wcdma/hspa+ use synthetic measurements, and all measurements can be completed using a set of Q data. We use these toolkits to measure power amplifier features such as gain, efficiency, flatness, ACP, ACLR, EVM, and Pvt.

Results obtained using PXI

By using PXI to complete most measurements of the power amplifier test bench, we shortened the power amplifier characterization time from two weeks to about 24 hours. In addition, significant improvements in measurement time have been observed in each GSM, EDGE and WCDMA measurement test. Table 1 compares the measurement time and speed of the traditional test bench and pxi test bench.

In a single measurement sequence, the PXI test bench completes 6 to 11 times times faster. Time is based on 100-frame measurements.

Conclusion

Because we use the NI PXI modular instrument, the characteristic time of the RF power amplifier is significantly shortened without sacrificing the measurement accuracy. We built a new PXI test system at the same or lower cost than the traditional instrument solution. We also expect to use NI PXI in future test systems.