Step-by-step guide: How to deal with the five challenges of transmitter testing

Mobile data and voice services continue to require greater channel capacity

This is usually also true for wireless LANs.

As developers introduce various technologies to meet these needs

Each technology brings more challenges to transmitter testing

When setting up the analyzer for compliance measurements

This also becomes a challenge for the analyzer!

1.2~ Measurement of general and special standards

Around the major wireless standards

Signal analyzers can be equipped with dozens of different measurement applications

As shown below Example interface:

▲ The measurement software can display multiple measurements in split screens, helping users to gain a more comprehensive understanding of signal quality and characteristics. This LTE measurement interface includes constellation diagrams, detected positioning information, frame reports, and overall error reports. In order to optimize and facilitate troubleshooting, different colors are set for measurement results of different channel types.

▲ When performing ACPR/ACLR measurements on modern wireless systems, the specific setup is very complex. The figure uses non-contiguous carrier aggregation, and the complexity is particularly evident when cumulative ACLR is included in the configuration.

▲ In this OFDM EVM multi-measurement display of a WLAN signal, four traces are covered: EVM vs. symbol, EVM vs. subcarrier, constellation diagram, and EVM table indicators

On all analyzers:

◎ These software use consistent measurement algorithms that have been verified by Keysight in accordance with relevant standards;

◎ When the standards are revised and extended, these applications will be updated synchronously;

◎ Algorithms and application interfaces are shared, so users can easily become familiar with and get started, which can effectively reduce training and programming time.

At every stage of development and production

Accurate power measurements are critical

Choose the right tool: a signal analyzer !

For independent high level signals

The power accuracy of a signal analyzer is slightly inferior to that of a power meter

However, when it comes to RF transmitter testing, analyzers have the advantage

When measuring power in wireless systems:

Signal analyzers can effectively reduce broadband noise power (noise floor), thereby improving measurement accuracy and dynamic range, especially for small signals or signals close to the noise floor.

In terms of power versus time measurements:

Reveal the dynamic power characteristics of the channel during signal bursts, or reveal the dynamic power characteristics of signal frames.

It is important to have a comprehensive understanding of the spectral output of a wireless transmitter, including dynamic changes. This of course includes the presence of many transient signals, which can have very low duty cycles due to their spectral occupancy and pulsed nature. The asynchronous nature of communications and multiplexing mechanisms results in interfering signals with very variable duty cycles, which can be very troublesome.

Spectrum Analyzers and Signal Analyzers

The tool of choice for detecting and measuring spurious and interfering signals

It has more general and powerful analytical capabilities

A powerful tool for measuring spurious and other interfering signals

Wireless engineers are faced with the challenge of meeting specifications and ensuring their designs can coexist in a dense spectrum environment. EMI is a constant concern for wireless engineers. It is easier and less expensive to identify and avoid these risks in the early design and design verification stages.

Standardized measurements using common tools

You need a

Signal Analyzer with EMI Measurement Application

EMI pre-compliance measurements can be achieved

Traditional mobile devices require frequent charging, and keeping customers happy and standing out from the competition involves optimizing power management.

Understanding the trade-offs in power consumption:

Achieving reliable, power-efficient operation, especially at low or very low power levels, requires more engineering trade-offs and testing. A DC power analyzer that combines multiple DC sources with detailed power measurements is a convenient solution (Figure A). This relatively new product makes it easier to understand the details of power consumption (Figure B).

Development of any wireless system is a daunting task

Will be strictly restricted

And it is further complicated by the many trade-offs to be made.