Test and measure techniques keeping pace with technology

Advanced software and more sophisticated wireless systems are at the heart of new techniques that are needed for testing some of today’s complex electronics equipment. The increasing integration of RF, microwave and high-speed digital technologies used in many systems, particularly mobile devices, is giving huge challenges to those who test and measure.

Mobile devices today need powerful processing capabilities, reliable wireless connectivity and long battery life. These needs are driving new developments in four major areas - faster chipsets, buses and memory; multiple radios that use multiple standards; new antenna techniques; and low-power operation.

For developers of equipment, isolated design and test tools are necessary but insufficient. The ability to transform a product idea into an actual product requires solutions that support specific needs. And the foundation of this is software and instrumentation working together in harmony.

To meet present and future needs, software must go beyond design and simulation to address areas such as signal generation, signal analysis and EMI behaviour.

But to get to this level requires connection between software and a variety of instruments. For example, signal creation benefits from links to arbitrary waveform generators capable of producing wide bandwidths and high resolution simultaneously and links to vector signal generators with I/Q modulation capabilities.

Signal characterisation requires spectrum or signal analysers that offer analysis bandwidths of up to 160 MHz today and even wider in the future.

The IEEE 802.11ac standard supports RF bandwidths up to 160 MHz, MIMO (multiple in, multiple output) antenna techniques and high-density 256 QAM modulation.

Software tools must enable engineers to view and troubleshoot all 802 modulation formats. To thoroughly test receivers and transceivers with reliable signals, USGs and ANGs need to support these bandwidths, formats and techniques.

For real-world testing of transmitters, tools such as signal analysers and vector signal analysers, software must provide the necessary demodulation capabilities plus essential measurements of signal quality.

In producing mobile devices, key issues are reducing capital expense and the costs of testing. At the same time, three key needs must be satisfied - support for multiple radio formats, fast testing and a reduction in overall test time. ‘One box testers’ (OBTs) using wireless communication test sets are designed to help manufacturers meet these needs. However, this is becoming increasingly challenging. For example, the list of formats supported by a single device is long and getting longer, for example: LTE, LTE-Advanced, HSPA, W-CDMA/HSPA, cdma2000/1xEV-Do, GSM/EDGE/EDGE –EVO, WiMAX, Wi-Fi, Bluetooth and GPS/GNSS.

As the cellular infrastructure evolves, mobile devices will be expected to support a range of new and legacy formats.

Speeding up test development depends on software that simplifies the creation of increasingly complex test plans. In supporting OBTs and other instruments that produce signals for multiple radio formats, software must also support the efficient creation of the standards-based waveforms needed to test receivers and transceivers.

As modulation formats get more complex, the signal-creating software will also need to become more sophisticated to enable a variety of possible signal impairments devices may face in real-world operations.

Achieving shorter test times becomes more difficult with device complexity. Multiple measurements for a single data capture are desirable, and as antenna methods evolve, it is necessary to efficiently automate testing of MIMO devices.

Doing all this and cutting the cost of capital investment depends on reliable measurement equipment. The latest generation of handheld instruments includes operating modes that are flexible enough to meet the needs of the novice and expert users. To increase efficiency, this newer generation of instruments can be configured with multiple capabilities in a single unit, such as cable and antenna test, spectrum analysis and vector network analysis.

Other built-in capabilities including a tracking generator, power meter, DC source and GPS reduce the number of items test and measurement technicians need to carry into the field.

These instruments are reflecting the deeper integration of RF, microwave and high-speed digital technologies into a single device that must have outstanding battery life and they are a reflection on the direction in which modern test instrument is moving.

This article is based on a paper called ‘Turning Ideas into Validated Production - Faster’ by Andy Botka of Agilent Technologies in the US.