Customer Solutions

Creating Next-Generation Phase Noise Analyzer with LabVIEW

Author(s):

Alexander Le Dain, Poseidon Scientific Instruments; Mehran Mossammaparast, ICON Technologies Pty Ltd., Australia

Industry:

Telecommunications

Product:

LabVIEW

The Challenge:

Creating a compact, integrated instrument that simplifies the process of phase noise analysis.

The Solution:

Building a custom hardware platform capable of accepting a variety of instrumentation modules integrated using LabVIEW and LabVIEW toolkits.

Building a Phase Noise Analyzer
Phase noise is a deviation from the ideal phase of a signal. It is commonly observed as the timing jitter of a periodic signal. Phase noise sets a fundamental limit to the throughput, resolution, and quality that can be achieved in any transmission system, whether it is optical, radio, cable, or satellite communication. It also sets fundamental limits to the sensitivity and resolution of radar systems.

Phase noise in the output of a system is determined by the phase noise in all its subsystems and components. Understanding how phase noise in a component contributes to the overall phase noise of a system is critical to the process of improving signal quality and increasing system throughput or sensitivity. Measuring phase noise in signal generators or measuring the additive noise of signal processing components has traditionally been a cumbersome, expensive, and somewhat mystifying process, giving it a reputation of being a “black art.”

Historically, engineers have purchased phase noise test sets off the shelf from major instrument suppliers, such as Agilent, or have had to build their own custom measurement systems. Either approach results in a large, integrated rack of instruments that is often the size of a household refrigerator. A major objective of the ODIN instrument is to overcome the large size, difficult configuration, and slow acquisition speeds of these traditional approaches.

Advanced workers in the area of phase noise analysis have sought to use the cross-spectrum technique to simultaneously correlate the noise detected in their measurement systems using a dual channel signal analyzer. The process of integrating the different instruments and optimizing and carrying out the various measurements that make up cross-spectrum phase noise analysis is complex.

The cost and associated mystique has kept phase noise analysis out of reach from all but the largest or most specialized electronics manufacturers. A compact, fully integrated instrument that made phase noise analysis simple and cost effective could vastly expand the range of applications and improve the quality and throughput of components and signal transmission systems.

Introducing ODIN
Poseidon Scientific Instruments (PSI) is known in the electronics industry as the manufacturer of the world’s lowest noise microwave signal generators. The company’s experience with RF sources and RF signal processing led them to develop a concept for a fully integrated, two-channel phase noise analyzer. The concept relies on combining a proprietary analog signal handling front-end from PSI with a digital signal processing back-end that refines and automates the sequence of industry-standard procedures for making standard single-channel or advanced correlated phase noise measurements. The new instrument, the ODIN Phase Noise Analyzer, released to beta customers in March 2003. The initial release operated on signals in the frequency range of 6 to 12 GHz and targeted PSI’s traditional customer base in the high-end performance radar, RF, and microwave markets.

ODIN’s major subsystems include a fully integrated phase lock loop and signal generator. A LabVIEW application controls all operations of ODIN and handles data acquisition, internal communications between instrument modules, signal processing, and operator interface functions. A provision for three input modules also exists, any two of which can be switched to the two-channel data acquisition analyzer.

Designers created ODIN from the ground up as a PC-based instrument to maximize its ability to be reconfigured with different instrument subsystems and to allow its signal processing functions to be readily upgraded and extended. After reviewing several alternatives, we at ICON Technologies chose LabVIEW as the software development environment because of its strengths in integrating a variety of hardware and subsystems and because of its strong credentials as a real-time signal-processing environment.

Although PSI clearly embraced the concept of ODIN as a PC-based instrument, they did not want the final product to look like a PC. We designed it to be familiar to users of traditional high-end signal analyzers, with a custom push-button panel, no mouse, and no keyboard. The final product clearly demonstrates the compact nature of ODIN as compared to the alternative of a complete rack of instruments needed for some systems.

As a fully integrated two-channel instrument, ODIN can take two simultaneous measurements and automatically calculate the spectrum, transfer function, or cross-spectral density of the two input signals. In the two-channel cross-spectrum mode, it passes correlated noise only, automatically rejecting the contribution to phase noise of its own mixers, amplifiers, and filters, among others. This allows those that are limited only by the Nyquist thermal noise of the input signals. In addition to being the world’s first fully integrated and automated phase noise analyzer, this instrument functions as a two-channel signal analyzer, making it a versatile and useful instrument in research, development laboratories, and production environments.

The Software is the Instrument
ODIN is priced competitively with more traditional instruments and offers far greater measurement flexibility, capacity, and expansion than conventional instruments. Ultimately, its greatest value is the extension of phase noise analysis as a standard technique into a much broader range of customers, through its ability to demystify what has previously been a tedious and sometimes daunting measurement for the operator.

ODIN’s most immediate use will be in the telecommunications industry in areas including telephony, wireless, digital radio, radar, and others that operate in the 6 to 12 GHz band. However, because of its modular design, customers can tune it to other commercially relevant spectral bands, bringing the benefits of phase noise analysis to other industry sectors.

We could not have brought the ODIN to market as successfully without taking advantage of virtual instrumentation technology. The flexibility of the PC platform running LabVIEW software to integrate instrument sub-systems and implement and sequence complex signal processing techniques was critical to successful development. The ability to extend and resequence the signal processing functions has presented opportunities to enhance the base instrument by adding new functionality and automating complex tasks.

ODIN demonstrates the benefits of using LabVIEW as a general-purpose technical programming language. Although the conventional LabVIEW look and feel was hidden, the initial feedback from customers was very positive when they discovered that LabVIEW powers ODIN. Customers saw this as a logical extension of their previous experience, which gave them confidence in the reliability, maintainability, and flexibility of ODIN’s software engine.

For more information, contact:
ICON Technologies

1st Flr, Alberman House, 20 Teddington Rd.

East Vic. Park, WA, 6100 Australia
Tel: +618 9470 4275,
E-Mail: mt@icon-tech.com.au