Spectrum analysers with greater accuracy and resolution are in demand

Spectrum analysers are now offered as multi-measurement instruments, stacked with features for various applications. And with the evolution of technology, these instruments are becoming even more sophisticated and accurate

By Richa Chakravarty

Wednesday, March 05, 2014: With technology and standards evolving in every industry, and with the widespread use of wireless broadband technology, the demand for spectrum analysers that have greater accuracy and resolution is on the rise. Spectrum analysers are primarily used to measure the power of the spectrum of known and unknown signals. They measure the magnitude of an input signal versus the frequency within the full frequency range of the instrument.

Technological advances

Spectrum analysers are now offered as multi-measurement instruments. With interesting technological developments and new application areas, spectrum analysers today offer flexibility. They are also suitable for modular software based instruments. Now handheld spectrum analysers are available which are very useful for field applications.

Ultra-wide capture bandwidth: Today’s wireless communications use sophisticated digital modulation schemes, which have a very wide bandwidth. These types of signals are displayed over a small portion of the spectrum at any given point in time. To address this bandwidth requirement in today’s RF domain, spectrum analysers offer more than 1 GHz of capture bandwidth.

Multiple testing capabilities: The evolution of ‘combination analysers’ is what the industry is witnessing these days. Spectrum analysers are now available as a combination of vector network analysers (VNAs) and spectrum analysers or of power meters cum signal analysers, etc. This makes it faster and easier to switch between different types of tests. Users can optimise product testing with these capabilities.

Spectrogram display: Most of the spectrum analysers today offer a spectrogram display. With dual window displays, the user can simultaneously acquire frequency and time domain information. In spectrogram mode, the X axis shows a line of the frequency spectrum with different colours representing the different power levels of various frequency signals, and the Y axis shows the time progress with the current spectrum, which always appears on the top of the display, with the previous spectrum to roll down towards the bottom.

Topographic technology: The topographic technology in today’s spectrum analysers enables signals to be displayed in various colours depending on the occurrence counts of each individual signal. The topographic mode is useful to detect the transient interference signal in the telecommunications system, or to clearly display the transient behaviour of various types of telecommunication modulations like frequency shift keying (FSK), complementary code keying (CCK) and orthogonal frequency division multiplex (OFDM).

Phase noise: High purity, high stability signals have become more important to the modern communication, aerospace and defence industries. Phase noise is one of the most crucial measures to evaluate the short-term stability of a signal. Therefore, an accurate, fast and easy-to-use phase noise measurement tool is critical in the R&D and manufacturing environments. Today, most players offer analysers with the phase noise measurement function.

The latest in the market

Vector signal analysers: In November 2013, Tektronix upgraded its MDO4000B series, which is a wide bandwidth vector signal analyser for advanced modulation analysis. This series comprises mixed domain oscilloscopes that feature significantly enhanced spectrum analyser performance and, when used with Tektronix SignalVu-PC, offer wide bandwidth vector signal analysis capabilities and deep support for WLAN 802.11. Known for its versatility and technical capability to tackle a wide range of test challenges, the MDO4000 series can capture time correlated analogue, digital and RF signals for a complete system view of a user’s device.

The MDO4000 series has become popular for its increasing integration of wireless interfaces including Wi-Fi, Zigbee and RFID into everyday applications. Engineers using the MDO4000 report significant gains in debugging productivity, coupled with the versatility and technical capabilities they need to tackle a wide range of test challenges.

Multi-function handheld analysers: In October 2013, Anritsu launched its MT8220T BTS Master, which is a combination of a spectrum analyser, a cable and antenna analyser and an internal power meter. “It is a multi-function handheld durable tester with all the capabilities required by network operators, sub-contractors, installers and regulatory authorities while measuring base stations. This not only improves performance by including a standard GPS receiver, but also enhances two-port dynamic range, has a faster LTE scanner, and expanded spectrum analysis capabilities,” states Madhukar Tripathi, manager, telecom segment, Anritsu India Pvt Ltd.

The MT8220T offers line sweeping, comprehensive wireless measurements, ultra-sensitive spectrum analysis and sophisticated interference tracking in a compact handheld solution. “By providing multiple testing capabilities, including comprehensive over-the-air (OTA) measurements to support remote radio heads (RRH) and MIMO, the MT8220T is well suited for the co-siting of new systems, such as LTE, with existing networks,” adds Madhukar Tripathi. The MT8220T has been specifically developed to support 4G wireless networks as well as installed 2G, 3G and WiMAX networks. It provides 20 MHz bandwidth modulation quality for LTE eNobeB testing and is equipped with a high contrast, touch screen display and backlit key panel, making it simple to use in both bright sunlight and low light conditions.

In November 2013, Scientific Mes Technik Pvt Ltd introduced handheld, USB-based spectrum analysers suitable for RF and EMC measurements manufactured by Aaronia, Germany. Based on a completely new patented method of spectrum analysis, the Aaronia Spectran spectrum analyser has a compact design and incredibly high sensitivity (HF-60100 V4 up to -170dBm/1Hz). “Finding interference sources, determining frequency and signal strength as well as evaluating most complex limits is possible through this analyser. Spectran has been designed for a very wide range of customers where portability, mobility, low weight and dimensions as well as the price is important,” says Naveen Sharma, technical engineer, Scientific Mes Technik Pvt Ltd.

SpectrumScope: In May 2013, Scientech Technologies Pvt Ltd unveiled the SpectrumScope (Scientech 852). It integrates the time and frequency domain study of various waveforms including modulation, pulse, etc, which are used in communication. “The analyser helps in detecting mobile phone signals for a frequency of 800 MHz during communication, and its level of communication can be analysed. The product is well suited for RF applications such as filters (low pass, band pass, high pass, band reject, etc) response measurement, bandwidth/frequency response measurement of amplifiers, transmission lines, transmitting antenna, filters, mixers, etc,” says Satyendra Pawar, manager, marketing, Scientech Technologies Pvt Ltd.

3 GHz spectrum analysers: GW Instek has introduced an advanced spectrum analyser called the GSP-930 in March 2012, which is still in demand in the market. It is a 3 GHz spectrum analyser, with a large screen display. High frequency stability, large screen display, light weight and compact size of the GSP-930 have become a new standard for 3 GHz spectrum analysers in the market. “The USP of this product lies in its spectrogram and topographic analysis along with sequence function that shortens the user’s programming time via a basic procedure editing function. The spectrogram analyses a signal’s fluctuation along the time-axis and the spectrum with abnormal signals and topographic display distinguishes overlapping signals and captures transient signals. It also provides 0.025 ppm frequency measurement stability,” informs Sumit Sharma, marketing manager, Good Will Instrument Co Ltd.

The GSP-930 covers the varied signal/spectrum analysis needs of RFID tag manufacturers, EMI pre-testing, antenna manufacturers, remote controllers, communication engineering, wireless products, RF components, mobile phone repair, surveillance systems, education and R&D markets, etc.

Real-time spectrum analysers (RTSA): Unveiling a high performance signal PXA N9030A spectrum analyser in February 2013, Agilent upgraded its RTSA capability to the level of its mid-performance X-series signal analyser, MXA N9020A. In addition to RTSA measurement capability, both, PXA and MXA can be used as a traditional swept-tuned spectrum analyser. Agilent X-series signal analysers can be used in fast fourier transfer (FFT) mode for vector signal analysis of complex modulated signals. These analysers are also used for more than 25 measurement applications like LTE signal analysis, WLAN signal analysis, phase noise measurement, noise figure measurement, EMC pre-compliance measurements, analogue demodulation and pulse measurement.

“The uniqueness of the existing PXA or MXA is that it can be upgraded with the RTSA option without recalibration. Agilent’s RTSAs deliver unmatched probability of intercept (POI), analysis bandwidth, sensitivity and frequency range capabilities that make them highly suitable for system developers and signal analysts to see, capture and understand highly elusive signals,” explains Asish Jain, application engineer, Agilent Technologies India Pvt Ltd.

Another unique feature of Agilent RTSA is its combination with frequency mask triggering (FMT) and Agilent 89600B VSA software. The real-time trigger can start any VSA measurement—one or many—in any measurement mode, including demodulation. “Our customers use the 89600 VSA to measure more than 75 modulation types, from custom OFDM or APSK to standard-based signals such as MIL-STD, GSM and LTE. Agilent’s 89600B VSA software is a standard tool for vector signal analysis and it runs not only on Agilent X-series signal analysers but also on Agilent oscilloscopes and logic analysers for signal analysis at various points in the PHY layer of a communication system,” says Asish Jain.

Buying tips

There are certain specifications that should be considered before buying any spectrum analyser. “Features like minimum and maximum frequency, specific frequency reference, usage of hardware and software, type of spectrum analyser, future upgrades, demodulation features, etc, should be well taken care of,” points out Satyendra Pawar.

A buyer should understand the spectrum analyser’s specifications in order to be clear about the level of performance that can be expected from it. Specifications are helpful in predicting how an analyser will perform in a specific measurement situation, as well as the accuracy of its results. “A buyer also needs to decide about the tracking generator, which is usually available as an option with basic spectrum analyser units, to meet the requirements of frequency response measurements of RF components or modules,” says Sumit Sharma.

Other specifications to be checked are resolution bandwidth (RBW), video bandwidth (VB), span, antenna support for wireless signal measurement, PC connectivity, etc. The buyer should check whether the instrument is mains-operated or battery-operated. The instrument should save space and money while cutting down power consumption. 

THE LATEST IN SPECTRUM ANALYSERS

Featured here are some of the spectrum analysers launched globally

Model: Spectran V5, Brand: Aaronia, Manufacturer: Aaronia AG

Launched in January 2013, Spectran V5 offers a combination of real-time spectrum analysis by means of a shifted poly-phase-filter that is used together with a patented measurement process with a modulated local oscillator. The device has extremely low noise signal processing – up to 170dBm/Hz.

Key features

• First real-time spectrum analyser with a real-time bandwidth of up to 200 Mhz

• Real-time streaming

• Real-time remote control (GSM, WLAN, USB)

• Patented spectrum analysis without upper lying LO (modulated LO)First analyser with ultra fast LO sweeps (µS DDS sweep)

• High resolution TFT display with a resolution of 800×480 pixels and a touch screen

• Integrated 3D motion sensor (gyro sensor) and 3D magnetic field sensor (compass and position control)

• High speed USB 2.0 (480K/s)

• Integrated lithium polymer battery (LiPo) of 8000 mAh (or 16000mAh) for up to 3(6) hours runtime

Contact details: Ph: +49-6556 93033, [email protected], www.aaronia.com

India distributor: Aimil Ltd

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Model: 3250 series, Brand: Aeroflex, Manufacturer: Aeroflex

Upgraded in December 2013, the 3250 series comprises four conventional spectrum analysers of 3, 8, 13.2 and 26.5 GHz with a choice of 3 or 8 GHz tracking generators, a digitiser with a 30 MHz bandwidth and an EMI receiver. The latest digital signal processing ensures speedy measurement, stability and accuracy.

Key features

• Low DANL and phase noise of 118 dBc/Hz at 10 kHz offset

• Pre-compliance EMI option with A and B band preselector option.

• 17.78 cm (7 inch) touch screen colour display

• LAN and GPIB remote control

• Removable hard drive

• Supported with SoftPlot creator which provides remote measurement management, as well as presentation and analysis capabilities

• Level of accuracy +/-0.5dB.

Contact details: Ph: 01438 772135, [email protected], www.aeroflex.com

India distributor: Aeroflex India

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Model: FTB-5230S, Brand: EXFO, Manufacturer: EXFO

Launched in September 2013, the FTB-5230S is an entry-level optical spectrum analyser that is ideal for a variety of field applications, including DWDM and CWDM network commissioning and troubleshooting. It offers all the typical OSA capabilities at an attractive price.

Key features

• Power and wavelength measurement

• OSNR testing according to IEC 61280-2-9 (interpolation method)

• Offline post-processing

• Features an intuitive Windows XP-based interface

• Handles a lot of power—up to 23 dBm per channel

• Ideal for modern cable operator networks

Contact details: Ph: +1800-663-3936, www.EXFO.com

India distributor: EXFO Electro Optical Engineering India Pvt Ltd

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