February 21, 2015: Manufacturers of spectrum analysers are focusing on feature additions and technological advancements. This will help buyers to choose the right analyser
By Samonway Duttagupta
Like everything else in the world of electronics, spectrum analysers are also undergoing tremendous technological evolution. These analysers measure how much power there is in a spectrum consisting of known and unknown signals. Every spectrum analyser has the capability to measure a range of signal frequencies. There are multiple parameters provided, which makes these measurements more accurate and enable better analysis. A closer look at the display of a spectrum analyser will reveal that the signal frequency is displayed on the horizontal axis and the amplitude is displayed on the vertical axis. A spectrum analyser looks like an oscilloscope to a casual observer. In fact, some lab instruments can function either as an oscilloscope or a spectrum analyser.
Spectrum analysers are classified into two types, swept-tuned and FFT-based, depending on the methods used to obtain the spectrum of a signal. A superheterodyne receiver is used by a swept-tuned spectrum analyser to down-convert a portion of the input signal spectrum to the centre frequency of a band-pass filter. The spectrum analyser does this by using a voltage controlled oscillator and a mixer. An FFT spectrum analyser, on the other hand, computes the discrete fourier transform (DFT), a mathematical process that transforms a waveform of the input signal into the components of its frequency spectrum.
The latest in the market
It’s been a long journey for spectrum analysers. These days they are used more for troubleshooting than just as general purpose instruments in places like laboratories. With devices getting smaller, the trend is towards portability. Models with digital and coloured displays, along with USB connectivity with a laptop or a computer, are the most sought after. In fact, the new handheld spectrum analysers are suited for users of all skill levels—even novices. Some variants have a tracking generator, GPS, power meter and DC source.
Currently, the architecture of spectrum analysers is based on reconfigurable and DSP technology, since most of the signals are processed in the digital domain. This allows a detailed online and offline analysis of the signal in the frequency domain. Spectrum analysers with touchscreens and multiple display options for day or night viewing, i.e., black or white screens, are also available. These have more markers to identify events, and support interference testing and EMF testing tools. These spectrum analysers support all communication technologies including GSM, CDMA, WCDMA, LTE, WiMAX and TDSCDMA in a single portable handheld box.
Major players compete
Most major T&M players that manufacture or distribute spectrum analysers ensure that these come with the latest features. According to sources at Anritsu India, spectrum analysers now serve as multi-purpose tools. They even come equipped with the cable antenna analyser feature, and with the use of an external power sensor, they can be turned into power meters. Spectrum analysers can also be used as interference analysers or channel scanners by mobile operators. In many cases, spectrum analysers work as signal analysers as well.
The latest spectrum analyser from Anritsu India is the MS2720T Spectrum Master. It comes with both LTE-TDD and FDD technologies including LTE-Advanced support. Besides having a touchscreen and multiple display options, this spectrum analyser supports GSM, CDMA, WiMAX, W-CDMA and LTE demodulations. AM, FM and PM modulation are also supported along with LTE over the air (OTA) and LTE signal demodulation. When asked about the key things to keep in mind while buying a spectrum analyser, Madhukar Tripathi, senior manager (channel sales and marketing), Anritsu India, says, “The application is the key factor to consider while selecting any spectrum analyser. If it is meant for field usage, it’s better to have a handheld spectrum analyser which has significant battery life and multiple display options. Frequency range, dynamic range, DANL, phase noise, OBW, masking, markers, applications, future upgradations and support of technology are some of the other key points to keep in mind. Buyers should also evaluate the cost performance ratio while selecting a spectrum analyser.”
Scientech Technologies Pvt Ltd has launched the MSA400 and MSA500 spectrum analyser series, which provide good characteristics and abundant functions in spite of being compact, lightweight and inexpensive. These spectrum analysers are said to have high end RF and reconfigurable technology, along with the DSP technology. Satish Thakare, chief technical officer, Scientech Technologies Pvt Ltd, says, “Purchasing an instrument for spectrum analysis is a major investment. So make sure that you buy one that not only meets your requirements, but can also cope up with the demands of tomorrow. From the specifications’ point of view, while choosing a spectrum analyser, it is necessary to check the data sheet detailing all the specifications. This can determine whether the instrument will be able to provide the required results.”
Tektronix India has recently launched the RSA306 spectrum analyser, which is based on the USB architecture. According to the company, this new spectrum analyser, with a list price of
Rs 258,000, sets a new price/performance benchmark in its category. It comes with features that include a 9kHz to 6.2GHz frequency range, 40MHz real time bandwidth and weighs less than a kilogram. When used with Tektronix SignalVu-PC software, it offers advanced analysis capabilities for such applications as budget constrained research and development, mobile radio network installation, interference hunting and university level lab classes. Talking a bit more about this spectrum analyser, Naresh Narasimhan, country marketing manager, Tektronix India, says, “As with nearly all areas of electronics design and testing, the requirements for RF and microwave tests are changing rapidly, leading to the need for new instrumentation approaches. The introduction of RSA306 demonstrates the fact that Tektronix India is moving aggressively towards addressing these changing requirements across multiple market segments with the help of innovative, industry leading test and measurement solutions.”
The latest spectrum analyser brought into the market by another leading player, MetroQ, is the GA4032-TG model. It comes with a 9kHz to 1.5GHz frequency range, an ageing rate of 1ppm/year, a phase noise of -90dBc/Hz at 10kHz and a DANL of 140 dBm. This device also comes with a wide 21.6cm screen. Manish Kwatra, managing director, MetroQ, says, “Most of the latest spectrum analysers in the market come with USB connectivity. But we have a model with a full featured screen at a lower price than the USB versions. We have a very good pricing for our full featured spectrum analyser and, at the same time, it adheres to international quality standards. Our new GA4032-TG model has an MRP of around Rs 120,000.”
Anritsu India’s MS2720T Spectrum Master
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Frequency ranges: 9kHz to 9GHz, 13GHz, 20GHz, 32GHz and 43GHz
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Internal atomic clock option for handheld frequency accuracy
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Measurements: Occupied
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bandwidth, channel power, ACPR, C/I, emission mask, field strength
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3G and 4G measurement options for LTE, CDMA, W-CDMA, WiMAX, GSM and TD-SCDMA
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Interference analyser: Spectrogram, signal strength, RSSI, mapping
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Dynamic range: >106dB in 1Hz RBW @ 2.4GHz
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DANL: –160dBm in 1Hz RBW @ 1GHz preamp On
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Phase noise: –104dBc/Hz @ 10kHz offset at 1GHz
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1Hz to 10MHz resolution bandwidth (RBW)
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Tracking generator up to 20GHz
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Scientech Technologies’ MSA400 and MSA500 series of spectrum analysers
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Compact and lightweight: 1.8 kg
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150 minutes of battery operation
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Accurate frequency measurement by PLL synthesiser
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Average noise level -117dBm
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Competitive functions
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Easy operation by AUTO mode
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Hard copy of screen image
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Measures electric field strength from 300MHz to 6.2GHz
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Abundant options like PC software, logging software, VSWR bridge; dipole antenna, magnetic field probe, printer, frequency counter, etc.
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Tektronix India’s RSA306
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Full featured spectrum analysis capability with Tektronix SignalVu-PC software, 27 spectrum and signal analysis measurements as standard
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Options for mapping, modulation analysis, standards support, pulse measurements and frequency setting
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Real time spectrum/spectrogram display to minimise time spent on transient and interference hunting
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Application programming interface (API) included for Microsoft Windows environments
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MATLAB instrument driver for use with instrument control toolbox
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Streaming capture to record events of long durations
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MetroQ’s GA4032-TG
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21.6cm widescreen display
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Frequency: 9kHz to 1.5GHz
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Ageing rate: 1ppm/year
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Phase nose: -90dBc/Hz at 10kHz
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DANL: 140dBm
