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New High End Spectrum and Signal Analyzer

November 5, 2011
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The new R&S FSW signal and spectrum analyzer has been developed to meet demanding customer requirements. Designed to set standards in RF performance and usability, the analyzer has a wide analysis bandwidth and straightforward, intuitive operation that makes it particularly suitable for use in the aerospace and defense (A&D) sector and for developers of future communications systems.


The new, innovative internal architecture of the analyzer is claimed to deliver RF performance not previously possible in high end analyzers. For example, the first intermediate frequency (IF) of about 9 GHz allows image suppression up to 8 GHz without a YIG preselector. Traditionally, this frequency limit has been 3 to 4 GHz. The advantage is a very flat, stable, reproducible frequency response up to 8 GHz, which results in an absolute level accuracy of < 0.4 dB. This is especially significant for wireless applications in the 5 GHz bands, e.g. WLAN IEEE 802.11a/n/ac.

In addition, the R&S FSW uses different signal paths depending on the RF frequency. From 2 Hz to 30 or 40 MHz (depending on the resolution bandwidth used), the input signal is directly digitized by the 200 MHz, 16 bit A/D converter. Excellent sensitivity and a dynamic range down to the lowest frequency are the result.

The frequency range up to 1 GHz uses 1.31 GHz as the first IF. Due to the low first IF, a low frequency local oscillator and low frequency mixer with a very high dynamic range can be used. This results in a high third order intercept point of 30 dBm and very low phase noise. This makes the analyzer very powerful for this frequency band, which is of interest for many applications, such as professional and private mobile communications.

MICROWAVE FREQUENCIES

In the frequency range up to 8 GHz or the microwave range up to 26.5 GHz, where a YIG pre-selector is used, the R&S FSW offers a very high dynamic range up to microwave frequencies. At 20 GHz, with preamplifier, for example, the result is a displayed average noise level (DANL) of -166 dBm (1 Hz). With noise compensation, it nearly reaches the thermal noise floor with -173 dBm (1 Hz). The instrument not only delivers very good sensitivity, it also handles high signal levels. For example, an adjacent channel leakage ratio (ACLR) of -88 dB for a 3G signal at 2 GHz says a lot about its dynamic range. This is especially important for manufacturers of mobile radio
base stations.

The R&S FSW is believed to be the first analyzer to provide switched lowpass and bandpass filters in the RF frequency range for the measurement of harmonics. This is the most critical range, i.e. when measuring harmonics of mobile radio base stations or handsets. A second harmonic intercept of 70 dBm eliminates the need for external filters with switch matrixes. The R&S FSW reduces cost and the customer no longer has to calibrate the setup with external signal paths.

Developers of oscillators, synthesizers and transmit systems benefit from the analyzer's excellent dynamic range when performing phase noise measurements. Thanks to the in-house YIG technology and the custom R&S synthesizer ASICs, the R&S FSW achieves a phase noise of -137 dBc (1 Hz) at 10 kHz offset from the carrier (for a 1 GHz carrier). With this performance, the instrument detects signals close to the carrier that previously could not be seen with a spectrum analyzer. It also delivers a previously unattainable dynamic range for adjacent channel power measurements in narrow bandwidth applications such as public mobile radio.

WIDEBAND AND MULTI-STANDARD APPLICATIONS

The R&S FSW offers up to 160 MHz analysis bandwidth for measuring wideband-modulated signals such as future 4G, WLAN IEEE 802.11ac and frequency-agile signals. Furthermore, the RF signal path can handle up to 500 MHz bandwidth in anticipation of future wider bandwidth requirements. The 500 MHz bandwidth is available at the IF output and can be used to connect an R&S RTO scope for wideband analysis, for example.

When designing the R&S FSW, the engineers introduced a new feature for signal analyzers. Currently, signal and spectrum analyzers measure different standards (GSM, CDMA, W-CDMA and LTE) separately. The new instrument takes analysis to the next level, providing the capability to measure multiple standards simultaneously with the multi-standard radio analyzer (MSRA) function. This feature is interesting both for the design and production of multi-standard base stations as well as for testing interactions between radar signals and mobile radio communications.

Figure 1 A Flat menu structure and block diagrams make measurement setup an easy task.

EASE OF USE

As well as the RF performance it offers and the fact that it covers future wideband application requirements, the R&S FSW also provides a new level of usability and ease of operation. Similar to a smartphone, it features a touchscreen user interface and a flat menu structure (shown in Figure 1) so deep menu trees are no longer needed. The result is a straightforward, clear
presentation.

Figure 2 Multiple measurements, such as spectrum analysis and special analysis of pulsed signals, can be displayed at the same time.

The analyzer displays various measurements simultaneously in separate windows on its large 12.1-inch screen, which greatly facilitates result interpretation (see Figure 2). Users can quickly switch between different setups because settings are kept in the memory and do not have to be reloaded from disk. In addition to practically delay-free switching between instrument setups, the R&S FSW also features outstanding measurement speed such as 1000 sweeps/s in remote operation.

Currently, three models of the R&S FSW are available, covering the frequency ranges of 2 Hz to 8/13.6/26.5 GHz. With an initial focus on A&D applications, the R&S FSW comes with application firmware for measuring phase noise, noise figure and gain and pulsed signals. The most frequently requested measurement applications for mobile radio, such as analysis of LTE and 3G signals, are also available. Other measurement applications and frequency enhancements will be introduced step-by-step to cover the full application range of the well-known R&S FSU/Q spectrum and signal analyzers.

Rohde & Schwarz
Munich, Germany
+49 89 4129 12345
www.rohde-schwarz.com

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