Wireless Systems Design

Digital, Analog, And Vector Modulation Merge

These Signal Generators Can Test And Emulate Systems Ranging From 2G And 3G To 4G, 802.11b, And Bluetooth.

Testing can be one of the most problematic steps in a design chain. When new technologies emerge, test equipment usually lags a step behind. As such, it is imperative that test equipment become more flexible. In addition, the equipment's user interfaces have to be simplified so that they aren't too hard to use. Other issues have resulted in requirements like high performance, speed, improved yield, repeatability, rapid reconfiguration, and reduced downtime.

This long list seems nearly impossible to meet. Yet the new digital RF signal generators from IFR Systems, Inc., an Aeroflex Company, work to satisfy these demands while bravely targeting the digital world. The 3410 series tackles three frequency ranges: 250 kHz to 2 GHz; 3 GHz; and 4 GHz. The instruments can be used to test and emulate second-, third-, and eventually fourth-generation (2G, 3G, and 4G) systems, as well as digital Private Mobile Radio, IEEE 802.11b Wireless Local Area Networks (WLANs), and Bluetooth. This digital RF signal-generator family is the first series to combine full digital, vector, and analog modulation in a 2U rack size.

To keep measurement errors for real-world applications to a minimum, the series offers RF level accuracy of ±0.5 dB and a low-output VSWR specification. It promises that precise and repeatable measurements can be performed on even the most sensitive analog or digital receivers. With the additional modes of operation provided, the user can optimize the signal generator for more specific measurement tasks.

Meanwhile, fast GPIB operation and a high-performance electronic attenuator combine to offer fast and reliable manufacturing test capability. Thanks to the attenuator, test-system downtime is kept to a minimum. With carrier-frequency and RF-level switching speeds below 5 ms, the instruments also have the hardware to support Universal Serial Bus (USB) 1.1 interfaces.

Through its proprietary IQ modulator design, the series achieves superb modulation characteristics covering the full frequency range of the signal generator. External IQ inputs enable the series to provide an RF modulation bandwidth of up to 100 MHz.

Typically, the adjacent-channel-power (ACP) performance is better than −68 dBc for a 3GPP FDD signal. The series' performance therefore meets the most exacting requirements of testing 3G radio receivers and power amplifiers. To reduce vector errors and guarantee low carrier leak at all operating frequencies, user-definable internal-calibration routines permit the modulator performance to be quickly optimized.

An optional dual-channel arbitrary waveform generator (ARB) permits the series to generate digitally modulated carriers with an RF modulation bandwidth of 45 MHz. The ARB operates at a high sample rate, thereby allowing smaller files to be created. This eliminates the need for selectable hardware filtering and its associated errors.

The ARB is capable of storing up to 22.5 MSamples. It comprises 60 sectors, which each are then divided into three subsectors. As a result, up to 180 files can be stored at a time. Sectors and subsectors can even merge to form larger files.

The 3410 series can be loaded with files representing different wireless RF transmission formats. Handsets from two different manufacturing lines can thus be fed into a single test bay. For example, say this is being done with a GSM and CDMA handset. The 3410 series can instantly switch back and forth between testing sets of GSM and CDMA phones. It won't incur any load-time overheard for new files.

The series offers the full range of analog modulation modes. Wide-bandwidth FM and AM are standard, encouraging the instrument's use in a variety of applications. Despite all of its capabilities, the 3410 series claims to be 35% to 50% less the size and weight of competing RF signal generators. It also introduces the first touchscreen user interface to digital RF signal generators, thereby avoiding the deeply nested menu structure (see figure). The user interface flaunts simplicity and intuitiveness.

Pricing for the 3410 series digital RF signal generators starts at $16,800. All products are available immediately. Delivery is six to eight weeks upon receipt of order.

IFR Systems, Inc.
10200 West York St., Wichita, KS 67215; (316) 522-4981, FAX: (316) 522-3022, www.ifrsys.com.

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