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I/Q modulation generator provides 300MHz memory clock

Posted: 23 Mar 2006 ?? ?Print Version ?Bookmark and Share

Keywords:R&S AFQ100A? I/Q modulation generator? Rohde & Schwarz?

Rohde & Schwarz announced the R&S AFQ100A I/Q modulation generator, which provides a memory clock of 300MHz combined with a memory depth of up to 1 Gsample. The product is suitable in R&D and production for generating complex digital modulation signals. It is available with an output memory of 256Msamples or 1Gsample; in addition to analog outputs, it can also be fitted with a digital I/Q output.

According to the company, modern communications technologies use a wide variety of digital modulation methods. To achieve higher data rates, new modulation methods are continuously being developed. As a result, a flexible modulation source that generates these complex signals is required for tests in R&D and production. The product has a variable memory clock rate of 1kHz to 300MHz and large memory depth of up to 1Gsample. It allows I/Q signals with an RF bandwidth of up to 200MHz to be generated.

The R&S AFQ100A comes with an unbalanced analog output that has a level that can be set between 0 to 1.5V and a balanced output that has a level varying between 0 and 3V. A bias voltage of -2.5V to 2.5V may additionally be superimposed on the signal at the balanced output. Plus, the device can be equipped with digital outputs which offer 16bit resolution and support a maximum data rate of up to 300MHz.

The product achieves signal quality at an S/N ratio of 83dBc (typ) and a frequency response of 0.05dB (typ) across the entire bandwidth. The generator also features various trigger functions; plus the output signal can be adjusted in various ways to compensate for impairments. If necessary, the internal equalizer changes the output signal in real time, compensating for external frequency responses of I/Q modulators.

As an independent baseband source, the device provides the DUT with I/Q signals directly via an analog or digital output. In conjunction with a vector signal generator, the R&S AFQ100A also generates the appropriate RF signals. The signal data can be output from the memory at a user-adjustable clock rate. Users can select a very small clock rate to achieve maximum signal duration. Since there is no link to a specific part of the memory, the signal sequence length can be user-defined. The multi-segment waveform function allows fast switchover between the different signal sequences stored in the memory. In addition, the multi-segment waveform function allows applications with baseband hopping to be performed.

The signals are generated on a PC using the R&S WinIQSIM2 software supplied with the R&S AFQ100A, or directly via the conventional MATLAB PC software. The product can be controlled via general-purpose interface bus, USB and LAN (Gigabit Ethernet) or operated as a standalone instrument by using the integrated video, mouse and keyboard interface.

The R&S AFQ100A I/Q modulation generator is now available from Rohde & Schwarz.

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