Microwave Journal
www.microwavejournal.com/articles/32377-arbitrary-waveform-generator-accurately-simulates-fast-changing-real-world-signals

Arbitrary Waveform Generator Accurately Simulates Fast-Changing Real-World Signals

June 12, 2019

Complex systems operating in complex environments - radar, electronic warfare (EW), advanced wireless communication systems and hardware-in-the-loop test simulation - require the ability to put the system under development through extensive stress testing, simulating real-world environments. Yet how can engineers cycle through signal tests quickly enough to accurately recreate chaotic and unpredictable real-world signals?

Figure 1

Figure 1 With 50 GSPS sampling, 20 GHz frequency range and up to 32 GS memory, the Tektronix AWG70001B AWG generates complex waveforms for real-world radar, EW and communications testing.

If a waveform can be defined or captured, chances are the new Tektronix AWG70000B series of arbitrary waveform generators (AWG) can generate the signal (see Figure 1). With waveform sampling rates to 50 GSPS, 10-bit vertical resolution and −80 dBc spurious free dynamic range, these instruments have the precision and resolution for the most advanced radar and EW applications.

Superior digital-to-analog converter performance is not enough to generate realistic signals for testing modern radar, EW and communications systems. Dynamically managing an RF test environment requires keeping track of thousands of individual waveforms, then altering sequence steps as the tests progress. With some commercially available AWGs, the ability to change test sequences is limited to just 256 sequence steps, accessible through an 8-bit pattern jump connector. The AWG70000B addresses this limitation with its new Streaming Waveform ID capability, adding a dedicated Ethernet port to the rear panel of the instrument (see Figure 2). This port allows for direct access to the sequencer hardware using UDP-formatted packets and provides immediate access to up to 16,383 sequence steps in system memory.

Figure 2

Figure 2 The Waveform Streaming ID function gives immediate access to up to 16,383 sequence steps from system memory, enabled by a dedicated Ethernet port on the back of the AWG.

By selecting and combining different sequence steps, users can quickly create a variety of complex radar pulses, EW, electronic countermeasures (ECM) waveforms and modulated communications signals. Particularly when simulating ECM, dynamic signal scenarios work in tandem with the deep waveform memory, enabling the AWG to stream longer strings of continuous radar pulses. For such applications, the AWG70000B can be equipped with up to 32 GS of waveform memory, enabling users to play 640 ms of data at 50 GSPS. The Streaming Waveform ID function is also useful for wireless communications research. In these applications, users can change modulation on the fly to simulate Doppler radar, building obstructions and other obstacles, which can help improve OFDM signal durability in real-world deployments.

Generating Complex Waveforms

Generating complex waveforms starts by using the AWG70000B’s sequencer to string together multiple individual waveforms. The sequencer allows for branching and looping, which speeds waveform generation, reduces memory usage and does not require external program control. The improved waveform output capability with the sequencer enables running a series of waveforms automatically and supports complex pattern jumping, flag outputs, sub-sequences and batch compilation. With Streaming Waveform ID, users dynamically control the AWG70000B’s sequencer actions by streaming jump instructions directly to the sequencer in real time, via the new Ethernet Streaming ID connector. Streaming jump instructions directly to the sequencer greatly enhances the speed at which jumps are performed to better simulate the real world.

Figure 3

Figure 3 Radar pulses created with the AWG70000B with the radar plug-in.

Creating waveforms happens in several ways. Tektronix offers a growing library of plug-ins to aid creating waveforms optimized for RF, radar, optical and other applications (see Figure 3). The AWG70000B also supports third-party solutions such as MATLAB and Excel, and signals captured using oscilloscopes or spectrum analyzers can be edited and loaded into the AWG70000B for play back. The AWG70000B also works with SourceXpress PC software, which enables users to create signals anywhere and control multiple AWGs.

Options

The AWG70000B is available in one or two channel configurations. The single-channel AWG70001B offers the full 50 GSPS sampling rate and a maximum output frequency of 20 GHz. The standard available waveform memory is 2 GS, with the option to increase it to 32 GS. The dual-channel AWG70002B samples at 25 GSPS per channel and a maximum output frequency of 10 GHz per channel. The standard waveform memory is also 2 GS per channel, with the option to increase memory up to 16 GS per channel.

For MIMO and more advanced signal generation needs, as many as four of the AWG70001B or AWG70002B AWGs can be synchronized. Testing phased array radar and generating I/Q signals for optical transmission are two examples of applications that require more signal sources. Output signal phase can be maintained within a single clock cycle and tightly controlled within a ±10.8 degree range, and skew can be adjusted by ±10 ps across multiple AWGs.

Windows 10 Support

The AWG70000B series now includes support for the Microsoft Windows 10 operating system to meet IT security mandates for instrument operation in government agencies and corporate IT departments.

When it comes to advanced signal generation, the AWG70000B series combines high resolution and precise signal fidelity with comprehensive PC software. With Streaming Waveform ID, deep memory and support for Windows 10, the AWG70000B provides the precision and resolution needed for testing phased array radar, EW, ECM and other military electronic systems and software-defined radios, as well as high speed and high frequency communciations systems. The AWG70000B series is available globally with prices starting at $83,600.

Tektronix Inc.
Beaverton, Ore.
www.tektronix.com