It is a challenge to generate WiMedia signals capable of testing the wide variety of UWB device types. This testing must not only establish conformance with protocol definitions, but must establish operating margins. Currently, there are two ways to generate WiMedia signals. Both of these methods have their own sets of advantages and disadvantages, providing the designer with options that can be applied for different test requirements.

The first method is shown in the upper portion of Figure 2. This first method provides all the advantages of an arbitrary waveform generator, such as creating real-world signals, including distortions and impairments, and frequency hopping at RF (which is mandatory as per WiMedia specifications, and involves the use of costly and complex arrangements such as external frequency hoppers). Though the second method — which uses a dedicated UWB chipset to feed the device under test (DUT), as shown in the lower half of Figure 2 — provides the ability to band hop signals, it does not offer the functional flexibility and RF agility provided by an AWG. It is, therefore, desirable to develop a hybrid method for generating WiMedia-based UWB waveforms having the power of the first method, while retaining the simplicity of the second method. The implementation for a unique method having these characteristics is outlined in the following discussion.

The synthesis of signals with bandwidths exceeding 1.5 GHz at carrier frequencies up to 10 GHz exceeds the capability of traditional vector signal generation architectures used in wireless communication testing. The necessary modulation and baseband bandwidths, the frequency-hopping nature of the UWB-WiMedia signals and the influence of any amplitude, timing, and frequency response misalignments of the I and Q components of the signal requires additional effort to achieve the signal quality needed for UWB-WiMedia signals. In addition to the following descriptions for potential architectures for UWB signal generation, Table 2 lists several additional details on the AWG requirements for different configurations.

Previous 1 2 3 4 Next