The editors at Evaluation Engineering approached us and asked to give them some content and feedback on a few questions on all-things Arbitrary Waveform Generators (also referred to sometimes as Function Generators). So we talked over the questions, and came up with our answers that we then sent back to EE.
Listed below are some of our answers…. and be sure to check out our waveform generator product listing for more information!
Q. Please describe in detail at least one actual customer application that was addressed by your Arbs. How was the Arb controlled? What special features were critical to the application solution? Include waveforms if possible.
A. In the Military/Aerospace test market, ZTEC’s Arbitrary Waveform Generators (AWG) are often used as the baseband modulation sources for RF generators within radar and radio test applications. For these customers, having multiple channels and comprehensive functionality is necessary to meet a variety of test requirements. For example, Raytheon Missile Test Systems uses the 4-channel ZT5212VXI AWG in the RF test configuration of its common core tester. The ZT5212VXI provides both common and independent clocking topologies. When clocked commonly, some or all of the four AWG outputs are synchronized and phase coherent for applications such as I/Q modulation. When independently clocked, the AWG outputs are completely autonomous for generating signals with different timing and sequencing. In a third clock topology, one AWG channel is used as the modulation source for the carrier supplied by a second AWG channel.
Q. What new capabilities are provided in your company’s latest Arbs? Please describe new technical features that have been developed to support these capabilities. For example, some Arbs now maintain fine frequency resolution but avoid the small periodic jitter inherent in traditional DDS implementations.
A. Although ZTEC continues to develop AWGs using the latest chip sets to provide higher digital to analog converter (DAC) sample rates and bits of resolution, we have found that supporting legacy functionality is equally important to our Military/Aerospace test customers. The high channel density and comprehensive AWG functionality of the ZT5210 series covers the majority of test requirements in the general-purpose DC to 50 MHz frequency range. In addition to baseband, IF and video test applications, the 28Vpp voltage range of the ZT5210 series allows it to address applications such as power supply and transient testing.
Q. What technological trends are driving the Arb industry? For example, several manufacturers now offer Arbs with sufficiently high sample rates to directly generate modulated RF waveforms.
A. New high-speed DACs provide up to 16-bit resolution at sample rates in excess of 1 GS/s. These devices provide the foundation for an AWG with the bandwidth and dynamic range to address modern radio and communication applications. In combination with a quadrature modulator and advanced digital signal processing, high-speed DACs can be applied to create a full-featured vector signal generator with very high modulation bandwidth. Example applications include commercial wireless standards such as Wi-Fi (IEEE 802.11), WiMAX (IEEE 802.16) and LTE, in addition to military standards such as those specified in the Joint Tactical Radio System (JTRS) initiative. Also, broad modulation bandwidth allows multi-carrier signal generation, necessary for testing receiver adjacent channel rejection. In summary, new technology will allow ZTEC to expand the applications for its AWG product line into RF test markets.