Test & measurement
Figure 1: The M5i.6357-x16 PCIe card with two differential channels and 10 GS/s output rate
A 36
rbitrary waveform generators, or AWGs, are signal sources that can produce waveforms limited only by their sampling rate and bandwidth. Spectrum’s new M5i.63xx series AWG family extends the frequency
range of waveforms that PC based instruments can produce. The products feature sampling rates up to 10 Giga samples per second (GS/s) and output bandwidths up to 3.5 Gigahertz (GHz). They come packaged as either PCIe cards (M5i.63xx series) that plug directly into two PCIe slots of a suitable PC or as stand-alone NETBOX instruments (DN2.63x series) that connect directly to a PC or company network via Ethernet. The M5i.6357-x16 PCIe version is shown in Figure 1.
The AWGs are perfect for generating high-frequency signals up to their full bandwidth, with up to 100 picoseconds (ps) time resolution and an amplitude resolution of 16 bit. As such, they present test engineers, scientists, and designers with a cost-effective way to produce arbitrary waveforms up to microwave frequencies, with high purity and low distortion. The AWGs also feature massive onboard waveform memories of up to 8 Giga Samples per channel (16 GigaBytes), producing an 800 ms record length at 10 GS/s. If necessary, the PCIe cards can produce even longer waveforms by streaming data directly over the bus from CPUs or GPUs at transfer rates up to 10 Gigabytes per second (5 GS/s). Designed for applications requiring automated and/or remote waveform generation, the AWGs are fully programmable using today’s most popular programming languages. Spectrum’s graphical user interface (GUI), SBench6,
By Oliver Rovini and Arthur Pini, Spectrum Instrumentation
is also available for local interactive control, waveform creation, and display, and it includes various useful data import, export, and analysis tools. Let’s look at some typical applications of these products.
MEASURING RF FILTER CHARACTERISTICS Measuring the frequency response of a filter requires a signal source and a measurement instrument like a digitizer, which should both have bandwidths greater than the filter bandwidth. Consider measuring the frequency response of a 50 MHz bandpass filter with a center frequency of 425 MHz. Possible broadband signal sources for frequency response testing include swept frequency sinewave, impulse functions, and white noise. The swept sinewave offers the highest dynamic
APPLICATIONS FOR ULTRAFAST ARBITRARY WAVEFORM GENERATORS
range of measurements and is most commonly used. The test requires a signal source to generate the input signal to the filter. In this example, an M5i.6350-x16 (10 GS/s, 2.5 GHz, 16 bit, one channel) is used to generate a linear sine sweep. A digitizer model M5i.3360-x16 (10 GS/s, 4.7 GHz, 12 bit, one channel) acquires the filter output, and the frequency response is measured. Each instrument is controlled, in this case, by Spectrum Instrumentation’s SBench6 GUI. SBench6 incorporates a function generator that can create complex waveforms using equations. The equation used in this example for a swept sinewave is shown in Figure 2.
The SBench6 function generator editor supports ten mathematical operators, eleven functions, four
May 2025 Instrumentation Monthly
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76
