Oscilloscopes and spectrum analyzers are sometimes found on the same test bench. Each brings its strengths and limitations, with a scope's triggering capabilities ideal for time-domain analysis and a spectrum analyzer's sweep functions well suited for spectral displays. But what if those capabilities were combined? The answer would be the SignalVu vector signal analysis software from Tektronix, which is designed to work with the company's DPO/DSA70000 series digital phosphor oscilloscopes (DPOs). The software transforms those high-speed scopes into signal analyzers with real-time bandwidths to 20 GHz at sampling rates to 50 GSamples/s.

The SignalVu vector signal analysis software brings real-time spectrum analyzer functionality to the DPO/ DSA70000 series DPOs, specifically, adding the capabilities of the firm's RSA6100A real-time spectrum analyzer to the oscilloscopes. The combination provides the signal analysis functions of a spectrum analyzer with the triggering capabilities of a scope, especially useful when capturing and analyzing transient events. The SignalVu software works within the firm's DPO7000 and DPO/DSA70000 series digital oscilloscopes, borrowing the instrument's user interface, triggering functions, and display to show complex waveform information (see figure).

The capture bandwidth of the combination and minimum pulse-width capabilities depend upon the choice of oscilloscope, with the highest-performance model DPO/DSA72004 yielding the best performance as a signal analyzer. With SignalVu, the model DPO/DSA72004 DSO provides a maximum span of 20 GHz with minimum pulse-width detection capability of 400 ps. In contrast, a DPO7104 oscilloscope equipped with SignalVu offers a maximum span of 1 GHz and minimum pulse-width detection capability of 8 ns.

The scope/software combinations work like a spectrum analyzer, effecting Gaussian-shaped resolution-bandwidth filters in a 1, 2, 3, 5 sequence. The SignalVu-equipped scopes feature versatile display capabilities, including amplitude vs. log/linear frequency, amplitude vs. frequency over time, frequency vs. time, amplitude vs. time, and phase vs. time. Up to 5 correlated markers are available and operate across all displays. They can also optionally show tables of pulse statistics and pulse measurement results. In addition, a SignalVu software-equipped scope can also capture and show frequency-hopped signals to 20 GHz.

The displayed average noise level (DANL) with a DPO7000 series scope and SignalVu is -102 dBm through 3.5 GHz, but only slightly better through 3.5 GHz at -103 dBm with a DPO/DSA70000 series oscilloscope. Tektronix, Inc., 14200 SW Karl Braun Dr., P. O. Box 500, M/S50-317, Beaverton, OR 97077, (503) 627-7111, Internet: www.tek.com.