R&S^®ZVB Vector Network Analyzers

Balanced measurements

Using its virtual differential measurement mode, the R&S^®ZVB characterizes balanced DUTs with one or two balanced ports quickly and accurately. The balanced DUT is directly connected to the analyzer test ports. Its unbalanced S-parameters are measured, and the mixed-mode S-parameters are calculated from these values. The numerous traces and diagrams offered by the R&S^®ZVB provide full characterization of the DUT and straightforward display of all measurement quantities. No complicated settings are needed on the part of the user. Convenient marker search and analysis functions facilitate result evaluation especially in the case of filter measurements, for example by determining the filter parameters such as bandwidth, ripple, quality factor, etc.

Display of mixed-mode S-parameters of a SAW filter

Mixer and harmonics measurements

Straightforward dialog menus help you configure standard mixer measurements quickly and easily. Conversion loss and absolute powers can be measured, provided that one of the RF, LO, or IF system frequencies is constant (as is the case when mixing a signal to a fixed IF, for example). When using a four-port analyzer, no external generator is required, as the instrument itself contains two generators. This not only reduces instrumentation effort, but also considerably boosts measurement speed, since no time is needed for commands applied via IEC/IEEE bus or LAN. The analyzer sweep time corresponds to the time required by a normal frequency sweep.

Based on menu-guided power calibration, even wave quantities (absolute powers) can be measured accurately.

Harmonics of any order can be displayed versus frequency or power.

Dialog for configuring a mixer measurement

Time domain measurements

This option allows complex S-parameters to be transformed into the time domain, making it possible to display discontinuities versus the time delay or the electrical/mechanical length of the device under test. The impulse response represents the reflection factor of a discontinuity (i.e. the peak of the "reflected" signal versus runtime or electrical/mechanical length). In addition, the DUT's step response can be calculated in order to display impedance versus length, for example.

You can conveniently select a bandpass characteristic or a lowpass characteristic – the lowpass characteristic has, among other things, the effect of doubling the resolution.

By setting a window in the time domain (gating function), you can display S-parameters for a specific section of the DUT. When measuring a cable that contains several discontinuities, for example, it is thus possible to separately determine the reflection S11 of a particularly slight discontinuity.

Five filter types are available for optimizing peak width/resolution and side lobe suppression.

Enhanced resolution with linear prediction function

With conventional TDR methods, the resolution, i.e. the width of reflected-signal peaks and the rise time of step responses, is limited by the network analyzer's frequency range. The R&S^®ZVB does away with this limitation. Its linear prediction function expands the frequency spectrum by way of computation. Using a prediction factor of three, for example, will reduce the peak width or the rise time by a factor of three – yielding a resolution corresponding to that of a network analyzer with three times the frequency range.

Using this function, you can analyze considerably finer structures than was previously possible due to the limitation to the analyzer's actual frequency range. This function also allows narrowband and frequency-limited DUTs to be measured with higher accuracy.

Time domain characteristics of a narrowband DUT limited to 1 GHz bandwidth
Red trace: unresolved peak; DUT width corresponding to 1 GHz sweep span
Blue trace: enhanced resolution using linear prediction function