Network Analyzers measure group delay over long distances.

Press Release Summary:

Series ZVA and ZVT network analyzers are available with ZVA-K10 software option that enables them to measure group delay and phase linearity on satellite links. In test setup user connects one network analyzer to transmit port and one to receive port; the 2 analyzers communicate and synchronize the test sequence between each other via LAN connection. A 2-tone signal is used to calculate the group delay and relative phase of device-under-test's transfer function.

Original Press Release:

Network Analyzers from Rohde & Schwarz Use New Method to Measure Group Delay Over Long Distances

Munich - Rohde & Schwarz has developed a unique method that accurately measures group delay and phase linearity on satellite links. With the new R&S ZVA-K10 software option, users can perform measurements using two network analyzers located at separate sites. In open-area tests, for example, the analyzers can bridge long distances between a transmitter and a receiver. Unlike with all other test methods on the market, network analyzers do not need to access the local oscillator when measuring frequency-converting DUTs. With the new method, Rohde & Schwarz has solved a persistent and difficult problem in satellite T&M. The new R&S ZVA-K10 option is available for the R&S ZVA and R&S ZVT high-end network analyzers.

Precise measurement of group delay and phase linearity is vital in order to determine satellite communications quality. Today's ever-increasing transmission rates also place more stringent demands on transmission quality. Key parameters for transmission quality are group delay and phase linearity within the useful band. With the test setup from Rohde & Schwarz, users can perform accurate measurements on up- and downconverters used in satellite communications, as well as on complete transmission systems or individual components such as transmitters, receivers or mixers.

The conventional approach to measuring group delay and phase linearity is to connect the input and output of a DUT to a network analyzer via RF cables. However, if the input and output are located far apart, cable losses will degrade the measurement's signal-to-noise ratio. In open-area measurements, cables need to bridge distances of several hundred meters. In addition to causing high loss, cables also introduce significant phase errors even if they are just slightly moved.

The new test method from Rohde & Schwarz provides reliable results. In a test setup with the R&S ZVA-K10 software option, the user connects one network analyzer to the transmit port and one to the receive port. The two network analyzers communicate with each other and synchronize the test sequence between each other via a LAN connection.

Conventional test methods need to access the local oscillator in order to determine group delay and phase shift. This is often not possible, however, because the local oscillator is integrated in the DUT. To solve this problem, Rohde & Schwarz developed a two-tone method. The R&S ZVA stimulates the DUT with a two-tone signal and measures the phase difference between the two carriers at the input and the output. From the phase difference, the R&S ZVA calculates the group delay and the relative phase of the DUT's transfer function. Any changes in the local oscillator's frequency and phase have an identical effect on both carriers and are eliminated by the difference measurement; they do not, therefore, affect measurement accuracy. Users are provided with accurate results.

The R&S ZVA-K10 software option is now available from Rohde & Schwarz. For detailed information about the high-end network analyzer R&S ZVA go to

Press contacts:
Europe (headquarters): Monika Roth, Phone: +49 89 4129 12232, E-mail:

North America: Chris Petrole, Phone: +1 410 910 7836, E-mail:

Contacts for readers:

Customer Support Europe, Africa, Middle East: Phone: +49 89 4129 12345


Customer Support North America: Phone: +1 888 837 8772, E-mail:

Customer Support Latin America: Phone: +1 410 910 7988, E-mail:

Customer Support Asia: Phone: +65 65130 488, E-mail:

Rohde & Schwarz

Rohde & Schwarz is an independent group of companies specializing in electronics. It is a leading supplier of solutions in the fields of test and measurement, broadcasting, radiomonitoring and radiolocation, as well as secure communications. Established more than 75 years ago, Rohde & Schwarz has a global presence and a dedicated service network in over 70 countries. It has approx. 7400 employees and achieved a net revenue of Euros1.3 billion (US$ 1.6 billion) in fiscal year 2009/2010 (July 2009 to June 2010). Company headquarters are in Munich, Germany.

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