Model 8800 Frequency Response Analyzer Receives Patent for Digital Technology

Venable Instruments Receives Patent for Digital Frequency Response Analyzer Technology

Only instrument that can measure the plant of a digitally-controlled

feedback loop directly and accurately


AUSTIN, Tex. – March 15, 2017 — Venable Instruments, a leading provider of stability testing and measurement instruments for power supply design, has received a patent for its Digital Frequency Response Analyzer (DFRA™) technology.


The new patent, US 9,562,951, is titled, “DIGITAL FREQUENCY RESPONSE ANALYSIS SYSTEM AND METHOD USEFUL FOR POWER SUPPLIES.” The invention is a collaboration from Venable’s experienced engineering team, and the technology is incorporated into the Company’s Model 8800 Series of DFRAs. The Model 8800 Series DFRAs are the only instruments commercially available that can measure the plant of a digitally-controlled feedback loop directly and accurately.


The timing of the patent is pivotal, as forces driving digital adoption continue to accelerate.  Application-critical environments demand data accuracy, and until now, existing digital loop measurement techniques could only provide an estimated prediction, not a direct plant measurement.


The analyzer utilizes a digital “Sync” signal to provide synchronization between analog and digital hardware. The Model 8800 performs simultaneous analysis on both analog input channels and the digital target processor, reliably capturing all data. The Model 8800 Series offers a broad and growing range of supported processors, and is available with analog frequencies from 10µHz to 5MHz, 20MHz and 40MHz options. Flexible by design, the Model 8800 Series digital interface can be disabled, via software, to use the analyzer in a standard two-channel, analog-only configuration.

Digital Feedback Loop

Digitally-Controlled Feedback Loop

The digital interface provides a direct connection to the Device Under Test (DUT). Common to all Venable digital and analog frequency response analyzers, the Model 8800 Series is a modular design to reduce costs while also providing a scalable solution for frequency and channel upgrades. Scalability provides a cost-effective upgrade path to more functionality, while preserving the initial instrument investment.  All Venable frequency response analyzers are bundled with the Company’s proven Stability Analysis™ software, an elevated, feature-rich version of the renowned K-Factor Technique also created by Venable.  All Venable frequency response analyzers can be calibrated to the ISO-Certified Z540.1 Standard.


Venable Instruments, including the authors of this patent, will be demonstrating the Model 8840 Series Digital Frequency Response Analyzer and other power supply design solutions at the Applied Power Electronics Conference (APEC), March 26-30, 2017, Tampa, Florida, Booth 1310.


The Model 8800 Series of Digital Frequency Response Analyzers are shipping now. Contact Venable at, (512) 949-3144, toll-free in US (800)262-2522 or go to  for more information.


About Venable Instruments

Founded in 1979, Venable Instruments is a recognized leader in stability analysis systems and services, specializing in analog and digital frequency response analyzer-based systems. Design engineers in aerospace, defense, automotive, power, computer technology, academia and virtually any innovative organization designing application-critical power electronics rely on Venable’s robust analyzers for measurement, analysis, synthesis, modeling and design of feedback loops. Venable’s wide range of products also offers solutions for impedance measurement of power supplies and components (RLC).



Donald Woodard

Venable Instruments


For more information contact 800.262.2522 or 512.949.3100