Rapid High-Frequency Measurements of Electrical Circuits by Using Frequency Mixer and Pseudo-Random Sequences

• Main Authors: T. Roinila, R. Luhtala, T. Salpavaara, J. Verho, T. Messo, M. Vilkko
• Format: Article
• Language: English
• Published: Norwegian Society of Automatic Control 2016-04-01
• Series: Modeling, Identification and Control
• Subjects: Identification; Frequency measurements; Modeling; Excitation design
• Online Access: http://www.mic-journal.no/PDF/2016/MIC-2016-2-3.pdf
• ISSN: 0332-7353; 1890-1328

Frequency-response measurements at high frequencies have been shown to provide a valuable design tool in various fields of electronics. These measurements are often challenging when using most commercially available measurement tools due to their relatively low maximum sampling frequency and long measurement time. This effectively prevents frequency-response-based low-cost applications where fast and reliable measurements are required. This paper proposes the use of a combined frequency mixer applied with pseudo-random sequences. In this method, the applied pseudo-random excitation is upconverted to high frequencies by the mixer, and once injected into the device being tested, the system response is downconverted to lower frequencies. The method provides a low-cost solution that can be applied for rapid high-frequency measurements by using only modest data-acquisition tools. Experimental results based on a high-frequency resonator are presented and used to demonstrate the effectiveness of the proposed methods.