Stability analysis and design of automatic frequency control system for in vivo EPR spectroscopy

✍ Scribed by Hiroshi Hirata; Zhi-Wei Luo

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 276 KB
• Volume: 46
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1318

✦ Synopsis

Abstract

Stability analysis and design of an automatic frequency control (AFC) system for in vivo continuous‐wave EPR spectroscopy is described. The open‐loop function of the feedback control system for the AFC was derived and the stability of the feedback loop systematically examined. A stability analysis of the system is demonstrated and a systematic design procedure is proposed. The design is started from the required system specifications (phase margin, steady‐state error, and system bandwidth) and clear guidelines for designing an AFC system are given. A case study of the design is presented based on the specific needs of in vivo EPR measurements. A phase margin of 53°, a steady‐state error of 1.6%, and a system bandwidth of up to 1.8 kHz were obtained in the designed AFC system. The system specifications defined in advance are satisfied in this case study. Magn Reson Med 46:1209–1215, 2001. © 2001 Wiley‐Liss, Inc.