A Study on the Design of Digital Frequency Discriminator with 3-Channel Delay Lines

3채널 지연선을 가진 디지털주파수판별기의 설계에 관한 연구

  • Received : 2017.02.09
  • Accepted : 2017.06.09
  • Published : 2017.06.30


In this paper, we propose a DFD (Digital Frequency Discriminator) design that has better frequency discrimination and a smaller size. Electronic warfare equipment can analyze different types of radar signal such as those based on Frequency, Pulse Width, Time Of Arrival, Pulse Amplitude, Angle Of Arrival and Modulation On Pulse. In order for electronic warfare equipment to analyze radar signals with a narrow pulse width (less than 100ns), they need to have a special receiver structure called IFM (Instantaneous Frequency Measurement). The DFD (Digital Frequency Discriminator) is usually used for the IFM. Because the existing DFDs are composed of separate circuit devices, they are bulky, heavy, and expensive. To remedy these shortcomings, we use a three delay line ($1{\lambda}$, $4{\lambda}$, $16{\lambda}$) in the DFD, instead of the four delay line ($1{\lambda}$, $4{\lambda}$, $16{\lambda}$, $64{\lambda}$) generally used in the existing DFDs, and apply the microwave integrated circuit method. To enhance the frequency discrimination, we detect the pulse amplitude and perform temperature correction. The proposed DFD has a frequency discrimination error of less than 1.5MHz, affording it better performance than imported DFDs.


Electronic INTelligence;Frequency Discriminator;Integrated Circuit;Modulation;Power Amplitude


  1. L. O. Eber, H. H. Soule, "Digital Generation of Wideband IFM Waveforms", IEEE Int. Radar Conf., pp. 170-175, 1975. DOI:
  2. Wide Band System, Inc. "Digital frequency discriminator", Tehchnical Product Bulletin, No. 104, 1999.
  3. C. H. Guk, "A study on implementation of Digital Frequency Discriminator using 4 channel delay line", Ajou University, 2009.
  4. J. B. Y. Tsui, "Instantaneous frequency measurement receiver with digital processing", U. S. Patent 4633516, Dec. 30, 1986.
  5. Anaren, Inc. EW Products: Anaren IFM List, Available Form : (accessed Feb., 27, 2017)
  6. C. Y. Kim, et el, "The Quality Report on Initial Mass Product Phase for KUH-1 Surion", Defense Agency of Technology and Quality, pp. 168-191, Apr. 2014.
  7. AK Singh, Subba Rao, "Detection, Identification & Classification of Intra Pulse Modulated LPI Radar Signal using Digital Receiver", IJETAE, 2012.
  8. J. B. Y. Tsui, "Microwave Receivers With Electronic Warfare Applications", Florida, Krieger Publishing Co., pp. 183-188, 1992.
  9. Richard Wiegand, "Radar Electronic Counter -measures System Design", Artech House, 1991.
  10. James Tsui, "Microwave Receivers with Electronic Warfare Applications", John Wiley & Sons, 1986.