Amplitude modulation and the first-order phase-locked loop

PB Kenington, JP McGeehan, DJ Edwards

Research output: Contribution to journalArticle (Academic Journal)peer-review

2 Citations (Scopus)


The behaviour of a first-order phase-locked loop is critically examined under conditions where it is tracking a carrier corrupted by discontinuous (square-wave) amplitude modulation. The transient response of the system is first derived for the simple case of a PLL without time delay, and a comparison is made with a series of practical results obtained from a first-order loop. The agreement between the predicted response and that observed in practice is found to be extremely good. The theoretical behaviour of the loop is further analysed for the case of a system incorporating time delay. It is shown that such delay is detrimental to the tracking performance of the loop, when it is necessary to track a carrier modulated in the manner outlined above
Translated title of the contributionAmplitude modulation and the first-order phase-locked loop
Original languageEnglish
Pages (from-to)17 - 24
Number of pages8
JournalIEE Proceedings I - Communications, Speech and Vision
Issue number1
Publication statusPublished - Feb 1990

Bibliographical note

Publisher: Institute of Electrical Engineers (IEE)
Rose publication type: Journal article


  • amplitude modulation
  • phase-locked loops
  • radio receivers
  • satellite ground stations
  • radar and radionavigation
  • modulation


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