An Exact Formula for the Pull-Out Frequency of a 2nd-Order Type II Phase Lock Loop

Author

Huque, Abu-Sayeed A. ; Stensby, John L.

Author_Institution

Dept. of Electr. & Comput. Eng., Univ. of Alabama, Huntsville, AL, USA

Volume

15

Issue

12

fYear

2011

fDate

12/1/2011 12:00:00 AM

Firstpage

1384

Lastpage

1387

Abstract

The pull-out frequency of a Phase Lock Loop (PLL) quantifies the loop´s ability to remain frequency locked under abrupt changes in the reference input frequency. This parameter is very critical in many applications e.g. FSK demodulator, multicarrier, and frequency-hopping based systems. In most cases, this parameter must be determined numerically or approximated using asymptotic techniques. Either of the methods needs special knowledge, skill and tools. An exact formula is derived for computing the pull-out frequency for a 2nd-order Type II PLL that employs a triangular characteristic phase detector. With this formula, the pull-out frequency of such PLLs can easily be calculated using a current day scientific calculator.

Keywords

phase detectors; phase locked loops; FSK demodulator; PLL; Type II phase lock loop; asymptotic technique; frequency-hopping based system; multicarrier system; pull-out frequency; triangular characteristic phase detector; Detectors; Frequency shift keying; Mathematical model; Phase locked loops; Time frequency analysis; Trajectory; Voltage-controlled oscillators; Phase lock loop (PLL); phase detector (PD); phase plane; phase portrait; saddle point; separatrix; voltage controlled oscillator (VCO);

fLanguage

English

Journal_Title

Communications Letters, IEEE

Publisher

ieee

ISSN

1089-7798

Type

jour

DOI

10.1109/LCOMM.2011.101211.111902

Filename

6064855