Sideband false-lock performance of squaring, fourth-power, and quadriphase Costas loops for NRZ data signals
Abstract
This paper derives the sideband false-lock margins of the short squaring, short fourth-power, long fourth-power, and quadriphase Costas loops for NRZ synchronous data streams. The false-lock margins in the short fourth-power and quadriphase Costas loops are found to be 5-10 dB worse than those in the short squaring and biphase Costas loops. The extremely low false-lock margins of 3 and 4 dB in the short fourth-power loop at typical design values of the prefourth-power bandpass filter bandwidth were verified by experimental results. Also described are several experimentally tested methods for false-lock prevention.
- Publication:
-
IEEE Transactions on Communications
- Pub Date:
- August 1980
- Bibcode:
- 1980ITCom..28.1335K
- Keywords:
-
- Computerized Simulation;
- Data Transmission;
- Feedback Control;
- Performance Prediction;
- Phase Shift Keying;
- Sidebands;
- Bit Synchronization;
- Error Signals;
- Phase Locked Systems;
- Power Spectra;
- Communications and Radar