Title :
A novel demodulator/detector for digital and analog signals on LMR channels
Author :
Saulnier, Gary J. ; Rafferty, William
Author_Institution :
Dept. of Electr., Comput. & Syst. Eng., Rensselaer Polytech. Inst., Troy, NY, USA
fDate :
2/1/1990 12:00:00 AM
Abstract :
The design, implementation, and performance of an all-digital demodulator/detector suitable for differential phase-shift keying (DPSK), continuous-phase frequency-shift keying (CPFSK), frequency-shift keying (FSK), and analog FM are discussed. In this modulator/detector, two detectors, one noncoherent and another differentially coherent, operate simultaneously to provide data detection and automatic frequency control (AFC). Test results indicate that the system provides improved performance over the conventional analog quadrature detector for two-period raised-cosine (2RC) CPFSK modulation in additive white Gaussian noise (AWGN) and Rayleigh fading channels. Being all-digital, the demodulator/detector is well suited for integrated circuit implementation. In addition, the system performs as well as the analog quadrature detector for analog FM voice transmissions, thereby maintaining full compatibility with analog land mobile radio (LMR) transmissions
Keywords :
demodulators; frequency modulation; frequency shift keying; mobile radio systems; phase shift keying; signal detection; telecommunication channels; AFC; AWGN; CPFSK; DPSK; FSK; Rayleigh fading channels; additive white Gaussian noise; analog FM; analog signals; automatic frequency control; continuous-phase frequency-shift keying; data detection; demodulator/detector; differential phase-shift keying; differentially coherent detector; digital signals; frequency-shift keying; integrated circuit implementation; land mobile radio channels; noncoherent detector; two period raised cosine modulation; AWGN; Automatic frequency control; Demodulation; Differential phase shift keying; Differential quadrature phase shift keying; Frequency modulation; Frequency shift keying; Land mobile radio; Phase detection; Phase frequency detector;
Journal_Title :
Vehicular Technology, IEEE Transactions on
