A near-optimum discriminator demodulator for binary FSK with wide tone spacing

Author

Stevens, M.L. ; Boroson, D.M. ; Kaufmann, J.E.

Author_Institution

MIT Lincoln Lab., Lexington, MA, USA

Volume

3

Issue

7

fYear

1993

fDate

7/1/1993 12:00:00 AM

Firstpage

227

Lastpage

229

Abstract

Optical FSK communication systems often require large tone spacings to reduce bit-error-rate (BER) degradation from laser-linewidth-induced crosstalk. Until now, discriminator detection of FSK for such wide tone spacings has fallen short of matched filter performance because of the suboptimal choice of a prefilter. A near-optimum demodulator for 240 Mb/s, three-times minimum orthogonal CPFSK (continuous-phase frequency-shift keying) has been constructed, with a measured performance that is 0.5 dB from matched filter theory at 10/sup -9/ BER. The design can be scaled to other data rates and tone spacings. The demodulator incorporates a frequency tracking loop that has good performance at low signal levels and no data-pattern dependence.<>

Keywords

demodulators; discriminators; frequency shift keying; optical communication equipment; 240 Mbits/s; BER; binary FSK; data rates; data-pattern dependence; discriminator demodulator; frequency tracking loop; laser-linewidth-induced crosstalk; matched filter performance; minimum orthogonal CPFSK; optical communication systems; signal levels; tone spacings; wide tone spacing; Bit error rate; Communication systems; Degradation; Demodulation; Frequency locked loops; Frequency measurement; Frequency shift keying; Matched filters; Optical crosstalk; Optical filters;

fLanguage

English

Journal_Title

Microwave and Guided Wave Letters, IEEE

Publisher

ieee

ISSN

1051-8207

Type

jour

DOI

10.1109/75.222784

Filename

222784