Title :
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
fDate :
7/1/1993 12:00:00 AM
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;
Journal_Title :
Microwave and Guided Wave Letters, IEEE
