Improvement of Amplitude-Shift-Keying Signal Quality by Employing an Effective Spectrum Equalization Method in a Combined FSK/ASK Modulation Scheme

A simple, economical and applicable spectrum equalization method is implemented by employing a reshaping filter in the combined frequency-shift-keying/amplitude-shift-keying modulation scheme to improve the quality of amplitude-shift-keying optical signal. The 3-dB improvement for eye diagram height is experimentally demonstrated.