A CMOS 3.2-Gb/s New Scheme for Serial Link MPPM Modulator

A new efficient modulator circuit for Multi PulsePosition Modulation (MPPM) is presented. MPPM has thispotential to benefit in optical communication systems which usephoton-counting techniques for direct detection. A new schemefor modulator is designed to send 4-bit data in a symbol. Dataand clock channels are combined in a single channel. Thus, thepin count will be reduced. A novel low power, high speed slotselector circuit is proposed. The proposed MPPM modulator isdesigned in differential voltage mode to reduce the power supplynoise and power dissipation. Due to the use of a MPPM schemethe value of minimum pulse width is increased. Therefore thevalue of Inter-symbol interference is decreased. CMOS 0.18-μmtechnology and 1.8-V power supply are used for designingcircuits. Clock pulses sets on 800-MHz which is provided by a 5-stages ring oscillator VCO in a PLL block. By dividing each clockpulse to 5 time slots, the bit rate is obtained as 3.2-Gb/s.Simulations are done, using HSPICE software.

کلیدواژه ها:

Multi Pulse Position Modulation ، serial link Modulator ، MPPM Modulator ، Transmitter