Pulse-position and pulse-amplitude modulation interface for serial data link applications

A serial communication link based on pulse-amplitude modulation combined with pulse-position modulation is presented in this paper. The timing problem that occurs when combining the pulse-position modulation and the pulse-amplitude modulation has been resolved using the proposed technique by applying the AM modulation to the data signal and the clock signal. Using the proposed architecture, the reception of the pulse-position modulated bits will not be affected by the combining of the amplitude modulation and the number of the amplitude levels can be increased as many as possible. The PPM technique and the AM technique are combined in so as to increase the total number of the transmitted bits without affecting the transmitted data signal bandwidth. A 5 bits 4 GB/s PAM-PPM link has been designed and simulated in 130 nm CMOS technology using 800 MHz input clock signal. The simulation results indicate that combining PAM technique with PPM technique increases the number of transmitted bits per clock cycle of the data signal without altering the bandwidth. The simulated power consumption of the designed transceiver is less than 90mW.