A dual slope based pulse position modulation circuit for sub-GHz IR-UWB systems

A pulse position modulation circuit for IR-UWB communication systems suitable for CMOS integration is proposed. The PN code representing the pulse position is converted into a corresponding analog voltage and compared with the outputs of two precision ramp generator circuits. The ramp generators employ a negative feedback principle making their output robust against environmental and process variations in order to reduce jitter. The circuit also features a time-interleaved architecture to ease constraints on devices such as the DAC and integrator circuits. The circuit has been designed and fabricated in AMI 0.5 mum CMOS technology.