Open-loop wide-bandwidth phase modulation techniques

The ever-increasing growth in the bandwidth of wireless communication channels requires the transmitter to be wide-bandwidth and power-efficient. polar and outphasing transmitter topologies are two promising candidates for such applications,in future. both these architectures require a wide-bandwidth phase modulator. open-loop phase modulation presents a viable solution for achieving wide-bandwidth operation. an overview of prior art and recent approaches for phase modulation is presented in this paper. phase quantization noise cancellation was recently introduced to lower the out-of-band noise in a digital phase modulator. a detailed analysis on the impact of timing and quantization of the cancellation signal is presented. noise generated by the transmitter in the receive band frequency poses another challenge for wide-bandwidth transmitter design. addition of a noise transfer function notch,in a digital phase modulator,to reduce the noise in the receive band during phase modulation is described in this paper. © 2011 nitin nidhi et al.