This paper describes an FM-UWB transceiver system which employs M-PSK modulated subcarriers for high throughput data transmission. Compared to conventional 2-FSK FM-UWB transceivers, the proposed M-PSK FM-UWB transceiver can increase data rate with minimal increment of RF front-end complexity. A regenerative FM demodulator followed by a low-frequency M-PSK demodulator enables low-power low-cost receiver design with enhanced energy efficiency. Simulation results show that the 8-PSK 3.5-4GHz FM-UWB transceiver system successfully modulates and demodulates 8-PSK data, achieving three time the energy efficiency of the conventional FM-UWB system.