This paper proposes a configurable, spectrally efficient 7-tap FIR pulse based UWB transmitter with the maximum pulse rate of 1.6Gpulses/s. By utilizing a PLL and a DAC embedded FIR pulse generator, digitally configurable pulse generation is done with high spectral efficiency. For low power 7-tap FIR pulse generation, a 1/8-rate, 16-phase injection-locked oscillator (ILO) is designed instead of the full-rate 15GHz PLL. A prototype 50pJ/pulse UWB transmitter is implemented in 90nm CMOS, consuming 80mW power from a 1.2V supply voltage.