Cambridge Consultants are working radio transmitter with only digital parts, code-named Pizzicato 

No analogue filters and mixers - just good old regular digital logic. This is a big deal, and no one has done it before.

Despite the buzz around an increasingly digital world, so called ‘Software Defined Radios‘ today have one foot firmly in the analogue past. Mobile phones, Wi-Fi access points, police radios and Bluetooth headsets all use analogue circuitry to handle radio frequencies.

Using new mathematical tricks mean the group can compute multi-Gigabit/second, digital waveforms in real time without a supercomputer. Software can shape and control this waveform, making almost any signal imaginable at any frequency.

More information - http://blog.cambridgeconsultants.com/wireless-product-development/a-radio-with-no-analogue-parts/