It is available either as a standalone application or as VSTi for using in a host application such as Sonar, Cubase, Ambleton etc.
There are two oscillators to create the carrier waves which can both be phase modulated by a sine wave. You can choose the carrier waveform and apply an attack, decay, sustain and release envelope whose amount can be adjusted. The Freq PM knobs control the phase modulation frequency, 0 is no modulation 1 is full modulation at half sampling rate. Oscillator 2 can be detuned. The output can be fed through two filter banks with cutoff, resonance and track as well as ADSRs’ affecting the filters. Programs can be saved. There are 10 factory sounds preloaded in the synth courtesy of Yoa out of the 20 available program slots in each program bank.
More info: Blue Synth PM