Requirement:
500MHz or faster CPU. Sample rates higher than 48 kHz may require faster CPU
Editors Note
Mac the Scope, is one professional signal analyzer of its kind with some extra features. It has got a 1/3 Octave RTA which includes a spectogram/sonogram display. It also has an embedded precision waveform and a signal generator. The wavebox signal generation options can be easily customized according to your needs.