1. A method for recording and outputting a waveform, the method comprising: receiving analog data; converting the analog data to digital data, the digital data representing variations in a signal voltage of the analog data over time; storing a sample of the digital data in a memory of a protocol analyzer; presenting the sample of the digital data as a waveform on a user interface of the protocol analyzer; collecting a trace of data that constitutes a user-specified event; analyzing the data in the trace; and presenting an analysis of the data on the user interface of the protocol analyzer, wherein presenting the sample of the digital data as a waveform comprises presenting as a waveform a portion of the digital data that constitutes the user-specified event in the trace of data.