Recording analog characteristics of data from a data line in a protocol analyzer

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.

2. The method as recited in claim 1 , wherein storing the digital data in memory comprises storing the digital data consistent with a FIFO scheme.

3. The method as recited in claim 1 , wherein presenting the digital data as a waveform comprises presenting the digital data visually as a waveform.

4. A protocol analyzer that is configured to record and output a waveform, the protocol analyzer comprising:

an analyzer module comprising a trace buffer;

a waveform capture module comprising:

an analog-to-digital converter whose input comprises an analog data stream and whose output comprises a digital data stream that corresponds to the analog data stream, the digital data stream representing variations in a signal voltage of the analog data stream over time;

a filter whose input comprises the digital data stream output from the analog-to-digital converter and whose output comprises those portions of the digital data stream that correspond to a user-specified event; and

a memory whose input and output comprise the portions of the digital data stream output from the filter; and

a user interface whose input comprises the portions of the digital data stream output of the memory and whose output comprises the portions of the digital data stream output of the memory presented as a waveform.

5. The protocol analyzer as recited in claim 4 , wherein the user interface comprises a graphical user interface.

6. The protocol analyzer as recited in claim 4 , wherein the stored digital data is consistent with a FIFO scheme.

7. The protocol analyzer as recited in claim 4 , wherein the output of the user interface further comprises data stored in the trace.

8. The protocol analyzer as recited in claim 4 , wherein the data stored in the trace corresponds to the portions of the digital data stream output from the filter and stored in the memory.