Time Align (Graph Settings)

Default: 0.05%

Range: 0% to 50%

Time Align sets the size of the search range when aligning the stimulus and response waveforms. The size is specified in percentage of the stimulus waveform's length. The search algorithm can be thought of shifting the stimulus waveform backwards or forwards by the Time Align value to find the best correlation between the two waveforms.

Even when you specify 0% for Time Align, a small number of points will be used for alignment.

If the stimulus and response signals are not aligning properly, you can increase the percentage of the stimulus waveform you want the VSA to use for alignment. Be aware that increasing the percentage will make measurements slower.

The time alignment process uses sub-sampling to get a better time alignment than shifting by an integer number of samples. This means the points in the Graph traces will not exactly correspond to the points in the original stimulus and response traces, even when Time Reference is set to Stimulus or Response.

The time lengths of the measured stimulus and response waveforms are typically chosen to be similar in length. When the waveforms vary in length, the VSA uses the shorter length of the two waveforms. The compensated (including time-alignment) stimulus and response waveforms are available in the Stimulus Time and Response Time traces, respectively.

For alignment to occur correctly, the stimulus and response waveforms must be sufficiently correlated over a 100 sample window starting at some offset within the alignment window.

When you are using bursted signals, use triggering to ensure that the power-off portion of the signal does not occur at the beginning of the time record.