====== "at" measure ======

===== Purpose =====

Measure a signal at a time or frequency.

===== Syntax =====

  at(probe="p(d)"  at=time  derivative)
===== Parameters =====

|probe       |The name of a probe to measure.  |
|at\\ x      |Measure the value here.  |
|derivative  |Flag: measure the derivative instead of the value.  |

===== Diagnostics =====

If you specify x to be out of range, it returns the value at the end, with a derivative of zero.

If you didn't store the waveform (see store command), it throws a "no match" exception, which prints "no match".

===== Examples =====

  measure sample = at(probe="v(out)", at=4u)
Measure the value of "v(out)" at 4 microseconds.
  measure sample = at(probe="v(out)", at=4u, derivative)
Measure the derivative of "v(out)" at 4 microseconds.