When using the frequency display function of this scope, I am not getting a stable reading even though the source is accurate and constant. At 100Hz input, the display will fluctuate from 99.200 to 100.200 to 101.200. The same thing happens at 1000Hz or 100kHz. Is this normal for this scope? If not, it must mean I don't know what I am doing, or it is defective. This is a recent purchase that was physically damaged in shipping, other than the frequency issue it appears operationally fine. Does anyone know of a manual available for this scope other than the programing manual that is still available from HP?