TTY information lines in Pr

An example of the TTY information lines:

Zoom:x1, Navg:4, Start:0.00 usec (0.00 km), Span:5 usec 
Total:-63.3 dBm, Filtered:-77.6 dBm, MidSamp:-77.4 dBm 

Pr TTY information lines

Information line	Description
Zoom	The magnification (in amplitude) of the plotted samples. A zoom level of "x1" means that a full scale A/D waveform exactly fills the vertical height of the plot. Generally, the IF signal strength is not be quite this high. Use larger zoom levels to see the weaker samples more clearly. You may zoom in powers of two up to x128.
Navg	The number of spectra and/or LOG powers that are averaged together prior to plotting. Larger amounts of averaging increase the ability to observe subtleties of the signals, but the display updates more slowly.
Start	The starting time of the IF sample window relative to range zero. The time is shown both in microseconds and in kilometers.
Span	Time span of the IF sample window in microseconds.
IF	The IF-Input sources (SMA edge connectors) that provide the data being plotted.
Total	The total RMS power that is being detected by the IF-Input A/D converters. This total is computed using all of the raw IF samples in the chosen interval, and is the sum of power at all frequencies other than 0 Hz (and its aliases).
Filtered	The RMS power that falls only within the passband of the FIR filter for the current pulse width. This is computed using all of the raw IF samples in the chosen interval.
MidSamp	The RMS power within the passband of the FIR filter using only the raw IF samples in the center of the chosen interval.

The computation of Total Power is performed using the same subset of central IF samples that are used to compute Filtered Power. This smaller subset of IF samples comes about because filtering the data requires a convolution with the current FIR filter, and this computation does not produce results all the way to the edges of the input data. This is the same reason that the LOG plots do not extend across the full screen.

Because of this definition, it is valid to intercompare the Total Power and Filtered Power. The two numbers match exactly as long as all of the incoming power falls within the passband of the FIR filter. The difference between the two powers can be used as a measure of the filter loss for a given pulse shape, that is, the portion of signal that is lost outside of the filter's passband.