Spectrum Analyzerfor Anritsu RF and Microwave Handheld Instruments : Spectrum Analyzer : Limit Menu : Edit Menu (Limit)
  
Edit Menu (Limit)
Key Sequence: Shift > Limit (6) key > Limit Edit
SPA Limit Edit Menu (1 of 2)
Frequency
Press this submenu key to set the frequency of a limit line inflection point. The frequency of each inflection point in a limit line can be individually set. When a new point is added, it takes on a value halfway between two existing points, or it takes on the stop frequency of the current sweep if no point is higher in frequency than the one being added. See the Add Point submenu key description for more details. Use the keypad, the left or right arrow keys, or the rotary knob to change the frequency of an inflection point. The left or right arrows move the inflection point by 5% of the span.
Amplitude
Press this submenu key to set the amplitude of a limit line inflection point. The amplitude of each inflection point can also be individually set. By default, when a new point is added, it takes on the amplitude that is on the limit line at the frequency where the point was added. Use the keypad (using the ± key to set a negative value), the up or down arrow keys, or the rotary knob to move the point to the desired value. The unit of the amplitude limit is the same as the current vertical amplitude unit. See the Add Point submenu key description for details. The up or down arrows move the amplitude by 5% of the screen height.
Add Point
Press this submenu key to add a limit line inflection point. The precise behavior of this submenu key depends upon which inflection point is active at the time that the key is pressed. If the active limit point is somewhere in the middle of a multi‑segment limit line, then a new limit point is added that is halfway between the currently active point and the point immediately to its right. The amplitude of the inflection point will be such that it falls on the limit line. For example, if a limit point exists at 2.0 GHz with an amplitude of –30 dBm, and if the next point is 3.0 GHz with an amplitude of –50 dBm, then the added point will be at 2.5 GHz with an amplitude of –40 dBm. The frequency and amplitude values of the new point can be adjusted as needed with the Frequency and Amplitude submenu keys.
If the last limit point is active (assuming it is not at the right edge of the display), then the new limit point will be placed at the right edge of the display at the same amplitude as the point immediately to its left. Points may not be added beyond the current sweep limits of the instrument.
Edit Menu (Continued)
SPA Limit Edit Menu (2 of 2)
Add Vertical
In many measurement masks, step changes occur in the value of the limit line. Press this submenu key to add two inflection points. The two inflection points share the same frequency and are centered midpoint between adjacent measured points. The magnitudes of the points are set by using a visually intuitive algorithm that is based upon the adjacent inflection points.
You can adjust the magnitudes independently, but the frequencies of the two points remain linked and are adjusted as a vertical pair. Setting a discrete frequency, a limit inflection point will keep that exact frequency and place the limit point appropriately regardless of the frequency span. This is especially useful for emission mask verification.
Delete Point
Press this submenu key to delete the currently active point. The active point becomes the point that is immediately to the left of the point that was deleted.
Next Point Left
Press this submenu key to select the inflection point that is immediately to the left of the active point, making this newly selected point active for editing or deletion. With each key press, the active point becomes that point to the left of the previously active point, until the newly selected active point becomes the left‑most point on the screen.
Next Point Right
Press this submenu key to select the limit point immediately to the right of the active point, making this newly selected point active for editing or deletion. With each key press, the active point becomes that point to the right of the previously active point, until the newly selected active point becomes the right‑most point on the screen.
Back
Press this submenu key to return to the Limit Menu.