The SCALE menu for Smith Charts contain two unique buttons to control the display scale (Scale Selection) and control of the phase wrapping (Wrap Setup). Both are described in the sections below.
SCALE Smith Chart Impedance Menu
Menu Identification
• The appearance and button availability of the SCALE menu depends on the settings on the DISPLAY menu. Consult Scale Menus Appearance, Common Buttons, and Units for SCALE menu identification and prerequisites.
Prerequisites
• The TRACE FORMAT is set to Smith (R+jX Impedance).
This menu is available when TRACE FORMAT is set to:
• Smith (R+jX Impedance) and either
• Linear/Phase, Log/Phase, Real/Imaginary, Impedance, or L/C is selected.
Center Re(Z)
This sets the Real(ReZ) part for the center of the Smith Chart display. The field changes depending on the state of the Smith chart readout (log mag/phase, lin/phase, impedance, L/C).
Center Im(Z)
This sets the Imaginary (ImZ) part for the center of the Smith Chart display. The field changes depending on the state of the Smith chart readout (log mag/phase, lin/phase, impedance, L/C).
Scale Selection
The button displays the Smith Chart scale in dB. Select displays the SMITH SCALING menu.
Select displays the WRAP SETUP menu which allows the user to define if wrapping of on or off, and if on, the wrap offset in degrees.Additional Common Buttons
The SMITH SCALING Impedance and SMITH SCALING Admittance menus provide discrete Smith Chart scaling options from the default 0 dB display. Both the impedance and admittance menus provide the same functions. The user can zoom to areas of interest by expanding or compressing the display at the display at selectable levels as shown in Figure: SCALE Smith Impedance Menu
Prerequisites
• The TRACE FORMAT is set to Smith (R+jX Impedance).
• MAIN | Scale | SCALE Smith Impedance | SCALE SMITH IMPED. | SMITH SCALING IMPEDANCE
Button Selection Group
• The five buttons of the SMITH SCALING IMPEDANCE menu form a button selection group where the selection of any one button de-selects the other four buttons.
SCALE Smith Impedance Menu
0 dB (Refl 1.0) – The default Smith Chart Impedance scale is 0 dB with a reflection coefficient of 1.0.
–10 dB (Refl 0.3162278) – Expands the Smith Chart Impedance trace display and sets the scale to –10 dB with a reflection coefficient of 0.3162278.
–20 dB (Refl 0.10) – Expands the Smith Chart Impedance trace display and sets the scale to –20 dB with a reflection coefficient of 0.10.
–30 dB (Refl 0.0316228) – Expands the Smith Chart Impedance trace display and sets the scale to –30 dB with a reflection coefficient of 0.03162278.
+3 dB (Refl 1.4125375) – Compresses the Smith Chart Impedance trace display and sets the scale to +3 dB with a reflection coefficient of 1.4125375.
+10 dB (Refl 3.1622776) – Compresses the Smith Chart Impedance trace display and sets the scale to +10 dB with a reflection coefficient of 3.1622776.
+20 dB (Refl 10) – Compresses the Smith Chart Impedance trace display and sets the scale to +20 dB with a reflection coefficient of 10.
+30 dB (Refl 31.6227766) – Compresses the Smith Chart Impedance trace display and sets the scale to +30 dB with a reflection coefficient of 31.6227766.
Smith Chart Scaling Operations
A typical Smith Chart display is shown below at the default 0 dB setting.
Smith Chart Impedance Display – Typical Results at 0 dB
Expanded Smith Chart Displays
The user can zoom the display in by expanding the Smith Chart as shown in the figures below:
• The appearance and button availability of the SCALE menu depends on the settings on the DISPLAY menu. Consult Scale Menus Appearance, Common Buttons, and Units for SCALE menu identification and prerequisites.
Prerequisites
• The TRACE FORMAT is set to Smith (G+jB Impedance).
This menu is available when TRACE FORMAT is set to Smith (G+jB Admittance) and either Linear/Phase, Log/Phase, Real/Imaginary, Impedance, or L/C is selected. Button units are set to:
• Button Units: º (Degrees)
Center Re(Y)
This sets the Real(ReY) part for the center of the Smith Chart display. The field changes depending on the state of the Smith chart readout (log mag/phase, lin/phase, impedance, L/C).
This sets the Imaginary (ImY) part for the center of the Smith Chart display. The field changes depending on the state of the Smith chart readout (log mag/phase, lin/phase, impedance, L/C).
Scale Selection
The button displays the Smith Chart scale in dB. Select displays the SMITH SCALING menu.
Select displays the WRAP SETUP menu which allows the user to define if wrapping of on or off, and if on, the wrap offset in degrees.Additional Common Buttons
