Spectrum Analyzer Measurement Guide : Spectrum Analyzer : Frequency Menu (Freq 1/2) with Offset Function
 
Frequency Menu (Freq 1/2) with Offset Function
Key Sequence: Freq
The tuning frequency range can be entered in several different ways depending upon what makes the most sense for the user or for the application. The center frequency and span can be specified, the start and stop frequencies can be entered, or a signal standard and channel number can be selected from the built‑in list. A user‑defined frequency offset, either positive or negative, can be entered to adjust the frequency that is displayed on the instrument from the actual swept frequency. Refer to Offset Frequency. When enabled, Offset is displayed at the bottom of the screen (Figure: 200 MHz Frequency Offset Example) and the Center Freq, Start Freq, and Stop Freq submenu keys indicate that a frequency offset is turned on.
Set the Freq Offset to 0 Hz to remove the frequency offset.
Note 
The Freq Offset will affect the displayed values of Frequencies, Markers, and Limits. The current frequency offset value is displayed in the Freq 2/2 Menu.
SPA Freq 1/2 with Offset Function Menu
Offset Center Freq
Press the Freq main menu key followed by the Offset Center Freq submenu key and enter the desired frequency using the keypad, the arrow keys, or the rotary knob. If entering a frequency using the keypad, the submenu key labels change to GHz, MHz, kHz, and Hz. Press the appropriate units key. Pressing the Enter key has the same effect as the MHz submenu key. With zero offset, this key differs, refer to Figure: SPA Frequency Menu (2 of 2).
Offset Start Freq
Press the Freq main menu key followed by the Offset Start Freq submenu key and enter the desired frequency using the keypad, the arrow keys, or the rotary knob. If a start frequency higher than the current stop frequency is entered, the stop frequency will be changed to yield a 10 Hz span.
Offset Stop Freq
Press the Freq main menu key followed by the Offset Stop Freq submenu key and enter the desired frequency using the keypad, the arrow keys, or the rotary knob. If a stop frequency lower than the current start frequency is entered, the start frequency will be changed to yield a 10 Hz span.
Span
Press the Freq main menu key followed by the Span submenu key and enter the desired span. Refer to Span Menu.
Signal Standard
Use the up or down arrow keys or the rotary knob to highlight a signal standard and press Enter to select.
When a signal standard is selected, the center frequency and span for the first channel of the last segment of the particular standard is automatically tuned. Other settings, such as channel spacing and integration bandwidth, are also automatically entered.
Channel #
Use the up or down arrow keys, the keypad, or the rotary knob to select a channel number for the selected signal standard. The center of the channel is tuned to the center of the spectrum analyzer display. The frequency value is the amount by which the center frequency differs from the center of the channel.
Step Size & Offset
Opens the Freq 2/2 Menu.
Freq 2/2 Menu
Key Sequence: Freq > Step Size & Offset
SPA Freq 2/2 Menu Offset Function
Freq Step
Press the Freq main menu key followed by the Freq Step submenu key to enter the desired frequency step size. The frequency step specifies the amount by which a frequency will change when the up or down arrow keys are pressed. The center frequency, start frequency, and stop frequency values can be changed using Freq Step. The active parameter will be changed by the frequency step when the up or down arrow keys are pressed. The frequency step size can be any value from 1 Hz to upper limit of the instrument with a resolution of 1 Hz. The frequency step value can be used to change start frequency, stop frequency, center frequency, and the frequency step size.
Use the keypad or the rotary knob to change the Frequency Step size.
Channel Increment
Sets the increment value for the Channel # submenu key.
Freq Offset
Enter the desired offset (positive or negative) using the keypad, the arrow keys, or the rotary knob. If entering a frequency by using the keypad, then the submenu key labels change to GHz, MHz, kHz, and Hz. Press the appropriate units key. Pressing the Enter key has the same effect as the MHz submenu key.
Offset Step Size
Enter the desired frequency offset step size. The offset frequency step specifies the amount by which the offset frequency will change when the up or down arrow keys are pressed.
Use the keypad or the rotary knob to change the Offset Step Size.
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Offset Example
200 MHz Frequency Offset Example