 | Center Freq Press this 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 displays the title Center Freq. With an offset other than zero, this key displays the title Offset Center Freq, as shown below the full menu. Refer to Freq 1/2 (Frequency Menu with Offset Function). Span Lets you set the frequency span to be displayed on the instrument. This submenu key shows the current value for span in units of GHz, MHz, kHz, or Hz. When the Span button is pressed, span becomes the active parameter and may be changed. Use the keypad, the directional arrow keys, or the rotary knob to increase or decrease the span frequency. If the span is changed using the arrow keys, the span changes in a 1‑2‑5 sequence for each key press. Reference Level The reference level is the top graticule line on the display, and can be set from +30 dBm to – 150 dBm. A value may be entered from the keypad, use the ± key for a minus sign. After entering the value press the dBm submenu key or the Enter key. The up or down arrow keys change the reference level in 10 dB steps, and the left or right arrow keys change the value by 1 dB. The rotary knob changes the value by 0.1 dB per click. The reference level value may be modified by the reference level offset value to compensate for an external attenuator or amplifier. Scale The y‑axis scale can be set in 1 dB steps from 1 dB per division to 15 dB per division. The value can be changed using the keypad, the rotary knob or the arrow keys. Auto Atten Input attenuation can be either tied to the reference level (On) or manually selected (Off). When input attenuation is tied to the reference level, attenuation is increased as higher reference levels are selected to make sure the instrument input circuits are not saturated by large signals that are likely to be present when high reference levels are required. Atten Level Press this submenu key and use the keypad, the rotary knob or the arrow keys to change the attenuation value. Back Returns to the IQ Waveform Capture Menu (Option 24). |