The reference level is the top grid 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.

The 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.

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.

Press this submenu key and use the keypad, the rotary knob or the arrow keys to change the attenuation value.

RL Offset compensates for the presence of external input attenuation or gain. Enter a positive value to compensate for gain or loss and then press the appropriate submenu key (dB External Gain or dB External Loss). The new RL Offset value will be displayed on the button.

Select the display units from this submenu key, for example:

This submenu key turns the low‑noise front‑end preamplifier on or off. To assure accurate measurement results, the largest signal into the instrument input when the preamplifier is turned on should be less than –40 dBm.

Several detection methods tailor the performance of the instrument to meet specific measurement requirements. In general, there are more measurement points across the screen than display points. The various detection methods are different ways of dealing with how measurement point will be shown at each display point. Opens the Detection Menu.

 

This method causes the largest measurement point to be shown for each display point, assuring that a narrow peak is not missed.

In the Preset case, when the VBW/Average Type is set to Linear, this method detects the average power of sample points that go into the display point. In the case where VBW/Average Type is set to Log, the traditional average of log(power) is displayed for the detector, as well as for VBW and trace average.

This method causes the smallest measurement point to be shown for each display point. Typically this mode is used to help detect small discrete signals in the presence of nearly equal values of noise. The display points that contain only noise will tend to show lower amplitudes than those that contain discrete signals.

This is the fastest detection method because for each display point, only one frequency point is measured. Use this method when speed is of paramount importance and the possibility of missing a narrow peak is not important.

When this selection is made resolution bandwidths and video bandwidths of 200 Hz, 9 kHz and 120 kHz are available. This detection method is designed to meet CISPR requirements.

Returns to the Amplitude Menu.