The R&S SMA can be configured to provide level settings without interruption. It is possible for instruments with or without step attenuator. The attenuator mode is set in the "Attenuator Settings" section of the "RF level / EMF" dialog.
Sets the attenuator mode at the RF output.
"Auto" | Standard mode. The entire level range is available. The level settings are made in the area of the electronically switching attenuator as well as in the area of the relay-switched high power bypass (longer switchover time, wear). |
"Normal" | The level settings are made only in the area of the electronically switching attenuator. The high level ranges are not available. This setting is wear-free, as the relays are not switched. |
"High Power" | The level settings are made only in the area of the high-power bypass. Only the high level range is available. The relays are not switched. |
"Fixed" | The level settings are made without switching the attenuator and the relays. When this operating mode is switched on, the attenuator and the relays are fixed in their current positions to provide level settings without interruption. The resulting variation range is defined and displayed under "Attenuator Fixed Range". Note: The function is effective when automatic level control is activated ("ALC State = On"). If the normal variation range is overranged or underranged, level errors increase considerably and the warning "Level under/overrange" appears in the info line. The spectral purity of the output signal decreases with high attenuation. |
Displays the level range in which the level is set without interruption for the "Attenuator Mode fixed" setting.
Remote command:Selects the attenuator mode, when the RF signal is switched off.
The setting of the RF OFF mode is not affected by an instrument preset (PRESET key), *RST and the "Save/Recall" function. This parameter is influenced only by the "Factory Preset".
"Unchanged" | Freezes the setting of the attenuator when RF is switched off. The attenuator is only activated when RF is switched on. This setting is recommended if a constant VSWR (Voltage Standing Wave Ratio) is required. Furthermore, it provides fast and wear-free operation of the relay-switched high power bypass. |
"Full Attenuation" | Sets attenuation to maximum when the RF signal is switched off. This setting is recommended for applications that require a high level of noise suppression. |
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