Auto versus Coupled

During emission measurements most of the Spectrum Analyzer settings have an 'Auto' and a 'Coupled' value.

• The 'auto' function is selecting the 'Auto' function inside the receiver itself
• The 'coupled' function is selecting the 'Auto' function inside the receiver itself

Yes indeed, these options are doing the same thing!

We finally plan to implement a difference between the 'Auto' and 'Coupled' functions, where 'Coupled' is the 'Auto' functionality of the receiver. The 'Auto' function would then be 'The best value determined by the RadiMation software'. However this 'Auto' functionality is not implemented yet.

Until the 'Auto' function is implemented, it is better to remove the 'Auto' function from the list of possibilities. We already created a wish for this in the past: '#1316: Emission measurements: Auto => coupled'.

Until the 'Auto' function is removed from the list of options, it doesn't matter which option is selected, because they both will select the 'Auto' function of the receiver.

Attenuator

The 'Auto (0 dB)' option for the attenuator is setting the Attenuation to 'auto' mode, allowing that 0 dB is a valid attenuation setting. The input attenuation protection of most receivers is then disabled. The 'Auto (10 dB)' option of the attenuator is setting the attenuation to 'auto' mode, but the 0 dB attenuation setting is then not allowed. The minimum attenuation in this situation is thus 10 dB.

Reference level

It is strongly advised to not set the 'Reference Level' to 'Auto' because this will very often result in a reference level of 0 dB, which results in a lot of other problems, like the measured value being clipped to 0 dBuV.

It is better to always set the reference level to a 'fixed' value of for example 70,80,90 or 100 dBuV.