The frequencies of the transmitted signals on channels one, two and three etc. are given by SFO1, SFO2 and SFO3, etc., respectively. However, these frequencies may not be set directly (you will notice that they cannot be highlighted using the mouse).

The transmitted frequencies are controlled by setting offsets to basic frequencies BF1, BF2 and BF3 etc.

For the observe channel:

Transmitted frequency is automatically set by the user.

Similarly, for the next two decoupling channels:

When a specific nucleus is selected, the appropriate basic frequency is automatically set. After reading a standard parameter set, the basic frequency will be set correctly and only the offset values need to be adjusted.

Remember that SFOX is the most relevant parameter in that it is the frequency that is actually transmitted to the sample. Note also that the offsets can be set to zero in which case SFOX = BFX. A more detailed description is given in the next section.