## Switching Modes

In the NCS we distinguish the following 4 “Switching Modes”:

TOTAL POWER

BEAM SWITCHING

WOBBLER SWITCHING

FREQUENCY SWITCHING (only with heterodyne receivers)

The corresponding commands are:

    SWTOTAL
    SWBEAM
    SWWOBBLER
    SWFREQUENCY

BEAM SWITCHING, WOBBLER SWITCHING, and FREQUENCY SWITCHING are realized by a system with hardware synchronization signals that allow a precise and fast switching within subscans.

TOTAL POWER simply means that none of the other 3 switching modes is active.

The system switches through a regular cycle with several (1, 2, or 4) switching phases.

The 4 switching modes are mutually exclusive, i.e., at any time the system uses only one of them.

During the transitions between phases, e.g., while the Wobbler is moving between its positions, no data are taken during the short “blanking” time.

The switching mode and its parameters should normally be set before choosing an observing mode, because for some observing modes details of the setup depend on the switching mode.