The target output voltage of a correlator total-power detector.

Input Format:

A floating point number of volts between 0 and 10.

Operators:

-a

The unary minus operator changes the sign of its operand.

Use with do-loops:

When a TotalPower variable is used as the dependent variable of a do-loop, the associated loop increment is specified as a Double constant.

Examples:

The following example tells the channelizer to insert enough attenuation into the signal path of each channel to result in approximately 5.3V volts being measured by the total power detectors of all correlator inputs.

  tp all, all, 5.3

Context:

The total power detectors in the CBI correlators are sampled by A/D converters that produce measurements of their input voltages. In order to set the total power inputs to the correlators one potentially has to insert different attenuations for each frequency band and each antenna. The amount of attenuation required depends upon the brightness of the input source, so different attenuations will be needed when observing planets than when observing the CMB. The tp command initiates an iterative process to find the attenuations that produce total powers as close as possible to the specified total power. The target total power is specified as a A/D output voltage. This is compared against the measured total powers at the end of each integration, after removing previously measured zero-offsets.