Signal Types in LabVIEW SignalExpress

LabVIEW SignalExpress categorizes signals based on their type, such as time-domain signals, frequency-domain signals, scalar values, or Boolean values. Time-domain signals appear on a graph where a signal value (such as amplitude) corresponds to a time. Frequency-domain signals appear on a graph where the level of a signal corresponds to a frequency value. Scalar values appear in tables as single values or a collection of single values, such as the result of a DC measurement or a tone-frequency measurement. Boolean values appear as vertical or horizontal LEDs. LabVIEW SignalExpress can manage the different signal types in the following ways:

• You can process only signals that make sense for a specific step. For example, you only can perform a power spectrum operation on a time-domain signal.
• You cannot mix signal types that are incompatible. For example, you cannot add time-domain signal values to the resulting values of a power spectrum.
• You can add a phase signal represented in degrees to a phase signal represented in radians. LabVIEW SignalExpress converts the different signal types.
• You cannot display incompatible signals on the same graph. For example, you cannot display a time signal and the result of a power spectrum on the same graph.

Steps Can Process Different Signal Types

Some steps can process more than one signal type. For example, the Scaling and Conversion step can scale a time-domain signal (applying gain and offset values) or can scale a frequency-domain signal.

The available scaling operations depend on the type and unit of the signal. If the input signal is a frequency-domain magnitude signal, you can apply a gain to the magnitude signal. If the input signal is a frequency-domain phase signal, you can apply a delay correction value.