IviDownconverterFrequencyStep Behavior Model

The following state diagram shows the behavior of the IviDownconverterFrequencyStep extension group:

Setting the IVIDOWNCONVERTER_ATTR_FREQUENCY_SWEEP_TRIGGER_SOURCE attribute to IVIDOWNCONVERTER_VAL_TRIGGER_SOURCE_IMMEDIATE continuously generates frequency steps from start to stop with fixed increments, or steps. The duration of one step is defined with the IviDownconverter_ConfigureFrequencyStepDwell function. Setting the IVIDOWNCONVERTER_ATTR_FREQUENCY_SWEEP_TRIGGER_SOURCE attribute to IVIDOWNCONVERTER_VAL_TRIGGER_SOURCE_EXTERNAL or IVIDOWNCONVERTER_VAL_TRIGGER_SOURCE_SOFTWARE delays the start of the next step until the specified trigger event occurs. This behavior is shown in the following figure:

In addition, the following rules apply:

• When you call IviDownconverter_ConfigureRFInputFrequency of the base capability group, the IVIDOWNCONVERTER_ATTR_FREQUENCY_SWEEP_MODE attribute is set to None, stopping any sweeps that may be in progress.
• When you set the IVIDOWNCONVERTER_ATTR_FREQUENCY_SWEEP_MODE attribute is set to Frequency Step, setting the IVIDOWNCONVERTER_ATTR_RF_INPUT_FREQUENCY attribute of the base capability group sets the IVIDOWNCONVERTER_ATTR_FREQUENCY_SWEEP_MODE attribute to None.
• When you change the IVIDOWNCONVERTER_ATTR_FREQUENCY_SWEEP_MODE attribute from any sweep mode to None, the downconverter uses the previously set value of the IVIDOWNCONVERTER_ATTR_RF_INPUT_FREQUENCY attribute of the base capability group.