Using LoadCOFsf to set arbitrary sampling rates yields erroneous results

Tech Note: TN0278
Product: ActiveX
Version: All
Date Added: 2008-02-27

Issue

The ActiveX method LoadCOFsf is used to load a Control Object File (*.rco or *.rcx) and set the sampling frequency of a device. LoadCOFsf also allows arbitrary sampling rates to be set for rates of 50 and above, however not all devices support arbitrary rates. Setting unsupported arbitrary rates for the device yields erroneous results. Specifically, the RX6 and RX8 devices equipped with sigma-delta A/D or D/A converters do not support arbitrary sampling rates, so care should be taken to specify only realizable rates.

The RV8 and RX8 devices equipped with PCM A/D or D/A converters support arbitrary sampling rates.

Workaround

When using the RX6 or RX8 devices equipped with sigma-delta A/D or D/A converters refer to the RX6 realizable rates table on the RX6 Fast Facts on the TDT website.