Vertical:Advanced:Flex FIR Antialias Filter Type

Short Name: Flex FIR Antialias Filter Type

The NI 5922 flexible-resolution digitizer uses an onboard FIR lowpass antialias filter. Use this property to select from several types of filters to achieve desired filtering characteristics. For most applications, the default value of this property is recommended. The other available filters are useful for optimizing settling time measurements of step responses.

Default Value: 48 Tap Standard

Defined Values

Note  Settling time values refer to the FIR filter only and do not take into account settling time caused by the analog front end. Refer to the NI PXI-5922 Specifications for combined digital and analog settling times.

48 Tap Standard (0)	This filter is optimized for alias protection and frequency-domain flatness. Alias protection: ranges from 80 dB to 100 dB depending on sample rate Settling time: within 14 samples from a 50% vertical trigger point Cutoff frequency: 0.4 × sample rate Flatness: Ripple ranges from 0.005 dB to 0.120 dB depending on selected sample rate (refer to the NI PXI-5922 Specifications for more information) Rise time: Approximately 0.75/(sample rate)
48 Tap Hanning (1)	This filter is optimized for the lowest possible bandwidth for a 48 tap filter and maximizes the signal-to-noise ratio (SNR). Settling time: within 14 samples from a 50% vertical trigger point Cutoff frequency: 0.030 × sample rate Flatness: 0 to –3 dB within cutoff frequency Rise time: 11.6/(sample rate)
16 Tap Hanning (2)	This filter is optimized for the lowest possible bandwidth for a 16 tap filter and maximizes the SNR. Settling time: 6 samples from a 50% vertical trigger point Cutoff frequency: 0.08 × sample rate Flatness: 0 to –3 dB within cutoff frequency Rise time: 7.7/(sample rate)
8 Tap Hanning (3)	This filter is optimized for the lowest possible bandwidth for an 8 tap filter and maximizes the SNR. Settling time: 4 samples from a 50% vertical trigger point Cutoff frequency: 0.15 × sample rate Flatness: 0 to –3 dB within cutoff frequency Rise time: 3.9/(sample rate)

Remarks

The following table lists the characteristics of this property.

Data Type	ViInt32
Access	R/W
Channel Based	Yes