National Instruments PXI-5621 Digitizer

The National Instruments PXI-5621 (Part Number: 189182A-02) is a 14-bit, 64 MS/s, high-speed, DC-coupled Digitizer. This model supports DC coupling, which is the only difference between the PXI-5620 and PXI-5621. This model comes with one channel and a sample rate range from 1 kS/s to 64 MS/s. The PXI-5621 operates with 50 Ω nominal input impedance and is designed to handle +8 dBm (±0.794 Vp) input signal level with dither enables. As far as its triggering capability is concerned, this model supports software, digital, and immediate triggering modes. The NI PXI-5621 requires one PXI Slot for operation and has dimensions of 3.9 x 6.3 x 0.8 in.

This Digitizer comes equipped with an external frequency reference input (SMA female connector) and one External Trigger (PFI 1 - SMB male). Since this model is a DC-coupled Digitizer, the NI PXI 5621 offers a wider passband and can acquire DC signals as well. With this model, the input impedance of the source and the input impedance of the Digitizer form a voltage divider to attenuate the input signal.

To lower the amount of distortion because of differential nonlinearity in the Analog-Digital-Converter, the National Instruments PXI-5621 adds Dither to the input signal between 150 Hz and 4 MH. The Dither can be enabled or disabled through software by the user. It is to be noted that the dither operation is not recommended during the sampling of time-domain data. The NI PXI-5621 has 64 MB memory buffer and supports multi-record capturing mode as well.

PXI-5621 Obsolete Status has been announced by National Instruments, but the Digitizer will still be available for purchase and repairs by Apex Waves.