The National Instruments PXI-6561 is a high-performance PXI Digital Waveform Instrument designed for versatile digital signal applications. This 16-channel device operates with a maximum sampling frequency of 100 MHz and interfaces with up to 20 low-voltage signaling digital pins. The PXI-6561 is available in several configurations, differentiated by onboard memory capacity: 2 Mb/channel (Part Number 778993-01), 16 Mb/channel (Part Number 778993-02), and 128 Mb/channel (Part Number 778993-03). The instrument is capable of advanced synchronization, allowing seamless integration into mixed-signal test systems, with its onboard clock supporting frequencies from 48 Hz to 100 MHz.

Equipped with Synchronization and Memory Core (SMC) technology, the PXI-6561 enables users to customize parameters such as the number of waveforms stored in memory, samples per waveform, and instruction sets. It supports two generation modes: single-waveform mode for producing a single output and scripted mode for executing complex sequences of waveforms. The device features five trigger types—Start, Pause, Script, Advance, and Reference—facilitating precise control over waveform generation and acquisition.

The PXI-6561 is compatible with NI-HSDIO driver software, which provides configuration and control capabilities through various development platforms, including LabVIEW and Microsoft Visual C/C++. Additional software tools such as the Digital Waveform Editor further enhance usability. With physical dimensions of 8.5 x 0.8 x 5.1 inches and a weight of 12 oz., the PXI-6561 is designed for efficient integration into automated systems. Although the PXI-6561 has been declared obsolete by National Instruments and is no longer manufactured, it remains available for purchase and repair services through Apex Waves.