PXI-VideoSPX-i (Digital Video deserializer input module) (LEGACY)
- Updated2023-08-17
- 5 minute(s) read
PXI-VideoSPX-i (Digital Video deserializer input module) (LEGACY)
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Note The NI PXIe-1491 has replaced the PXI-VideoSPX-i in NI VMS test systems. While NI VMS still supports the PXI-VideoSPX-i legacy hardware solution, NI does not recommend using the PXI-VideoSPX-i in new test systems. Refer to the NI Video Measurement Suite Readme for information about the latest recommended hardware solutions. |
The VideoSPX-i is designed for a NI VMS digital video solution in a stand-alone PXI chassis.
The PXI-VideoSPX-i input module allows the NI VMS test system to receive digital video signals and to perform analysis of digital video signals. The module is a PXI module intended for use in a PXI chassis. The input module serves as interface between a DVI source and a digital I/O module from National Instruments, such as the NI-6542/6545 100/200 MHz digital I/O. The input module features a DVI-compliant input on a 19-pin HDMI connector, a clock output available on an SMB connector, and a 68-pin digital interface connector.
The module accepts a DVI-compliant digital video signal on its Digital Video Analyser HDMI input, converts the signal to a parallel signal designed to be loaded into NI VMS through the NI-6542/6545 32 channel digital waveform acquisition board. The module is labeled "Digital Video Analyzer" to reflect its use, and is also known as a digital video de-serializer to reflect its function.
The table below summarizes the available interfaces of the VideoSPX-i:
| Input Channels | 1 x HDMI |
| Output Channels | 1 x 68 pin VHDCI |
| Clock output (3.3 V level) | 1 x SMB, series terminated |
Installation and cabling hints
The PXI-VideoSPX-i input module may be inserted into the following types of 3U slots in a PXI chassis:
- CompactPCI
- 3U PXI-1 Slot
- 3U PXI Express Hybrid Peripheral Slot
The figure below shows how the PXI-VideoSPX-i input module has been inserted in slot 7 in a NI PXIe-1062Q PXI chassis.
The figures above show a close-up of the PXI-VideoSPX-i.
The cables for interconnecting modules and to connect the NI VMS test system to your unit under test (UUT) include:
- HDMI cable from the UUT source to the PXI-VideoSPX-i input module. Use a DVI-HDMI adaptor, if necessary.
- VHDCI cable between the PXI-VideoSPX-i input module and a digital I/O module (NI PXI-6542)
- Clock cable with SMB connector in both ends, from the clock source (CLOCK) to the digital I/O module (CLK IN)
- Clock cable (if required) to the clock input on the output module. Refer to the manual for information about clock selection.
- Clock cable (if required) from the clock output on the input module
HDMI Input Connectors and Adapters
Three different types of connectors (A, B and C) are defined by the HDMI specification.
The PXI-VideoSPX-i input module uses a type A HDMI connector. The following table specifies which connector to use to connect the PXI-VideoSPX-i to different devices under test:
| device under test | Connector or adapter to use |
|---|---|
| devices using type-A HDMI connectors | type A cable |
| devices using type-B HDMI connectors | type A to type B cable adapter. Allows the PXI-VideoSPX-i input module to interface to the first of the two TMDS links of a HDMI type B connector. |
| devices using type-C HDMI connectors (cameras and similar devices) | type A to type C cable adapter |
| devices using DVI-D or DVI-I connectors | DVI to HDMI adapter or cable |
Clock Rates
The PXI-VideoSPX-i input module includes an SMB clock output to support applications that require this. The clock output is designed to drive a 50 W coaxial cable. The receiver should not terminate the clock. The clock driver runs on 3.3 V power, and your clock receiver must be compatible with this clock level. You may need to configure your clock receiver to accommodate the clock level.
The maximum resolution and the frame rate for NI VMS are limited by the maximum allowed clock rate through the digital I/O module . When using the NI PXI-6542 100 MHz digital I/O, the maximum allowed pixel clock rate is 100 MHz.
The lowest pixel clock rate guaranteed by the VideoSPX-i is 25 MHz. This clock rate determines the minimum resolution and frame rate supported by the input module. Legacy standard resolution ITU-R BT.601 video material, perhaps originating from PAL/NTSC, is encoded and distributed as interlaced video and has a pixel clock rate of 13.5 MHz which is too low for a DVI-compliant interface. Though not guaranteed, the VideoSPX-i may accept lower clock frequencies than 25 MHz, which may allow captures of e.g. digitized legacy video at the native 13.5 MHz clock rate. Also, your unit under test (UUT) may output low-rate material, such as legacy material, at multiple pixel rate for DVI compatibility. In that case, the VideoSPX-i will accept legacy material. Furthermore, if your UUT is a play-out device with de-interlacing and/or upscaling circuitry, you are likely able to output the legacy video material as progressive video with a sufficiently high pixel rate.DVI Video Acquisition
The DVI specification targets progressive RGB video formats. However, the VideoSPX-i input module support both progressive and interlaced formats, as well as RGB and YCbCr formats. The required color space conversion and the detection of interlace/progressive formats take place in the NI VMS software. The standards configuration file used by NI VMS to define the unique timing parameters of analog video signals is not required for the digital measurements. The VideoSPX-i input module acquire video material as 4:4:4 according to the DVI specification.For further information about the PXI-VideoSPX-i, you should consult the PXI-VideoSPX Input and Output Modules User Manual.