What can I use the PXIe-6544/45 (Digital Waveform Generators/Analyzers) for?

Publish Date: Jun 22, 2009 | 4 Ratings | 4.50 out of 5 |  PDF

Overview

Mobile phones, high-definition televisions, computers, GPS units, and even simple semiconductor devices all require faster and larger amounts of digital data. To address these applications, National Instruments recently released the NI PXIe-6544/45 100/200 MHz high-speed digital input/output devices, which are ideal for faster clock and data-streaming rates. In the following paragraphs, explore some of the applications that are possible with the NI PXIe-6544/45. The two main applications discussed are chip testing and multimedia testing and communication.

Table of Contents

  1. ATE, Communication, and Digital Interfacing
  2. Chip Testing
  3. High-Data Bandwidth Testing
  4. Conclusion
  5. Related Links

1. ATE, Communication, and Digital Interfacing

The enhanced features of the NI PXIe-6544/45 devices make them ideal for multiple applications. They give you the power to synchronize multiple digital or analog instruments to create a tightly synchronized multichannel system.

The devices are ideal for applications requiring fast rates and fast data transfers such as memory testing. Use them to communicate with or emulate memory. Programming environments such as NI LabVIEW, LabVIEW SignalExpress, and the Digital Waveform Editor make it easy to reprogram the NI PXIe-6544/45 to communicate with different memory formats. Furthermore, you can test and emulate buses such as ISA or the PCI bus.

The voltage levels and rates of the NI PXIe-6544/45 devices also make them optimal for protocol communication. Program the devices to act as a master or slave for multiple protocols such as Serial Peripheral Interface (SPI) or Inter-Integrated Circuit (I2C). Also perform comparisons of data acquired in software. In addition, use the NI PXIe-6544/45 in conjunction with other PXI/PXI Express-based instruments to create a complete automated test system.

≫ Compare high-speed digital products.

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2. Chip Testing

The NI PXIe-6544/45 devices feature faster rates at up to 200 MHz per channel. These speeds expand chip testing capabilities to include chips that are faster and could not be tested before.

For example, with a 16-bit, parallel interface, 200 MS/s dual-channel digital-to-analog converter (DAC), you can use the NI PXIe-6545 to generate data on 16 lines (continuously or in bursts) to test the DAC at its maximum clock rate. You can also pair this device with other NI modular instruments such as digitizers or source measure units (SMUs) to characterize the DAC for various tests including spurious free dynamic range (SFDR), signal-to-noise ratio (SNR), intermodulation distortion (IMD), integral nonlinearity (INL), and differential nonlinearity (DNL) tests at higher rates.

Figure 1 – The PXIe-6545 can be used to test a 200MSPS digital to analog convertor (DAC)

You can even use the NI PXIe-6545 to test two 16-channel DACs in parallel. The digitizer can be used to acquire and analyze the data for linearity or dynamic characteristics.

Also use the same digital board to test analog-to-digital convertors (ADCs). Instead of a digitizer, an arbitrary waveform generator can generate data to an ADC. NI PXIe-6545 can then acquire the digital data from the ADC. Easily analyze this data for linearity and dynamic characteristics.

Figure 2 – The PXIe-6545 can also be used to test the digital components of an analog to digital convertor (ADC)

These are only two scenarios of chip testing. You can test various chips for various types of testing using NI high-speed digital and analog devices.

The NI-HSDIO API can be used with a graphical programming language such as LabVIEW or a text-based language such as NI LabWindows™/CVI or C for generation and acquisition of digital signals. Each channel on the NI PXIe-6544/45 devices can be programmed for input or output. You can have parallel generation and acquisition sessions on a different number of channels each. You can also program the digitizer or ARB in LabVIEW and run all instruments in a single intuitive environment.

Once the data is acquired, tools in LabVIEW such as the Sound and Vibration Toolkit can be used to calculate SNR, SINAD, total harmonic distortion (THD), and so on.

Figure 3 – Express VIs in LabVIEW can be used to calculate dynamic characteristics

Figure 4 shows dynamic characterization of a digital to analog converter (DAC).  The applications is created using NI LabVIEW and the sound and vibration toolkit.

 

With the onboard direct digital synthesis (DDS) clock, you can clock your data at highly precise frequencies. You can programmatically select frequencies from DC to 200 MHz with sub-Hz resolution. If you have a DAC that can be programmed for multiple frequencies (for example, 125 MSPS or 200 MSPS), you can use the onboard clock to test this DAC at both frequencies, without having to use an external clock. With the selectable voltages of 1.2, 1.5, 1.8, 2.5, and 3.3 V, you can also test your unit under test (UUT) for multiple voltage levels

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3. High-Data Bandwidth Testing

The streaming capabilities on the NI PXIe-6545 open up a whole range of tests that can now be conducted. The PXI Express architecture allows for up to 660 MB/s to PC memory and 400 MB/s from PC memory on the NI PXIe-6544/45 devices. These devices have an x4 PXI Express link, which has a theoretical maximum of 1 GB/s. The rates mentioned above are achieved using a RAID array.

Figure 5 – Multiple PXI Express based digital instruments can be used to create a high bandwidth system.

 

Multimedia tests requiring high bandwidths such as HDMI and HD audio tests can be achieved with the streaming capabilities of the NI PXIe-6544/45 devices. The image below shows how you can stream data from disk to the digital instrument over PXI Express.

Figure 6 – This image shows the process of data flow in a high data bandwidth system.

 

The diagram above applies to streaming digital data from a RAID array to the NI PXIe-6544/45 devices. The data stored on the RAID array could be video data for HDMI or DVI testing. It could be audio data for HD audio testing or even GPS data for GPS streaming applications.

The following four steps show how you can stream data to an NI PXIe-6545:

a.        The entire data file is stored on the RAID array. This could be any kind of file.

b.       The data file is transferred from the RAID array to the PXI Express chassis through the NI 8262. This data is then transferred to the host computer or controller.

c.        Once the data is in the PC memory, it can be fragmented into smaller chunks. These chunks can then be sent over the PXI Express link back to the digital instrument.

d.       The chunk is transferred to the onboard memory of the NI PXIe-6545, from where it is generated on the pins of the device. The clock rate, number of pins, and so on can be set using the NI-HSDIO driver on the host PC.

≫ See more information on video and audio testing.

 

You can use the PXI platform to lower the cost of video test. With the modular architecture of PXI, you can test not only analog and digital video, but audio as well in the same platform. You can even add video pattern generation to a test system.

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4. Conclusion

With the features of the NI PXIe-6544/45, you can test devices and communicate with components not possible before. The higher data and streaming rates coupled with the synchronization and timing capabilities of the SMC architecture make the NI PXIe-6544/45 ideal digital instruments for a wide variety of digital tests and communication.

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5. Related Links

View Specifications for NI PXIe-6544/45
Advanced Features of High-Speed Digital Instruments
Webcast on Benchmarks of the NI PXIe-6544/45

The mark LabWindows is used under a license from Microsoft Corporation. Windows is a registered trademark of Microsoft Corporation in the United States and other countries.

 

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