Askey Automates Testing of Set-Top-Box with NI Modular Instrumentation

Author(s):
Steve Chen - Askey Computer Corporation

Industry:
Electronics

Products:
LabVIEW, Digitizers/Oscilloscopes, TestStand,

The Challenge:
Creating an automated, low-cost, and scalable full-functional test system for Askey Set-Top-Box.

The Solution:
Using National Instruments LabVIEW 7 Express with the NI PCI-5911 100 MHz flexible resolution digitizer for audio and video parametric testing of a cable set-top-box and for integrating the test code into NI TestStand for complete automated and modular production testing with database and statistical process control analysis capabilities.

Audio and Video Test Needs
Askey Computer Corporation is a market leader in the design, marketing, manufacturing, and distribution of broadband and wireless products for ODM/OEM customers worldwide. With continuous progress in new product development, we have become the world leader in manufacturing of cable modems, ADSL modems, wireless LAN products, and analog modems. With increased demand for digital data in homes, we have seen a tremendous increase in demand for our set-top-box products. Therefore, we wanted to build an automated test system to increase test throughput and production yield while lowering the total cost of testing.

Cable set-top-box testing typically includes video, audio, modem, network, and various I/O. Testing for standard analog video, such as NTSC and PAL, is required on all models. Some higher-end models may need testing of S-video, component video, HDTV, and digital video interface. Most models also require analog audio testing and some may require testing of digital audio such as SPDIF. For all these products, we have very high standards for video and audio quality test. We will perform up to 10 nonlinear video measurements and five audio measurements to ensure each product meets our high manufacturing quality requirements. Typical video tests include sync and burst amplitude, chroma/luma gain, differential gain, and differential phase. And typical audio tests include gain, noise level, signal-to-noise ration, and total harmonic distortion.

Fast, Low-Cost Audio Video Test Solution
We knew our test throughput needs could not be met by test systems based on traditional instrumentation. Instead, we needed a PC-based test solution to lower test costs and meet throughput requirements. We chose the PCI-5911 100 MHz high-speed digitizer with flexible resolution because it met the high-bandwidth requirement of video testing and high-resolution requirement of audio testing. The resolution of PCI-5911 ranges from eight bits at 100 MS/s to more than 21 bits at 10 kS/s. The PCI-5911 is synchronized via the real-time system integration (RTSI) bus with the NI PCI-1411 video acquisition card to offer real-time video trigger and capture. The PCI-1411 is not only used to trigger on each video line, but it also displays live video feed for operators to perform quick visual checks. The PC-based architecture uses the fastest CPU to deliver quick and accurate video analysis capabilities. We use an NI LabVIEW-based video and audio analysis library developed by Karma Technology to perform the required tests. Because functionality on set-top-boxes changes rapidly and there is strong time-to-market pressures in the consumer electronics industry, we needed a test solution that was flexible and modular. We developed test code based on LabVIEW 7 Express that could be reused. We then built test sequences using NI TestStand that we could easily tailor based on the test requirements of each model.

NI TestStand provided a common framework for test sequencing and built-in database capabilities. Its flexible and open source code operator interface also gave us full control over the operator interface look and feel. By using LabVIEW 7 Express and NI TestStand for test development, we significantly reduced software development costs.

Meeting Future Test Needs
As accuracy requirements increase, we plan to upgrade our existing test system to a higher-end test system based on the new NI PCI-5122 14-bit 100 MHz digitizer with built-in video triggering. The PCI-5122 will be able to deliver 14 bits of accuracy and more than 75 dB spurious-free dynamic range for video testing, which will outperform most standard video analyzers today.

Using NI PC-based modular instrumentation and LabVIEW 7 Express, we were able to develop a low-cost, automated audio video test system that met our requirements. At the same time, it is scalable to meet future testing needs. As a market leader in broadband and wireless products, we were able to maintain high test standards with lower test costs by using NI technology.

For more information, contact:
Steve Chen
Director of Product Engineering
Askey Computer Corporation
www.askey.com

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