Extending your HSDIO Maximum Clock Rate with SerDesHardware: Digital I/O (DIO)>>High-Speed
Problem: How can I read a serial bitstream that is faster than the HSDIO maximum clock rate? Likewise, can I generate a serial bitstream at a higher clock rates? How can this be implemented with serializers and deserializers (SerDes), and which products does National Instruments recommend? Deserializer Overview If you have a high frequency serial bitstream that you'd like to acquire that is out of the maximum clock rate of the NI 6542 (100 MHz) and NI 6552 (100 MHz), you can use a deserializer to accomplish this task. In principle, a deserializer takes a serial bitstream (single channel), and multiplexes it into multiple channels. For example, a 1:10 deserializer takes a 1 GHz bitstream and deserializes the data into 10 channels of 100 MHz data. The 10 channels of data are then acquired on the HSDIO board, and can later be reconstructed in software into its original bitstream pattern. The figure below illustrates this concept with a simple 1:3 deserializer.
Serializer Overview Conversely, chip packages also exist that serialize data, which are aptly called serializers. These devices take multiple channels of parallel data, and combines the data into one faster bitstream. For example, 8 channels of 1MHz input data will be serialized into one channel of 8MHz output data. Many of these chips also provide both serializing and deserializing functionalities, and are called SerDes (serializer / deserializer). Common SerDes Manufacturers' Product Pages
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Report Date: 03/22/2007 Last Updated: 04/20/2007 Document ID: 47LELHJQ |
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