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Question about ADC sample bit width extension

ZHENGUO LU
Prodigy 50 points

If a signal S is divided into m intervals according to the amplitude, and then the corresponding amplitude interval is sampled by m n-bit wide ADCs, then whether this can be equivalent to an ADC with a bit width of n+log(2, m) sampling?

  • 0
    TI__Guru* 92655 points

    Zhenguo,



    Theoretically that is true. For example if you have a 12-bit ADC sampling a space of 0 to 0.5V, and then you had four ADCs sampling from ranges of -1.0V to -0.5V, -0.5V to 0V, 0V to 0.5V, and 0.5V to 1.0V, that would be equivalent to a 14-bit ADC sampling converter from ±1.0V.

    However, this implementation could be rather difficult. Is this in relation to one of our data converters? If so, which data converter are you asking about?



    Joseph Wu

  • 0 in reply to Joseph Wu
    Prodigy 50 points

    In fact, this is just a proposal for our current task. No ADC device is specified.

    The purpose of the task is to increase the sample bit width n.

    As you said, this solution is difficult to implement, such as ADC input protection, complex signal processing, and so on.

    for the issue of ADC selection, the following conditions must be met: the input range of the ADC is small, with input protection, and the bit width is large.

    Do you have  data converters that can be recommended?

  • 0 in reply to ZHENGUO LU
    TI__Guru* 92655 points

    Zhenguo,


    We have plenty of data converters to recommend. However, this depends on what you need for your system. How fast of a data rate do you need? What noise performance are you expecting? What is the input voltage range that is required? What is your system measuring? Before I recommend a data converter, I need to know what it is you need the system to measure.

    If you need a large bit width, I don't think it would be possible to construct a high bit ADC from multiple ADCs. Instead of doing that, it would be easier to use an ADC that had some programmable gain amplifier on the front end. Several of our devices have this type of amplifier integrated into the ADC. Some have limited range depending on the gain and common-mode range. Again, it's important to review what it is you are trying to measure.


    Joseph Wu