ADA2200 Program filter setting and Output waveform calculation

Hi,

There are two questions about use ADA2200.

1. Regarding to the ADA2200 Program filter function, Could you please help to provide some reference data for the Program filter setting. The datasheet doesn't tell too much about it.

2. Regarding to the output waveform, the datasheet says -

In the default configuration, there are eight output sample periods during each RCLK cycle. There are four updated output samples while the RCLK signal is high. While RCLK is low, the fourth updated sample is held constant for four additional output sample periods.  (Page 13, Mixer section)

Does it means only half cycle waveform will be present (As below figure) ??  How to calculate the input waveform value?

Hear from you soon and thanks!

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  • Hi Brent,

    The value of interest is the average value of the waveform.  While the output samples from the ADA2200 will not closely resemble the instantaneous input waveform, this is does not impact the accuracy of the average value. The datasheet accuracy specs were determined using the 8 sample method I suggested.

    Using 8 samples per cycle versus 4 samples for cycle will lower the noise floor due to the higher number of samples. You could use 4 samples instead of 8 per cycle, but unless you are trying to reduce the computational load on your micro, I would use 8 samples.

    Brian

Reply
  • Hi Brent,

    The value of interest is the average value of the waveform.  While the output samples from the ADA2200 will not closely resemble the instantaneous input waveform, this is does not impact the accuracy of the average value. The datasheet accuracy specs were determined using the 8 sample method I suggested.

    Using 8 samples per cycle versus 4 samples for cycle will lower the noise floor due to the higher number of samples. You could use 4 samples instead of 8 per cycle, but unless you are trying to reduce the computational load on your micro, I would use 8 samples.

    Brian

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