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What is a pseudobipolar signal? I read this word in the datasheet below:

http://www.analog.com/media/en/technical-documentation/data-sheets/AD7682_7689.pdf

Can you show me an example with a plot please? Online I found only the definition of pseudo-differential unipolar and other definitions:

http://www.analog.com/media/en/technical-documentation/product-selector-card/2PB_sarinputtypesfb.pdf

Thank you in advance.

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A Pseudo Bipolar signal is just a bipolar signal with a non-zero voltage at which the signal is considered to have zero magnitude. A "true" bipolar signal has 0V as the zero magnitude voltage.

Pseudo Bipolar allows you to use a positive reference voltage and voltage range at the ADC input and generate positive and negative output values, with respect to the reference voltage. This saves having to use a bipolar power supply.

You already have a plot of pseudo bipolar in your second reference. It is just named slightly differently. In this case, the zero magnitude voltage is 2.5V.

enter image description here

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  • \$\begingroup\$ Hello @crj11, in the datasheet there is "pseudobipolar" without the word differential. Is there a pseudobipolar not differential input? \$\endgroup\$ – Gennaro Arguzzi Sep 12 '18 at 8:54
  • \$\begingroup\$ @Gennaro Arguzzi I agree that the terminology is confusing. My take on the difference between differential and non differential is that in the non-differential case, you assume that the reference input is fixed and the other input varies. In the differential case, both inputs vary, but have a non-zero common mode voltage. \$\endgroup\$ – crj11 Sep 12 '18 at 11:32
  • \$\begingroup\$ sorry for the hassle. If I have a single-ended (=non differential) input, the signal can be unipolar or bipolar. Pseudobipolar is difficult to think about. \$\endgroup\$ – Gennaro Arguzzi Sep 12 '18 at 15:16
  • \$\begingroup\$ only now I understood what you said me...Thank you for your good explanation. \$\endgroup\$ – Gennaro Arguzzi Sep 14 '18 at 16:25

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