5 ms·

How fascinating. I wonder what is the measure of precision on such computers for real numbers. And can this be used for integer math if at all ?

brandmeyer 8y ago
Closest that I've come is working with opamp circuits. Generally speaking: Doing almost anything in analog is more expensive than doing it digitally. These days, the only things you do in analog are things that are impossible to do digitally, like anti-aliasing filters. RF is another story, but even there the economics are changing with direct-sampling ADCs. 1% resistors are easy to find. 0.1% can be found at a high price. 0.01% can also be found, for roughly 1 USD/ea, and only on the E12 sequence. Capacitors are worse by a factor of 5 or so. Those tolerances turn into scale-factor error, common-mode rejection ratio, DC bias, and so on. Without breaking the bank, you can easily build a circuit to maybe 7 bits of accuracy, and for a small timer you can do maybe 12 bits or so. But in volume, its almost always better economically to use a lower-accuracy circuit and perform calibration at the factory or in the field. Aside: I fact-checked myself on Digikey and was pleasantly surprised to find that you can get 0.01% resistors without "calling for quote." A few years ago the limit for small-timers was effectively only about 0.1%. Even still 1 USD/ea is a BOM budget-buster for all but the most narrow of uses.
- esmi 8y ago
  Circuit with an ENOB > 12 definitely exist. See table 1 in the app note below for an example. https://www.maximintegrated.com/en/app-notes/index.mvp/id/5384 https://www.maximintegrated.com/en/app-notes/index.mvp/id/53...
  - brandmeyer 8y ago
    ADC's well above ENOB exist. 24-bit sigma-delta ADC's are pretty easy to come by without breaking the budget. But analog computation circuits (subtraction, gain, addition) are another matter entirely.
    - esmi 8y ago
      Doesn’t one make a sigma delta from subtracting, integration and gain stages? If one could make a sigma delta one could make other stuff too. https://en.m.wikipedia.org/wiki/Delta-sigma_modulation#/media/File%3ABlock_Diagram_Delta-Sigma_ADC(minor_change).svg https://en.m.wikipedia.org/wiki/Delta-sigma_modulation#/medi...
      - brandmeyer 8y ago
        Sigma-delta ADC's are built in such a way that component errors result in changes in bandwidth instead of changes in scale factor.
deleted 8y ago
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brandmeyer 8y ago

Closest that I've come is working with opamp circuits. Generally speaking: Doing almost anything in analog is more expensive than doing it digitally. These days, the only things you do in analog are things that are impossible to do digitally, like anti-aliasing filters. RF is another story, but even there the economics are changing with direct-sampling ADCs. 1% resistors are easy to find. 0.1% can be found at a high price. 0.01% can also be found, for roughly 1 USD/ea, and only on the E12 sequence. Capacitors are worse by a factor of 5 or so. Those tolerances turn into scale-factor error, common-mode rejection ratio, DC bias, and so on. Without breaking the bank, you can easily build a circuit to maybe 7 bits of accuracy, and for a small timer you can do maybe 12 bits or so. But in volume, its almost always better economically to use a lower-accuracy circuit and perform calibration at the factory or in the field. Aside: I fact-checked myself on Digikey and was pleasantly surprised to find that you can get 0.01% resistors without "calling for quote." A few years ago the limit for small-timers was effectively only about 0.1%. Even still 1 USD/ea is a BOM budget-buster for all but the most narrow of uses.

esmi 8y ago
Circuit with an ENOB > 12 definitely exist. See table 1 in the app note below for an example. https://www.maximintegrated.com/en/app-notes/index.mvp/id/5384 https://www.maximintegrated.com/en/app-notes/index.mvp/id/53...
- brandmeyer 8y ago
  ADC's well above ENOB exist. 24-bit sigma-delta ADC's are pretty easy to come by without breaking the budget. But analog computation circuits (subtraction, gain, addition) are another matter entirely.
  - esmi 8y ago
    Doesn’t one make a sigma delta from subtracting, integration and gain stages? If one could make a sigma delta one could make other stuff too. https://en.m.wikipedia.org/wiki/Delta-sigma_modulation#/media/File%3ABlock_Diagram_Delta-Sigma_ADC(minor_change).svg https://en.m.wikipedia.org/wiki/Delta-sigma_modulation#/medi...
    - brandmeyer 8y ago
      Sigma-delta ADC's are built in such a way that component errors result in changes in bandwidth instead of changes in scale factor.

deleted 8y ago

[deleted]