Interfacing to an A/D converter
How does a designer interface a signal source to an A/D converter?
The block diagram below shows the type of operations that need to be performed on an input signal to make it usable to an A/D converter.
Below the image are links to each of the three basic signal processing
operation. These links will go to a knowledgebase of information covering the topic in detail.
This generalized block diagram will work for any input to any A/D. Real world applications, however, may not need all of the signal processing steps, or may be able to
combine functions. The filter and gain stages, for example, can often be combined. The DC offset stage is not needed if the input signal is AC.
The knowledgebase items are independent - there is some discussion of filter gain in the filter section, for example, but the first time designer may want to consider
leaving the functions separate. If cost or component count is an issue, it may be best for a beginning designer to contact Texas Instruments Applications for design
assistance. Texas Instruments applications personnel have dealt with these topics for years - and can often point even experienced designers towards less expensive,
better performing options. Best of all, the advice is free!
Level Shifting a Signal to
Match the Input Level of a Device
Op Amp Circuit Gain Control
Analog Filter Op-amp