What limits the maximum sampling rate of the analog inputs?
The analog inputs are based on Maxim’s MAX197 DAS chip. This device, using the on-board 2mhz crystal clock, can perform one (internally self-timed)acquisition/conversion on a single channel in about 9us (the reciprocal of which yields the 100ksps specification). However, several other issues must be considered when determining the actual maximum sampling rate a particular application can achieve. In general, the maximum sampling rate for any one channel is inversely proportional to the number of channels being used. To avoid data loss, the result of each conversion must be read and stored before a new conversion can be started. The overall time taken by the host to respond, read the result, store the result and initiate a new conversion must be added to the basic acquisition/conversion time. In addition, a certain variability exists in the host’s response time due to interrupt latency and its involvement in other tasks. Using a fast computer will help achieve the highest sampling rate.
