High speed data acquisition system and method

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made to the drawings wherein like structures will be provided with like reference designations.
As indicated earlier, in some instances it is very desirable to optimize a data acquisition system for averaging the data as it is gathered.
Averaging provides several advantages.
First, in a properly designed averaging data acquisition system, less data storage space is required since there is less data to be stored.
The amount of storage required is calculated by Equation (1).
##EQU1## where: Memory Required is in samples; Sampling Rate is in Hz; Test Duration is in seconds.
As shown by Equation (1), the storage requirement is decreased in direct proportion to the number of averages taken with other parameters remaining constant.
Second, when averaging is used the speed at which the storage devices can input and output data can be reduced.
This is because averaged data appears at the storage devices at a reduced rate as expressed by Equation (2).
##EQU2## where: s=memory speed in seconds r=sampling rate in Hz n=number of averages The memory speed parameter provides the requirement for an initial module of memory which is included in the data acquisition system with other modules having the same or lesser speed characteristics.
For a high speed data acquisition system the initial module of memory, also referred to as a buffer, is typically comprised of high speed static random access memory (SRAM) as is known in the art.
For example, in the case of a data acquisition system sampling data at 100 MHz with no averaging the SRAM buffer would need to store data at 10 nanosecond intervals.
If it is necessary to store more than a few million samples the previously available methods and devices require circuit arrangements which are cost prohibitive in the case of many applications.
Conversely, if the same data which was sampled at 100 MHz was averaged 1,000 times before being stored, the memory devices would only be required to store data at 10 microsecond intervals