US 5,686,917 A · System and method for demultiplexing data in an instrumentation system

Abstract

An instrumentation system according to the present invention which automatically demultiplexes multiplexed data received from multiple analog channels. The system includes a plurality N of analog channels that are multiplexed into an A/D converter. The A/D converter in turn supplies the multiplexed or interleaved digital data to an external computer where the data is stored in memory. The external computer includes direct memory access (DMA) demultiplexing logic according to the present invention which automatically reads the multiplexed data and rewrites the multiplexed data into a non-interleaved or demultiplexed format. Once all the multiplexed digital data has been received and stored in the computer system, the demultiplexing logic of the present invention performs DMA transfers to demultiplex or de-interleave the data into N independent buffers or memory spaces which are no longer interleaved. The DMA multiplexing logic performs a transfer for each analog channel to split the data for each analog channel into separate buffers. The DMA demultiplexing logic performs each transfer by incrementing through addresses of the multiplexed data to transfer only the data corresponding to a respective analog channel. The demultiplexing logic increments by the transfer size and an address sequencing value which is the number of analog channels of data in the multiplexed data. In other words, the DMA demultiplexing logic sequences a multiple N times the transfer size, wherein the multiple N is the number of analog channels of interleaved data received by the computer system.

Claims15

Dependent claims

A method for performing data acquisition in an instrumentation system comprising a plurality N of analog channels, analog to digital conversion logic coupled to said plurality N of analog channels, memory coupled to said analog to digital conversion logic and direct memory access demultiplexing logic coupled to the analog to digital conversion logic and the memory, the method comprising the steps of:

receiving analog data from said plurality N of analog channels;
performing analog to digital conversion on said analog data;
multiplexing said data from said plurality N of analog channels into one or more multiplexed digital data streams;
storing said multiplexed digital data in the memory;
activating said direct memory access demultiplexing logic;
and
transferring portions of said multiplexed digital data corresponding to respective ones of said plurality N of channels to respective new locations in said memory, wherein said portions of said multiplexed data corresponding to respective ones of said plurality of N channels are stored in respective separate address spaces in said memory.

4 more elements

An instrumentation system which automatically demultiplexes acquired multiplexed data, comprising:

a plurality N of analog channels;
multiplexing logic coupled to said plurality N of analog channels which multiplexes data from said plurality N of analog channels to produce a single data stream;
analog to digital conversion logic coupled to said plurality N of analog channels which performs analog to digital conversion on data from said analog channels;
memory coupled to said analog to digital conversion logic which stores multiplexed digital data output from said analog to digital conversion logic and said multiplexing logic;
and
direct memory access demultiplexing logic coupled to said analog to digital conversion logic, said multiplexing logic, and the memory, wherein said direct memory access demultiplexing logic transfers portions of said multiplexed digital data corresponding to respective ones of said plurality N of channels to respective new locations in said memory, wherein said portions of said multiplexed data corresponding to respective ones of said plurality of N channels are stored in respective separate address spaces in said memory.

3 more elements

Dependencies are inferred from the claim text.

System and method for demultiplexing data in an instrumentation system

Life of this patent

System and method for demultiplexing data in an instrumentation system

Life of this patent

Abstract

Claims15