Accession Number : AD0775807

Title :   An Automatic Scaling Device for Analog Input Signals in a Computer Data Acquisition System.

Descriptive Note : Memorandum rept. (Final),

Corporate Author : BALLISTIC RESEARCH LABS ABERDEEN PROVING GROUND MD

Personal Author(s) : Rocchio,J. J. ; Vogel,E. M.

Report Date : MAR 1974

Pagination or Media Count : 16

Abstract : A device which automatically scales an input signal to an analog to digital converter (ADC) has been developed. It consists of a voltage comparator which, depending on the signal level, switches to one of two operational amplifier inputs having a gain of one and eight respectively. When the unity gain amplified input is selected a flag is set which signals the computer to multiply the value when read by eight. This extends the dynamic range of a system using a 12 bit ADC (resolution 1 part in 4096) from 4095 to 32760. The benefits are a significant decrease in the dwell time per measurement and the amount of software overhead needed to make a scaled reading of an ADC. Other applications of this technique include automatic presentation of data as a 12 bit magnitude and 3 bit binary exponent which could extend the dynamic range to 524,000. This technique may be extended to an ADC of less than 12 bits resolution and therefore to computers with word lengths less than 16 bits. (Author)

Descriptors :   *MASS SPECTROMETERS, *ANALOG TO DIGITAL CONVERTERS, DATA ACQUISITION, CONTROL SYSTEMS, LOGIC CIRCUITS, SCALERS, MINICOMPUTERS, SIGNAL PROCESSING

Subject Categories : Computer Hardware
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE