Automatic Digital Noise Checker determines the noise content of the many analog imputs of a data acquisition system and whether the Electronic Calibrations /EC/ on some data channels are operating properly

Harrold, J. L.

Weegmann, C. F.

English

NASA Technical Reports Server

November 1967
	 Brief 67-10467 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Automatic Testing Device Facilitates Noise Checks and

Electronic Calibrations 
The problem: 
To design an automatic testing device that will (1) 
determine the noise content of the many analog inputs 
of a data acquisition system and (2) determine whether 
the electronic calibrations (EC) on some data chan-
nels are operating properly. The two checks, Noise 
and EC, were previously accomplished under manual 
control using a digital to analog converter and a 
storage type oscilloscope. The Noise check had to be 
accomplished on anywhere from 50 individual chan-
nels to a maximum capacity of 400 individual channels 
depending on the test. The EC check had to be made 
on all channels that were expected to provide cali-
bration data for data reduction use. The number of 
channels providing EC data can typically range from 
approximately 30 to 150 channels. This method of 
checking necessitated several operators, was very 
time consuming, and required a good deal of judg-
ment on the part of the operators. 
The solution: 
An automatic Digital Noise Checker that performs 
the following: 
I. Operates on-line using real time data. 
2. Operates off-line using prerecorded check data. 
3. Utilizes digital data rather than reconstructed 
analog data. 
4. Sequences automatically through all system chan-
nels. 
Prints on paper the channel, noise content, and a 
representative data value occurring in a number of 
samples for a Noise check. 
Prints on paper the channels that EC in a prede-
termined selectable region for an EC check.
How it's done: 
The Digital Noise Checker consists of four digital 
logic chassis, a control panel, a printer, and power 
supplies. The operation of the unit is set up to ac-
commodate four operating modes. Modes I and 4 are 
provided for automatic Noise checks, Mode 2 is pro-
vided for the EC check. Mode 3 provides a multiplexer 
pattern sorting capability for the data acquisition 
system. The unit can accept inputs from either of two 
data acquisition recording systems by switch selection. 
The unit uses a theory of limits to accomplish its 
tasks. The unit monitors the data samples from a 
single channel until the number of preselected 
samples have occurred and then advances control to 
monitor the data samples from the next channel that 
is sampled by the data acquisition system. The process 
is continued until all channels that are sampled have 
been monitored. Each time monitoring is completed 
for a channel, the results are printed, if printing is 
required by the processing, and manually selectable 
print options are available. 
Notes: 
I. It is anticipated that this unit will be used for the 
following: 
a. Perform Noise checks with results for all chan-
nels containing flags for noise levels above pre-
determined selected limits. 
b. Perform EC checks with a printout of the chan-
nels that have data falling within a predeter-
mined selectable region. 
c. Sort multiplexer patterns for system setup use. 
d. Perform channel data histograms by printing 
out periodic data samples for a selected chan-
nel. 
i
n(continued overleaf) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19670000467 2020-03-11T20:54:47+00:00Z
e. Perform zero drift tests by printing out data 
values for all channels for reeafe7J -calibrate 
inputs. 
f. Perform gain stability tests by printing out 
data values for all channels for repeated cali-
brate inputs. 
2. Inquiries concerning this invention may be di-
rected to:
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: B67-10467
Patent status: 
Inquiries about Dbtaining rights for the commercial 
use of this invention má3' be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: Joseph L. Harrold 
and Carl F. Weegmann
(LEW- 10173)
.. 
. 
Brief 67-10467
	 Category 01


Automatic testing device facilitates noise checks and electronic calibrations

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