Compact, light-weight, solid-state test set can be used to check signal conditioning modules while they are installed in system. Test sets may also be used to cycle ground computer, if it is suspected of malfunctioning, rather than using signal conditioners

Houck, W. H.

Stiberg, J. D.

English

NASA Technical Reports Server

NASA TECH BRIEF 
John F Kennedy Space Center El S
.
28 V Auxilary
Input
June 1973
	
B73-10189 
NASA Tech Briefs announce now technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Signal Conditioner Test Set 
The problem: 
To check signal conditioners it is often necessary to 
remove them from the overall system; in some cases, 
they must be shipped to a laboratory for testing 
and study. 
The solution: 
A compact, light-weight, solid-state test set can be 
used to check signal conditioning modules while they 
are installed in the system.
How it's done: 
The test set, which operates from 115 Vac or 28 
Vdc, indicates whether the signal conditioner is per-
forming according to specification. In the case of the 
specific conditioner for which the set was designed, it 
indicates the condition of a specific capacitor that is 
subject to malfunction. 
A schematic of the test set is shown in the illustration. 
The set consists of an astable multivibrator with a 
13.33% duty cycle which approximates the signal input 
Test Set Schematic
(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=19730000189 2020-03-17T07:09:23+00:00Z
to the, conditioners in the system. The multivibrator 
oscillator has an "off" voltage of abut 27 volts and an 
"on" voltage of one volt. Any intermediate voltage is 
also possible. The output consists of a variable 'ampli-
tude waveform with logic levels compatible with standard 
conditioning equipment. Several known loads are avail-
able through a multiposition switch on the set. The 
oscillator output goes to a driver stage which feeds the 
signal conditioner under test. 
There are several other controls and adjustments. A 
selector switch determines ac or dc power; although in 
either case 28 Vdc is available at external jacks. One fine 
control adjusts the period of oscillation, another the 
duty cycle, and another adjusts the amplitude of the 
waveform as seen by the signal conditioner. The 
oscillator signal, a straight dc voltage, or no voltage at 
all may be fed to the signal conditioner by means of a 
selector switch In addition to these controls, there is 
a mültipositional load switch which allows the user to 
approximate the actual load as closely as possible. 
Although this test set was designed for a specific 
conditioner, it may be used with any conditioner with 
compatible logic levels by means of external jacks 
provided to feed an input signal, a load for the condi-
tioners, and power if needed. In any case, before using 
the set it may be necessary to adjust the frequency or 
duty cycle if they are critical. 
Another feature Of this test set is that it may be used 
to cycle the ground computer, if it is suspected of 
malfunctioning, rather than to use the signal condi-
tioñers In this case, it may bypass the signal conditioner 
and provide a direct signal for the computer. Alternately, 
the test set feeds signals to the conditioners and from 
there to the ground computer. 
Notes: 
1. The only peripheral equipment needed is an oscillo-
scope. 
2. Requests for further information may be directed 
to:
Technology Utilization Officer 
Kennedy Space Center 
Code AD-PAT 
Kennedy Space Center, Florida 32899 
Reference: B73-10189 
Patent status: 
This invention is owned by NASA and a patent 
application has been filed. Inquiries concerning non-
exclusive or exclusive license for its commercial use 
should be addressed to: 
Patent Counsel 
Kennedy Space Center 
Code AD-PAT 
Kennedy Space Center, Florida 32899 
Source: Walter H. Houck and Jon D. Stigberg
Kennedy Space Center
(KSC-10750)
. 
B73-10189
	
Category 02


Signal conditioner test set

A system was developed for testing components contained in a signal conditioning module with a transistor and capacitor included in a circuit. The system includes a housing with a socket into which the module to be tested is plugged. A test switch is provided for selectively connecting a variable load to either a transistor or capacitor in the circuit for testing the operation. A signal generating circuit is provided for generating signals for use in testing the components of the module

Signal conditioner test set

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