Circuit provides output signal with sinusoidal function in response to bipolar transition of input signal. Instantaneous transition shapes into linear rate of change and linear rate of change shapes into sinusoidal rate of change. Circuit contains only active components; therefore, compatibility with integrated circuit techniques is assured

Harper, T. P.

English

NASA Technical Reports Server

November 1971	 Brief 71-10429 
S
NASA TECH BRIEF 
Marshall Space Flight Center 	 A 
NASA Tech Briefs announce new 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. 
Waveshaping Electronic Circuit 
T First Stage-
	
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Elhfrd Stage - - - 
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11	 Logic N	 - 
The problem: 
Spurious sideband components generated in signal 
modulating systems cause interference to adjacent 
frequency channels. Premodulation pulse train filters 
which employ LC filters to suppress the unwanted 
sidebands are usually designed for symmetrical wave-
forms and specific bandwidths. The physical charac-
teristics of the LC components limit the degree of 
application to integrated circuit fabrication tech-
n iques.
The solution: 
A four-stage waveshaping circuit provides an 
output signal with a sinusoidal function in response 
to a bipolar transition of an input signal. The cir-
cuit shapes the instantaneous transition into a linear 
rate of change, and subsequently shapes the linear 
rate of change into a sinusoidal rate of change. Be-
cause the circuit contains only active components 
(inductive elements are eliminated), compatibility 
with integrated circuit techniques is assured. 
Ah
(con irlued overleaf) 
qW
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 ownedrights.
https://ntrs.nasa.gov/search.jsp?R=19710000426 2020-03-17T02:30:59+00:00Z
How it's done: 
The first stage of the circuit is composed of an 
operational amplifier and feedback circuit, and pro-
duces an output signal with a linear rate of change 
in response to the instantaneous transition of the 
input signal. The second stage provides further 
waveshaping to the bipolar output signal from the 
first stage. When the first stage output signal 
undergoes a linear rate of transition from one out-
put level to another level of opposite polarity, the 
second stage provides an opposite-phase bipolar 
signal with a transition having a sinusoidal rate of 
change. The exclusive connection of the first and 
second stages effectively reduces the bandwidth of 
the input signal pulses, and thereby of its accompany-
ing spurious sideband components. 
The third stage generates an output signal which 
has a sinusoidal rate of change and a predetermined 
harmonic content. The harmonic content may be 
preselected at anywhere from 0 to 100%. 
The fourth stage is composed of feedback ca-
pacitors and a selective switching matrix. When 
coupled to the first input stage, the capacitor feed-
back shapes the output signal with a predetermined 
slope characteristic. 
Note: 
No further documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Code A&TS-TU 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B71-10429 
Patent status: 
No patent action is contemplated by NASA. 
Source: T.P. Harper of

IBM Corp.
under contract to

Marshall Space Flight Center

(M FS-14916)
is 
Brief 71-10429
	 Category 01


Waveshaping electronic circuit

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