Diode generator using four building-block circuits produces complex waveforms without the necessity of series summation. This highly specialized method of producing complex waveforms requires less power than present methods and uses simpler circuitry

Callan, J. D.

Mc Call, A. J.

Mead, D.

English

NASA Technical Reports Server

Lesser-Taker
0)4	 -o 
0)4 ASin 
V=A/2 
Level-Shifter	 .	 p
—A Sin 
Vz. = A
V
Dutput 
r Cos[27r Sin w t] 
August 1966
	 Brief 66-10351 
NASA TECH BRIEF 
- - -	 -	 - 
NASA Tech Briefs are issued to summarize specific innovations derived from the U. S. space 
program and to encourage their commercial application. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Function Generator Eliminates Necessity of Series Summation 
Greater-Taker 
Diode-Shaper 
+VD 
The problem: 
To produce complex waveforms electronically with-
out the necessity of series summation. 
The solution: 
A diode generator that produces functions of such 
complexity as sin(27rsinwt) and cos(2rsinwt) at 
frequencies down to zero cycles per second, using the 
combined outputs of four basic circuits. 
How it's done: 
This generator uses four building-block circuits to 
produce complex waveforms without the necessity of 
mathematically reducing the desired function to a
(continued overleaf) 
series, and then summing the outputs produced by 
circuits generating the waveforms represented by the 
individual series elements. 
Each of the four circuits alters the input signals 
in a particular way. One takes the greater part of 
both input signals (greater-taker), one takes the 
lesser part of both signals (lesser-taker), one splits 
the positive input into a positive and negative signal 
of the same waveshape (level-shifter), and one rounds 
off the top of the positive input (diode-shaper). For 
example, in the circuit diagram shown for the develop-
ment of the function of cos(21rsinwt), the circuits are 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights:
https://ntrs.nasa.gov/search.jsp?R=19660000350 2020-03-11T17:41:19+00:00Z
so connected that the characteristic input waveshapes 
of Asinwt at point a and —Asinwt at point b are modi-
fied sequentially by each circuit to result in an output 
waveform that very closely approximates the desired 
function. 
The four basic circuits can be connected in various 
ways to produce the same waveform. They are suf-
ficiently flexible that some resistors can be eliminated, 
some diodes can be replaced by emitter-follower 
transistor configurations, and the number of compo-
nents in the diode-shaper can be varied, depending on 
the particular application of the generator. There are 
also combinations of circuits in which the forward 
voltage drops of the greater- and lesser-taker diodes 
are compensated by using two diodes where func-
tionally only one is required. 
Notes: 
1. This highly specialized method of producing com-
plex waveforms requires less power than present 
methods and uses simpler circuitry.
2. Many functions other than those indicated here can 
be implemented by an empirical synthesis of the 
same building-block circuits. 
3. Inquiries concerning this invention may be di-
rected to:
Technology Utilization Officer 
Goddard Space Flight Center 
Greenbelt, Maryland 20771 
Reference: B66-10351 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: David Mead, A. Joseph McCall,

and J. David Callan

of Hughes Aircraft Co.

under contract to

Goddard Space Flight Center
(GSFC-2 14) 
Brief 66-10351	 Category 01


Function generator eliminates necessity of series summation

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server