Sine wave generator for different frequencies
First Claim
1. A sine wave generator composed of digital circuits comprising:
- (a) a high frequency oscillator for generating a square wave output pulse train;
(b) a frequency divider circuit being composed ofa first ripple carry binary counter having a data input and an output, and being symmetrically arranged between positive and negative supply voltage, said data input being connected to said output of said square wave oscillator; and
a second shift register including Johnson-counter stages being symmetrically arranged between positive and negative supply voltage, having a data input, a clock input connected to said output of said binary counter and having parallel outputs, one of said parallel outputs forming an output of said frequency divider network;
(c) a binary shift register being designed as a divide-by-n counter and having m counter stages, wherein m=n/2, said shift register having a clock input connected to said output of said frequency divider circuit and having m outputs each associated with a respective one of said counter stages;
(d) a resistor network being composed of m rated resistors having first and second taps and being arranged in parallel with said first taps connected together, and each of said second taps being connected to a respective one of said outputs of said shift register, wherein the rating of said resistors is such that an k-th resistor associated with the k-th output of said shift register has the value ##EQU5## and wherein k is a positive integer from 1 through m;
R is a reference resistance value;
C=1/2 if m is an odd number; and
C=0 if m is an even number; and
(e) a low-pass filter network having an input and an output, said network input being connected to said commonly connected first taps of said resistors and said network output forming the sine wave signal output of said generator.
1 Assignment
0 Petitions
Accused Products
Abstract
A frequency oscillator for generating a square wave output pulse train is connected via a frequency divider circuit to a binary shift register which is designed as a divide-by-n counter with m counter stages, wherein m=n/2. Each stage is associated with an output. A resistor network is composed of m rated resistors each of which resistors is connected to a respective register output and in common to an input of a low-pass filter network forming the output circuit. The rating of the resistors is such that an k-th resistor associated with the k-th output of the shift register has the value ##EQU1## wherein R is a reference resistance value;
k is a positive integer from 1 through m;
C is 1/2 if m is an odd number; and
C is 0 if m is an even number.
Sine wave forms of different frequencies may be selectively chosen if the frequency divider circuit is provided with parallel inputs which are associated with different dividing ratios and are selectively coupled to the input of the binary shift register.
19 Citations
10 Claims
-
1. A sine wave generator composed of digital circuits comprising:
-
(a) a high frequency oscillator for generating a square wave output pulse train; (b) a frequency divider circuit being composed of a first ripple carry binary counter having a data input and an output, and being symmetrically arranged between positive and negative supply voltage, said data input being connected to said output of said square wave oscillator; and a second shift register including Johnson-counter stages being symmetrically arranged between positive and negative supply voltage, having a data input, a clock input connected to said output of said binary counter and having parallel outputs, one of said parallel outputs forming an output of said frequency divider network; (c) a binary shift register being designed as a divide-by-n counter and having m counter stages, wherein m=n/2, said shift register having a clock input connected to said output of said frequency divider circuit and having m outputs each associated with a respective one of said counter stages; (d) a resistor network being composed of m rated resistors having first and second taps and being arranged in parallel with said first taps connected together, and each of said second taps being connected to a respective one of said outputs of said shift register, wherein the rating of said resistors is such that an k-th resistor associated with the k-th output of said shift register has the value ##EQU5## and wherein k is a positive integer from 1 through m; R is a reference resistance value; C=1/2 if m is an odd number; and C=0 if m is an even number; and (e) a low-pass filter network having an input and an output, said network input being connected to said commonly connected first taps of said resistors and said network output forming the sine wave signal output of said generator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
Specification