Silicon Laboratories Inc.
Noise canceling technique for a sine to square wave converter

Abstract:

A sine to square wave converter circuit receives a sine wave signal and supplies a first square wave signal having a first frequency. A 2.times. clock multiplier circuit multiplies the first square wave signal and supplies a second square wave signal with a second frequency that is twice the first frequency. A first storage element that is clocked by the second square wave signal stores a delayed version of the first square wave signal and supplies an even-odd signal. A second storage element that is clocked by the second square wave signal receives the even-odd signal and supplies an odd-even signal. A duty cycle correction circuit adjusts the threshold of the sine to square wave converter based on a difference in duty pulse widths between the even-odd signal and the odd-even signal.