Browse Prior Art Database

METHOD TO REDUCE RFI IN A CMOS PIERCE CRYSTAL OSCILLATOR

IP.com Disclosure Number: IPCOM000005894D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2001-Nov-14
Document File: 1 page(s) / 37K

Publishing Venue

Motorola

Related People

Kenneth R. Burch: AUTHOR

Abstract

This method reduces the Radio Frequency Interference (RFI) produced by CMOS Pierce crystal oscillators.

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MOTOROLA Technical Developments Volume 10 March 1990

METHOD TO REDUCE RFI IN A CMOS PIERCE CRYSTAL OSCILLATOR

by Kenneth R. Burch

ABSTRACT: This method reduces the Radio Frequency Interference (RFI) produced by CMOS Pierce crystal oscillators.

   The output signal waveform at the output of a CMOS Pierce crystal oscillator is often nearly "square". Thus the harmonic content is quite high. These undesired frequency components can cause interference in nearby radio circuits. The level of RFI can be reduced significantly by lowering the large signal loop gain by using a variation of the conven- tional CMOS Pierce circuit.

REF 125mV MARKER 3 4800 000.0 Hz 10 dB/DIV RANGE 125 mV 125 mV

START .O Hz STOP 40 000.0 Hz

RBW 30 KHz VBW 30 KHz ST 51.2 SEC

REF 125mV MARKER 3 4800 DOD.0 Hz 10 dEf/DIV RANGE 125 mV 86 mV

START .O Hz STOP 40 000.0 Hz

RBW 30 KHz VBW 30 KHz ST 51.2 SEC

0 Motorola, Inc. 1990

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