Browse Prior Art Database

High Frequency Voltage-Controlled Oscillator

IP.com Disclosure Number: IPCOM000103271D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 3 page(s) / 70K

Publishing Venue

IBM

Related People

Chen, YCM: AUTHOR [+5]

Abstract

Disclosed is a new monolithic high frequency voltage controlled oscillator that consists of a temperature and voltage-compensated control voltage generator and a ring type voltage-controlled oscillator.

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This is the abbreviated version, containing approximately 86% of the total text.

High Frequency Voltage-Controlled Oscillator

       Disclosed is a new monolithic high frequency voltage
controlled oscillator that consists of a temperature and
voltage-compensated control voltage generator and a ring type
voltage-controlled oscillator.

      The circuit schematic diagram of the temperature-compensated
control voltage generator is shown in Fig. 1.  The differential error
voltages are fed to the base of transistors Q1 and Q2.  The power
supply voltage and current source base voltage of this control
voltage generator are stabilized and temperature-compensated through
diodes and resistors as shown.

      The voltage control oscillator circuit is unique in that it has
N stages of differential amplifiers, as shown in Fig. 2.  Stages 1
through N are connected in a straightforward manner, but the stage N
output are cross-coupled to the stage 1 inputs.  From stage 1 to
stage N, the signal travels with stage delays until stage N is
reached, the stage N outputs are inverted and connect to stage 1
which completes the oscillation loop.  Oscillation frequency is
determined by the number of stages N and the bias current of
individual differential amplifiers.

      To achieve any high free running frequency without external
manual trim, two VCOs are used.  They are fabricated side by side
very closely, as shown in Fig. 3.  The first one, namely the
reference VCO 1, is locked with the system clock through a
divide-by-K counter and phase detector...