By Topic

A new type of balanced-bridge controlled oscillator

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

1 Author(s)
Karlquist, R.K. ; Agilent Lab., Palo Alto, CA, USA

A novel bridge-controlled crystal oscillator circuit with exceptional temperature stability is described. The contribution to the oscillator temperature coefficient of frequency (tempco) from the circuit components (exclusive of the crystal) is reduced to about 10/sup -11///spl deg/C, which is several orders of magnitude better than conventional oscillator circuits. This avoids a situation in which the overall tempco is limited by circuit component drift rather than crystal stability, which can easily occur with conventional circuits when the crystal is ovenized at a turnover point. Previous attempts to use a bridge in an oscillator were made by Meacham (1938), who used an imperfectly balanced bridge, and Sulzer (1955), who used a balanced pseudo-bridge. The reasons why these are unsatisfactory are discussed. Although the bridge greatly reduces reactive frequency pulling, it does not address directly the additional issue of pulling caused by variations in crystal drive current amplitude. However, it is an enabling technology for a novel ALC circuit with greatly improved stability. The new bridge-controlled oscillator is also much less sensitive to other environmental effects such as humidity (2/spl times/10/sup -11/, 5%/25% R.H. @70/spl deg/C), power supply voltage, load impedance, and stray capacitance.

Published in:

Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on  (Volume:47 ,  Issue: 2 )