Self-Biased Amplitude-Controlled Oscillator With Constant Harmonic Content

Description

Oscillators are described that have a highly stable output frequency versus the variation of supply voltage and different operating conditions such as temperature. The concepts are broadly applicable to various types of oscillators. The highly stable output is achieved with the use of self biasing loops. The circuits associated with providing constant harmonic output current can be used with the concept of a phi-null oscillator to further stabilize the output frequency.

Aspects

An objective is to minimize the impact of harmonics on the stability of the output frequency of oscillators. The present inventors have found that even at relatively low and constant oscillation amplitudes achieved in AAC controlled oscillators, the harmonic content has an appreciable impact on the stability of the output frequency of the AAC controlled oscillators. The present inventors have further found that the problem lies in the variation of the operating bias point of the active Gm cell across the different operating conditions. Thus, the harmonic content varies, and in turn the output frequency varies.

Status

Patented

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