[time-nuts] Advantages of differential oscillator structures?

wb6bnq wb6bnq at cox.net
Sat Aug 10 05:39:35 EDT 2013


Hi Attila,

I gather you did not fully read the paper ?

In normal CMOS circuits, the higher the oscillator frequency the higher 
the amount of current drawn to reach that higher frequency.  So, the two 
oscillator system was used to keep time and "wake" up the higher 
frequency oscillator (for example the 12.8 MHz) when the radio was in 
operation.  When not in operation just the lower frequency oscillator 
(32 KHz) was used to keep time and provide a "wake" of the 
microprocessor and the higher frequency oscillator needed for the radio 
operation.

This paper presents a circuit topography that allows the low current 
operation at a high frequency (12.8 MHz) thus reducing complexity.  This 
in turn allows the design and manufacture of a radio system using one 
crystal oscillator at a frequency of 12.8 MHz (example in the paper) 
with the low power advantage that previously required two oscillators.

Bill....WB6BNQ


Attila Kinali wrote:

>Hi,
>
>While reading up on oscillator circuits i stumbled over differential
>oscillator structures (see [1] for example). But sofar i have been
>unable to figure out what the exact advantages of a differential
>oscillator strucutre in general are.
>Would someone here be so kind and give me some hints where to look?
>
>Thanks in advance
>
>			Attila Kinali
>
>
>
>[1] "A High-Stability, Ultra-Low-Power Differential Oscillator Circuit
>for Demanding Radio Applications", by David Ruffieux, 2002
>http://www.imec.be/esscirc/ESSCIRC2002/PDFs/C02.01.pdf
>http://www.imec.be/esscirc/ESSCIRC2002/presentations/Slides/C02.01.pdf
>
>
>  
>



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