The circuit shown is from National Semiconductor's Linear Applications Handbook. It makes use of the LM78S40 which is not an easy component to obtain today.
A The adjustable Q-factor rejector filter in the figure is based on two LM110. These integrated...
This circuit can be powered by a voltage of only 2.5 V. Next to the diagram we have the formulas...
This circuit with a supply voltage of only 2.5 V was found in a 2005 Linear Technology...