Found in Texas Instruments documentation from the 1980s, this circuit applies to digital signal transmission with FSK modulation. The circuit is slow, as it uses period components.
Offset Adjustment on an Amplifier with the LM139 (CB14245E) In the figure we have the way of...
This interesting transistor configuration, which can be seen elsewhere on this website and in this...
This circuit, from a documentation of the 90s, uses unusual operations today, but the...