In the figure we have a way of receiving ultrasonic signals of a single frequency using a PLL 567. The circuit is from Radio Electronics from November 1985.
The oscillator shown in the figure generates a rectangular signal with a 50% active cycle (square)...
This power supply can be implemented with a TIP32 providing an adjustable output at the 2k2...
This switched circuit was found in an old documentation and no information about the transformer...