The Himark RX3310A is a superheterodyne receiver. It is also used in the CM15A.
Most X10 modules are powered that way (CM15A has a transformer). It's a cheap, transformerless capacitive power supply.
I may have a KR15A in my
junk box of older X10 modules. If so, I also have a new USB 'scope I've yet to setup and try - this may be fun to track down.