Assertion: radio's receiver | /r/HasProperty | refined into cheap-to-manufacture design
Facets:
value: by the 1940s
type: TEMPORAL
Source sentences:
text: By the 1940s the superheterodyne AM broadcast receiver was refined into a cheap-to-manufacture design called the "All American Five", because it only used five vacuum tubes: usually a converter (mixer/local oscillator), an IF amplifier, a detector/audio amplifier, audio power amplifier, and a rectifier.