with indication presented on cathode-ray tubes

Full Title

Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic or electromagnetic waves, or particle emission, not having a directional significance, are being received > using ultrasonic, sonic or infrasonic waves > with indication presented on cathode-ray tubes

Classification Context

Section:

PHYSICS

Class:

MEASURING; TESTING

Subclass:

RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES