Abstract: A sensor involving a housing having a lower orifice to which a primary hose is connected. A secondary hose inside the primary hose is slightly shorter than the primary hose, with these hoses being placed inside a bin for determining fill level. One of two upper orifices in the housing is connected to a supply of air under pressure, with this air normally caused to flow outwardly from one of the hoses. Upon the degree of the fill of the bin being such that the material approaches the remote end of one of the hoses, the air normally flowing from the one hose is caused to be deflected into the remote end of the other of the hoses, causing a pressure increase. This pressure increase is directed through the other upper orifice, for being sensed at remotely located pressure sensing equipment.

Abstract: A digital automatic frequency control circuit for use with a scanning type superheterodyne receiver, such circuit having an input for receiving the output of a related discriminator, and an output for providing an incrementally variable tuning voltage to a related local oscillator. My novel circuit has a search mode and a lock mode, and during the search mode, when the receiver tuning is swept past a pulsed radio signal, the discriminator produces a sequence of voltage output pulses whose polarity for a desired signal will be different from that of the signal's image. My circuit recognizes the polarity relationships of such pulses, and makes use of such information in a highly advantageous manner in order to cause the receiver to enter the lock mode only when the received signal has the correct relationship with the local oscillator, with the image signal thus being ignored.