Abstract: A ranging system employing a limiting constant false alarm rate (CFAR) receiver having reduced recognition time uncertainty, or recognition jitter. The jitter is made proportional to signal-to-noise ratio by providing the receiver with a two-part signal. A conditioning signal is provided to the receiver prior to the time the receiver is expected to sense and respond to a recognition signal for ranging. The conditioning signal has selected strength and duration sufficient to suppress noise to a desired extent in the receiver at the time the recognition signal is received. The combination of strength and frequency of the conditioning signal is selected so as to limit the probability of a false alarm, or undesired recognition of the conditioning signal in the receiver. Receiver modification is not required.

Abstract: A rolling toy in substantially permanently assembled form including a body having retaining apertures therein receiving mounting blocks in fastened relation. The blocks include tubular axle members rotatably receiving individual wheels, the latter being held assembled by hub members having shafts received in the tubular axle members. Coupling means integral with the body allows serial connecting of plural toys. Mounting means may be provided on the body to detachably hold other parts thereon.