Abstract: A Doppler position locator for determining the bearing of a signal source from a moving receiver. The signal source encodes a digital signal indicating its actual transmitting frequency on a transmitted carrier. The moving receiver such as an airplane receives a Doppler shifted carrier frequency and the digital information on what the actual transmitted frequency was. Comparison of the received frequency to the digital information on the transmitted frequency yields a Doppler frequency (the increase or decrease caused by the relative motion, i.e., the numerical difference between the transmitted and received frequencies). From the aircraft velocity and the two frequencies, the bearing can be determined using the formula .crclbar.=cos.sup.-1 (d*c)/(f*v) where .crclbar. is the bearing angle, f is the transmitted frequency, d is the Doppler shift or change in frequency, c is the speed of light and v is the magnitude of the receiver velocity.

Abstract: A solid state electronic alarm circuit including means for sensing a predetermined change in a parameter such as the temperature in a freezer or the like from a predetermined safe limit and means for generating an audible alarm in response thereto.

Abstract: Disclosed is an energy conserving thermostatic control for use wih heating and/or air conditioning systems. The control includes solid state circuitry for automatically controlling or regulating the temperature of an area at at least two different selected temperatures at selected times and for selected periods. The control is compatible with conventional heating and/or air conditioning systems and in most instances can be installed therewith without modification or rewiring of the system.