Abstract: The inherent temperature instability of surface acoustic wave (SAW) clock oscillators is improved by the use of a thermometer oscillator circuit that senses temperature changes in the SAW substrate. The thermometer oscillator is used in combination with a calibrated programmable read only memory and a logic circuit and provides frequency corrections to the clock oscillator. The basic device is an oscillator clock circuit using a SAW substrate having a delay path orientation with good temperature stability. A second oscillator, the thermometer oscillator circuit, and the electronic compensation scheme are added in order to produce minimum temperature coefficient of delay over all temperatures in the range of interest. The thermometer oscillator delay path utilizes a high temperature coefficient of delay orientation of the same SAW substrate and at an appropriate angle to the clock oscillator delay path orientation.

Abstract: A broad bandwidth surface acoustic wave filter utilizing two broadband surface acoustic wave transducer pairs which individually comprise a single input and output. One pair of broadband surface acoustic wave (SAW) transducers is offset in frequency from a second pair of broadband SAW transducers. Each transducer is tuned with a single series inductor, and then both channels are connected electrically in parallel. The low frequency pair of transducers is tuned for maximum response below their synchronous frequency, and the high frequency pair of transducers is tuned for maximum response above their synchronous frequency.