Abstract: An improved manufacturing technique for producing a certain class of Surf Acoustic Wave (SAW) devices, namely those having input and output transducers in close proximity. A much higher manufacturing yield results from eliminating the cutting of a slot in the substrate between input and output transducers as formerly done. This frequently destructive step is replaced by ion-milling of a deep groove between the ports and backfilling with a metal of proper configuration to provide elecromagnetic shielding. The technique produces a new device that is at least equal to the prior art in rejection of unwanted couplings between input and output.

Abstract: The invention is an improved manufacturing technique for producing a certain class of Surface Acoustic Wave (SAW) devices, namely those having input and output transducers in close proximity. A much higher manufacturing yield results from eliminating the cutting of a slot in the substrate between input and output transducers as formerly done. This frequently destructive step is replaced by ion-milling of a deep groove between the ports and backfilling with a metal of proper configuration to provide electromagnetic shielding. The technique produces a new device that is at least equal to the prior art in rejection of unwanted couplings between input and output.

Abstract: An acceleration resistant crystal features two crystals mounted together h at least two axes of each crystal being in antiparallel relationship with respect to corresponding axes of the other crystals. The two crystals can be chiral pairs and thus have three corresponding axes in antiparallel relationship for acceleration resistance in any arbitrary direction with respect to the crystal axes.

Abstract: A method and apparatus for determining anomalies in the frequency- or admittance-temperature characteristic of a piezoelectric crystal resonator by inserting a variable capacitance network in series with the crystal and electronically sweeping the value of the capacitance network by a control voltage applied thereto while the temperature remains constant and noting any abrupt change in the resonance frequency characteristic.