Non-linear signal processing device using square law detection of surface elastic waves with insulated gate field effect transistor

Claim 1

A system for the non-linear mixing of acoustic waves comprising: a. a substrate, b. means for launching said acoustic waves in said substrate, so that said acoustic waves propagate through a defined region of said substrate simultaneously, and c. an IGFET formed at the surface of said substrate so that at each point along the channel of said IGFET, a component of the incremental channel current is proportional to the square of the sum of the strains induced by said acoustic waves in said substrate and the total channel current of said IGFET is the sum of said incremental channel currents.

Claim 2

A system for the non-linear mixing of acoustic waves comprising: a. a substrate, b. means for launching said acoustic waves in said substrate, so that said acoustic waves propagate through a defined region of said substrate simultaneously, and c. an IGFET formed at the surface of said substrate so that at each point along the channel of said IGFET, a component of the incremental channel current is proportional to the square of the sum of the strains induced by said acoustic waves in said substrate and the total channel current of said IGFET is the sum of said incremental channel currents.

Claim 3

A system for performing the acoustic convolution of two signals comprising: a. a substrate capable of supporting the propagation of acoustic surface waves, b. interdigital transducers located on the surface of said substrate for launching acoustic surface waves representative of said signals, said acoustic surface waves being caused to propagate in opposite directions and to pass in a defined region intermediate to said interdigital transducers, and c. an IGFET located at the surface of said substrate and intermediate to said interdigital transducers such that strains in said defined region are coupled to the channel region of said IGFET, and at each point in said channel region a component of the incremental channel current is proportional to the square of the sum of the strains induced by said acoustic surface waves at said point and wherein the total channel current of said IGFET is the sum of said incremental channel currents.

Claim 4

A system for performing the acoustic convolution of two signals comprising: a. a substrate capable of supporting the propagation of acoustic surface waves, b. interdigital transducers located on the surface of said substrate for launching acoustic surface waves representative of said signals, said acoustic surface waves being caused to propagate in opposite directions and to pass in a defined region intermediate to said interdigital transducers, and c. an IGFET located at the surface of said substrate and intermediate to said interdigital transducers such that strains in said defined region are coupled to the channel region of said IGFET, and at each point in said channel region a component of the incremental channel current is proportional to the square of the sum of the strains induced by said acoustic surface waves at said point and wherein the total channel current of said IGFET is the sum of said incremental channel currents.

Claim 5

A method of performing the acoustic convolution of two signals including the steps of: a. launching contra-directed acoustic surface waves representative of said two signals on a surface wave delay line, such that said acoustic surface waves propagate simultaneously through the channel of an IGFET formed at the surface of said surface wave delay line, b. developing a voltage proportional to the drain current of said IGFET, and c. filtering said voltage so as to extract the component of said voltage representative of said acoustic convolution.

Claim 6

A method of performing the acoustic convolution of two signals including the steps of: a. launching contra-directed acoustic surface waves representative of said two signals on a surface wave delay line, such that said acoustic surface waves propagate simultaneously through the channel of an IGFET formed at the surface of said surface wave delay line, b. developing a voltage proportional to the drain current of said IGFET, and c. filtering said voltage so as to extract the component of said voltage representative of said acoustic convolution.

Claim 7

A system for the non-linear mixing of acoustic surface waves comprising: a. a substrate, b. means for launching acoustic surface waves from opposite ends of said substrate in said substrate so that said acoustic surface waves propagate through an intermediate region of said substrate simultaneously in opposite directions, c. a semiconductor film of piezoelectric material disposed on said substrate and overlying said intermediate region thereof, said semiconductor film having a plurality of distinct regions extending lengthwise thereof in line with the propagation directions to be assumed by said acoustic surface waves, said plurality of distinct regions including a pair of spaced apart outer regions of one conductivity type and a channel region of the other conductivity type interposed between said pair of outer regions and connecting said pair of outer regions, d. an insulating layer overlying said semiconductor film and covering said channel region thereof, and e. a gate electrode disposed on said insulating layer, f. said semiconductor film, said insulating layer, and said gate electrode cooperating to define an IGFET structure wherein said pair of outer regions comprise the source and drain regions and said channel region is coextensive with said intermediate region of said substrate, and g. said IGFET structure being responsive to the simultaneous propagation of acoustic surface waves in said substrate in opposite directions such that at each point along said channel region an incremental channel current is produced having a component proportional to the square of the sum of the strains induced by said acoustic surface waves at said point to provide a total channel current for said IGFET structure which is the sum of said incremental channel currents.

Claim 8

A system for the non-linear mixing of acoustic surface waves comprising: a. a substrate, b. means for launching acoustic surface waves from opposite ends of said substrate in said substrate so that said acoustic surface waves propagate through an intermediate region of said substrate simultaneously in opposite directions, c. a semiconductor film of piezoelectric material disposed on said substrate and overlying said intermediate region thereof, said semiconductor film having a plurality of distinct regions extending lengthwise thereof in line with the propagation directions to be assumed by said acoustic surface waves, said plurality of distinct regions including a pair of spaced apart outer regions of one conductivity type and a channel region of the other conductivity type interposed between said pair of outer regions and connecting said pair of outer regions, d. an insulating layer overlying said semiconductor film and covering said channel region thereof, and e. a gate electrode disposed on said insulating layer, f. said semiconductor film, said insulating layer, and said gate electrode cooperating to define an IGFET structure wherein said pair of outer regions comprise the source and drain regions and said channel region is coextensive with said intermediate region of said substrate, and g. said IGFET structure being responsive to the simultaneous propagation of acoustic surface waves in said substrate in opposite directions such that at each point along said channel region an incremental channel current is produced having a component proportional to the square of the sum of the strains induced by said acoustic surface waves at said point to provide a total channel current for said IGFET structure which is the sum of said incremental channel currents.