Monolithic isolated gate FET saw signal processor

Claim 2

A surface acoustic wave signal processing module comprising a piezoelectric and semiconductive substrate with means for launching a pair of acoustoelectric waves in said substrate along a propagation path adjacent to a surface of said substrate and a plurality of taps disposed on said surface along said propagation path, each of said taps including at least one drain electrode having an ohmic contact with said substrate, the drain electrodes of all of the taps being connected together, a gate electrode having a rectifying contact with said substrate, the gate electrode of each tap being totally ohmically isolated, and at least one source electrode having an ohmic contact with said substrate, the source electrodes of all the taps being connected together.

Claim 3

In a method of correlating amplitude and/or phase coded signals by means employing a surface acoustic wave module in which the temporal extent of the coded waves is much greater than the propagation delay time of the surface acoustic wave module, the steps of: launching a pair of waves into a surface acoustic wave module comprising a piezoelectric and semiconductive substrate having a plurality of taps disposed on the surface along a propagation path between wave launching transducers, each of said taps including at least one drain electrode having an ohmic contact with said substrate, the drain electrodes of all of the taps being connected together, a gate electrode having a rectifying contact with said substrate, the gate electrode of each tap being totally ohmically isolated, and at least one source electrode having an ohmic contact with said substrate, the source electrodes of all the taps being connected together, said wave being launched in relation with each other so as to achieve coincidence of like coding at one tap within said substrate, one of said waves being a signal to be correlated with the other of said waves which comprises a reference wave having the desired coding and the same frequency as the signal to be correlated; biasing said taps by providing a bias voltage between said common sources and said common drains, said bias voltage being applied during the time that said waves are interacting in said module, said bias voltage being such as will provide an electric field beneath each of the taps to induce a significant amount of nonlinear product mixing of said waves, one of the components of which is a standing wave, consisting of a steady state electric field at each tap corresponding with each component of the waves being correlated, such that only a tap having components of both waves thereat continuously in code coincidence as the two waves pass beneath said tap are additive; after the two launched signal and reference waves have subsided in said substrate, launching a carrier wave in said substrate at a first frequency, and thereafter launching an RF pulse in said substrate at a second frequency, said pulse having a duration substantially related to the propagation delay of waves across a single tap of said substrate, said carrier wave having a duration at least twice as great as the total propagation delay of waves through said substrate, said pulse being launched in timed relationship with said carrier wave so that said pulse will mix with said carrier wave at substantially all of said taps with mixing strength at any of the taps determined by the charge buildup occurring during said launching and biasing steps; and extracting from all of said common sources and drains a signal which indicates the mixer efficiency at each of said taps by the amplitude of such signal at a third frequency which is selected from the sum and difference of the frequencies of said carrier and said pulse.

Claim 4

In a method of correlating amplitude and/or phase coded signals by means employing a surface acoustic wave module in which the temporal extent of the coded waves is much greater than the propagation delay time of the surface acoustic wave module, the steps of: launching a pair of waves into a surface acoustic wave module comprising a piezoelectric and semiconductive substrate having a plurality of taps disposed on the surface along a propagation path between wave launching transducers, each of said taps including at least one drain electrode having an ohmic contact with said substrate, the drain electrodes of all of the taps being connected together, a gate electrode having a rectifying contact with said substrate, the gate electrode of each tap being totally ohmically isolated, and at least one source electrode having an ohmic contact with said substrate, the source electrodes of all the taps being connected together, said wave being launched in relation with each other so as to achieve coincidence of like coding at one tap within said substrate, one of said waves being a signal to be correlated with the other of said waves which comprises a reference wave having the desired coding and the same frequency as the signal to be correlated; biasing said taps by providing a bias voltage between said common sources and said common drains, said bias voltage being applied during the time that said waves are interacting in said module, said bias voltage being such as will provide an electric field beneath each of the taps to induce a significant amount of nonlinear product mixing of said waves, one of the components of which is a standing wave, consisting of a steady state electric field at each tap corresponding with each component of the waves being correlated, such that only a tap having components of both waves thereat continuously in code coincidence as the two waves pass beneath said tap are additive; after the two launched signal and reference waves have subsided in said substrate, launching a carrier wave in said substrate at a first frequency, and thereafter launching an RF pulse in said substrate at a second frequency, said pulse having a duration substantially related to the propagation delay of waves across a single tap of said substrate, said carrier wave having a duration at least twice as great as the total propagation delay of waves through said substrate, said pulse being launched in timed relationship with said carrier wave so that said pulse will mix with said carrier wave at substantially all of said taps with mixing strength at any of the taps determined by the charge buildup occurring during said launching and biasing steps; and extracting from all of said common sources and drains a signal which indicates the mixer efficiency at each of said taps by the amplitude of such signal at a third frequency which is selected from the sum and difference of the frequencies of said carrier and said pulse.