Surface wave preselector

Claim 2

A surface wave preselector comprising: a. piezoelectric base; b. a plurality of interdigital transmitter grids deposited on said base, each of said grids adapted to receive an input signal and generate a surface wave in response to a selected frequency of said input signal; c. a plurality of interdigital receiver grids deposited on said base, each of said grids being adapted to receive a surface wave of selected frequency transmitted in said base by a transmitter grid and produce an output signal in response thereto, each of said receiver grids being positioned opposite from an associated transmitter grid, and wherein said transmitter and receiver grids each includes a plurality of electrodes having widths and spaces therebetween in accordance with the following general formula? wm v/4 (1/f1 + (m-1) delta f), where wm the electrode width or space; delta f Delta f/3N; Delta f the bandwidth; f1 the lowest band frequency; m 1,3,5...3N for the electrode widths; m 2,4,6...(3N-1) for the spaces between electrodes; and N total electrode pairs.

Claim 3

A surface wave preselector comprising: a. a piezoelectric base member; b. a first array of interdigital transmitter grids deposited on said base, each of said grids being connected to an input signal and having a plurality of parallel electrodes adapted to generate surface waves in said base of a selected frequency and bandwidth in response to an input signal having said frequencies; and c. a second array of interdigital receiver grids deposited on said base, the number of said receiver grids being greater than the number of transmitter grids, each of said receiver grids including a plurality of parallel electrodes adapted to receive a surface wave of selected frequency and bandwidth and produce an output signal, at least one of said receiver grids being adapted to receive a surface wave of a frequency associated with at least one of said transmitter grids and having a bandwidth less than said associated transmitter grid, said associated grids of said first and second arrays being opposingly positioned on said base, said electrodes of each of said transmitter and receiver grids having widths and spaces therebetween in accordance with the following general formula: wm v/4 (1/f1 + (m-1) delta f), where wm the electrode width or space; delta f Delta f/3N; Delta f the bandwidth; f1 the lowest band frequency; m 1,3,5...3N for the electrode widths; m 2,4,6...(3N-1) for the spaces between electrodes; and N total electrode pairS.

Claim 4

A surface wave preselector comprising: a. a piezoelectric base member; b. a first array of interdigital transmitter grids deposited on said base, each of said grids being connected to an input signal and having a plurality of parallel electrodes adapted to generate surface waves in said base of a selected frequency and bandwidth in response to an input signal having said frequencies; and c. a second array of interdigital receiver grids deposited on said base, the number of said receiver grids being greater than the number of transmitter grids, each of said receiver grids including a plurality of parallel electrodes adapted to receive a surface wave of selected frequency and bandwidth and produce an output signal, at least one of said receiver grids being adapted to receive a surface wave of a frequency associated with at least one of said transmitter grids and having a bandwidth less than said associated transmitter grid, said associated grids of said first and second arrays being opposingly positioned on said base, said electrodes of each of said transmitter and receiver grids having widths and spaces therebetween in accordance with the following general formula: wm v/4 (1/f1 + (m-1) delta f), where wm the electrode width or space; delta f Delta f/3N; Delta f the bandwidth; f1 the lowest band frequency; m 1,3,5...3N for the electrode widths; m 2,4,6...(3N-1) for the spaces between electrodes; and N total electrode pairS.

Claim 5

A surface wave preselector as set forth in claim 2 wherein said second array includes a first and second set of receiver grids, each of said first and second sets comprising the same number of receiver grids as transmitter grids, said receiver grids of said first and second sets being positioned on opposite sides of frequency associated transmitter grids.

Claim 6

A surface wave preselector as set forth in claim 3 wherein the center frequency of each of said transmitter grids is selected to be midway between the center frequencies of said associated receiver grids positioned on opposite sides thereof.