Method and device for providing a variable delay line

Claim 1

A device for varying the delay of a delay line comprising an elongated bar (F) of ferroelectric material of substantially uniform cross-section and having a wall (P) where the piezoelectric constant is discontinuously disposed in the path of a wave propagated longitudinally in said bar and further comprising means for producing and regulating the position of a wall (P) where the piezoelectric constant is discontinuous, the wall coinciding with the position of a flat equipotential surface oriented transversely of the bar, the device being characterised in that said elongated bar made of a ferroelectric material is provided with first and second polarizing electrodes on opposite sides of the bar with respect to a polarity direction transverse of said bar, said electrodes respectively being a first electrode (S1) made of a conductive material and a second electrode (S2) made of resistive material, and in that a d.c. voltage (Vc) is applied to said first electrode (S1) and d.c. voltages +Vp and Vp are applied to the two longitudinally spaced ends (P1 and P2) of said second electrode (S2) so that -Vp < Vc < Vp.

Claim 2

A device for varying the delay of a delay line comprising an elongated bar (F) of ferroelectric material of substantially uniform cross-section and having a wall (P) where the piezoelectric constant is discontinuously disposed in the path of a wave propagated longitudinally in said bar and further comprising means for producing and regulating the position of a wall (P) where the piezoelectric constant is discontinuous, the wall coinciding with the position of a flat equipotential surface oriented transversely of the bar, the device being characterised in that said elongated bar made of a ferroelectric material is provided with first and second polarizing electrodes on opposite sides of the bar with respect to a polarity direction transverse of said bar, said electrodes respectively being a first electrode (S1) made of a conductive material and a second electrode (S2) made of resistive material, and in that a d.c. voltage (Vc) is applied to said first electrode (S1) and d.c. voltages +Vp and Vp are applied to the two longitudinally spaced ends (P1 and P2) of said second electrode (S2) so that -Vp < Vc < Vp.

Claim 7

A device for providing a delay line of variable delay comprising an elongated bar (F) of ferromagnetic material of substantially uniform cross-section having an axis of easy magnetization (0z'') perpendicular to the direction of elongation of said bar and further comprising first and second magnetizing coils (B''1 and B''2) arranged to be energized by adjustable currents producing opposite magnetic fields in opposite directions of said axis of easy magnetization respectively in two portions of said bar on opposite sides of a magnetic domain wall transversely intersecting said bar, whereby the adjustment of the respective magnitudes of said currentsf determines the location of said magnetic domain wall along the longitudinal direction of said bar, and further comprising means at one end of said bar for magnetostrictively exciting modulated acoustic waves in said bar and means for detecting the passage of said acoustic waves through said domain wall.

Claim 8

A device for providing a delay line of variable delay comprising an elongated bar (F) of ferromagnetic material of substantially uniform cross-section having an axis of easy magnetization (0z'') perpendicular to the direction of elongation of said bar and further comprising first and second magnetizing coils (B''1 and B''2) arranged to be energized by adjustable currents producing opposite magnetic fields in opposite directions of said axis of easy magnetization respectively in two portions of said bar on opposite sides of a magnetic domain wall transversely intersecting said bar, whereby the adjustment of the respective magnitudes of said currentsf determines the location of said magnetic domain wall along the longitudinal direction of said bar, and further comprising means at one end of said bar for magnetostrictively exciting modulated acoustic waves in said bar and means for detecting the passage of said acoustic waves through said domain wall.

Claim 11

A method of providing a variable delay of an electric signal comprising the steps of: maintaining two adjacent regions of oppositely directed electric fields in an elongated bar of ferroelectric material having substantially uniform cross-section, the boundary between said regions being transverse to the longitudinal directions of said bar, said oppositely directed electric fields being maintained by the application of d.c. voltages to electrodes respectively extending along a substantial length of said bar on opposite sides of said bar with respect to a direction of electric field polarization, said application of potentials including applications of different potentials to the ends of a first of said electrodes constituted of resistive materiAl and the application of an adjustable potential intermediate between said different potentials to the second of said electrodes, said second electrodes being made of conductive materials, thereby defining the location of an equid potential surface transverse to said bar constituting a wall between oppositely polarized regions of said bar; exciting at one end of said bar modulated acoustic waves that propagate along the length of said bar, said acoustic waves being modulated by a signal to be delayed and being excited piezoelectrically, and detecting the passage of said modulated acoustic waves through said wall between said oppositely polarized regions in said bar, by detecting potentials piezoelectrically excited in an additional electrode extending substantially over said length of said bar opposite the aforesaid conductive electrode.

Claim 12

A method of providing a variable delay of an electric signal comprising the steps of: maintaining two adjacent regions of oppositely directed electric fields in an elongated bar of ferroelectric material having substantially uniform cross-section, the boundary between said regions being transverse to the longitudinal directions of said bar, said oppositely directed electric fields being maintained by the application of d.c. voltages to electrodes respectively extending along a substantial length of said bar on opposite sides of said bar with respect to a direction of electric field polarization, said application of potentials including applications of different potentials to the ends of a first of said electrodes constituted of resistive materiAl and the application of an adjustable potential intermediate between said different potentials to the second of said electrodes, said second electrodes being made of conductive materials, thereby defining the location of an equid potential surface transverse to said bar constituting a wall between oppositely polarized regions of said bar; exciting at one end of said bar modulated acoustic waves that propagate along the length of said bar, said acoustic waves being modulated by a signal to be delayed and being excited piezoelectrically, and detecting the passage of said modulated acoustic waves through said wall between said oppositely polarized regions in said bar, by detecting potentials piezoelectrically excited in an additional electrode extending substantially over said length of said bar opposite the aforesaid conductive electrode.

Claim 14

A method of providing a variable delay of an electric signal which comprises the steps of: maintaining regions of oppositely directed magnetic fields in an elongated ferromagnetic bar of substantially uniform cross-section, said oppositely directed magnetic fields being directed parallel to an axis of easy magnetization which is perpendicular to the direction of elongation of said bar, said regions being thereby separated by a domain wall transverse to said bar, the step of maintaining said regions of oppositely directed magnetization being performed by maintaining magnetizing currents respectively in a plurality of coils arranged to magnetize respectively in one direction and the opposite direction parallel to said transverse axis of magnetization of said bar; magnetostrictively exciting one end of said bar to propagate a longitudinal modulated acoustic carrier wave towards the other end of the bar, the modulation of the carrier frequency of said wave being in accordance with the signal to be delayed, and detecting the passage of said modulated acoustic wave through said domain wall in said bar.

Claim 15

A method of providing a variable delay of an electric signal which comprises the steps of: maintaining regions of oppositely directed magnetic fields in an elongated ferromagnetic bar of substantially uniform cross-section, said oppositely directed magnetic fields being directed parallel to an axis of easy magnetization which is perpendicular to the direction of elongation of said bar, said regions being thereby separated by a domain wall transverse to said bar, the step of maintaining said regions of oppositely directed magnetization being performed by maintaining magnetizing currents respectively in a plurality of coils arranged to magnetize respectively in one direction and the opposite direction parallel to said transverse axis of magnetization of said bar; magnetostrictively exciting one end of said bar to propagate a longitudinal modulated acoustic carrier wave towards the other end of the bar, the modulation of the carrier frequency of said wave being in accordance with the signal to be delayed, and detecting the passage of said modulated acoustic wave through said domain wall in said bar.