RF-EXCITED TRANSDUCER

• US 3,634,756 A
• Filed: 03/09/1970
• Issued: 01/11/1972
• Est. Priority Date: 03/09/1970
• Status: Expired due to Term

• Current Assignee: Robert L. Carlise
• Original Assignee: Robert L. Carlise
• Inventors: Carlise, Robert L.
• Primary Examiner(s): Smith, Alfred E.
• Application Number:
  US05/017,547
• Time in Patent Office: 673 Days
• Field of Search: 324/58.5A,84,58.5B
• US Class Current: 324/644
• CPC Class Codes: G01B 15/00 Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons characterised by the use of optical techniques G01B9/00, G01B11/00
• CPC Class Codes: G01N 22/00 Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more G01N3/00 - G01N17/00, G01N24/00 take precedence

Abstract

RF carrier wave excited transducer means for providing a bipolar output signal having a sense and magnitude indicative of the sense and magnitude of a detected change of state from a reference state and corresponding to a fractional wavelength of the carrier wave. Modulating means responsive to a detected state modulates an applied carrier wave excitation as a function of the detected state. Hybrid junction means responsive to the applied carrier and to the modulated carrier provides two RF outputs in mutual time phase quadrature. Detected signal summing means having oppositely poled first and second detected inputs, each responsive to a respective one of said hybrid junction outputs, provides a bipolar output indicative of the difference between said hybrid outputs.

Claims

1. An RF carrier excitable position transducer comprising a first sidewall hybrid having a first port connected by an RF isolator to a source of a fixed frequency RF carrier wave, a second port connected in circuit with an RF radiating aperture, and further having a third and fourth port;

a second sidewall hybrid having a first and second input port responsively coupled to a respective one of said third and fourth ports of said first sidewall hybrid, and further having a third summing output port and a fourth difference output port quadrature time phase shifted relative to said third summing output port;

oppositely poled first and second detector means responsive to a respective onE of said third summing and fourth difference output ports of said second sidewall hybrid for providing a respective first and second detected signal of mutually opposite polarity; and

output signal summing means responsive to said first and second detected signals for providing an output signal indicative of the algebraic sum of said detected signals;

calibration means for calibrating said transducer relative to a selected reference position of interest, and comprising said output signal summing means, said signal summing means being a potentiometer having an output wiper and further having a two-terminal resistive element, each of the two terminals of which are connected in circuit to a respective one of said oppositely poled detector means, a normally closed switch interposed in series circuit between one of said terminals and an associated detector means, a slide screw tuner interposed in series circuit between said first and second sidewall hybrids by means of a circulator having at least three ports for adjusting the relative time phase between the two inputs of said second sidewall hybrid, said output signal summing means including means for adjusting the relative attenuation between the two detected signals applied thereto.