TX to Ae

Z_matching

Bridges

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Patents
US Patent documents are available free from United States Patent and Trademark Office. (You will need to install a TIFF viewer to view page images - see the USPTO images help page). US Patents are public domain documents and so, for convenience, some are reproduced here in an online readable form.
See also: www.google.com/patents (which allows keyword searching of OCR versions of old Patents).

Bridges, Directional Couplers, Indicators, Automatic Z Matching:
  US 1454011. Blackwell 1923. System for Attaining Uniform Attenuation.
US 2134589. Stanek 1938. Apparatus for Measuring High-Frequency Alternating Currents.
US 2157006. Oestinghaus 1939. Current and Voltage Responsive Apparatus.
US 2165848. Gothe, Buschbeck, Kautter 1939. Protection of High Frequency Lines.
US 2191271. Carter 1940. Means for making impedance measurements at high radio frequencies.
US 2214915. Wehrlin 1940. High Frequency Current Transformer.
US 2238298. Wehrlin 1941. High Frequency Current Measuring Device.
US 2278687. Brown 1942. Radio frequency wattmeter
US 2285211. Korman 1942. Radio frequency Wattmeter [Improvement to US 2278687, uses CVS with compensation resistor].
US 2297255. Schulze-Herringen, Gutzmann 1942. Phase Control in High Frequency Coupled Circuits.
US 2344641. Rosencrans 1944. Radio Frequency Wattmeter.
US 2362372. Halfmann 1944. Apparatus for Measuring Alternating Current in the Conductors and/or Sheaths of Electric Cables.
US 2365207 Moles 1944. High Frequency Thermocouple.
US 2412393. Ghosh 1946. Reflectometer correction network [Improvement to USP 2423416].
US 2415799. Reifel, Crandell 1947. Automatic Means for Controlling the Power fed to an Oscillator Load.
US 2423390. Korman 1947. Reflectometer for Transmission Lines and Wave Guides.
US 2423416. Sontheimer, Korman 1947. Non-Frequency-Selective Reflectometer.
US 2423526. Sontheimer, Korman 1947. Waveguide reflectometer.
US 2443097 Crosby 1948. Radio Frequency Wattmeter.
US 2467648. Alexander 1949. Transmission Line Energy Indicator.
US 2511026. Wadhams, Sateren, Sikorski 1950. Method for Controlling Heating by an Induction Heating Circuit.
US 2588390. Jones 1952. High-Frequency Power Measuring Device.
US 2611030. Sontheimer 1952. Energy Transfer System.

US 2734169. Douma 1956. Directional Apparatus for use with HF Transmission Lines [Extension of USP 2808566 to include correction for generator-side capacitance].
   Analysis of Douma's generator power-factor correction scheme (DWK).

US 2745067. True, Fisk 1956. Automatic Impedance Matching Apparatus.
US 2788396. Abraham 1957. Balancing Arrangement.
US 2797387. Adams, Horvath, Parzen 1957. Standing Wave Ratio Monitor.
US 2808566. Douma 1957. Directional Apparatus for use with HF Transmission Lines.
US 2834887. Brown 1958. Control Systems for Matching Impedance Networks.
US 3020529. Turner 1962. Reflected Power Alarm for a Variable Power Output Antenna System.
US 3048798. Simons 1962. Directional Coupler.
US 3145338. Downs 1964. Combination Transmission System Phase and Impedance Sensor Having a Single Centre-Tapped Probe.
US 3281721. Clark 1966. Impedance Matching System.
US 3369128. Pearlman 1968. Logarithmic Function Generator.
US 3426298. Sontheimer, Fredrick 1969. Broadband Directional Coupler.
US 3443231. Roza 1969. Impedance Matching System.
US 3683274. Martin 1972. Lumped Component SWR Indicators for RF Transmission Lines.
US 3704409. Oomen 1972. Digital Reflection Coefficient Detector.
US 3715690. Young, Radler 1973. Automatic Tuning Electric Wave Filter.
US 3716806. Zelenz 1973. Signal Coupling Apparatus Utilizing Hybrid Transformer,
US 3794941. Templin 1974. Automatic Antenna Impedance Tuner Including Digital Control Circuits.
US 3798574. Workman 1974. Directional Coupler Having Directly Connected Taps.
US 3835379. Templin 1974. Detector Circuits for Signal Transmission.
US 3919643. Templin 1975. Phase Sensor Circuit.
US 3919644. Smolka 1975. Automatic Antenna Coupler Utilizing System for Measuring the Real Part of the Complex Impedance or Admittance Presented by an Antenna or Other Network.
US 3995237. Brunner 1976. Automatic Matching Method and Apparatus.
US 4011529. Garcia 1977. Directional Power Detector for Propagating Waves.
US 4015223. Chezé 1977. HF Antenna Matching Device.
US 4028645. Tressa 1977. Automatic Impedance Matching Using Resistive and Reactive Diodes.
US 4041395. Hill 1977. Transmitter Performance Monitor and Antenna Matching System.
US 4075554. Mecklenberg 1978. VSWR Meter Circuit Using Variable RF Attenuator.
US 4110685. Leenerts 1978. Standing Wave Ratio Measurement Instrument.
US 4156842. Huang, Brooks 1979. Immitance [i.e., Impedance / Admittance] Measurement with High-Frequency Injection and Electromagnetic Coupling.
US 4234960. Spilsbury, Spilsbury 1980. Antenna Automatic Tuning Apparatus.
US 4283794. Underhill, Lewis 1981. Measuring Radio-Frequency Impedance.
US 4285346. Armitage 1981. Electrode System.
US 4356458. Armitage 1982. Automatic Impedance Matching Apparatus.
US 4463308. Underhill 1984. R.F. Impedance Determination.
US 4493112. Bruene 1985. Antenna Tuner Discriminator.

US 4739515. Herzog 1988. VSWR Bridge Measuring Circuit.
    Analysis of Herzog's current-transformer LF-compensation method (DWK)
   + Spreadsheet Herzog_LF.ods .

US 5150063. Burkhard 1992. Bridge for Measuring the Reflection Coefficient.


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