Patents by Inventor Thomas H. Donahue

Thomas H. Donahue has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4259650
    Abstract: Disclosed is a Sidelobe Rejection Filter for reducing the time sidelobes seen in the auto-correlation output signals from a matched filter. Such matched filters are used with radars utilizing pulse compression techniques, for example. The sidelobe rejection filter may be utilized whenever the time response of the auto-correlation signals includes a plurality of sidelobes each having a period .tau. and having essentially the same amplitude. Accordingly, the disclosed sidelobe rejection filter is particularly useful for pulse compression radars employing linear FM (i.e., Chirp) or Barker phase coded waveforms.The matched filter includes a delay circuit coupled to receive the time response of the auto-correlation signal, which delay circuit inserts a delay of .tau.
    Type: Grant
    Filed: March 19, 1979
    Date of Patent: March 31, 1981
    Assignee: International Telephone and Telegraph Corporation
    Inventor: Thomas H. Donahue
  • Patent number: 4104633
    Abstract: A constant false alarm rate video processor which uses a tapped delay line operating as a "sliding range window" to provide tap outputs corresponding to the center of the delay line and a predetermined number of discrete range cells on either side thereof. A "least of" circuit is responsive to all taps except the center tap of the delay line and the mininum signal extant on these taps is outputted and substracted (in scale factored form) from the signal of the delay line. The circuit thereby adaptively excludes target and ground clutter bias in providing the CFAR (normalized) signal output of the combination. An additional circuit arrangement is shown for digitally mapping the "least of" signal values over a predetermined threshold. The digital map output converted to analog then provides the scaled "least of" signal to be subtracted from the central range cell and for controlling the threshold of response of the mapper.
    Type: Grant
    Filed: April 18, 1977
    Date of Patent: August 1, 1978
    Assignee: International Telephone and Telegraph Corporation
    Inventors: Thomas H. Donahue, John F. Chaney
  • Patent number: 4089001
    Abstract: A coherence reference signal device, and utilizing radar system therefor, in which a coherent reference signal is provided for phase detection of target echo signals for subsequent application to a canceller or other signal processor. The device recognizes the phase conditions throughout a given transmitted pulse (range bin) and provides this same phase information repetitively for each of n range bins of interest. A tapped sonic delay line of metallic glass material with input and output transducers and a summer circuit provide the coherent reference signal produced to a phase detector which also receives the echo signals, preferably both in the IF frequency domain.
    Type: Grant
    Filed: May 6, 1977
    Date of Patent: May 9, 1978
    Assignee: International Telephone and Telegraph Corporation
    Inventor: Thomas H. Donahue
  • Patent number: 4040055
    Abstract: A digital compensator for radar transmitter instabilities for use in a digital MTI system. The I and Q coherent phase detector outputs are continuously monitored for phase, amplitude and timing instabilities and arithmetic correction signals are generated and applied to the digitized received signal values to compensate for these instabilities which are particularly characteristic of pulsed magnetron transmitters, for example.
    Type: Grant
    Filed: July 15, 1974
    Date of Patent: August 2, 1977
    Assignee: International Telephone and Telegraph Corporation
    Inventors: Thomas H. Donahue, David E. Hammers
  • Patent number: 3979697
    Abstract: An oscillator in which the "tank circuit" or feedback element is a surface acoustic wave (SAW) bandpass filter (delay line). A modulating voltage is applied from end-to-end of the piezoelectric substrate material to provide an incremental change of physical length of the substrate as a function of the modulating voltage. Two sets of interleaved fingers along a surface face of the substrate provide an interdigital arrangement for launching (electrical to acoustic transition) and receiving (acoustic to electrical transition) the surface acoustic wave.
    Type: Grant
    Filed: November 3, 1975
    Date of Patent: September 7, 1976
    Assignee: International Telephone and Telegraph Corporation
    Inventor: Thomas H. Donahue
  • Patent number: 3949398
    Abstract: An instantaneous gain controlling system particularly for coherent (MTI) radar systems. A gain controllable intermediate frequency amplifier, a COHO, and a phase detector are shown along with an MTI canceller which itself includes a delay device and a differencer are shown. The delay device provides a full pulse repetition period of delay, and the differencer operates to subtract the coherent video at the phase detector output from the same signal train, one pulse repetition interval earlier, to provide MTI cancellation. The delayed video train is full wave rectified, passed through a threshold circuit and an adjustable gain video amplifier and used as a pulse-by-pulse gain controlling signal for the intermediate frequency amplifier. Large signal blocks are thus prevented from overloading the receiver channel with consequent spectral spreading and MTI cancellation degradation.
    Type: Grant
    Filed: December 16, 1974
    Date of Patent: April 6, 1976
    Assignee: International Telephone and Telegraph Corporation
    Inventor: Thomas H. Donahue