Patents by Inventor Hilmer I. Swanson

Hilmer I. Swanson 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: 5309114
    Abstract: A pulse step modulator (PSM) is disclosed herein and having particular use in AM radio broadcasting. This modulator includes a plurality of series connected unit step voltage modules each including a DC voltage source and an associated actuatable switch for, when actuated, turning on the associated module to provide a unit step voltage of a given magnitude. An output circuit is connected to the modules for providing an output voltage to a load wherein the magnitude of the output voltage is a multiple of a unit step voltage in dependence upon the number of modules that are turned on. Each module exhibits the characteristic of dissipating heat when the module is turned on with the amount of heat dissipated being a function of the time duration that the module is turned on.
    Type: Grant
    Filed: June 30, 1993
    Date of Patent: May 3, 1994
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 5216376
    Abstract: An amplifier system is disclosed having distortion reduction. The system includes a pulse duration modulator having an input circuit for receiving an input signal, such as an audio signal, for providing a train of pulses exhibiting a fixed repetition rate and a fixed amplitude and having varying widths dependent upon the magnitude of the input signal. A switch is provided having an input circuit for receiving the PDM pulses and responds thereto so as to be on for a duration dependent upon the pulse width. The switch has an output circuit connected in series with a load across a DC voltage source to provide an amplified output signal to the load. A signal detector is connected to the output circuit to provide a correction signal having a value that various proportional to that of the amplified output signal. The input signal is divided by the correction signal prior to application to the input circuit of the pulse duration modulator.
    Type: Grant
    Filed: June 10, 1992
    Date of Patent: June 1, 1993
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 5132637
    Abstract: An RF power amplifier system is provided having improved distortion reduction. This system includes a plurality of actuatable RF power amplifiers, each connected to a DC voltage source and each having an input circuit for when actuated receiving and amplifying an RF drive signal and each having an output circuit for providing an amplified RF output signal. One or more of these RF power amplifiers are actuated, turned on, in dependence upon the magnitude of an input audio frequency signal. The RF output signals are additively combined to provide a combined RF output signal. RF output signal detector means are connected to the output circuit of at least one of the RF power amplifiers for providing a correction signal having a value which varies as a function of the value of the RF voltage detected at the output circuit. The correction signal is combined with the input signal prior to actuation of one or more of the RF power amplifiers.
    Type: Grant
    Filed: March 25, 1991
    Date of Patent: July 21, 1992
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 5111158
    Abstract: An RF power amplifier system is disclosed having a modulated voltage supply and fault monitoring thereof. The modulated DC voltage supply receives an input voltage as well as a modulating signal, such as an audio signal, to provide a modulated voltage which has been amplitude modulated in accordance with the amplitude variations of the modulating signal. Circuitry is provided for providing a variable reference signal which has a magnitude that varies with that of the modulating signal. A fault comparator compares the modulated signal with the variable reference signal and provides a fault signal dependent upon the comparison.
    Type: Grant
    Filed: June 27, 1991
    Date of Patent: May 5, 1992
    Assignee: Harris Corporation
    Inventors: Jeffrey M. Malec, Hilmer I. Swanson
  • Patent number: 5070309
    Abstract: An RF power amplifier having amplifier protection is presented wherein an RF source supplies an RF input signal to an actuatable RF power amplifier having an on condition and an off condition for, when on, normally receiving and amplifying the input RF signal to provide an amplified output RF signal. RF current and RF voltage in the output circuit are detected. A first signal is provided from the RF current and exhibits a fixed amplitude but a frequency and phase corresponding with that of the RF current. A second signal is provided of the fixed amplitude and which corresponds in frequency and phase with the RF voltage. The first and second signals are compared so as to provide a phase signal having a magnitude dependent upon the phase difference between the first and second signals. This phase signal is then compared with a reference to provide a turn-off signal in dependence upon the comparison for purposes of actuating an RF power amplifier to its off condition.
    Type: Grant
    Filed: January 28, 1991
    Date of Patent: December 3, 1991
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 5003271
    Abstract: The amplifier includes a bridge circuit having an input circuit adapted for connection across a DC voltage source and an output circuit connected across a load. The bridge circuit includes first and second transistors for, when on, connecting the DC voltage source across the load for DC current flow therethrough in a first direction and third and fourth transistors for, when on, connecting the DC voltage source across the load for DC current flow therethrough in a second direction. The transistors are controlled by an RF signal so that they turn on and off at a frequency dependent upon that of the RF signal such that current flows from the DC source alternately in the first and second directions through the load.
    Type: Grant
    Filed: March 5, 1990
    Date of Patent: March 26, 1991
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 4952890
    Abstract: An RF amplitude modulated amplifier system is presented incorporating a plurality of RF amplifiers which are compensated for unwanted phase modulation. The system includes a common RF driver for supplying a common RF driver signal. A plurality of actuatable RF amplifiers are provided with each having an input circuit for receiving the common RF drive signal. Each amplifier has a fully on condition for amplifying the common drive signal to provide an amplified RF signal, and a fully off condition. Each of these RF amplifiers exhibits a characteristic in that its input circuit has an input impedance which is greater when fully on than that when fully off, thereby tending to present unwanted phase modulation of the plurality of RF amplifiers. One or more of the RF amplifiers are selectively turned fully on in dependence upon the magnitude of an input signal.
    Type: Grant
    Filed: September 12, 1989
    Date of Patent: August 28, 1990
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 4949050
    Abstract: An RF power amplifier having improved amplifier protection. An RF source provides an RF signal to be amplified. The amplifier includes a bridge circuit having an input circuit adapted for connection across a DC voltage source and an output circuit connected across a load. The bridge circuit includes first and second transistors for, when on, connecting the DC voltage source across the load for DC current flow therethrough in a first direction and third and fourth transistors for, when on, connecting the DC voltage source across the load for DC current flow therethrough in a second direction. The transistors are controlled in response to the RF signal so that they turn on and off at a frequency dependent upon that of the RF signal and such that current flows from the DC source alternately in the first and second directions through the load. An amplifier control serves to apply a reverse bias to the second and fourth transistors to prevent them from conducting current until receipt of a turn on signal.
    Type: Grant
    Filed: September 12, 1989
    Date of Patent: August 14, 1990
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 4947455
    Abstract: An RF power supply serves to supply a regulated power amplified RF drive signal to an RF transmitter. The supply includes an RF oscillator for providing an RF input signal. A DC voltage source provides a DC voltage V. A plurality of power amplifiers are provided with each receiving the input RF signal and each having an input for receiving a DC voltage signal, and each serving to amplify the input RF signal by an amount dependent upon the magnitude of the DC voltage signal supplied to its input and thereby provide an amplified RF signal. The amplified RF signals are combined to provide an RF drive signal. The DC voltage V is directly supplied to the input of at least a first one of the power amplifiers.
    Type: Grant
    Filed: November 9, 1988
    Date of Patent: August 7, 1990
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 4859967
    Abstract: An RF power amplifier is operated by supplying an RF signal to the amplifier for amplification and thereby providing an output RF signal to the amplifier's output circuit which has an impedance matching output network connected in series with a load. A detector serves to detect any reflected power in the output circuit. The RF power amplifier is turned off when the detected RF power exceeds a reference level. The amplifier is protected by discontinuing the supply of the RF signal to the amplifier while it is turned off and, instead, a frequency signal is supplied to the RF amplifier having a frequency that corresponds with that of any current flowing in the output circuit.
    Type: Grant
    Filed: November 9, 1988
    Date of Patent: August 22, 1989
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 4737731
    Abstract: Amplitude modulation apparatus is provided having means for providing a radio frequency carrier signal, and means for receiving an audio frequency signal to be used to amplitude modulate the RF carrier signal. Amplitude modulator means is provided responsive to the AF signal and to the RF carrier signal for amplitude modulating the RF carrier signal in accordance with the AF signal so as to thereby provide an amplitude modulated RF carrier signal. A power supply provides at least one DC power signal for powering the amplitude modulator means. Correction means is included for sensing variations in the DC power signal and for gain adjusting the audio frequency signal in accordance with the variations in the DC power signal, whereby modulation distortion of the amplitude modulated RF carrier signal is reduced.
    Type: Grant
    Filed: October 24, 1986
    Date of Patent: April 12, 1988
    Assignee: Harris Corporation
    Inventors: Hilmer I. Swanson, Scott A. McFarland
  • Patent number: 4680559
    Abstract: A signal dividing network is provided as an RF splitter for use in supplying N load devices of varying impedances with RF signals such that each of the N signals is of essentially the same magnitude and phase. The splitter includes a plurality of step-down auto transformers, each having a primary and a secondary defining a series circuit between a common RF source and ground. An output terminal is defined as the midpoint of the primary and secondary windings on each transformer and the output terminals are connected together in common whereby all of the primary windings are connected in parallel and all of the secondary windings are in parallel. Each output terminal has several outputs connected thereto such that the splitter has a total of N outputs for driving N load devices.
    Type: Grant
    Filed: March 14, 1985
    Date of Patent: July 14, 1987
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 4580111
    Abstract: An amplitude modulator (10) is disclosed which generates an amplitude modulated carrier signal by selectively combining varying numbers of other carrier signals. A circuit (20) is included which provides plural carrier signals of like frequency and phase where the number of carrier signals being provided is dependent upon the level of an input signal. A combiner circuit (22) combines the plural carrier signals to thereby provide a combined signal which is the desired amplitude modulated carrier signal. In one embodiment (FIG. 3) the carrier signals which are combined are all equal in amplitude. In another embodiment (FIG. 4) the amplitudes of some of the carrier signals are weighted in a binary progression. In yet another embodiment (FIG. 9) the carrier signals are all frequency modulated whereby the output signal has both a varying frequency and amplitude.
    Type: Grant
    Filed: December 24, 1981
    Date of Patent: April 1, 1986
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 4510456
    Abstract: A pulse duration modulator (PDM) provides a train of pulses at a fixed repetition rate and a fixed amplitude but of a pulse width dependent upon an input signal. A switching transistor receives this pulse and is turned on for a duration dependent on the pulse width. The output circuit of the transistor is connected to a load for receiving an amplified version of the pulse train. Stray capacitance across the output circuit causes distortion in the amplified pulse particularly when the switch on time is less than the off time. A distortion reduction circuit is connected to the output circuit for inserting or increasing the current flowing to the output circuit to more rapidly charge the stray capacitance and thereby reduce distortion.
    Type: Grant
    Filed: September 28, 1983
    Date of Patent: April 9, 1985
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 4468626
    Abstract: A polyphase PDM amplifier is disclosed including plural parallel PDM amplifier stages (10, 12, 14, 16), all amplifying the same input signal. The PDM amplifier outputs are combined to produce a combined amplifier output. The various PDM amplifier stages modulate PDM carrier signals of like frequencies but differing phases. Capacitors (40, 42, 44, 46) are connected from each amplifier output to a common circuit node (48). These capacitors reduce the amplitudes of the spurious, out-of-phase components in the amplifier outputs which are introduced by the PDM modulation-demodulation process.
    Type: Grant
    Filed: January 25, 1982
    Date of Patent: August 28, 1984
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 4403197
    Abstract: An amplifier (FIGS. 1-3) is disclosed for amplifying an amplitude and frequency varying input signal. The amplifier includes a circuit (24, 100) responsive to the input signal to provide a digital representation thereof. In addition, a plurality of signal sources (30-36) are provided which each provide an associated signal. Another circuit (38-52) combines selected ones of the associated signals in accordance with the digital representation to provide a first combined signal having substantially the same waveform as, but of greater amplitude than the input signal.In several embodiments, a circuit (74, 76-78) provides an error signal in accordance with the difference between the desired and actual forms of the first signal. This error signal is combined with the first combined signal to derive an error corrected signal.
    Type: Grant
    Filed: October 26, 1981
    Date of Patent: September 6, 1983
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson
  • Patent number: 4164714
    Abstract: A system wherein input signals are pulse duration modulated to provide a plurality of pulse trains having a predetermined phase relation therebetween. The plurality of pulse trains control the operation of separate switching elements. The output of the switching elements are summed and filtered to provide a composite amplified signal. The number of switching elements and the number of pulse trains are determined by the desired fidelity of operation and the frequency response of the switching elements. The system is particularly useful as a power audio amplifier for use in modulating stages of RF transmitters.
    Type: Grant
    Filed: September 26, 1977
    Date of Patent: August 14, 1979
    Assignee: Harris Corporation
    Inventor: Hilmer I. Swanson