Average Carrier Amplitude Controlled By Modulating Signal Patents (Class 332/157)
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Patent number: 7933320Abstract: A communication system using a length shift keying (LSK) modulation method provides a transmitter having a carrier signal generator for generating carrier signals, and a modulator for modulating lengths of the carrier signals from the carrier signal generator according to combinations of data bits, and a receiver having an integrator for calculating an energy value by integrating the carrier signal that corresponds to a data bit combination, and a data judgment unit for judging the data bit combination by comparing the energy value with a predetermined threshold value. Power is maintained without changing the bandwidth of a communication signal when the communication signal is modulated.Type: GrantFiled: August 7, 2006Date of Patent: April 26, 2011Assignee: Samsung Electronics Co., Ltd.Inventors: Jae-hyon Kim, Young-hwan Kim, Seong-soo Lee
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Patent number: 7382208Abstract: The operating method is based on the simultaneous application of FM and AM. In this process, the fundamental frequency of the AM is derived from at least one, preferably the second, longitudinal mode. In continuous operation of the lamp, the color temperature is set for a prescribed power by setting the AM degree controllably.Type: GrantFiled: January 25, 2005Date of Patent: June 3, 2008Assignee: Patent-Treuhand-Gesellschaft für Elektrische Glühlampen MbHInventor: Klaus Stockwald
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Patent number: 6937108Abstract: A method and apparatus for producing a modulation scheme usable in conjunction with information transmission and reception via waveforms, such as electromagnetic waves. The modulation scheme is usable for such purposes as resolving range ambiguities and overcoming fading and interference problems via use of offset signals that vary in frequency over time (e.g., chirp signals), which spread the signal over a larger bandwidth. The method includes coding a symbol signal onto a split data stream containing a reference signal (e.g., a chirp), to which a time delay has been applied, then recombining the split streams to produce a composite waveform. The method can also include demodulating a composite received waveform by applying a reference signal to the waveform and then band pass filtering the waveform into discrete symbol data. Apparatus and systems are also provided for performing the method.Type: GrantFiled: March 11, 2003Date of Patent: August 30, 2005Assignee: M/A-Com, Inc.Inventor: Alan Jenkins
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Patent number: 5896182Abstract: Amplitude modulator comprising a differential input pair receiving a modulating input signal, and a Gilbert cell multiplying a carrier signal by the modulating input signal; anda second differential pair of transistors receiving the carrier signal, and the output signal of which is added to the output signal of the Gilbert cell.Type: GrantFiled: June 11, 1996Date of Patent: April 20, 1999Assignee: U.S. Philips CorporationInventor: Philippe Klaeyle
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Patent number: 5661442Abstract: An amplitude control system uses a pair of parallel integrators to rapidly adjust the amplitude of a test signal between two precisely determined power levels in an RF signal generator. The amplitude control system initializes a first power level by switching a first integrator into a feedback signal path to establish a first drive voltage, corresponding to the first power level. A second power level is initialized by switching a second integrator into the feedback signal path to establish a second drive voltage, corresponding to the second power level. The amplitude control system then alternately switches each of the integrators into the feedback signal path to alternately apply the first and second drive voltages to a level modulator, which rapidly adjusts the amplitude of the test signal to each of the two initialized power levels.Type: GrantFiled: July 2, 1996Date of Patent: August 26, 1997Assignee: Hewlett-Packard CompanyInventor: Stephen T. Sparks
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Patent number: 5054116Abstract: In a feedback loop level control circuit for an RF source, the RF output is sensed and compared to a reference level which determines the desired output power level. The difference between the output sample and the reference level constitutes an error signal which is applied to an integrator. The reference level is summed with the output of the integrator and the resulting sum is used to control a modulator which variably attenuates the RF output. When the system is operating in a pulse amplitude modulation mode, the reference level signal is modulated and compared to a threshold signal that determines the lowest output level that can be accurately sensed. If the modulated reference level is above the threshold, the feedback loop is closed, otherwise when the modulation signal reduces the output power level to a level which is too low to detect accurately, the feedback loop is opened.Type: GrantFiled: September 29, 1989Date of Patent: October 1, 1991Assignee: Hewlett-Packard CompanyInventor: Mark N. Davidson
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Patent number: 4864635Abstract: In an AM broadcast transmitter having a switching amplifier as main modulator (12), an additional modulator (18) is used in the radio frequency circuit in order to achieve a steady 100% modulation at the modulation minima, with the aid of which additional modulator the carrier signal is also modulated at the modulation minima. The LF signal needed for controlling the additional modulator (18) passes through a delay circuit (16) and a correction circuit (17).Type: GrantFiled: November 12, 1987Date of Patent: September 5, 1989Assignee: BBC Brown Boveri AGInventors: Bohumil Kyrian, Wilhelm Tschol