Convertible To Different Type (e.g., Am To Fm) Patents (Class 455/93)
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Patent number: 5584051Abstract: The present invention provides for an analog and/or digital radio broadcast transmission system and radio receiver therefor, which includes a control signal having an item of control information concerning another, different type of transmission/receive system. The receiver is a hybrid receiver able to receive both types of signals. When the same program material is available on both of the different systems, the control signal is used for switching the different systems so that the receiver receives the program on the system which provides the best reception.Type: GrantFiled: July 25, 1994Date of Patent: December 10, 1996Assignee: Thomson Consumer Electronics Sales GmbHInventor: Klaus Goken
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Patent number: 5546051Abstract: In a dual-mode radio telephone transmitter operative in both an analog modulation mode based on the FDMA system and a digital modulation mode based on the TDMA system, a DC bias voltage Vdd to be applied to a power amplification circuit is varied in accordance with the type of modulation, so that the input/output characteristics of the power amplification circuit can be optimized. To this end, a micro processor controls a switch interposed between the power amplification circuit and a positive DC power unit in such a manner that the DC bias voltage Vdd is 4.8 V for the FDMA mode, while the DC bias voltage Vdd is 6.0 V for the TDMA mode. The value of another DC bias voltage Vgg in the power amplification circuit is fixed. The value of the DC bias voltage Vdd is set higher in the TDMA mode than in the FDMA mode; thus, it becomes possible to increase the power added efficiency in the FDMA mode, without adversely affecting high linearity and high efficiency in the TDMA mode.Type: GrantFiled: March 10, 1995Date of Patent: August 13, 1996Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Haruhiko Koizumi, Akihisa Sugimura, Kazuki Tateoka, Kunihiko Kanazawa
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Patent number: 5541554Abstract: An amplifier (100) has first and second operation modes. The amplifier (100) includes an amplifier input portion (110) and an amplification gain stage. The amplification stage has two gain paths (120, 140) coupled in parallel to the amplifier input portion (110). At least one of the gain paths (120) has an amplification component (121) that in part forms a switch to select between the first and second operation modes.Type: GrantFiled: March 6, 1995Date of Patent: July 30, 1996Assignee: Motorola, Inc.Inventors: Robert E. Stengel, Scott A. Olson
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Patent number: 5539770Abstract: A spread spectrum modulating apparatus includes an oscillator outputting a carrier. A frequency multiplier multiplies a frequency of the carrier by a predetermined integer N1. A frequency divider divides the frequency of the carrier by a predetermined integer N2. A spread code generator uses an output signal of the frequency divider as a clock signal, and generates a spread code in response to the clock signal. A power supply feeds a dc bias voltage. An operation device executes a predetermined logic operation between the spread code and the dc bias voltage of the power supply. A switch selectively feeds an input information signal to either the oscillator or the point of connection of the power supply to the operation device, selecting between PSK and FSK as primary modulation. An output signal of the operation device and an output signal of the frequency multiplier are multiplied to execute a spectrum spreading process.Type: GrantFiled: November 15, 1994Date of Patent: July 23, 1996Assignee: Victor Company of Japan, Ltd.Inventor: Yukinobu Ishigaki
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Patent number: 5530923Abstract: A dual mode transmitter circuit is disclosed including a non-linear high-power amplifier having an amplification that can be adjusted and a linear high-power amplifier. A first switch and a second switch are connected to the input and output of the linear, high-power amplifier. An amplification-adjustable, high-frequency transmitter control amplifier is connected to the input of the non-linear high-power amplifier. Apparatus for measuring transmission power such as a directional coupler is connected to the second switch, and a duplex filter is connected to the directional coupler. A power level control circuit is responsive to the measured transmission power from the directional coupler and to a power level signal. The power level signal is representative of the desired output power of the transmitter.Type: GrantFiled: March 30, 1994Date of Patent: June 25, 1996Assignee: Nokia Mobile Phones Ltd.Inventors: Jarmo Heinonen, Jaakko Hulkko, Toivo Vilmi
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Patent number: 5521559Abstract: A coefficient circuit 11 multiplies a digitized input modulation signal by a constant and outputs the multiplied signal. Delay circuits 12 and 13 delay the discrete in-phase input signal and discrete quadrature-phase input signal by 1 sampling cycle, respectively. A multiplying circuit 14 multiplies the multiplied signal by the 1-sampling cycle delayed discrete quadrature-phase input signal. The multiplying circuit 15 multiplies the multiplied signal by the 1-sampling cycle delayed discrete in-phase input signal. The adder circuit 16 adds the multiplication results of the multiplying circuit 14 to the 1-sampling cycle delayed discrete in-phase input signal and outputs the addition result as the discrete in-phase input signal. The subtracting circuit 17 subtracts the multiplication results of the multiplying circuit 15 from the 1-sampling cycle delayed discrete quadrature-phase input signal and outputs the subtraction result as the discrete quadrature-phase input signal.Type: GrantFiled: July 11, 1995Date of Patent: May 28, 1996Assignee: NEC CorporationInventor: Masaki Ichihara
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Patent number: 5507033Abstract: A system and method for reducing amplitude distortion in a data signal transmitted through a cellular analog communication system is embodied in several forms. Each specific embodiment of the invention eliminates distortion caused by clipping or sluggish recovery time induced by a limiter circuit which exists in conventional cellular communication systems. In one embodiment, pre-emphasis and de-emphasis functions of the cellular system are offset by complementary de-emphasis and post-emphasis circuits so that the high frequency components of the data signal are not clipped by the limiter. In another embodiment, the limiter circuit is bypassed selectively when a data signal is transmitted. In an alternative embodiment, a pilot tone is combined with the incoming data signal. The characteristics of the pilot tone are such that amplitude of the pilot tone is constant and always sets the gain of the limiter, thereby keeping the gain of the limiter circuit constant.Type: GrantFiled: November 3, 1993Date of Patent: April 9, 1996Assignee: Celeritas Technologies, Ltd.Inventor: Michael G. Dolan
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Patent number: 5438684Abstract: A dual-mode RF signal power amplifier combining network is comprised of two branches, each having a power amplifier (200 and 201). The first branch contains a non-linear mode power amplifier (200) while the second branch contains a linear mode power amplifier (201). The non-linear mode branch also has an RF switch (210). Both branches are coupled to a common output node (220). The common node (220) is coupled to a filter (107) before going to an antenna (106). The non-linear mode power amplifier (200) operates when an FM signal is to be amplified, while the linear amplifier (201) is biased in an off state. The linear mode power amplifier (201) operates when a digital signal is to be amplified, while the non-linear amplifier (200) is biased in an off state. The RF switch (210) removes the non-linear amplifier (200) from the circuit to prevent loading the on state linear amplifier (201).Type: GrantFiled: March 10, 1994Date of Patent: August 1, 1995Assignee: Motorola, Inc.Inventors: Dale G. Schwent, Rashid M. Osmani, Robert N. Weisshappel
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Patent number: 5436930Abstract: An analog signal is added to a data signal that specifies a symbol in a symbol constellation to produce a combined signal that is transmitted to a receiver. The symbol constellation is picked from a plurality of symbol constellations having differing symbol densities based on the amplitude of the analog signal.Type: GrantFiled: June 14, 1993Date of Patent: July 25, 1995Assignee: AT&T Corp.Inventors: Gordon Bremer, Kenneth D. Ko, Luke J. Smithwick
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Patent number: 5423078Abstract: The present invention relates generally to RF power amplifiers for portable cellular radiotelephones, and more particularly, to dual-mode cellular radiotelephones. A power supply network enables the RF power amplifier in a dual-mode radiotelephone to operate with two separate modes: saturated and unsaturated. Switches in the power supply network, e.g. complementary transistors, are driven to a first set of logic states by a square wave which is synchronized with transmit time slots present in a TDMA frame structure to charge a capacitor from a battery. When the switches are then driven to a second set of logic states, the capacitor is placed in series with the battery to essentially double the supply voltage. When the radiotelephone operates in a digital mode, the increased supply voltage coincides with the transmit time slot and temporarily increases the saturation point of the RF power amplifier to permit linear amplification.Type: GrantFiled: March 18, 1993Date of Patent: June 6, 1995Assignee: Ericsson GE Mobile Communications Inc.Inventors: Darrell Epperson, Paul W. Dent
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Patent number: 5423074Abstract: A power amplifier used in a portable, radio frequency transmitter is switched between different modes of operation when transmitting differently modulated carriers. The first mode of operation corresponds to amplitude modulation (AM), while a second mode corresponds to angle modulation techniques such as frequency modulation (FM). A switching network alters the impedance of the power amplifier to match network for matching the impedance of the transmitter antenna in order to achieve maximum efficiency in each mode of operation. Various switching methods and impedance matching circuits are disclosed.Type: GrantFiled: April 11, 1994Date of Patent: June 6, 1995Assignee: Ericsson GE Mobile Communications Inc.Inventor: Paul W. Dent
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Patent number: 5392463Abstract: A power amplifier used in a mobile radio apparatus operated selectively in an analog mode and a digital mode comprises an amplifying circuit for saturation-amplifying and linear-amplifying a speech signal and a switch for selectively switching the amplifying circuit to a saturation amplification and a linear amplification in accordance with the analog mode and the digital mode.Type: GrantFiled: October 16, 1991Date of Patent: February 21, 1995Assignee: Kabushiki Kaisha ToshibaInventor: Tatsuya Yamada
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Patent number: 5369637Abstract: A signal transmission system, for example a TDMA system, in which a carrier is divided into a plurality of traffic signal time slots, with optionally, some regularly interspersed control signal time slots. In order to be able to provide flexibility in the symbol rates and/or modulation schemes used by complementary users, the traffic signal time slots have one of at least two predetermined durations. However irrespective of the duration(s) of the traffic signal time slots, the number of symbols per traffic signal time slot remains substantially the same.Type: GrantFiled: March 25, 1992Date of Patent: November 29, 1994Assignee: U.S. Philips CorporationInventors: Andrew J. Richardson, Peter J. Mabey
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Patent number: 5361403Abstract: A power amplifier used in a portable, radio frequency transmitter is switched between different modes of operation when transmitting differently modulated carriers. The first mode of operation corresponds to amplitude modulation (AM), while a second mode corresponds to angle modulation techniques such as frequency modulation (FM). A switching network alters the impedance of the power amplifier to match network for matching the impedance of the transmitter antenna in order to achieve maximum efficiency in each mode of operation. Various switching methods and impedance matching circuits are disclosed.Type: GrantFiled: May 17, 1993Date of Patent: November 1, 1994Assignee: Ericsson GE Mobile Communication Holding, Inc.Inventor: Paul W. Dent
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Patent number: 5251331Abstract: The dual mode power amplifier apparatus of the present invention is comprised of a number of power amplifiers (101-103) coupled to a voltage convertor (104) through their collector supply lines. A mode select line (105) is connected to the voltage convertor (104) to select a digital or analog mode. The preferred embodiment of the present invention is used in a hybrid digital/analog radiotelephone. In the digital mode, the voltage convertor (104) is turned off and the voltage convertor (104) supply voltage is allowed through to the collectors of the power amplifiers (101-103). This permits the power amplifiers (101-103) to operate with optimum linearity in a digital transmission environment. In an analog environment, the voltage convertor (104) is on and supplying a reduced voltage to the power amplifiers (101-103) allowing more efficient operation in this mode.Type: GrantFiled: March 13, 1992Date of Patent: October 5, 1993Assignee: Motorola, Inc.Inventors: Dale G. Schwent, Rashid M. Osmani, Gary M. Cristiano
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Patent number: 5249302Abstract: A radiotelephone system comprised of a radiotelephone-pair suitably intercoupled theretogether to permit transfer of data, such as NAM information, therebetween. A first of the radiotelephone-pair comprises a radiotelephone of conventional construction. A second radiotelephone of the radiotelephone-pair comprises a radiotelephone having circuitry to transmit efficiently an information signal upon a cellular, communication system of increased capacity. The data sequence contained in the first radiotelephone is transferred to the second radiotelephone to permit a communication link to be formed between the second radiotelephone and a cellular, communication network.Type: GrantFiled: February 11, 1991Date of Patent: September 28, 1993Assignee: Motorola, Inc.Inventors: Michael P. Metroka, Joshua P. Kiem
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Patent number: 5214787Abstract: A microwave system is provided for the broadcast of multiple channels of audio programming to a wide listener base, in which noise-free transmission of multiple audio channels is accomplished through microwave transmission followed by down converting the received signal to television band frequencies, accomplished in one embodiment through the use of a single MDS channel.Type: GrantFiled: August 31, 1990Date of Patent: May 25, 1993Inventor: Frank P. Karkota, Jr.
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Patent number: 5179360Abstract: Upon transmission, when the digital transmission mode is set, an analog audio signal is A/D converted, the digital audio signal is coded, a first carrier is modulated by the coded signal and multiplied by a first multiplier, and the multiplied signal is sent to an orthogonal modulating and D/A converting circuit. When the analog transmission mode is set, a second carrier is modulated by the digital audio signal and multiplied by a second multiplier, and the multiplied signal is sent to the orthogonal modulating and D/A converting circuit. A signal of a frequency which is equal in both of the digital transmission mode and the analog transmission mode is given to the orthogonal modulating and D/A converting circuit. Upon reception, when the digital transmission mode is set, an output of an A/D converting and orthogonal demodulating circuit is frequency divided by a first frequency divider and demodulated and decoded.Type: GrantFiled: March 20, 1992Date of Patent: January 12, 1993Assignee: Sony CorporationInventor: Mitsuhiro Suzuki
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Patent number: 5175871Abstract: In a cellular telephone of the type capable of operating in both analog and digital modes, a power amplifier is provided which can operate efficiently in both the analog and digital modes of operation. The power amplifier includes a non-linear power amplifier stage and a linear power amplifier stage which are controlled by a switching means. During the analog mode of operation, the switching means causes the non-linear amplifier stage to amplify the RF signals. During the digital mode of operation, the non-linear amplifier amplifies the RF signal when there is a requirement for a relatively low power output. During the digital mode when there is a requirement for a relatively high level output, the switching means causes the non-linear power stage and the linear power stage to amplify the RF signals.Type: GrantFiled: August 8, 1991Date of Patent: December 29, 1992Assignee: Ericsson/GE Mobile Communication Holding Inc.Inventor: L. P. Kunkel
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Patent number: 5168516Abstract: A radio telephone system of the multi-channel access type using an empty channel selected from a plurality of channels for radio telephone communication of voice audio or data signals and a method of controlling such a radio telephone system. The method and apparatus can improve the data communication quality without reducing the number of available channels. A switching circuit is provided in at least one of the base unit and the radio telephone for changing the frequency characteristic of the signal to be transmitted when the signal is a data signal.Type: GrantFiled: March 23, 1990Date of Patent: December 1, 1992Assignee: Kabushiki Kaisha ToshibaInventor: Koichi Ito
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Patent number: 5081647Abstract: A method and apparatus for communicating a voice conversation over a single telephone channel using continuously variable level quadrature amplitude modulation establishes and maintains two totally independent communication paths, each near perfect in amplitude and phase with respect to frequency over a bandwidth suitable for communication of continuously variable amplitude pulses. These pulses may be representations of any suitable bandlimited analog signal. The method establishes almost flawless QAM channels (real, imaginary), then allows switching to continuously variable amplitude analog transmissions.Type: GrantFiled: January 6, 1989Date of Patent: January 14, 1992Assignee: American Telephone & Telegraph CompanyInventor: Gordon Bremer
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Patent number: 5060294Abstract: A dual mode power amplifier operable in etiher the linear mode or the saturation mode. The power amplifier, when comprising a portion of a radio transmitter, permits efficient amplification of either a frequency modulated or a composite modulated signal by operation of the amplifier in the saturation mode or the linear mode, respectively. A processor determines the modulation-type of the signal and generates a signal to cause operation of the amplifier in either the saturation mode or the linear mode.Type: GrantFiled: July 5, 1990Date of Patent: October 22, 1991Assignee: Motorola, Inc.Inventors: Dale G. Schwent, Rashid M. Osmani, Gary M. Cristiano
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Patent number: 4994757Abstract: Circuitry changes the magnitude of power supply voltages to correspond to the desired level of a variable output power. This maximizes the electrical power efficiency of amplifiers. The circuitry also provides for automatic control of the amplitude of the amplifier output signal.Type: GrantFiled: November 1, 1989Date of Patent: February 19, 1991Assignee: Motorola, Inc.Inventors: Robert H. Bickley, Richard A. Bory
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Patent number: 4875039Abstract: A paging network is disclosed which utilizes a plurality of distributed switches to transmit pages on a non-real time basis to achieve efficient and low cost transmission. Each of the switches processes packets of pages received from the network. Each of the switches also processes pages into packets of pages to be transmitted to another switch in the network or into batches of pages to be transmitted by a local paging service if the switch is a local switch. The network dynamically programs the reception channel(s) of the paging receivers in response to traffic conditions of a local switch or in accordance with service options specified by a subscriber to a local paging service. The digits of the paging receiver identification code are transmitted in an order of increasing significance to conserve battery life of the paging receivers. Pages may be initiated by placing a local call to any lata switch in the network and service options may be varied by placing of a local call to a lata switch.Type: GrantFiled: February 22, 1988Date of Patent: October 17, 1989Assignee: Telefind Corp.Inventors: Andrew A. Andros, Thomas J. Campana, Jr., Gary F. Thelen, Robert A. Kinast
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Patent number: 4757519Abstract: A programmable premodulation filter having a finite impulse response to digitally filter a digital data signal to provide a modulation signal for modulating an RF carrier signal is described. A digital summer and accumulator are programmed to provide a finite impulse response to a bimodal impulse signal which represents the input digital data signal. Several impulse response functions g(t) are stored in a ROM (or RAM) and may be selected to reprogram the digital filter to provide a desired modulation format. When a RAM is used, additional impulse response functions may be input to the RAM and the stored impulse response functions may be dynamically modified to provide the desired modulation format.Type: GrantFiled: October 2, 1987Date of Patent: July 12, 1988Assignee: Hewlett-PackardInventors: Robert R. Collison, Michael T. Wende, Raymond A. Birgenheier
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Patent number: 4731796Abstract: A multi-mode radio transceiver comprising a sequence of bi-directional circuit modules including a radio frequency input/output amplifier module (1), a radio frequency/baseband I and Q quadrature channel conversion module (2), an analogue/digital conversion module (3), a digital signal processor (4,5), and a digital signal input/output interface (6), with a control means (7) whereby for transmission a radio frequency signal is formed from analogue quadrature I and Q channel components of a digitized signal at baseband and translated to the radio transmission frequency and for reception the radio frequency signals are transformed into I and Q quadrature analogue components at baseband and subsequently digitized.Type: GrantFiled: June 19, 1987Date of Patent: March 15, 1988Assignee: STC, plcInventors: John Masterton, Peter A. Ramsdale
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Patent number: 4715046Abstract: A frequency agile signal generator provided for emulating a communication signal of predetermined frequency and modulation characteristics including frequency hopping. The signal generator includes a digital controller such as a microprocessor or microcomputer for generating digital command signals specifying the desired characteristics of the output signal. In response to the digital command signals, a base digital frequency signal representing the desired base or center frequency of the output signal is generated by a number controlled oscillator in response to a digital frequency control signal. The digital command signals also control the generation of an analog modulation signal having desired modulation characteristics.Type: GrantFiled: June 20, 1986Date of Patent: December 22, 1987Assignee: Science Applications International CorporationInventors: Charles W. True, III, John K. Brady
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Patent number: 4686490Abstract: A digital modulator for selectably generating differential phase shift keyed (PSK) data signals and frequency shift keyed (FSK) data signals is disclosed. A clock generator (10) provides carrier frequency clock signals and a plurality of phase-shifted high frequency clock signals. A CLX generator (11) selects the proper PSK or FSK carrier clock. A data scrambler (17) accepts a serial data input stream and provides the scrambled dibit to the dibit encoder (12). The dibit encoder (12) converts the scrambled dibit into two phase-shifting control signals. A three-tap finite impulse response filter (13) generates carrier phase signals by splitting each cycle of the selected carrier clock into eight phases, and, for PSK operation, provides phase shifting in response to the two phase-shifting control signals. A multiplexer (14) selects one of the phase-shifter high frequency clocks in response to the carrier phase signals.Type: GrantFiled: April 7, 1986Date of Patent: August 11, 1987Assignee: Hayes Microcomputer Products, Inc.Inventor: John R. Cressey
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Patent number: 4418404Abstract: An apparatus and method of transmitting and receiving information underwa assure improved performance characteristics. Modulating a carrier and appropriately filtering it allows the transmission of only single sideband signals or a carrier along with single sideband signals to increase the range at reduced power consumption levels. Demodulating incoming signals can be done synchronously (when the carrier is present) or asynchronously (only single sideband signals) to extract the information. When a number of carriers are modulated and, simultaneously, are transmitted and received, the system's reliability is enhanced.Type: GrantFiled: October 1, 1981Date of Patent: November 29, 1983Assignee: The United States of America as represented by the Secretary of the NavyInventors: Alan Gordon, Stanley J. Watson, Steven J. Cowen, Gerald Mackelburg, Brett D. Castile
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Patent number: 4296400Abstract: An installation for the control of a traffic light system by means of vehicles which are equipped with devices for automatic determination of position, i.e. bearing determination, and which includes therefore a first, transmission/reception antenna having a transmission direction perpendicular to the direction of travel for the transmission of bearing information, and a second antenna, arranged to transmit in the direction of travel, for the transmission of transfer messages or commands for control of lights of such a traffic light system. Means are also provided for selectively determining the type of signals to be transmitted and the corresponding antenna for such transmission.Type: GrantFiled: November 28, 1978Date of Patent: October 20, 1981Assignee: Siemens AktiengesellschaftInventors: Becker Friedbert, Johann Steinkamp, Klaus Koenen