Abstract: An FM transmitter and power supply/charging assembly electrically coupleable with an MP3 player. The assembly includes a modular docking unit having a main body portion with a docking cavity therein, wherein the main body portion contains the FM transmitter and power/charging circuitry, with coupling means in the docking cavity for connecting the MP3 player with the FM transmitter and power/charging circuitry, to accommodate FM transmission by the FM transmitter of audio content when played by the MP3 player in the docking cavity of the modular docking unit, and adapted for transmitting electrical power through the modular docking unit and the power/charging circuitry therein, for charging of a battery of the MP3 player and/or powering of the MP3 player.

Abstract: A wireless audio signal transmitter device capable of automatically and dynamically locking a working frequency for a wireless channel thereof with respect to a wireless audio playing device and a method therefore are disclosed. In locking a wireless channel associated with a working frequency, the wireless audio signal transmitter device automatically and dynamically transmits a sequence of at least a wireless audio signal to the wireless audio playing device. Upon a specific one of the sequence of at least a wireless audio signal having a communication frequency matching with a working frequency of the wireless audio playing device, a sound is played by the wireless audio playing device and received by the wireless audio signal transmitter device. Then, the wireless audio signal transmitter device locks its wireless channel based on the knowledge of the working frequency of the wireless audio playing device.

Abstract: An FM transmitter and power supply/charging assembly electrically coupleable with an MP3 player. The assembly includes a modular docking unit having a main body portion with a docking cavity therein, wherein the main body portion contains the FM transmitter and power/charging circuitry, with coupling means in the docking cavity for connecting the MP3 player with the FM transmitter and power/charging circuitry, to accommodate FM transmission by the FM transmitter of audio content when played by the MP3 player in the docking cavity of the modular docking unit, and adapted for transmitting electrical power through the modular docking unit and the power/charging circuitry therein, for charging of a battery of the MP3 player and/or powering of the MP3 player.

Abstract: A multiband and multimode transmitter circuit (200) includes two separate oscillators, such as at least a first oscillator circuit (60), a second oscillator circuit (62), a corresponding first signal processing circuit (64), and second signal processing circuit (66) to produce a first output frequency signal (78) defined within the first or second band of frequencies in response to a transmitter input signal (46). Each oscillator and corresponding signal processing circuit (64, 66) may be optimized for the lowest power consumption while meeting the noise performance criteria in each of the multiple frequency bands. The multiband and multimode transmitter circuit (200) may produce the transmitter output signal (36) with either linear modulation or nonlinear modulation and at a first band or second band frequencies.

Abstract: In a foldable cellular phone, an image taken and provided by a camera portion is displayed on a first or second display portion for previewing before storage in a third memory. The second display portion displays the image in the opposite directions corresponding to a folded state and an open state, respectively. In either the folded state or the open state, a second display driver portion rotates the image by 180 degrees to display the image on the second display portion for previewing. Although the direction of the image displayed on the second display portion is inverted depending on the state selected between the folded state and the open state, the second display portion displays the image in a constant direction with respect to a user in both the folded state and the open state of the cellular phone during the previewing operation.

Abstract: The present invention, generally speaking, provides for high-efficiency power control of a high-efficiency (e.g., hard-limiting or switch-mode) power amplifier in such a manner as to achieve a desired modulation. In one embodiment, the spread between a maximum frequency of the desired modulation and the operating frequency of a switch-mode DC—DC converter is reduced by following the switch-mode converter with an active linear regulator. The linear regulator is designed so as to control the operating voltage of the power amplifier with sufficient bandwidth to faithfully reproduce the desired amplitude modulation wave-form. The linear regulator is further designed to reject variations on its input voltage even while the output voltage is changed in response to an applied control signal. This rejection will occur even though the variations on the input voltage are of commensurate or even lower frequency than that of the controlled output variation.

Abstract: A mobile telephone apparatus is disclosed in which a solar power source is used to supplement battery power. A solar cell array is positioned on the surface of the telephone and supplies electric current to the telephone. A preferred embodiment of the present invention is equipped with speech recognition software that allows the user to issue commands (such as dialling the telephone) verbally to the telephone. In addition, this speech recognition may be used to operate an integrated AM/FM broadcast radio to allow the telephone to double as a radio. In an alternative embodiment, the solar mobile telephone is integrated into a headset to allow for convenient hands-free operation.

Abstract: A system and method for controlling a transverter from a wireless modem unit (WMU). A WMU delivers a control signal to a transceiver. This signal is outside the IF signal data range (preferably below 11 MHz). The signal is carried on the cable between the transceiver and the WMU. This signal is detected by the transceiver, and determines the timing and the control information. The signal is ASK modulated to enable low data rate transfer of messages between the WMU and the transceiver. The control signal is detected at the transverter using a detector circuit. Additionally, specific transverter detection circuits are disclosed to detect the control signal.

Abstract: The power amplification circuit for a communication device includes an initial-stage amplifier for amplifying a modulation signal of a predetermined frequency band, a first amplification system having a subsequent-stage amplifier and a final-stage amplifier for amplifying power of an amplified output of the initial-stage amplifier without modification and outputting the amplified output as a first transmission signal, and a second amplification system having a frequency conversion circuit composed of a local oscillation circuit and a mixing circuit for converting an amplified output of the initial-stage amplifier into a signal of a frequency band different from that of the first transmission signal and a subsequent-stage amplifier and a final-stage amplifier for amplifying power of an output signal of the frequency conversion circuit and outputting the amplified output as a second transmission signal.

Abstract: A radio transmitter includes a CPU, functioning to allow the radio signal to be transmitted in event of a decision result that the radio signal transmission should be permitted but, in event of a decision result that the radio signal transmission should not be permitted, functions to allow the radio signal to be stopped and to instruct the alarm output section to output an abnormal alarm; a distributor, functioning to distribute a radio signal outputted from the radio transmitter to the outside; a transmitter; a spectral analysis, functioning to perform a frequency analysis of the radio signal according to the standard information; a power comparator section, to decide whether or not a transmission of the radio signal should be permitted by comparing the result of the frequency analysis with the standard information; and an alarm output section.

Abstract: An Electromagnetic Field Communications System for Wireless Networks for producing an electromagnetic field within a structure is disclosed. The electromagnetic field is produced by using common conductive elements already present within virtually all pre-existing residential commercial, industrial buildings. These conductors, which may include electrical ground shields, wiring, pipes, sprinkler conduits or structural members, are excited with a signal, and become the cavity which contains the electromagnetic field. In preferred embodiments of the invention, signals are generated using the High Frequency, Very High Frequency and lower UHF bands (3 to 30, 30 to 300 and up to 400 MHz). The invention may be used to create a local area network inside the field and within the structure. Devices that include receivers tuned to the electromagnetic field may then be connected and networked.

Abstract: In a method of operating a remote control system and in such a system comprising an RF transmission and receiving system and an IR transmission device the sub-carrier information of the IR signal is transmitted in the RF signal in a signal separate from the envelope information of the IR signal which is contained in a envelope signal.

Abstract: A sinusoidal RF carrier is modulated for the transmission of digital binary data streams through the amplitude suppression of carrier wavelets. These wavelets are defined between zero crossover positions representing zero energy locations. This modulation is accomplished when the carrier is slightly amplitude modulated with a modulation signal that is equal in frequency to the carrier itself and the modulation always begins or ends upon the exact zero voltage crossing point of the RF cycle phase. The modulation is applied as a slight shift of the amplitude of any single cycle, each cycle representing a single bit of data. A single cycle of RF will either represent a “1” or “0” depending upon the amplitude of the cycle, relative to other adjacent cycles in the same carrier.

Abstract: A radio frequency power amplifier circuit provides linear amplitude modulation of a radio frequency output signal while operating in a saturated amplification mode. The power amplifier circuit incorporates a lossy modulator that functions as a variable resistance responsive to an amplitude modulation signal. A supply voltage is coupled to the voltage supply input of the power amplifier circuit through the lossy modulator, such that the supply voltage applied to the power amplifier varies with the amplitude modulation signal. The radio frequency power amplifier circuit modulates the envelope of an RF output signal generated by saturated mode amplification of a constant envelope radio frequency input signal.

Abstract: A system and method for providing a highly efficient linear transmitter compatible with a radio capable of operating in one of several modes. In a normal mode of operation, the radio frequency power amplifier (RFPA) runs in envelope tracking mode. Accordingly, the RFPA supply voltage follows the envelope of the linear modulation. In an alternate mode of operation, the supply modulator is locked to a fixed DC voltage. A high efficiency level is maintained in both the normal mode and the alternate mode by using a single agile DC-DC converter to supply the RFPA. The converter input voltage is switched depending on the mode of operation.

Abstract: A method and circuitry for a transmitter is disclosed. The transmitter is adapted for transmission of signals based on at least two different transmission modes. In the method a signal to be transmitted in accordance with a selected transmission mode is input in a single path (1) comprising amplifier means (10). Based on the selected transmission mode, the waveform of the signal is shaped by combining at least two waveforms. The mode of at least one component on the signal path is switched between said at least two transmission modes by means of a switching circuit (50).

Abstract: A cellular radio communication system is provided for transmitting data over a plurality of transmission links. The system includes means for generating a modulated signal by applying a constant amplitude envelope modulation scheme to data to be transmitted across poor quality transmission links and amplifier means for non-linearly amplifying the modulated signal. The system can additionally include means for generating a second modulated signal by applying an amplitude dependent modulation scheme to data to be transmitted across higher quality transmission links and amplifier means for linearly amplifying the second modulated signal. Using a constant amplitude envelope modulation scheme, such as GMSK or MLCAM for poorer quality links means that for these links signals can be amplifier non-linearly at higher gains.

Abstract: A Power Amplifier (PA) exhibits non-linear characteristics as a result of Amplitude Modulation-Phase Modulation (AM-PM) conversions resulting in intermodulation. Inter-modulation affects the RF signal spectrum at the output of the PA. The invention presents a method and apparatus for reducing intermodulation generated at the output of a PA as a result of AM-PM conversion. Presented is a RF power detector utilized in feedback control circuitry where the induction of odd-order harmonics into the feedback path acts to reduce AM-PM intermodulation at the output of the PA. The RF power detector comprises an detector input for receiving RF power and a detector output containing a pre-corrected detected voltage. The RF power detector comprises a pre-correcting circuit for generating odd-order harmonics at a specific power level. The pre-correcting circuit induces odd-order harmonics into the detected portion of output power allowing feedback control circuit to compensate for AM conversions.

Abstract: An FM transmitter and power supply/charging assembly electrically coupleable with an MP3 player. The assembly includes a modular docking unit having a main body portion with a docking cavity therein, wherein the main body portion contains the FM transmitter and power/charging circuitry, with coupling means in the docking cavity for connecting the MP3 player with the FM transmitter and power/charging circuitry, to accommodate FM transmission by the FM transmitter of audio content when played by the MP3 player in the docking cavity of the modular docking unit, and adapted for transmitting electrical power through the modular docking unit and the power/charging circuitry therein, for charging of a battery of the MP3 player and/or powering of the MP3 player.

Abstract: A frequency tracking and locking system of a wireless microphone has a frequency selection unit selecting a predetermined frequency and outputting the predetermined frequency to the frequency data storage unit, a frequency data storage unit storing a predetermined frequency data and outputting the predetermined frequency data to the data encoding unit, the data encoding unit encoding the predetermined frequency data and outputting the predetermined frequency data to the infrared modulation transmitter, an infrared modulation transmitter transforming the predetermined frequency data to the infrared frequency data and transmitting the infrared frequency data to the data decoding unit, a data decoding unit decoding the infrared frequency data to a first radio frequency and outputting the first radio frequency to the frequency transformation unit, a frequency transformation unit transforming the first radio frequency to a second radio frequency and outputting the second radio frequency to the radio emission unit,

Abstract: A transmitter adopting a polar loop system including a phase control loop for controlling the phase of a carrier signal outputted from a transmitting oscillator and an amplitude control loop for controlling the amplitude of a transmitting output signal outputted from a power amplification circuit, and designed to be capable of performing transmission using a GMSK modulation mode and transmission using an 8-PSK modulation mode. In the transmitter, the phase control loop is shared as a phase control loop for use in the GMSK modulation mode and a phase control loop for use in the 8-PSK modulation mode. A component similar to any one of components constituting a loop filter is provided in parallel therewith so that the component can be connected or disconnected in accordance with the modulation mode, for example, by use of a switching element.

Abstract: Circuitry that generates an interface signal between a first and a second integrated circuit (IC). The circuitry includes a reference circuit that provides a reference signal, an interface circuit, and a circuit element. The interface circuit is implemented on the first IC, operatively couples to the reference circuit, receives the reference signal and a data input, and generates the interface signal. The circuit element is implemented on the second IC, operatively couples to the control circuit, receives the interface signal, and provides an output signal. The reference signal can be a voltage or a current signal, and can be generated in the first or second IC. The interface circuit can be implemented with a current mirror coupled to a switch array, and can be oversampled to ease the filtering requirement. The interface signal can be a differential current signal having multiple (e.g., four, eight, or more) bits of resolution. The circuit element can be, for example, a VGA, a modulator, or other circuits.

Abstract: An FM transmitter and power supply/charging assembly electrically coupleable with an MP3 player. The assembly includes a modular docking unit having a main body portion with a docking cavity therein, wherein the main body portion contains the FM transmitter and power/charging circuitry, with coupling means in the docking cavity for connecting the MP3 player with the FM transmitter and power/charging circuitry, to accommodate FM transmission by the FM transmitter of audio content when played by the MP3 player in the docking cavity of the modular docking unit, and adapted for transmitting electrical power through the modular docking unit and the power/charging circuitry therein, for charging of a battery of the MP3 player and/or powering of the MP3 player.

Abstract: Power amplifier mode control and an associated switching arrangement permit a wireless communications device, such as a mobile terminal, to advantageously use the same transmitter power amplifier in both digital and analog operating modes. Analog mode requires the mobile terminal to operate its receiver and transmitter in full-duplex mode, thus requiring a duplexer for separating the receive signal from the transmit signal. Digital mode requires the mobile terminal to operate its receiver and transmitter in half-duplex mode, eliminating the need for the duplexer. In a basic implementation, the mobile terminal includes a switching arrangement allowing the duplexer to be switched in and out of the power amplifier transmit path. For reasons of signal requirements and operating efficiency, the mobile terminal adjusts the operating point of the power amplifier such that it operates linearly or quasi-linearly when in the mobile terminal is in digital mode.

Abstract: A digital communication system and method is provided for increasing bit-rates while maintaining the reliability of transmitted digital information and avoiding increased power demands. The communication system includes a transmitter that modulates one or more bits onto a carrier signal to generate and transmit a first transmission signal during the first part of a pulse time TB, receives an additional bit, and based on the value of the additional bit, either transmits the first transmission signal again during the second part of the pulse time TB or transmits a second transmission signal during the second part of the pulse time TB.

Abstract: The present invention provides an improved receiver capable of receiving either a satellite broadcast signal or a cable TV signal associated with a TV. The inventive receiver comprises a first BPF for filtering received broadcast signals, a first local oscillator for generating a first oscillation signal, a first mixer for generating a first IF signal, a SAW filter producing a waveformed band signal, a second local oscillator, for generating a second and a third oscillation signal, a second mixer for generating a second and a third IF signal, a switching block for switching the second and the third IF signal, a second BPF for producing a baseband channel signal selected from the cable TV signal, a first LPF for producing a baseband I signal of satellite broadcast channel, a shifter for shifting a phase of the third IF signal, a third mixer for generating a phase-shifted third oscillation signal, and a second LPF for producing a baseband Q signal of satellite broadcast channel.

Abstract: An apparatus is provided capable of wirelessly receiving an RF signal having a modulation frequency outside the AM and FM band and containing baseband audio content, such as Internet audio content, converting the signal to an RF modulated signal having a modulation frequency within the AM and/or FM band, and transmitting the RF modulated signal having a modulation frequency within the AM and/or FM band to a conventional AM/FM radio or stereo equipment to audibly reproduce the baseband audio content. The apparatus is also capable of receiving a hardwired signal including audio content, such as an Internet audio signal, modulate the audio content to an RF modulated signal having a modulation frequency within the AM and/or FM band, and transmitting the RF modulated signal to a conventional AM/FM radio or stereo equipment to audibly reproduce the audio content.

Abstract: The present invention is related to a system which comprises a number of transmitting microcells sequentially disposed and integrated along the road. The system developed, the aim of which is helping drivers by supplying them with useful information on the route they shall follow, comprises a number of repeating stations wherein each of them is provided with a “Fi” frequency receiving antenna which is interconnected to a “Fi” frequency transceptor for “FM”, and the latter is interconnected to a 87.9 Mz directional antenna through low loss cables.

Abstract: A method and apparatus for transmitting in multiple radio frequency (RF) bands from a single device is described. The device includes a transmitter (128) for transmitting RF communication signals. The transmitter is comprised of a power amplifier (200) for amplifying the RF communication signal in either a first RF band or a second RF band. The transmitter has a complex transformer (202) for partially transforming the impedance of the RF communication signal in a first RF band, and completely transforming the impedance of the RF communication signal to the characteristic impedance in a second RF band. The transmitter also includes a first path (204) for transmitting the RF communication signal in the first RF band and a second path (206) for transmitting the RF communication signal in the second RF band.

Abstract: A modulation mixer includes a low cost circuit for reducing a carrier frequency leak. An orthogonal modulator including the modulation mixer may be formed on a single silicon substrate and does not need to be connected to an external transformer to suppress carrier frequency leak.

Abstract: The power amplification circuit for a communication device includes an initial-stage amplifier for amplifying a modulation signal of a predetermined frequency band, a first amplification system having a subsequent-stage amplifier and a final-stage amplifier for amplifying power of an amplified output of the initial-stage amplifier without modification and outputting the amplified output as a first transmission signal, and a second amplification system having a frequency conversion circuit composed of a local oscillation circuit and a mixing circuit for converting an amplified output of the initial-stage amplifier into a signal of a frequency band different from that of the first transmission signal and a subsequent-stage amplifier and a final-stage amplifier for amplifying power of an output signal of the frequency conversion circuit and outputting the amplified output as a second transmission signal.

Abstract: A power amplifier circuit has a driver amplifier stage including a low band driver amplifier and a high band driver amplifier. A final amplifier stage includes a linear mode amplifier for amplifying digitally modulated signals and a saturated (nonlinear) mode amplifier for amplifying frequency modulated (analog) signals. A switching network interconnects the driver amplifier stage and the final amplifier stage. Depending on the desired mode of operation, an appropriate driver amplifier can be coupled to an appropriate final amplifier to most effectively and efficiently amplify analog or digital RF signals in either of a plurality of frequency bands. A diplex matching circuit is coupled to the linear mode final amplifier for impedance matching and for separating D-AMPS (800 MHz band) and PCS (1900 MHz band) digital signals. A power impedance matching circuit is coupled to the output of the saturated mode final amplifier.

Abstract: An apparatus for communicating, over a single transmission medium, two signals of substantially the same center frequency. The apparatus offsets in frequency one of the signals by combining the signal with the signal from a local oscillator. The apparatus then transmits the two signals, one offset from the other, as well as the signal from the local oscillator to allow for recovery of the two signals with a precise correction for the offset. In particular, the transmission medium is an optical fiber and the two signals are a main RF signal and a diversity RF signal received, respectively, by a main element and a diversity element of a diversity antenna system. The invention is of use, for example, in providing to a microbase station a main RF signal and its diversity RF signal received at a diversity antenna system remote from the microbase station and connected to the microbase station by an optical fiber.

Abstract: A method and a circuit for high-efficiency linear RF-power amplification over a wide range of amplitudes from zero to peak output includes a final RF-power amplifier operating at or near saturation, an RF driver amplifier, a high-level amplitude modulator for the final amplifier, preferably a high-level amplitude modulator for the driver amplifier, and a means for determining the supply-voltage input to the final amplifier and for controlling the amplitude of the drive. The means for determining the supply-voltage input and for controlling the amplitude acts so that the final amplifier drive varies from a minimum level to peak as the desired transmitter output varies from zero to peak. The transmitter is preferably of the envelope-elimination-and-restoration type or the envelope-tracking type.

Abstract: The invention provides an apparatus and procedure for radio transmission of information using a middle channel, a first side channel and a second side channel. The transmitted middle channel is FM-modulated by a suitable frequency. A signal symmetrically amplitude-modulated with respect to the center frequency of the middle channel is generated, and a first amplitude-modulated single side band (LSB) and a second amplitude-modulated single side band (USB) are formed from the amplitude-modulated signal. The first single side band (LSB) is modulated by the information in the first side channel to form two side bands for the first single side band, and the second single side band (USB) is modulated by the information in the second side channel to form two side bands for the second single side band. The middle channel FM signal, the modulated first single side band (SSB) and the second modulated single side band (SSB) are then combined in a combiner for simultaneous transmission of all three channels.

Abstract: A power amplifier circuit has a driver amplifier stage including a low band driver amplifier and a high band driver amplifier. A final amplifier stage includes a linear mode amplifier for amplifying digitally modulated signals and a saturated (nonlinear) mode amplifier for amplifying frequency modulated (analog) signals. A switching network interconnects the driver amplifier stage and the final amplifier stage. Depending on the desired mode of operation, an appropriate driver amplifier can be coupled to an appropriate final amplifier to most effectively and efficiently amplify analog or digital RF signals in either of a plurality of frequency bands. A matching circuit is coupled to the linear mode final amplifier for impedance matching and for separating D-AMPS (800 MHz band) and PCS (1900 MHz band) digital signals. A power impedance matching circuit is coupled to the output of the saturated mode final amplifier.

Abstract: A multiple band mixer (204) includes at least one transistor element (313, 324, 400). A single local oscillator provides a signal to one terminal of the at least one transistor element. The communication signals for each frequency band is input to the at least one transistor element at another terminal. A third terminal of the at least one transistor element is connected to the output.

Abstract: A mobile satellite communication terminal capable of performing satellite communication both indoors and outdoors. In an indoor mode, the mobile satellite communication terminal includes an indoor terminal for carrying out transmission or reception of a signal through a ground radio link and a repeater terminal installed in such a location that the repeater terminal can get an unobstructed view of a satellite for carrying out transmission or reception of a signal through a satellite communication link. In an outdoor mode, an antenna of the indoor unit is replaced by an antenna for the satellite communication link, whereby the indoor terminal can be used as an outdoor terminal.

Abstract: A messaging receiver (400) and corresponding system (100b) and method adaptable to a plurality of modulation formats including; a processor (401) having flexible resources (404), preferably software based, for receiving a signal to provide a modulation identifier, and a controller (403), coupled to the processor, for deploying the flexible resources responsive to the modulation identifier. Alternatively the messaging receiver includes a buffer (412) for storing a signal having a modulation format, and the processor processes the signal in accordance with the plurality of modulation formats so as to differentiate the modulation format, and the controller deploys the flexible resources responsive to the modulation format.

Abstract: Information signal processing apparatus and method characterized in that an input information signal is converted into a transmission signal in a predetermined form and the converted transmission signal is transmitted by a selected one of a wire transmission and a radio transmission are provided. Information signal processing apparatus and method characterized in that either a wire reception to receive an information signal in a predetermined form through a transmission line or a radio reception to receive an information signal in which the information signal in the predetermined form was modulated and transmitted in a radio manner is selected and the received information signal in the predetermined form is reproduced are provided.

Abstract: A common transmit module of a programmable digital radio has a digital submodule which receives a bit stream and produces a modulated IF signal, and an analog submodule which receives the modulated IF signal and converts the modulated IF signal to a frequency corresponding to a specific type of radio function. The digital submodule includes (a) a sequential/parallel instruction set processor for signal processing and control, (b) a reconfigurable format unit, and (c) a modulator which receives the output signals of the reconfigurable format unit and produces the modulated oscillation signal.

Abstract: The present invention is directed towards an untethered microphone associated with a radio telephone base and adapted to provide wireless communication therebetween. The remote microphone may include a rechargeable battery and a solar power supply and associated panel configured to recharge the battery. The remote microphone and base unit are adapted to each transmit and receive data and control signals therebetween. The remote microphone is further adapted to transmit voice signals from the microphone to the base unit during operation. Typically, a first transceiver is located with the remote unit, and a second transceiver is located with the hands-free base unit. Working together, the transceivers carry the microphone's signals to the radio telephone's transmitter. Additionally, the transceivers carry call-in-progress information back and forth between the microphone and the hands-free base unit.

Abstract: A satellite system antenna/high frequency unit of a mobile terminal of the present invention is constructed with a satellite system antenna for a mobile satellite communication system and a satellite system high frequency circuit and a first interface is provided externally of a casing of the unit. A ground system antenna/high frequency unit is constructed with a ground system antenna for a mobile ground communication system and a ground system high frequency circuit and a second interface is provided externally of a casing of the unit. A radio control unit includes a circuit portion within a casing thereof for demodulating a receiving signal to an input intermediate frequency signal and modulating a transmission signal and converting it into an intermediate frequency signal. The radio control unit further includes a radio control interface and a set of switches provided externally of the casing and, in use, only one of the first and second interfaces is connected to the radio control interface.

Abstract: A circuit is provided for use in a dual mode mobile phone for selectively one of phase modulating or frequency modulating an RF signal. The circuit includes an IQ generator for generating one of first quadrature waveshapes or second quadrature waveshapes in response to a modulating signal; a quadrature mixer for mixing the first quadrature waveshapes or the second quadrature waveshapes with an RF signal to generate a phase modulated RF signal or a frequency modulated signal, respectively; and a limiter, such as at least one limiting amplifier, that has an input coupled to an output of the quadrature mixer for reducing an amplitude modulation component of only the frequency modulated signal. The at least one limiting amplifier has an input coupled to a limit control signal that has a magnitude selected for setting a dynamic range of the at least one limiting amplifier. The phase modulated signal may be a .pi./4-DQPSK signal.

Abstract: In a dual mode transmitter for modulating, in a digital mode, an input digital signal and transmitting a modulated digital signal and modulating, in an analog mode, an input analog signal and transmitting a modulated analog signal, a digital modulating section modulates the input digital signal to thereby generate the modulated digital signal, and outputs the modulated digital signal. An analog modulator/carrier generator modulates the input analog signal to thereby generate the modulated analog signal, and outputs it. Also, the analog modulator/carrier generator generates a carrier signal for up-converting the modulated digital signal. The up-converter up-converts, in the digital mode, the modulated digital signal by using the carrier signal and receives, in the analog mode, the modulated analog signal and passes it therethrough.

Abstract: A transmitting apparatus transmits at least one of a main and a supplementary modulated signal in response to a transmitting signal. The apparatus includes a first modulating circuit for modulating the transmitting signal in a main modulation system to produce the main modulated signal. The apparatus also includes a second modulating circuit for modulating the transmitting signal in a supplementary modulation system to produce the supplementary modulated signal. The apparatus further includes a selective supplying circuit for selectively supplying the transmitting signal to at least one of the first and second modulating systems. The apparatus also includes a control circuit connected to the first and second modulating circuits for controlling operation of the first and second modulating circuits and the selective supplying circuit.

Abstract: Some mobile station cellular networks use either amplitude modulation or constant envelope modulation depending on the situation. The pulsed transmitter of the mobile station is switched on and off by a first control signal (TXP) and the output power envelope shaping of the pulse to be transmitted is controlled in the feedback loop by a second control signal (TXC). According to the invention the output power is controlled by a third control signal (TXCE) which in the amplitude modulation case switches off the feedback loop for the period of the information transfer and which at other times closes the feedback loop.

Abstract: The dual mode amplifier network of the present invention enables a radiotelephone to operate efficiently in both the U.S. Digital Cellular mode and the FM analog cellular mode. Multiple, switched branches (110 and 120) permit one branch (110) with an isolator (103) to be used in the in the U.S. Digital Cellular mode while the other branch (120) is switched out. In the analog mode, the transmit filter branch (120) is used while the isolator branch (110) is switched out.

Abstract: An amplifier circuit (204) having a variable bandwidth comprises an amplifier (300), a capacitive element (304), a first npn transistor (302), and a switch control circuit (306). The first npn transistor (302) has a base coupled to an output terminal (205) of the amplifier (300), a collector coupled to a first reference voltage (113), and an emitter coupled to the capacitive element (304) and the switch control circuit (306). When the first npn transistor (302) is switched off by the switch control circuit (306), a first cutoff frequency is determined by a maximum operating frequency of the amplifier (300). When the first npn transistor (302) is switched on by the switch control circuit (306), a second cutoff frequency is determined by a capacitance of the capacitive element (304). For high frequency operation, the amplifier (300) includes at least a second npn transistor for amplification and the first cutoff frequency is determined by a Miller capacitance of the amplifier circuit (204).

Abstract: A dual-mode transmitter (100) adjusts a signal's deviation level when switched between a wideband mode and a narrowband mode of operation. The transmitter (100) automatically attenuates the deviation of the signal based on a ratio of the maximum deviation level for the wideband mode to the maximum deviation for the narrowband mode utilizing wideband/narrowband maximum deviation adjust circuitry (115). Because the attenuation based on the ratio of the maximum deviation levels is too large for a narrowband mode signal having average deviation, the signal is amplified based on a ratio of the average deviation level for the wideband mode to the average deviation for the narrowband mode utilizing wideband/narrowband average deviation adjust circuitry (103). Attenuation and amplification of the signal's deviation occur when the dual-mode transmitter (100) is operating in the narrowband mode.