Abstract: A translation loop signal upconverter is disclosed. Embodiments of the invention minimize nth order harmonics and spurious tones in the radio frequency output spectrum of a portable transceiver. In one embodiment, the invention is a signal upconverter, comprising a modulator configured to develop a modulated intermediate frequency (IF) signal at a fundamental frequency, the modulated IF signal also including a plurality of nth order components, a synchronous oscillator configured to receive the modulated IF signal, the synchronous oscillator also configured to operate at the fundamental frequency of the modulated IF signal, thereby providing an IF signal substantially free of the nth order components, and a translation loop having a phase locked loop, the translation loop configured to receive the IF signal output of the synchronous oscillator, and supply a radio frequency (RF) output signal to a power amplifier.

Abstract: In telecommunication devices like power amplifiers for cellular systems the amplitude of a transmission signal has to be limited to avoid signal deterioration. The improve the effciency of such amplitude limiter the present invention proposes to fed the input sample sequence to an estimation filter (56, 57) to determine the actual signal overshoot over a predefined threshold value. By this a clipping control signal to adjust the amplitude of the transmission signal accordingly can be generated with higher accuracy.

Abstract: A system is disclosed for transmitting and receiving signals. The system includes the use of a frequency plan table a system for creating the frequency plan table. The frequency plan table relates carrier frequency channels to the operation of a synthesizer and a plurality of programmable frequency dividers in a locked loop. In a transmitter, a first programmable frequency divider accepts a reference signal and produces a comparison signal. A mixer accepts the reference signal and a transmission signal and produces a loop signal. A second programmable frequency divider accepts the loop signal and produces a loop signal having a divided intermediate frequency signal. A phase detector compares the comparison signal and the loop signal having a divided intermediate frequency and produces an output that controls a variable controlled oscillator. The variable controlled oscillator produces a modulated transmission signal.

Abstract: A hybrid radio frequency transceiver using a single radio frequency transceiver able to send signals originating in at least two different frequency bands, wherein signals in a first frequency band are sent for transmission without conversion, and signals in all other frequency bands are converted to the first frequency band before being sent to the radio frequency transceiver. Also disclosed is a method for converting signals for a hybrid radio frequency transceiver using a single radio frequency transceiver able to send signals originating in at least two different frequency bands, wherein signals in a first frequency band are sent for transmission without conversion, and signals in all other frequency bands are converted to the first frequency band before being sent to the radio frequency transceiver.

Abstract: A method and telephone apparatus that places a telephone call to a directory assistance system and verbally provides the system with information identifying an entity is provided. The directory assistance system transmits data including at least the phone number and alphanumeric identifier of the entity to the telephone. Upon receipt of the data from the directory assistance system, the data is stored into the memory of the telephone. Thus, the telephone is automatically programmed with at least a telephone number and its associated alphanumeric identifier. Accordingly, the telephone number can later be recalled and dialed through the use of the alphanumeric identifiers.

Abstract: The invention provides an up/down converter with low phase noise. Signals from a first local oscillator are fed through a power splitter to first and second mixers. Signals from a second local oscillator and signals from the power splitter are mixed by the second mixer. The frequency component of the difference between the two signals is removed by a first bandpass filter and passed to a third mixer. Input signals are mixed with signals from the power splitter by the first mixer, and the lower frequency component of the output signals from the first mixer is removed by a second bandpass filter and is passed to the third mixer. Signals from the first and second bandpass filters are mixed by the third mixer. The higher frequency component of the output signals is removed by a low pass filter and is output.

Abstract: The invention provides an up/down converter with low phase noise. Signals from a first local oscillator are fed through a power splitter to first and second mixers. Signals from a second local oscillator and signals from the power splitter are mixed by the second mixer. The frequency component of the difference between the two signals is removed by a first bandpass filter and passed to a third mixer. Input signals are mixed with signals from the power splitter by the first mixer, and the lower frequency component of the output signals from the first mixer is removed by a second bandpass filter and is passed to the third mixer. Signals from the first and second bandpass filters are mixed by the third mixer. The higher frequency component of the output signals is removed by a low pass filter and is output.

Abstract: A two transistor mixer for mixing radio frequency signals in a communications device. A mixer core section comprised of a pair of matched semiconductor devices having their drain ports connected to a first common node through matched load resistors and their source ports connected to a second common node end. A local oscillator (LO) signal input connected to the first and second nodes, wherein the connection to the second node is through a current source. A radio frequency (RF) signal input connected to the gate ports of said pair of semiconductor devices and an intermediate frequency (IF) output obtained from the drain ports of said pair of semiconductor devices.

Abstract: Systems and methods are provided for calibration of a transmitter system modulator, wherein local oscillator nodes of a mixer are held at first and second voltages, and a first offset value is determined. The terminals are then held at third and fourth voltages and a second offset value is determined. The first and second offset values are then averaged to provide a calibration offset value for the modulator.

Abstract: A frequency modulating (FM) transmitter includes a reference frequency generator, a reference frequency divider, a stereo modulation circuit, an oscillator circuit, a program counter, and a PLL frequency synthesizer. The reference frequency generator is for generating a reference frequency. The reference frequency divider is for frequency dividing the reference frequency. The stereo modulation circuit is for frequency modulating audio signals by using one output of the reference frequency divider to supply resultant stereo modulated signals as FM signals. The oscillator circuit is for generating carrier waves to transmit the FM signals. The program counter is for frequency dividing the carrier waves into variable frequency components. The PLL frequency synthesizer has a phase comparator circuit for comparing the variable frequency components output from the program counter with another output of the reference frequency divider.

Abstract: A apparatus to provide a direct modulation transmitter having high dynamic range and low distortion using signal processing at a first frequency level for a signal to be transmitted and increasing frequency to transmission frequency in a manner to avoid distortion and utilizing a squaring function in up-converting basic processing signal.

Abstract: A transmitter for a wireless handset having a modified translation loop architecture. The transmitter includes a VCO that generates a modulated transmit signal having a frequency fTx, and a modulated signal source that generates a modulated LO signal with a frequency fLO. A mixer mixes the transmit signal with the LO signal to produce an IF signal having a frequency fIF. A first divider divides the LO signal frequency fLO by an integer M to generate a first comparison signal having a frequency fCF. A second divider divides the IF signal frequency fIF, after it is multiplied by an integer K, by an integer N to generate a second comparison signal having a frequency fCF.

Abstract: Methods and apparatus for bandpass filtering a radio frequency (RF) signal in a cellular transmit path to provide a filtered RF signal to a power amplifier. The methods comprise bandpass filtering the RF signal by tracking, without translating, the carrier frequency of the RF signal with a phase-locked loop prior to power amplifying the signal for transmission. The tracking filter provides symmetrical filtering by centering the pass band of the tracking filter on the RF carrier, irrespective of where the RF carrier is within the pass band of the system.

Abstract: Frequency modulation switching apparatus for rapidly increasing and decreasing the frequency within radio-frequency pulses of radio wave pulse trains transmitted by an antenna having series inductance and capacitance, the apparatus having, in combination, a solid state four-terminal rectifier bridge circuit with opposing pairs of bridge terminals connected with one pair of opposing terminals shunting said inductance and said capacitance; and series-connected staturable and linear inductors and an SCR switch connected between the other pair of opposing terminals of the bridge circuit, whereby the high-speed triggering of the SCR on effects corresponding high-speed frequency increasing or decreasing of the frequency within the radio-frequency pulse to provide the desired frequency modulation therein

Abstract: It is intended to provide a frequency multiplier capable of switching as appropriate among frequency signals having frequencies obtained by multiplying prescribed multiplication numbers with low current consumption and a simple circuit configuration in effectively utilizing frequencies in radio communication equipment. The base terminals of an input differential pair are biased by respective voltage sources, and an input frequency signal is input to one of the base terminals. The differential output terminals are connected to the base terminals of next-stage buffer circuit transistors, and their emitter terminals are connected to respective diodes. A full-wave-rectified signal, which is obtained at the connecting point of the cathode terminals of the diodes, is input to a comparison differential pair, which produces an output frequency signal by comparing the full-wave-rectified signal with a reference voltage.

Abstract: A system, method and computer program product are provided for managing content for output on a wireless device such as a personal digital assistant (PDA), a handheld computer, a wireless telephone, a device connected to a wireless modem, a pager, a standard telephone that transmits text-to-speech audio output, etc. Content selected for output on a wireless device is displayed on a management screen. The content is displayed substantially as it will be displayed on the wireless device. Organization and formatting of the content is allowed. A link to content can be created. Further, text can also be added for output on the wireless device. In another embodiment of the present invention, a method for managing content for output on a wireless device is provided. Content selected for output on a wireless device is aggregated in a habitat. The aggregated content is displayed on a management screen. Organization and formatting of the content is allowed. The creation of links to content is also allowed.

Abstract: A circuit configuration for direction modulation contains an oscillator, whose output signal is split into quadrature components for modulation with a useful signal. A frequency shifting circuit has the effect that that the output frequency and the frequency of the oscillator are fractional rational multiples with respect to one another. The circuit contains a phase shifter for generating first further quadrature components and also a divider for generating second further quadrature components. The quadrature components are mixed with one another. As a result of the frequency offset, the oscillation frequency of the oscillator is shifted to outside the useful frequency band. Remodulation effects do not influence the adjacent channels. The circuit can be realized simply and cost-effectively and, in particular, requires only one oscillator.

Abstract: An upconverter unit for a cable television system upconverts multiple channel signals from a common intermediate frequency to a VHF or UHF signal ready for transmission to subscribers. The two-stage upconverter provides a first stage in which different channel signals are upconverted to different frequencies which are spaced apart by same frequency difference characteristic of different channels in the cable system. A second stage of the upconverter uses a common oscillator signal to convert the various channel signals from the first stage to the frequencies at which they will be transmitted over the cable system.

Abstract: A transceiver for a portable radio communication apparatus comprising a receiver for receiving a signal at a received frequency and including a local oscillator, a transmitter being operable to transmit at a transmission frequency, said transmission frequency being offset from, and aligned to, the received frequency by a predetermined frequency spacing, the transmitter including a mixer having a first port for inputting said transmission frequency signal and a second port for inputting the local oscillator signal, and comprising means for rectifying the input local oscillator signal to provide a conductance waveform at a multiple of the local oscillator signal and means for mixing said transmission frequency signal with the conductance waveform at said multiple of the local oscillator signal frequency for down-converting the transmission frequency signal to an intermediate frequency signal.

Abstract: A radiocommunications terminal includes a send circuit and a receive circuit connected to a send/receive antenna of the terminal and respectively defining, when in operation, a send mode and a receive mode. The terminal also includes a circuit in a common part of the connection of the send and receive circuits to the antenna for matching the send and receive circuits to the antenna. A device for controlling and monitoring the power of signals sent/received by the terminal decenters the impedance matching of the antenna of the terminal only when the device is in send mode. Applications include reducing the energy impinging on the user of a mobile radiocommunications terminal.

Abstract: In an exemplary application, an apparatus according to a disclosed embodiment receives a radio frequency signal and outputs an intermediate frequency signal. Rejection of image components in the intermediate frequency signal is obtained without the need to preprocess the radio frequency signal with an image reject filter. Such an apparatus may also exhibit an image rejection performance that is robust to frequency deviation of a local oscillator.

Abstract: The invention relates to a method and arrangement for modulating a signal to be transmitted, the arrangement comprising an encoder and a frequency modulator. In order to enable high rate transmission in a flexible manner in a narrow frequency band, the encoder (104) is a differential encoder and before the frequency modulator, the arrangement comprises means for multiplying the signal to be transmitted by a factor of the form &pgr;/(2m), where m is a positive integer greater than one.

Abstract: A double balanced mixer for mixing an RF input signal with a local oscillator signal to provide at an output an intermediate frequency signal with high isolation over a wide frequency range. The mixer includes a local oscillator balun that is operable to receive a local oscillator signal. A RF balun that is operable to receive a RF signal. A first mixer has a first input port that is coupled to the local oscillator balun and a second input port that is coupled to the RF balun. The first mixer has an output port to provide an intermediate frequency signal. A second mixer is coupled in parallel with the first mixer. The second mixer has a first input port that is coupled to the local oscillator balun and a second input port that is coupled to the RF balun. The second mixer has an output port that provides an intermediate frequency signal. An intermediate frequency balun is coupled to the output ports of the first and second mixers.

Abstract: The output frequency of a frequency synthesizer (21) according to the present invention is a multiple of a transmission frequency and said output frequency is divided before modulation to produce the transmission frequency (fTX). In an advantageous embodiment, the frequency synthesizer produces a frequency that is twice the transmission frequency, which is divided by a divide-by-2 divider to produce 90°-phase-shifted transmission frequency components required by a transmission frequency quadrature modulator. A simple, disturbance-tolerant transmitter construction is achieved by means of the present invention.

Abstract: Interference effects between television transmitters for amplitude modulated or digital video and operating on a common allocated channel or frequency is avoided while discrimination is improved by synchronizing carrier signals for a plurality of transmitters. Booster transmitters for correcting coverage anomalies can operate of the same channel or frequency rather than requiring a different channel or frequency presently required in translators; making all allocable channels available for diverse broadcast programming. Discrimination between transmitters operating on the same channel or frequency but with potentially differing programming can be achieved with directional antennas. Synchronization of carrier signals is achieved by frequency multiplication of a tone relayed over a satellite transmission channel by an integral power of two using one or more serially connected full-wave rectifier stages and tuned filters.

Abstract: Interference effects between television transmitters for amplitude modulated or digital video and operating on a common allocated channel or frequency is avoided while discrimination is improved by synchronizing carrier signals for a plurality of transmitters. Booster transmitters for correcting coverage anomalies can operate of the same channel or frequency rather than requiring a different channel or frequency presently required in translators; making all allocable channels available for diverse broadcast programming. Discrimination between transmitters operating on the same channel or frequency but with potentially differing programming can be achieved with directional antennas. Synchronization of carrier signals is achieved by frequency multiplication of a tone relayed over a microwave transmission channel by an integral power of two using one or more serially connected full-wave rectifier stages and tuned filters.

Abstract: A method for generating a local oscillation signal comprising two separate frequency converters, of which one frequency converter includes an output unit for generating an internal output signal to be used for its frequency conversion, and the other frequency converter employs the same internal output signal from the output unit as the local oscillation signal.

Abstract: A frequency mixing system that provides an expanded dynamic range when compared to the dynamic range(s) of an individual mixer(s) that makes up the frequency mixing system. The frequency mixing system adjusts the amplitude of an input signal to be frequency mixed to produce a frequency converted signal with an acceptable and/or lower (when compared to the amplitude of intermodulation distortion produced by mixing the input signal without amplitude adjustment) amplitude of intermodulation distortion. If the input signal were frequency mixed without the amplitude adjustment, an unacceptable and/or higher level of intermodulation distortion would result (when compared to the corresponding intermodulation distortion if the amplitude-adjusted signal were mixed by an individual mixer). Adjusting the amplitude of the input signal creates an adjusted signal with signal distortion on the first path.

Abstract: A reception carrier wave, of which a frequency fL0 agrees with a frequency fRX of a reception wave, is generated, a first transmission carrier wave, of which a frequency fL1 is equivalent to twice of a difference value between the reception frequency and a frequency fTX of a transmission wave, is generated, and a second transmission carrier wave of which a frequency fL2 is equivalent to a difference value between the frequency fL0 and the frequency fL1, is generated. The reception carrier wave is mixed with the reception wave to produce a reception signal. The frequency of the first transmission carrier wave is halved, and the first transmission carrier wave is mixed with a transmission signal to produce a modulated wave. The second transmission carrier wave is mixed with the modulated wave to produce a transmission wave.

Abstract: The invention discloses an apparatus and method for reducing frequency pulling. Further, the invention provides amplitude modulation techniques to eliminate spurious signals and injection locking of the VCO to the output transmitted carrier. The architecture includes at least one synthesizer, a plurality of frequency dividers, an output VCO, a low pass filter, a mixer, a pretransmission filter and an amplifier connected in a manner to generate an output frequency which is non-harmonically related to the synthesizer VCO and to maintain the magnitude of the output frequency at, preferably, exactly 1.5 times higher than the VCO frequency.

Abstract: The present invention relates to a modulator comprising an oscillator which has an oscillation frequency, and a mixer intended to supply a modulated signal with a given output frequency. According to the invention, the nominal oscillation frequency is N times higher than the output frequency, the modulator further including a frequency divider DIV/N intended to receive the output signal of the oscillator and to apply the carrier signal to the mixer, to produce a modulated signal with a first modulation frequency and a parasitic signal with a second modulation frequency.

Abstract: A wireless microphone use UHF band carrier FM transmitter adopting a PLL system, which has a voltage controlled crystal oscillation type modulator (VCXO) for performing FM modulation on an oscillation frequency of a crystal oscillation circuit by an input of a modulation signal AF of an acoustic signal and which uses an FM modulated signal fr obtained from the VCXO as a reference signal Vr to be input to an analog phase comparator (PC) of a PLL circuit 60. The PC performs a phase comparison operation at a high speed (10 MHz or more), therefore a cutoff frequency of a loop filter (62) may be a high band frequency of about 100 KHz to 1 MHz so that the cutoff frequency considerably higher than the highest audible frequency 20 KHz can be selected. The filter output moves at an inaudible frequency and therefore there is no audible noise generated even due to vibration, feedback, etc.

Abstract: A dual band user terminal (10) includes a controller (18) for outputting a BAND signal for specifying operation in one of a first frequency band or a second, higher frequency band; a single frequency synthesizer (46) that is responsive to the BAND signal for outputting an RF signal in one of two frequency bands; and an RF transceiver (11) comprising a dual band receiver that receives RF signals in the first frequency band and in the second, higher frequency band, and a dual band transmitter that transmits RF signals in the same frequency bands.

Abstract: A transmit-receive system includes a phase-locked loop and a translation frequency loop. To bring about frequency hops, the frequencies in the two loops are varied with large increments in opposite directions. It is shown that the noise caused by the frequency division in the loops is thereby reduced.

Abstract: A wideband multiple channel frequency converter includes a mixer, a frequency generator for generating a local oscillator signal, a power divider for receiving the local oscillator signal and providing a portion of the signal to the mixer and a portion of the signal to a feed forward path which phase and amplitude adjusts the signal and a power combiner for receiving and combining a signal from the mixer and the phase and amplitude adjusted signal from the feed forward path. In addition, an attenuator may be implemented to reduce a power level of a signal to be converted and a band-pass filter may receive the signal from the power combiner. The converter compensates for local oscillator signal leakage and can reduce inter-modulation components.

Abstract: A frequency translation circuit (10) translates an incoming reference signal (RF.sub.IN) to a lower frequency using a compound mixer circuit (42). The compound mixer circuit (42) has a first mixer circuit (14A) that receives both the incoming reference signal (RF.sub.IN) and a signal generated by a first counter (28A). A second mixer circuit (14X) of the compound mixer circuit (42) receives a signal generated by a second counter (28X) and further translates the signal received from the first mixer circuit (14A) to a lower frequency. Both the first mixer circuit (14A) and the second mixer circuit (14X) generate output signals having a carrier frequency that is lower in frequency by the difference of the two input signals.

Abstract: A radio frequency synthesizer receives a relatively low frequency input signal and synthesizes from it a high frequency output signal whose frequency can be programmed to change in fine steps, for use e.g. in cordless telephone. The frequency synthesizer includes three linked phase locked loops with a single side band mixer in one embodiment coupling two of the phase locked loops together. This provides an output signal free of in-band frequency spurs within the spacing of two channels. The synthesizer can be integrated in a single chip with a narrowband FM modulation circuit. In spite of using a novel synthesizer to achieve monolithic integration, the user programming interface and control value equations are the industry standard format.

Abstract: Radio units responsive to a paging signal seize a trunk to connect wireless calls to telephone apparatus serviced by a private branch exchange. The radio units can each respond to a different set of mobile identification numbers, or can be configured in a master-slave arrangement or can employ subaddressing. Wireless trunking to a wireless private branch exchange can also be accomplished and a system with multiple hierarchical layers can also be formed.

Abstract: A single counter dual modulus frequency divider apparatus (400) utilizes a programmable divider (508) configured to receive an RF input signal at the divider system input (500) and a modulus control (516) produced by a programmable counter (510). The modulus control (516) sets a divide value of the programmable divider (508) to produce a divided signal at a programmable divider output (514). A switch (512) is configured to receive a first program instruction at the first program instruction input (504) and a second program instruction at a second program instruction input (506) to produce a count control (518). The programmable counter (510) receives the divided signal appearing at the programmable divider output (514) and the count control (518). The count control (518) sets the count value of the programmable counter (510).

Abstract: A radio communication device includes a transmission carrier generating circuit, a reception intermediate-frequency local signal generating circuit), a transmission radio-frequency local signal generating circuit and a reception radio-frequency local signal generating circuit, each of which is in the form of a frequency synthesizer. The radio communication device further includes a channel connection signal control circuit which cooperatively controls the transmission carrier generating circuit and the transmission radio-frequency local signal generating circuit and cooperatively controls the reception intermediate-frequency local signal generating circuit and the reception radio-frequency local signal generating circuit.

Abstract: A method and apparatus are provided for modulating a frequency synthesizer with an adjusted frequency control word determined by adjusting a carrier frequency control word based upon a bit content of a unsigned modulation control word. The method includes the steps of inverting a most significant bit of the unsigned modulation control word to produce an adjusted modulation control word and replicating the inverted most significant bit and appending the replicated bits to a most significant bit side of the adjusted modulation control word to increase a width of the adjusted modulation control word to a width of the carrier frequency control word. The method further includes the step of adjusting the carrier frequency control word by adding the replicated bits and the adjusted modulation control word to corresponding bits of the carrier frequency control word.

Abstract: A transmission and reception method and apparatus is capable of supplying local oscillation frequencies for upconversion and downconversion, as well as carrier frequencies for modulation and demodulation by utilizing only one local oscillator. The apparatus includes a reference signal generator for generating a reference signal, and a phase locked loop for locking the output of the reference signal generator to a predetermined frequency. A signal generator generates a signal in response to the output provided from the phase locked loop, and provides the signal to phase shifters in modulation and demodulation circuits. A first frequency multiplier multiplies the output of the signal generator, a first band pass filter band pass filters the output of the first frequency multiplier, and a first amplifier amplifies the output of the first band pass filter and provides the amplified result to an upconversion mixer.

Abstract: A phase-locked loop frequency synthesizer system is provided using fractional frequency division and a fractional control number for phase modulating an output of the frequency synthesizer using an incoming information signal. The apparatus includes a delta-sigma converter which adjusts a divisor of the frequency divider by operating upon a magnitude modulated fractional frequency control number. The system further includes a differentiator which provides the magnitude modulated input stream to the delta-sigma modulator by modulating the fractional control number with detected differences in the incoming information signal.

Abstract: In radio transmitting equipment that develops a carrier frequency using a mixer, techniques are used to "shift" or "hide" spurious mixer outputs so that they do not significantly degrade spectral purity of the transmitter output. These techniques generally involve establishing a predetermined frequency relationship between the two signals inputted to the transmitter mixer (TXIF (VCO) and TXLO) in addition to the relationship required to provide the desired difference frequency when the two signals are mixed in the mixer. By establishing a certain predetermined frequency relationship between these two signals it is possible to precisely locate the frequencies of the undesirable mixer output products so that they can be filtered out and/or fall onto the desired output frequency. While generally applicable, these techniques provide special advantages in equipment in which other considerations constrain the design of the transmitter circuitry and frequency inputs thereto.

Abstract: A first phase-locked loop (PLL) includes a first integrated voltage-controlled oscillator (VCO) whose output signal has a frequency modulated by an input signal of the device about a multiple of a reference frequency. A second PLL includes a second integrated VCO and frequency transposition means. The transposition circuit receive the output signal of the second VCO and a transposition signal having a non-modulated frequency. The second PLL addresses to the second VCO a control signal capable of aligning the frequency of the output signal of the transposition circuit with the frequency of the first VCO. The output signal of the second VCO forms the frequency modulation transmission signal produced by the device.

Abstract: A remote ground terminal for generating and transmitting a modulated data signal to a satellite. The remote ground terminal the remote ground terminal includes an indoor unit for generating a modulated data signal having an envelope of constant amplitude, and an outdoor unit including a transmitter module operative to receive the modulated data signal and to frequency multiply and amplify the modulated data signal so as to produce a modulated carrier signal having an envelope of constant amplitude. The transmitter module includes an active FET multiplier operative to frequency multiply the modulated data signal to the frequency of the modulated carrier signal, and a power amplifier operated in the saturation mode, which amplifies the modulated carrier signal to the desired power level. The components constituting the transmitter module are formed on a single integrated circuit.

Abstract: A selective call receiver (100) for receiving and transmitting paging signals has a transceiver (104) having an integer divide synthesizer (105) for achieving a fast lock time. The transceiver (104) has a reference oscillator (202) that generates a reference signal in a direct injection path and a modulator (206) coupled in the direct injection path modulates the reference signal to generate a modulated reference signal. A phase locked offset loop (220) coupled to the direct injection path generates a low frequency signal derived from the reference signal, a multiplier (210) coupled to the modulator (206) multiplies the modulated reference signal, and a mixer (214) coupled to the multiplier (210) receives the modulated reference signal in the direct injection path and an output signal from the phase locked offset loop (220) to generate a first local oscillator output signal and a modulated transmit carrier.

Abstract: A dual band transceiver for operating in a first lower frequency band such as the band allocated to cellular systems, and in a second higher frequency band such as the band allocated to personal communication services (PCS) systems. In a representative embodiment, the dual band transceiver comprises a main voltage controlled oscillator (VCO) for generating a local oscillator (LO) signal; an offset VCO for generating an offset frequency (OF) signal; a first mixer for combining the LO signal with the OF signal to produce a first transmit signal; a modulator for modulating the first transmit signal with the data signal to produce a first data modulated transmit signal; and a second mixer for combining the first data modulated transmit signal with the LO signal to produce a second data modulated signal. The main VCO and the offset VCO can be programmed such that the first data modulated transmit signal is in the first band and the second data modulated transmit signal is in the second band.

Abstract: A transmitter has an oscillator (101, 201, 303, 401, 501) that operates at frequency k multiplied by f.sub.c, thus the oscillator (101, 201, 303, 401, 501) outputs a signal at an output frequency, kf.sub.c. Coupled to the oscillator (101, 201, 303, 401, 501) is a frequency modifier (103, 205, 307, 405, 505), for modifying the oscillator output frequency by factor 1/k, thereby producing a signal at frequency f.sub.c at the frequency modifier output. Coupled to the frequency modifier output is a modulator (105, 215, 301, 407-417, 507-517) for producing a modulated output signal substantially centered at frequency f.sub.c.

Abstract: The invention relates to a general purpose circuit arrangement for a radio telephone wherein the universal application possibilities have been provided by phase-locked circuits (PLL1 to PLL3) and by a multiplier circuit (11, 12) that can be controlled (signals Select x1/x2 and Synte sel./Data) by the processor of the mobile telephone. The second harmonic or the fundamental frequency is selected by the multiplier circuit from the VCO oscillators (61, 62). In this way, the frequencies of the synthesizer circuits (UHF1, UHF2, UHF3) can be set independently of each other and according to the requirements of the respective cellular networks. The central circuits are advantageously integrated into four IC circuits (IC1 to IC4).