Abstract: According to an example embodiment, an apparatus is provided in a wireless transceiver. The apparatus may include a circuit configured to generate a first frequency signal (e.g., a VCO signal). A local oscillator (LO) generator may be provided that includes a frequency divider to divide the first frequency signal, and an image rejection mixer configured to mix the first frequency signal with an output of the frequency divider to generate an LO signal. In this manner, the LO generator may generate a desired LO signal while substantially rejecting or suppressing an unwanted sideband or image signal, according to an example embodiment.

Abstract: A radio circuit includes a mixing module, a first adjustable resonant circuit and a second adjustable resonant circuit. The mixing module is coupled to mix a first signal having a first carrier frequency with a second signal having a second carrier frequency to produce a mixed signal having a frequency sum component and a frequency difference component. The first adjustable resonant circuit is tuned to resonant at a frequency corresponding to one of the frequency sum component and the frequency difference component. The second adjustable resonant circuit is tuned to resonant at a frequency corresponding to another one of the frequency sum component and the frequency difference component, wherein the first and second adjustable resonant circuits alter the mixed signal to produce a converted signal.

Abstract: An RF transmitter (104) includes a shared local oscillator circuit (126), transmit path circuitry (120, 122, 124), a divider (134), and a lowpass filter (322). The shared local oscillator circuit (126) generates a shared LO signal (116). The transmit path circuitry (120, 122, 124) mixes a baseband signal (107) and an IF mixing signal (116) to provide an IF signal (112), and converts the IF signal (112) to an RF transmit signal (105) at a desired frequency using an RF mixing signal received at a mixing input thereof. The divider (134) divides the shared LO signal (116) to provide an unfiltered RF mixing signal. The lowpass filter (322) has an input for receiving the unfiltered RF mixing signal, and an output coupled to the mixing input of the transmit path circuitry (120, 122, 124) for providing the RF mixing signal.

Abstract: This invention relates to a system (100) for communicating wirelessly. The system (100) comprises an inductive antenna circuit (110) for transmitting and receiving inductively coupled signals, a driving means (102, 104) connected to inductive antenna circuit (110) and driving the inductive antenna circuit (102, 104) during a transmit mode, and comprises an amplifier means (112) connected to the inductive antenna circuit (110) and detecting and amplifying received signals differentially a receiving mode.

Abstract: An arrangement for generating a transmission clock signal and a reception clock signal is proposed in which only a single voltage-controlled oscillator is used, the reception clock signal being generated by phase-adjusting means whereas the transmission clock signal is generated directly by the voltage-controlled oscillator. Cross-talk between a plurality of voltage-controlled oscillators can be prevented in this way. Also, various measures are proposed for optimizing a circuit of this kind.

Abstract: A receiver is disclosed. The receiver includes: a tunable low noise amplifier (LNA), the tunable LNA comprising: a plurality of LNAs for receiving and amplifying a plurality of frequency bands respectively; a plurality of first switches respectively coupled to the plurality of LNAs; a plurality of LC loads, respectively coupled to the plurality of first switches; a plurality of buffers, respectively coupled to the plurality of first switches; and a plurality of second switches, respectively coupled to the plurality of LC loads and an LO signal; a power detecting circuit for determining a signal power level corresponding to the LO signal; a first switch unit; and a controller, for isolating the output of the plurality of LNAs, selectively decoupling at least one of the LC loads according to the signal power level of the LO signal, and routing the LO signal to the second switches during calibration mode.

Abstract: An embodiment of the present invention an apparatus, comprising an adaptive impedance matching module (AIMM) adapted to minimize the magnitude of an input reflection coefficient seen at an RFin port under boundary conditions of a variable load impedance ZL, a tuner connected to the AIMM and including a plurality of variable reactance networks with independent control signals, wherein node voltages are sampled within the tuner; and a microcontroller or digital signal processor (DSP) calculates complex reflection coefficient information from the sampled voltages, the microcontroller or DSP providing a coarse and fine tune function that feeds bias signals to control impedance matching.

Abstract: An apparatus, method, and system for voltage controlled oscillator band switching are described. A band switching apparatus may include a reference generation and comparison module, a clock pulse generation module, and a counter and gating module. The reference generation and comparison module may generate a positive signal based on a comparison of a loop filter voltage associated with a voltage controlled oscillator to a maximum tuning voltage and a minimum tuning voltage. The clock pulse generation module may generate a clock pulse in response to the positive signal. The counter and gating module may disable band switching of the voltage controlled oscillator when a lock condition is detected and the loop filter voltage is between the maximum tuning voltage and the minimum tuning voltage. Other embodiments are described and claimed.

Abstract: The present invention provides a filter unit cell. The filter unit cell includes a variable capacitor coupled in series between first and second nodes and an inductor coupled in series between the second node and a third node.

Abstract: Provided is a radio frequency transceiver. The radio frequency transceiver includes: a receiving unit for converting a radio frequency signal received by an antenna into an intermediate signal based on an intermediate local signal; a transmitting unit for converting an intermediate signal into a radio frequency signal based on a radio frequency local signal; and a local signal generating unit for generating the intermediate local signal and the radio frequency local signal.

Abstract: Systems, devices and methods are provided to switch between transmit and receive modes in wireless hearing aids. Various aspects of the present subject matter relate to a communication system. Various embodiments of the communication system include an antenna with a resonant circuit having an inductive coil connected to a tuning capacitor. The communication system includes means to selectively drive the resonant circuit during a transmit mode, and means to selectively receive an induced signal in the resonant circuit during a receive mode. The communication system further includes means to selectively include a frequency shift canceling component in the resonant circuit to provide a first resonance frequency in the resonant circuit in the transmit mode and a second resonance frequency in the resonant circuit in the receive mode such that the first resonance frequency and the second resonance frequency are approximately equal. Other aspects are provided herein.

Abstract: A communication device including a caller identification feature. Radio frequencies are associated with preferred calling numbers. When a telephone call is received from a preferred calling number, a radio is tuned to the associated frequency. When an SMS message or an MMS message is received, the radio is tuned to an associated frequency. The person receiving the telephone call or message may be able to identify the calling number by the particular radio station. Further, the invention is a method of indicating the telephone number of a calling telephone or receipt of an SMS message or MMS message by tuning a radio to an associated frequency. The invention also includes a storage medium having instructions which control a communication device to indicate a telephone number identifying a telephone from which a telephone call originated or to indicate receipt of an SMS or a MMS message.

Abstract: A monolithic radio integrated circuit includes a substrate, a set of one or more analog subcircuits on the substrate, a programmable bias current supply on the substrate coupled to the set to provide bias currents to the analog subcircuits of the set including programmable bias currents to one or more analog subcircuits forming a first subset of the set, and a digital subsection coupled to the programmable bias supply to determine the bias currents supplied to the analog subcircuits of the first subset, such that one or more characteristics of the radio integrated circuit are modifiable by programming the programmable bias supply.

Abstract: An apparatus and method for overcoming pilot pollution in a wireless communications network. The apparatus boosts a preferred pilot signal within a geographical area that is suffering from pilot pollution. The boosted pilot signal is stronger than the pollution in this area, and causes mobile stations to lock onto the boosted pilot signal rather than the pollution. A directional receiving antenna on the apparatus receives the preferred pilot signal from a selected base station. After amplifying the preferred pilot signal, the apparatus transmits the boosted pilot signal from an antenna within the geographical area. In this manner, mobile stations lock communicate with the selected base station when within the geographical area rather than the base station responsible for the pilot pollution. This may result in fewer dropped calls from the network and fewer inappropriate hand-offs.

Abstract: A ratiometric transmit path architecture for communication systems and related methods are disclosed. This ratiometric transmit path architecture utilizes a single local oscillator signal and dividers to provide mixing signals for intermediate frequency (IF) mixing circuitry and feedback mixing circuitry, thereby eliminating the need for separate IF and radio frequency (RF) voltage controlled oscillators (VCOs) in prior solutions.

Abstract: A device to transmit and receive data for remote control of hearing devices has a reduced size achieved by the transmitter coils of the transmitter and the receiver coil of the receiver being wound around a common, shared core. Moreover, a protective capacitor that is used to protect the receiver is at the same time used as a correction capacitor to correct the resonant frequency of a reception oscillator circuit.

Abstract: A method and apparatus for diversity switching control are generally described herein. According to one embodiment, a diversity control network is introduced which effectively reduces the number of coaxial cables required to interface with N antennas from the conventional N cables, to N/2 thereby providing significant cost saving.

Abstract: A base station and a method of configuring a base station are provided in a cellular telecommunication system, wherein the base station comprises an electrically tunable duplex filter with a tuning range covering at least two parallel sub-bands used in the telecommunication system. The electrically tunable duplex filter is tunable on site to a sub-band allocated to the base station, thus enabling an increased flexibility in selecting a fixed frequency band to be used in the lower frequency stages in the transceiver and the base band parts of the base station.

Abstract: A frequency synthesizer for use in a transceiver generates a relatively high reference frequency with fine frequency resolution and low in-band phase noise by using a digital processor to generate a digital reference signal at a finely-tuned reference frequency. A Digital-to-Analog Converter (DAC) converts the digital reference signal to an analog reference signal, and a low pass filter filters the analog reference signal to produce a filtered analog reference signal. The frequency synthesizer further includes a phase locked loop for up-converting the filtered analog reference signal from an IF signal to an RF signal.

Abstract: An entire radio transceiver can be completely integrated into one IC chip. In order to integrate the IF filters on the chip, a heterodyne architecture with a low IF is used. A single, directly modulated VCO is used for both up-conversion during transmission, and down-conversion during reception. Bond-wires are used as resonators in the oscillator tank for the VCO. A TDD scheme is used in the air interface to eliminate cross-talk or leakage. A Gaussian-shaped binary FSK modulation scheme is used to provide a number of other implementation advantages.

Abstract: A self-calibrating radio is described. In one exemplary implementation, a radio signal from its local voltage controlled oscillator. The calibration system automatically calibrates the radio by: (i) receiving a reference signal having a calibrated reference frequency, (ii) comparing the local frequency to the reference frequency to determine whether there is a difference between the local frequency and the reference frequency and (iii) adjusting the local frequency by an offset frequency, if the difference between the local frequency and the reference frequency is greater than a threshold value.

Abstract: A wireless audio transmission and reception system includes a pulse width amplifier, an up-converter, a transmitter, a receiver, a down-converter, an integrator, and a power amplifier to transfer an analog signal to a transducer such as a speaker. The pulse width amplifier receives an analog signal and modulates a pulse width of a timing signal with the analog signal. The pulse width of the timing signal is modulated such that the pulse width is proportional to the amplitude of the analog signal, and provides a pulse width modulated signal. The up-converter is in communication with the pulse width amplifier to receive the pulse width modulated signal and convert the pulse width modulated signal to a modulated carrier signal. The transmitter in communication with the up-converter to receive the modulated carrier signal and to transfer the modulated carrier signal wirelessly.

Abstract: The method and apparatus herein identifies tunable duplexer in a communication system. The tunable duplexer includes a tunable receiver filter, a tunable transmitter filter, a variable receiver phase shifter, and variable transmitter phase shifter. Each filter and phase shifter is optimized based on characteristics of impedance within the duplexer. The duplexer may be adjusted to changing environments or desired changes in the frequency of operation, reducing circuitry architecture and providing greater flexibility in communication function. The method commences by tuning tunable filters within the duplexer and then optimizing phase shifters within the duplexer for adjusting impedance matching with antenna and isolating the receiver from the transmitter during duplexing operations. Optimizations and calibration may be performed during manufacture, upon initialization of the system, or during operation of the communication device.

Abstract: A transmission level control method in a wireless local loop system capable of suppressing occurrence of an unnecessarily high transmission level, comprises a step of generating a required reception level corresponding to a classification of data, a step of detecting the reception level of data at a receiver side transceiver apparatus, a step of finding a level difference between the detected reception level and the required reception level corresponding to the classification of the related received data, and a step of controlling a change of the transmission level at a transmitter side transceiver apparatus according to this level difference.

Abstract: An entire radio transceiver can be completely integrated into one IC chip. In order to integrate the IF filters on the chip, a heterodyne architecture with a low IF is used. A single, directly modulated VCO is used for both up-conversion during transmission, and down-conversion during reception. Bond-wires are used as resonators in the oscillator tank for the VCO. A TDD scheme is used in the air interface to eliminate cross-talk or leakage. A Gaussian-shaped binary FSK modulation scheme is used to provide a number of other implementation advantages.

Abstract: In accordance with the present invention, a receiver circuit and a method of controlling voltage pulses, thereby improving the performance of the receiver are provided. The receiver circuit includes a switch for blocking high voltages and for converting voltage signals to current signals. The switch includes first and second signal terminals and a control terminal. The switch exhibits an ON resistance when closed, wherein the ON resistance is controlled by an electric value at the control terminal. The receiver circuit also includes a control circuit coupled to the switch for controlling the ON resistance of the switch in closed mode. The first switch signal terminal is coupled to an output of a transducer and the second switch signal terminal is coupled to an input of a low-noise amplifier circuit. The switch is a transmit/receive switch which is open during a transmission time interval and closed during a reception time interval.

Abstract: On-chip calibration signal generation circuitry is disclosed for filter tuning for radio-frequency communications and associated methods. On-chip circuitry generates a calibration signal that is used to help set a tuning control signal that is received by a tunable front-end filter. In one embodiment, local oscillator (LO) generation circuitry is used to generate the calibration signal. In operation of this embodiment, the LO generation circuitry is tuned to the desired receive channel, or to a frequency at some offset value from the desired receive channel, and the output of the LO generation circuitry is then used as a calibration input signal for a tunable front-end filter. This calibration signal is passed through the receive path circuitry, and the resulting signal is then analyzed to help set a tuning control signal for the tunable front-end filter.

Abstract: A monolithic radio integrated circuit includes a substrate, a set of one or more analog subcircuits on the substrate, a programmable bias current supply on the substrate coupled to the set to provide bias currents to the analog subcircuits of the set including programmable bias currents to one or more analog subcircuits forming a first subset of the set, and a digital subsection coupled to the programmable bias supply to determine the bias currents supplied to the analog subcircuits of the first subset, such that one or more characteristics of the radio integrated circuit are modifiable by programming the programmable bias supply.

Abstract: Methods to generate a mobile time reference are provided. A representative method includes providing a high frequency clock, providing a low frequency clock, generating a mobile time reference using the high frequency clock, maintaining the mobile time reference using the low frequency clock when the high frequency clock is turned off, and continuing to generate the mobile time reference using the high frequency clock when the high frequency clock has been turned back on. Systems and other methods are also provided.

Abstract: A transceiver having an RF receiver, in particular VHF receiver, with digital signal processing in a digital part. The transceiver having an input part, at least one mixer and an intermediate frequency/baseband processing device, having a local channel oscillator, to which a first phase locked loop with a phase discriminator and an adjustable first frequency converter are assigned, and having a reference oscillator for the phase locked loop and the control clock of the digital signal processing device, in which, in order to acquire the control clock, a digital clock synthesizer is provided to which an output signal of the reference oscillator is supplied, and a control signal is supplied by the digital part in the form of a digital tuning word, the frequency of the reference oscillator being selected such that its order of magnitude is at least equal to the bandwidth of one or more of the reception bands used, and none of its harmonics occur in a reception channel.

Abstract: An entire radio transceiver can be completely integrated into one IC chip. In order to integrate the IF filters on the chip, a heterodyne architecture with a low IF is used. A single, directly modulated VCO is used for both up-conversion during transmission, and down-conversion during reception. Bond-wires are used as resonators in the oscillator tank for the VCO. A TDD scheme is used in the air interface to eliminate cross-talk or leakage. A Gaussian-shaped binary FSK modulation scheme is used to provide a number of other implementation advantages.

Abstract: A RF transceiver for AMPS communication includes: a baseband processor for generating a transmission intermediate frequency signal and processing a reception intermediate frequency signal; a local oscillator for generating a local oscillation signal in transmission and reception; an up-mixer for combining the transmission intermediate frequency signal with the local frequency signal; a duplexer for processing a radio frequency signal received through an antenna; and a specific frequency removing unit installed between the local oscillator and an up-mixer to remove a specific frequency signal generated from the local oscillator. A filter is installed between the local oscillator and the up-mixer to remove the 2-times frequency of the local oscillation signal of 957.66 MHz, thereby removing the self-quieting phenomenon generated in the channel 76 of AMPS.

Abstract: A dual-band frequency converter unit, for selectively performing frequency conversion between a 2.4-GHz high-frequency-band signal or a 5-GHz high-frequency-band signal and a baseband signal by frequency mixing, includes a local oscillator for generating a local oscillation signal; a first frequency divider for generating a half-frequency signal of the local oscillation signal; and a second frequency divider for generating a quarter-frequency signal of the local oscillation signal. Frequency conversion between the 2.4-GHz high-frequency-band signal and the baseband signal is performed by frequency mixing using the half-frequency signal of the local oscillation signal. Frequency conversion between the 5-GHz high-frequency-band signal and the baseband signal is performed by frequency mixing using the local oscillation signal and the quarter-frequency signal of the local oscillation signal.

Abstract: A radio device requires a tunable transceiver such that the transceiver can be accurately set to a desired frequency. When a signal with known frequency accuracy is being received, an offset detector can determine the frequency offset generated by the transceiver due to improper tuning. An automatic frequency control (AFC) system (100) is comprised of a tunable transceiver, an adaptive detector (102) for comparing an incoming sample from the tunable transceiver to an adaptive maximum deviation threshold for determining if a sample from the tunable transceiver should be used for the direct current (DC) component of the AFC, an offset detector (103) and an AFC control processor (105) for utilizing information from the offset detector to reduce the inaccuracy in frequency by tuning the transceiver towards the received signal frequency. The AFC control processor (105) utilizes one of more threshold levels for defining a maximum correction threshold (311) based upon the desired maximum offset correction.

Abstract: The present invention provides a transceiver apparatus that permits miniaturization even when the antenna thereof is an unbalanced circuit and the transmitter circuit section and receiver circuit section thereof are balanced circuits. The transceiver apparatus is constituted comprising: a semiconductor integrated circuit device that mounts on the same semiconductor chip a balanced receiver circuit 41 for receiving a received signal as a differential input and balanced transmitter circuit 52 for outputting a transmitted signal as a differential output, and that has at least two terminals 71,72 connected to connecting nodes that connect the balanced receiver circuit 41 and the balanced transmitter circuit 52; first and second capacitors C2,C3 connected to the terminals 71, 72 respectively; an external inductor L1 connected to the first and second capacitors C2, C3; a band pass filter 2 and an antenna 1 coupled to the first capacitor C2; and a third capacitor C1 connected to the second capacitor C3.

Abstract: A digital radio stores advertisements for substitution during a broadcast for a bumpable advertisement within the broadcast. Upon detecting a bumpable advertisement within a predetermined broadcast period, the digital radio checks for higher priority stored advertisements—such as advertisements which were broadcast when the digital radio was not tuned to the station being monitored—and substitutes advertisements according to a priority scheme. Prioritization includes whether the advertisement has been played to the listener at least once during the broadcast period, and may extend to fee-based priority enhancements and tie-breakers or to selection based upon geographic location and/or direction of travel of a vehicle in which the digital radio is located.

Abstract: A method of communicating of the present invention includes broadcasting a signal from a transmission point. The power of the signal is limited such that the signal will attenuate within a predetermined distance from the transmission point. The signal is received by a receiver. A communication system includes a transmitter and a receiver. The transmitter is adapted to broadcast a first signal which attenuates within a predetermined distance from the transmitter. The receiver is adapted to receive the first signal. The method and system can be used to imperceptibly transmit voice data.

Abstract: An entire radio transceiver can be completely integrated into one IC chip. In order to integrate the IF filters on the chip, a heterodyne architecture with a low IF is used. A single, directly modulated VCO is used for both up-conversion during transmission, and down-conversion during reception. Bond-wires are used as resonators in the oscillator tank for the VCO. A TDD scheme is used in the air interface to eliminate cross-talk or leakage. A Gaussian-shaped binary FSK modulation scheme is used to provide a number of other implementation advantages.

Abstract: There is disclosed a system for tuning a tunable narrowband cavity filter in a base station transmitter of a wireless network. The radio frequency (RF) transmitter comprises: 1) modulation circuitry for modulating an input baseband signal to produce a first RF signal; 2) amplification circuitry for amplifying the first RF signal; 3) a tunable narrowband cavity filter for filtering the amplified first RF signal and transmitting the filtered and amplified first RF signal to an antenna coupled to an output of the tunable narrowband cavity filter; and 4) a system for tuning the tunable narrowband cavity filter.

Abstract: A radio device requires a tunable transceiver such that the transceiver can be accurately set to a desired frequency. When a signal with known frequency accuracy is being received, an offset detector can determine the frequency offset generated by the transceiver due to improper tuning. An automatic frequency control (AFC) system (100) is comprised of a tunable transceiver, an adaptive detector (102) for comparing an incoming sample from the tunable transceiver to an adaptive maximum deviation threshold for determining if a sample from the tunable transceiver should be used for the direct current (DC) component of the AFC, an offset detector (103) and an AFC control processor (105) for utilizing information from the offset detector to reduce the inaccuracy in frequency by tuning the transceiver towards the received signal frequency. The AFC control processor (105) utilizes one of more threshold levels for defining a maximum correction threshold (311) based upon the desired maximum offset correction.

Abstract: A system calibrates the gain of a repeater by determining a value based on the difference between respective amplitude measurements made while the repeater is transmitting and while it is not. The value is compared to threshold data in order to determine whether repeater attenuation should be incrementally adjusted.

Abstract: A tunable element in the microwave frequency range is described that may include one or more tunable elements that are directly digitally controlled by a digital bus connecting a digital control circuit to each controlled element. In particular, each digital signal is filtered by a digital isolation technique so that the signal reaches the tunable elements with very low noise. The low noise digital signals are then converted to analog control voltages. The direct D/A conversion is accomplished by a special D/A converter which is manufactured as an integral part of a substrate. This D/A converter in accordance with the invention may consist of a resistor ladder or a directly digitally controlled capacitor. The direct digitally controlled capacitor may be a cantilevered type capacitor having multiple separate electrodes or sub-plates representing binary bits that may be used to control the capacitor.

Abstract: An entire radio transceiver can be completely integrated into one IC chip. In order to integrate the IF filters on the chip, a heterodyne architecture with a low IF is used. A single, directly modulated VCO is used for both up-conversion during transmission, and down-conversion during reception. Bond-wires are used as resonators in the oscillator tank for the VCO. A TDD scheme is used in the air interface to eliminate cross-talk or leakage. A Gaussian-shaped binary FSK modulation scheme is used to provide a number of other implementation advantages.

Abstract: A quadrature tranceiver has a transmitter, a receiver, and a common local oscillator. With the transmitter switched off and the receiver switched on, a DC-error in the receiver is nulled in servo loops in in-phase and a quadrature receiver paths. After settling, the servo loops provide output values that are freed of the DC-error. DC-nulling output values are then sampled and stored. After sampling, the servo loops are opened. Thereafter, the transmitter is switched on while inputting a fixed signal to the transmitter, and DC-signals injected into in-phase and quadrature paths of the transmitter are adjusted until the opened servo loops provide the same output signal as obtained at the end of the DC-nulling. Corresponding values of the injected DC-signals are then stored as transmitter calibration values.

Abstract: In a PLL circuit, the number of LPFs is reduced to one to reduce mounting area and pin number, and to simplify design. In one embodiment, the PLL circuit includes a variable-gain phase comparator, a mixer, an LPF, VCOs, couplers, and a control circuit to controlling the on/off operation of the VCOs. The variable-gain phase comparator is capable of varying a phase difference gain. The on/off of the operation of the VCOs is controlled by the control circuit so that one of the VCOs is turned off. The phase difference conversion gain is varied in accordance with the sensitivity of the VCOs so the number of LPFs required for the PLL circuit can be reduced to only one.

Abstract: A differential two-or-more stage oscillator with precision phase tuning is presented. The phase difference between the stages can be varied by differentially adjusting the propagation delays of each stage. In addition, an injection-locked differential two-or-more stage oscillator with precision phase tuning is presented. The phase relationship between the stages can be altered without altering the frequency of the oscillator by differentially altering input bias voltages coupled to each stage. Additionally, a mechanism for the realization of a self-calibrating image-reject mixer architecture within a radio transceiver utilizing the new oscillator circuits is introduced. The mechanism provides a practical means for allowing a portable wireless device, for example, a cellular telephone, to calibrate its internal receive and transmit image-reject-mixer's phase and amplitude errors without the use of an externally applied test signal.

Abstract: A wireless terminal circuit includes a variable high frequency clock oscillator that provides a high frequency clock signal and a fixed low frequency clock oscillator that provides a low frequency clock signal. A phase-locked loop adjusts a ratio of the frequency of the high frequency clock signal to the low frequency clock signal by adjusting the frequency of the high frequency clock signal. The phase locked loop includes a divider for dividing the high frequency clock signal, the divide ratio of which divider is controlled by a sigma-delta modulator. A wireless terminal local oscillator calibration circuit includes a frequency control circuit including both the high frequency clock oscillator and the low frequency clock oscillator.

Abstract: An oscillator 10 includes temperature compensation circuits 30 and 40, a frequency adjusting circuit 50, and an initial deviation correcting circuit 60. Switches SW 1 to 4 are controlled based on control data DC stored in a memory 90 so that a temperature compensation voltage V1, a temperature compensation voltage V2, a frequency adjusting voltage V3, and an initial deviation correcting voltage V4, output from the above circuits, are selectively added, supplying a sum to a voltage-controlled oscillation circuit 20 as a control voltage VA.

Abstract: A radio-frequency (RF) apparatus includes front-end circuitry. The front-end circuitry includes a filter circuitry and an impedance matching circuitry. The filter circuitry has a differential output that has an output impedance. The filter circuitry filters signals outside a signal band of interest. The impedance matching network has a differential input coupled to the output of the filter circuitry. The impedance matching network also has a differential output coupled to a signal processing circuitry. The signal processing circuitry has an input impedance. The impedance matching network matches the input impedance of the signal processing circuitry to the output impedance of the filter circuitry.

Abstract: An apparatus for synchronising the system clocks of wireless devices in a digital communications system is presented. A digital phase-locked loop is employed. The phase-locked loop may include a counter which is incremented by a local device system clock and latched by a frame synchronisation marker received from a remote device, whereby the counter output comprises a feed forward signal. The phase-locked loop may alternatively include a counter that reflects the level of data stored in receive and/or transmit FIFO buffers. The loop output signal controls the frequency of the system clock oscillator.