Abstract: A front end tuning system includes a tuning signal generator. The tuning signal generator includes a digital-to-analog converter (DAC) to receive a pre-conditioned tuning signal at a reference input, to receive a digital value at a digital control input, and to produce a modified tuning signal based on the digital value and the pre-conditioned signal. Preconditioning the tuning-voltage allows a simple current type DAC to be can be used, rather than an 8-bit ladder type DAC used by some other front end tuners. Significant cost savings can be achieved because less memory is required to store the digital values supplied to the DACs, and set up times can be reduced. An adjustable temperature compensation circuit provides additional adaptability.

Abstract: A telecommunication system uses a satellite antenna showing on the horizontal plane, a sufficiently narrow radiation lobe to discriminate two adjacent satellites and showing on the vertical plane, a sufficiently narrow vertical lobe to ensure an adequate gain, but sufficiently ample to enable the reception of a certain number of satellites in adjacent orbital positions, by land stations distributed over a certain meridian arc without the necessity for antenna elevation angle variations.

Abstract: An impedance matching circuit (140) includes a capacitive element (C1, 220), having a capacitance C, coupled in parallel with an output node (215) of the matching circuit, and an inductor (L1, 225) coupled in series with a transmission line (T1, 230) between the input node and the output node. The transmission line has a length that, in combination with the inductor, provides impedance substantially equal to the input impedance of the transmission circuit (150) at a frequency of interest. In one embodiment, the inductor is connected to an output (195) of an amplifier (180), and the transmission line is connected to the inductor and to the output (215). The capacitive element is connected to the transmission line such that the length of the transmission line between the inductor and the capacitive element provides the desired inductance.

Abstract: The present invention provides a serrodyne architecture that is capable of operating at high frequencies. The architecture generally includes a coupler, a delay line, and a switching system. The delay line is coupled to a reflective port of the coupler. The switching system is coupled to the delay line at different points and is configured to selectively shunt those points on the delay line to change the effective electrical length of the delay line. The effective electrical length is changed throughout the period, corresponding to the amount the frequency of the input signal is shifted. In operation, an input signal is provided to an input port of the coupler, and an output signal is provided at the output port, wherein the input signal and the output signal vary by a translation frequency, which is controlled based on how the effective electrical length of the delay line is changed.

Abstract: A receiver includes an antenna, an impedance-matching circuit, a receive circuit, a control circuit, a digital-to-analog (D/A) converter, a mode switch, and an EEPROM. The impedance-matching circuit includes a variable-capacitance diode. The control circuit determines an operation mode set by the mode switch. It controls the D/A converter to produce different levels of the reverse bias voltage when the operation mode is set to an adjustment mode. It determines strength of receive signals based on receive signal strength indication (RSSI) signals indicating strength of the receive signals. It determines a maximum value of the RSSI signals based on the results of the determination, and stores D/A input data corresponding to the maximum value in the EEPROM as the adjustment data. It loads the adjustment data from the EEPROM and controls the D/A converter to produce a reverse bias voltage based on the adjustment data. The D/A converter applies the voltage to the variable-capacitance diode.

Abstract: A multi-band receiver in which characteristics including a tracking error are improved is provided with a variable frequency oscillator circuit, a variable divider circuit (39) for dividing an oscillation signal (SVCO) of the variable frequency oscillator circuit, and mixer circuits (15I) and (15Q) for subjecting a received signal SRX to frequency conversion into an intermediate frequency signal (SIF) by a local oscillation signal (SLO). A divided output of the variable divider circuit (39) is supplied as the local oscillation signal (SLO) to each of the mixer circuits (15I) and (15Q). When a signal in a first frequency band is received, the division ratio n of the variable divider circuit (39) and the oscillation frequency of the variable frequency oscillator are changed to change the reception frequency in the first frequency band.

Abstract: A demultiplexer includes an antenna terminal, a reception filter connected to the antenna terminal, a transmission filter connected in parallel to the reception filter with respect to the antenna terminal and having a pass band center frequency that is different from the reception filter, a common inductance component connected between the ground terminal of the transmission filter and the ground terminal of the reception filter, and inductance components, which are different from the common inductance component, provided between the common inductance component and the reception filter and between the common inductance component and the transmission filter.

Abstract: A matching unit includes a switching means for switching an inductance of a first inductor. This switching means sets an inductance such that a first inductor shows an inductance property to both of the VHF low-band and high-band, and shows a capacitance property to the UHF band. This structure allows the matching unit to achieve the matching for both the VHF low-band and high-band by just switching the two circuits of the VHF low-band and high-band, also allows the matching unit to show a capacitance property to the UHF band. Thus the loss produced in transmitting signals can be reduced, and the circuit can be simplified. As a result, the matching unit can be downsized, and the cost can be reduced.

Abstract: The disclosed embodiments relate to a system and method for providing user specific beams in a fixed beam network, the fixed beam network comprising a plurality of fixed beams, each of the plurality of fixed beams being defined by a plurality of fixed beam correlation coefficients. The system may comprise a device that computes reception correlation data for a received signal, and a beamformer that is adapted to determine transmission weighting coefficients to be applied to a return signal based on the difference between the reception correlation data and the fixed beam weighting coefficients associated with at least one of the plurality of fixed beams.

Abstract: Electronic circuitry supports utilization of a series of pulses of varying width to tune a transducer (e.g., a coil that produces or receives a magnetic field) for transmitting or receiving. For example, a control voltage generator generates a sequence of digital pulses of varying pulse widths to produce respective control voltages. The control voltage generator applies a produced control voltage to a varactor element whose capacitance changes depending on a magnitude of the produced control voltage. The varactor element forms part of a tank circuit. Consequently, the series of pulse widths controls an operating frequency of the tank circuit at different times. The tank circuit includes an inductive coil that is tuned to produce or receive a magnetic or inductive field.

Abstract: A transmission system or apparatus includes a transmitter or source of transmitted RF or microwave power which is selectively connectable via a transmitter connector to an antenna having an antenna feed via an antenna connector so that a variety of antennas with differing characteristics can be used with a given transmitter. Each antenna preferably has a marker or indicating element incorporated into the antenna feed. The marker or indicating element includes a physically measurable property or parameter corresponding to a physical characteristic of the attached antenna. In the preferred embodiment, the indicating element is a resistance connected in parallel with the antenna feed and having a selected resistance value (e.g., in ohms) which indicates the physical characteristic of gain for antenna. The transmission system also includes an indicating element sensor configured to sense or measure the marker or indicating element and generate a transmitter control signal in response to that measurement.

Abstract: A telecommunications device is provided that enables monitoring of the directivity of a wireless communications system that wirelessly transmits signals using multiple communications antennas while controlling the overall directivity of the multiple antennas. At least one monitor antenna, installed separately from multiple communications antennas controlled to achieve a prescribed overall directivity, wirelessly receives signals from the multiple communications antennas. A directivity information acquisition mechanism uses the signals received by the monitor antenna to acquire information regarding the overall directivity of the multiple communications antennas.

Abstract: A trainable transceiver for learning and transmitting an activation signal that includes an RF carrier frequency modulated with a code for remotely actuating a device, such as a garage door opener. The trainable transceiver preferably includes a controller, a signal generator, and a dynamically tunable antenna having a variable impedance that may be selectively controlled in accordance with a detector circuit signal. The detector circuit provides a measurement of the transmission power and is also used to vary the applied transmission power of the transceiver in response to operating and environmental parameters.

Abstract: A tuner receiving system, a control unit for controlling a tuner receiving operation, a computer readable storage medium, and a method of receiving radio waves by using a tuner, are disclosed. The tuner receiving system outputs video and audio signals by processing the signals sent out when communication is established between a tuner unit for receiving radio waves from external sources and a capture card or the like. The main part of the system or the control unit discriminates the type of the tuner included in the tuner unit, based on a control signal output from the tuner unit after the start of the communication between the tuner unit and the communication interface unit, and displays a receiving station corresponding to a channel receivable by the tuner, in accordance with the type of the tuner and information from the communication interface unit.

Abstract: An antenna assembly has an antenna set, a rotation assembly and a control circuit for driving the rotation assembly to rotate to adjust receiving angel of the antenna set. The control circuit can learn to adjust remote signals represented different channel number on a remote control to automatically control the receiving angle and direction of an antenna set. Thus, the antenna assembly can be suitable to general remote control to automatically adjust the antenna set to search the wireless bands. Besides, the control circuit further stores data related to the wireless bands with the corresponding channel number to be easy for user turn to specific wireless band without searching step.

Abstract: An apparatus and method is related to a wireless system with an antenna that is automatically tuned to a desired frequency. The antenna is coupled to an adjustable tuning circuit to form a tuned antenna circuit that has a resonant frequency. The adjustable tuning circuit may be adjusted by activating a sweep generator that varies a tuning element over a broad frequency range. The sweep of the sweep generator is terminated after the proper frequency is found. Alternatively, the adjustable tuning circuit may be adjusted using an array of switched capacitors using a successive approximation method. The tuned antenna circuit may be employed to receive and/or transmit information. The resonant frequency is dynamically shifted in response to a data signal such that the antenna transmits FSK encoded signals.

Abstract: The present invention provides systems and methods for addressing the effects of non-linear phase response, such as by equalizing electrical delays among transmission paths. A preferred embodiment provides phase detection circuitry and phase adjustment circuitry in the signal paths of a multiple beam or phased array antenna to provide delay equalization of the signal paths. Communication systems implementing the systems and methods of the present invention are provided broadband phase calibration and, therefore, are enabled to provide controlled and predictable beam forming over a broad range of frequencies.

Abstract: The invention is to set a resonance frequency to various resonance frequencies by cutting a signal line which connects a tuning capacitor for trimming and an antenna currently with a milling step making a hole for mounting an IC module.

Abstract: A device for matching an antenna impedance in a portable radio telephone having transmission and receiving circuits, a foldable casing enclosing the radio, the foldable casing movable between an unfolded position and a folded position, an antenna movable between an extracted position from the foldable casing and a retracted position into the foldable casing includes means for sensing whether the foldable casing is in the unfolded position and for sensing whether the antenna is in the extracted position, and for providing a sensing signal in response thereto, and means for matching an impedance of the antenna and an impedance of the radio in response to the sensing signal, thereby making an optimal matching of impedances between the antenna and the radio according to the states of the folder casings and the antenna, and according to the transmission/reception mode.

Abstract: A high frequency circuit board comprising: a choke coil circuit element of a high frequency switching circuit; a dielectric laminated structure body comprising a plurality of dielectric layers which comprise a first dielectric layer and a second dielectric layer; a land formed on the first dielectric layer; and a circuit pattern formed on the second dielectric layer, wherein the choke coil circuit element is mounted on the land as a chip inductor, the first dielectric layer is located at the end of the body, the second dielectric layer is located nearest to the first board in at least one of the dielectric layers on which a circuit pattern is formed, and the land is positioned out of a region formed by projecting the circuit pattern formed on the second dielectric layer in the direction of laminating of the plurality of dielectric layers.

Abstract: A method and device for achieving space diversity reception in a system that has a first antenna and a second antenna disposed apart from each other over a quarter wavelength of the operating frequency, wherein the first antenna is optimally tuned to a first frequency for receiving signals in an operating mode. In its first function, the second antenna is optimally tuned to a second frequency for transmitting signals in the same mode or for receiving signals in a different mode. In its second function, the second antenna can be tuned to the first frequency so that it also receives signals in the first frequency in the same mode as the first antenna. The signals in the first frequency received by the second antenna are combined with the signals received by the first antenna.

Abstract: A ferro-electric tunable duplexer is provided, integrated with one or more of the following parts: a power amplifier, an isolator, a diplexer, a low noise amplifier and an antenna matching circuit. More specifically, in addition to adding F-E tunability, one or more of the above components is integrated with the duplexer on one substrate. The components are integrated on one substrate either by placing each component, with the appropriate matching circuit directly on the substrate, or by direct fabrication of the component and matching circuit into or onto the substrate.

Abstract: A high-frequency module constituted by an integral laminate for handling a plurality of transmitting/receiving systems having different passbands comprises (a) a switch module part for branching higher-frequency signals and lower-frequency signals and switching connection to the transmitting systems and the receiving systems, (b) a high-frequency amplifying circuit module part, and (c) a phase-adjusting circuit disposed between the switch module part and the high-frequency amplifying circuit module part, wherein the phase matching between the switch module part and the high-frequency amplifying circuit module part via the phase-adjusting circuit is adjusted to conjugate matching in a fundamental frequency band, while it is adjusted in a nonconjugate matching range in n-th frequency bands, wherein n is an integer of 2 or more.

Abstract: A front end tuning system includes a tuning signal generator. The tuning signal generator includes a digital-to-analog converter (DAC) to receive a pre-conditioned tuning signal at a reference input, to receive a digital value at a digital control input, and to produce a modified tuning signal based on the digital value and the pre-conditioned signal. Preconditioning the tuning-voltage allows a simple current type DAC to be can be used, rather than an 8-bit ladder type DAC used by some other front end tuners. Significant cost savings can be achieved because less memory is required to store the digital values supplied to the DACs, and set up times can be reduced. An adjustable temperature compensation circuit provides additional adaptability.

Abstract: A high-frequency device includes an antenna terminal, a signal line connected to the antenna terminal, a high-frequency signal processing circuit connected to the signal line, a capacitance element having one end connected to the signal line and other end grounded, and an inductor having one end connected to the signal line and other end grounded. The high-frequency device can protect the high-frequency signal processing circuit from a high voltage noise, such as a static electricity, having a frequency close to a signal pass band.

Abstract: The invention relates to a tuner with at least a first and a second frequency band and with means for effecting a switch-over between the frequency bands, which tuner comprises a signal input terminal for the supply of a frequency information signal. The invention is characterized in that the tuner comprises a band selection circuit which is provided for the selection and control of one frequency band at a time, and in that the tuner comprises a frequency search function for tuning to a frequency, which function in a first step is designed to test the tuning possibility of the frequency in the first frequency band and, if tuning in the first frequency band is not possible, in a second step is designed for testing the tuning possibility of the frequency in the second frequency band.

Abstract: A broadcast radio frequency receiver includes an improved seek circuit receiving analog radio signals via an antenna according to a signal seek process wherein the frequency of the analog radio signals sequentially changes. In one embodiment, an analog-to-digital (A/D) converter converts the magnitudes of the incoming radio signals to digital signal values (DV), and in an alternate embodiment a tuning circuit provides the digital signal values (DV) directly. In either case, a digital control circuit compares the digital signal values (DV) with a digital reference value (DRV), wherein DRV has a value corresponding to an analog signal reference level appropriate for the type of antenna being used. As long as the digital signal values are less than DRV, the seek process continues. Upon detection of a digital signal value in excess of DRV, the seek process is halted and the tuning circuit is allowed to maintain tuning to the current radio signal.

Abstract: An antenna assembly has an antenna set, a rotation assembly and a control circuit for driving the rotation assembly to rotate to adjust receiving angel of the antenna set. The control circuit can learn to adjust remote signals represented different channel number on a remote control to automatically control the receiving angle and direction of an antenna set. Thus, the antenna assembly can be suitable to general remote control to automatically adjust the antenna set to search the wireless bands. Besides, the control circuit further stores data related to the wireless bands with the corresponding channel number to be easy for user turn to specific wireless band without searching step.

Abstract: A wireless speaker apparatus for a radio communication device includes a receiver front end to receive two RF carrier signals with audio information. A tunable filter circuit provides a low side and high side frequency response slope to slope demodulate the carrier frequencies to provide respective amplitude modulated output signals. A control signal tunes a center frequency of the tunable filter circuit to center one of the low or high side frequency response slopes near its associated carrier frequency while decentering the other frequency response slope from its carrier frequency so as to favor demodulation of the former modulated output signals over the latter. An audio back end converts the amplitude modulated output signals to audio. This same simple apparatus can be used for either left or right channel audio signals depending on the control signal.

Abstract: A shortwave radio-receiver shows an improved reception sensitivity that can be used in a highly convenient way. The receiver is adapted for the superheterodyne system and the PLL synthesizer system and includes a front end circuit 33A for converting the received shortwave signal into an intermediate frequency signal. It also includes a formation circuit 50 for forming a tuning voltage VMB to be applied to the variable capacity diode of the antenna module and a jack J32. When the antenna module is in use, the formation circuit 50 is controlled in response to the reception frequency of the front end circuit 33A so as to modify the tuning voltage VMB and make the latter correspond to the reception band of the received shortwave broadcast to be received. The tuning voltage VMB is applied from the jack J32 to the variable capacity diode and, at the same time, the received signal is fed to the front end circuit 33A.

Abstract: An automatic radio frequency signal switching circuit is equipped with a plurality of AV input terminals and adopts an analog/digital adapter to transform all respective input analog signals into high level digital signals and a central processor is used to memorize the sequential orders of the respective AV signals which are sequentially output in a last-in-first-out manner to a television. At the same time, the central processor shuts off the ANT/CATV signal amplifier and the RF switch thereof so as to effect automatic switching operation. When no AV signals from AV equipment are being input, the central processor will instantly transmit another set of high electric level signals to the ANT/CATV signal amplifier and a power source of the RF switch thereof and the ANT/CATV signals are delivered to a television via the RF amplifier and the RF switch thereof whereby effect automatic RF switching operation.

Abstract: A tuning circuit, as for a television receiver or video recorder, employs switchable tuning circuits including micro-electronic electro-mechanical switches for selecting the ones of an array of capacitors and/or inductors as is useful in tunable circuits. The array of capacitors and/or inductors and micro-electro-mechanical switches of the switched tuning matrix is formed on an integrated circuit or an electronic circuit substrate along with amplifiers and other electronic elements of the tuning circuit for which the switched tuning matrix is employed. The switchable capacitance and inductance matrices are well suited for use in the resonators employed in the pre-selector filters, post-selector filters and oscillators of electronic tuners, such as those employed in television receivers and video recorders.

Abstract: There is provided an antenna impedance adjuster including (a) an antenna through which radio signals are received and transmitted, (b) a radio signal receiver which receives radio signals having been received through the antenna, (c) a radio signal transmitter which transmits radio signals through the antenna, (d) an adjuster which matches an impedance between the antenna and the radio signal receiver in radio signal receiving band and an impedance between the antenna and the radio signal transmitter in radio signal transmitting band, (e) a first switch which electrically connects the adjuster to one of the radio signal receiver and the radio signal transmitter, and (f) a controller which controls an operation of the first switch when a radio signal is received or transmitted.

Abstract: A set top box is provided with a patch antenna to wirelessly communicate with other devices. In one embodiment, the set top box has a metallic enclosure with a non-metallic bezel covering the front of the device. A communication circuit board with an imprinted patch antenna is located in the interstitial space between the metallic enclosure and the non-metallic bezel. The communications board preferably comprises a thin (0.06 inch) FR-4 circuit board with etched copper cladding. The patch antenna preferably comprises a ground plane on one side of the circuit board, and a rectangular patch on the opposite side of the circuit board. The patch is side-fed by a microstrip feed. The dimensions of the antenna are selected to optimize the antennas performance in frequency range between 2.400 and 2.483 GHz when located in the above-described interstitial space.

Abstract: A novel wireless handset is provided which can provide control so as to tune a center frequency of impedance matching of a tunable antenna to a call frequency. A first control signal sent from the central processing unit 51 to the synthesizer 41 or data used in the central processing unit to generate the first control signal is used to generate a second control signal by the central processing unit or the control signal generator 52 provided in the outside connected with the central processing unit, and the second control signal is applied to the control circuit 30 for center frequency of impedance matching, whereby center frequencies of impedance matching of the tunable antenna 10 are controlled.

Abstract: An antenna circuit which is improved the deterioration of amplitude characteristic in a strong electric field, an antenna circuit for AM broadcasting which can surely inhibit and damp FM-band signals in the strong electric field and amplifies to output AM-band signals, and an antenna circuit for AM/FM broadcasting in which AM-band signals are not damped by means of an FM-band filter. In the first antenna circuit, the output signal of an antenna (10) is supplied to the base of a transistor Tr2 forming a current amplification type amplifier having a high-input and low-output impedance and the emitter of the transistor Tr2 is grounded through a coil L6 and connected to an FM receiver (16) through a band-pass filter (38). In the second antenna circuit for receiving AM broadcasting, an input terminal is connected to an AM amplifier circuit (36) through coils (L7) and L8 in series and to the gate G of a field effect transistor FET.

Abstract: A radio device includes a receiving part (45) formed by a high-frequency selective amplifier stage (50) including a frequency selective circuit (51) having a plurality of capacitive elements (68-78), any one or more which can be selectively connected into the selective circuit in dependence on a control magnitude stored in a storage element (90) in order to tune the selective circuit to a certain frequency. Under the control of a microprocessor (92) the stored control magnitude is set to that which gives the best level measured by a level detector (98) at the output of the amplifier stage. The microprocessor varies the control magnitude to produce a series of alternate connections into the selective circuit of each and every combination of one or more of the reactive elements, receives the measurement by the level detector of the level at the output of the amplifier stage or each control magnitude, and selects the control magnitude giving the best level.

Abstract: The direction-of arrival estimation by means of a subspace-based algorithm such as MUSIC or ESPRIT is formed by using reduced-bandwidth signals as compared with communication signal waves. The narrower-bandwidth signals is obtained by each mobile telephone transmitting a modulated version of a lower-transmission rate test signal as well as a communication signal wave or by band-pass filtering the received communication signal waves in a base station. A direction-of-arrival estimation is formed by using a reduced number of signals for the direction-of arrival estimation. The number of direction-of-arrival estimating signals is reduced by discarding a part of the received signals, by multiplexing the received signals by the sub-array and forming a direction-of arrival estimation for each sub-array, or by using an additional array antenna having a reduced number of elements.

Abstract: A reception control system for automobiles according to the present invention includes tuners for a plurality of receivers for receiving various types of waves including at least an AM/FM broadcast wave, a TV broadcast wave and a GPS wave. The tuners are separated from receiver bodies and integrally incorporated into an antenna section (a plurality of antenna elements+an AM/FM reception circuit+a TV reception circuit) including at least a plurality of antenna elements. The tuners are supplied with a digital control signal through a LAN provided in an automobile thereby to control reception of waves.

Abstract: A wireless terminal has an antenna arrangement including one or more antennas (102a, 102b) designed to reduce substantially currents flowing on ground conductors (104a, 104b, 104c) within the device. In known terminals, these currents generate radiation of unwanted polarisations and radiation in unwanted directions, and can also reduce radiation efficiency.

Abstract: A tuner receiving system, a control unit for controlling a tuner receiving operation, a computer readable storage medium, and a method of receiving radio waves by using a tuner, are disclosed. The tuner receiving system outputs video and audio signals by processing the signals sent out when communication is established between a tuner unit for receiving radio waves from external sources and a capture card or the like. The main part of the system or the control unit discriminates the type of the tuner included in the tuner unit, based on a control signal output from the tuner unit after the start of the communication between the tuner unit and the communication interface unit, and displays a receiving station corresponding to a channel receivable by the tuner, in accordance with the type of the tuner and information from the communication interface unit.

Abstract: Ordinarily, at least two types of mixer oscillator integrated circuits for tuners have to be used, i.e., one for the symmetrical output mode and one for the asymmetrical output mode. In order to handle both output modes, a tuner includes a switching circuit, whereby, in the asymmetrical mode, one output of the tuner is coupled to ground.

Abstract: Upon installation of a broadcast receiver, for example, a television receiver, the different tuning frequencies/channel numbers are to be stored in a memory of the broadcast receiver. To facilitate the installation, the network provider transmits a list of nominal tuning frequencies, for example, as a teletext page, together with at least one of the broadcast television programs. To further improve installation, also the RF frequency of a so-called subscription channel is also inserted in the list. As the RF frequency of the set-top box may differ from the nominal value in the list, a fine-tuning is performed to modify the stored tuning frequency/frequencies.

Abstract: A method and a system for tuning a resonance module in e.g. a radio base station are disclosed. The resonance module has tuning means, a transmitter connection, and an antenna connection. First frequency input and output signals on the transmitter and antenna connection, respectively, are sensed and processed to tune the resonance module to a frequency of the input signal on the transmitter connection. The processing of the sensed input and output signals includes processing in a second frequency range. Prior art methods are improved by the invention through e.g. the use of a quadrature modulator to increase adjustment speed and overall applicability of the resonance module to be tuned.

Abstract: In order to select one or more microwave signals from among the signals which it receives, the reception device comprises switching circuits. The switching circuits are commanded by command signals. According to the invention, a switching circuit command signal consists of at least two sinusoidal signals generated according to the principle of voice-frequency dialling. The invention applies more particularly to the reception of signals from telecommunication and/or telebroadcast satellites.

Abstract: An antenna tuning circuit 1 is tuned to a received RF signal, and outputs a signal into an RF amplifying circuit 2 for amplification. After amplification, the circuit 2 outputs a signal to an RF tuning circuit 3, which is then tuned to the supplied signal. Since the frequency of a local oscillation signal is set according to the frequency of an object station, the RF signal of an object station is converted by a mixing circuit 4 into an IF signal having a predetermined center frequency. Also, the tuning frequency of the antenna tuning circuit 1 is adjusted to match the frequency of an object station. When disturbance stations with strong field intensity are received, field intensity of a received signal exceeds a predetermined level and a dumping control circuit 9 is activated to generate a dumping signal. In response to the dumping signal, a dumping circuit 10 is turned on, as a result of which an output signal of the antenna tuning circuit 1 is attenuated.

Abstract: An FM radio receiver comprises a radio frequency tuning circuit for selecting a frequency modulated signal from an antenna and a local oscillator tuning circuit for tuning to an oscillating signal so as to convert the frequency modulated signal to an intermediate frequency. In the radio frequency tuning circuit, a capacitance variable ratio is set so as to be capable of receiving continuously the frequencies of both a first FM receiving band used in Japan and a second FM receiving band used in the US and Europe. The local oscillator tuning circuit is so constructed that an inductance value and a capacitance variable ratio can be switched so that the receiver is set to lower heterodyne for reception in Japan or upper heterodyne for reception in the US or Europe. As a result, a single receiver design can be configured for reception of FM radio broadcasting in either Japan or the US or Europe using a common front-end circuit, without increasing the number of components.