Abstract: A matching circuit includes first and second ports, an autotransformer, and first and second capacitors. The autotransformer includes a first terminal coupled to a first port, a second terminal coupled to a second port, and a common terminal coupled to a reference potential, and includes a series parasitic inductor and a parallel parasitic inductor. The first capacitor is coupled in shunt to the second terminal, and defines a low pass filter together with the series parasitic inductor. The second capacitor is coupled in series between the first port and the first terminal, and defines a high pass filter together with the parallel parasitic inductor.

Abstract: An apparatus configured to transceive wireless power, includes a magnetostrictive resonator configured to be excited by a magnetic field, and a soft magnetic material disposed in a vicinity of the magnetostrictive resonator. The apparatus further includes a transducing coil disposed in a vicinity of the magnetostrictive resonator or the soft magnetic material, and configured to convert mechanical energy generated by the excitation of the magnetostrictive resonator to electric energy.

Abstract: In accordance with an embodiment, a circuit includes a low noise amplifier transistor disposed on a first integrated circuit, a single pole multi throw (SPMT) switch disposed on a second integrated circuit, and a bypass switch coupled between a control node of the low noise amplifier transistor and an output node of the low noise amplifier transistor. The SPMT switch couples a plurality of module input terminals to a control node of the low noise amplifier transistor, and the bypass switch including a first switch coupled between the control node of the low noise amplifier transistor and an intermediate node, a second switch coupled between the intermediate node and the output node of the low noise amplifier transistor, and a third switch coupled between the intermediate node and a first reference node. The first integrated circuit and the second integrated circuit are disposed on a substrate.

Abstract: This technique relates to a receiving device, a receiving method, and a program that can demodulate transmitted signals with high accuracy. A receiving device of this disclosure includes: an amplifying unit that amplifies a received signal; an adjusting unit that adjusts gain of the amplifying unit in accordance with power of the signal; a demodulating unit that demodulates the amplified signal; and a detecting unit that detects an interval from the signal, information having the same content continuously appearing in the interval. The adjusting unit restricts the process of adjusting the gain of the amplifying unit in accordance with a result of the detection of the interval. This disclosure can be applied to receiving devices that receive broadcast signals compliant with DVB-C2 via a CATV network.

Abstract: In an exemplary embodiment, a phased array antenna comprises multiple subcircuits in communication with multiple radiating elements. The radio frequency signals are independently adjusted for both polarization control and beam steering. In a receive embodiment, multiple RF signals of various polarizations are received and combined into at least one receive beam output. In a transmit embodiment, at least one transmit beam input is divided and transmitted through multiple radiating elements, with the transmitted beams having various polarizations. In an exemplary embodiment, the phased array antenna provides multi-beam formation over multiple operating frequency bands. The wideband nature of the active components allows for operation over multiple frequency bands simultaneously.

Abstract: A high-frequency device includes a wireless IC chip and a board which is coupled to the wireless IC chip and electrically connected to radiator plates, and an inductor and/or a capacitance are provided as a static electricity countermeasure element in the board. The inductor is connected in parallel between the wireless IC chip and the radiator plates, and its impedance at the frequency of static electricity is less than an impedance of the wireless IC chip.

Abstract: A receiver having multi-stage low noise amplifier are provided. In this regard, a representative receiver, among others, includes at least one antenna and a filter that receives and filters signals from the at least one antenna. The filtered signals include a first frequency band signal and a second frequency band signal. The receiver further includes a multi-stage low noise amplifier that receives the filtered signals from the filter. The multi-stage low noise amplifier includes a first stage low noise amplifier that receives and performs impedance matching for the first frequency band signal and second frequency band signal. The multi-stage low noise amplifier further includes a second stage low noise amplifier that receives the first frequency band signal and second frequency band signal.

Abstract: A gain-controllable stage (CLN, A1, A2 . . . , A7, ACC) comprises a reactive signal divider (CLN) followed by an amplifier arrangement (A1, A2 . . . , A7, ACC). The reactive signal divider (CLN) may be in the form of, for example, a capacitive ladder network. The gain-controllable stage (CLN, A1, A2 . . . , A7, ACC) has a gain factor that depends on a signal division factor that the reactive signal divider (CLN) provides. The reactive signal divider (CLN) forms part of a filter (LC). The signal division factor is adjusted on the basis of a frequency (F) to which the receiver is tuned and a signal-strength indication (RS).

Abstract: A power amplifier for use in a transmitter enables linear in dB output power control capability with 2 dB step sizes.

Abstract: A method and system for protecting a LNA by acquiring a radio frequency control channel signal at a tower top low noise amplifier (TTLNA) system. In response to acquiring the radio frequency control channel signal, LNA mode information is determined from the acquired radio frequency control channel signal. Based at least in part on the determination, the TTLNA is configured to either receive mode when the LNA mode information indicates receive mode or transmit mode when the LNA mode information indicates transmits mode. In an exemplary embodiment, the TTLNA is configured to receive mode only after a determination is made that there is no transmit energy present on the feedline connecting the BTS and the antenna. In another exemplary embodiment, the TTLNA is initialized in transmit mode.

Abstract: A semiconductor device interconnecting unit configured to input/output a high-frequency signal having a millimeter wave band to/from a semiconductor device is provided. The semiconductor or device interconnecting unit includes a part of a band pass filter configured to pass therethrough the high-frequency signal having a millimeter wave band by using an LC resonance circuit, and a remainder of the band pass filter, wherein the part and the remainder are separated from each other. The part is provided inside the semiconductor device, and the remainder is provided outside the semiconductor device. The part and the remainder include capacitors having variable capacitors added thereto, respectively. A pass band for the high-frequency signal having a millimeter wave band is changed by changing capacitance values of the variable capacitors.

Abstract: A radio frequency integrated circuit (RFIC) includes a silicon substrate, CMOS processing circuitry, and a bipolar power amplifier module. The CMOS processing circuitry is on the silicon substrate. The bipolar power amplifier module is on the silicon substrate and is operable in a 5 GHz frequency band.

Abstract: Controlling a tower-top low noise amplifier (TTLNA) without transmit mode or receive mode timing control signals from a base station. The TTLNA system and associated components autonomously determine the proper mode of operation (transmit/receive), and automatically control the operation of a low noise amplifier (LNA) to prevent signal distortion and/or damage to the wireless system hardware. A preferred method comprises: at a TTLNA, measuring a transmit time period based on detecting radio frequency (RF) transmit signal energy; determining a receive time duration based on the measured time period and a predetermined frame time; and, configuring the TTLNA to a receive mode by placing a low noise amplifier into a receive signal path during the determined receive time duration.

Abstract: A receiver has an offset application circuit for applying a known offset to an input signal, and a decision circuit for comparing the offset-applied input signal with a reference voltage. The level of the input signal is determined based on the known offset and on the result output from the decision circuit. With this configuration, a large common mode voltage can be eliminated in a circuit used for signal transmission.

Abstract: A communication device able to share one antenna and in addition able to sufficiently exhibit characteristics of a function as a reader, writer and a card function, a non-contact type IC card provided with that, and an information apparatus, wherein the device has a first transmission circuit 220 having first and second output terminals and outputting a carrier from the first and second output terminals in a first mode; an antenna circuit 210 including a node ND210, an inductor 211 having one end connected to the node, and having the other end connected to the second output terminal of the first transmission circuit, and a capacitor 212 connected between the node and the first output terminal of the first transmission circuit; a second transmission circuit 230 connected to the node of the antenna circuit and outputting the transmission data in a second mode; at least one reception circuit 240 connected to the node of the antenna circuit and performing reception processing with respect to data received at the

Abstract: A high gain input stage for a radio frequency transponder uses an amplifier for increasing a magnitude of an input signal. A DC bias circuit is used for controlling the operation of the amplifier. A resonant circuit is coupled between the amplifier and the DC bias circuit. The resonant circuit is used for receiving a signal generated by an electromagnetic field and for generating the input signal which is amplified by the amplifier. The resonant circuit has an inductor which is used to bias the amplifier thereby removing the need for a decoupling capacitor between the tuned circuit and the DC biasing of the amplifier. Multiple transponder inputs may be implemented in a single integrated circuit package.

Abstract: The invention relates to a ferrite antenna, comprising at least one winding (4), which is arranged around a core (2) consisting of ferrite material. A second core (3), consisting of ferrite material and running coaxially to the first core (2), is allocated to the first core (2), which carries the winding (4) and is rigidly fixed in the coil carrier (1). Said second core, which can be displaced in an axial direction in the same coil carrier (1), is positioned in such a way that the opposing front faces of the two cores are placed at a predetermined distance from one another. Said distance can be altered by displacing the second core (3) in an axial direction in order to tune the antenna. After tuning, the second core (3) can be fixed in or on the coil carrier (1).

Abstract: According to some aspects of this invention, a compact, broadband active receiving antenna uses one or more high transconductance transistors such as Field Effect Transistor(s) paired with another Transistor and arranged in a Cascode amplifier configuration. Some embodiments involve a single high transconductance transistor arranged with a high efficiency transformer in a nondissipative feedback loop to improve linearity and dynamic range. The devices have a high input resistance, low input capacitance, low noise and a very high second and third order Intercept Point. Since the gain is primarily a function of the amplifying electronics, it is not necessary to increase the directivity of the antenna to achieve higher gain.

Abstract: A wireless modem contains a power inserter circuit along with the traditional modem components. The power inserter circuit isolates the modem components from DC power that is inserted on the coaxial cable to a transverter. One embodiment of the present invention provides for a wireless modem that contains separate power connections for the modem components and the transverter. Another embodiment of the present invention provides for one power connection for the wireless modem and a DC-to-DC converter for the modem component power. The power source is selected based on the power requirements of the transverter and the DC-to DC-converter converts the input voltage into the voltage level required by the modem components. By incorporating the power inserter within the modem enclosure, power cannot be accidentally inserted into the modem.

Abstract: A high-frequency module includes a switching circuit having a phase-shift circuit. The phase-shift circuit matches only PCS/DCS reception signals so as to be passed therethrough by setting a control-voltage input terminal to a Low level when receiving PCS/DCS signals, and attenuates PCS/DCS transmission signals to the PCS/DCS reception circuit side by setting the control-voltage input terminal to a Hi level when transmitting PCS/DCS signals. Also, another phase-shift circuit, which further attenuates the PCS transmission signal when transmitting the PCS signal, is provided in the DCS Rx terminal side of the phase-shift circuit.

Abstract: A radio frequency amplifier of improved intermodulation performance is provided by connecting first and second transconductance amplifiers in antiphase so that third order intermodulation products cancel each other but the reduction in gain is relatively small. The transconductance stages comprise long tail pairs of transistors provided with tail current sources formed by transistors whose bases are connected to a bias voltage source. The first transistor has an emitter connected via a resistor to ground. The second transistor has an emitter connected via another resistor to the emitter of the first transistor.

Abstract: Integrated circuit layout for LF signal acquisition in the case of contactless data transmission Known circuit layouts for LF signal acquisition only provide for a very short communication distance between transponder and base unit, and consist of several ICs that need to be assembled. Using bipolar or MOS circuit layouts where the LF signal acquisition for the AM demodulator is effected on at least one of the two H bridge circuit branches. This increases system sensitivity and thus the communication distance between transponder and base unit. Due to the reduced voltage strength requirements with regard to the AM demodulator, it will become easy to integrate this circuit component jointly with the H bridge into an IC.

Abstract: A low noise RF input amplifier circuit has an input impedance Z.sub.IN for matched-impedance coupling to an antenna having a resistive impedance R.sub.A. The amplifier circuit has an input and output nodes, an inverting amplifier, and a feedback capacitor. The input node receives an antenna signal which the inverting amplifier amplifies by a frequency-dependent gain -A(s) approaching -A.sub.0 at low complex frequencies s. The feedback capacitor C couples the output node to the input node for negative feedback and is selected to match Z.sub.IN to R.sub.A. When the amplifier's gain A(s) has a rolloff approximated by ##EQU1## where p.sub.1 is a negative pole, the capacitance of C which matches Z.sub.IN to R.sub.A is approximately inversely proportional to both (A.sub.0 +1) and R.sub.A.

Abstract: A satellite receiver which is capable of being connected to different antenna assemblies which require different operating voltages, includes a switch mode power supply which supplies the different operating voltages. A microprocessor controls the duty cycle of the switch mode power supply to produce the different operating voltages in accordance with the required duty cycle. A memory stores values which define different duty cycles for each of the operating voltages and provides the values to the microprocessor.

Abstract: The present invention is directed to a dynamic range enhancing system for increasing the dynamic range of a transmission link, characterized as either an analog or digital link. The system includes a pre-processing unit, provided at a first location, that receives, as input, a transmit signal, and a post-processing unit, provided at a second location, remote from the first location, that receives, as input, a signal transmitted over the transmission link. The pre-processing unit includes a first signal level adjusting device for adjusting a signal level of the transmit signal to be transmitted over the transmission link and a control signal maybe provided for controlling the post-processing unit, and the post-processing unit includes a second signal level adjusting device for adjusting a signal level of the adjusted transmit signal transmitted over said transmission link.

Abstract: A vehicle radio receiver circuit includes two antennas for mounting on the vehicle. The antennas are significantly less than one quarter of a wavelength in length at the desired frequency of operation, and the outputs of the antenna elements are coupled to two inputs of an FM circuit and two inputs of an AM circuit, which includes summing circuitry. The FM circuit has an FM output for providing a received FM signal, and the AM circuit has an output for providing an AM signal that includes a sum of signals derived from the outputs of the antennas.

Abstract: The present invention is directed to a dynamic range enhancing system for increasing the dynamic range of a transmission link, and also to a process for increasing the dynamic range of a transmission link. An instruction setting process is also provided for defining a set of instructions, for a control device of the system, which detects, at an initial position along the transmission link, the level of a transmit signal adapted to be transmitted over the transmission link. The control device controls a first signal level changing device and a second signal level changing device in response to the detected level. The first and second signal level changing devices, respectively, process the transmit signal level before and after transmission over the link.

Abstract: A concealed antenna system for motor vehicle radios replaces a radio chassis preamplifier with a remote radio frequency amplifier packaged with a filter module adjacent the antenna conductors to reduce the noise floor before transmitting the signal by a highly capacitive cable to the radio chassis. The dynamic range of the antenna system is improved by an automatic gain control feedback signal from the radio chassis to the RF amplifier so that the gain of the amplifier is reduced in the presence of a strong AM signal. Preferably the antenna conductors comprise embedded conductors in an insulating panel of a motor vehicle such as the vehicle rear window, and the AM conductor may be conveniently provided by the heater grid for the window panel.

Abstract: The present invention is directed to a dynamic range enhancing system for increasing the dynamic range of a transmission link, and also to a process for increasing the dynamic range of a transmission link. An instruction setting process is also provided for defining a set of instructions, for a control device of the system, which detects, at an initial position along the transmission link, the level of a transmit signal adapted to be transmitted over the transmission link. The control device controls a first signal level changing device and a second signal level changing device in response to the detected level. The first and second signal level changing devices, respectively, process the transmit signal level before and after transmission over the link.

Abstract: An antenna, which may be a search coil, is connected to an operational amplifier circuit which provides negative impedances, each of which is in the order of magnitude of the positive impedances which characterize the antenna. The antenna is connected to the inverting input of the operational amplifier, a resistor is connected between the inverting input and the output of the operational amplifier, a capacitor-resistor network, in parallel, is connected between the output and the noninverting input of the operational amplifier, and a resistor is connected from the noninverting input and the circuit common. While this circuit provides a negative resistance and a negative inductance, in series, which appear, looking into the noninverting input of the operational amplifier, in parallel with the antenna, these negative impedances appear in a series loop with the antenna positive impedances, so as to algebraically add.

Abstract: A wristwatch paging receiver is provided with an antenna matching network that automatically retunes the network at the beginning of a listening interval. During the retuning operation, a control signal is applied to a variable tuning element in the matching network, such as a varactor diode, and is swept from a minimum value to a maximum value. This sweeping is desirably performed in discrete voltage steps that correspond to unit increments of varactor capacitance. A feedback signal from the receiver, such as an AGC signal, is monitored during this operation to note which varactor bias signal yields the maximum AGC signal. After the sweep is concluded, the apparatus applies to the varactor the bias voltage that yielded the maximum AGC signal during the sweeping operation. This bias voltage is maintained through the end of the listening interval. At the beginning of the next listening interval, the process may be repeated.

Abstract: An antenna, which may be a search coil, connected to an active circuit which provides negative impedances, each of which is of the order of magnitude of the positive impedances which characterize this active antenna. In one embodiment, one coil terminal is connected to an amplifier which drives a voltage-controlled current source that, in turn, drives a feedback coil which is coupled to the original search coil. In another embodiment that additionally exhibits an advantageous signal-to-noise characteristic, both terminals of the search coil are connected to a differential amplifier that, in turn, provides the control voltage for a current source, which, as in the first embodiment, drives the feedback winding. The feedback coil is wound to provide positive feedback by additive superposition of both coil fields.The positive feedback provided by the feedback current lowers the antenna impedance which, in turn, increases the effective area of the antenna.

Abstract: A radio receiver antenna arrangement incorporating an RF pre-amplifier (5) wherein circuitry (11 to 21) is provided for by-passing the pre-amplifier when strong signals are picked up by the antenna (1) to avoid overloading the pre-amplifier.

Abstract: A circuit array for frequency translation by means of quadrature heterodyne signals has very low quadrature errors even at very high frequencies and is monolithically integratable with little external circuitry. The circuit array includes a first mixer which receives a first portion of an input signal, a second mixer which receives a second portion of the input signal, and a heterodyne signal generator which receives a local oscillator signal and supplies quadrature heterodyne signals to the mixers. The heterodyne signal generator includes a control loop to ensure a 90.degree. phase shift between the quadrature heterodyne signals. The circuit array can be used in a modulator for a transmitter or in a demodulator for a receiver.

Abstract: A dual function antenna system and method. A system is provided for using a single antenna for both the reception of low frequency navigational signals, such as LORAN-C, and high frequency communications signals in the VHF region. The antenna is at a remote location from a low frequency receiver and a high frequency transceiver. Both the low frequency and the high frequency signals are coupled to the receiver and transceiver, respectively, over the same transmission line at one end thereof. A preamplifier is provided at the location of the antenna to increase the strength of the low frequency signal applied to the transmission line. A high pass filter is provided to couple the antenna and the transmission line and prevent feedback from the output of the preamplifier from reaching its input. The other end of the transmission line is coupled to the high frequency transceiver by a high pass filter, and to the low frequency receiver by a low pass filter.

Abstract: An FM wave antenna including a coaxial cable, a parallel conductor which are provided parallel to a metal conductor such as a vehicle body and an amplifier provided between the coaxial cable and the parallel conductor. The coaxial cable is made up of a central core and inductive outer sheath and one end of the inductive outer sheath is connected to the metal conductor, and one end of the parallel conductor is also connected to the metal conductor. The amplifier amplifies signals from the parallel conductor and inductive outer sheath of the coaxial cable and outputs amplified signals to the central core of the coaxial cable.

Abstract: An antenna assembly which is suited for receiving FM signals, comprises a pair of insulating disc shaped substrates which each have conductive patterns deposited on one surface thereof. The first insulating substrate has an electrically conductive loop element extending around approximately 360.degree. on the first substrate. The loop element terminates at first and second terminals which are adjacent each other. An electrically conductive tap element is deposited on one surface of the second substrate. The tap element extends around approximately 180.degree. and is parallel to half of the length of the loop element. On end of the tap element is electrically connected to a mid-point of the loop element intermediate its first and second terminals. Plate areas are deposited on the substrate and are electrically connected to selected terminals of the loop and tap elements to form capacitors.

Abstract: The present invention provides within three particular aspects thereof an isolating and matching device operable to enable an electrically heatable window of a motor vehicle to be used as an efficient VHF communications aerial or antenna; wherein isolating and matching circuitry is provided for Series VHF Matching, Shunt VHF Matching and Split Passband Matching of an electrically heatable window heating element to an aerial input impedance of an aerial feeder circuit of a radio frequency receiver or transmit/receive device.

Abstract: The present invention provides within three particular aspects thereof an isolating and matching device operable to enable an electrically heatable window of a motor vehicle to be used as an efficient VHF communications aerial or antenna; wherein isolating and matching circuitry is provided for Series VHF Matching, Shunt VHF Matching and Split Passband Matching of an electrically heatable window heating element to an aerial input impedance of an aerial feeder circuit of a radio frequency receiver or transmit/receive device.

Abstract: A ferrite core antenna for use in the VHF and UHF range has a first coil on the core which is connected to a capacitance selected to resonate with the inductance of the coil at the desired frequency of operation. The ferrite core antenna also has a second coil for providing a signal to the input stage of a radio receiver. In contrast to conventional loopstick antennas for low frequencies, the operation of the ferrite core antenna in the VHF to UHF range is remarkably improved by using an input stage having a relatively high input impedance and using a greater number of turns in the second coil than the first which is tuned instead of the second. Preferably the first coil is centrally disposed and has a single turn in the form of a relatively wide band of conductive metal foil, and the second coil is offset by a certain distance from the first coil and feeds an input signal to the gate of a gallium arsenide field-effect transistor.

Abstract: A fixed length antenna rod projects from a housing enclosing a pre-amplifier circuit connecting it to the front end of a FM receiver. The antenna rod is mounted at an optimum signal reception attitude by the flange of a bracket to which the housing is secured and through which an output cable terminal of the pre-amplifier circuit extends. The preamplifier circuit is adjustably tuned to favor a specific frequency for subcarrier transmission and attenuated in signal gain to match antenna signal pick-up level.

Abstract: The present invention provides within three particular aspects thereof an isolating and matching device operable to enable an electrically heatable window of a motor vehicle to be used as an efficient VHF communications aerial or antenna; wherein isolating and matching circuitry is provided for Series VHF Matching, Shunt VHF Matching and Split Passband Matching of an electrically heatable window heating element to an aerial input impedance of an aerial feeder circuit of a radio frequency receiver or transmit/receiver device.

Abstract: A wireless superheterodyne receiver is provided having an antenna for receiving wireless transmissions, a preamplifier having an input connected to the antenna and an output, a crystal filter having an input connected to the output of the preamplifier and an output, a demodulator having an input connected to the output of the filter, the demodulator having a single mixer, an oscillator having a second crystal connected to the single mixer of the demodulator wherein the demodulator supplies at an output a demodulated signal based upon the wireless transmissions.

Abstract: An automatic signal optimizing interface for connection between the antenna of an automobile radio receiver and the receiver itself processes the RF signal received by the antenna and provides an improved output signal to the automobile receiver which is optimized for distortion free reception. The output signal is limited to the desired frequency band to eliminate interfering signals, and is maintained within the optimum dynamic range of the receiver, even under reception conditions in which the received antenna signal itself is excessively high or undesirably low. The interface therefore permits superior performance by the radio receiver by optimizing the signal supplied to the radio and by preventing intermodulation distortion which otherwise commonly results from overloading of the front end of the radio receiver by excessively strong received signals.

Abstract: An aerial circuit comprises a first antenna in connection with an impedance, which is a "negative impedance", whereby a broad frequency range is achieved. The "negative impedance" is based on a second antenna similar to the first antenna, whereby the resulting aerial impedance is zero for all frequencies. A corresponding ferrite or loop aerial system is advantageously usable as a stationary system instead of an antenna of the long wire type, and the signal to noise ratio is better than with conventional ferrite antennas.

Abstract: A microwave antenna has associated therewith an integrated amplifier and frequency converter circuit for operating frequencies of from 1 Ghz to 40 Ghz. The circuit may be tuned by variation of a voltage regulated supply which is impressed onto the center conductor of a coaxial output cable. The frequency selective tuning elements are strip lines etched on one side of a double sided printed circuit board. The receiver is designed as an integral part of a quarter spherical reflector which illuminates a resonant cavity in which a stub antenna is mounted. The stub antenna is also directly connected to an input transistor of the amplifier/converter circuit.

Abstract: In a television receiver system having an antenna and a preamplifier, the antenna is chosen to receive signals from distant stations. Weak signals are amplified and applied to the receiver through an adjustable attentuator. Strong signals from near stations are held to a maximum level before amplification and before application to the receiver through the adjustable attenuator. Manual adjustment of the attenuator enables the viewer to adjust the signal to optimize the television picture.

Abstract: A single-turn loop antenna suitable for inclusion within the cabinet of a television receiver has at least one gap forming a pair of feed terminals. Circuitry connects to the feed terminals for tuning the antenna over at least a portion of the television frequency bands and for coupling signals from the feed terminals to a transmission line. The circuitry provides isolation so the tuning of the antenna by the tuning circuitry is unaffected by the impedance of the transmission line or its terminating impedance and variations thereof. The circuitry is affixed to the loop proximate to the feed terminals, and the transmission line is affixed to the periphery of the loop and departs therefrom at a neutral point located, for example, opposite to the gap.

Abstract: To minimize overmodulation in an active window antenna and radio receiver system, an amplification control voltage is produced in the active antenna, i.e., directly behind the antenna pre-amplifier, and is used to control the amplification of the pre-amplifier.

Abstract: An antenna system is disclosed for plural band radio receivers having a common antenna. The system is especially adapted for AM/FM automobile broadcast receivers and may be used with a CB transceiver with a tri-band antenna. An impedance transforming means is provided at the base of the antenna and a single transmission line or lead-in cable extends from the impedance transforming means to the AM/FM receiver. The impedance transforming means has a high input impedance for the AM and FM bands and a relatively low output impedance to minimize the signal loss in transmission from the antenna to the receiver. The impedance transforming means includes a field effect transistor in a common source configuration and means are provided to produce substantially 100% voltage degeneration for both AM and FM signals.