Abstract: Apparatus is provided for transmitting signals between a cell phone (P), through a coaxial cable (16) through a window inner coupling (20) mounted on the inner side (I) of a window, to an outer coupling (22) on the outer side (O) of the window which connects to an antenna (24), which efficiently couples signals of both the lower cell phone frequency band of about 850 MHz and the high cell phone frequency band of about 1920 MHz that are in current use. The window coupling includes an electrically conductive inner plate (30) lying substantially facewise adjacent to the window and a conductive box device (40) lying around the inner face of the inner plate. The inner plate is of substantially rectangular shape, with a plurality of sides (111-114) extending in series around the inner plate.

Abstract: The present invention use the properties of a TDD-transmission on a specific mixer in such a manner that in the transmit mode a first RF signal is amplified in the mixer with an amplification factor greater than, or equal to, or less than one, and in the receive mode the received RF signal is mixed with a second RF signal.

Abstract: An antenna diversity arrangement is applicable to frequency hopping receiver (34) for receiving data packets transmitted on frequency channels lying within an overall frequency bandwidth, divided into a plurality of sub-bands. In each sub-band the frequency characteristics of the channel will be substantially the same. The choice of antenna (10, 12) for a particular sub-band is done by carrying-out frequency diversity measurements and the selection is treated as being valid for a period of time which may be preset or determined dynamically. In operation the hopping sequence is known to the receiver so that it can determine in advance the frequency of the next data packet to be received and can select the particular antenna without the necessity of carrying out diversity measurements. At the end of the time period the suitability of the selected antenna is checked and if necessary the selection is updated in the receiver.

Abstract: A radio communications device, such as a mobile phone or Bluetooth device, comprises a ground conductor (302) incorporating a slot (304) and means (308) for coupling a transceiver to the slot to enable the ground conductor to function as an antenna. Such a device enables efficient radiating performance to be obtained from a significantly smaller volume than known antenna arrangements.

Abstract: An array directivity switching determining section 114 stores reception quality information outputted from a separating section 113, determines whether to change a directivity or beam width of transmission array antenna based on reception quality information, and outputs an information to indicate either to change the directivity or beam width of transmission array antenna to an array directivity switching controlling section 115 in accordance with the determination result.

Abstract: A filter unit comprises a wideband bandpass filter; at least one band-elimination filter having a stop band within the passband of the bandpass filter, so that the passband is divided into a plurality of pass bands by the stop band; and the wideband bandpass filter and the band-elimination filter being disposed in a single dielectric member. Since the passband of a wideband bandpass filter is divided into a plurality of pass bands by stop bands of one or more band-elimination filters, signals having frequencies corresponding to these divided pass bands are able to pass through the filter unit simultaneously.

Abstract: A composite high frequency component, comprising: a first high frequency switch having a first common port and firsts second, and third communication ports, wherein: the first communication port is operable to connect to respective transmitting sections of first and second communication systems which operate in substantially the same frequency band, the second communication port is operable to connect to a receiving section of the first communication system, the third communication port is operable to connect to a receiving section of the second communication system, and the first high frequency switch has a transfer characteristic for passing signals between the first common port and the first, second and third communication ports which are in the frequency band of the first and second communication systems as a function of at least one first control signal; a second high frequency switch having a second common port and fourth and fifth communication ports, wherein: the fourth communication port is operable

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 composite high frequency component, comprising: a first high frequency switch having a first common port and first, second, and third communication ports, wherein: the first high frequency switch has a transfer characteristic for passing signals between the first common port and the first, second and third communication ports which are in the frequency band of the first and second communication systems as a function of at least one first control signal; a second high frequency switch having a second common port and fourth and fifth communication ports, wherein: the second high frequency switch has a transfer characteristic for passing signals between the second common port and the fourth and fifth communication ports which are in the frequency band of the third communication system as a function of at least one second control signal; a first filter having characteristic for passing signals in of the first and second communication the first filter being coupled to the of the first high frequency switch; a tr

Abstract: A method and apparatus are disclosed for efficient transmission over a range of power levels with a diode-based T/R switched transceiver (e.g., PIN-diode switch), whereby a small amount of current flows through the switch at the lower power levels, and a large amount of current flows through the switch at the higher power levels. In a transceiver that can transmit at different power levels, a control unit sets the power amplifier to a specific gain for a specific power level. The control unit knows what power level the transceiver's power amplifier is set to. Consequently, using a controllable current source, the control unit can set the current through the switch to a suitable value that minimizes the total current consumption, including the current consumption in both the power amplifier and the switch.

Abstract: A transmit-receive switching circuit of a wireless communication system comprises a selecting portion for switching the communication system in a waiting mode into a master; a controller for determining a transmit-receive frequency according to the operating of the selecting portion and generating a control signal; a band selecting portion for selecting an inputting signal of an upper band or a lower band of a receiving signal passed through an antenna and a duplexer according to the control signal of the controller; a first switching portion for selecting an upper band pass filter and a lower band pass filter that are operated by the band selecting portion; an amplifying portion for amplifying a receive signal passing through the switching portion; a second switching portion for switching the receive signal amplified at the amplifying portion according to the operating signal of the band selecting portion and determining to be supplied to an upper band filter or a low band pass filter of a second filtering p

Abstract: A radio base station having a plurality of directional sector antennas for providing communications with outstations lying at different azimuth angles to the base station is disclosed in which the antennas transmit signals using one or both of two orthogonal polarizations such as left hand or right hand circular antennas and polarization and which also measures interference levels on different frequency channels that are used for allocating an optimum channel and polarization for connecting a call. Each of the outstations comprise at least one antenna of selectable polarization.

Abstract: A communication system for communicating RF signals at a plurality of communication standards through a common antenna is disclosed. The communication system includes a transmitter having transmitter outputs for generating transmit band signals in the transmit bands of each supported communication standard, and a receiver having receiver inputs for receiving receive band signals in the receive bands of each supported communication standard. The communication system also includes a plurality of RF switches. Each RF switch couples either the transmitter output or the receiver input associated with a particular communication standard to the antenna. Whether the communication unit is in transmit mode or receive mode, a harmonic filter coupled between each RF switch and the common antenna filters out harmonics of the transmit band and receive band signals.

Abstract: To effectively suppress harmonics in a dual band mobile phone with a power amplifier (10) outputting transmitting signals for different frequency bands (GSM; PCS, DCS) via a single output as described a power amplifier output circuit in which harmonics are filtered through impedance transformation of a turn-off impedance of a transmitter/receiver change over unit (36, 38). Hereby the desired filtering of harmonics may be achieved without almost no additional expenditure.

Abstract: The complete outdoor radio unit for LMDS is a light weight, compact transceiver featuring planar circuitry. The transceiver uses cross polarization through an orthomodal transducer and frequency offeset beteen transmit and receive to provide isolation between the transmitter and receiver. The transceiver includes three printed circuit boards directly attached by thermally conductive epoxy to a heat sink which forms part of the antenna dish/transceiver housing for effective heat transfer. One of the three circuit boards is a millimeter wave circuit board, which is attached to the heat sink by a millimeter ground plane. The millimeter ground plane has a plurality of cavities defined therein which form the lower portion of waveguide assemblies. Two of the waveguides are used as receiver and transmitter transmission lines into the orthomodal transducer, and two of the waveguides are used as bandpass filters. The waveguides interface with the millimeter wave board through microstrips.

Abstract: The application relates to a controllable filter (1) that is placed between an antenna on the one side and a receiver and transmitter on the other, where the receiver branch can be switched between two filter characteristics. In this way, a simple device for allowing simplex reception in the transmission band can be provided. This filter is preferably applied as a frontend filter (FP) in the fixed part of a cordless telephone system and/or in a mobile station to thereby provide said mobile station with walkie-talkie capabilities.

Abstract: A peak limiter is intended to limit the peak of a signal that has a given frequency, in an assembly comprising other signals of lower amplitude and different frequencies. The peak limiter includes a circulator inserted into a line transporting all the signals. A first branch of the circulator is connected to a line on its upstream side. Its second branch is connected to a line on its downstream side. It's third branch is connected to a reference terminal via the combination of a band-pass filter centered on the given frequency, a threshold element, and an adapted load connected in series.

Abstract: The present invention is directed to providing a full duplex communication system capable of providing actual wireless transmission rates on the order of 125 Mb/s, or higher, with relatively high transmission power on the order of 0.5 to 2 watts (W) or higher, with a high signal-to-noise(S/N) ratio, a bit error rate on the order of 10−12 or lower, 99.99% availability, and with relatively simple circuit designs. Exemplary embodiments can provide these features using a single compact and efficient, low distortion transceiver design based on high power (e.g., 0.5 W) monolithic millimeter wave integrated circuits (MMICs), having a compression point which accommodates high speed modems such as OC-3 and 100 Mb/s Fast Ethernet modems used in broadband networking technologies like SONET/SDH (e.g., SONET ring architectures having self-healing ring capability). By applying high power MMIC technology of conventional radar systems to wireless duplex communications, significant advantages can be realized.

Abstract: Transmission and reception device for a mobile radio base station comprising a plurality of transmission and reception units and hence a plurality of carriers, the transmission and reception units being accommodated in push-in modules and each having a modulator (10), a channel frequency device (19) and an output stage (20). At least some of the push-in modules comprise two full transmission and reception units having a first and a second transmission branch (1, 2). The two transmission branches (1, 2) are connected to a transmission connection (4) via an incorporated hybrid combiner (3) in order to provide two mutually combined carriers in a first mode of operation for relatively high capacity. In a second mode of operation for high output power, the two transmission branches (1, 2) are additionally connected to one another by means of an internal changeover device (25, 26, 27) such that the same transmitted signal is routed at least via the output stages (20) of both transmission branches (1, 2).

Abstract: The invention relates to an antenna changeover switch for transceivers in a mobile station, designed for operation in at least two discrete HF transmission bands. For this purpose diode switches (D1 to D4) with HF impedance transformers are often used, which switch between channels of the GSM 900 network and channels of the DCS 1800 network. Owing to inadequate decoupling between the transceivers an appreciable portion of the transmitting signal from the active transceiver (TX1 or TX2) will arrive at the antenna terminal of the inactive transceiver. Therein in particular a portion coupled into the antenna terminal (A2) of the DCS 1800 transceiver by the GSM 900 transceiver can be so large that the currentless semiconductor components connected there generate harmonic waves.

Abstract: Receiving apparatus for receiving satellite broadcasting electric wave to be mounted mobile vehicle being realized at low cost and not influence by the weather etc. The apparatus is provided with an antenna of which directivity pattern can be varied, and by a geomagnetism sensor mechanically coupled with said antenna to detect present orientation of the antenna, and comprising antenna controlling means by which the directivity pattern of the antenna is directed towards objective broadcasting satellite based on said detected orientation output. When an electric wave from a gap-filler station is to be received, the antenna is controlled to become non-directivity pattern automatically. For the antenna, a microstrip patch antenna having a plurality of conductive patches arranged in a plane is used.

Abstract: A circuit and method for reducing local oscillator frequency transmission in a homodyne, or direct conversion, radio transceiver using I/Q modulation/demodulation minimizes local oscillator leakage to the antenna and its subsequent reception by the receiver by interfacing I/Q input signals to the modulator in a controlled manner so as to increase isolation during reception by presenting high impedance states to the I/Q modulator input terminals during reception thereby nulling the carrier during reception.

Abstract: An antenna switch includes at least one signal path, including an amplifier device and a switch. The amplifier device includes an amplifier connected to a first inductor and to a first capacitor, which is grounded. The amplifier is voltage supplied via a second inductor. The switch includes a receiving isolation device, which is connected to a bypass capacitor connected to an antenna via a low pass filter. A first microstrip is connected to the bypass capacitor and to a DC switch. The first inductor and the first capacitor together with a shorted output transistor of the amplifier form a high impedance in receiving mode, thereby not affecting the receiving signal. The receiving isolation device is a signal wire.

Abstract: The invention relates to an arrangement for radio frequency signals particularly in a duplex filter summing part comprising a conductive housing and at least one common transmission line for at least two different signals. In order to reduce intermodulation distortion of signals, which arises in the summing part, the housing of the summing part is arranged to function as a ground plane for the transmission line without the ground plane of a printed board or a ground plane otherwise connected to the transmission line.

Abstract: The invention concerns an arrangement for coupling external antennas (14, 15) to a communication unit (20).

Abstract: To achieve an improved matching of a power amplifier to transmission line impedances of different transmission branches in a dual band mobile phone there is proposed a new power amplifier output circuit for such a dual band mobile phone. This power amplifier output circuit comprises a transmission branch change over unit being connected to an output terminal of the power amplifier. Further, there is provided a second impedance matching means in at least one transmission branch and the transmission branch change over unit comprises at least two switching elements between the first impedance matching unit and the second impedance matching unit. Therefore, the disturbing influence of parasitic elements in the switching elements may be reduced significantly.

Abstract: A matched pair circulator antenna isolation circuit provides isolation between an antenna and one or more receivers and transmitters and may also be applied to other RF devices. A portion of the transmit signal is extracted by a first RF circulator and divided into two phase-inverted signals. The first phase-inverted signal is coupled through a first directional coupler to cancel most of the transmit signal present in the receive signal. The second phase-inverted signal is coupled through a second directional coupler to cancel remaining transmit signal in the output of the first directional coupler. The output of the second directional coupler is coupled to the input of the receiver.

Abstract: An antenna-duplexer and communication apparatus in which relative phase distortion of transmitted waves and intrusive waves is low, and which are small-scale. An antenna-duplexer comprises a transmission side circuit, electrically connected between a transmission terminal and an antenna terminal, and a reception side circuit, electrically connected between a reception terminal and the antenna terminal. Two PIN diodes, which are connected in series, are connected only to a resonator of the transmission side circuit which is electrically connected closest to the antenna terminal, and a voltage control terminal is connected to the anodes of the PIN diodes, thereby dividing the high-frequency voltage. One PIN diode is connected to each of the other resonators.

Abstract: A transceiver is disclosed for use in a wireless handset. The transceiver includes a switch for connecting an antenna, one at a time, to a receiver or to a transmitter. In a reception sub-frame, a limiting circuit switches the switch to an attenuated mode when an output signal of the receiver, such as a logarithmic RSSI signal, exceeds a predetermined value. The limiting circuit includes a comparator for comparing the logarithmic RSSI signal with the predetermined value. In addition, the limiting circuit also includes a transistor which shunts to ground a first control input of the switch when the RSSI signal exceeds the predetermined value. The limiting circuit further includes a shunt circuit to maintain the attenuated mode during a transmission sub-frame to reduce the level of a signal from the transmitter.

Abstract: The specification relates to a radio frequency (RF) multiport, multiband semiconductor and transmission circuit. Each port in the multiport circuit is linked to a second port utilizing a semiconductor switching leg. A semiconductor switching leg is biased to either transport thereover an RF signal or to prevent its transport. In an embodiment of the present invention utilizing diodes as an active device within each semiconductor switching leg, a DC biasing signal is applied through an inlet and outlet inductor, thus allowing DC current to pass through the diode for biasing, but preventing RF signal loss to ground. Capacitors are used for RF signal coupling and DC blocking. One embodiment of the present invention is utilized with a dual band cellular/PCS device, with either band selectable for transmission and reception over either an internal antenna or, in the alternative, an external antenna port.

Abstract: A wireless device includes a switching portion which has a common switch (4) operated in both transmission and reception of radio signals and a reception dedicated switch (3) operated only in signal reception. A switch controller (11) is also included in the wireless device and controls the common switch to connect between the transmitting portion and one of the antennas that is selected and further controls the reception dedicated switch to separate the receiving portion from the common switch on signal transmission. The switch controller further controls both the common switch and the reception dedicated switch to connect between the receiving portion and one of the antennas that is designated on signal reception.

Abstract: A transmission output detecting circuit for use in a radio transmitter-receiver of a TDD communication system having a TDD switch for connecting a transmission system to an antenna system in a transmitting period and for connecting a reception system to the antenna system in a receiving period; comprising a detection means for detecting transmission output on the basis of leakage power of the TDD switch in the transmitting period. The transmission output can be detected with low power consumption without making the transmission power branch out.

Abstract: A mobile radio telephone includes a transmitter output stage and an antenna. An impedance matching network is inserted between the transmitter output stage and the antenna. The matching network has a transformation factor (T) for adjusting the transmitter load impedance (ZPA) to match with the antenna input impedance (ZAAnt). The impedance matching network includes at least two impedance transformers that form at least two transformation factors by alternatively connecting in parallel the two impedance transformers.

Abstract: In a movable radio terminal device, a switching circuit connects, in response to one of first and second matching switching control signals, an antenna 2 to one of first and second impedance matching circuits. The controlling unit produces and supplies, at every predetermined time interval, the first and second matching switching control signals to the switching circuit, respectively, to make a memory device memorize, as first and second level signals having first and second level values, detected level signals from a level detecting circuit when the switching circuit connects the antenna to the first and second impedance matching circuits, respectively, when the detected level value from the level detecting circuit is smaller than one of the first and second level values that corresponds to the second greatest level value in the first and second level values, and when the controlling unit is supplied with a human body contact discriminating signal from a human body contact discriminating circuit.

Abstract: A communication system capable of communicating RF signals at any one of a plurality of communication standards through a common antenna is disclosed. The communication system includes a transmitting unit having at least one transmit RF information signal output, and a receiving unit having at least one receive RF information signal input and a GPS RF information signal input. The transmitting unit includes a modulator for modulating a transmit IF with a transmit baseband information signal to generate a transmit IF information signal and an upconverter for upconverting the transmit IF information signal with a transmit RF to generate at least one transmit RF information signal.

Abstract: The present invention is a method and apparatus for isolating high frequency signals in a printed circuit board. A barrier strip (36) of staggered elongated grounding slots is positioned on the circuit board to prevent stray signals from leaking from one portion of the board to another. To further improve signal isolation, additional grounding holes (80) are placed around those areas where a trace on a circuit board makes the transition from one layer to another layer in a multilayer circuit board. In addition, microstrip filters (56, 58) are attached to the power or control traces of circuitry on the board at positions where the traces cross from one section of the board to another in order to filter out any stray rf signals that may be induced by the transmitter onto the power and control traces.

Abstract: A fully duplex cordless telephone has a transmitter and a receiver connected to a common antenna. A broad-band antenna coupler such as a ferrite-core hybrid transformer may replace a more costly duplexer with filters. Since all characteristics of the transmit signal are known, the transmit signal removes itself from the receiver by signal cancellation. The canceling signal is extracted from the composite signal from within the receiver front end, after the antenna coupler and low noise amplifier. This composite signal is coupled to the first input of a difference amplifier, and the output of this amplifier is coupled to the remainder of the receiver. The composite signal is coupled to the second input, after its smaller receive component has been further suppressed, and its remaining transmit signal has been adjusted by two feedback control systems to restore its phase and amplitude to be equal to the transmit component of the composite signal.

Abstract: An image reject transceiver (10) provides both phase and gain adjustments that causes unwanted images to be rejected. A reference signal (RF.sub.IN) is frequency translated by two mixer circuits (28, 34) in a receiver circuit (16) to provide both an in-phase and an out-of-phase replica signal of the reference signal (RF.sub.IN) during normal operation. In a calibration mode a single frequency generated by a transmitter VCO (22) replaces the reference signal (RF.sub.IN). A phase detector circuit (38) provides a phase difference value that is fed back through a first switch (45) to a phase shift circuit (36) for adjusting the phase separation between the two replica signals. An amplitude detector circuit (40) provides an amplitude error value that is fed back through a second switch (47) to the mixer circuit (34) for adjusting and matching the gain of the two replica signals.

Abstract: A communications device transmitting and receiving RF signals having an antenna including an antenna core, a plurality of first polarized antenna elements wound about the antenna core in a first direction, a plurality of second polarized antenna elements wound about the antenna core in a second direction, and a plurality of RF PIN diodes inserted in the plurality of first and second polarized antenna elements at the points where the plurality of first polarized antenna elements and the second polarized antenna elements overlap. A communications device and method for decreasing fading of a call due to multipath by switching between polarizations of the antenna when the power level of the RF signals drops below a predetermined threshold. A communications device and method for decreasing fading of a call by averaging power levels on both polarizations of the antenna.

Abstract: A circuit (30) and method for translating a spectrum of a modulated signal. The circuit (30) includes a mixer (33), a summing device (36), and a synthesizer (37). The circuit (30) receives and transmits modulated Radio Frequency (RF) signals. The synthesizer (37) generates a transmitter modulated RF signal (TX.sub.RF) using a modulating signal (TX.sub.MOD). The mixer (33) generates an intermediate frequency signal (IF) by mixing a receiver modulated RF signal (RX.sub.RF) with the transmitter modulated RF signal (TX.sub.RF). The summing device (36) removes modulation of the transmitter modulated RF signal (TX.sub.RF) by combining the intermediate frequency signal (IF) with the modulating signal (TX.sub.MOD).

Abstract: A communication unit (200) employs a method and apparatus for increasing an output impedance of a transmit amplifier during a receive mode of the communication unit. The communication unit includes a transmit amplifier, an antenna (209), and a signal receiver (211), and is operable in at least a transmit mode and a receive mode. During the transmit mode, the transmit amplifier, which includes an amplifying device (201), amplifies an input signal (221) and provides the amplified signal (233) to the antenna for transmission. During the receive mode, the antenna receives signals and provides the received signals to the signal receiver. To mitigate the transmit amplifier's effect on the received signals during the receive mode, the communication unit, during the receive mode, couples the transmit amplifier to the antenna and applies a bias (225) to the amplifying device to increase the output impedance (Z.sub.

Abstract: A user terminal in the form of a handset 1 is disclosed wherein a common antenna 3 is operative to provide transmission and reception on a plurality of selectable services at different frequencies, the antenna being resonant and matched for at least one of the services, and non-resonant and unmatched for other services. The user terminal handset 1 employs a common antenna 3 directly for that service or those services for which the antenna 3 is matched and resonant. The user terminal handset 1 employs the common antenna 3 unmatched and non-resonant for those services whereon unmatched non-resonant antenna use is acceptable. The user terminal handset 1 comprises means, for approximately or precisely adjusting the match to the common antenna 3 for other services.

Abstract: In order to minimize the chip area and improve the linear characteristics obtained when large signals are inputted, a high frequency switch device comprises first, second and third terminals (3, 4, 6); a first circuit composed of a first FET (11), and a first inductor (21) and a first capacitor (25) both connected with the first FET (11) in parallel to each other, one end of the first circuit being connected to the first terminal (3); and a second circuit composed of a second FET (12), and a second inductor (22) and a second capacitor (26) both connected with the second FET (12) in parallel to each other, one end of the second circuit being connected to the first circuit and the other end of the second circuit being connected to the second terminal (4).

Abstract: Known is a radio communication device such as a GSM handset with receive-transmit antenna switching means such as a duplexer or a transmit receive switch. In GSM handsets it is highly desirable to save battery power as much as possible. To this end in the receive and transmit paths, the power supplied to components is switched off when functioning of such components is presently not needed. Proposed is a radio communication device in which the receive-transmit switch is a couple of electromechanical switches, preferably ultra-miniature Reed relays, of which the actuating coils are connected in series with at least one DC-supplied circuit of the receive path or transmit path.

Abstract: A duplex antenna circuit assembly (1) selectively operational in a transmit or a receive mode. The assembly (1) has a transmitter amplifier (2) with an output coupled to an input of a transmitter impedance matching circuit (3) and there is a dual purpose transmitter tuning circuit (4) having an input coupled to an output of the transmitter impedance matching circuit (3). The assembly (1) also has a receiver amplifier (8) with an input coupled to an output of a receiver impedance matching circuit (9) and there is a dual purpose receiver tuning circuit (10) having an output coupled to an input of the receiver impedance matching circuit (9). There is also an antenna (5) having a first terminal output (6) coupled to the output of the transmitter tuning circuit (4) and a second terminal (7) coupled to an input of the receiver tuning circuit (10).

Abstract: A telephone system and a voice encoding/decoding method capable of reducing the consumed power by reducing the memory capacity of buffer and generating high-tone-quality voice. The system writes an input voice frame to an input buffer and eliminates the delayed disturbance in a voice signal from the input voice frame based on the output voice frame to execute echo-canceling, and decodes the received voice packet data, so that the boundary of input voice frames can be set before the boundary of output voice frames, at least, for the time necessary for the echo-canceling and decoding. Thereby, the output voice frame can always be written at the same time as the input voice frame written to the input buffer and the delayed disturbance in the voice signal can be eliminated from the input voice frame based on the output voice frame and, thus the high-tone-quality voice can be generated.

Abstract: An antenna duplexer has a transmission input terminal, a receiving output terminal, an antenna terminal in which a transmission output terminal and a receiving input terminal are used in common, a transmission filter having at least one resonance element set between the transmission input terminal and the transmission output terminal and coupled by a coupling element, a receiving filter having at least one resonance element set between the receiving output terminal and said receiving input terminal and coupled by a coupling element, and an impedance variable element connected to the resonance element of the transmission filter and the resonance element of said receiving filter respectively in parallel, wherein the frequency transfer characteristic of the transmission filter and the frequency transfer characteristic of the receiving filter are controlled by applying control signals and thereby changing the impedances of the impedance variable element.

Abstract: Disclosed is a transmitter for switching and transmitting signals of plural frequency bands. For example, the signals of two frequency bands are switched and transmitted. For the transmission in a first frequency band, of transistors 104, 105 are turned off, whereby a power amplifying transistor 102 is matched by an input wide band matching circuit 101 and an output main matching circuit 103, so that the high efficiency linear amplification is accomplished. For the transmission in a second frequency band, the transistor 104 is turned on while the transistor 105 is turned off, whereby the power amplifying transistor 102 is matched by a capacitance 108 as well as the input wide band matching circuit 101 and the output main matching circuit 103, so that the high efficiency linear amplification is accomplished. An external switch for switching the matching circuits is thus unnecessary.

Abstract: An integrated point-to-point microwave radio frequency unit/antenna has a housing, a microwave antenna affixed to the front face of the housing, and a microwave radio frequency transceiver electronics package within the housing. The transceiver electronics package includes a circuit board having transmitter and receiver intermediate frequency processors. The transceiver electronics package further includes a microwave transmitter and a microwave receiver, each utilizing monolithic microwave integrated circuit architecture. The signals of the microwave transmitter and microwave receiver are preferably of different frequencies and are diplexed for communication with the antenna.

Abstract: This separating device is provided with a transmitting filter and a receiving filter. Each of the transmitting and receiving filters comprises a variable capacity diode and a resonant element, and compose a band elimination filter. Each of the elimination bands of the transmitting and receiving filters can be adjusted by changing the capacity value of each variable capacity diode. The elimination band of the transmitting filter is adjusted so as to coincide with the receiving frequency of the communication channel currently used. The elimination band of the receiving filter is adjusted so as to coincide with the transmitting frequency of the communication channel currently used.