Abstract: In a tunable duplexer combining a tunable filter with a canceler, calibration for optimizing passband characteristics and stop band characteristics is accelerated, and the deterioration of performance due to variations is highly accurately compensated. The tunable filter is calibrated to acquire isolation characteristics, and then coarse calibration and fine calibration are performed on the canceler. In coarse calibration, the use band of the tunable filter is set to a suppression band, and the isolation characteristics of the canceler are acquired. An amplitude, a phase, and a bias voltage are adjusted based on a result of comparison with the acquired isolation characteristics of the tunable filter for determining an approximate convergence. Fine calibration is further performed, and the optimum point is determined in a narrow range near the convergence.

Abstract: A tunable filter has an out-of-band signal suppression amount of 30 dB that is smaller than 50 dB, the suppression amount of a typical duplexer. Thus, a canceller having a suppression amount of about 20 dB is necessary (particularly, a method is provided to obtain a suppression amount over a wide band without being adversely affected by the group delay characteristics and frequency characteristics of an amplifier included in a canceller). Delay devices corresponding to the group delay of the amplifier are disposed on the signal path of the tunable filter. The canceller includes a matching circuit that adjusts an amplitude, a phase, and a delay, a wide-band amplifier that has small amplitude fluctuations and small phase fluctuations over the frequency bands of a transmission signal and a reception signal, a variable-impedance transmission coupler, and a variable-impedance reception coupler.

Abstract: A tunable filter and a tunable duplexer are provided, both of which comprise an input terminal, an output terminal, four fixed capacitors, three variable capacitors and three fixed coils; wherein the variable capacitors are grounded at one end and, at the other end, connected to the fixed coils to form three sets of series-connected LC circuit; wherein the connecting points of the three sets of series-connected LC circuit, the input terminal and the output terminal are connected with the fixed capacitors, respectively.

Abstract: A tunable filter in a tunable DPX module has frequency characteristics, and thus needs to be controlled with high accuracy so as to simultaneously cancel a transmission signal and noise in a reception band on a transmission side. For this reason, a canceller includes a filter having the same frequency characteristic as that of a tunable filter, and a structure having functions of compensating for an amplitude, a phase, and a delay. And, two lines of the cancellers are used to individually cancel a leak component of a transmission signal and a leak component of thermal noise in a reception band. In order to save the power consumption of the amplifier, a coupler is loosely coupled, and a combiner is tightly coupled. Further, in order to suppress the influence on a reception system due to the tough coupling, the combiner uses the amplifier for in-phase inputs.

Abstract: For providing a module for use of a mobile communication terminal, being small in sizes and high in reliability, and enabling with plural numbers of bands, and also a mobile communication terminal with using the same therein, canceling is conducted on transmission signal and/or noises of reception band on reception side with using a feed forward technology, for maintaining a degree of suppression of the transmission signal and/or the noises of reception band on the reception side. In this case, for achieving the cancellation of wide band signals from the transmission signal to the reception band, a delay adjusting function is used, in addition to gain and phase adjusting functions. Also, for conducting stable canceling of jamming signals, controls are conducted on the gain, the phase and the delay of a loop with using a reception SN and/or a CQI signal, etc. Further, for achieving low power consumption, a feed forward loop can be made ON/OFF depending on a level of the transmission signal.

Abstract: A high-frequency circuit has a duplexer and a filter. The duplexer performs wave separation of send and received signals as input thereto. The filter filters the input send signal. When the send and received signals of the first modulation method are input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer. When the received signal of the first modulation method is input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer, and the send signal of the second modulation method is filtered by the filter.

Abstract: A small-sized, high-performance transmission circuit is provided which avoids degradation in transmission line characteristics caused by coupling, due to a transmission line and a leader electrode to an external electrode which are oppositely facing, of the electromagnetic field induced by the transmission line and the electromagnetic field induced by the leader electrode. In order to attain the aforementioned object, the present invention comprises a first shield layer which is a first ground electrode, a second shield layer which is a second ground electrode, and a spiral-shaped transmission line facing the first shield layer and the second shield layer which is disposed between the first shield layer and the second shield layer. The spiral portion of the transmission line, when viewed from the top face or the bottom face of the transmission line, is disposed on the inside of the first shield layer and the second shield layer.

Abstract: A high-frequency circuit has a duplexer and a filter. The duplexer performs wave separation of send and received signals as input thereto. The filter filters the input send signal. When the send and received signals of the first modulation method are input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer. When the received signal of the first modulation method is input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer, and the send signal of the second modulation method is filtered by the filter.

Abstract: A small-sized, low-cost radio frequency switch circuit, which has good characteristics of isolation between a transmission circuit and a reception circuit, includes a multi-layered substrate; a transmission line provided on the top surface of, or within, the multi-layered substrate; a first diode and a second diode connected respectively to both ends of the transmission line; a resistor, connected to the first diode, to apply a current to the first diode and the second diode; a first capacitor whose one end is connected to the resistor and whose other end is grounded; and a second capacitor connected in parallel to the transmission line.

Abstract: A high-frequency appliance, which is allowed to have an ESD tolerance by using a small-sized and low-cost ESD protection circuit, and in particular, an antenna duplexer having a multi-band high-frequency switch function. There are provided a signal separation unit for separating a first frequency band signal from a second frequency band signal, the second frequency band being lower than the first frequency band, a first SAW filter for inputting the first frequency band signal outputted from the signal separation unit, a second SAW filter for inputting the second frequency band signal outputted from the signal separation unit, and a high-pass filter for permitting passing of the second frequency band signal, and limiting passing of a signal whose frequency band is lower than the second frequency band, the high-pass filter being located on a signal line connecting the signal separation unit and the second SAW filter to each other.

Abstract: A compact, inexpensive antenna sharing device meeting requirements in terms of transmitter distortion characteristic and ESD characteristic is provided which separates and combines signals transmitted and received in first to third signal bands and which thereby enables an antenna terminal to be shared as a common terminal. It includes a diplexer realizing an attenuation characteristic for protection against ESD, a compound semiconductor switch with an IIP3 of 66 dBm or more, and an inexpensive PIN diode switch.

Abstract: A high-frequency circuit has a duplexer and a filter. The duplexer performs wave separation of send and received signals as input thereto. The filter filters the input send signal. When the send and received signals of the first modulation method are input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer. When the received signal of the first modulation method is input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer, and the send signal of the second modulation method is filtered by the filter.

Abstract: A small-sized, low-cost radio frequency switch circuit, which has good characteristics of isolation between a transmission circuit and a reception circuit, includes a multi-layered substrate; a transmission line provided on the top surface of, or within, the multi-layered substrate; a first diode and a second diode connected respectively to both ends of the transmission line; a resistor, connected to the first diode, to apply a current to the first diode and the second diode; a first capacitor whose one end is connected to the resistor and whose other end is grounded; and a second capacitor connected in parallel to the transmission line.

Abstract: A high-frequency circuit has a duplexer and a filter. The duplexer performs wave separation of send and received signals as input thereto. The filter filters the input send signal. When the send and received signals of the first modulation method are input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer. When the received signal of the first modulation method is input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer, and the send signal of the second modulation method is filtered by the filter.

Abstract: A high-frequency circuit has a duplexer and a filter. The duplexer performs wave separation of send and received signals as input thereto. The filter filters the input send signal. When the send and received signals of the first modulation method are input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer. When the received signal of the first modulation method is input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer, and the send signal of the second modulation method is filtered by the filter.

Abstract: A high-frequency circuit has a duplexer and a filter. The duplexer performs wave separation of send and received signals as input thereto. The filter filters the input send signal. When the send and received signals of the first modulation method are input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer. When the received signal of the first modulation method is input, the send signal and the received signal of the first modulation method are wave-separated and output by the duplexer, and the send signal of the second modulation method is filtered by the filter.

Abstract: A small-sized, high-performance transmission circuit is provided which avoids degradation in transmission line characteristics caused by coupling, due to a transmission line and a leader electrode to an external electrode which are oppositely facing, of the electromagnetic field induced by the transmission line and the electromagnetic field induced by the leader electrode. In order to attain the aforementioned object, the present invention comprises a first shield layer which is a first ground electrode, a second shield layer which is a second ground electrode, and a spiral-shaped transmission line facing the first shield layer and the second shield layer which is disposed between the first shield layer and the second shield layer. The spiral portion of the transmission line, when viewed from the top face or the bottom face of the transmission line, is disposed on the inside of the first shield layer and the second shield layer.

Abstract: A compact, inexpensive antenna sharing device meeting requirements in terms of transmitter distortion characteristic and ESD characteristic is provided which separates and combines signals transmitted and received in first to third signal bands and which thereby enables an antenna terminal to be shared as a common terminal. It includes a diplexer realizing an attenuation characteristic for protection against ESD, a compound semiconductor switch with an IIP3 of 66 dBm or more, and an inexpensive PIN diode switch.

Abstract: A mobile station for preventing reduction of the line quality when it is used near the head of a human operator. Plural antennas are arranged so that the cross-correlation of the received waves becomes small. The signals received by the antennas are delayed by a delay time to prevent interference between the received signals so that the time difference of each received signal becomes at least one chip time of the spreading code or more. After that, a combiner combines the received signals, and an output signal of the combiner is inputted into a rake receiver. A reduction of the extent of the delay spreading is prevented by directivity of the antennas in use near a human body, and a decline of path diversity gain by the rake receiving is reduced.

Abstract: A surface acoustic wave antenna duplexer constituted by a transmitter-line filter, a receiver-line filter and an antenna terminal, the transmitter-line filter and the receiver-line filter being connected in parallel with the antenna terminal as a common terminal; wherein at least one of the transmitter-line and receiver-line filters includes a top filter using the whole of a transmitter band or a receiver band as its pass band, a surface acoustic wave resonator filter, and a transmitter or receiver terminal, the top filter, the surface acoustic wave resonator filter and the transmitter or receiver terminal being disposed in this order viewed from the antenna terminal, the surface acoustic wave resonator filter including at least one additive capacitance or inductance; and wherein a switching element is provided for varying a value of the capacitance or inductance so as to provide a function for varying a pass band frequency or an attenuation band frequency of the surface acoustic wave resonator filter.