摘要:
An antenna device comprises an antenna element formed in a sufficiently shorter length as compared with the wavelength of transmission or reception wave, a resistor, a matching circuit including at least a reactance element, and an output terminal connected to outside, which are connected in series in this sequence. As a result, an antenna device of smaller size and small loss is obtained.
摘要:
A portable receiver includes an antenna to which at least FM broadcast wave is inputted, a matching circuit to which the signal input to the antenna is supplied via minute resistance component, an FM receiver unit with the output of the matching circuit connected thereto, and an earphone connected to the output of the FM receiver unit. The antenna is formed from rigid metal, and its length is shorter than the quarter wavelength of the FM broadcast wave. The matching circuit is formed by reactance element having fine DC resistance. The impedance value of the resistance component as viewed via the resistance component from the matching circuit is nearly equal to the impedance of the matching circuit.
摘要:
A matching device causes an antenna to match a receiving section arranged to receive a signal in a first frequency band and a signal in a second frequency band lower than the first frequency band. The matching device includes a first terminal arranged to be connected to the antenna, a first inductor connected between the first terminal and a first node, a second inductor connected between the first node and a ground, a first capacitor connected between the first node and a second node, a second terminal arranged to be connected to the receiving section, the second terminal being connected to the second node, and a third inductor connected between the second node and the ground. The second inductor has a capacitive impedance in the first frequency band, and has an inductive impedance in the second frequency band. This matching device can supply a signal in the second frequency band received by the antenna to the receiving section with a small loss. The antenna having a small length can receive a signal of low frequencies and long wavelengths in the second frequency band.
摘要:
A high-frequency receiver has both interference characteristic and reception characteristic. The high-frequency receiver includes an electronic switch that is connected in parallel to input and output terminals of antenna amplifying circuit, and an antenna control unit that controls the electronic switch and an antenna amplifying circuit. When an antenna control signal output from a high-frequency receiving unit is input to the antenna control unit, the electronic switch is opened and simultaneously power supply to the antenna amplifying circuit starts in a weak electric field area, and the electronic switch is closed and simultaneously power supply to the antenna amplifying circuit stops in a strong electric field area.
摘要:
A matching device causes an antenna to match a receiving section arranged to receive a signal in a first frequency band and a signal in a second frequency band lower than the first frequency band. The matching device includes a first terminal arranged to be connected to the antenna, a first inductor connected between the first terminal and a first node, a second inductor connected between the first node and a ground, a first capacitor connected between the first node and a second node, a second terminal arranged to be connected to the receiving section, the second terminal being connected to the second node, and a third inductor connected between the second node and the ground. The second inductor has a capacitive impedance in the first frequency band, and has an inductive impedance in the second frequency band. This matching device can supply a signal in the second frequency band received by the antenna to the receiving section with a small loss. The antenna having a small length can receive a signal of low frequencies and long wavelengths in the second frequency band.
摘要:
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.
摘要:
The present invention provides a low cost microstrip line with low loss and a microwave device using the microstrip line. The microstrip line comprises (a) a dielectric substrate for general purpose use with relatively high loss in a microwave frequency, (b) a strip conductor foil disposed on the front surface of the substrate, (c) a metal plate for grounding disposed in contact with the back of the dielectric substrate, and (d) an air layer formed on a portion of the metal plate for grounding, the portion facing to the strip conductor foil.
摘要:
A noise canceller includes an input terminal for receiving an input signal containing a received signal and a first noise signal generated by a noise source, a first delay unit for delaying the input signal, a pick-up antenna for receiving a second noise signal generated by the noise source, a cancel-signal generator for generating a noise-canceling signal based on the second noise signal, and a combiner for combining the delayed input signal and the noise-canceling signal so as to cancel the first noise signal contained in the input signal, and outputting the received signal. The noise canceller can include a second delay unit for delaying the second signal instead of the first delay unit or in addition to the first delay unit. This noise canceller cancels the noise signal generated by the noise source, thereby providing an electronic device having a preferable receiving sensitivity.
摘要:
A high-frequency receiver capable of improving both an interference-resistant characteristic and reception sensitivity is provided. A gain switch control unit includes: a signal level determination unit comparing a gain control voltage of an amplifying circuit with a reference voltage; and a gain switch controller provided between an output terminal of the signal level determination unit and a gain control input terminal provided to an amplifying circuit for gain control. When receiving a signal in a strong electric field area having a high possibility that a strong interference signal exists, a gain of the amplifying circuit is set to be smaller than that in a case of receiving a signal in a weak electric field area by a gain switch signal output from the gain switch controller.
摘要:
A high-frequency receiver capable of improving both an interference-resistant characteristic and reception sensitivity is provided. A gain switch control unit includes: a signal level determination unit comparing a gain control voltage of an amplifying circuit with a reference voltage; and a gain switch controller provided between an output terminal of the signal level determination unit and a gain control input terminal provided to an amplifying circuit for gain control. When receiving a signal in a strong electric field area having a high possibility that a strong interference signal exists, a gain of the amplifying circuit is set to be smaller than that in a case of receiving a signal in a weak electric field area by a gain switch signal output from the gain switch controller.