Abstract: An input signal having an intermediate signal superposed on a DC voltage is applied to a variable attenuation circuit through an amplifier. An output of the variable attenuation circuit is detected by a detecting circuit. A DC voltage from the detecting circuit is compared with a reference voltage from a reference voltage generating circuit by a comparing circuit. Based on a comparison output, the amount of attenuation of the variable attenuation circuit is controlled, and after the output of the variable attenuation circuit is amplified by an amplifier, it is mixed with a local oscillation signal from a local oscillation circuit at a mixer circuit, converted to a microwave signal, and transmitted.

Abstract: The level of an input high-frequency signal is adjusted by a transmission-level adjusting portion, and two signals are created and distributed by a distribution portion. One of the two signals is output, while the other one thereof is applied to a frequency-deviation adjusting portion to cancel the frequency property of a detection portion and thereafter is applied to the detection portion, where the signal is detected to be a DC voltage. A comparator compares the DC voltage with a reference voltage output from a reference voltage generating portion, and the output of the comparison is used to control a gain of the transmission-level adjusting portion.

Abstract: A DC voltage input through an input terminal is applied through an inductor, to a power supply circuit unit and an input voltage detecting circuit. The input voltage detecting circuit detects the input DC voltage and when it is detected that the input voltage value may possibly cause malfunction, a control circuit turns off a switch circuit based on the detection output, whereby power supply from the power supply circuit to a transmission circuit is stopped, and malfunction of the transmission circuit is prevented.

Abstract: A level detection circuit detects a signal level of an intermediate frequency signal which is superposed on a DC voltage input from an input terminal and is separately extracted by an input processing circuit, and converts the same into a corresponding DC voltage for output to a transmission output control circuit. The transmission output control circuit compares the DC voltage received from the level detection circuit with a reference voltage and determines whether the intermediate frequency signal is being input. When the transmission output control circuit determines that the intermediate frequency signal is not being input, a switch circuit cuts off the power from a power control circuit to a transmission amplifying circuit. As a result, the radio transmission apparatus can prevent wasteful power consumption and can suppress a noise and a communication error when the transmission of the intermediate frequency signal is not intended.

Abstract: A main microstrip line, one end of which has an input signal supplied thereto and other end of which outputs a signal, is formed on a substrate. Five sub-microstrip lines are made to intersect with the main microstrip line, and are disposed one by one such that their lengths from the intersections to their respective ends vary. The sub-microstrip lines are each formed in a generally rectangular shape with their line widths all formed to have the same prescribed length, and are disposed all at the same prescribed intervals and generally parallel to one another.

Abstract: A DC voltage input to an IF, DC input is applied to a switching regulator of a power supply circuit, a DC voltage necessary for driving a power amplifier is directly applied from the switching regulator to the power amplifier, the voltage from the switching regulator circuit is applied to a voltage converter circuit from which a negative voltage of 5V is generated and applied to the power amplifier and other circuit, a positive voltage of 5V is generated from a dropper regulator circuit and applied to the power amplifier and other circuits.

Abstract: A level detection circuit detects a signal level of an intermediate frequency signal which is superposed on a DC voltage input from an input terminal and is separately extracted by an input processing circuit, and converts the same into a corresponding DC voltage for output to a transmission output control circuit. The transmission output control circuit compares the DC voltage received from the level detection circuit with a reference voltage and determines whether the intermediate frequency signal is being input. When the transmission output control circuit determines that the intermediate frequency signal is not being input, a switch circuit cuts off the power from a power control circuit to a transmission amplifying circuit. As a result, the radio transmission apparatus can prevent wasteful power consumption and can suppress a noise and a communication error when the transmission of the intermediate frequency signal is not intended.

Abstract: In a feedback type oscillation circuit including a first microstrip line connected to a signal input terminal of a transistor, a second microstrip line connected to a signal output terminal of the transistor, and a dielectric resonator coupled with the microstrip lines at high frequency, the first and second microstrip lines are provided with patterns that are branched off from the respective microstrip lines, each at an arbitrary angle.

Abstract: A DC voltage input through an input terminal is applied through an inductor, to a power supply circuit unit and an input voltage detecting circuit. The input voltage detecting circuit detects the input DC voltage and when it is detected that the input voltage value may possibly cause malfunction, a control circuit turns off a switch circuit based on the detection output, whereby power supply from the power supply circuit to a transmission circuit is stopped, and malfunction of the transmission circuit is prevented.

Abstract: A main microstrip line, one end of which has an input signal supplied thereto and other end of which outputs a signal, is formed on a substrate. Five sub-microstrip lines are made to intersect with the main microstrip line, and are disposed one by one such that their lengths from the intersections to their respective ends vary. The sub-microstrip lines are each formed in a generally rectangular shape with their line widths all formed to have the same prescribed length, and are disposed all at the same prescribed intervals and generally parallel to one another.

Abstract: The level of an input high-frequency signal is adjusted by a transmission-level adjusting portion, and two signals are created and distributed by a distribution portion. One of the two signals is output, while the other one thereof is applied to a frequency-deviation adjusting portion to cancel the frequency property of a detection portion and thereafter is applied to the detection portion, where the signal is detected to be a DC voltage. A comparator compares the DC voltage with a reference voltage output from a reference voltage generating portion, and the output of the comparison is used to control a gain of the transmission-level adjusting portion.

Abstract: In a feedback type oscillation circuit including a first microstrip line connected to a signal input terminal of a transistor, a second microstrip line connected to a signal output terminal of the transistor, and a dielectric resonator coupled with the microstrip lines at high frequency, the first and second microstrip lines are provided with patterns that are branched off from the respective microstrip lines, each at an arbitrary angle.

Abstract: An input signal having an intermediate signal superposed on a DC voltage is applied to a variable attenuation circuit through an amplifier. An output of the variable attenuation circuit is detected by a detecting circuit. A DC voltage from the detecting circuit is compared with a reference voltage from a reference voltage generating circuit by a comparing circuit. Based on a comparison output, the amount of attenuation of the variable attenuation circuit is controlled, and after the output of the variable attenuation circuit is amplified by an amplifier, it is mixed with a local oscillation signal from a local oscillation circuit at a mixer circuit, converted to a microwave signal, and transmitted.

Abstract: A DC voltage input to an IF, DC input is applied to a switching regulator of a power supply circuit, a DC voltage necessary for driving a power amplifier is directly applied from the switching regulator to the power amplifier, the voltage from the switching regulator circuit is applied to a voltage converter circuit from which a negative voltage of 5V is generated and applied to the power amplifier and other circuit, a positive voltage of 5V is generated from a dropper regulator circuit and applied to the power amplifier and other circuits.