JPH1198030A - Trasmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmitter which can accurately detect the electric power at the working frequency and also can suppress the undesired radiation. SOLUTION: This transmitter has a power amplifier part 2 which amplifies the output signals of a transmission part 1 and a directional coupler 4 which extracts some of output signals of the part 2. Then a BPF 9 is added to transmit the band signal of the working frequency among those signals which are extracted by the coupler 4 together with a 1st detection means 11 which detects the electric power of the working frequency signal, a band rejection filter 10 which rejects the band signal of the working frequency, a 2nd detection means 12 which detects the undesired radiation power, an a control part 14 which controls the levels of output signals of the part 1 in response to the electric power that are detected by both detection means 11 and 12 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a transmitter such as a wireless device, and more particularly to a control circuit for controlling transmission power of the transmitter.

[0002]

2. Description of the Related Art Hitherto, the extraction of traveling wave power in a transmission power amplifier of a radio device has used a directional coupling line.
Hereinafter, an example of a conventional wireless transmitter will be described with reference to FIG. In FIG. 2, the output of the transmission unit 1 is amplified to a predetermined power by the power amplification unit 2, supplied to the resonance inductor 5 via the LPF 3, and output from the antenna 7. Also,
The traveling wave coupling line 6 in the directional coupler 4 includes a terminating resistor 8.
And the detection circuit 15, the traveling wave component of the transmission output is detected by the detection circuit 15, and the control circuit 14 controls the output of the transmission unit 1 based on the detection signal.

[0003]

In the above-described conventional transmitter, when the traveling wave power is detected by the directional coupling line, the power of the unnecessary radiation signal is used as a part of the power of the frequency to be used. Therefore, there was a problem that accurate detection could not be performed. The present invention solves this problem, and enables accurate power detection at the operating frequency, and reduces transmission output power when an unnecessary radiation component of a predetermined level or more is detected,
It is an object of the present invention to provide a transmitter capable of suppressing unnecessary radiation.

[0004]

In order to achieve the above object, the present invention provides a band pass filter for passing a band signal of a predetermined frequency at an output stage of a traveling wave coupling line, and an output of the band pass filter. First detection means for detecting the power of the signal (power of the used frequency signal), a band elimination filter for removing a band signal of a predetermined frequency, and power of an output signal of the band elimination filter (power of an unnecessary radiation signal). And a control section for controlling an output signal level of the transmission section according to each power detected by the first and second detection sections. Then, when the unnecessary radiation power detected by the second detection means is lower than a predetermined value, the output signal level of the transmission unit is controlled according to the power of the working frequency signal detected by the first detection means, When the unnecessary radiation power is equal to or more than a predetermined value, the output signal level of the transmitting unit is reduced according to the unnecessary radiation power. As a result, it is possible to realize a transmitter capable of accurately detecting power at a frequency to be used and preventing transmission of unnecessary radiation outside the standard.

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be described with reference to FIG. In FIG. 1, an output signal of a transmission unit 1 is amplified to a predetermined power by a power amplification unit 2,
The signal is output from the antenna 7 via F3 and the resonance inductor 5 in the directional coupler 4. On the other hand, the traveling wave coupling line 6 in the directional coupler 4 includes a terminating resistor 7, a band-pass filter 9 for passing a band signal of a predetermined frequency to be used, and a band elimination filter 10 for removing a band signal of a predetermined frequency to be used.
Connected to. The power of the used frequency signal that has passed through the band-pass filter 9 is detected by the detection circuit (1) 11, and the detection output is supplied to the control circuit 14, and the output signal level of the transmission unit 1 is controlled according to the detected power. Is done. Further, the power of the unnecessary radiation component of the transmission signal that has passed through the band elimination filter 10 is detected by the detection circuit (2) 12, and the detection output is supplied to the control circuit 14 via the power variable circuit 13; Thus, the output signal level of the transmission unit 1 is controlled.

For example, when the unnecessary radiation power detected by the detection circuit (2) 12 is lower than a predetermined value, the control signal is not output from the output power variable circuit 13 to the control circuit 14, and the control circuit 14 (1) The output signal level of the transmission unit 1 is controlled so that the transmission power becomes a specified value only in accordance with the power of the used frequency signal detected in 11.
On the other hand, when the unnecessary radiated power detected by the detection circuit (2) 12 is equal to or more than a predetermined value, a predetermined control signal is output from the output power variable circuit 13 to the control circuit 14, and the control circuit 14 2) In accordance with the unnecessary radiation power detected in 12, control is performed so as to lower the output signal level of the transmitting unit 1 so that the unnecessary radiation power becomes lower than a predetermined value. With this configuration, it is possible to accurately detect the power of the used frequency band signal, and to suppress the unnecessary radiation level.

[0007]

According to the present invention, a transmitter capable of accurately detecting the power in the used frequency band and minimizing the transmission of unnecessary radiation outside the used frequency band can be realized, and the effect is remarkable. is there. In addition, since the configuration of the present invention is extremely simple, the present invention is economical and has a wide range of application.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a conventional wireless transmitter.

[Explanation of symbols]

1: transmission unit, 2: power amplification unit, 3: LPF, 4: directional coupler, 5: resonance inductor, 6: traveling wave coupling loop, 7: antenna, 8: termination resistor, 9: band-pass filter, 10: band removal filter, 11: detection circuit (1), 12: detection circuit (2), 13: output power variable circuit, 14: control circuit, 15: detection circuit.

Claims (2)

[Claims] 1. A transmitting unit, a power amplifying unit for amplifying an output signal of the transmitting unit, an extracting unit for extracting a part of an output signal of the power amplifying unit, and detecting a power of the extracted signal. In a transmitter including a detection unit and a control unit for controlling an output signal level of the transmission unit according to the detected power, a band of a predetermined frequency in the extracted signal is provided to an output stage of the extraction unit. A band-pass filter for passing the signal;
First detection means connected to the band-pass filter for detecting the power of the band signal of the predetermined frequency, a band elimination filter for removing the band signal of the predetermined frequency from the extracted signals, and the band elimination filter A second detection unit connected to the second detection unit for detecting the power of the unnecessary radiation signal; and a control unit for controlling an output signal level of the transmission unit according to each of the powers detected by the first and second detection units. A transmitter comprising: 2. The transmitter according to claim 1, wherein the control unit detects the unnecessary radiation power detected by the second detection unit when the unnecessary radiation power is lower than a predetermined value. Controlling the output signal level of the transmitting unit in accordance with the power of the band signal of the predetermined frequency; and when the unnecessary radiation power detected by the second detection means is equal to or more than a predetermined value, the transmission is performed in accordance with the unnecessary radiation power. A transmitter configured to reduce the output signal level of the unit.