JPH0522161A - Transmission power controller - Google Patents

Abstract

PURPOSE:To correct the frequency characteristic of a filter at the transmitter of a car telephone or the like by utilizing an APC circuit. CONSTITUTION:DC voltages from a fixed voltage generating circuit 13, which receives power level information from a control part 1, and from a DC voltage generator 14 similarly receiving the frequency characteristic information of a filter 6 from the control part 1 are respectively added by an adder 15 and defined as the fixed voltage of an APC circuit 8. This fixed voltage is compared with a detected voltage, for which one part of an output from an amplifier part 4 is extracted by a directional coupler 5 and detected by a detecting diode 9, by a differential amplifier 10 and the APC control is executed until the difference is eliminated. Therefore, by applying data from the control part 1 to the DC voltage generator 14 so as to correct the frequency characteristic of the filter 6, as the output of the filter 6, the flat transmitting characteristic properly correcting the frequency characteristic can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide band transmission power control device used for automobile phones, mobile phones and the like.

[0002]

2. Description of the Related Art FIG. 2 shows the configuration of a conventional transmission power control device. In FIG. 2, 21 is a control unit (C
PU) and sends channel data to the PLL circuit 22. 23 is a VCO (voltage controlled oscillator)
It constitutes a part of the L circuit 22. Reference numeral 24 is an amplifier, the output of which is emitted into the air through a filter 26 and an antenna 27. Reference numeral 28 denotes an APC (automatic power control) circuit, which includes a directional coupler 25, a detection diode 29, a differential amplifier 30, a driver transistor 31, and a fixed voltage generating section 32. Fixed voltage generator 32
Is a fixed voltage generation circuit 33 that receives power control information from the control unit 21, and buffers 34 and D that monitor and exchange control voltage information of the PLL circuit 22.
It is composed of a C amplifier 35 and an adder 36 that adds the outputs of the fixed voltage generating circuit 33 and the DC amplifier 35.

Next, the operation of the above embodiment will be described.
Upon receiving the channel data from the control unit 21, the PLL circuit 22 generates a specific frequency together with the VCO 23. The relationship between the control voltage V1 of the PLL circuit 22 and the frequency at this time is shown in FIG. From this voltage V1, the buffer 34 and the DC amplifier 35 generate a voltage V2 in which the frequency characteristic of the filter 26 is corrected as shown in FIG. Then, this voltage V2 and the output voltage from the fixed voltage generation circuit 33 that matches the power level designated by the control unit 21 are added by the adder 36 to create a voltage V3, which is applied to one side of the differential amplifier 30. Input to the input terminal. The relationship between the voltage V3 and the frequency is shown in FIG.

As described above, in the above conventional example, the power level of the APC circuit 28 as a whole can be set higher as the frequency becomes higher, and the tendency that the passage loss increases as the frequency characteristic of the filter 26 becomes higher is corrected. can do.

[0005]

However, in the above-mentioned conventional transmission power control device, the characteristic of the filter 26 is as shown in FIG.
When the characteristic includes a ripple as shown in (4), there is a problem that it is not possible to perform an appropriate correction such as removing the ripple to make it flat.

The present invention solves such a conventional problem, and an object of the present invention is to provide an excellent transmission power control device capable of appropriately correcting the characteristics of a filter.

[0007]

According to the present invention, in order to achieve the above object, a means for obtaining a fixed voltage of an APC circuit is controlled according to a frequency characteristic of a filter under the control of a control section. And a means for generating a DC voltage.

[0008]

Therefore, according to the present invention, the optimum correction value for each frequency can be obtained by the APC circuit by previously inputting the APC voltage value for correcting the frequency characteristic of the filter into the control section. You can

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, reference numeral 1 is a control unit (CPU), which sends channel data to the PLL circuit 2. Three
Is a VCO and constitutes a part of the PLL circuit 2. Reference numeral 4 denotes an amplifier, the output of which is emitted through the filter 6 and the antenna 7 into the air. Reference numeral 8 denotes an APC circuit, which includes a directional coupler 5, a detection diode 9, a differential amplifier 10, a driver transistor 11, and a fixed voltage generator 12. The fixed voltage generation unit 12 receives the power level information from the control unit 1 and the fixed voltage generation circuit 1
3, a DC voltage generator 14 that similarly receives frequency information of the filter 6 from the control unit 1, and an adder 15.

Next, the operation of the above embodiment will be described.
When the PLL circuit 2 receives the channel data from the control unit 1, the PLL circuit 2 generates a specific frequency together with the VCO 3. The generated frequency is amplified by the amplifying unit 4, and then emitted into the air through the filter 6 and the antenna 7. A part of the transmission frequency amplified by the amplification unit 4 is taken out by the directional coupler 5 and rectified into a direct current by the detection diode 9,
The detected voltage is input to the differential amplifier 10. In the differential amplifier 10, the detection voltage passed through the detection diode 9 and
The fixed voltage from the fixed voltage generator 12 is compared, the difference between the two signals is input to the driver transistor 11, and APC control is performed until the difference disappears.

In the fixed voltage generation unit 12, the fixed voltage generation circuit 13 receives the power level information from the control unit 1 and generates a DC voltage according to the power level information. Further, the DC voltage generator 14 is provided with frequency information for correcting the frequency characteristic of the filter 6 stored in the control unit 11, and generates a DC voltage according to the frequency information. Then, the output voltages from the fixed voltage generation circuit 13 and the DC voltage generator 14 are respectively added by the adder 15, and the output voltage of the adder 15 becomes the fixed voltage of the APC circuit 8 and is input to the differential amplifier 10. To be done.

Thus, according to the above embodiment, the APC
A fixed voltage input to the differential amplifier 10 of the circuit 8 is controlled by the control unit 1 to generate a DC voltage according to the frequency characteristic of the filter 6, and a DC voltage generator 14 according to the power level information. Since the respective outputs from the fixed voltage generating circuit 13 that generates the DC voltage are added by the adder 15, the correction can be performed in consideration of the frequency characteristic of the filter 6.

In the above embodiment, the fixed voltage generator 12 for obtaining the fixed voltage input to the differential voltage amplifier 10 includes the fixed voltage generator circuit 13 and the DC voltage generator 14.
However, even if a single DC voltage generator that generates an appropriate DC voltage determined by both the frequency characteristic information of the filter 6 and the power level information is used, The same effect can be obtained.

[0014]

As is apparent from the above embodiment, the present invention allows the frequency characteristic of a wave filter including ripples and the like to be input in advance to the control section.
The fixed voltage of the APC circuit can be set to an appropriate value for each channel (frequency), and as a result, the output of the filter can have a flat frequency characteristic.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a transmission power control apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic block diagram of a conventional transmission power control device.

FIG. 3A is a diagram showing a frequency characteristic diagram of a control voltage in a PLL circuit of a conventional device, and FIG. 3B is a frequency characteristic diagram after voltage conversion of FIG. Frequency characteristic chart

FIG. 4 is a frequency characteristic diagram of a filter used in a conventional device.

[Explanation of symbols]

1 Control unit (CPU) 2 PLL circuit 3 VCO 4 amplifier 5 directional coupler 6 filter 7 antenna 8 APC circuit 9 Detection diode 10 Differential amplifier 11 Driver transistor 12 Fixed voltage generator 13 Fixed voltage generation circuit 14 DC voltage generator 15 adder

Claims (3)

[Claims] 1. A control unit for controlling a transmission frequency and a transmission power, a PLL circuit for generating a transmission wave, an amplification unit for power-amplifying the transmission wave, and a filter for filtering an unnecessary component of the transmission power. And a means for obtaining a fixed voltage to be input to the APC circuit, the DC voltage corresponding to the frequency characteristic of the filter under the control of the control unit. A transmission power control apparatus including means for generating 2. The means for obtaining a fixed voltage is D controlled according to the frequency characteristic of the filter under the control of the control section.
A DC voltage generator for generating a C voltage, a fixed voltage generation circuit for generating a DC voltage according to the power level information,
The transmission power control device according to claim 1, further comprising: an adder that adds outputs of the DC voltage generator and the fixed voltage generation circuit. 3. A means for obtaining a fixed voltage is an appropriate D determined by both the frequency characteristic information of the filter and the power level information under the control of the control section.
The transmission power control device according to claim 1, wherein the transmission power control device is one DC voltage generator that generates a C voltage.