JP2627059B2 - Antenna tuner control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for an antenna tuner in a radio communication device.

[0002]

2. Description of the Related Art In a conventional antenna tuner of this type, as shown in FIG. 6, a voltage component is extracted from a midway between a transmitter (TX) and an antenna (ANT) via capacitors (C1, C2). Further, the current component is extracted by the coil (L), the resistance component is detected based on the amplitude difference between the voltage component and the current component (hereinafter, simply referred to as Z), and the L and C components are determined based on the phase difference. (Hereinafter, simply referred to as φ).

On the other hand, the coil (L) and the capacitors (C1, C2) of this detection circuit are not ideal, but actually, due to the stray capacitance (C0) or residual inductance (L0) as shown in FIG. Since the output voltage and the output current are not constant with respect to the frequency but cause an error, the Z
And SWR (Standin) by changing the coil and capacitor of the matching section based on
g Wave Ratio) = 1.0 (see FIGS. 8, 9 and 10).

[0004]

However, in the above-described prior art, since the Z and φ information are not constant with respect to a change in frequency, the ideal position of SWR = 1.0 is actually the same. Higher than that.

For this reason, even if the detection circuit shows a perfect matching state, the actual matching section is in an incomplete state, and the SWR deteriorates.

The present invention has been made for the purpose of improving such a drawback of a conventionally known antenna tuner.

[0007]

As means for achieving the above object, in the antenna tuner control method according to the present invention, frequency information of a transmission output is inputted to a storage control means, and the transmission output is inputted to a load impedance detecting means. And input the measurement data information of the load impedance detecting means to the storage control means.

Then, based on the frequency information of the transmission output,
The correction data information of the frequency characteristic in the load impedance detection means is stored in the storage control means in advance.

Next, by operating the impedance matching means, the measurement data information from the load impedance detection means can be corrected by the correction data information of the storage control means.

[0010]

The transmission output φ and Z information is stored in the storage control means in advance, and when the impedance of the transmission output and the load impedance are in a mismatched state, the correction data information based on the frequency information of the transmission output is used. The impedance matching means operates to prevent the above-mentioned mismatch state from occurring.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a control method of an antenna tuner according to the present invention will be described with reference to the drawings. FIG. 1 shows a software part of a storage control means (hereinafter referred to as a CPU) 5;
FIG. 2 and FIG. 3 each show a hardware portion composed of a transmitter 1, a φ, Z detector 2, a switch 3, and a matching circuit 4. FIGS.
It is a flowchart of a control program of a detection circuit frequency characteristic correction process and a tuning process.

P1... P10 in FIG. 2 and S in FIG.
1... S13 indicate the respective steps in the respective flowcharts, and the corresponding portions are indicated in parentheses in the text.

In the configuration shown in FIG. 1, an ideal antenna or dummy load is connected to the output side of the switch 3 in advance, and the switch 3 is set to the through side, and the transmission frequency data is input to the CPU 5 ( P3).

Next, in this state, the output of the transmitter 1 is changed to φ, Z
The data is input to the detector 2, and the output φ and Z data is input to the CPU 5 (P4, P7). At this time,
The difference from the ideal value is calculated (P5, P8) and further stored as correction data in the CPU 5 (P6, P9).
).

Thereafter, the same processing is performed by changing the frequency of the transmitter 1, but continues from the lower limit to the upper limit of the variable range of the frequency.

Note that the measurement accuracy increases as the number of points to be measured increases. For this reason, it is necessary to increase the capacity of the memory for correction data, and it is necessary to determine the correction error in consideration of the allowable range of the measurement error. is there.

On the other hand, before starting the tuning operation,
The transmission frequency data of the transmitter 1 is input to the CPU 5 in advance (S3), and correction data of φ and Z for this frequency is searched (S5, S6).

However, the switch 3 at this time is switched to the through side (S4).

Next, the switch 3 is switched to the matching circuit 4 (S7). When the output of the transmitter 1 is supplied to the matching circuit 4, depending on the state of the load on the antenna side, φ
And Z information are input to the CPU 5 by the φ, Z detector 2.

On the other hand, after adding the φ and Z information and their correction data (S8, S9), the load impedance is judged (S11, S12). If the matching state between the load and the transmitter is perfect, Although the impedance conversion by the matching circuit 4 is not performed (S13), if the matching state is incomplete, the impedance conversion by the matching circuit 4 is performed (S10).

Next, the operation of the LC circuit in the matching circuit 4 will be described. Based on the corrected φ and Z data, the zone on the Smith chart of FIG. 4 is determined (for example, point A). , The variable condenser of FIG. 5 (CT: T
The operation is performed by determining the rotation direction of the UNE side and CL: the LOAD side (however, L: the coil is assumed to be a constant value) and approaching the Z axis while crossing the φ axis in Fig. 4 alternately. .

When the transmission frequency is changed, it is necessary to search for each correction data again, and then perform a tuning operation after performing an addition process.

[0023]

As described above, the present invention can reduce the detection error caused by the influence of the stray capacitance of the components and the residual inductance, so that the impedance matching between the antenna and the transmitter can be accurately performed. This provides an excellent effect not found in the prior art.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a hardware portion as an embodiment of the present invention.

FIG. 2 is a flowchart of a software portion (φ, Z detection circuit frequency characteristic correction processing) according to the present invention.

FIG. 3 is a flowchart of a software portion (tuning process) according to the present invention.

FIG. 4 is a diagram showing positions of correction data according to the present invention.

FIG. 5 is an explanatory diagram of a circuit as an embodiment of the present invention.

FIG. 6 is a configuration diagram of a detection circuit in a conventional antenna tuner.

FIG. 7 is an explanatory diagram of each element in the LC circuit.

FIG. 8 is a graph showing an output voltage characteristic with respect to a phase difference in the phase detection circuit.

FIG. 9 is an impedance chart in which the X-axis is for resistance and the Y-axis is for phase difference (L-C). The intersection of the X and Y axes represents the point where SWR = 1.0, and the broken line is an example of the actual value.

FIG. 10 is a graph showing a frequency characteristic of a phase error output in the phase detection circuit, wherein a broken line is an example of an ideal value and a solid line is an example of an actual value.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmitter 2 φ, Z detector 3 Switch 4 Matching circuit 5 CPU

Claims (1)

(57) [Claims] A storage control means for storing measurement data information from a load impedance detecting means ; and an impedance matching means comprising an inductance component and a capacitance component .
An antenna tuner configured to select a switching circuit or a through circuit , wherein correction data information of frequency characteristics in the load impedance detection means is stored in the storage control means in advance, and a tuning operation of the impedance matching means is performed. Sometimes, if the measured data information from the load impedance detecting means is not the optimal value, the through circuit
Is switched to a matching circuit, and the measurement data information of the load impedance detection means and the correction data of the storage control means are changed.
Matching with the impedance matching means based on the
Cormorants control scheme of the antenna tuner, characterized in that.