JPH10112625A - Tracking circuit for matched tuner circuit of transmitter and tracking method for matched tuner circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a matched tuner circuit using the VSWR(voltage standing wave ratio) and also to provide a tracking method of the matched tuner circuit. SOLUTION: A matched tuner circuit 3 secures impedance matching between a transmission power amplifying part 1 and an antenna 5 by means of variable elements of a variable coil and/or a variable capacitor. Then a control (tracking) circuit of the circuit 3 consists of a CM wattmeter 11 which is placed at the output side of the part 1, a calculation comparison circuit 13 which calculates a VSWR from the traveling-wave voltage Vf and the reflected wave voltage Vr which are detected by the wattmeter 11 and also detects the change of the VSWR, and a variable element drive circuit 14 which drives the variable elements to increase or decrease the inductance or capacitance when the VSWR calculated by the circuit 13 is larger then the prescribed value. Then the circuit 14 is controlled by the output of the circuit 13, so that the VSWR is reduced less than the prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a matching tuning circuit tracking circuit and a matching tuning circuit tracking method for impedance matching between a transmission side and a load side when switching the frequency of a transmitter.

[0002]

2. Description of the Related Art A transmitter, particularly a short-wave transmitter, has a filter for reducing harmonics after a power amplifier, and a circuit for matching the impedance of the power amplifier and an antenna. Various matching tunings have been used to provide In addition, a short-wave transmitter usually has a plurality of frequencies with one transmitter, and switches the frequency according to operation time, area, application, and the like. Therefore, it is necessary to change the position of the matching tuning depending on the frequency. Matching tuning is performed using two variable elements. Also, when the antenna impedance changes during operation, it is necessary to automatically change the matching tuning point in order to always maintain the optimum matching tuning.

Conventionally, as shown in FIG. 6, a double pie circuit matching system comprising a power amplifying section 1, a load / phase error detecting circuit 2, capacitors C1, C2, C3 and variable coils L1, L2 as shown in FIG. Tuning circuit 3, variable coil L1,
Motors 4a and 4b for variably driving L2, an antenna 5,
The load error (V) detected by the load / phase error detection circuit 2
z) A / D converters 6b, 6a for tracking the matching tuning circuit 3 based on the phase error (Vφ) and a CPU 8 having driving circuits 7a, 7b for the motors 4a, 4b. Was used. The tracking operation in this circuit configuration is such that the load error (Vz) and the phase error (Vφ) detected by the load / phase error detection circuit 2 are A / D
The signals are converted into digital signals by the converters 6b and 6a, and the polarity and threshold value are processed and determined by the CPU 8, and the variable portions of the variable coils L1 and L2 are driven to perform matching tuning. In addition,
In the actual circuit, the capacitors C1, C2, and C3 are switched and used for each band by a changeover switch (not shown).
The variable coil L1 tracks the phase error, and the variable coil L2 tracks the load error.

That is, the general operation of this circuit is to simulate the impedance at the input point A of the matching tuning circuit, and determine whether the impedance is higher or lower than a specified impedance (Z = Rs + jXs), and whether it is inductive or capacitive. (Vz, Vφ), and moving the two variable elements (two variable coils or two variable capacitors, or a combination of a variable coil and a variable capacitor) in accordance with a predetermined algorithm that is a signal thereof, performs matching tuning. Was taking. Therefore, in the double pie circuit of this example, the variable coil L1 is increased in the case of inductiveness, the variable coil L1 is adjusted in the case of capacitive, and the variable coil L2 is decreased in the case of higher than the specified impedance. Conversely, if low, variable coil L
Adjust 2 more. Using these algorithms, the load impedance (antenna impedance) is automatically followed even during operation.

[0005]

However, in this conventional method, it is necessary for the matching tuning circuit 3 to change the algorithm for each of various circuit systems such as a pie circuit, a double pie circuit, and a T circuit. Also, if the load changes greatly and deviates significantly from the alignment point, the algorithm does not match, and the automatic tracking may diverge. Further, in the conventional method, the range of automatic tracking (automatic tuning / matching) due to load fluctuation and the automatic correction from the preset is narrow, and the diverging region, that is, the convergence is obtained even when the variable elements are alternately moved according to a predetermined algorithm. In this case, a phenomenon in which the variable element runs away and the variable element runs away has occurred. It is also necessary to change the algorithm depending on the circuit system. SUMMARY OF THE INVENTION The present invention solves such problems of the prior art, and provides a matching tuning circuit using a VSWR (voltage standing wave ratio) and a tracking method in the matching tuning circuit.

[0006]

A tracking circuit of a matching tuning circuit of a transmitter according to the present invention includes at least two variable coils and / or variable impedance matching between a transmission power amplifier and an antenna.
Alternatively, in a tracking circuit of a matching tuning circuit performed using a variable element of a variable capacitor, a CM power meter provided on an output side of the transmission power amplifier, a traveling wave voltage and a reflected wave voltage detected by the CM power meter. And a calculation and comparison circuit for detecting a change in the voltage standing wave ratio from the voltage standing wave ratio, and when the voltage standing wave ratio obtained by the calculation and comparison circuit is larger than a predetermined value. A variable element driving circuit that drives each of the variable elements to increase or decrease the inductance or capacitance thereof, and that the output of the calculation and comparison circuit controls the voltage standing wave ratio to be equal to or less than a predetermined value. The variable element driving circuit is controlled.

The tracking method of the matching tuning circuit of the transmitter according to the present invention is a method of matching tuning in which the impedance of the transmission power amplifying unit and the antenna is matched using at least two variable coils and / or variable elements of variable capacitors. In the tracking method, a voltage standing wave ratio is determined from a CM power meter provided on the output side of the transmission power amplifier and a traveling wave voltage and a reflected wave voltage detected by the CM power meter, and the voltage standing wave ratio is determined. If the wave ratio is larger than a predetermined value, the inductance or capacitance of one of the variable elements is increased by a predetermined step width until the voltage standing wave ratio passes through a minimum value point. Means for decreasing, and increasing or decreasing the inductance or capacitance of the other one of the variable elements by a predetermined step width until the voltage standing wave ratio passes a minimum value point. Means for causing the one variable element and the other variable element to alternately form a loop for increasing and decreasing the inductance or capacitance until the voltage standing wave ratio passes a minimum value point, This loop is repeatedly operated until the voltage standing wave ratio becomes smaller than a predetermined value.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a tracking circuit of a matching tuning circuit having a double pie circuit configuration of a transmitter, which is performed by using a VSWR (voltage standing wave ratio). An error signal for operating each variable element is Vf (traveling wave voltage),
This signal is detected as a Vr (reflected wave voltage) signal, and the detected signal (Vf, Vr) is composed of an A / D converter 12, a calculation comparison circuit 13 of the VSWR, a CPU 15 having a drive circuit 14 of the motors 4a, 4b, and the like. ing. This tracking circuit calculates the VSWR from Vf and Vr detected by the CM power meter 11.
Is calculated and compared with a predetermined specified value (threshold). The drive circuit 14 changes the inductances of the variable coils L1 and L2 so as to fall below the specified value, thereby achieving matching tuning. .

The tracking method of the matching tuning in this tracking circuit is performed by forcibly driving the variable coils L1 and L2 alternately on the basis of the calculated value of the VSWR and slightly driving the variable coils L1 and L2 in the increasing and decreasing directions by a predetermined step width. VSWR
Is compared with the VSWR measured immediately before, and the repetition follows the minimum value point of the VSWR. 2 and 3 are flowcharts of an embodiment of the tracking method using the VSWR of the present invention. When the output of the transmitter is output, the VSWR is always monitored, and the VSWR is equal to or greater than a specified value (in this example, 1.1 or more). ), The tracking operation is started. If the VSWR is deteriorated beyond a certain reference value (2.0 in this example), the tracking operation is started after the output is reduced. Next, setting of the width (coil step width) of the inductance of the variable coils L1 and L2, which are variable elements, changes every step (coil step width) is performed by coarse tuning (step width is coarse) at the time of the first tracking. Every time the number of times is increased, the step width is densely (narrowed) to improve the efficiency of the tracking time. In addition,
These are the cases where a stepping motor is used as the motor of the variable element, and the motor speed may be changed for a normal motor.

Next, one of the variable coils L1 and L2 is forcibly moved in a direction in which the inductance increases or decreases (in the case of a capacitor, the capacitance increases or decreases) by a predetermined step width. In this embodiment, in the first variable coil L1 reduction stage, the variable coil L1 is moved by one step in the decreasing direction,
The VSWR before and after the reduction operation is compared, and when the VSWR becomes worse, the process proceeds to the next variable coil L2 reduction stage. When the VSWR is improved, the VSWR is further moved in the same direction by a predetermined step width, and each time the VSWR is changed.
And this operation is repeated until the measured value after the change becomes worse in the comparison before and after the VSWR. Then, when it becomes worse, that is, when the minimum value of VSWR is found, the process proceeds to the next variable coil L2 reduction stage. If the added value of the VSWR falls within a specified value (1.05 in this example) during this operation, the process exits the loop and makes an output determination.

In the next variable coil L2 reduction stage, similarly to the variable coil L1 reduction, the inductance of the variable coil L2 is reduced by a predetermined step width, and when the minimum value of the VSWR is found, the process proceeds to the next L1 increase stage. Thus, L
After passing through the stage of 1 decrease → L2 decrease → L1 increase → L2 increase, as described above, the step width is made narrower than the first time, and the minimum value of the VSWR is searched on the same route. VS by the above method
When the added value of WR falls within the specified value (1.05 in this example), the process exits the loop and proceeds to the output high / low determination flow. If the output determination is low, the process returns to the VSWR minimum point search loop again. Return. If the output determination is high, the tracking operation is completed. If the VSWR search route cannot be exited for some reason, the number of times is counted, and if the count exceeds a specified value (20 times in this example), an alarm (ALM) is issued and processing such as stopping the transmitter is performed. I do. In the flowcharts of FIGS. 2 and 3, VS represents the VSWR value at the time of measurement, and S1 represents the VSWR value immediately before being changed to VS. The order of increasing and decreasing the inductance of each of the variable coils L1 and L2 can be arbitrarily determined.

FIGS. 4 and 5 are detailed flowcharts of the VSWR tracking flowchart of the double pie circuit shown in FIGS. 2 and 3. Hereinafter, this example will be described. First, conditions are set, and the calculation of VSWR is SWR simple calculation, that is, SWR = (Vf + Vr) / (Vf-Vr).
For the determination of the tracking operation, for example, if the VSWR is 1.1 or more, the tracking operation is started. In the high / low control of the output, for example, when the VSWR is 2.0 or more, the output is reduced to less than 2.0. The initial step width K of the variable coils L1 and L2, the prescribed values (target value of addition) S and VS of the VSWR
The initial value S1 of the WR is determined. For example, K = 0.05 μH, S
= 1.01, S1 = VS (VSWR). Variable coil L
The step width of 1 and L2 is made dense (narrow) for each loop number (N), for example, K / N.

Next, in the L1 reduction stage, the inductance of the coil L1 is reduced by the initially set coarse coil step width, and the VSWR value calculated at this time, that is, VS, is stored as the VSWR value before the change. Compare with If VS is less than or equal to the specified value S, the process exits the loop and enters the determination of the output high and low. If the output is high, the tracking operation is completed. If VS is equal to or greater than the specified value S, the value is compared with the initial value S1, and if VS is larger (bad) than S1, the process goes to the next L2 reduction stage. Also, VS is S1
If it is smaller (better), it will be L within the L1 reduction stage.
The value of VS is compared with the previous value S1 at each step.
If VS becomes larger (bad) than S1 in the process, the next L
2 Go to the reduction stage. At this time, in this embodiment, the stage is returned to the state before the inductance of the coil L1 is deteriorated by one step, and the operation is shifted to the L2 reduction stage.

In the L2 reduction stage, as in the L1 reduction stage, the inductance of the coil L2 is reduced with a coarse coil step width, and the calculated VS and the added value S are calculated.
Then, it is determined whether or not to go to the output determination. If VS <S, the output determination is made. If the output is high, the tracking operation is completed. If VS> S, then VS is compared with S1 to determine whether to repeat the decrease in L2 or to go to the next L1 increase stage. If the result of the comparison between VS and S1 is VS> S1, the process proceeds to the next L1 increase stage. In the L1 increase stage, the inductance of the coil L1 is increased with a coarse coil step width similarly to the previous stage, and the calculated VS is compared with the specified value S, and the output is determined in the same manner as the L1 decrease stage. Is determined, and if output determination is not possible, VS is compared with S1, and it is determined whether to repeat the increase in L1 or to go to the next L2 increase stage. If the comparison result between VS and S1 is VS> S1, the process proceeds to the next L2 increase stage.

In the stage of increasing L2, the coil L2 is
The inductance is increased with a coarse coil step width, the calculated VS is compared with a specified value S, and it is determined whether or not to perform output determination as in the L1 increase stage. If output determination cannot be performed, VS and S1 And it is determined whether to repeat the increase of L2 or to return to the first L1 decrease stage of the loop. If the comparison result is VS> S1, the process returns to the L1 reduction stage and enters the second loop. At this time, the coil step width at the time of increasing or decreasing the inductance in each stage is narrower than the first, as described above. Let V be a coil step width like K / 2
S is calculated, the specified value S and the stored previous VSW
A comparison is made with S1, which is R, and the same operation as in the first loop is performed. VS at each stage of this second loop
If <S is not satisfied, the coil step width at the time of increasing or decreasing the inductance is further reduced, for example, a coil step width such as K / 3 is entered, and the process enters the third loop.

Thereafter, the same loop operation is repeated, and VS <
It is continued until it becomes S. However, if the number of loops exceeds a predetermined number (20 in this example), the tracking operation is forcibly terminated and an alarm (ALM) is issued. In the above-described embodiment, the variable coils L1 and L2 as variable elements are respectively operated after being decreased, and then increased. However, the operation order of the variable coils L1 and L2 and the order of increasing and decreasing the inductance thereof are different in this embodiment. The order is not limited to this, and may be in any order. Although an example using a variable coil as the variable element is shown, a variable capacitor may be used.

[0017]

As described above, according to the present invention, even if the matching tuning circuit has a different circuit type such as a pie circuit, a double pie circuit, a T circuit, etc., the automatic tracking and automatic tuning algorithm (normally It is not necessary to change the software program in the device), and the CM power meter used for the output of the transmitter can be used for the error detector for automatic tracking and automatic tuning. Is played.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of an embodiment of a tracking circuit of a matching / tuning circuit of a transmitter according to the present invention.

FIG. 2 is a part of a flowchart illustrating a method of tracking a matching / tuning circuit of a transmitter according to the present invention, which is combined with FIG. 3;

FIG. 3 is a part of a flowchart illustrating a method of tracking a matching / tuning circuit of a transmitter according to the present invention, which is combined with FIG. 2;

FIG. 4 is a part of a flowchart illustrating details of a tracking method of a matching / tuning circuit of a transmitter according to the present invention, which is combined with FIG. 5;

FIG. 5 is a part of a flowchart illustrating details of a tracking method of the matching / tuning circuit of the transmitter according to the present invention, which is combined with FIG. 4;

FIG. 6 is a block circuit diagram of an example of a tracking circuit of a conventional matching / tuning circuit of a transmitter.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 power amplification unit 2 load / phase error detector 3 matching tuning circuit 4 a, 4 b motor 5 antenna 6 a, 6 b, 12 A / D converter 7 a, 7 b, 14 drive control circuit 8, 15 CPU 11 CM power meter 13 VSWS calculation・ Comparison circuit

Claims (4)

[Claims] 1. A tracking circuit of a matching tuning circuit for performing impedance matching between a transmission power amplification unit and an antenna using at least two variable coils and / or variable elements of a variable capacitor. A CM wattmeter provided on the output side, and a calculation comparison for obtaining a voltage standing wave ratio from the traveling wave voltage and the reflected wave voltage detected by the CM wattmeter and detecting a change in the voltage standing wave ratio And a variable element driving circuit that drives each of the variable elements to increase or decrease its inductance or capacitance when the voltage standing wave ratio obtained by the calculation and comparison circuit is larger than a predetermined value. The variable element drive circuit is controlled by an output of the calculation and comparison circuit so that the voltage standing wave ratio is equal to or less than a predetermined value. Tracking circuit of the matching tuning circuit of the transmitter to be butterflies. 2. A tracking method for matching tuning in which impedance matching between a transmission power amplifier and an antenna is performed using at least two variable elements of a variable coil and / or a variable capacitor. A voltage standing wave ratio is determined from a CM power meter provided on the side and a traveling wave voltage and a reflected wave voltage detected by the CM power meter, and when the voltage standing wave ratio is larger than a predetermined value. Means for increasing and decreasing the inductance or capacitance of one of the variable elements at a predetermined step width until the voltage standing wave ratio passes a minimum value point; and Means for increasing and decreasing the inductance or capacitance at a predetermined step width until the voltage standing wave ratio passes a minimum value point in the other variable element, The loop increasing and decreasing the inductance or capacitance to a position where the voltage standing wave ratio alternating with the other variable element passes through the minimum point is formed as,
A method for tracking a matching tuning circuit of a transmitter, wherein the loop is repeatedly operated until the voltage standing wave ratio becomes smaller than a predetermined value. 3. A matching tuning circuit for a transmitter according to claim 2, wherein the step width for changing the inductance or capacitance of said variable element is made coarse at first, and is gradually increased each time the number of loops is repeated. Tracking method. 4. A loop in which the one variable element and the other variable element are alternately increased and decreased in inductance or capacitance until the voltage standing wave ratio passes a minimum value point is repeated a predetermined number of times. 4. The tracking method of a matching tuning circuit of a transmitter according to claim 2, wherein the tracking operation is forcibly terminated when the voltage standing wave ratio does not become smaller than a predetermined value.