JPS6080323A - Tuning control method of power amplifier section of transmitter - Google Patents

Abstract

PURPOSE:To execute adjusting operation of a variable element at all times within a stable region by using a pseudo antenna resistor for a load of an output circuit to apply a preset adjustment in advance before a radio wave is emitted actually from a transmitter. CONSTITUTION:The preset adjustment is conducted in advance by using the pseudo antenna resistor for the load of the output circuit before the radio wave is emitted actually from the transmitter. In the said preset adjustment, variable elements C10, C20 are changed over the entire variable range to apply the adjustment thereby measuring the tuning value of each variable element in the assembled frequency and measuring the stable operation region of the transmitter when each variable element is changed before and after the tuning value. The variable elements are corrected again so as to be matched to the input impedance of the antenna at the operation and since the variable range of the variable elements is limited to the stable operating region set previously at the preset adjustment, the matching circuit element is protected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling matching tuning of a constant variable circuit element (hereinafter abbreviated as variable element) of a power amplifier output circuit of a wireless communication transmitter, particularly an HF charging power transmitter. It is something.

The output circuit of the final stage power amplification section of this type of transmitter generally requires tuning with the power amplification tube, matching with load impedance such as an antenna, suppression of unnecessary wave output, etc.
It is connected to the antenna as a low-frequency mud wave circuit, and the circuit elements of the low-frequency P-wave circuit have their values adjusted to best suit the frequency range selected for use by the transmitter and the selected antenna. It is required to include a variable element for setting.

FIGS. 1(A) and 1(B) are examples of conventional transmitter output circuits (low-frequency P-wave circuits). is a variable inductor, C1° and C7° are vacuum variable capacitors, L is a fixed or variable inductor, and C, C2 are fixed and semi-fixed vacuum capacitors. In general, when a frequency to be used is specified, the antenna corresponding to that frequency is not used as a load at first, but the antenna's built-in resistance is used as a load on the output circuit, and the value of the variable element is adjusted to give the maximum output to this load resistance. do. Next, the specified antenna is connected and radio waves are emitted, but since the input impedance of the antenna is not necessarily a pure resistance like the antenna's built-in resistance, the variable element is readjusted for matching. In this adjustment, it is known that if the variable element is changed to an unstable range such as oscillation of the output circuit, the circuit element is often damaged.

FIG. 2 shows one of these measures, and the variable elements of this circuit are two parallel capacitors C, fl and C2Q. A small vacuum variable capacitor cs is connected to each of these variable capacitors in a series, and matching for the given load is first performed using large capacitances C1 and C2, and fine adjustments are made using each cs. This is a circuit configuration that performs the following steps.

However, in this circuit, the variable range of the small capacitance capacitor C8 is constant regardless of the frequency, so the change in capacitance is too small in low frequency bands, but the amount of change is too large in high frequency bands, causing the circuit to become unstable. The disadvantage is that it can sometimes reach

In order to solve these problems, the present invention provides a tuning control method for a power amplifying section of a transmitter that can always adjust a variable element within a stable region.

The present invention will be explained in detail below.

1 as a built-in (preset) frequency for normal transmitters.
Approximately 0 frequency is incorporated, and the frequency to be used is selected and switched depending on the time of day to enable wireless transmission with as high an S/N ratio as possible. ! In addition, the output circuit of the power amplifier tube has π
π-shaped circuits are often used, and it is known that π-shaped circuits are particularly suitable for high-power transmitters. [For example, for Shioka 2 stones; transmitter load automatic matching device using a π-type circuit.

[Refer to Research on International Communication (International Telegraph and Telephone Company) No. 32, page 51, June 19G2] Therefore, in the following explanation, the case of a π-type circuit will be explained as an example, but the π-type circuit in which the present invention is implemented is
The variable elements of the shaped circuit are C1o and C3 as shown in Figure 1(B).
Cs1d is not used only at ゜.

In the present invention, before actually emitting radio waves from the transmitter,
Perform preset adjustment in advance by using a body-worn antenna resistor as the output circuit load. In this preset adjustment,
Adjust the variable elements CIO and C20 by varying them over their entire variable range, measure the tuning value of each variable element at the built-in frequency, and transmit when each variable element is varied before and after the tuning value. Measure the stable operating area of the machine. The adjustment and measurement procedures used in the present invention will be explained later, but in general, when making preset adjustments, the power supply voltage of the output tube is appropriately lowered, and a bias resistor is installed to ensure that the bias is applied when the output tube oscillates. Do it like this. The presence or absence of abnormal conditions such as oscillation can be determined by, for example, changes in plate current,
For example, it is detected by a decrease in current, and a safety limit for the value of the variable element during adjustment operation is determined. Furthermore, once the preset adjustment is completed, the transmitter can be put into operation for actual use. During operation, adjust the position of the variable element to the value obtained by preset adjustment for the selected channel frequency, then switch the load to the antenna and readjust the variable element to match the input impedance of that antenna. However, since the variable range of the variable element is limited within the stable operation range previously set during preset adjustment, the matching circuit element-1 is protected.

Next, the method of the present invention will be explained in more detail.

FIG. 3 is an example diagram of a variable element control loop of an output circuit. The control loop when controlling the variable condenser C (or variable inductance L) as a variable element consists of a motor (M) 2 that is driven to change the value of the variable element and can be stopped suddenly, and the output shaft of the motor. Position data 3a from position detector 3 and 1 position detector 3, which detects the position in which the indicated value of the variable element is located within the variable range in conjunction with
> and a position controller 4 that controls the drive of the motor 2 based on the control signal 11C, forming a closed loop to control the values of the variable elements. In the present invention, this control operation is performed in two stages as described above. One is that when a preset channel frequency is set, the load is a resistance built into the antenna, and the variable element is adjusted to the set tuning position # for each channel frequency using a manual signal that will be explained later. The preset adjustment operation is to change the preset value by rotating it in the opposite direction.The other operation is to correct the VCN in order to match this preset value with the actual antenna impedance.This is called the operation operation, and this is also explained in Figure 5. Use manual signals to do so. In addition, as shown in Figure 1 (B),
When using two variable elements such as Cl01C20 controlled by a motor, two sets of the control loops of FIG. 3 are required.

FIG. 4 is a diagram showing an example of the configuration of the position controller 4 in FIG. 3. The position control S4 in the figure includes a microprocessor (CPU) 5, an input port door, an output port 8, a memory 6.10, and a position data display 9 as shown.

Among these, control signals 11 to 16 input to the input port VC
is a digital signal that corresponds to the control signal 1 in FIG.
c to control the feed motor 2. These control signals are input to the input port according to the flowchart of FIG. 5, which will be explained later. Reference numeral 11 indicates a mode signal that takes one of the two modes of adjustment and operation, 12 indicates a precent value memory request signal, 13 and 14 are input pins for limit value memory request signals, 15 for channel switching signals, and 16 for manual change (UP/DOWN) signals. The memory 10 is a memory for storing six preset positions for each grid channel, and the memory 10 is a variable range limit table memory for storing upper and lower limit data of the variable range of the variable element. Note that the memory 10 in particular is called a table memory because it holds input data as a table within the memory. Position detector 3'V
For example, a known rotary encoder that can generate the rotation angle of the motor 2 and the position information of the variable capacitor is used as C.

Next, the method of setting (value) of the variable element will be explained using the flowchart of the variable element position control program shown in Fig. 5, but for convenience of explanation, channel selection and variable element setting will first be explained using an actual example. Let me show you. In the case of the first preset frequency change or preset frequency change, the person in charge of adjustment performs the grid adjustment, stores the preset position of the variable element in the memory 6, and sets it above an appropriate value inside the actual limit value of the variable range.

The lower limit values are set and stored in the table memory 10Vc, respectively. Using an actual numerical example, -4MHz,
CH3-5MHz, CH4-6MHz.

CH5・7MHz, b) Position data A known rotary encoder is used for position detection, and the resolution is 1/1000.

It is a vacuum capacitor, and the 10 pF position is set to 000,
/\ Also, if we assume that the position of 1000pF is 999, and that it changes by 10 to 1000 pF in 50 rotations of the capacitor shaft due to the structure, then it becomes 360 x 50/1000218°, so motor 2 moves the axis of variable capacitor C. 18° times-, Nio 1 Jino, 710 yen! 1r to Shiseist
It's seven years old. In addition, if the variable element has a variable inductance of 01 to 10μH, the position of 01μH is set to 00
0, set lOμH position to 999, and rotate 10 times to 01
If it changes from to 10μH, 360°X 1
Since 0/1000 = 3.6°, when the variable inductance L is rotated by 36° by the motor 2, the position information changes by 1°.

Since 999 and 999 are the ends of the mechanical variable range of the variable element, there is a risk that the variable element may be damaged if overrun occurs due to an error in the variable element driving gear, etc. Therefore, position information below 20 and above 980 is set outside the safe rotation range (over-speed range), and is supported by the program described in the explanation of the flowchart in FIG. 5 to prevent further rotation. The method for setting the variable elements will be described below using the example defined above.

Furthermore, Fig. 6 is an example diagram of the frequency versus tuning position in the above example, and Fig. 7 is an example diagram of the stable operating region determined as described above for each preset channel. It shows.

Now, in the flow diagram of Figure 5, first step ■, ■
Input the channel switching signal 15 to the input port door to set the specified child (for example, ≠1), and set ≠1.
Perform matching adjustment for the designated frequency of the channel, 3 MHz. In the case of preset adjustment, in step 2, the mode signal 11 is sent to the input port door and the operation mode is set to "PA adjustment", thereby proceeding to the adjustment operation. In step 2, the maximum changeable range of the variable element is set to 0 to 999. When the actual change in the variable element IJ is set, the range is set to 20-980.

Next, data is written into the memory V in steps ① to ②.

Specifically, in step (2), the transmitter output stage is tuned at the preset frequency of channel 1 to determine the tuning position of the variable element. This tuning operation is generally performed by a manual signal 16' applied to the input port door.
/DOWN direction and give a drive signal to the motor 2 in the direction in which the output of the position detector increases/decreases accordingly.For example, the variable element is stopped at a tuned position that gives the maximum output to the load. do.

The tuned position is stored in the storage area of channel 1 of the position memory 6 from the input port door as the output digital signal 3a of the position detector 3 by applying the preset value memory request signal 12 to the input port door. Next, a stability test is performed to establish a stable operating area. During operation of the transmitter, in order to set a limit on the variable range so that the variable element cannot be changed outside of this stable area, the upper and lower limits of the variable element position in the stable operation area are set by the position detector 3, and these are By inputting the limit value memory request signal 13 and step 4 to the input port door with a value inside the limit value set as the set limit value, the variable range III l (is stored in the storage area of channel 1 of the U table memory 10).

In this way, after writing of the preset value and two limit values of channel 1 to memories 6 and 10 is completed, adjustment is made to channel 2, and the tuning position data of the variable element is transferred to the preset position memory in the same way as for channel 1. The upper and lower limit values set as described above by measuring the stable operating area are stored in the storage area of the address of channel 2 of variable range limit table memory 10.
storage area. In step (3), adjustments are made for all preset frequencies in the order of the channel numbers to be preset, and preset position data and data on the upper and lower limits of the variable range limit are stored in the storage area for each channel.

Once the preset operation is completed above, it is possible to proceed to the operational operation.

In the operational operation, the mode signal 11 to the input port is set to the operational mode, the antenna pseudo resistance at the time of presetting is switched to the designated antenna, and actual radio waves are emitted. Let's take the case of emitting lightning and waves on channel 1 as an example. When channel 1 is selected by sending the channel switching signal 15 to the input port door, the preset position data of the child 1 previously stored in the preset position memory 6 by Briseno) iEk is sent out as step 3 in the flow diagram. It compares it with the output data of the position detector 3, outputs the drive signal 4a to the drive motor 2 from the output port 8 at the points where the two match, and stops the drive of the variable element C at -dispersed points.

Next, in step (3) of the flow diagram, since the operation mode is determined to be the operation mode by the input of the signal 11,
Proceeding to step (2), the variable range limit value data of channel 1 stored in the variable range limit table memory 10 is read out to the microprocessor 5, and the motor drive signal to be output from the input port door to the output port 8 via the microprocessor 5 is set. Compared with the position signal from the detector 3, the K I is set so that the position of the variable element is kept within the variable range limit value.
Set the J limit value. In operation mode, radio waves are emitted from the specified antenna, but the input impedance of the antenna generally changes not only due to pure resistance such as the antenna pseudo-resistance, but also due to weather conditions, so steps are required to follow this change. Adjust the correction according to the conditions of the day in ~■. For that, input the manual signal 16 to the port door V
c-sending Similar to the description of step (2) above, a drive signal 4a with UP/DOWN directions is applied to the motor 2 to increase or decrease the variable element, and antenna matching is performed so that, for example, the transmitter output meter reaches its maximum output. At this time, the output of the position detector 3 is monitored so as not to accidentally change the variable element in the unstable operation region 1 and cause oscillation, etc., and when the position reaches the limit value, the drive signal from the microprocessor is is cut off and the motor is automatically stopped quickly. Knead is the step ■ and @.

In addition, the right side of ``What is the manual request?'' in step ■ in Figure 5, ``Ari→Nan change'', is a case where the manual request is no longer necessary because the value has been adjusted to the correct value, and it is not necessary to make a manual request in step @. to stop the motor.

Although the method of the present invention has been described in detail above, the variable element used in the power amplification section of a high-power transmitter is generally required to have a large power capacity, so the price per component is quite high. Therefore, the present invention has a great practical effect in that it protects these expensive elements and power amplifier tubes, and also eliminates the need to repair them when they are damaged, such as removing carbon that has adhered to the elements due to spark generation.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an example of the configuration of an output circuit of a conventional transmitter, Fig. 2 is a circuit diagram showing an example of a configuration of another output circuit, and Fig. 3 is a circuit diagram showing an example of the configuration of an output circuit of a conventional transmitter. FIG. 4 is a block diagram showing an example of the configuration of a position controller used in the present invention, FIG. 5 is an operation flow diagram showing an example of a position control program used in the present invention, and FIG. 6 is a block diagram showing an example of a position control program used in the present invention. 1 is a tuning frequency versus load position characteristic diagram of the output circuit, and FIG. 7 is a stable operating range characteristic diagram for each channel in the present invention. C, C+o, C2o- variable capacitor, ]... control signal, 2... motor (M), 3... position detector,
4...Position controller, 5・Microprocessor, 6・
...Preset position memory, 7...Input port,
8...Output port, 9...Position data display, 10
... Variable range limit table memory, 11... Mode (adjustment/operation) signal, 12... Preset value memory request signal, 13.14... Limit value memory request signal,
15...Channel switching signal, 16...Manual (UP/D OWN) signal. Patent applicant Kokusai Telegraph and Telephone Co., Ltd. Kokusai Denki Co., Ltd. Agent Hibaku Gakudo Tsuneo Hakusui

Claims (1)

[Claims] In a tuning control method of a power amplification section of a wireless communication transmitter, in which one of a plurality of preset channel frequencies is designated and tuning is automatically switched to the designated channel, The preset positions of each variable circuit element of the power amplification section and the upper and lower limit positions of the values of the variable elements at which the power amplification section of the transmitter must operate stably are determined, and the respective storage locations in the storage device are determined. The preset adjustment is stored for each channel in #, and the load is switched from the mounted antenna resistance to the specified antenna by channel specification, and each variable circuit element is automatically adjusted to the preset value of the specified channel stored in the storage device. After the adjustment, the transmitter performs a correction adjustment to correct the difference between the antenna impedance and the antenna mounting resistance so as not to exceed the upper and lower limit positions of the stable operation range stored in the memory device. Tuning control method for power and force amplification sections.