JPS5950619A - Automatic matching system of antenna circuit - Google Patents

Abstract

PURPOSE:To reproduce an accurate matching with a storage data in an RAM, by providing a means selecting an address of a CPU and the RAM in interlocking with a band switch of an antenna circuit matching device so as to save the trouble of the readjustment of the matching device required at each band switching of a transmitter. CONSTITUTION:The transmitter is connected to an input side of an antenna circuit matching device and an antenna is connected to an output. A switch SW2 interlocked with the band switch SW1 of this matching device is provided and a signal is inputted to an operating circuit of the CPU every time the switch SW2 is operated. The address of the CPU and the RAM is selected with the signal input, and an output voltage of an angle detector proportional to the angle of rotation is A/D-converted in interlocking with the matching device. Further, the output of the CPU controls servo motors M1, M2, the trouble of the readjustment of the matching device required at each band switching of the transmitter is saved, allowing to reproduce accurately the matching with a data stored in the RAM.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic tuning method for an antenna matching circuit of a radio transmitter.

The antenna matching circuit of a wireless transmitter plays an important role in efficiently transmitting transmission power to the antenna and in reducing streaky radiation such as harmonics.

Of these, the sharpness characteristic is largely determined by setting the design values of the circuit constants, but the power efficiency is largely determined by tuning adjustment.

The basic operation of an antenna matching circuit is an impedance matching device that matches both the line impedance on the input (transmitter) side and the line impedance on the output (antenna) side.

Furthermore, for the purpose of reducing harmonics, a pi-match circuit with a Ronos filter configuration is often used, in which an inductance is used as a series element and a capacitor is used as a parallel element. In order to match the input and output impedance of this π-match circuit at a specific frequency, it is necessary to adjust all elements, but in the HF band top frequency band, a coaxial cable with a characteristic impedance of 5oΩ or 75Ω is used. Because of this, the output impedance of the antenna and transmitter is also designed based on this. However, especially in antennas, it is impossible to change constants at any time, so the permissible frequency range is extremely narrow for both single-band antennas and multi-band antennas. Since the operating frequency width of one band is narrow in terms of the graphic frequency within the permissible communication pan P, the change in the constant of the matching box within the pan P is not very large.

Therefore, in general, the inductance of a π match circuit is determined by selecting the tap of the coil for each band using a switch, and fine matching is achieved by using V C (Variable Condenser) on the input and output sides.
ser). To check this matching, install a waterfall between the transmitter output and the antenna.
If the SWR is 3 or less, it can be used, but it is preferable to set it to 1.5 or less. When using an antenna matching device, adjust the transmitter in advance with a dummy load equal to the antenna impedance, then insert a matching device between the transmitter and the antenna, and match so that the SwR indication is the lowest. VC on the input side and output side of the device
All you have to do is adjust the SWR to about 1.5 or less. The operation is simple if only one VC is to be adjusted at that time, but since the two VCs interact with each other and affect the helmet, it takes some effort to find the optimal point.

However, as long as the transmitter and antenna do not change, this position will not change, so the scale is recorded and set each time the switch is made. Automatic tuning of the matching device has been desired in order to save the effort of operating the matching device every time a change is made.

The present invention works in conjunction with a band switch to
alProcessor Unit) RAM (Ra
In conjunction with the matching regulator, the output voltage of the angle detector, which is proportional to the rotation angle of the regulator, is converted into A/I (analog/digital) and sent to the CPU battery. means for converting the SWR instruction output of the SWR measurement circuit provided in the writer output circuit into the RAM backed up by A/l) and inputting it to the CPU, and when the selected RAM is blank, the CPU
The drive output of outputs the rotation direction in which the SWR value decreases, and
A means for holding the motor at the lowest position of the WR value, a means for storing the output data of the rotation angle detector of the regulator in the RAM of the CPU, and a means for storing the data in the RAM address selected by the hand switch. means for driving the serve motor in a direction in which the data value matches the data from the rotation angle detector of the regulator, and a SW of the matching weak output circuit.
An antenna circuit automatic matching system for a radio transmitter is characterized in that it is configured with means for checking whether the R value is within a predetermined range, and this will be described with reference to an illustrated embodiment of the present invention. Then, the upper half of the figure is a matching circuit with a π-match configuration and an SWR measurement circuit (5), and the series inductance L of the π-match has a tap for each band, and the band switch SW, ? Switching. The input side variable capacitor vC1 and the output side variable capacitor vC2 can be adjusted separately, and vCl has a motor M1 and a rotation angle detector VR1, VC,
Serve motor M! and the rotation angle detector VR2 are mechanically interlocked.

The lower half of the figure is a block diagram of only the parts related to this embodiment among the internal functions of the CPU, and the "band state" is detected by the rotation angle detectors VR1 and VB2. "Rotation angle detection voltage", SW
6 r SWR instruction value is inputted to the CPU, and the ``drive output'' of the serve motors M1 and M2 is output to the CPU. Naturally, these inputs and outputs are performed through the I10 port of the CPH, but since there are many types of CPUs whose details differ depending on the manufacturer, we will describe them here as common principles.

Here, regarding the SWR measurement circuit that monitors the degree of matching, most direct-reading SWR meters currently in use are standard (6). Although it is not suitable for automatic measurement, for example, it is possible to measure SWR regardless of the passing power using Utility Model Application No. 55-171428 and Utility Model Application No. 57-93873 r, which was previously filed by the present applicant. Since the value can be determined, there is no problem when implementing the present invention.

The operation of the circuit shown in the figure is as follows. (1) Connect the transmitter output to the input side of this matching box, and connect the antenna to the matching box output side. (2) Band switch - tune to the desired band. (3) When the transmitter is operated, the SWR measurement circuit
The WR value (usually larger) is input to the CPU. (
4) Serve motors M1 and M2 are equipped with the CPU and the above-mentioned SW.
Add drive output in the direction that the R value decreases.

Since this drive output is modified every time the CPU clocks, the SWR value can be matched to the minimum value in an extremely short time. The SWR value at that time is the specified value (for example, SWR=
1.5), the motor drive output is stopped and the angle detector VR1, ! is sent to the specified RAM address by the "band state" input. : Stores the output voltage data from VB2. (5) If the SVI/R value does not fall below the specified value, a warning of inconsistency can be displayed, but if the adjustment is corrected using the hand axis, and it still does not decrease, an inspection is required as an accident. . The RAM that stores the adjustment data is backed up by a battery, so it retains the data even if Kuyuanbao is stopped. Therefore, for subsequent use, the serve motor can immediately reproduce the initial matching state by comparing the data held in the RAM and the output of the adjustment detector. Of course, it is also possible to make corrections by referring to the SWR value at this time as well.

As described above, the antenna circuit automatic matching method of the present invention not only eliminates the trouble of readjusting the antenna matching device every time the transmitter band is switched, but also extremely quickly updates data stored in the RAM. It has the effect of reproducing accurate matching, and also has the ability to automatically correct for fluctuations related to the antenna, and has the extremely useful effect of being able to warn of abnormal operation. It is possible.

[Brief explanation of drawings]

The figure is a schematic diagram of an embodiment of the present invention. Patent applicant: Yaesu Musen Co., Ltd. (9) 9IA/+

Claims (1)

[Claims] CPH in conjunction with the band switch of the antenna circuit matching device
means for selecting the address of the RAM of the CPH; and means for converting the output voltage of the angle detector proportional to the rotation angle of the regulator in conjunction with the matching regulator and writing it into the RAM backed up by the battery of the CPH. , the server that adjusts the matching regulator? Means for supplying the output to drive the motor from the CPU and the waterfall instruction output of the optical measurement circuit provided in the matching box output circuit.
Means to convert and input to CPU and selected RAM
When is blank, the drive output of the CPH outputs the rotation direction in which the original value decreases, and the means to hold the motor at the lowest position of the original value and the output data of the rotation angle detector of the adjuster are stored in the CPH RAM. If data is stored at the address of the RAM selected by the band switch, the data is searched in the direction in which the data value and the data from the rotation angle detector of the adjuster match. An automatic antenna circuit matching method for a transmitter, characterized in that it comprises means for driving a motor and means for checking whether a waterfall value of a matching box output circuit is within a predetermined range.