JPS60220873A - Swr meter - Google Patents

Abstract

PURPOSE:To prevent the destruction of a diode for detection due to overvoltage by leading out a detecting voltage of a wave reflected from an antenna and using as the ALC control voltage of a transmitter. CONSTITUTION:The output voltage of the reflected wave detection diode 45 is applied to an input 47a of a voltage comparator 47, then an output voltage 47c is outputted when the applied voltage exceeds a set value 47b. This voltage 47c is applied to the ALC terminal 19 of the transmitter and used as the ALC control voltage. Consequently, the transmission output decreases and the diode 45 is prevented from being destroyed.

Description

[Detailed Description of the Invention] This invention provides an 8WR
The purpose is to prevent overvoltage damage to the detection diode of the 8WR meter that measures .

The output of the transmitter (including the transmitting section of the transceiver) is normally connected to the antenna element through an antenna feeder, but if the output impedance of the transmitter differs from the characteristic impedance of the feeder and antenna element, the power may be reflected at the junction. The impedance matching state of the transmission path can be determined by measuring the standing wave ratio (swtt), which indicates the amount of standing waves generated in the feeder. is practical, and for this purpose the passing form S
A WR meter is used. Since the pass-through type BWR meter is well known, I will not discuss it in detail, but the secondary side output voltage, which is proportional to the traveling wave power (transmission power) passing through the primary side of the directional coupler and the reflected wave power, is expressed as a small signal high frequency signal. Each power value can be read by rectifying it with a diode and using an indicator needle, or it can be directly read using an SWR value scale calculated from these.

Figure 1 is a connection block diagram of a wet meter, and the SwR meter 4 is used between the transmitter 1 and the antenna 2, which connects the transmitter 1 and the antenna 2, but for multi-band applications with a wide frequency range. An antenna tuner that can perform impedance matching over a wide range is sometimes used, but the antenna team also includes an SWR meter, and adjustments are made while checking the fart meter. Since the SWR meter doubles as a pass-through wattmeter, it is normal to first adjust the output power to the maximum, then switch to 8WR and adjust to the minimum 8WR. The closer the SWR is to 1.0, the better, but a value up to about 1.3 is considered to be an acceptable value. However, if the output of a high power transmitter is applied to a completely unmatched circuit, an unexpectedly large reflected wave voltage may be applied to the detection diode and destroy it. Since the reflected wave voltage under normal conditions is originally extremely small, 5WR1,
In order to read 3 or less with less error, the detection diode is required to have good linearity, especially at small inputs, and this type of diode has a characteristic of low reverse breakdown voltage, so what is a high-performance 8WR meter? There is a problem that it is easily damaged.

On the transmission 4i machine side, when using a semiconductor amplifier (transistor, etc.) in the final stage, in order to prevent damage to the amplifying semiconductor itself due to antenna mismatch, especially on high output machines, the output is reduced when there is mismatch in the output circuit. It is safe because it has a limiting circuit, but when a vacuum tube type linear amplifier (booster) is connected or a final stage vacuum tube type transmitter has automatic output adjustment (ALC), it has no effect on antenna mismatch. Invalid. Figure 2 shows a part of the vacuum tube transmitter circuit,
The ALC circuit includes a front stage section 11 a driver stage 12 a final stage output tube 13
When the grid current flows through the output tube 13 in the automatic drive and the potential changes, the diodes 18m and 18b
A voltage obtained by rectification is applied to the front section 11 to lower r-in. Output tuning circuit consists of coil 14 variable capacitor 15
．． 16, which matches the impedance of the load connected to the output terminal 17 by tuning by changing the capacitance ratio of 15 and 16. External ALC terminal 19 is used to input the ALC control output of the linear amplifier. As mentioned above, ALC is S
Since it has nothing to do with wR and it takes time to adjust the output tuning circuit, the diode of the SWR meter is likely to be destroyed before matching is completed.

Therefore, as described in claim 1, the present invention provides an SWR meter that measures the matching state of an antenna circuit by placing a person between the antenna terminal and the antenna of a wireless transmitter. By deriving the detected output voltage and using it as the ALC control voltage of the transmitter, S
This is an SWR meter that is designed to prevent overvoltage damage to the detection diode of the WR meter, and an example of an applied circuit is shown in FIG.
Connect the input 41 of the WR meter (sometimes included in the antenna tuner) 4, and connect the antenna to the output 42. 41
There is a directional coupler 43 between and 42, one of its secondary outputs is rectified by a traveling wave detection diode 44 to obtain an output power indicating voltage 44a, and the other secondary output is a reflected wave. The detection diode 45 is rectified and the SwR indicating voltage E
45a, which is switched by a switch 46 (or separately) and read by a meter.Although a detailed circuit explanation will be omitted, this is the basic form of a conventional SwR meter.

In the present invention, the output voltage of the reflected wave detection diode 45 is 45 m.
is added to the comparison input 47m of the voltage converter/lator 47, and below the set value of the reference human power 47b, the output voltage 47a is zero, and when it exceeds the set value 47b, the converter/lator 47 inverts and outputs the output voltage 47e. Therefore, it is necessary to pull this out through the output terminal 48 and apply it to the external ALC terminal 19 of the transmitter.As soon as a reflected wave voltage exceeding a predetermined value is applied to the detection diode, the ALC voltage is applied to the transmitter. This reduces the transmission output and prevents the diode 45 from being destroyed. Since condensers and mother rake have various characteristics, it is necessary to use one that provides an output with an appropriate polarity for the ALC voltage of the transmitter, but if convenient, the polarity may be matched through a voltage inverter. Note that FIG. 3 only shows the outline of the configuration of the circuit of the present invention, and some additional circuits are also required for implementation.

[Brief explanation of the drawing]

Figure 1 is a connection diagram of the transmitter and SWR meter, Figure 2 is a diagram of the vacuum tube type transmission final stage circuit and ALC circuit, and Figure 3 is a diagram of the switch of the present invention.
This is an example of the R meter.' 1... Transmitter, 2... Antenna, 3... Feeder, 4... SWR meter, 43... Directional coupler, 44...
...Traveling wave detection diode, 45...Reflected wave detection diode, 47...Voltage converter/lator. Patent applicant Yaesu Musen Co., Ltd. mi Figure 2 4PALc not shown

Claims (2)

[Claims] (1) In an 8WR meter that measures the matching state of the antenna circuit by placing a person between the antenna terminal of the wireless transmitter and the antenna, the reflected wave detection output voltage from the antenna is derived and used as the ALC control voltage of the transmitter. A swR meter is characterized in that by using the swR meter, overvoltage destruction of a detection diode-P of an 8WR meter is prevented. (2) The reflected wave detection output voltage used as the ALC control voltage of the transmitter is determined by comparing the reflected wave detection voltage with the detection level reference voltage using a voltage converter/4 router. The output voltage is zero if it is below the reference voltage, and when the reflected wave detection voltage exceeds the detection level reference voltage, the converter/lator is inverted and generates a control output, as described in claim 1. 8WR meter.