JP3002018U - APC circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object to provide a transmission output control (APC) circuit that enables automatic control of transmission output even with a minute high-frequency detection output. [Structure] An amplification unit and a variable attenuator are connected to a stage subsequent to the high frequency detection unit of the high frequency detection type APC circuit, and then a power amplifier or a voltage / current conversion circuit via a comparison amplification unit and a loop filter. It is possible to automatically control the transmission output even with a minute high-frequency output by inputting it to the excitation amplification section.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an APC circuit capable of automatically controlling transmission output even with a minute output.

[0002]

[Prior art]

 FIG. 6 shows a conventional transmission output automatic control (APC) circuit. The high-frequency output extracted from the low-pass filter 61 is converted into direct current, and the desired amplification that can be varied by the comparison amplification unit 63 is obtained. The signal is compared with the reference voltage set for the output to prevent oscillation after comparison and amplification, and the voltage / current conversion circuit 65 (or The voltage is converted into a current (or the voltage value is converted), a supply current is supplied to the transistor of the excitation amplification unit 66, and a signal is sent to the bipolar power module 67.

Further, as shown in FIG. 7, when a MOS-FET power module is used, the input from the loop filter 64 of FIG. 1 to the voltage control terminal of the MOS-FET power module 72, In some cases, an amplifier circuit was provided after the loop filter 64 and input to the voltage control terminal.

In addition, as shown in FIG. 8, in order to obtain a small amount of power, a through circuit 83 that passes a power module (MOS-FET type or bipolar type) is provided, or a small output is exclusively used. In some cases, the final stage was dedicated to switch between normal output and small output.

However, these devices (excluding the circuit of FIG. 8) have a controllable limit with respect to the minimum transmission output, and the square-law characteristic of the diode of the high-frequency detector causes detection at a small output. There is a limit to the minimum input level due to the decrease of the output level, the method of the comparison amplification section, and the amplification degree. At a small output of several tens of mW, stable APC cannot be applied, and even at the minimum output, 200 ~ Several hundred mA was required.

[0006]

[Problems to be solved by the device]

 The present invention solves the above-mentioned problems, and it is possible to automatically control the transmission output even with a minute high-frequency detection output. Depending on the distance between callers, it is several tens mW at a very short distance and maximum output at a long distance. It is an object of the present invention to provide an APC circuit that enables appropriate selection of transmission output (can be operated in an energy-saving manner), has a small number of parts, and can reduce cost and design time.

[0007]

[Means for Solving the Problems]

 According to the present invention, a high-frequency detector of a conventional high-frequency detector APC circuit is connected with an amplifier and a variable attenuator, and then a power amplifier or voltage-current converter circuit is connected via a comparison amplifier and a loop filter. By inputting the signal to the excitation amplification section through the transmission amplification section, it is possible to automatically control the transmission output even with a minute high frequency output.

[0008]

[Action]

 According to the present invention, the detection output from the high frequency detecting section is first amplified and then further amplified by the comparison amplifying section, so that the lowering of the level is compensated to remove the limit of the minimum input level of the conventional APC circuit. You can

[0009]

【Example】

 1A shows an embodiment of the present invention, in which an amplifying section 12 is provided between a high frequency detecting section 11 and a comparison amplifying section 13. After extracting the high-frequency component from the low-pass filter 10 that helps reduce REI (radio interference) and has little attenuation for high-frequency waves, the high-frequency component is detected as direct current, and one diode is generally used for detection. However, a method of averaging the high frequency voltage by using two is also used. The signal output from the high frequency detection unit 11 enters the amplification unit 12, amplifies the voltage, and then connects the comparison amplification unit 13 composed of a transistor, an IC, or an opamp to the desired transmission output. Comparative amplification is performed with the reference voltage value set to obtain The connected loop filter 14 for preventing oscillation is composed of a time constant circuit including a resistor and a capacitor for stabilizing the transient response characteristic of the APC circuit. (This may be omitted.) Then, the output from this loop filter 14 is input to the power control terminal of the MOS-FET power module 15 and the transmission output is controlled by applying a constant control voltage. You can do that. When the output voltage of the comparison amplification unit 13 is not sufficient, the amplification unit 12 may be connected after the loop filter 14.

FIG. 1B shows an example in which the bipolar module 18 is used, but the signal from the loop filter 14 is transferred to the transistor in the excitation amplifier 16 via the current-voltage conversion circuit 17. Is used as a signal for controlling the amount of current supplied to the bipolar module 18, and by controlling the high frequency input level to the bipolar module 18, the APC circuit operates.

FIG. 2 is also an embodiment of the present invention, and a minute / normal output selector switch 19 capable of switching between minute output and normal output is provided between the high frequency detecting section 11 and the comparison amplifying section 13. Although the amplifier 12 is connected, in practice, three types of circuits as shown in FIGS. 3A to 3C are conceivable.

In FIG. 3A, a negative return ring amplification circuit 20 is connected between the high frequency detection unit 11 and the comparison amplification unit 13 and between the negative return amplification unit 13 and the negative return amplification unit 13. The resistance value of the circuit 20 can be changed. The amplification degree can be switched by switching the resistance value with the High / Low switch. In addition to this, as shown in FIG. 3B, a method of switching the attenuation amount in front of the amplification unit 12 as one of the methods for expanding the APC available range, or as shown in FIG. There is also a system in which 12 can be used or not used by a switch to select between high frequency normal output and minute output.

4 is also an embodiment of the present invention, a variable attenuator 21 is connected between the high frequency detector 11 and the amplifier 12, and then the reference amplifier of the comparison amplifier 13 is connected. The voltage is fixed, and the setting of the transmission output is switched by changing the amount of attenuation of the variable attenuator 21. In this case, if the variable attenuator 21 having a sufficient amount of attenuation is used, it is possible to set continuously (steplessly) from a minute output to a normal output.

In FIGS. 2 and 3 (a) to 3 (c), regarding the switching of the transmission output, the switching of the reference voltage setting (due to the addition of the minute / normal switching) and the switching of the amplification stage are performed in two places. However, in the circuit of FIG. 4, it is possible to continuously change from minute to normal output with only one change (change) of the attenuation amount, which contributes to simplification of the circuit.

The above is the MOS-FET power module. In the case of the bipolar power module in FIG. 5, the high-frequency component is detected by the high-frequency detector 11 from the low-pass filter, and the variable attenuator 21 and the amplifier are detected. The signal flow to 12, the comparison amplification unit 13, and the loop filter 14 is the same as that of the MOS-FET power module, but the output of the loop filter 14 is input to the voltage-current conversion circuit 15, and the output is excited. The high-frequency level input to the amplification unit 16 and applied to the bipolar power module 18 is changed to control the transmission output. This point is the difference between using the FET module and the bipolar (normal transistor) power module, but the present invention can be used for both.

In the conventional bipolar power module of FIG. 5, the high frequency input level to the power module is increased / decreased by controlling the supply current to the excitation amplification stage 16, and APC is applied. In the power module, the high frequency input level to the power module is increased / decreased and APC is applied. Furthermore, in the nearest MOS-FET power module, the transmission output is given by applying a bias voltage to the control terminal of the power module. Since the control is performed and no current is required, the circuit configuration is simpler than that of the conventional bipolar power module.

[0017]

[Effect of device]

 Originally, for example, when using a portable radio for amateur radio or business use for short-distance communication such as a specific low power transceiver, or when high output is not needed when adjusting antenna radio equipment, etc., miniaturization This is a person who can be used effectively when designing with consideration. However, the present invention does not necessarily have a limit of controllable transmission output. However, in principle, it is possible to apply APC if the detection output from the detection unit is present at all, and even if the high-frequency output detected by the low-pass filter is very small, the power supply It has the effect that stable APC can be applied against voltage fluctuations, temperature changes, etc., and design considerations at high frequency levels become unnecessary, making it easier to perform desktop calculations and designs at DC levels. It is possible to reduce the cost of the product by reducing the number of parts compared to the case where a circuit for exclusive use of minute output like the one described above is provided. Further, the present invention compensates for the level drop of the high frequency detection circuit due to the square characteristic of the diode and removes the limit due to the minimum input level of the comparison amplifier, which has the effect of expanding the APC-enabled transmission output range. is there.

[Submission date] April 8, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

However, these devices (excluding the circuit of FIG. 8) have a controllable limit with respect to the minimum transmission output, and the square-law characteristic of the diode of the high-frequency detector causes detection at a small output. There is a limit on the minimum input level due to the decrease in output level, the method of the comparison amplification unit, and the degree of amplification. At a small output of several tens of mW, stable APC cannot be applied and consumption is performed even at the minimum output. An electric current of 200 to several 100 mA was required.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

In the conventional bipolar power module of FIG. 5, the high frequency input level to the power module is increased / decreased by controlling the supply current to the excitation amplification stage 16, and APC is applied. The power module controls the transmission output by applying a bias voltage to the control terminals of the power module and does not require current, so the circuit configuration is simpler than that of the conventional bipolar power module.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

[0017]

[Effect of device]

 Originally, for example, when using a portable radio for amateur radio or business use for short-distance communication such as a specific low power transceiver, or when high output is not needed when adjusting antenna radio equipment, etc., miniaturization It can be used effectively when designing with consideration. However, the present invention is not without a limit of controllable transmission output. However, in principle, APC can be applied as long as the detection output from the detector exists, even if the high-frequency output detected by the low-pass filter is very small. In addition, there is an effect that stable APC can be applied to fluctuations in power supply voltage, temperature changes, etc., and it becomes unnecessary to study the design at high frequency level, which facilitates desktop calculation and design at DC level. The number of parts can be reduced compared to the case where a circuit for exclusive use of minute output is provided, so that the cost of the product can be reduced. Further, the present invention compensates for the level drop of the high frequency detection circuit due to the square characteristic of the diode and removes the limit due to the minimum input level of the comparison amplifier, which has the effect of expanding the APC-enabled transmission output range. is there.

[Brief description of drawings]

FIG. 1A is a block diagram showing an embodiment of the present invention when a MOS-FET power module is used. (B) A block diagram showing an embodiment of the present invention when a bipolar power module is used.

FIG. 2 is a block diagram showing an embodiment of the present invention when a minute / normal output changeover switch is provided in the amplification section.

FIG. 3A is a block diagram showing an embodiment of the present invention when the amplification unit of FIG. 2 is used as a negative feedback amplification circuit. (B) A block diagram showing an embodiment of the present invention using a method of switching the amount of attenuation before the amplifying part of FIG. FIG. 3C is a block diagram showing an embodiment of the present invention when switches are provided before and after the amplifying unit of FIG.

FIG. 4 uses a power module of MOS-TET,
The block diagram which showed one Example of this invention when an attenuator is used before and behind an amplifier part.

FIG. 5 is a block diagram showing an embodiment of the present invention when a bipolar power module is used and an attenuator is used before and after the amplification unit.

FIG. 6 is a block diagram showing a conventional circuit of the present invention when using a bipolar power module.

FIG. 7 is a block diagram showing a conventional circuit of the present invention when a MOS-FET power module is used.

FIG. 8 is a block diagram showing a conventional circuit of the present invention when switches are provided at both ends of a power module.

[Explanation of symbols]

 10 Low Pass Filter 11 High Frequency Detector 12 Amplifier 13 Comparison Amplifier 14 Loop Filter 15 MOS-FET Power Module 16 Excitation Amplifier 17 Current Voltage Converter 18 Bipolar Power Module 19 Micro / Normal Output Switch 20 Negative Feedback Amplifier 21 Variable Type attenuator

Claims (3)

[Scope of utility model registration request] 1. An output from a power module is input to a low-pass filter, the high frequency extracted from the low-pass filter is subjected to direct current detection in a high frequency detection section, and a comparison amplification section,
In the APC circuit that automatically controls the transmission output by sending a control signal to the excitation amplification unit via the power module or the voltage-current conversion circuit via a loop filter, between the high frequency detection unit and the comparison amplification unit, In the case where the high-frequency detection output extracted from the low-pass filter is minute by providing an amplifier and inputting the output from the loop filter to the excitation amplifier via the power module or the voltage / current conversion circuit, Also, an APC circuit characterized by being able to automatically control the transmission output. 2. The APC circuit according to claim 1, wherein an amplifying section having a changeover switch capable of changing the amplification degree is connected between the high frequency detecting section and the comparison amplifying section. 3. The APC according to claim 1, wherein the transmission output is automatically controlled by sending a control signal to the power module.
In the circuit, the output of the variable attenuator is connected between the high-frequency detector and the reference voltage fixed type comparator / amplifier so as to be input to the amplifier, and the output from the loop filter is supplied to the power module or the power module. An APC circuit capable of automatically controlling a transmission output from a minute high-frequency detection output extracted from the low-pass filter to a normal transmission output by inputting the voltage to the excitation amplification unit via a voltage-current conversion circuit.