JP2684848B2 - Transmission power control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission power control system, and more particularly to a transmission power control system in a radio transmitter capable of changing settings of transmission frequency and transmission power, such as a transmitter for satellite communication earth station.

[0002]

2. Description of the Related Art A conventional transmission power control method is shown in FIG.
2, the output power of the RF amplifier 5 is detected by the detector 8, converted into output power data by the A / D converter 10 and the detection voltage / output power converter 11, and this output power data is transmitted. The control loop is configured to control the attenuation amount of the variable attenuator 1 so as to match the power set data.

Further, the detector 8 of this control loop and the A / D
The linearizer 9 arranged between the converter 10 and the converter 10 has a temperature characteristic, and the temperature characteristic of the detector 8 is corrected in an analog manner.

[0004]

In this conventional transmission power control method, when the output frequency of the local oscillator 29 is changed to change the transmission frequency, an error occurs in the output power due to the frequency characteristic of the detector 8. There is a drawback to

Further, since the temperature characteristic of the detector 8 is corrected in an analog manner, there is a drawback that the adjustment is difficult and incomplete.

Further, a conversion table 30 referred to when the detection voltage / output power converter 11 converts the output data of the A / D converter 10 into output power data is written in the ROM, and this ROM is prepared in advance. Therefore, there is a drawback that an error occurs in the output power due to the variation of the detection characteristics of the detector 8.

Further, when the transmission power set data is changed, it takes a time corresponding to the response time of the control loop until the output power converges to the set value, so that there is a drawback that the convergence is slow.

A first object of the present invention is to provide a transmission power control system capable of reducing an error in output power due to a change in setting of the transmission frequency.

A second object of the present invention is to provide a transmission power setting method capable of easily and accurately correcting an error in output power due to a temperature change.

Further, a third object of the present invention is to provide a transmission power setting method capable of reducing an error in output power due to variations in detection characteristics of a detector.

[0011]

A transmission power setting system of the present invention uses a variable attenuator and a local oscillation signal whose frequency is set to a signal in an intermediate frequency band passing through the variable attenuator. Equipped with a mixer that performs frequency conversion into a signal in the transmission frequency band, a power amplifier that inputs the signal output from this mixer, and a detector that detects the output power of this power amplifier.The output voltage of this detector and the transmission power In a transmission power control method for controlling the amount of attenuation of the variable attenuator based on setting information, an A / D converter for inputting an output voltage of the detector and output data of the A / D converter are used as the power. A first storage circuit in which a correspondence table for converting into output power data of the amplifier is written, and the A / D by referring to the correspondence table
A detection voltage / output power converter for converting output data of the converter into the output power data, and the output generated due to the frequency characteristic of the detector when the transmission frequency is changed by changing the frequency setting information. A second memory circuit in which data for correcting an error in power data is written in association with the frequency setting information, and correction data including data read from the second memory circuit in correspondence with the frequency setting information. A first correction unit that corrects either the transmission power setting information or the output power data; and a first correction unit that does not correct the transmission power setting information and the output power data by the first correction unit. The first control means for generating a signal for controlling the attenuation amount of the variable attenuator so that the output data of the correction means of FIG.

Further, the transmission power setting method of the present invention includes a temperature detecting means for outputting temperature data indicating an ambient temperature and the output power data generated due to the temperature characteristic of the detector when the ambient temperature changes. A third memory circuit in which the data for correcting the error of is written in association with the temperature data,
It may be configured to include second correction means for sending the data read from the third storage circuit in correspondence with the temperature data to the first correction means as a part of the correction data.

Further, according to the transmission power setting method of the present invention, a plurality of the correspondence tables are written in the first storage circuit, and which of the correspondence tables is referred to by the detection voltage / output power converter is designated. It may be configured to include a fourth memory circuit in which the data to be written is written.

Furthermore, in the transmission power setting method of the present invention, the signal for controlling the attenuation amount of the variable attenuator is transmitted so that the output power of the power amplifier substantially matches the power represented by the transmission power setting information. It may be configured to include second control means that is generated corresponding to the power setting information and is combined with the signal generated by the first control means and is sent to the variable attenuator.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

The input signal in the intermediate frequency band is level-controlled by the variable attenuator 1, amplified by the IF amplifier 2, and then converted into a transmission frequency band by the mixer 3 and the filter 4, and R
The power is amplified by the F amplifier 5 to obtain an output signal. The frequency synthesizer 6 generates a local oscillation signal used in the mixer 3. The controller 7 controls the oscillation frequency of the frequency synthesizer 6 so that the transmission frequency becomes the frequency designated by the frequency channel set data.

The detector 8 detects the output power of the RF amplifier 5, and the output voltage of the detector 8 is A / A via the linearizer 9.
It is input to the D converter 10, digitized, and further converted into output power data by the detection voltage / output power converter 11.

Since the detection characteristic of the detector 8 varies for each individual detector, in the present embodiment, the A / D indicating the output voltage of the detector 8 for the three detection characteristics T1, T2 and T3 shown in FIG. A table showing the correspondence between the output data of the converter 10 and the output power data showing the output power of the RF amplifier 5 is a detection voltage / output power conversion data table T1, T2.
It is previously written in the ROM 12 as T3. Further, the detection voltage / output power conversion data table number corresponding to the detection characteristic closest to the detection characteristic of the detector 8 actually incorporated in the device among the detection characteristics T1, T2, T3 is stored in the EEPROM 13 as a table select number D. Write as. The detection voltage / output power converter 11 reads the detection voltage / output power conversion table corresponding to the table select number D from the ROM 12 by the selector 14 and refers to the output data of the A / D converter 10 as the output power data. Since the conversion is performed, accurate output power data is output even if the output power of the RF amplifier 5 changes in a wide range.

The amount of attenuation of the variable attenuator 1 is controlled so that the output power data output from the detection voltage / output power converter 11 coincides with the transmission power set data. Since the errors due to the frequency characteristics and the temperature characteristics are included, the present embodiment corrects the transmission power set data so as to compensate for these errors.

Since the frequency of the signal input to the detector 8, that is, the transmission frequency, corresponds to the frequency channel set data, the transmission power set so as to compensate for the error in the output power data due to the frequency characteristic of the detector 8. The data for correcting the data is associated with the frequency channel set data as shown in FIG. 3 and written in the EEPROM 13 as the frequency correction data table T4.

Further, the ambient temperature is detected by the temperature sensor 15, and the detection signal is inputted to the A / D converter 17 through the buffer amplifier 16 and digitized. Since the value to be corrected for the transmission power set data so as to compensate the error of the output power data due to the temperature characteristic of the detector 8 changes depending on the output power, the A / D converter 17 outputs the value as shown in FIG. A table of temperature data and correction data corresponding to the output power setting value is written in the ROM 12 as a temperature correction data table T5.

The selector 18 is controlled by the controller 7 to read the correction data corresponding to the frequency channel set data from the frequency correction data table T4. The selector 19 reads the correction data corresponding to the output of the A / D converter 17 from the temperature correction data table T5. These two correction data are added by the adder 20 and input to the adder 21 to correct the transmission power set data.

The output power data including an error caused by the frequency characteristic and the temperature characteristic of the detector 8 and the transmission power set data corrected so as to compensate for these errors of the output power data are input to the comparator 22. The output data of the computing unit 23 is converted into a voltage by the D / A converter 24,
Variable attenuator 1 via adder 25 and buffer amplifier 26
When the attenuation amount is controlled, a value is calculated so that both input data of the comparator 22 coincide with each other, and the value is output.

In this embodiment, when the output voltage of the D / A converter 27 controls the attenuation amount of the variable attenuator 1 via the adder 25 and the buffer amplifier 26, the output power of the RF amplifier 5 is the transmission power set data. The control data to be input to the D / A converter 27 so as to substantially match the power specified by is written in the ROM 12 as a transmission power control data table T6 corresponding to the output power set value as shown in FIG. I'm out. The selector 28 transmits the control data corresponding to the transmission power set data to the transmission power control data table T.
The data is read out from the No. 6 and output to the D / A converter 27.

The output voltages of the D / A converters 24 and 27 are added by the adder 25, and the attenuation amount of the variable attenuator 1 is controlled via the buffer amplifier 26. When the transmission power set data is changed, first, the attenuation amount of the variable attenuator 1 is changed by the control from the D / A converter 27, and the residual error of this change is corrected by the control from the D / A converter 24. . By doing so, it is possible to speed up the convergence of the output power when the transmission power set data is changed.

In the present embodiment, of the various data tables and table select numbers D, only the table select number D and the frequency correction data table T4 which are unavoidable when the detector 8 actually incorporated in the apparatus is not determined are EEPRO.
Write to M13, other data table in ROM12
Is written in. Therefore, RO that writes a large amount of data
M12 can be manufactured and inspected regardless of device assembly and inspection,
At the time of assembling / inspecting the device, only writing to the EEPROM 13 and inspection need be performed, so that the time for assembling / inspecting the device can be shortened. Since the amount of data written in the EEPROM 13 is small, a serial interface having a small capacity can be used. The ROM 12 is also used to store programs required in various places in this embodiment.

In the above-described embodiment, the transmission power set data is corrected to compensate the frequency characteristic and temperature characteristic of the detector 8. However, the output power data itself output from the detection voltage / output power converter 11 is corrected. Even in this case, the effect of the present invention can be obtained similarly.

[0029]

As described above, the present invention includes the second memory circuit in which the data for correcting the error of the output power caused by the frequency characteristic of the detector when the transmission frequency is changed is written. By correcting the output power using the data of the second storage circuit, there is an effect that the error of the output power due to the setting change of the transmission frequency can be reduced.

Further, the present invention comprises the temperature detecting means and the third memory circuit in which the data for correcting the error of the output power due to the temperature characteristic of the wave detector is written, and corresponds to the output data of the temperature detecting means. By correcting the output power using the data of the third storage circuit described above, it is possible to easily and reliably correct the error in the output power due to the temperature change.

Further, according to the present invention, a first storage circuit in which a plurality of correspondence tables for converting the output voltage of the detector into output power data are written in consideration of variations in the detection characteristics of the detector, and actually, A fourth storage circuit in which data showing a correspondence table corresponding to the detection characteristic closest to the detection characteristic of the detector incorporated in the device is written, and the correspondence table indicated by the data of the fourth storage circuit is used. By obtaining the output power data,
There is an effect that the error of the output power due to the variation of the detector can be reduced.

Furthermore, according to the present invention, the attenuation amount of the variable attenuator is controlled based only on the transmission power setting information so that the output power substantially matches the power represented by the transmission power setting information, and the output power by this control is controlled. By controlling the residual error based on the output voltage of the detector and the transmission power setting information, it is possible to speed up the convergence of the output power when the set value of the output power is changed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram for explaining variations in detection characteristics of the detector 8 in FIG.

FIG. 3 is a frequency correction data table T4 in FIG.
FIG. 3 is a diagram showing an example of the configuration of FIG.

FIG. 4 is a diagram showing a configuration example of a temperature correction data table T5 in FIG.

FIG. 5 is a transmission power control data table T in FIG.
It is a figure which shows the structural example of 6.

FIG. 6 is a block diagram showing an example of a conventional transmission power control method.

[Explanation of symbols]

 1 Variable Attenuator 3 Mixer 5 Power Amplifier 6 Frequency Synthesizer 7 Controller 8 Detector 10, 17 A / D Converter 11 Detection Voltage / Output Power Converter 12 ROM 13 EEPROM 14, 18, 19, 28 Selector 15 Temperature Sensor 20 , 21, 25 adder 22 comparator 23 calculator 24, 27 D / A converter

Claims (4)

(57) [Claims] 1. A variable attenuator, a mixer for frequency-converting an intermediate frequency band signal passing through the variable attenuator into a transmission frequency band signal using a local oscillation signal whose frequency is set by frequency setting information. A power amplifier for inputting the signal output from this mixer and a detector for detecting the output power of this power amplifier are provided, and the amount of attenuation of the variable attenuator based on the output voltage of this detector and the transmission power setting information. In the transmission power control method for controlling the A / D converter, the A / D converter for inputting the output voltage of the detector and the correspondence table for converting the output data of the A / D converter into the output power data of the power amplifier are written. A first storage circuit, a detection voltage / output power converter that converts the output data of the A / D converter into the output power data by referring to the correspondence table, and the frequency setting information is changed and transmitted. Lap A second memory circuit in which data for correcting an error of the output power data caused by the frequency characteristic of the detector when the wave number is changed is written in association with the frequency setting information, and the second memory circuit. First correction means for correcting either the transmission power setting information or the output power data with correction data including data read from a memory circuit corresponding to the frequency setting information; The first of the output power data
And a first control means for generating a signal for controlling the amount of attenuation of the variable attenuator so that the output data of the first correction means coincides with those not corrected by the correction means. Transmission power control method. 2. A temperature detecting means for outputting temperature data indicating an ambient temperature, and data for correcting an error of the output power data generated due to a temperature characteristic of the detector when the ambient temperature changes. A third memory circuit written in association with the data, and a data read from the third memory circuit in correspondence with the temperature data is sent to the first correcting means as a part of the correction data. 2. The transmission power control method according to claim 1, further comprising: two correction means. 3. A plurality of the correspondence tables are written in the first memory circuit, and any one of the correspondence tables is used as the detected voltage /
3. The transmission power control system according to claim 1, further comprising a fourth memory circuit in which data designating whether or not the output power converter refers is written. 4. A signal for controlling the attenuation amount of the variable attenuator is generated corresponding to the transmission power setting information so that the output power of the power amplifier substantially matches the power represented by the transmission power setting information. 4. The transmission power control system according to claim 1, further comprising second control means for synthesizing with the signal generated by the first control means and sending it to the variable attenuator.