JP2003188741A - Transmission output control circuit and method for communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission output control system in which control can be performed to quicken convergence into set transmission output and to widen a dynamic range by generating an attenuation quantity control signal suited to the attenuation quantity/current characteristics of a variable attenuator for controlling transmission power. <P>SOLUTION: The transmission output control circuit has a D/A converting means for generating an attenuation quantity control signal by dividing the range of attenuation quantities to be controlled into a plurality of segments, predetermining the representative value of the gradient of the attenuation quantity relative to the passing current value of the variable attenuator for each attenuation quantity segment according to the known attenuation quantity/ current characteristics of the variable attenuator, determining a quantity obtained by multiplying the inverse of the representative value by a prescribed proportional constant as a weight of the attenuation quantity in the relevant segment, dividing the attenuation quantity to be controlled for each attenuation quantity segment, making them belong to the respective attenuation quantity segments, weighting and adding the attenuation quantity for each segment and a gain switching circuit for amplifying the detection value of the transmission power by switching a gain corresponding to a switching signal generated by comparing the transmission power with a prescribed threshold. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission output control device and a transmission output control method for an outdoor unit of a wireless communication device,
In particular, it has a transmission circuit and an attenuation control circuit, and the transmission circuit is
Input the IF transmission signal from the interface line, and input IF
After frequency converting the transmission signal to the microwave band and amplifying it to a predetermined output, the microwave transmission signal is given to the variable attenuator to attenuate the transmission power, and the output of the variable attenuator is transmitted via the transmission driver, The attenuation amount control circuit relates to a transmission output control circuit that generates an attenuation amount control signal to control the attenuation amount of the transmission power by the variable attenuator, and a transmission output control method using the transmission output control circuit.

[0002]

2. Description of the Related Art Conventionally, a transmitter / receiver of this type (a device which is installed outdoors is also called an ODU (OUT DOOR UNIT outdoor device)) uses an attenuator (detector voltage) through a loop amplifier to maintain a constant transmission power. Attenuator, hereafter referred to as ATT) ALC control method by analog loop to control (also called automatic level control circuit) was adopted.

FIG. 13 is a block diagram showing a conventional example of a transmitting / receiving apparatus. IFL which is the interface side with the indoor equipment
(Interface line) is connected to indoor communication equipment and cable, and antenna ANT is installed on the antenna side.
Are connected. The reception circuit of this communication device includes a reception driver RX, an amplifier 10b, a mixer 11b, and a demultiplexer 12, and a signal flows from the antenna ANT to the IFL. The transmission circuit includes a multiplexer 12 and a mixer 11.
a transmission main circuit including a, an amplifier 10a, a variable attenuator (ATT) 9, an amplifier 10, and a transmission driver TX, and an attenuation amount control circuit for generating a control signal to be given to the variable attenuator 9 for adjusting the gain of the transmission circuit Is provided in the form of a feedback circuit. The transmitted signal flows from IFL to ANT. Further, the transmission / reception device includes a duplexer (DUP) 13 for switching the transmission / reception communication mode.
Usually, the multiplexer and the demultiplexer are configured as one unit. The MX / DMX 12 in FIG. 13 is the unit.

The attenuation control circuit includes a coupler 17, a detector 8, an analog amplifier 16, and a low pass filter (LPF) 1.
8 and VI converter 19 are provided.

A part of the transmission output is branched by the coupler 17 and converted into a voltage by the detector 8. The detected voltage is amplified by the analog amplifier 16 and smoothed by the low pass filter (LPF) 18, and the smoothed voltage is converted into a current by the VI converter 19 and input to the variable attenuator 9 as a control signal. .

When the transmission power is high, the detection voltage increases and the current applied to the ATT 9 increases, so that the gain is narrowed and the transmission power decreases. On the contrary, when the transmission power is low, the detection voltage is small and the current applied to the ATT 9 is low, so that the gain is increased and the transmission power is increased. In this way, constant transmission power is maintained. The output control characteristic of the transmission circuit is determined by the loop gain. This conventional method has a problem that if the linearity of the characteristics of the detector 8 and the ATT 9 is not good, the loop gain becomes unstable and the control loop becomes unstable.

In order to solve the above-mentioned problems of the analog loop of the transmitter / receiver, a method of A / D converting the detection voltage of the transmitter / receiver of FIG. 13 and controlling the ATT gain with a control panel equipped with a CPU is available. is there. FIG. 14 is an example of such a transmission / reception apparatus, and is a block diagram in which a main part of an automatic level control apparatus is described in association with the apparatus of FIG. In FIG.
Parts given the same reference numbers as in FIG. 13 have the same functions as the corresponding parts in FIG. In this device, the variable attenuator (ATT) 9 attenuates the passing radio modulation signal at an attenuation rate corresponding to the control signal value. The transmission output is
A part is branched by the coupler 17 and converted into a voltage by the detector 8. The detected voltage is converted into a digital signal by the A / D converter 36 and then input to the control circuit (CONT) 33.
The control circuit 33 includes a CPU 34 and a memory 35. The memory 35 holds a correspondence table between the output of the A / D converter 36 and the control signal given to the ATT 9. CPU34 is A / D
When the output signal of the converter 36 is received, the memory 35 is accessed, the correspondence table is referred to, and the digital signal representing the control signal value given to the ATT 9 is output. The digital signal is converted into an analog signal by the D / A converter 31. The analog voltage signal output from the D / A converter 31 is converted into a current by the VI converter 19 and input to the variable attenuator 9 as a control signal.

An automatic transmission level control device similar to the transmission / reception device of FIG. 14 is described in Japanese Patent Laid-Open No. 2000-349738.

In this device, the control circuit controls the amplitude value data of the radio modulation signal (corresponding to the signal input from the IFL of FIG. 3) generated by the signal generation unit and the predetermined value held in the memory. Data is compared at every arbitrary timing, the distribution of the compared difference data is obtained, and a control signal for controlling the attenuation amount of the variable attenuator is output based on the distribution of the difference data. The wireless modulation signal is compensated by the correction value corresponding to the mode value of the difference data. According to this configuration, the statistical control is performed in which the error component of the output radio modulated signal is corrected for a long period of time in accordance with the correction value having a large error frequency, which has many sample values.

[0010]

In both the automatic transmission level control device shown in FIG. 14 and the automatic level control device described in the publication, the output of the transmission circuit is digitally processed by the control device. / D conversion is required, and further D / A conversion is required to convert the output of the control device into an analog control signal of ATT9. But A
Since the resolution of / D conversion and D / A conversion is limited, there is a problem that fine control cannot be performed.

Further, the above automatic transmission level control device has the following problems. Generally, the relationship between the control amount that controls the attenuation amount of the variable attenuator and the control attenuation amount that is controlled by the control amount is not linear in a wide range of the transmission output but has a curved shape. Therefore, even if the control amount is set so as to compensate for the attenuation amount deviation, the control attenuation amount generated by the control amount differs depending on the transmission output level, so that at a certain transmission output level, high-speed automatic control of the output level is achieved. However, other transmission power levels are not guaranteed to achieve proper power level automatic control. In the automatic transmission level control device described in the above publication, by setting the control amount so as to compensate for the attenuation amount deviation that statistically has a high appearance frequency, by preventing the attenuation amount deviation from appearing, Although it is intended to speed up the convergence to the set output level, this method requires time to accumulate statistical data, and the processing program becomes complicated and the amount of calculation becomes large. It is thought that there is.

A first object of the present invention is to control the transmission output by using the above-mentioned control device equipped with a CPU, in which fine control is not hindered by the limit of resolution in A / D conversion and D / A conversion. A method and a transmission power control device are provided. A second object of the present invention is to provide a transmission output control method and a transmission output control device capable of rapidly converging to a set transmission output level in a wide range of the transmission output level.

[0013]

In order to achieve the above object, a transmission output control circuit of the present invention has a transmission circuit and an attenuation amount control circuit, and the transmission circuit outputs an IF transmission signal from an interface line. After inputting, frequency-converting the input IF transmission signal to the microwave band and amplifying it to the specified output, the microwave transmission signal is given to the variable attenuator to attenuate the transmission power, and the output of the variable attenuator is transmitted to the transmission driver. Sent via
The attenuation amount control circuit is configured by giving the following characteristics to a transmission output control circuit that generates an attenuation amount control signal and controls the attenuation amount of the transmission power by the variable attenuator.

The range of the attenuation amount for which the attenuation amount control is performed is divided into a plurality of sections, and the representative value of the gradient of the attenuation amount with respect to the passing current value of the variable attenuator for each attenuation amount section,
When the weight is defined as the weight of the attenuation amount of the section, the amount obtained by multiplying the reciprocal of the representative value by a predetermined proportional constant is determined in advance according to the known attenuation amount / passing current characteristic of the variable attenuator. , A transmission power detection means for branching the output signal of the transmission driver and detecting it to generate a detection signal, and the detection signal
The transmission power value is generated by A / D conversion, the attenuation amount corresponding to the transmission power value is compared with the attenuation amount corresponding to the set transmission power value to generate an attenuation amount deviation, and the attenuation amount is generated. An information processing means for calculating an updated attenuation amount by adding an attenuation amount correction value determined to compensate for the deviation to the attenuation amount corresponding to the current transmission power value, and the updated attenuation amount by the attenuation It is divided into quantity sections and assigned to respective attenuation quantity sections, and an analog signal proportional to the weighted addition quantity obtained by adding the weights to the attenuation quantity of each section and adding the analog signals is generated as an attenuation quantity control signal. It is provided with D / A converting means for outputting, and signal converting means for converting the output of the D / A converting means into an electric signal suitable for control of the variable attenuator and supplying the electric signal to the variable attenuator.

As described above, the updated attenuation amount is divided into the attenuation amount sections and assigned to the respective attenuation amount sections,
By adding the weights to the attenuation amounts of the respective sections and adding them, the attenuation amount control suitable for the attenuation amount / current characteristic curve of the variable attenuator can be performed.

The D / A converting means D / A converts the attenuation amount of each section into an analog signal to generate an analog signal corresponding to the attenuation amount of the section, and corresponds to the attenuation amount of the section. It is desirable to add the weighted analog signal to the analog signal and add it to generate an attenuation amount control signal.

As a concrete embodiment of the D / A conversion means,
A plurality of stages of D / A converters corresponding to a plurality of attenuation amount sections and an adder circuit are provided, and the plurality of stages of D / A converters count the attenuation amounts that are sequentially updated, and then the respective D / A The converter is
Each count value is converted into an analog signal and an analog signal corresponding to the amount of attenuation in each section is generated.
The analog signal generated for each A converter may be configured to be weighted and added to the section, and the addition result may be output as the output of the D / A conversion unit.

It is desirable that the attenuation amount control circuit further has a gain switching circuit. The gain switching circuit switches the gain according to a switching signal corresponding to whether the transmission power is higher than a predetermined threshold value or lower than the threshold value, amplifies the output signal of the transmission power detection means, and amplifies the amplified signal. The output signal is output to the information processing means. in this way,
By switching the gain of the amplifier according to the magnitude of the transmission power, the dynamic range of the transmission output control circuit can be expanded.

In the gain switching circuit, the switching signal is
When the transmission power is the first logic level indicating that the transmission power is higher than the predetermined threshold value, the conduction state is set, and when the transmission power is the second logic level when the transmission power is equal to or lower than the threshold value, the cutoff state is set. It is possible to have a transistor switch and an amplifier circuit that amplifies a gain of 1 when the transistor switch is in a cutoff state and amplifies with a gain smaller than 1 when the transistor switch is in a conductive state.

The gain switching circuit may include a log amplifier for logarithmically amplifying the output of the amplifier circuit. In this way, output control can be performed in dBm units.

The information processing means has a processor unit and a memory, and the memory stores a table of attenuation amounts with respect to transmission power values. When the processor unit receives the current transmission power after the transmission power is set. , Referring to the table, comparing the attenuation amount corresponding to the current transmission power value with the attenuation amount corresponding to the set transmission power value, generating an attenuation amount deviation, and compensating for the attenuation amount deviation. It is desirable to add the attenuation amount correction value defined in 1) to the attenuation amount corresponding to the current transmission power value, calculate the updated attenuation amount, and transmit the updated attenuation amount to the D / A conversion means.

The information processing means compares the set transmission power value with a predetermined threshold value and supplies the switching signal to the gain switching circuit, and the table of the attenuation amount with respect to the transmission power value corresponds to the contents of the switching signal. It includes two types of tables, a first table for high transmission power and a second table for low transmission power, and these two types of tables include a predetermined low transmission power region and low transmission of the high transmission power table. It is desirable that the power table overlaps with a predetermined high transmission power region.

The information processing means refers to one of the first and second tables corresponding to the switching signal transmitted to the gain switching circuit, calculates the updated attenuation amount, and then the D / A conversion means. The transmission power value corrected corresponding to the attenuation amount control signal transmitted from the D / A conversion means to the variable attenuator is received via the transmission power detection means, and from the received transmission power value, It is possible to have an attenuation amount control program that refers to the table and repeats the control operation of generating the updated attenuation amount and transmitting it to the D / A conversion means.

The attenuation amount control program classifies the attenuation amount deviation of the attenuation amount corresponding to the current transmission power with respect to the attenuation amount corresponding to the set value of the transmission power according to the size, and determines the attenuation amount deviation belonging to each category. Set the same correction value, and
A large correction value is set for a category to which a large attenuation amount deviation belongs, and at the time of control, a procedure for proceeding from correction with a large correction value to correction with a small correction value depending on the magnitude of the attenuation amount deviation may be included. desirable. By executing this procedure, the speed at which the transmission output converges to the set value can be improved.

The memory of the information processing means may have a table describing the correction value of the transmission power for each temperature in order to compensate the temperature dependence of the output of the transmission power detection means.

The transmission output control method of the present invention is a transmission output control method using the transmission output control circuit of the present invention and includes the following processing procedure. The range of the attenuation amount in which the attenuation amount control is performed is divided into a plurality of sections, and the representative value of the gradient of the attenuation amount with respect to the passing current value of the variable attenuator is known for each attenuation amount section. Is determined in advance according to the attenuation / passing current characteristics of, and the amount obtained by multiplying the reciprocal of the representative value by a predetermined proportional constant is defined as the weight of the attenuation in the section,
The transmission output signal is branched and detected to generate a detection signal, the detection signal is A / D converted to generate the transmission power value, and the attenuation amount corresponding to the transmission power value is set to the set transmission power. An attenuation amount deviation is generated by comparing with the attenuation amount corresponding to the value, and an attenuation amount correction value determined to compensate for the attenuation amount deviation,
The updated attenuation amount is calculated by adding it to the attenuation amount corresponding to the current transmission power value, and the updated attenuation amount is divided into the above attenuation amount sections and assigned to the respective attenuation amount sections. The quantities are weighted and added to generate an analog signal proportional to the weighted addition result and output as an attenuation amount control signal.

In the transmission output control method described above, the generated attenuation amount deviations are classified in advance according to their sizes, the same correction value is set for the attenuation amount deviations belonging to the same category, and a large value is set. The process of setting a large correction value for the category to which the attenuation amount deviation belongs and generating the updated attenuation amount is
The process proceeds from correction with a large correction value to correction with a small correction value according to the magnitude of the attenuation amount deviation, and the process of calculating the updated attenuation amount that is executed according to the procedure is generated by A / D conversion. The process of reading the transmitted power value and the attenuation corresponding to the read transmission power
A process of generating an attenuation amount deviation by comparing with the attenuation amount corresponding to the set transmission power, and which category of the classification preliminarily classified by the magnitude of the attenuation amount deviation the generated attenuation amount deviation belongs to. And a process of generating a renewed attenuation amount by adding a predetermined attenuation amount correction value for the category to which the attenuation amount deviation belongs to the attenuation amount corresponding to the read transmission power. Including, the transmission output control method,
A process of controlling the transmission power by the updated attenuation amount by the process of generating the updated attenuation amount, reading the transmission power value generated by the control, and repeating the process of generating the updated attenuation amount, Can be included.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. In the drawings referred to in the following description, parts having the same reference numerals as those in FIGS. 13 and 14 have the same functions as the corresponding parts in FIGS. 13 and 14.

FIG. 1 is a block diagram showing an entire embodiment of a communication device of the present invention. The communication device of this embodiment also
The communication device is a microwave band communication device like the communication devices of FIGS. 13 and 14, and is an outdoor unit (ODU) installed outdoors. An indoor communication device is connected to the IFL side of FIG. 1 via a cable, and an antenna is connected to the ANT side. A diplexer 13 is connected to the antenna to switch between transmission and reception.

The receiving circuit of the communication device of this embodiment is shown in FIG.
3 and the same as the receiving circuit of FIG. 14, the receiving driver RX,
The amplifier 10b and the mixer 11b are provided. Receive driver
The microwave band signal received by the RX is sent to the amplifier 10
After being amplified to a predetermined power level by b, it is input to the mixer 11b. The mixer 11b is a local oscillator (L
O) 14 outputs a local oscillation signal to generate an intermediate frequency signal from the microwave band signal. The intermediate frequency signal is demultiplexed by the MX / DMX 12 and then sent to the indoor unit through the IFL.

The transmission circuit of the communication apparatus of this embodiment also includes an attenuation amount control circuit for automatically controlling the transmission power.
The forward circuit of the transmission circuit is the same as the corresponding circuit of the transmission circuit of FIGS. 13 and 14, and includes a mixer 11a and an amplifier 1.
0, a variable attenuator ATT9, an amplifier 10a and a transmission driver TX are provided, and a signal flows from IFL to ANT.

The intermediate frequency signal sent from the indoor unit via the IFL is multiplexed by the MX / DMX 12. Mixer 1
1a frequency-converts the intermediate frequency signal input by the local oscillation signal generated by the local oscillation circuit 14 to generate a microwave band transmission signal. The transmission signal is amplified by the amplifier 10 to a predetermined power level and then given to the variable attenuator ATT9.

The variable attenuator ATT9 attenuates and outputs the input signal in response to a control signal generated by an attenuation amount control circuit described later. The output of the variable attenuator ATT9 is amplified by the amplifier 10a and then transmitted by the transmission driver TX from the antenna ANT via the duplexer DUP13.

The attenuation control circuit includes a coupler 17, a detector 8, a gain switching circuit 7, an A / D converter 6, a control device (C
An ONT board) 3, a D / A converter (D / A device) 2 and a V / I converter 1 are provided.

A part of the transmission output is branched by the coupler 17 and converted into a voltage by the detector 8, and the gain switching circuit 7
And a control panel (CON
T) 3 is connected. The CONT board 3 is equipped with a CPU 4 and an EEPROM 5, and through the D / A conversion device 2 and V / I conversion circuit 1, the ATT 9
It is connected to the. In this embodiment, the D / A device 2 uses the ATT
9 increases the resolution of the attenuation control signal supplied to 9, and
In order to reduce the time required for the transmission output to converge to the set value, it is configured as a 4-stage DA circuit (a circuit in which D / A converters are connected in 4 stages), as described later.

FIG. 2 is a circuit diagram of the gain switching circuit 7 of FIG. In this circuit, the output of the detector 8 is connected to the non-inverting input terminal of the operational amplifier circuit 63. The inverting input terminal of the operational amplifier circuit 63 is connected to the output terminal via the feedback resistor 64, and is also grounded via the resistor 65 and the MOS FET 62. A CMOS FET 66 is connected to the gate of the MOS FET 62 as an input buffer. A log amplifier 67 (option) is connected to the output of the operational amplifier circuit 63.

In this circuit, the MOS FET 62 functions as a switch element, and the switching signal of the switch element is input from the CMOS FET 66. When the MOS FET 62 is off, the operational amplifier 63 and the resistor 64 form a voltage follower circuit. Therefore, in this case, the detector 8
Output voltage is output from the operational amplifier 63 as it is.
When MOS FET 62 is on, operational amplifier 63 and resistor 6
Reference numerals 4 and 65 form a normal amplifier circuit. Therefore, the output voltage of the detector 8 is output with a gain determined by the resistors 64 and 65 (which is set smaller than 1 in this embodiment). In this way, the gain of the amplifier circuit by the operational amplifier 62 can be switched by the switching signal. Switching of the MOS FET 62 is controlled by the CONT board 3 via the input buffer 66. When the transmission power control is performed in units of dBm, the output of the operational amplifier 63 is connected to the log amplifier 67.

FIG. 3 is a diagram showing an example of the relationship between the detection voltage of the gain switching circuit 7 and the transmission power level when the log amplifier 67 is connected. In the figure, the curve labeled "LOW" is the characteristic curve when the MOS FET 62 is off, and the curve labeled "HIGH" is the characteristic curve when the MOS FET 62 is on. In this way, a wide dynamic range of the attenuation control circuit can be obtained with respect to the transmission power.

The A / D converter 6 A / D converts the output of the gain switching circuit 7. The CONT board 3 is an information processing device including a CPU 4 and an EEPROM 5. The transmission power value (A /
A table of attenuation values (input values of the D / A device 2, hereinafter, referred to as D / A values) with respect to output values of the D converter 6 and hereinafter referred to as A / D values) is stored.

First, the CPU 4 switches the gain of the gain switching circuit 7 so that an appropriate input of the A / D converter 6 can be obtained for the set transmission power. Then, under the switched gain, the D / A value corresponding to the actual value of the A / D value (hereinafter referred to as the actual value of the D / A value) and the set A / D value are set. Compared with the corresponding D / A value (hereinafter referred to as the target value of the D / A value), the deviation of the actual value of the D / A value from the target value of the D / A value (hereinafter referred to as the attenuation amount deviation) The D / A value is corrected so as to compensate and the updated D / A value is output to the D / A device 2. The D / A device 2 outputs the updated D / A value as D / A conversion in a manner described later. VI converter 1 is D /
The output voltage value of the A converter 2 is converted into a current value and supplied to the ATT 9 as an attenuation amount control current signal.

FIG. 4 is a circuit diagram showing details of the configuration of the D / A device 2 of FIG. This D / A device 2 is a device that inputs the updated D / A value (digital signal) from the CONT board 3 and generates an attenuation amount control signal (analog signal) suitable for the attenuation amount / current characteristic of the ATT 9. Is. Therefore, normal D / A
Rather than outputting an analog signal proportional to the input digital signal as in a converter, the relationship between the input D / A value and the output attenuation control signal is based on the attenuation / current characteristic curve of ATT9. It is a device that outputs an attenuation amount control signal corresponding to the input D / A value so that the relationship between the attenuation amount and the current becomes similar.

Usually, a diode is used for the ATT 9 in FIG. 1, and the amount of attenuation is determined according to the current flowing. The relationship between the current and the controlled attenuation amount (controlled attenuation amount) has a characteristic as shown by the solid curve in FIG. 5, so that it is several to ten times as high and low as the sensitivity. There is a difference (the vertical axis in FIG. 5 is a logarithmic scale). Therefore, if the region with high sensitivity and the region with low sensitivity are controlled by using the same control attenuation amount-to-current ratio, an error or instability may occur in the control. In order to prevent this problem, in the D / A device 2 of the present embodiment, the relationship between the input D / A value and the output attenuation control signal is the attenuation of the ATT9 / the attenuation of the current characteristic curve. Input D / A to be similar to the relationship with current
An attenuation amount control signal corresponding to the value is generated.

In the present embodiment, the attenuation amount A of ATT9
A plurality of (n) small sections ΔA (j) (j = 1, 2, ...
n), and a current I that generates an arbitrary attenuation amount A of ATT9 is generated as the sum of the current values ΔI (j) corresponding to the attenuation amount ΔA (j) in each section j. That is, I = ΔI (1) + ΔI (2) + ... + ΔI (n) = ΔA (1) cotθ ₁ + ΔA (2) cotθ ₂ + ... ΔA (n) cotθ _n. theta _j of ....... (1) (1), the j-th attenuation-current characteristic curve of ATT9
It is the tilt angle in the section. That is, tan θ _j = ΔA
(J) / ΔI (j) (see FIG. 5).

As described above, in the D / A device 2, the relationship between the input D / A value α and the output attenuation amount control signal β is determined by the attenuation amount A of the ATT 9 and the current characteristic curve A and the current I. Characterized to be similar to the relationship with. Therefore, β = Δβ (1) + Δβ (2) + ... + Δβ (n) = Δα (1) cotθ ₁ + Δα (2) cotθ ₂ + ... Δα (n) cotθ _n. (2) The right side of the equation (2) can be realized as follows. That is, the input D / A value (α) of the D / A device 2 is divided into n sections so as to correspond to the respective sections of the attenuation amount A of the ATT 9 and each section Δα (j) is determined. Δα (j) in each section is amplified with a gain cotθ _j and added for all sections.

However, when the equation (2) is realized by an actual device, the value of θ changes even within one section of the attenuation / current characteristic curve.
The average value of tan θ, or tan θ at the section j by the tan θ at an arbitrarily set point for each section
can represent _j . In this specification, the representative value of the gradient is the value of tan θ that is representative in each section j as described above. Therefore, in order to reduce the error caused by the fact that the representative value of the gradient is different from the actual gradient at each point in the section, when the attenuation / current characteristic curve is divided, a segment with a constant gradient is set to 1 It is a desirable mode to take one section.

In the D / A device 2 of this embodiment, four D / A devices are used.
A D / A converter 40 consisting of D / A converters (DA-1, DA-2, DA-3, DA-4) is provided, and each D / A converter (DA-1, DA-2,
DA-3, DA-4) are connected to the operational amplifier 45 via resistors 41-44. These resistors 41-44 and operational amplifier 45
Constitutes a well-known adder circuit. Therefore, the operational amplifier 45 compares the output voltage of the D / A converters (DA-1, DA-2, DA-3, DA-4) with the resistance values R ₄₁ , R ₄₂ , R ₄₃ of the resistors 41-44. R
It is amplified with a gain proportional to the reciprocal of ₄₄ and the sum is output. That is, the operational amplifier 45 is a D / A converter (DA-1, D
A-2, DA-3, DA-4) output voltage, R ₄₁ ,
Weighting is carried out in proportion to the reciprocal of R ₄₂ , R ₄₃ and R ₄₄ , and the sum is output.

The D / A device 2 is associated with the equation (2) as follows. The attenuation / current characteristic curve in Fig. 5 is 4
It is divided into sections, and the D / A converter (DA-1, DA-1,
DA-2, DA-3, DA-4) for each category of D / A value α Δα
(J) (j = 1, 2, 3, 4) is input. Also, R
₄₁ , R ₄₂ , R ₄₃ , and R ₄₄ are such that their reciprocal numbers are proportional to cotθ ₁ , cotθ ₂ , cotθ ₃ , and cotθ ₄ of the equation (2) (hence, R ₄₁ , R ₄₂ , R ₄₃ , R ₄₄ is each
tan θ ₁ , tan θ ₂ , tan θ ₃ , and tan θ ₄ ). Therefore, the operational amplifier 45 outputs a signal proportional to the attenuation amount control signal β corresponding to the D / A value α.

The updated D / A value can be read from the CONT board 3 as four D / A converters (DA-1, DA-2, DA-3, DA-4) as follows.
Entered in. For example, four D / A converters (DA-1, DA-2,
When both DA-3 and DA-4) are 8-bit D / A converters, the D / A value α is sequentially input from DA-1 by dividing into numerical values of 256. For example, D / A output from CONT board 3
If the value shows 550, DA-1 has the value 255
Is counted. Next, the numerical value 255 is also counted in DA-2. The remaining number 40 is counted in DA-3. Therefore, the D / A converters (DA-1, DA-2) output the analog signal corresponding to the numerical value 255, and the D / A converter DA-3 outputs the analog signal corresponding to the numerical value 40. in this way,
The D / A value is DA-1, DA-2, D sequentially from the smallest value to the largest value.
Assigned to A-3 and DA-4. In this way, the data from the CONT board is sequentially used from DA1. Next, the operation of the embodiment of the present invention will be described in detail with reference to the drawings.
In the wireless communication device of this embodiment, the IFL (int
IF signal is input from the erface line), the frequency is converted to the microwave band, amplified to a predetermined output, and output from ANT. This equipment is equipped with an ALC circuit equipped with an attenuation control circuit to keep the level of transmission output constant. Further, an arbitrary transmission level can be set by a command from a communication signal from an external device to the CONT board.

A part of the transmission power is branched by the coupler 17 and converted into a voltage by the detector 8. This voltage is amplified by the operational amplifier 63 shown in FIG. This operational amplifier 63 is a MOS FE
The gain can be switched depending on whether T62 is on or off. The higher the transmission output level, the higher the diode detection voltage, but if it is too high, it will reach the upper limit of the operating voltage of the A / D converter. If the level of the transmission output becomes low, the detection voltage of the diode becomes low, but if it is too low, the voltage becomes lower than the resolution of A / D and is easily affected by noise. Therefore, when the transmission output is high, the MOS FET 62 is turned on to reduce the gain of the operational amplifier circuit. If the transmission power is low, MO
Turn off the S FET and increase the gain of the operational amplifier circuit. At this time, the MOS FET 62 is C through the CMOS gate 66.
Switching is controlled by the ONT board 3. The relationship between the detected voltage and the output level at this time is shown in FIG. In this way, a wide dynamic range can be obtained.

The CONT board 3 controls the D / A device (FIG. 1) 2 according to the A / D value of the detection voltage. At this time, CPU of CONT board 3
Performs control based on the data in EEPROM 5. For example, when the transmission output value (A / D value) is set to 10 dBm,
When the EEPROM 5 indicates 300, the CPU of the CONT board 3 sets the A / D conversion value of the detection voltage to 300.
Control the D / A device 2 (D / A converter DA-1, DA- of the D / A device 2
2, give appropriate values to DA-3 and DA-4).

FIG. 6 is a flow chart showing an embodiment of a transmission output control algorithm using the transmission output control circuit of the present invention. The control algorithm classifies the generated attenuation amount deviations in advance according to the size thereof, sets the same correction value to the attenuation amount deviations that belong to the same category, and classifies the attenuation amount deviations that belong to the large attenuation quantity deviations to the same category. The process of setting a large correction value and generating the updated attenuation amount is executed according to the procedure, from the correction with the large correction value to the correction with the small correction value according to the magnitude of the attenuation amount deviation. It

First, the transmission output is detected by the wave detector 8 via the coupler 17 to detect the voltage value, and the A / A of the voltage value is detected.
The digital value after D conversion is read (step S81).
Next, compare with the set reference value (step S8
2) The category of the added value (value to be added to the current D / A value) is confirmed (step S83), and the unit numerical value to be added is selected (step S84). Select the added value from the previous D
/ Add to A value, convert to current value and ATT according to the current value
Is controlled (step S85). During this period, as the control progresses, a large addition value is added (addition value = ± 6
Steps S81 to S85 are repeated for each addition value selection unit from 4) to addition of a small addition value (addition value = ± 1).

For example, the transmission output value is 10 dB as described above.
When set to m, the EEPROM 5 describes 300, but when the A / D conversion value is 150, there is a difference of 100 or more from the target value, so 64 D / A values are added. If the A / D value is 305, the target value is +5, so the D / A value is reduced by 1 five times, and finally the target value is converged to exactly 300 or 300 ± 1. Here, the addition value given to the D / A device 2 is changed from 64 to 1 in order to converge at a high speed, and finally to move one bit at a time is to converge with an error of ± 1.
FIG. 7 is a diagram showing the state of this convergence, where the vertical axis is the amount of attenuation and the horizontal axis is time. It is shown that the output rapidly converges to the desired output from the initial state and changes to the vibration mode of 1 bit at a time.

In the communication apparatus of the present embodiment, it is assumed that the transmission output level can be set to any level from -10 dBm to +15 dBm, and the capacity of that number is secured in the table of the EEPROM 5. Two types of tables are prepared according to the gain of the operational amplifier 63 of the line switching circuit 7, and a part of them is overlapped. This is to eliminate the discontinuous portion in response to the control command of the output level from the external device, to control continuously and smoothly, and to calculate the control target data when there is correction by temperature or frequency. .

FIG. 8 shows an example of two overlapping tables in the range of approximately 5 dBm to 0 dBm. When it is set to +6 dBm or more, TABLE1 is used, and when it is set to -1 dBm or less, TABLE2 is used. TAB when +5 to 0 dBm
LE1 is used preferentially, but the previous setting value is
With -1 dBm, TABLE2 is still used in the case of 0 dBm this time. Also, when using TABLE1, set the gain of the operational amplifier circuit 63 in FIG.
When using the CONT board 3 is set to MOS so that it is set to "LOW".
Turns on / off the FET 62.

A diode is usually used for the ATT 9 in FIG. 1, and the amount of attenuation is determined according to the current flowing. Here, the attenuation / current characteristic curve of ATT9 is divided into four and assigned to DA-1 to DA-4. In the circuit of FIG. 4, the outputs of DA-1 to DA-4 are combined by the adder circuit by the operational amplifier 45. At this time, weighting is performed by the resistors 41 to 44. The values of the resistors 41 to 44 are selected so that the gain for each input signal to the adder circuit at this time is the reciprocal of the gradient (tan θ) in the corresponding section of FIG. In this way, the data from the CONT board is used sequentially from DA-1. DA-1 for example
-When DA-4 is an 8-bit D / A converter, data (control value)
DA-1 counts from 0 to 255, then DA-2 counts from 0 to 255 while keeping DA-1 counts at 255, then DA-2 and DA-1 counts Keeping 255 at
DA-3 is counted from 0 to 255, and finally DA-3, DA-
2, DA-4 from 0 to 2 while keeping the count value of DA-1 at 255
Count up to 55. Since the output of the operational amplifier 45 is a voltage output, the output of the operational amplifier 45 is the current − of FIG.
It is converted into a current by the voltage conversion circuit (VI conversion) 1 and the amount of attenuation is determined according to the output voltage of the D / A device 2. As a result, almost linear ATT control is obtained with respect to the D / A control value as shown in FIG. The D / A control (gives a numerical value corresponding to the control amount to the D / A converter and performs D / A conversion to perform analog control) by such a mechanism keeps the transmission output level constant. be able to.

In the above embodiment, the log amplifier 67 is provided in the circuit of FIG. The use of the log amp 67 is optional and the invention can be practiced without it. However, since the detected voltage increases exponentially in accordance with the transmission power, the dynamic range can be further expanded by linearizing with the log amp. In this case, the other circuit configuration can be used as it is, only by changing the contents written in the EEPROM 5 shown in FIG.

Further, as another embodiment of the data of the EEPROM 5, by adding / subtracting a correction value to / from the data of the EEPROM 5 according to the temperature and the frequency, it becomes possible to correct the temperature characteristic of the transmission output and the frequency characteristic. In this case, the temperature is read by the CPU 4 using the temperature sensor and the frequency is read by the local oscillator 1.
The CPU 4 judges based on the setting information of 4 (see FIG. 1).
Further, regarding temperature characteristic correction, as shown in FIG. 10, correction is performed using a matrix of temperature and output level. Write the matrix table in another address of EEPROM5.

FIG. 11 is a diagram showing the transmission output dependence of the output level versus temperature curve of the detector. As can be seen from FIG. 11, the output level vs. temperature curve of the detector output slightly changes depending on the transmission output. The above matrix table is intended to supplement the transmission output dependent characteristic of the output level vs. temperature curve shown in FIG. The matrix in Figure 10 is
The transmission output is described every 5 dBm and the temperature is described every 20 ° C., and the intermediate value is used by interpolating numerical values. This enables extremely high-precision control over a wide temperature range and a wide transmission output range.

Finally, the transmission output control method of the present invention is carried out using the transmission output control circuit of the present invention, and is executed in the following procedure. (Refer to FIG. 12) The range of the attenuation amount in which the attenuation amount control is performed is divided into a plurality of sections, and the representative value of the gradient of the attenuation amount with respect to the passing current value of the variable attenuator is calculated for each of the attenuation amount sections. A value determined in advance according to a known attenuation amount / passing current characteristic of the variable attenuator, and an amount obtained by multiplying a reciprocal of the representative value by a predetermined proportional constant is defined as a weight of the attenuation amount in the section (step S1), and the transmission output signal Is branched and detected to generate a detection signal (step S
2) The presence / absence of transmission is determined (step S3), and if there is no transmission, the process ends. If there is a transmission, the detected signal is A / D
The converted transmission power value is generated (step S4), the attenuation amount corresponding to the transmission power value is compared with the attenuation amount corresponding to the set transmission power value to generate an attenuation amount deviation, An attenuation amount correction value is calculated so as to compensate the attenuation amount deviation, and the attenuation amount correction value is added to the attenuation amount corresponding to the current transmission power value to calculate the updated attenuation amount (step S5).

Next, the updated attenuation amount is divided into attenuation amount sections and assigned to each attenuation amount section (step S
6), weighting and adding the attenuation amount for each section, generating an analog signal proportional to the weighted addition result and outputting it as an attenuation amount control signal (step S7), and controlling the ATT by the attenuation amount control signal Yes (step S8). The processing from step S2 to step S8 is performed during the transmission period.
Run.

These steps are held in the CONT board 3 as an attenuation control program.

[0063]

As described above, the transmission output device of the wireless communication device of the present invention has the following effects. 1) A wide dynamic range can be obtained by switching the gain of the detection voltage of the transmission output. 2) Divide the attenuation-current characteristic curve of the variable attenuator into multiple sections with almost constant slope, and assign one D / A converter to each section to control the attenuation amount belonging to each section. , The digital attenuation data corresponding to the attenuation correction value is converted to analog attenuation data by the D / A converter in the section, and the analog attenuation data by each D / A converter is converted into the attenuation-current characteristic curve By weighting and adding the reciprocal of the gradient in the section and controlling the variable attenuator with a control current proportional to the addition result, stable control can be achieved that converges to the set value at high speed. 3) Since the control sensitivity of each D / A converter of the D / A device becomes substantially constant, the attenuation amount per bit of the plurality of D / A converters from the low transmission output region to the high transmission output region, that is, , And the resolution of attenuation is almost the same. As a result, the variation of the transmission output due to the 1-bit control error is suppressed to the minimum. 4) Attenuation amount deviations corresponding to the set value of the transmission output are classified according to size, the same correction value is set for the attenuation amount deviations belonging to each category, and the category to which a large attenuation amount deviation belongs Set a large correction value to
By advancing the process from a correction with a large correction value to a correction with a small correction value according to the deviation, it is possible to achieve the pulling of the transmission output up to the set value at high speed, and to stably pull in the transmission output at the convergence point. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing an entire embodiment of a wireless communication device of the present invention.

FIG. 2 is a detailed diagram of the gain switching circuit of FIG.

FIG. 3 is a diagram showing an example of a relationship between a detection voltage and an output level of a gain switching circuit.

FIG. 4 is a circuit diagram showing details of the configuration of the D / A device 2 of FIG.

FIG. 5 is a diagram showing a control attenuation amount / current value characteristic curve of an attenuator.

FIG. 6 is a flowchart showing an example of a transmission output control algorithm using the transmission output control circuit of the present invention.

FIG. 7 is a diagram showing how the attenuation amount converges, showing how the initial state is rapidly converged to a desired output and the vibration mode is changed to a bit-by-bit mode.

FIG. 8 is a diagram showing an example of two tables overlapping in a range of approximately 5 dBm to 0 dBm.

FIG. 9 is a diagram showing a control attenuation amount which is obtained by the device of the present invention and which is substantially linear with respect to a D / A control value.

FIG. 10 is a diagram showing an example of a matrix of temperature and output level for temperature characteristic correction of transmission output.

FIG. 11 is a diagram showing the transmission output dependence of the output level versus temperature curve of the detector.

FIG. 12 is a process flow diagram illustrating a transmission output control method of the present invention.

FIG. 13 is a block diagram showing a conventional example of a transmission / reception device.

FIG. 14 is a block diagram showing another conventional example of a transmission / reception device.

[Explanation of symbols]

1 Voltage / current converter (V / I converter) 2 D / A device 3 control board (CONT board) 4 CPU 5 EEPROM 6 A / D converter 7 Gain switching circuit 8 detector 9 ATT 10, 10a, 10b amplifier 11a, 11b mixer 12 MX / DMX 13 Duplexer 14 Local oscillator 17 Coupler IFL interface line ANT antenna RX receive driver TX transmit driver

Claims (13)

[Claims] 1. A transmission circuit and an attenuation control circuit, wherein the transmission circuit inputs an IF transmission signal from an interface line, frequency-converts the input IF transmission signal into a microwave band, and amplifies it to a predetermined output. After that, the microwave transmission signal is given to the variable attenuator to attenuate the transmission power, and the output of the variable attenuator is transmitted through the transmission driver, and the attenuation amount control circuit generates the attenuation amount control signal to change the variable amount. In the transmission output control circuit that controls the amount of transmission power attenuation by the attenuator, divides the range of attenuation amount for which attenuation amount control is performed into multiple sections, and passes the variable attenuator for each attenuation amount section. The representative value of the gradient of the attenuation amount with respect to the current value is predetermined according to the known attenuation amount / passing current characteristic of the variable attenuator, and the reciprocal of the representative value is multiplied by a predetermined proportional constant to obtain the attenuation amount of the section. The weight of When defining, the attenuation control circuit, a transmission power detection means for branching the output signal of the transmission driver and detecting it to generate a detection signal, and A / D converting the detection signal to generate a transmission power value. Then, the attenuation amount corresponding to the transmission power value is compared with the attenuation amount corresponding to the set transmission power value to generate an attenuation amount deviation, and the attenuation amount determined to compensate the attenuation amount deviation. An information processing unit that calculates the updated attenuation amount by adding the correction value to the attenuation amount corresponding to the current transmission power value; and the updated attenuation amount for each attenuation amount section. D / A conversion means that is assigned to a section, generates an analog signal proportional to a weighted addition amount obtained by adding the weighted amount to the attenuation amount of each period and outputs the analog signal as an attenuation amount control signal, D The output of the A / A conversion means to the variable attenuator And a signal conversion unit that supplies the variable attenuator with an electric signal suitable for the control of the transmission output control circuit of the communication device. 2. The D / A conversion means D / A converts the attenuation amount of each section into an analog signal to generate an analog signal corresponding to the attenuation amount of the section, and the attenuation amount of the section. The transmission control circuit according to claim 1, wherein the analog signal corresponding to is added with the weight and added to generate an attenuation amount control signal. 3. The D / A converter includes a plurality of stages of D / A converters corresponding to the plurality of attenuation amount sections and an adder circuit, and the plurality of stages of D / A converters sequentially perform the updating. After counting the amount of attenuation, each D / A converter converts each count value into an analog signal to generate an analog signal corresponding to the amount of attenuation for each section, and the adder circuit is / A Adds the analog signal generated for each converter by weighting the section and adding the result to D /
The transmission output control circuit according to claim 2, wherein the transmission output control circuit outputs as an output of the A conversion means. 4. The attenuation control circuit further has a gain switching circuit, and the gain switching circuit responds to a switching signal corresponding to whether the transmission power is higher than a predetermined threshold value or lower than the threshold value. The transmission output control circuit according to claim 3, wherein the gain is switched, the output signal of the transmission power detection means is amplified, and the amplified signal is output to the information processing means. 5. The gain switching circuit is rendered conductive when the switching signal is at a first logic level indicating that the transmission power is greater than a predetermined threshold, and indicates that the transmission power is below the threshold. A transistor switch that is turned off when the second logic level is set, and a gain of 1 when the transistor switch is turned off.
5. The transmission output control circuit according to claim 4, further comprising: an amplification circuit that performs amplification according to claim 1 and performs amplification with a gain smaller than 1 when the transistor switch is in a conductive state. 6. The transmission output control circuit according to claim 5, wherein the gain switching circuit includes a log amplifier for logarithmically amplifying the output of the amplifier circuit. 7. The information processing means has a processor unit and a memory, the memory stores a table of attenuation amounts with respect to transmission power values, and the processor unit receives the current transmission power after the transmission power is set. Then, referring to the table, the attenuation amount corresponding to the current transmission power value is compared with the attenuation amount corresponding to the set transmission power value to generate an attenuation amount deviation, and the attenuation amount deviation is calculated. The attenuation correction value set to compensate is added to the attenuation corresponding to the current transmission power value, and the updated attenuation is calculated to calculate D /
The transmission output control circuit according to claim 4, which transmits to the A conversion means. 8. The information processing means compares the set transmission power value with a predetermined threshold value and supplies a switching signal to the gain switching circuit, and the table of the attenuation amount with respect to the transmission power value corresponds to the contents of the switching signal. And includes two types of tables, a first table for high transmission power and a second table for low transmission power, and the two types of tables correspond to a predetermined low transmission power region of the high transmission power table. The transmission output control circuit according to claim 7, wherein a predetermined high transmission power region of the low transmission power table overlaps. 9. The information processing means refers to one of the first and second tables corresponding to the switching signal transmitted to the gain switching circuit, calculates the updated attenuation amount, and calculates the D / A. The transmission power value which is transmitted to the conversion means and is corrected corresponding to the attenuation amount control signal transmitted from the D / A conversion means to the variable attenuator is received through the transmission power detection means, and the received transmission power value is received. 9. The transmission output control circuit according to claim 8, further comprising an attenuation amount control program for repeating the control operation of generating an updated attenuation amount and transmitting the updated attenuation amount to the D / A conversion means by referring to the table. 10. The attenuation amount control program classifies the attenuation amount deviation of the attenuation amount corresponding to the current transmission power with respect to the attenuation amount corresponding to the set value of the transmission power according to the size, and the attenuation amounts belonging to the same category. The same correction value is set for the deviation, and a large correction value is set for the category to which a large attenuation amount deviation belongs, and during control, a large correction value is changed to a small correction value according to the magnitude of the attenuation amount deviation. 10. The transmission output control circuit according to claim 9, which includes a procedure for advancing the processing by the correction by. 11. The memory of the information processing means has a table in which a correction value of the transmission power for each temperature is described in order to compensate for the temperature dependence of the output of the transmission power detection means.
The transmission power control circuit according to claim 7. 12. A transmission circuit and an attenuation control circuit are provided,
The transmission circuit inputs the IF transmission signal from the interface line, frequency-converts the input IF transmission signal to the microwave band, amplifies it to a predetermined output, and then applies the microwave transmission signal to the variable attenuator to increase the transmission power. In the transmission output control circuit, the output of the variable attenuator is attenuated and transmitted through the transmission driver, and the attenuation amount control circuit generates an attenuation amount control signal to control the attenuation amount of the transmission power by the variable attenuator. In the transmission output control method, the attenuation amount range in which the attenuation amount control is performed is divided into a plurality of sections, and the representative value of the gradient of the attenuation amount with respect to the passing current value of the variable attenuator for each attenuation amount section, A value determined in advance according to a known attenuation amount / passing current characteristic of the variable attenuator, and an amount obtained by multiplying a reciprocal of the representative value by a predetermined proportional constant is defined as a weight of the attenuation amount of the section, and a transmission output signal The detection signal is branched and detected to generate a detection signal, the detection signal is A / D converted to generate a transmission power value, and an attenuation amount corresponding to the transmission power value corresponds to a set transmission power value. An attenuation amount updated by generating an attenuation amount deviation by comparing with the attenuation amount and adding an attenuation amount correction value determined to compensate for the attenuation amount deviation to the attenuation amount corresponding to the current transmission power value. The updated attenuation amount is divided for each attenuation amount section and assigned to each attenuation amount section, and the attenuation amount for each section is weighted and added, and an analog proportional to the weighted addition result is calculated. A transmission output control method for a communication device, comprising a processing step of generating a signal and outputting it as an attenuation control signal. 13. The transmission output control method preliminarily classifies the generated attenuation amount deviations according to the size thereof, and sets the same correction value for the attenuation amount deviations belonging to the same category,
In addition, a process of setting a large correction value for a category to which a large attenuation amount deviation belongs and generating an updated attenuation amount is performed from a correction with a large correction value to a correction with a small correction value according to the magnitude of the attenuation amount deviation. The process of calculating the updated attenuation amount, which is executed according to the procedure, is performed by reading the transmission power value generated by A / D conversion and the attenuation amount corresponding to the read transmission power. , A process of generating an attenuation amount deviation by comparing with the attenuation amount corresponding to the set transmission power, and the generated attenuation amount deviation belongs to which category of the classification pre-classified according to the magnitude of the attenuation amount deviation. And a predetermined attenuation amount correction value for the category to which the attenuation amount deviation belongs, and the updated attenuation amount is generated by adding the attenuation amount corresponding to the read transmission power. The transmission output control method controls the transmission power by the attenuation amount updated by the process of generating the updated attenuation amount, reads the transmission power value generated by the control, and updates the transmission power value. Repeat the process to generate the attenuation,
The transmission power control method according to claim 12, further comprising processing.