JP3526815B2 - Variable gain control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a radio receiver and the like.
Automatic Gain Control (AGC)
l) Regarding devices, specifically, CDMA (Code Division M
ultiple Access: Code Division Multiple Access, OFDM (Orth
ogonal Frequency Division Multiplex)
Wireless communication device that communicates using a broadband frequency band
Automatic gain control device that keeps the output constant
You. [0002] 2. Description of the Related Art In recent years, demand for mobile communication such as mobile phones has been increasing.
Is growing. Recently, these mobile communications
There is a CDMA method as a method. This method is
Frequency used by using different codes for each user
Share bandwidth at the same time. To achieve this sharing
Needs to control transmission power with high accuracy. That
Therefore, the transmitter output of the mobile phone has a stable and accurate transmission output.
Variable gain control device that can output
I have. FIG. 17 shows a conventional variable gain control device of a transmitter.
FIG. 3 is a diagram showing a configuration of the device. In FIG.
The transmitter using the gain control device includes a modulator 1 and an up-converter.
Data2, VCO (Voltage Controlled Oscillator:
Pressure controlled oscillator) 3, variable gain amplifier 4, band pass filter
Filter 5, splitter 6, antenna 7, detection circuit 8, integration circuit
9, comparison circuit 10, reference value table 11, variable gain amplification
The amplifier control circuit 12 and the variable gain amplifier control circuit 12
A correction table 13 and an output designating circuit 14.
Is done. The modulated wave modulated by the modulator 1 is up.
Carrier signal generated by VCO 3 in converter 2
Up-converted to the desired transmission frequency.
Upconverted RF (radio frequency) signal is variable
Amplified to the desired output by the gain amplifier 4 and
After the band is limited by the filter 5, it is transmitted to the air from the antenna 7.
Is done. The control of the variable gain amplifier 4 is as follows.
It is. First, an output to be transmitted by the output designating circuit 14 is specified.
Show. The variable gain amplifier control circuit 12 includes the output designating circuit 1
Control of the variable gain amplifier 4 according to the gain specified by the control unit 4
Generate a signal. In the case of a general variable gain amplifier, control
The relationship between signal and gain is linear as shown in FIG.
Absent. FIG. 18 shows a control signal of the variable gain amplifier and its gain.
FIG. When the relationship between the control signal and the gain is not linear,
Variable gain amplification in advance for accurate output control.
Of the unit 4 and the control necessary to realize the gain at that time
A correction table 13 storing the relationship with the signal value is prepared.
The variable gain amplifier control circuit 12 uses the correction table
13 to obtain a desired gain
Determine the value of. [0007] To make the transmission output more stable
The transmission output is detected and the value should be output
Compare with the indicated value and feed based on the comparison result
A method of performing back control is also employed. This feed
The back control method will be described. [0008] Part of the output extracted by the duplexer 6
Is detected by the detection circuit 8 at its level. Detection times
In order to remove the effect of instantaneous fluctuation, the output of
9 performs integration and averaging. From the integration circuit 9
The value of the averaged output is compared with the reference value
Table 11 compares the result with the variable gain amplification
Output to the device control circuit 12. In the reference value table 11
Is correctly output with the output specified by the output designating circuit 14.
Stores the value of the detection level that should be detected when
Have been. The values in this reference value table 11 are
The values measured by experiments are recorded. Variable interest
The gain amplifier control circuit 12 is based on the output result of the comparison circuit 10.
To re-adjust the gain and update the gain control signal
Output is stabilized by performing feedback control. [0009] However, this is not the case.
Such a conventional variable gain control device, such as the following
There was a problem. Mobile communication systems such as CDMA and OFDM
The system uses a wide frequency band. Also,
In these modulation methods, the transmission power is output with higher accuracy.
Force control is required. This output control usually uses a variable gain amplifier.
The control signal (control) of the variable gain amplifier is generally used.
The relationship between the control voltage and the gain is shown in FIG.
Not near. Therefore, in order to perform accurate output control
Is the relationship between the control signal and the gain in advance as described above.
The correction table 13 is created by measuring the
The control signal is obtained by referring to the positive table 13 so as to obtain a desired gain.
The method of generating a signal is adopted. Incidentally, variable gain amplifiers are generally
The operating point of the internal bias changes according to the
The input and output impedance at each gain changes,
As a result, the frequency characteristics change with each gain.
Problems arise. FIG. 19 is a circuit diagram showing the use of each of the variable gain amplifiers.
It is a figure showing the change of the frequency characteristic in acquisition. FIG.
As shown in the figure, the gain deviation due to frequency characteristics
For example, if a correction table is created with frequency fo,
When transmitting at fo, the desired accurate gain control
Can be realized, but other transmission, for example, at frequency f1
If so, there arises a problem that gain control becomes inaccurate. The deviation of the gain characteristic due to such frequency is
As a correction method, a correction table to be referred is set for each frequency.
And there is a way to prepare. Based on the information of the frequency used
To the value of the correction table corresponding to that frequency
This enables accurate gain control at each frequency
To do. Japanese Patent Application Laid-Open No. 7-46064 discloses that
The load after the amplifier without the above amplifier compensation
The matching circuit is measured according to the control information measured and stored in advance.
To operate optimally for the frequency used.
Discloses a method for correcting deviation due to frequency
Have been. However, in these correction methods,
Applies only to the frequency used.
At the same time.
Output corrections for other frequencies.
Not considered. The frequency bandwidth occupied by the transmitted signal is relatively high
If the band is narrow, this correction method is effective,
Same time as in recent CDMA and OFDM systems
Transmission in a system that occupies a wideband frequency in
When transmitting, at frequencies other than the correction target, the desired output
Is not correctly corrected for the
It becomes. Also, if the transmission output is specified only by the total power,
And the power specified for each frequency
In the stem, the gain at frequencies other than the frequency to be corrected is
If not corrected properly, the problem shown in FIG.
Occurs. FIG. 20 shows the power output regulation on the frequency axis.
FIG. 20 is a diagram showing the relationship between the spectrum and the output spectrum.
FIG. 20A shows a normal output spectrum, and FIG.
4 shows an output spectrum in which the numerical characteristics are distorted. FIG.
As shown in (b), the output spectrum with distorted frequency characteristics
In the case of a vector, when transmitting a wideband signal, the
Output power specified for each frequency at outside frequencies
Problem arises. Further, the output is detected as shown in FIG.
When performing gain control by feedback control,
Even if the gain control in the variable gain amplifier is performed correctly,
If the output spectrum is distorted, the detected power value
There is also a problem that it does not properly correspond to the profit. The present invention has been made in view of such problems.
Over all desired variable gain ranges.
Has a wideband frequency characteristic at the same time,
Variable gain control device that can perform accurate output control
The purpose is to do. [0020] A variable gain control device according to the present invention.
The variable gain amplifier capable of varying the gain;
Variable amplifier for controlling gain amplifier to desired gain
Frequency characteristics on the frequency axis at the same time as the control means
Frequency characteristic correction means capable of varying the
Compatible with each unit gainTo correct the frequency characteristics
Means for holding the correction data, and holding the correction data
See meansAnd adjust the frequency characteristics so that the frequency characteristics are corrected.
Frequency characteristic control means for controlling the wave number characteristic correction means,
It is characterized by having. Furthermore, it is constant in the used frequency band.
Frequency characteristic, and the gain of the variable gain amplifier is
Variable gain with variable gain step finer than variable step
Obtaining means and a variable gain control means for controlling the variable gain means.
And a variable gain amplifier and a frequency characteristic compensator.
When frequency characteristics are corrected in combination with the positive circuit
The resulting error with the desired gain can be re-corrected. Further, the frequency characteristic correcting means or the frequency characteristic correcting means may be used.
The variable gain means is constituted by a digital circuit.
By implementing the circuit as a digital circuit,
Degree correction can be realized. In addition, the frequency characteristic correction means may include a frequency
Has a function that can change the scale of the characteristic correction process.
Correction processing of the frequency characteristics according to the bandwidth of the frequency
By changing the scale, the frequency band used
Depending on the width, the target range for frequency
To minimize the load of the frequency characteristic correction process.
Can be A demultiplexing means for demultiplexing the output signal;
Detecting means for detecting the split output signal;
Comparing means for comparing a value detected by the output means with a predetermined value
The variable amplifier control means, and the frequency characteristic control means.
Control means, or at least one of the variable gain control means.
Two control means, based on a comparison result of the comparison means,
The variable gain amplifier, the frequency characteristic correction means, or
Stable by feedback control of variable gain means
Output can be realized. Further, the detecting means may use a frequency band to be used.
For multiple frequencies in the frequency range,
And the comparing means detects each of the detected powers.
The power at the wave number is averaged for each frequency, and
The averaged value for each frequency is used to obtain the desired output.
And compare the result with the predetermined value for each frequency of
Output,The frequency characteristic control means is provided for each of the frequencies.
Feedback control that corrects the frequency correction control based on the comparison result of
And the variable amplifier control means or the
At least one of the variable gain control means is
A feedback circuit for modifying the gain control based on the output of the comparing means.
Perform lock controlCorrects frequency characteristics accurately
be able to. Further, the modulated wave and the narrow band test signal are
Signal transmitting means capable of transmitting a signal,
Narrow band to specify test signal transmission frequency and its timing
Area test signal control means, wherein the signal transmission means includes
The narrow band test signal control is performed for each period during which no modulated wave is transmitted.
Narrow band test signals are sequentially transmitted according to the transmission frequency specified by the means.
Transmitting said comparison means, for each frequency of the narrowband test signal.
The narrowband test signal is transmitted at a corresponding frequency.
The output results from the detection means during the
And collect the values collected for each frequency
Compare with predetermined value for each frequency to get output
And output the comparison result,The frequency characteristic control means is
Correction of frequency correction control based on comparison result for each frequency
The variable amplifier control means.
Stage, or at least one of the variable gain control means
The control means corrects the gain control based on the output of the comparing means.
Perform feedback controlThis allows accurate frequency characteristics
Gender correction can be performed. [0027] BRIEF DESCRIPTION OF THE DRAWINGS FIG.
The preferred embodiment of the variable gain control device according to the present invention will be described in detail.
This will be described in detail. First embodiment FIG. 1 shows a variable gain control device according to a first embodiment of the present invention.
FIG. 3 is a diagram showing the configuration of FIG. Variable gain control device shown in FIG.
Applied to a variable gain amplifier that controls the gain of the transmitter
It is an example. In describing the present embodiment, the same as FIG.
The components are denoted by the same reference numerals. Referring to FIG. 1, the variable gain according to the present embodiment is shown.
The transmitter using the gain control device includes a modulator 1 and an up-converter.
Data 2, VCO3, and the control signal can vary the gain.
Variable gain amplifier 4, frequency at the same time by control signal
Frequency characteristic correction circuit 2 that can vary frequency characteristics on several axes
1 (frequency characteristic correction means), bandpass filter 5,
For each gain of the antenna 7 and the variable gain amplifier 4,
A frequency characteristic correction circuit 21 is provided so as to correct the frequency characteristic.
Frequency characteristic control circuit 22 (frequency characteristic control
Stage), a correction table referred to by the frequency characteristic control circuit 22
23. Control so that the variable gain amplifier 4 has a desired gain
Variable gain amplifier control circuit 12 (variable gain amplifier control
Means), a correction table referred to by the variable gain amplifier control circuit 12.
Cable 13 and an output designating circuit 14.
You. That is, the present variable gain control apparatus
From the conventional variable gain control device shown in FIG.
8, integration circuit 9, comparison circuit 10, and reference value table 11
And remove the frequency characteristic from the output side of the variable gain amplifier 4.
For controlling the positive circuit 21 and the frequency characteristic correction circuit 21
Frequency characteristic control circuit 22 and correction table 23 for
It has a digit structure. Note that the frequency characteristic correction circuit 21
The detailed characteristics and configuration of this will be described later with reference to FIGS.
You. The variable gain control constructed as described above will now be described.
The operation of the control device will be described. First, the variable gain control device
The operation of the transmitter used will be described. Modulated by modulator 1
The modulated wave obtained by the up converter 2 is output from the VCO 3
The desired carrier frequency is set by the generated carrier signal.
Upconverted. Upconverted RF signal
The signal is amplified by the variable gain amplifier 4 and the frequency characteristic is compensated.
After the frequency characteristic is corrected by the correct circuit 21, the bandpass
The band is limited by the filter 5 and transmitted from the antenna 7.
You. Next, a method of correcting the transmission output will be described.
You. When the output specifying circuit 14 specifies the transmission output,
In the gain amplifier control circuit 12, the information of the designated output level is obtained.
And the gain control required to achieve that output level.
The control signal is supplied to the variable gain amplifier with reference to the correction table 13.
Output to 4. The measured values are stored in the correction table 13 in advance.
Between the output level and the gain control signal
Correspondence is recorded. FIG. 2 shows the gain and frequency of the variable gain control device.
FIG. 2A is a diagram showing how characteristics are corrected, and FIG.
FIG. 2B shows the frequency characteristics of the variable gain amplifier 4.
FIG. 2 (c) shows the frequency characteristics of the sex correction circuit 21.
The subsequent frequency characteristics are shown. As shown in FIG. 2A, a variable gain amplifier
4 has different frequency characteristics depending on the magnitude of the gain.
One. To correct this deviation, the frequency characteristic control circuit 2
2 refers to the correction table 23 to determine the output frequency characteristic.
A correction signal to be corrected is output to the frequency characteristic correction circuit 21.
You. The correction table 23 contains information such as measurement in advance.
The output level and the output level
A pair with the value of the correction signal for canceling the generated frequency characteristic
Response is recorded. In the present embodiment, the frequency characteristic correction circuit 2
1, the output of the frequency characteristic of the variable gain amplifier 4 is corrected.
However, in the correction performed by the frequency characteristic correction circuit 21,
In addition to correcting the frequency characteristics of the output of the variable gain amplifier 4,
Frequency of upconverter 2, bandpass filter 5, etc.
The correction may be made to include the characteristic. Here, the recording amount of the correction table 23 is reduced.
Output level according to the target correction accuracy.
And properly thinning out the relationship between the value of the correction signal at that time and recording
And you need a decimated intermediate output level
Is required by calculation from the recorded values of the correction signal before and after
May be determined. FIG. 3 shows a configuration example of the frequency characteristic correction circuit 21.
FIG. 3 is a diagram showing gain and frequency characteristics corresponding to each component.
You. Frequency characteristic correction circuit 21 varies the frequency characteristic
Can be high-pass circuit, notch circuit, low-pass circuit
And so on. In the present embodiment,
The frequency characteristic correction circuit 21 includes a low-pass filter (LP
F) 31, Notch filter with notch characteristics (Notch
Filter) 32 and high-pass filter (HPF) 33
By combining them, the frequency characteristic shown in FIG.
And a frequency characteristic correction circuit 21. Low pass fill
Filter 31, notch filter 32, and high-pass filter 33
Can change the frequency characteristics, for example,
As shown in FIGS. 3A to 3C, each filter has a “characteristic”.
When the frequency characteristic correction circuit 21 is adjusted to "1",
3 (d) has frequency characteristics shown in the upper part, and each filter
When adjusted to “characteristic 2”, the frequency characteristic correction circuit 2
1 has a frequency characteristic shown in the lower part of FIG. Each of the above filter circuits is a constituent element of a filter.
External control using variable elements such as varicaps
By changing the voltage, etc., the cutoff frequency etc.
The frequency characteristics can be varied by changing the frequency characteristics. FIG. 4 shows one configuration of the frequency characteristic correction circuit 21.
FIG. 3 is a diagram illustrating a configuration example of a variable low-pass filter 31 as a unit.
is there. The variable low-pass filter 31 is configured as shown in FIG.
Using a variable capacitance element VC34 such as a varicap as a component
Capacity by changing the control voltage from outside
And consequently the cutoff frequency etc.
You. The above is an example of the variable low-pass filter 31,
Change the frequency characteristics of other filter circuits as well.
As a result, as shown in FIG.
Change the wave number characteristics. The frequency characteristic correction circuit 21
Anything that changes the frequency characteristics as a body can be used.
For example, each of the above filter circuits is placed before and after the variable gain amplifier 4.
It may be divided and installed, or multiple
No. In the above, the frequency characteristic correction circuit 21 is an analog circuit.
Although this is an example of a configuration, a digital circuit may be used. FIG. 5 shows the frequency characteristic correction circuit 21
FIG. 3 is a diagram illustrating an example of a digital circuit, and a non-recursive circuit.
It is composed of roads. In FIG. 5, z^-1Is a delay element
(Delay) 35, Co to Cm are weights which are filter coefficients
The adding coefficients 36 and 37 are adders for adding the tap outputs.
is there. The weight of each tap is controlled by a control signal.
Thereby, an arbitrary frequency characteristic can be realized. Most
In a recent OFDM system, a DSP (digital signal process) is used.
ssor) to perform modulation in the digital part.
In this digital section, the main circuit composed of digital circuits
If it is configured to incorporate the wave number characteristic correction circuit 21,
It can be embodied and is convenient. In addition, the frequency characteristics
Correction of phase besides correction of frequency characteristics
Can also be easily performed. The above-described frequency characteristic correction circuit 21 is the same
For correcting frequency characteristics on the frequency axis at time
Therefore, even when transmitting a wideband signal,
It can output without distortion. As described above, in the first embodiment,
The variable gain control device includes a modulator 1, an up-converter
2, VCO3, variable gain that can vary gain by control signal
The frequency axis at the same time by the gain amplifier 4 and the control signal
A frequency characteristic correction circuit 21 capable of varying the above frequency characteristics,
Bandpass filter 5, antenna 7, variable gain amplifier 4
To correct the frequency response corresponding to each gain of
Frequency characteristic control circuit for controlling frequency characteristic correction circuit 21
22, the correction table 23, and the variable gain amplifier 4
Variable gain amplifier control circuit 12 for controlling
A correction table 13 and an output designating circuit 14 are provided.
Frequency characteristic correction circuit corresponding to the output for each output level of
Refer to the data of the correction table 23 for controlling the road 21.
Thus, for each gain of the variable gain amplifier 4,
The frequency characteristic correction circuit 21 corrects the frequency characteristic.
Over all desired variable gain ranges.
Accurate power control over a wide band.
You. Second Embodiment FIG. 6 shows a variable gain control device according to a second embodiment of the present invention.
FIG. 3 is a diagram showing the configuration of FIG. Variable gain control device shown in FIG.
Also applied to a variable gain amplifier that controls the gain of the transmitter
It is an example. In describing the present embodiment, the same configuration as FIG.
The same reference numerals are given to the components, and the description of the overlapping portions will be omitted.
You. In FIG. 6, the variable rate according to the present embodiment is shown.
The transmitter using the gain control device includes a modulator 1 and an up-converter.
Data 2, VCO 3, variable gain amplifier 4, control signal
Variable frequency characteristics on the frequency axis at the same time
The frequency characteristic correction circuit 21 is controlled.
Frequency characteristic control circuit 22, frequency characteristic control circuit 2
2 refers to the correction table 23,
With approximately constant frequency characteristics and variable gain amplification
Variable gain step finer than the variable gain step of unit 4
Variable attenuator 41 (variable gain means) having
Variable attenuator control circuit 42 (variable gain control
Stage), a correction table referred to by the variable attenuator control circuit 42
43, bandpass filter 5, antenna 7, variable gain increase
Refer to width controller control circuit 12 and variable gain amplifier control circuit 12.
Correction table 13 and an output designating circuit 14
Be composed. That is, the variable gain control device of the present invention
Output side of the frequency characteristic correction circuit 21 of the variable gain control device
And a variable attenuator 41 and a variable attenuator control circuit 42
And a correction table 43 are provided. The variable attenuator 41 is used in a frequency band to be used.
Is almost constant within the variable range of the attenuation.
Frequency characteristics. The gain of the variable attenuator 41
The variable step is a variable step of the gain of the variable gain amplifier 4.
Finer than This variable attenuator 41 is a variable gain amplifier.
Control signal of the device 4 or the control signal of the frequency characteristic correction circuit 21
It is controlled by a control signal separate from the signal. The variable gain control constructed as described above will now be described.
The operation of the control device will be described. In this embodiment, the variable gain
Correction of width controller control circuit 12 and frequency characteristic control circuit 22
And more precise output
This is for controlling. Variable attenuator 41, variable attenuator control
The operation of each part other than the control circuit 42 and the correction table 43 is
The description is omitted because it is the same as that of the first embodiment. The frequency characteristic correction circuit 21
After the performance has been corrected, adjust the output level more precisely.
If necessary, the variable attenuator control circuit 42
The variable attenuator 41 with reference to the
Output corrected by the detector 4 and the frequency characteristic correction circuit 21.
Between the output and the output specified by the output designating circuit 14.
Control to correct. In the correction table 43,
Of the output designating circuit 14 prepared by first measuring
The specified output level, the variable gain amplifier 4 and the frequency characteristic
Is different from the output corrected by the
Recorded for each gain. In the present embodiment, as described below,
The frequency characteristic correction circuit 21 considers the gain in the correction circuit.
Especially effective when compensating only the frequency characteristics without consideration
It is. FIG. 7 shows the gain and frequency characteristics of the variable gain control device.
FIG. 7A is a diagram showing a state in which is corrected.
FIG. 7B shows the frequency characteristics of the gain amplifier 4.
FIG. 7C shows the frequency characteristic of the positive circuit 21 after the correction.
FIG. 7D shows the frequency characteristics after correction by the variable attenuator.
The frequency characteristics are respectively shown. The relationship between the gain of the variable gain amplifier 4 and the control signal
The person in charge measures the correction table 1
3 recorded. The correction data at this time is, for example,
Records data that accurately corrects the gain at the heart frequency fo
Considering the attenuation in the variable attenuator 41 etc.
Therefore, for each gain, the target gain is also
This is the correction value that results in the gain that has been applied. This extra
The value is more finely adjusted by the variable attenuator 41 in the later stage described later.
Because it is possible, it does not have to be so strict. This correction table
The output of the variable gain amplifier 4 controlled based on the
This is shown in FIG. At other frequencies, variable rate
Due to the frequency characteristics of the gain amplifier 4,
Therefore, the value is different from the target gain. FIG.
(B) shows the frequency characteristic of the frequency characteristic correction circuit 21.
ing. Here, in the frequency characteristic correction circuit 21, the frequency
Only the characteristic is corrected, and the gain in the frequency characteristic correction circuit 21 is corrected.
Is not considered, the frequency characteristic correction circuit 21
Output is the final target value of the gain as shown in FIG.
Will be different. As a method of correcting this error, a variable
A method of correcting the gain of the gain amplifier 4 by this error may be considered.
However, the frequency characteristic of the variable gain amplifier 4 depends on its gain.
A new frequency resulting from this gain modification
The characteristic error is corrected again by the frequency characteristic correction circuit 21
Need to do. For accurate output control,
And the variable gain amplifier 4
Has finer variable steps to compensate for errors
There is a need. In the present embodiment, a separate circuit from these circuits is used.
The variable attenuator 41, the variable attenuator control circuit 42, and the correction
The table 43 is installed, and the error
By correcting the difference, control is simplified.
You. Further, the variable attenuator 41 is used in the use frequency band.
It has almost constant frequency characteristics, and has a variable gain amplifier 4 and
The control is performed independently of the control of the wave number characteristic correction circuit 21.
Therefore, the frequency characteristics may change due to this variable attenuator control.
And not. Further, the variable attenuator 41 includes the variable gain amplifier 4
Since the variable step is finer than
The variable steps of the width device 4 may be coarser than this,
Is the correction data of the correction table 13 of the gain control circuit 14,
And correction of the correction table 23 of the frequency characteristic control circuit 22
Less data is needed. A variable gain circuit is used instead of the variable attenuator 41.
There is also a method of using a digital element. As a modulator
Digital such as DDS (Direct Digital Synthesizer)
If a circuit is used, the amplitude etc.
Can be corrected. Use this digital circuit
To realize a variable gain circuit in the third embodiment.
A more detailed description will be given. Third Embodiment FIG. 8 shows a variable gain control device according to a third embodiment of the present invention.
FIG. 3 is a diagram showing a configuration of a digital element as a variable gain circuit.
This is an example of using a child. In the description of the present embodiment,
6, the same components as those in FIG.
The description of the minute is omitted. In FIG. 8, reference numeral 50 denotes digital data conversion.
DDS50 is a digital circuit to be adjusted.
Modulator 51 and variable gain circuit 52 (variable gain
Acquisition means). 53 is the modulation from DDS50
Converts data to analog signal and sends it to upconverter 2
This is a D / A converter for outputting. 54 is a variable rate
Variable gain control circuit (variable gain control
Means, 55 are correction tables referred to by the variable gain control circuit 54.
Table. In the above configuration, digital values are input.
The modulated data obtained is digitally modulated by the DDS 50.
The DDS 50 can output any amplitude and phase.
Process so that this output becomes digital data of the modulated wave.
By using the DDS50 as a modulator
it can. This modulated digital data is stored in a D / A converter
Is converted to an analog signal by the
Amplitude of the digital value output of modulator 51 before conversion to
, The function as the variable gain circuit 52
Has been realized. In the present embodiment, the amplitude is attenuated.
In addition, it is easy to amplify. In addition,
Control with higher accuracy
It becomes possible. Fourth Embodiment FIG. 9 shows a variable gain control device according to a fourth embodiment of the present invention.
FIG. 3 is a diagram showing the configuration of FIG. In describing the present embodiment,
The same components as those in FIG.
Description is omitted. In FIG. 9, reference numeral 60 denotes digital data conversion.
DDS60 is controlled by digital circuits.
And a modulator 61 configured as follows. 62 is the frequency
A characteristic correction circuit (frequency characteristic correction means) 63;
Frequency characteristic control circuit (frequency
Characteristic control means), 64 is referenced by the frequency characteristic control circuit 63
FIG. The frequency characteristic correction circuit 62
Frequency characteristics by digital processing based on frequency bandwidth information
Correction, and reduce the scale of processing related to frequency characteristic correction.
It has a variable function. FIG. 10 shows a frequency composed of digital circuits.
FIG. 9 is a diagram illustrating an example of a configuration of a numerical characteristic correction circuit 62,
It is composed of a return type circuit. The same components as in FIG.
The same reference numerals are given. In FIG. 10, z^-1Is a delay element
Element 35, Co to Cm are weighting coefficients 3 which are filter coefficients.
6, 37 are adders for adding tap outputs, and 38 is a frequency.
Each tap output is taken at an arbitrary composite point according to several bandwidth information.
This is a switch that performs switching for starting. In the frequency characteristic correction circuit 62 shown in FIG.
The processing result is extracted from an arbitrary composite point in the middle and used.
Selected based on the bandwidth information of the frequency
Things. Signal processing using the delay circuit shown in FIG.
, The more complex the frequency characteristics
Although correction can be performed, processing time and scale increase.
You. If the frequency bandwidth used is small,
It is not necessary to correct the frequency characteristics of
Correction of characteristics only within the frequency band
It can often appear. Therefore, in this embodiment,
If the frequency bandwidth used is small, switch
Select the output of the previous tap by switching 38.
This will reduce the time and scale involved in correcting frequency characteristics.
In this way, efficient correction is performed. Fifth Embodiment FIG. 11 shows a variable gain control device according to a fifth embodiment of the present invention.
FIG. 3 is a diagram showing a configuration of the device. In this embodiment, the output signal
It has a circuit to detect, compare and feedback the result.
This is an example of the case. The same components as those in FIGS.
The same reference numerals are given and the description of the overlapping portions is omitted. In FIG. 11, this variable gain control device is
The transmitter used was the variable gain control device of FIG.
Demultiplexer 6 (demultiplexing means), detection circuit 8 (detection means), integration
Circuit 9, comparison circuit 10 (comparison means) and reference value table
11 is provided. A duplexer 6 is provided immediately before the antenna 7 for transmission.
Demultiplex the output. A part of the demultiplexed transmission output is a detection circuit
10 and the level is detected. Frequency characteristic
The frequency characteristics of the output are corrected by the correction circuit 21
Therefore, this detection circuit 10 uses a detection diode or the like.
Power detection type, and the frequency band to be detected
A narrow band may be used. In the detection circuit 8, the instantaneous fluctuation of the output signal is
In order to equalize, the detected output level is integrated. product
The divided and averaged output levels are output from the comparator 10.
The value is compared with the value in the force reference value table 11. Output reference value
The cable 11 has a pre-measured, output designating circuit 1
Detects when the transmission power indicated by 4 is transmitted correctly
The value of the output level to be detected by road 8 is recorded
I have. The comparison circuit 10 outputs the output level and the reference value table 1.
A comparison with the value of 1 is performed and a comparison result is output. The output comparison result is a variable attenuator control circuit.
Path 42 and the variable attenuator control circuit 42
The variable attenuator 41 approaches the target output value based on the result.
The feedback control is performed as follows. Thus, the implementation of this implementation
In the form, more accurate output control is possible, and
Frequency characteristics have already been corrected for all gains.
Therefore, the output to be detected appears correctly in accordance with the gain.
Therefore, stable feedback control becomes possible. Sixth Embodiment FIG. 12 shows a variable gain control device according to a sixth embodiment of the present invention.
FIG. 3 is a diagram showing a configuration of the device. In this embodiment, the transmission output is
For multiple frequencies in the operating frequency band,
And the frequency of the transmission output.
Feedback of the error of the characteristic
For more accurate frequency response improvement by re-correcting
Things. The same components as those in FIGS. 9 and 11 are the same.
The reference numerals are given and the description of the overlapping portions is omitted. In FIG. 12, a variable gain control device is used.
The transmitter is further added to the variable gain control device of FIG.
Detect the amplitude of each signal component for a number of frequencies
Detection circuit 70 (detection means), integrating each frequency,
Consisting of a plurality of integrating circuits f1 to fn for performing equalization
An integrating circuit 71 for comparing a frequency with a reference value for each frequency;
Comparison circuit 72 including a number of comparison circuits f1 to fn
(Comparing means) and each of the comparing circuits f1 to fn.
A reference value table 73 for supplying a reference value is provided.
You. The comparison result of the comparison circuit 72 is based on the frequency characteristic control.
Circuit 63, variable amplifier control circuit 12, and variable attenuator control
It is output to the control circuit 42. The detection circuit 70 is, for example, an FFT analyzer
Each of multiple frequencies in the used frequency band
The amplitude of the signal component is detected. Detected by the detection circuit 70
Signal components for multiple frequencies
In order to eliminate the movement, the integrating circuit 71
Then, integration and averaging are performed. The integrated and averaged signal is
A comparison circuit 72 compares the frequency with a reference value for each frequency.
You. The reference value table 73 stores in advance
When transmitted at the output specified by the force specifying circuit 14,
The value to be detected by the detection circuit 70 for each frequency is
Has been recorded. In the comparison circuit 72, each of the integrated and averaged
Each frequency is compared with the value from reference value table 73 to
The comparison result for each frequency is output to each circuit unit. Ma
In the frequency characteristic control circuit 63, the
For example, based on the comparison result for each frequency
When the wave number characteristic correction circuit 62 has the configuration shown in FIG.
Update the control signal by changing the locating coefficients Co to Cm
And the frequency characteristic is re-corrected by the frequency characteristic correction circuit 62.
Control to do. Further, when output correction is required as a whole
The variable amplifier control circuit 12 and the variable attenuator control circuit 4
The comparison result is also output to No. 2 to perform gain correction control.example
If the frequency characteristics are re-corrected,
Through the detection circuit 70 and the integration circuit 71
If there is an error with the output value,
From the comparison circuit 72 to the variable amplifier control circuit 42
Output to the variable attenuator control circuit 12. Variable amplifier control times
The path 42 and the variable attenuator control circuit 12 respond to the signal.
Adjust the gain of the variable gain amplifier and variable attenuator, respectively.
A control signal is generated to perform control. Re-compensation of frequency characteristics
After the output, the outputs of the comparison circuits f1 to fn have substantially the same level.
, The output from the comparison circuit 72 is
Can be used, but the average of all outputs
May be used.Thus, in the present embodiment,
By detecting and comparing output signals for each frequency of
Error of frequency characteristics can be detected accurately, and
By re-correcting the frequency response from the result of
Output control can be performed. Further, before the antenna output, the frequency characteristic
Since the detection and correction of
Not only power but also a mask on the frequency axis
In some systems, as described in FIG.
The output power specified for each number cannot be exceeded.
No. Seventh Embodiment FIG. 13 shows a variable gain control device according to a seventh embodiment of the present invention.
FIG. 3 is a diagram showing a configuration of the device. This embodiment is simpler.
The detector enables accurate correction of frequency characteristics.
is there. The same components as those in FIG.
The description of the parts is omitted. In FIG. 13, reference numeral 80 denotes digital data.
DDS to modulate, DDS80 is a digital circuit
, Which transmits and stops modulated waves in a time-division manner.
A controller 81 (signal transmitting means) is provided. 82 is
Converter 83, VCO 83, modulator 81,
Band Test for Controlling Converter 82 and VCO 83
It is a signal control circuit (narrow band test signal control means). The variable gain control constructed as described above will now be described.
The operation of the control device will be described. FIG. 14 shows the narrowband test signal and
FIG. 15 shows a time relationship with the modulated wave, and FIG.
Figure showing the relationship between the test signal and the modulated wave on the frequency axis.
is there. FIG. 16 shows the operation timing of the integrator.
FIG. 14 shows operation timings of the integration circuit 71. In FIG. 13, a modulator 81 is time-divisionally multiplexed.
Transmits and stops modulated waves. Narrow band test signal control circuit 8
4 is a period during which the modulated wave is not transmitted from the modulator 81,
CO83 narrow band any carrier signal in use frequency band
Output from the up-converter 82 as an area test signal.
Control. The selection of the carrier frequency depends on the frequency band used.
Of these, multiple frequencies are selected, and these
It is sent out sequentially for each non-issued period. As a result,
The output of the converter 82 is as shown in FIG.
In this example, n carriers are selected as test signals.
You. During the transmission period of the modulated wave, the modulated wave shown in FIG.
Is sent out. During the period when the modulated wave is not transmitted,
One of the plurality of carriers shown in FIG. 15 is transmitted.
Carriers are always sent in order of frequency
No need. After demultiplexing by the demultiplexer 6, the signal is detected by the detection circuit 70.
The output that is output is the carrier that is the test signal.
Only when the integration circuit 71 integrates and averages each frequency
Be converted to The operation timing of the integration circuit 71 is shown in FIG.
Is done. The integrating circuit 71 stores the product for each frequency of the test signal.
The narrow band test signal control circuit 84
While instructing the transmission of the signal,
Only the corresponding integrator is selected and the carrier signal is sent out.
Only during this period, the output signal of the detection circuit 70 is integrated.
U. The output averaged by each integrator of the integrating circuit 71
The force is output by the comparison circuit 72 for each frequency.
If the transmission output indicated by the designating circuit 14 was correctly transmitted
Of the output level to be detected by the detection circuit 70 when
The output is fed to the frequency characteristic control circuit 63 or the like.
Back. As described above, during a series of transmissions, the carrier signal
Alternately and sequentially, detecting, comparing by frequency,
By performing feedback, more accurate correction of frequency characteristics can be performed.
It can be carried out. In this embodiment, the detection circuit
70 is power without a frequency detection function such as a detection diode
The detection type can also be realized. The variable gain control according to each of the above embodiments
In the control device, this is an example applied to the transmission unit of a wireless transmitter.
However, if it automatically adjusts the gain of the input / output signal,
Such as wireless and wired transmission.
Receiver, repeater, TV video detection circuit, or temperature control
It can be applied to the gain adjustment section of various control devices such as control devices.
Needless to say. In particular, such as CDMA, OFDM, etc.
Radio that communicates using a broadband frequency band at one time
It is suitable for application to a gain control device used in a communication device.
You. In the above embodiment, the variable gain control
The names of the devices are used for convenience of explanation.
For example, an automatic gain control device, an AGC device, etc.
Also, even if it is built into a part of communication device etc.
Good. In the above embodiment, the frequency characteristic compensation
A hyper circuit capable of changing the frequency characteristic of the positive circuit 21
Combination of multiple circuits, notch circuits, low-pass circuits, etc.
The filter type, filter combination,
The number of stages (order) of the filter is arbitrary. In addition,
The modulator, control circuit, and correction table that constitute the variable gain control device
The types and number of bulls and the like are limited to the above-described embodiments.
Absent. [0081] As described in detail above, according to the present invention,
The same time in all desired variable gain ranges
Accurate output control with broadband frequency characteristics
It can be carried out. Specifically, obtain the following effects
Can be. In the variable gain control device according to claim 1,
Gain control with broadband frequency characteristics at
It will work. In addition, the frequency characteristics at the same time are flat.
Transmit wideband signals with low distortion.
Can be In the variable gain control device according to claim 2,
More accurate gain control and simplification of gain correction means
Can be. In the variable gain control device according to claim 3,
Accurate gain control, especially for digital circuits in the modulator
To integrate with the digital part when using
Thus, the circuit can be simplified. In the variable gain control device according to the fourth aspect, the frequency
Accurate while reducing the load and time involved in correcting wavenumber characteristics
Has the effect that gain control over a wide band can be realized.
You. In the variable gain control device according to claim 5, the detected
By comparing the values and performing feedback control,
The effect is that stable and accurate gain control can be realized.
You. In the variable gain control device according to claim 6,
Stable gain control while maintaining accurate and broadband frequency characteristics
And transmit the transmitted signal without distortion.
it can. In the variable gain control device according to claim 7, the frequency
Stable gain control while simplifying the characteristic detection means
And can transmit the transmitted signal without distortion.
Wear.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a configuration of a variable gain control device according to a first embodiment of the present invention. FIG. 2 is a diagram showing how the gain and frequency characteristics of the variable gain control device according to the present embodiment are corrected. FIG. 3 is a diagram illustrating a configuration example of a frequency characteristic correction circuit of the variable gain control device according to the present embodiment, and a gain and a frequency characteristic corresponding to each component. FIG. 4 is a diagram illustrating a configuration example of a variable low-pass filter of the variable gain control device according to the present embodiment. FIG. 5 is a diagram illustrating an example of a configuration of a frequency characteristic correction circuit of the variable gain control device according to the present embodiment. FIG. 6 is a diagram illustrating a configuration of a variable gain control device according to a second embodiment of the present invention. FIG. 7 is a diagram showing how the gain and frequency characteristics of the variable gain control device according to the present embodiment are corrected. FIG. 8 is a diagram illustrating a configuration of a variable gain control device according to a third embodiment of the present invention. FIG. 9 is a diagram illustrating a configuration of a variable gain control device according to a fourth embodiment of the present invention. FIG. 10 is a diagram illustrating an example of a configuration of a frequency characteristic correction circuit of the variable gain control device according to the present embodiment. FIG. 11 is a diagram illustrating a configuration of a variable gain control device according to a fifth embodiment of the present invention. FIG. 12 is a diagram illustrating a configuration of a variable gain control device according to a sixth embodiment of the present invention. FIG. 13 is a diagram illustrating a configuration of a variable gain control device according to a seventh embodiment of the present invention. FIG. 14 is a diagram illustrating a time relationship between a narrowband test signal and a modulated wave in the variable gain control device according to the present embodiment. FIG. 15 is a diagram illustrating a relationship on a frequency axis between a narrowband test signal and a modulated wave in the variable gain control device according to the present embodiment. FIG. 16 is a diagram illustrating the operation timing of the integrator of the variable gain control device according to the present embodiment. FIG. 17 is a diagram showing a configuration of a conventional variable gain control device of a transmitter. FIG. 18 is a diagram showing a relationship between a control signal of a variable gain amplifier of a conventional variable gain control device and its gain. FIG. 19 is a diagram showing a change in frequency characteristics at each gain of a variable gain amplifier of a conventional variable gain control device. FIG. 20 is a diagram showing the relationship between the output regulation of power on the frequency axis and the output spectrum of the conventional variable gain control device. [Description of Signs] 1, 51, 61, 81 Modulator 2, 82 Upconverter 3, 83 VCO 4 Variable Gain Amplifier 5 Bandpass Filter 6 Demultiplexer (Demultiplexer) 7 Antenna 8, 70 Detection Circuit (Detector) 9, 71 Integrating circuit 10, 72 Comparing circuit (comparing means) 11, 73 Reference value table 12 Variable gain amplifier control circuit (Variable gain amplifier controlling means) 13, 23, 43, 55, 64 Correction table 14 Output designating circuit 21 , 62 Frequency characteristic correction circuit (frequency characteristic correction means) 22, 63 Frequency characteristic control circuit (frequency characteristic control means) 31 Low pass filter (LPF) 32 Notch filter (Notch Filter) 33 High pass filter (HPF) 34 Variable capacitance element 35 Delay Element 36 Weighting coefficient 37 Adder 38 Switch 41 Variable attenuator (variable gain means) 42 Variable attenuator control circuit (variable gain control means) 50, 60, 80 DDS 52 Variable gain circuit (variable gain means) 53 D / A converter 54 Variable gain control circuit (variable gain control means) 84 Narrow band test signal control circuit ( Narrow band test signal control means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H03G 3/10 H03G 3/30 H04B 1/04

Claims (1)

(57) Claims: 1. A variable gain amplifier capable of changing a gain, and controlling the variable gain amplifier to have a desired gain.
Variable frequency control on the frequency axis at the same time as the variable amplifier control means
Frequency characteristic correction means, and a frequency characteristic corresponding to each gain of the variable gain amplifier
Means for holding correction data for correcting the frequency characteristic,
To control the frequency characteristic correction means so as to correct
Wave number characteristic control means, demultiplexing means for demultiplexing an output signal, detection means for detecting the demultiplexed output signal, and a ratio for comparing a value detected by the detection means with a predetermined value
Comparing means, a signal transmitting means capable of transmitting a modulated wave and a narrow-band test signal in a time- division manner, and a narrow-band test signal control means for designating a transmission frequency of the narrow-band test signal and its timing. The signal transmitting means, for each period during which the modulated wave is not transmitted,
The narrow-band test signal is sequentially transmitted at the transmission frequency instructed by the narrow-band test signal control unit, and the comparison unit transmits the narrow-band test signal at the corresponding frequency for each frequency of the narrow-band test signal. Period, while collecting output results from the detection means, comparing the value collected for each frequency with a predetermined value for each frequency to obtain a target output, and outputting a comparison result; The frequency characteristic control means performs feedback control for correcting frequency correction control based on the comparison result for each frequency, and the variable amplifier control means or at least one of the variable gain control means controls the comparison. variable gain control you and performs feedback control to correct the gain control based on the output of means.