WO2011087149A1

WO2011087149A1 - Amplification device with automatic gain control, automatic gain control device, and automatic gain control method

Info

Publication number: WO2011087149A1
Application number: PCT/JP2011/051032
Authority: WO
Inventors: 太郎寺本
Original assignee: 日本電気株式会社
Priority date: 2010-01-18
Filing date: 2011-01-14
Publication date: 2011-07-21

Abstract

Disclosed is an automatic gain control device which can revert to a normal state when a malfunction occurs. The device is provided with: a gain control means which sets a designated gain for a variable gain amplification device, which amplifies an input signal at a designated gain between a minimum gain and a maximum gain and outputs an output signal, so that the signal level of the output signal lies within a predetermined range; and a malfunction detection means which outputs a malfunction detection signal when the occurrence of a malfunction in the gain control means is detected, and resets the gain control means.

Description

Automatic gain control amplification device, automatic gain control device, and automatic gain control method

The present invention relates to an automatic gain control amplification device, an automatic gain control device, and an automatic gain control method, and more particularly to an automatic gain control amplification device, an automatic gain control device, and an automatic gain control method that can cope with an abnormality.

Automatic gain control for automatically adjusting the level of a signal is often performed for an amplifier such as a communication device.
The automatic gain control is described in Patent Document 1, for example. The automatic gain control device of Patent Document 1 includes a variable gain amplifier (hereinafter referred to as “VGA”) and a power calculator. Then, the gain of the VGA is controlled so that the signal power after the automatic gain control falls between the upper limit value and the lower limit value of the target power value width.

JP 2001-69066 A (page 5-6, FIG. 2)

In the automatic gain control amplifier, the gain control signal for controlling the gain of the VGA may stick to a state where the gain of the VGA is controlled to the maximum value or a state where the gain is controlled to the minimum value for some reason. FIG. 8 shows an example of the state of the gain control signal when an abnormality occurs in the automatic gain control amplification device. FIGS. 8A and 8B show a case where the gain control signal sticks to the minimum value and the maximum value at time t0, respectively.
As shown in FIG. 8, an abnormality occurs in the automatic gain control amplifying apparatus, and even if the output of the VGA reaches the maximum value, the gain is not controlled to decrease, or even if the output of the VGA becomes the minimum value, May not be controlled in the direction of increasing In this way, control in the reverse direction is applied to control of increase or decrease of the gain that should be originally performed, and automatic gain control may be disabled. In such a case, the output signal of the VGA, that is, the output signal of the automatic gain control amplifier becomes a signal amplified with the maximum gain or the minimum gain, and the signal level does not become the signal level that should be originally intended. Therefore, there is a high possibility that the subsequent circuit cannot operate correctly.
However, the automatic gain control amplifier of Patent Document 1 does not include means for detecting an abnormal situation. Therefore, the technique of Patent Document 1 cannot cope with a case where an abnormality occurs in the automatic gain control amplifier.
(Object of invention)
The present invention has been made in view of the technical problems as described above, and provides an automatic gain control amplification device, an automatic gain control device, and an automatic gain control method capable of restoring a normal state when an abnormality occurs. The purpose is to do.

The automatic gain control amplifying apparatus of the present invention amplifies an input signal with a specified gain that is set to be equal to or higher than the minimum gain and lower than the maximum gain, and outputs the output signal. A gain control means for setting the designated gain so as to be within a range; and an abnormality detection means for outputting an abnormality detection signal and initializing the gain control means when detecting that an abnormality has occurred in the gain control means, It is characterized by providing.
An automatic gain control device according to the present invention includes a variable gain amplifying device that amplifies an input signal with a specified gain that is set to be equal to or greater than a minimum gain and equal to or less than a maximum gain, and the signal level of the output signal is within a predetermined range. A gain control means for setting the designated gain so that the abnormality is detected, and an abnormality detection means for outputting an abnormality detection signal and initializing the gain control means when it is detected that an abnormality has occurred in the gain control means. It is characterized by.
In the automatic gain control method of the present invention, a specified gain set to be equal to or higher than the minimum gain and lower than or equal to the maximum gain is set in a variable gain amplifying apparatus that amplifies an input signal and outputs an output signal, and the signal level of the output signal is A designated gain is set so as to be within a predetermined range, and when a set gain is set, it is detected that an abnormality has occurred, and when an abnormality is detected, a setting process for setting the set gain is initialized.

The automatic gain control amplifying apparatus, automatic gain control apparatus, and automatic gain control method of the present invention have the effect of being able to recover to a normal state when an abnormality occurs.

It is a block diagram which shows the structure of the automatic gain control amplification apparatus of the 1st Embodiment of this invention. It is a block diagram which shows the structure of the modification of the automatic gain control amplification apparatus of the 1st Embodiment of this invention. It is a block diagram which shows the structure of the automatic gain control apparatus of the 1st Embodiment of this invention. It is a block diagram which shows the structure of the modification of the automatic gain control apparatus of the 1st Embodiment of this invention. It is a block diagram which shows the structure of the automatic gain control amplification apparatus of the 2nd Embodiment of this invention. It is a graph which shows the example of the change of a gain control signal when abnormality generate | occur | produces in the automatic gain control amplification apparatus of the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the automatic gain control amplification apparatus of the 3rd Embodiment of this invention. It is a graph which shows the example of the state of the signal which controls the gain of a variable gain amplifier when abnormality arises in an automatic gain control amplifier.

(First embodiment)
The variable gain control amplifying apparatus of this embodiment will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the variable gain control amplifying apparatus of this embodiment. The variable gain control amplification device according to the present embodiment includes a variable gain amplification unit 101, a gain control unit 102, and an abnormality detection unit 103.
The variable gain amplifying unit 101 amplifies the input signal 104 with a gain specified by the gain control signal 106 output by the gain control unit 102 (hereinafter referred to as “specified gain”), and outputs an output signal 105. As the designated gain, a minimum value (hereinafter referred to as “minimum gain”) and a maximum value (hereinafter referred to as “maximum gain”) are set.
The gain control unit 102 performs the automatic gain control described above. That is, the designated gain is set so that the signal level of the output signal 105 falls within a predetermined range, and the gain control signal 106 corresponding to the designated designated gain is output. Specifically, the designated gain is decreased when the signal level of the output signal 105 is greater than a predetermined range, and the designated gain is increased when the signal level of the output signal 105 is smaller than the predetermined range. The specific content of the automatic gain control is not important to the spirit of the present invention. Moreover, those skilled in the art can easily realize automatic gain control using various methods. Therefore, detailed description of automatic gain control is omitted. As described above, even when the signal level of the input signal 104 varies due to the automatic gain control by the gain control unit 102, the signal level of the output signal 105 falls within a predetermined range.
The abnormality detection unit 103 detects that an abnormality has occurred in the gain control unit 102 and outputs an abnormality detection signal 107. A method of detecting that an abnormality has occurred in the gain control unit 102 is not particularly limited. In the present embodiment, the abnormality detection unit 103 monitors the change in the designated gain by observing the gain control signal 106 output by the gain control unit 102. When the change in the designated gain satisfies a predetermined condition, it is determined that an abnormality has occurred in the gain control unit 102, and an abnormality detection signal 107 is output.
The gain control unit 102 initializes the gain control unit 102 when the abnormality detection signal 107 is output. The initialized gain control unit 102 starts a designated gain calculation process based on the signal level of the output signal 105 at that time. At this time, the gain control unit 102 may once set a predetermined initial gain that is larger than the minimum gain and smaller than the maximum gain.
Various conditions can be set as conditions for determining that an abnormality has occurred in the gain control unit 102 based on the designated gain.
For example, the fact that the specified gain remains at the maximum gain or the minimum gain for a predetermined period and becomes a constant value can be used as a condition for determining the occurrence of an abnormality in the gain control unit 102. That is, when detecting that the gain control signal 106 remains at a level corresponding to the maximum value of the designated gain for a predetermined period, the abnormality detection unit 103 outputs the abnormality detection signal 107. Alternatively, when detecting that the gain control signal 106 remains at a level corresponding to the minimum value of the designated gain for a predetermined period, the abnormality detection unit 103 outputs an abnormality detection signal 107.
Alternatively, by monitoring the output signal 105, the occurrence of an abnormality in the gain control unit 102 can be detected indirectly. FIG. 2 is a block diagram showing a modification of the configuration of the variable gain control amplifying apparatus of the present embodiment.
When monitoring the output signal 105, the abnormality detection unit 103 analyzes the output signal 105 to acquire predetermined information, and detects the occurrence of an abnormality in the gain control unit 102 based on the content of the information.
For example, the abnormality detection unit 103 may detect the occurrence of an abnormality in the set gain using a carrier power to noise ratio (Carrier to Noise Ratio, hereinafter referred to as “C / N”). For example, when detecting that the C / N of the output signal 105 is equal to or less than a predetermined value, the abnormality detection unit 103 determines that the set gain is set to an abnormal value and an abnormality has occurred in the gain control unit 102. Then, the abnormality detection signal 107 is output.
Alternatively, when a predetermined signal that should be included in the output signal 105 cannot be detected, it may be determined that an abnormality has occurred in the gain control unit 102. For example, the output signal 105 may include a synchronization signal for use in a subsequent circuit. At this time, the abnormality detection unit 103 tries to extract the synchronization signal, and outputs the abnormality detection signal 107 if the synchronization signal cannot be extracted.
Note that this embodiment can also be applied to an automatic gain control device that does not include the variable gain amplification unit 101 and performs gain control on an external variable gain amplification device. 3 and 4 are block diagrams showing the configuration of the automatic gain control apparatus. The automatic gain control devices of FIGS. 3 and 4 include only the gain control unit 102 and the abnormality detection unit 103 of the automatic gain control amplifiers of FIGS. 1 and 2, respectively. An output signal 105 from an external variable gain amplifying device (not shown) is input, and a gain control signal 106 is output to the external variable gain amplifying device. The functions of the gain control unit 102 and the abnormality detection unit 103 are the same as those of the automatic gain control amplifier gain control unit 102 and the abnormality detection unit 103 of FIGS.
As described above, the automatic gain control amplification apparatus according to the present embodiment detects that an abnormality has occurred in the gain control unit, and initializes the gain control unit. Therefore, when an abnormality occurs in the gain control unit, the automatic gain control device can be restored to a normal state.
The present embodiment can be applied to all devices that perform automatic gain control. In other words, the present invention can be applied regardless of whether the signal processing for detecting the occurrence of abnormality is analog processing or digital processing. Further, this embodiment does not depend on the frequency band of the signal to be amplified. Furthermore, this embodiment may include other circuits such as a modulator / demodulator and a frequency converter in addition to the amplifier to be processed for automatic gain control.
(Second Embodiment)
Next, an embodiment in which the present invention is applied to a specific automatic gain control amplifying apparatus will be described with reference to the drawings. FIG. 5 is a block diagram showing a configuration of an automatic gain control amplifying apparatus according to the second embodiment of the present invention. In the following description of the embodiments, a quadrature modulation scheme such as QPSK (Quadrature Phase Shift Keying) or QAM (Quadrature Amplitude Modulation) is assumed as a modulation scheme, and a synchronous detection scheme is assumed as a detection scheme of a demodulator. The components of two orthogonal baseband signals are denoted as Ich and Qch.
The automatic gain control amplifying apparatus of this embodiment includes a VGA 301, a quadrature demodulator 302, an oscillator 303, an analog-digital converter (hereinafter simply referred to as “A / D”) (Ich) 304, and an A / D (Qch) 305. , An automatic gain control (Automatic Gain Control; hereinafter referred to as “AGC”) circuit 310. The AGC circuit 310 includes a power calculation circuit 306, a comparator 307, a low pass filter (hereinafter referred to as “LPF”) 308, and a specified value monitoring circuit 309.
The VGA 301 amplifies an intermediate frequency input signal (IFIN) signal 311 that is an input signal according to a designated value designated by the gain control signal 325 and outputs an IFIN signal 312. A specific method for controlling the gain of the VGA 301 by the gain control signal 325 is not particularly limited. For example, the gain of the VGA 301 may be reduced if the specified value of the gain control signal 325 is reduced, and the gain may be increased if the specified value of the gain control signal 325 is increased. Conversely, the gain may be increased if the specified value of the gain control signal 325 is decreased, and the gain may be decreased if the specified value of the gain control signal 325 is increased.
The quadrature demodulator 302 converts the IFIN 312 into an analog baseband signal Ich 314 and an analog baseband signal Qch 315 that are orthogonal to each other using the reference frequency signal 313 from the oscillator 303.
The A / D (Ich) 304 converts the analog baseband signal Ich 314 into a digital baseband signal Ich 316 in order to perform the subsequent processing by digital processing. Similarly, the A / D (Qch) 305 converts the analog baseband signal Qch315 to a digital baseband signal Qch317. The sampling period of A / D (Ich) 304 and A / D (Qch) 305 (hereinafter referred to as “A / D sampling period”) is set to an appropriate value in consideration of the required AGC responsiveness. The
Next, each circuit in the AGC circuit 310 will be described. In the present embodiment, the AGC circuit 310 performs AGC. “AGC” means that the power value 318 is controlled to converge to the set AGC threshold 319. Specifically, the AGC absorbs the fluctuation of the input IFIN 311 by controlling the gain of the VGA 301, and the digital baseband signal obtained from the A / D (Ich) 304 and A / D (Qch) 305 It is said that the power is controlled so as to be a constant value.
The power calculation circuit 306 calculates the power possessed by the digital baseband signal Ich316 and the digital baseband signal Qch317. That is, the digital baseband signal Ich 316 and the digital baseband signal Qch 317 are squared, their sum is calculated, and output as a power value 318. The calculation of the power value 318 is performed every A / D sampling period. Therefore, the power value 318 is output for each A / D sampling period in time series.
The comparator 307 compares the power value 318 with the AGC threshold value 319 set from the outside, and outputs 1 or 0 as the comparator output 320 according to the comparison result. For example, 1 is output if the power value 318 is smaller than the AGC threshold value 319, and 0 is output if it is larger. On the contrary, 0 may be output if the power value 318 is smaller than the AGC threshold 319, and 1 may be output if it is larger. The comparison operation by the comparator 307 is also performed every A / D sampling period. Accordingly, the comparison value output 320 is also output for each A / D sampling period in time series.
The LPF 308 removes the high frequency component of the comparator output 320 that is output every A / D sampling period, and outputs an LPF output 321. For example, the LPF output 321 approaches the minimum value when the ratio of “0” in the value of the comparator output 320 output in time series is large, and the LPF output 321 when the ratio of “1” is large. Approaches the maximum value. Further, the LPF 308 is reset by an AGC reset signal 324 input from the designated value monitoring circuit 309 described later. “LPF 308 is reset” means, for example, that the circuit of LPF 308 is reset to a predetermined initial state. The reset LPF 308 restarts the filtering process from the initial state.
The designated value monitoring circuit 309 compares the LPF output 321 with the designated value upper limit value 322 and the designated value lower limit value 323 set from the outside. When the LPF output 321 continues for a certain period of time (hereinafter referred to as “abnormality determination time”) that is greater than the specified value upper limit value 322 or smaller than the specified value lower limit value 323, the AGC reset signal 324. Is output to reset the AGC operation.
In the present embodiment, the number of occurrences when the AGC reset signal 324 is continuously generated is also counted. That is, the AGC operation is reset, and the number of times the AGC reset signal 324 is generated is counted again immediately after the AGC has once returned to normal. When the count value exceeds a certain number of times (hereinafter referred to as “failure determination number”), it is determined that the AGC amplifying device has failed, and an alarm signal 326 is generated.
The above is the function and operation of each block inside the AGC amplifying apparatus of this embodiment. Next, the overall operation of the AGC amplification apparatus according to this embodiment will be described.
When the AGC is operating normally, the LPF output 321 is output as a gain control signal 325 for controlling the gain of the VGA 301 as it is. That is, when the time when the LPF output 321 becomes the specified value upper limit value 322 or more or the specified value lower limit value 323 or less does not exceed the abnormality determination time, the gain of the VGA 301 is controlled by the LPF output 321.
However, as shown in FIG. 8, when the LPF output 321 for controlling the gain of the VGA sticks to the maximum value or the minimum value due to some cause, the normal AGC amplifier cannot be restored by itself.
Therefore, in the AGC amplifying apparatus of this embodiment, the designated value monitoring circuit 309 is used to monitor the LPF output 321. The designated value monitoring circuit 309 compares the LPF output 321 with the designated value upper limit value 322 and the designated value lower limit value 323. When the LPF output 321 is greater than the specified value upper limit value 322 or smaller than the specified value lower limit value 323, the AGC reset signal 324 is output when the LPF output 321 continues for more than the abnormality determination time. The LPF 8 is reset by the AGC reset signal 324, and the AGC is initialized. FIG. 6 shows an example of a change in the gain control signal when an abnormality occurs in the AGC amplification apparatus according to this embodiment. 6A and 6B show cases where the gain control signal sticks to the minimum value and the maximum value at time t0, respectively. Since the AGC reset signal 324 is generated at time t1, the AGC recovers to the normal state, and the gain control signal 325 converges to the normal level.
As described above, the designated value monitoring circuit 309 detects that the gain control signal 325 is stuck to the maximum value or the minimum value for some reason by monitoring the LPF output 321. When the AGC becomes uncontrollable, the designated value monitoring circuit 309 can initialize the AGC operation by resetting the LPF 308 using the AGC reset signal 324. Therefore, it is not necessary to detect an abnormality of the AGC amplifying apparatus in a circuit subsequent to the AGC amplifying apparatus, and the operation of the AGC can be stabilized. Further, since the AGC operation does not depend on the performance of the abnormality detection circuit in the subsequent stage, it can be expected that the time for the signal to pass through the AGC amplifying apparatus is shortened.
Even when IFIN 311 outside the AGC control range is input to the AGC amplifying apparatus, the gain control signal 325 sticks to the maximum value or the minimum value, and the AGC operation is not normally performed. Therefore, the AGC operation is not normally performed no matter how many times the AGC operation is initialized. In order to cope with such a case, the number of times the AGC reset signal 324 is generated may be counted. Then, when the count value exceeds the number of times of failure determination, it is determined that the input is excessive or insufficient, and an alarm signal 326 indicating that the AGC amplifier has failed may be generated.
As described above, the AGC amplifying apparatus according to the present embodiment uses the signal output from the designated value monitoring circuit 309 when the signal for controlling the gain of the VGA sticks to the maximum value or the minimum value and the AGC is disabled. The operation can be reset.
Therefore, when an abnormality occurs in the AGC amplifier, there is an effect that it can be restored to a normal state. Further, it is not necessary to generate various alarm signals in the subsequent circuit of the AGC amplifier. Therefore, the circuit configuration can be simplified and the AGC operation can be stabilized. Further, as shown in FIG. 6, since the convergence of AGC can be accelerated, there is an effect of shortening the time for the signal to pass through the AGC amplifying apparatus.
(Third embodiment)
Next, an embodiment obtained by modifying a part of the second embodiment will be described with reference to the drawings. FIG. 7 is a block diagram showing the configuration of the AGC amplification apparatus according to the second embodiment of the present invention.
The AGC amplification apparatus according to the third embodiment includes a VGA 301, a quadrature demodulator 302, an oscillator 303, an A / D (Ich) 304, and an A / D (Qch) 305. Furthermore, the AGC amplification apparatus according to the third embodiment includes a power calculation circuit 306, a comparator 307, an LPF 328, a C / N estimation circuit 329, and a frame synchronization circuit 330.
The operations of the VGA 301, the quadrature demodulator 302, the oscillator 303, the A / D (Ich) 304, and the A / D (Qch) 305 and the functions of the signals input and output by these are described in the AGC of the second embodiment shown in FIG. Since it is the same as that of the amplifying apparatus, the description is omitted.
Further, the operations of the power calculation circuit 306 and the comparator 307 and the functions of the signals input and output by these are the same as those of the AGC amplification apparatus of the second embodiment shown in FIG.
The AGC amplifier according to the third embodiment includes an AGC circuit 327 that is different from the AGC circuit 310 of the AGC amplifier according to the second embodiment. That is, the AGC circuit 327 includes an LPF 328 having a function different from that of the LPF 308, a C / N estimation circuit 329 and a frame synchronization circuit 330 that the AGC circuit 310 does not have.
The LPF 328 removes the high-frequency component of the comparator output 320 that is output in time series for each A / D sampling period, and outputs a gain control signal 325 in the same manner as the LPF 308. For example, the gain control signal 325 approaches the minimum value when the ratio of “0” in the value of the comparator output 320 that is the input signal of the LPF 328 is large, and the gain control signal when the ratio of “1” is large. 325 approaches the maximum value.
Similarly to the LPF 308, the LPF 328 also has a reset function. That is, the LPF 328 is reset by a C / N alarm signal 331 or a frame asynchronous signal 332 described later. The reset function of the LPF 328 is the same as that of the LPF 308.
The C / N estimation circuit 329 receives the digital baseband signal Ich316 and the digital baseband signal Qch317, and estimates the C / N of the digital baseband signal. When the estimated C / N is smaller than a predetermined reference value, a C / N alarm signal 331 is output.
The frame synchronization circuit 330 receives the digital baseband signal Ich316 and the digital baseband signal Qch317, and extracts a frame synchronization signal from the digital baseband signal. The frame synchronization signal is a timing signal that is included in IFIN 311 and indicates the beginning of a frame for processing in units of frames. The frame synchronization circuit 330 outputs a frame asynchronous signal 332 when the frame synchronization signal cannot be extracted from the digital baseband signal Ich316 and the digital baseband signal Qch317.
Similar to the second embodiment, also in the AGC amplifying apparatus of the present embodiment, the gain control signal 325 for controlling the gain of the VGA 301 may stick to the maximum value or the minimum value for some reason. At that time, since AGC becomes uncontrollable, the received IFIN signal 311 is not demodulated correctly.
Therefore, in the present embodiment, the AGC operation is initialized using the reset signal generated by the circuit that inputs the digital baseband signal Ich316 and the digital baseband signal Qch317. In the present embodiment, an alarm signal such as the C / N alarm signal 331 or the frame asynchronous signal 332 is used as the reset signal.
Alternatively, the AGC operation may be reset using an AGC macro reset signal 333 that initializes the AGC circuit 327 itself. Then, after the AGC circuit 327 is initialized, the AGC may be re-controlled and the received signal may be demodulated.
As described above, the AGC amplifying apparatus according to the present embodiment detects the occurrence of an abnormality in the AGC circuit 327 based on the digital baseband signal Ich316 and the digital baseband signal Qch317 that are output signals of the AGC amplifying apparatus. When the above occurrence is detected, a reset is generated and the AGC operation is reset. Therefore, when an abnormality occurs in the AGC amplifier, there is an effect that it can be restored to a normal state.
In the present embodiment, both the C / N estimation circuit 329 and the frame synchronization circuit 330 are provided, but it goes without saying that the AGC can be initialized even if only one of them is provided.
In the second embodiment and the third embodiment, the synchronous detection method is assumed as the detection method of the demodulator, but the detection method is not limited to the synchronous detection method. The present embodiment can also be applied to other detection methods, for example, an AGC amplifier that employs a quasi-synchronous detection method.
In addition, each of the above embodiments can be combined with other embodiments.
While the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.
This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2010-008073 for which it applied on January 18, 2010, and takes in those the indications of all here.

The present invention relates to an automatic gain control amplification device, an automatic gain control device, and an automatic gain control method, and more particularly to an automatic gain control amplification device, an automatic gain control device, and an automatic gain control method that can cope with an abnormality. Have industrial applicability.

104 Input signal 105 Output signal 106 Gain control signal 107 Anomaly detection signal 303 Oscillator 310 Automatic gain control (AGC)

circuit

311, 312 Intermediate frequency input signal (IFIN) signal 313 Reference frequency signal 314 Analog baseband signal Ich
315 Analog baseband signal Qch
316 Digital baseband signal Ich
317 Digital baseband signal Qch
318 Power value 319 AGC threshold 320 Comparator output 321 LPF output 322 Specified value upper limit 323 Specified value lower limit 324 AGC reset signal 325 Gain control signal 326 Alarm signal 327 AGC circuit 331 C / N alarm signal 332 Frame asynchronous signal 333 AGC macro・ Reset signal

Claims

Variable gain amplifying means for amplifying an input signal with a specified gain set to be equal to or higher than the minimum gain and lower than the maximum gain, and to output an output signal;
Gain control means for setting the designated gain so that the signal level of the output signal is within a predetermined range;
When detecting that an abnormality has occurred in the gain control means, an abnormality detection means for outputting an abnormality detection signal and initializing the gain control means;
An automatic gain control amplifying apparatus comprising:
2. The automatic gain control amplifying apparatus according to claim 1, wherein the gain control means sets, as the designated gain, an initial gain that is larger than the minimum gain and smaller than the maximum gain when the initialization is performed.
3. The automatic gain control amplifying apparatus according to claim 1, wherein the abnormality detection unit outputs an abnormality detection signal based on the designated gain and initializes the gain control unit.
4. The automatic gain control according to claim 1, wherein the abnormality detection unit outputs an abnormality detection signal based on the change tendency of the designated gain, and initializes the gain control unit. 5. Amplification equipment.
The abnormality detection means detects the abnormality detection signal when detecting that the specified gain stays at the maximum gain for a predetermined period, or when detecting that the specified gain stays at the minimum gain for the predetermined period. 5. The automatic gain control amplifying device according to claim 4, wherein the automatic gain control amplifying device outputs.
The abnormality detection means outputs the abnormality detection signal when detecting that the carrier power to noise power ratio of the output signal is equal to or less than a predetermined value. The automatic gain control amplifying device described.
4. The automatic gain control amplification device according to claim 1, wherein the abnormality detection means outputs the abnormality detection signal when a predetermined signal to be included in the output signal cannot be extracted.
A variable gain amplifying apparatus that amplifies an input signal with a specified gain that is set to be equal to or greater than the minimum gain and equal to or less than the maximum gain and outputs the output signal to the variable gain amplifying device so that a signal level of the output signal is within a predetermined range. Gain control means to set;
When detecting that an abnormality has occurred in the gain control means, an abnormality detection means for outputting an abnormality detection signal and initializing the gain control means;
An automatic gain control device comprising:
In the variable gain amplifier that amplifies the input signal and outputs the output signal, a specified gain that is set to be equal to or higher than the minimum gain and equal to or lower than the maximum gain is set.
Setting the designated gain so that the signal level of the output signal is within a predetermined range;
Detect that an abnormality has occurred when setting the specified gain,
An automatic gain control method for initializing the setting of the designated gain when the abnormality is detected.
10. The automatic gain control method according to claim 9, wherein when the abnormality is detected, a predetermined initial gain is set as the designated gain when the designated gain is set.
11. The automatic gain control method according to claim 9, wherein an initial gain that is larger than the minimum gain and smaller than the maximum gain when the initialization is performed is set as the designated gain.
12. The automatic gain control method according to claim 9, wherein an abnormality detection signal is output based on the designated gain, and the gain control means is initialized.
13. The automatic gain control method according to claim 9, wherein an abnormality detection signal is output based on the change tendency of the designated gain, and the gain control means is initialized.
The abnormality detection signal is output when it is detected that the specified gain stays at the maximum gain for a predetermined period, or when it is detected that the specified gain stays at the minimum gain for the predetermined period. The automatic gain control method according to claim 13.
13. The automatic gain control method according to claim 9, wherein the abnormality detection signal is output when it is detected that a carrier power to noise power ratio of the output signal is a predetermined value or less. .
13. The automatic gain control method according to claim 9, wherein the abnormality detection signal is output when a predetermined signal to be included in the output signal cannot be extracted.