KR20160092646A - Automatic gain controller and method thereof - Google Patents

Abstract

The present invention relates to an automatic gain controller. According to an embodiment of the present invention, the automatic gain controller comprises: an analog signal gain adjustment part which adjusts a gain of an analog signal input as a set gain value; an analog-to-digital converter which converts the analog signal, which is gain-adjusted in the gain adjustment part, into a digital signal; a gain control signal generation part which measures power of the digital signal and outputs a control signal which controls the gain of the analog signal gain adjustment part according to the power of the digital signal; a memory which stores the gain value of the analog signal gain adjustment part and a gain adjustment time; and a signal gain compensation part which compensates for a gain of the digital signal by using the gain value and the gain adjustment time.

Description

[0001] Automatic gain controller and method [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic gain control apparatus and a method thereof, and more particularly to an automatic gain control technique using past gain compensation after reception.

 One trend of recent development of wireless communication systems is D2D communication. In addition, digital technologies that require gain control in marine communication are being introduced. D2D communication and maritime communication have a common point, that is, the gain control of the received signal is very difficult. When the gain of the received signal is less than the proper level and the received signal is too small for the input to the ADC, the quantization noise of the ADC is seriously increased. Conversely, if the gain is too high, the signal will saturate the ADC and the received signal will be completely destroyed.

Since the conventional automatic gain control is not performed in an instant, it takes time to measure the power of the received signal to some extent. For example, in the case of mobile communication, the base station always transmits a signal in the corresponding frequency band. Therefore, the power of the signal is measured to adjust the gain of the received signal. After that, the signal which is normally ADC is used to perform finer gain control and to perform signal processing necessary for signal reception. However, in the case of D2D communication and maritime communication, the power of the received signal can not be known in advance because the inter-terminal or inter-ship communication is performed mainly without interfering with the base station.

This problem occurs because both the D2D communication and the offshore communication relies on communication between the terminals without depending on the base station. For example, in the case of mobile terminals, the D2D communication is not always in a fixed position, so there is a problem that the path loss between the terminals is not constant. At the same time, in addition to this, it is often difficult to know which terminal is shooting at which slot time or number. Therefore, a signal of a terminal close to me is received with a large power, and a signal of a terminal far from me is received with a small power. The power difference of these received signals is very large, which may cause a difference of more than 70dB.

As with maritime communications, you can not tell which ship will send me a signal at any slot number or time. The difference between the signal from a ship far away from me and the signal from a nearby ship is more than 70dB for a ship 100m away and 200km away.

Particularly, there is a problem that it is difficult to use a conventional automatic gain control method because a terminal (or a ship) signal in a corresponding slot can not be known at a certain power level.

Patent Publication No. KR 2013-0074476

The embodiment of the present invention performs fast automatic gain control at the beginning of each reception slot to rapidly follow the power of the received signal and restore the distortion of the analog digital converter ADC while following the reception power, And an automatic gain control device capable of generating the constant reception signal.

An automatic gain control apparatus according to an exemplary embodiment of the present invention includes an analog signal gain adjustment unit for adjusting a gain of an analog signal input at a set gain value; An analog digital converter for converting the gain-adjusted analog signal into a digital signal by the gain controller; A gain control signal generator for measuring a power of the digital signal and outputting a control signal for controlling a gain of the analog signal gain controller according to the power of the digital signal; A memory for storing a gain value and a gain adjustment point of the analog signal gain adjustment unit; And a signal gain compensator for compensating the gain of the digital signal using the gain and the gain adjustment point.

The analog signal gain adjusting unit may set the start gain of the analog signal to a maximum gain value.

Also, the analog gain controller may adjust the gain during a whole reception period of one slot of the analog signal.

In addition, the analog gain adjuster may adjust the gain during an initial part of one slot of the analog signal.

The gain control signal generator may reduce the gain of the analog signal gain controller when the power of the digital signal is higher than a predetermined reference value.

The signal gain compensator may adjust the gain of the analog signal gain adjuster to a predetermined value using a gain value and a gain adjustment point of the analog signal gain adjuster, So that the gain can be compensated.

The signal gain compensator adjusts the first section of the analog signal to a first gain value, adjusts a second section of the analog signal to a second gain value, and then adjusts a final gain value of the analog signal gain controller Adjusts a gain by compensating a first section of the digital signal by a difference between the first gain value and the third gain value, and adjusts a second section of the digital signal to a second gain Value and the third gain value to adjust the gain.

A third memory for storing the digital signal converted by the analog-to-digital converter; And a memory for storing the compensated signal in the signal gain compensation unit.

An automatic gain control method according to the present invention includes: controlling a gain value for adjusting a gain of an analog signal; Storing the gain value and the gain adjustment point while adjusting a gain of the analog signal according to the gain value; And compensating the gain of the digital signal received at the time of adjusting the gain to be a final gain value using the stored gain value and the gain adjustment time after the adjustment of the gain value is completed.

The step of adjusting the gain of the analog signal by the predetermined start gain value may set the start gain value of the analog signal to the maximum gain value.

Also, the step of controlling the gain may reduce the gain of the analog signal gain controller when the power of the digital signal is higher than a predetermined reference value.

In addition, the step of storing the gain value and the gain adjustment time while adjusting the gain of the analog signal according to the gain value may adjust the gain during the entire one slot of the analog signal.

In addition, the step of storing the gain value and the gain adjustment time while adjusting the gain of the analog signal according to the gain value may adjust the gain during an initial partial period of one slot of the analog signal.

The method may further include decreasing the final gain value by a predetermined value when the magnitude of the received signal is saturated in the analog digital converter after the gain adjustment and the gain compensation for the initial period of the slot are completed.

This technology enables automatic gain control even when the power of the received signal is not known. The technique can also operate on small signal inputs by setting the gain of the input of the analog-to-digital converter at the beginning of the receive slot to the maximum gain the system can set.

In addition, the present technology restores the gain differences due to the gain tracking process of the received signal at a digital stage so that the received signal has a constant gain during one slot, thereby preventing deterioration of the received signal due to the automatic gain control .

FIG. 1A is an exemplary diagram for explaining a TDMA communication method according to an embodiment of the present invention.
1B is an exemplary diagram according to distance and reception power in a TDMA communication scheme according to an embodiment of the present invention.
2 is a graph showing gain adjustment when the initial receiving gain is set to 50 dB.
3 is a graph showing gain adjustment when the initial receiving gain is set to -30 dB.
4 is a graph showing an example of the case where the output of the analog-to-digital converter is saturated.
5 is a configuration diagram of an automatic gain control apparatus according to an embodiment of the present invention.
6 is a flowchart showing an automatic gain control method according to an embodiment of the present invention.
7A is a diagram illustrating an example of gain adjustment of an automatic gain control apparatus according to an embodiment of the present invention.
7B is a diagram illustrating an example of gain compensation of the automatic gain control apparatus according to the embodiment of the present invention.
8A is a diagram illustrating an example of gain adjustment in consideration of a delay time for gain adjustment of an automatic gain control apparatus according to an embodiment of the present invention.
8B is a diagram illustrating an example of gain compensation in consideration of a delay time for gain adjustment of an automatic gain control apparatus according to an embodiment of the present invention.
9A is a waveform diagram showing the power of the start and end of a received signal of the automatic gain controller according to the embodiment of the present invention.
FIG. 9B is an enlarged waveform diagram of the initial signals of FIG. 9A.
10A is a waveform diagram of signals when the reception gain of the automatic gain control apparatus according to the embodiment of the present invention is set to 60 dB.
10B is a waveform diagram of a gain-compensated signal obtained by the automatic gain controller according to the embodiment of the present invention.
Fig. 11A is an enlarged view of the waveform of Fig. 10B, and is a diagram for explaining glitch.
11B is a waveform diagram when the glitch of FIG. 11A is removed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order to facilitate a person skilled in the art to easily carry out the technical idea of the present invention.

The present invention proposes a method of effectively receiving a signal by controlling gain when the power and delay time of a received signal can not be known. To this end, the present invention performs fast automatic gain control at the beginning of each reception slot to quickly follow the power of the received signal and restore the distortion of the analog-to-digital converter (ADC) It makes a constant reception signal.

Hereinafter, embodiments of the present invention will be described in detail with reference to Figs. 1 to 11B.

A TDMA (Time Division Multiple Access) communication method between general terminals is illustrated in FIG. It is assumed that the terminals A and B are the transmitting terminal and the terminal C is the receiving terminal.

The terminal A transmits a signal with a power of 20 dBm in the third slot Slot 3 of the plurality of slots Slots 0 to Slot 10 shown in FIG. 1A, and the terminal B transmits the signal with a power of 20 dBm also in the sixth slot Slot 6 do.

However, the receiving terminals receive a signal for every slot to check whether there is an actual signal, and receive a signal when there is a signal.

However, as shown in FIG. 1B, the difference in the power of the received signal may be large. When the terminal B and the terminal C are very close to each other and the terminal A and the terminal C are very distant and the communication condition is poor, the terminal C receives the terminal B signal at -30 dBm and receives the terminal A signal at -90 dBm .

When the power of the received signal is measured in such a state that the receiving power is not known and the gain is roughly adjusted using the measured power and then the gain is finely tracked continuously, the gain during tracking and the gain The received signal during tracking may be difficult to use for actual communications.

FIG. 2 shows a gain control result of a slot in which a signal of -30 dBm is received when an initial receiving gain is set to 50 dB and a signal of -70 dBm can be properly received. At this time, assuming a TDMA signal, there is a guard time between the slot and the slot. Here, it is assumed that the power of the source signal itself is constant for every slot. When the gain control signal generator 400 measures the power of the received signal and performs gain control of the analog signal gain controller 100, a predetermined delay time until the gain of the actual analog signal gain controller 100 is adjusted Occurs. That is, in order to perform the gain control, it is necessary to measure the power of the signal input to the analog-to-digital converter 200, and the time for adjusting the gain of the signal input to the analog-to- need. As shown in FIG. 2, the received signal initially has a gain of 50 dB and then converges to a gain of 0 dB. The output signal of the analog-to-digital converter 200 may be very distorted while the gain converges to an appropriate gain.

FIG. 3 shows a gain control result of a slot in which a signal of -90 dBm is received when the reception gain is set to -30 dBm. Because the initial signal is too small, it takes a long time to receive properly.

Referring to FIG. 4, a time point at which a terminal transmits a signal in the TDMA scheme is generally after a guard time has elapsed from the start of a slot. This signal is then received by the other terminal through the propagation delay between the antennas. The problem is that you generally do not know this delay time. Therefore, it is difficult for the receiving terminal to know when to start the gain control.

Assume that the gain control is performed from the point of time when the guard time has elapsed, and the propagation delay time is considerably long. Then, the reception gain control will judge that the signal is definitely small at the time of the guard time, and gradually increase the gain. Since the signal is still small even if the gain is increased, the gain finally becomes the maximum gain. At the time when the signal is actually received, the output of the analog-to-digital converter 200 can be saturated because the maximum gain value does not match the actual gain value. That is, if the size of the input signal input to the analog-to-digital converter 200 exceeds the set maximum size, the output of the analog-to-digital converter 200 is saturated. In this case, since the communication signal can not be received, the receiver must prevent the output value of the AD converter from becoming saturated.

Considering these characteristics, the present invention proposes a method of effectively receiving a signal by controlling the gain when the power and delay time of the received signal can not be known.

5 is a block diagram illustrating an automatic gain control apparatus according to an embodiment of the present invention. The automatic gain control apparatus includes an analog signal gain control unit 100, an analog digital converter 200, a memory 300, a gain control signal generating unit 400, a memory 500, A signal gain compensator 600, a memory 700, and a low-pass filter 800. [

The analog signal gain adjustment unit 100 adjusts the gain of the input analog signal using a predetermined initial gain value and outputs the gain. In addition, the analog signal gain adjusting unit 100 adjusts the gain value according to the gain control signal output from the gain control signal generating unit 400, and adjusts the gain of the input analog signal using the adjusted gain value.

The analog-to-digital converter 200 converts the analog signal output from the analog signal gain controller 100 into a digital signal.

The memory 300 stores the received signal converted into a digital signal.

The gain control signal generator 400 measures the power of the digital signal output from the analog digital converter 200 and outputs a control signal for controlling the gain of the analog signal gain controller 100 according to the measured power value .

The memory 500 receives and stores the gain value of the current analog signal gain controller 100 from the gain control signal generator 400 and stores the current time position value.

The signal gain compensation unit 600 compensates the gain of the digital signal stored in the memory 300 using the gain value and the signal position value stored in the memory 500. [ At this time, the signal gain compensator 600 may be driven after receiving the entire slot signal or when receiving only a small amount of the initial signal of the slot.

The memory 700 stores a gain compensated signal compensated by the signal gain compensation unit 600. [ Thereafter, demodulation can be continued using the gain compensated signal stored in the memory 700. [

The low-pass filter 800 removes the glitch of the gain-compensated signal compensated by the signal-gain compensator 600.

At this time, the memory 300, the gain control signal generator 400, the memory 500, the signal gain compensator 600, the memory 700, and the low-pass filter 800 are integrated into one integrated circuit (FPGA) gate array).

As described above, the present invention compensates gain of a signal that has been received secondarily in a digital terminal after primarily receiving and controlling the gain at the analog terminal.

That is, the gain of the analog signal input to the analog-digital converter 200 is adjusted at the beginning of the slot, the digital signal converted by the analog-digital converter 200 is stored in the memory 300, After the gain control is completed, information on the time point is stored in the memory 500, and then, using the received signal stored in the memory 300, the adjusted gain value stored in the memory 500, Compensates for the gain. Therefore, the gain compensated received signal has a constant gain.

As described above, the present invention compensates for the past gain of a signal that has already been received, thereby equalizing the gain of the entire received signal, thereby maintaining the demodulation performance to be ideally good. As described above, the present invention enables efficient automatic gain control even when the power of the received signal and the propagation delay time are unknown.

Hereinafter, an automatic gain control method according to an embodiment of the present invention will be described in detail with reference to FIG.

When the analog signal is received (S101), the analog signal gain control unit 100 adjusts the gain of the input analog signal using a predetermined initial gain value and outputs the adjusted analog signal (S102).

First, in the step of setting the reception gain at the beginning of the target reception period to the target gain of the reception system, the start gain is set to the target gain at the beginning of the slot, more precisely at the end of the guard time. At this time, the desired gain of the system can be set to a settable maximum gain. For example, if the terminal is designed to receive signals of -30dBm to -100dBm from 0dB to 70dB, the terminal can set the gain to 70dB at the end of the slot initial guard time.

Next, the analog-to-digital converter 200 converts the analog signal output from the analog signal gain controller 100 into a digital signal (S103). At this time, the received signal converted into the digital signal is stored in the memory 300.

Thereafter, the gain control signal generator 400 measures the power of the digital signal output from the analog-digital converter 200 and outputs a control signal for controlling the gain of the analog signal gain controller 100 according to the measured power value. (S104).

For example, when the start gain is the maximum gain, if the power of the digital signal output from the analog-digital converter 200 is greater than the predetermined power value, the gain of the analog signal gain controller 100 is lowered, The gain is maintained. Adjusting the gain in this manner will not affect the gain value even if there is no signal received during the propagation delay time after the guard time. Also, when the received signal starts to be received, the gain value will start to decrease. However, when the received signal is very small, the maximum gain value is maintained. However, in most cases the gain will be smaller because the received signal is larger than the designed minimum level.

When the start gain is set to the maximum gain, the low-noise amplifier (LN) performance of the analog receiver must be considered because if the start gain is set to the maximum gain and too high a received signal is received, Because it can distort or fail physically.

On the other hand, when the minimum gain of the system is set as the start gain, it is impossible to know whether the power of the digital signal output from the analog-digital converter 200 is small or the signal is not yet received because the received signal power is actually small. If the signal has not yet arrived at the terminal due to the propagation delay of the signal when the gain control is started after the protection time of the initial slot, the terminal determines that the signal is small. Therefore, . Therefore, setting the minimum gain to the initial gain requires a great deal of care.

One of the effective methods is to take the intermediate gain of the system as the starting gain. This method can protect the LNA in front of the signal, while the gain is less jarring than the least gain approach.

Thereafter, the gain control signal generator 400 stores the current gain value and the gain adjustment point (current time position value) of the analog signal gain controller 100 in the memory 500 (S105).

The changed gain value and the adjustment point are stored in the memory 500 while appropriately adjusting the gain with various algorithms. Here, the period for adjusting the gain by the algorithm must be determined according to the system. That is, the gain adjustment period may be the entire one slot or some time at the beginning of the slot.

If the entire slot is defined as the gain adjustment time, the signal over the entire slot must be buffered and the signal processing must be performed for all the slots, which increases the implementation burden. On the other hand, if the gain adjustment is performed only for a short period of time in the initial stage of the slot, the amount of the buffered signal is reduced and the signal processing is performed only for the signal during the gain adjustment time. Therefore, in the present invention, it is proposed to make the gain adjustment period as small as possible.

Then, the signal gain compensator 600 compensates the digital signal stored in the memory 300 to have a constant reception gain using the gain value and the signal position value stored in the memory 500 (S106).

In the step of compensating the slot signal to have a predetermined reception gain using the received signal, the stored adjustment gain value and the adjustment time, the received signal stored during the gain adjustment time is compensated by the stored adjustment gain and adjustment time together.

For example, as shown in FIG. 7A, when the initial gain is 70 dB and 100 samples are input during the gain adjustment time, the adjustment gain is changed by 60 dB after receiving the 20th sample and changed to 50 dB after receiving the 90th sample, 50 dB is assumed. Then, as shown in FIG. 7B, the gains of -20 dB for samples # 1 to # 20, -10 dB for samples # 21 to # 90, and 0 dB for samples # 91 to # 100 are compensated in the digital domain. Then, the gain of the entire received signal is all 50 dB. 7A and 7B are cases in which it is assumed that there is no delay time for changing the adjustment gain.

However, the adjustment gain varies depending on the system, and the delay time is different from each other. Therefore, for correct gain compensation, the gain should be compensated by considering this delay time. In the previous case, it is assumed that the gain change delay time takes three sample times.

As shown in FIG. 8A, the gain adjustment is started after three sample times of the received signal. As shown in FIG. 8B, the gains of -20 dB for samples 1 to 23, -10 dB for samples # 24 to # 93, and 0 dB for samples # 94 to # 100 must be compensated in the digital domain. The signal compensated with the constant gain does not cause deterioration in performance in the demodulation signal processing.

For reference, the present invention can be applied to various systems, but among them, it is very effective for a TDMA system. This is because in the case of TDMA signals, filters are used to prevent spurious in the transmit side spectrum and to limit the transmit signal to a given frequency band. Due to the use of the filter, the start and end of the signal become increasingly larger or smaller as shown in FIG. 9A. FIG. 9B is an enlarged view of signal initial values in FIG. 9A. The initial values of the signal are a form of increasing power. Therefore, when the signal starts to saturate after setting the start gain to the maximum gain, a method of gradually reducing the gain can be applied very effectively.

10A shows a received signal waveform when the antenna input signal is set to -30 dBm power and the start gain is set to 60 dB in a system where the reception gain is set from 0 dB to 60 dB for signals of -30 dBm to -90 dBm. The initial waveform of the received signal is shown as the gain is varied until the proper gain of 0 dB is reached. Referring to FIG. 10A, in the gain change area, the initial received signal has a gain value larger than a normal gain until a proper gain is set. Here, the power of the original signal source is as shown in FIG.

FIG. 10B is an initial waveform of a signal in which the gain is compensated by applying the present invention. The waveform of this signal is almost the same as the waveform of Fig. 9B. Thus, it can be seen that the present invention can perform signal reception without distortion without using a preamble for AGC, using gain compensation.

In real hardware implementation, knowing the exact latency is not an easy task. Although it takes into account the delay time required to change the tuning gain, it may be difficult for the system to fully implement the hardware. In that case, a glitch is generated. For example, if the gain adjustment occurs in the nth sample and it takes 3.5 sample times to change the actual adjustment gain, the gain of the (n + 4) th sample is large at the input of the actual analog to digital converter 200, Glitch is generated because it is compensated with a small gain. An example of such a glitch is shown in FIG. These glitches can be removed with a low-pass filter. At this time, the bandwidth of the low-pass filter should be larger than the signal bandwidth. FIG. 11B is an illustration showing the removal of the glitch of FIG. 11A. FIG.

Finally, there is one further consideration for the efficient use of the present invention. One of the most effective uses of the present invention is to perform gain control and gain compensation after reception at the beginning of the signal and then continue to use the gain of the input of the analog-to-digital converter to the end of the slot as the finally set gain value at the beginning. This type of implementation is easy to implement with hardware and is not a problem in most cases.

However, there is a problem in the case where the gain of the wireless channel fluctuates so much that the gain of the channel is very small at the initial stage of the slot and the channel gain increases toward the rear end of the slot. In such a channel situation, even if an appropriate gain value is found and set at the initial stage of the slot, the output of the analog / digital converter 200 is saturated because the channel gain becomes larger thereafter. Of course, if gain control and gain compensation are performed throughout a slot, there will be no problem, but this is a very complicated and difficult implementation.

Therefore, the present invention proposes a method for preventing a signal from being saturated after the beginning of a slot when the final gain is determined at the beginning of the slot to compensate for the gain of the initial received signal and thereafter continues to use the final gain. It is to reduce the final determined gain value by a certain amount when the signal is saturated. In this way, it is possible to prevent most of the received signal from being saturated. It should be noted that, unlike compensating the gain of the received signal after gain control at the beginning of the slot, there is no gain compensation after the final gain after signal gain compensation is reduced. Because even if the gain is multiplied by a gain greater than one to compensate for the saturated signal, the signal is also saturated.

According to the present invention, since the start gain of the AD converter input terminal at the start of the reception slot can be set to the maximum gain that can be set by the system, it is possible to operate also for a small signal input. In addition, since the received signal restores the gain differences due to the gain tracking process at a digital stage, the received signal has a constant gain during one slot, and as a result, the quality deterioration of the received signal due to the automatic gain control can be prevented have.

The present invention can be very usefully used in a system where rarely communication is performed between terminals without a base station that always transmits signals, such as D2D communication and maritime communication.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It should be regarded as belonging to the claims.

Claims (16)

An analog signal gain adjustment unit for adjusting a gain of an analog signal input as a set gain value;
An analog digital converter for converting the gain-adjusted analog signal into a digital signal by the gain controller;
A gain control signal generator for measuring a power of the digital signal and outputting a control signal for controlling a gain of the analog signal gain controller according to the power of the digital signal;
A memory for storing a gain value and a gain adjustment point of the analog signal gain adjustment unit; And
A signal gain compensator for compensating a gain of the digital signal using the gain and the gain adjustment point;
And an automatic gain control device. The method according to claim 1,
Wherein the analog signal gain adjuster comprises:
And sets the start gain of the analog signal to a maximum gain value. The method according to claim 1,
The analog gain adjuster includes:
And adjusts the gain during a whole reception period of one slot of the analog signal. The method according to claim 1,
The analog gain adjuster includes:
And adjusts the gain during an initial part of one slot of the analog signal. The method according to claim 1,
Wherein the gain control signal generator comprises:
And decreases the gain of the analog signal gain adjusting unit when the power value of the digital signal is higher than a predetermined reference value. The method according to claim 1,
Wherein the signal gain compensator comprises:
After the gain adjustment of the analog signal gain adjustment unit is completed,
And compensates the digital signal received during the gain adjustment period of the signal gain adjustment unit to a predetermined gain value by using the gain value and the gain adjustment point of the analog signal gain adjustment unit. The method of claim 6,
Wherein the signal gain compensator comprises:
Adjusting a first section of the analog signal to a first gain value and adjusting a second section of the analog signal to a second gain value and then when the final gain value of the analog signal gain adjustment section converges to a third gain value , Adjusting a gain by compensating a first section of the digital signal by a difference between the first gain value and the third gain value and adjusting a second section of the digital signal by using the second gain value and the third gain value And the gain is adjusted by compensating for the difference. The method according to claim 1,
A third memory for storing the converted digital signal from the analog digital converter; And
A memory for storing a signal compensated by the signal gain compensator,
Further comprising: a gain control unit for controlling the gain of the automatic gain control unit. The method according to claim 1,
A low-pass filter for removing glitches of the compensated signal in the signal gain compensator;
Further comprising: a gain control unit for controlling the gain of the automatic gain control unit. The method according to claim 1,
Wherein the gain control signal generator comprises:
Wherein the automatic gain control unit reduces the gain of the analog signal gain control unit when the magnitude of the signal received after the gain adjustment and gain compensation for the initial period of the slot is saturated by the analog digital converter . Adjusting a gain of the analog signal inputted by the predetermined start gain value;
Converting the gain-adjusted analog signal into a digital signal;
Measuring a power of the digital signal and controlling a gain value for gain adjustment of the analog signal according to the power of the digital signal;
Storing the gain value and the gain adjustment point while adjusting a gain of the analog signal according to the gain value;
Compensating the gain of the digital signal received at the time of adjusting the gain to be a final gain value using the stored gain value and the gain adjustment time after the adjustment of the gain value is completed;
And an automatic gain control method. The method of claim 11,
Wherein the step of adjusting the gain of the analog signal by the predetermined start gain value comprises:
And setting a starting gain value of the analog signal to a maximum gain value. The method of claim 11,
Controlling the gain value;
And decreasing a gain value of the analog signal gain adjusting unit when the power value of the digital signal is higher than a predetermined reference value. The method of claim 11,
Wherein the step of storing the gain value and the gain adjustment point while adjusting the gain of the analog signal according to the gain value comprises:
And adjusts the gain during the entire one slot of the analog signal. The method of claim 11,
Wherein the step of storing the gain value and the gain adjustment point while adjusting the gain of the analog signal according to the gain value comprises:
And adjusts the gain during an initial partial period of one slot of the analog signal. 16. The method of claim 15,
If the magnitude of the signal received after saturation of the gain adjustment and gain compensation for the initial period of the slot is saturated in the analog digital converter, reducing the final gain value by a predetermined value
Further comprising the steps of:

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