KR20090003793A - Auto gain controller and method of auto gain control - Google Patents

Auto gain controller and method of auto gain control Download PDF

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Publication number
KR20090003793A
KR20090003793A KR1020070066746A KR20070066746A KR20090003793A KR 20090003793 A KR20090003793 A KR 20090003793A KR 1020070066746 A KR1020070066746 A KR 1020070066746A KR 20070066746 A KR20070066746 A KR 20070066746A KR 20090003793 A KR20090003793 A KR 20090003793A
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KR
South Korea
Prior art keywords
signal
level
gain control
comparator
amplifier
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Application number
KR1020070066746A
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Korean (ko)
Inventor
김남흥
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삼성전기주식회사
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Priority to KR1020070066746A priority Critical patent/KR20090003793A/en
Publication of KR20090003793A publication Critical patent/KR20090003793A/en

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers without distortion of the input signal
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3052—Automatic control in amplifiers having semiconductor devices in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers without distortion of the input signal
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3052—Automatic control in amplifiers having semiconductor devices in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver
    • H03G3/3078—Circuits generating control signals for digitally modulated signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40—Circuits
    • H04B1/403—Circuits using the same oscillator for generating both the transmitter frequency and the receiver local oscillator frequency
    • H04B1/406—Circuits using the same oscillator for generating both the transmitter frequency and the receiver local oscillator frequency with more than one transmission mode, e.g. analog and digital modes

Abstract

The present invention provides an amplifying unit for receiving and amplifying an RF signal in which the operation mode and the idle mode are repeated, a gain controlled according to a gain control signal, a level detector for detecting an output level of the amplifying unit, and the detected output level. A gain control signal generator for transmitting the gain control signal to the amplifier according to the output of the comparator, and a gain control signal in each operation mode of the RF signal. And a memory device for storing, wherein the memory device provides a gain control signal in the stored previous operation mode to the amplifier when the operation mode of the RF signal is started. A control method can be provided.

Description

AUTO GAIN CONTROLLER AND METHOD OF AUTO GAIN CONTROL}

The present invention relates to an automatic gain controller (AGC), and more particularly, to an automatic gain controller capable of shortening an automatic gain control loop time.

In a wireless communication system, the baseband signal at the receiver is converted from an analog format to a digital format so that useful information in the signal can be recovered by a series of digital processes. Typically an analog-to-digital converter (ADC) is used to achieve this conversion. In general, the more bits an ADC has, the more the ADC can support an input signal with a wider operating range. However, this makes the ADC more expensive. Given the number of output bits, if the input signal power is too large, the output of the ADC will saturate. On the other hand, if the power of the input signal is too small, the output of the ADC is seriously quantized.

A common approach to solve this problem is to apply a dynamically adjustable gain amplifier in front of the ADC so that the input signal of the ADC stays within the desired limits. Typically, the adjustable gain is controlled using an automatic gain control (AGC) circuit.

In general, the automatic gain control circuit forms a feedback loop that can adjust the gain according to the magnitude of the input signal, thereby enabling a constant output. The gain control here is possible by adjusting the bias level for the input signal.

AGC loop time in time division receiving system is one of the factors to measure how fast the reception system can be stabilized when the strength of received signal is changed. The longer the loop time, the longer it takes for the receiving system to stabilize, and the input signal cannot be output as a constant sized output signal.

According to the conventional method, when the time division receiving system changes from the active mode to the sleep mode, all the circuit blocks go to the sleep mode, so that the AGC is executed from the beginning when the operation mode is started again. Therefore, the AGC loop time is long.

In order to solve the above problems, an object of the present invention is to provide an automatic gain controller and an automatic gain control method capable of reducing the automatic gain control loop time in a time division receiving system.

According to an aspect of the present invention, an amplifying unit receives and amplifies an RF signal in which the operation mode and the idle mode are repeated, and a gain is controlled according to a gain control signal, a level detector for detecting an output level of the amplifying unit, and the detected signal. A comparator for comparing an output level with a predetermined reference voltage level, a gain control signal generator for transmitting the gain control signal to the amplifier according to the output of the comparator, and gain control in each operation mode of the RF signal And a memory device for storing a signal, wherein the memory device provides a gain control signal in the stored previous operation mode to the amplifier when the operation mode of the RF signal is started. Can provide.

The gain control signal may be a bias level according to the signal voltage.

The amplifier includes a digital control amplifier (DCA) for controlling a digital gain with respect to an input RF signal, and a voltage for adjusting an output voltage by receiving an output of the digital control amplifier and an output signal of the level detector. It may include a control amplifier (VCA: Voltage Control Amplifer).

The automatic gain controller may further include a switch formed between the level detector and the voltage control amplifier (VCA) and switched on or off in accordance with an operation mode or an idle mode of the RF signal.

The automatic gain controller may further include a loop filter connected between the level detector and the voltage control amplifier (VCA) to stabilize the detected output level.

The comparator is a first comparator that operates when the output level of the level detector is equal to or greater than a predetermined threshold voltage relative to the reference voltage level, and a first comparator that operates when the output level of the level detector is not equal to the reference voltage level. A second comparator, and a third comparator that operates when the output level of the level detector is less than or equal to a predetermined threshold voltage with respect to the reference voltage level.

The gain control signal generator is connected to the first comparator and the third comparator, and a pulse generator for generating a pulse when the first or third comparator is operated, is connected to the pulse generator and the second comparator, The pulse generator may include an up-down counter that up / down the bias level when a pulse is generated and the second comparator is operated.

According to another aspect of the present invention, there is provided an amplifying unit for amplifying an operation mode of a gain control signal and a time-divided RF signal, detecting an output level of the amplified signal, Comparing the level with a predetermined reference voltage level, generating the gain control signal according to the comparison result, storing the gain control signal (bias level) in the operation mode of the RF signal, and The method may further include feeding back the stored gain control signal (bias level) to the amplifier.

The gain control signal may be a bias level according to the signal voltage.

The storing of the gain control signal may be performed at the end of one operation mode of the RF signal, and feeding back the stored gain control signal to the amplifier may include starting the next operation mode of the one operation mode. Can proceed at a time point.

According to the present invention, an automatic gain controller (AGC) and an automatic gain control method capable of reducing the automatic gain control loop time for a time-division RF input signal can be obtained.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 is a configuration diagram of an automatic gain controller (AGC) according to an embodiment of the present invention.

Referring to FIG. 1, the automatic gain controller 100 according to the present embodiment includes an amplifier 10, a level detector 20, a comparator 30, a gain control signal generator 40, and a memory device 50. ) May be included.

The amplifier 10 may receive and amplify an RF signal in which the operation mode and the idle mode are repeated. In this case, a gain value applied to the RF signal by the amplifier may be controlled by the gain control signal generator 40. The automatic gain controller according to the present embodiment can lower the gain of the amplifier 10 when the input signal is large and increase the gain of the amplifier 10 when the input signal is small.

The level detector 20 may detect the output level of the amplifier 10. The output level detected by the level detector 20 may be transmitted to the comparator 30.

The comparator 30 may compare the detected output level with a predetermined reference voltage level. In the comparator 30, when the output level is different from the reference voltage level, the comparator 30 may transmit a signal to the gain control signal generator 40 to adjust the output level.

The gain control signal generator 40 may transmit a signal for shifting a bias level with respect to an input signal according to the output of the comparator 30 to the amplifier. That is, when the output level detected by the comparator 30 is different from the preset reference voltage level, the bias level with respect to the input signal may be adjusted to change the output level closer to the reference voltage level.

The memory device 50 stores the bias level generated by the gain control source generation unit in one operation mode of the RF signal, and stores the bias level stored in the memory when the next operation mode of the RF signal starts. It may be provided to the amplifier. The memory device may be connected to the input signal in order for the memory device to function according to an operation mode and an idle mode of the input signal. As such, the automatic gain control loop time can be reduced by storing the bias level in one operation mode in the memory device and making it available in the next operation mode.

2 is a configuration diagram of an automatic gain controller AGC according to another embodiment of the present invention.

Referring to FIG. 2, the automatic gain controller 200 according to the present embodiment includes an amplifier 10, a level detector 20, a comparator 30, a gain control signal generator 40, and a memory device 50. ) May be included.

The amplifier 10 may receive a time-divided RF signal as an input and output a predetermined output signal. The amplifier 10 may include a digital control amplifier 11 and a voltage control amplifier 12.

The digital control amplifier (DCA) 11 may multiply and output a predetermined gain with respect to an input time division RF signal. The gain may be changed by a gain control signal applied to the digital control amplifier 11.

The output of the digital control amplifier 11 may be input to a voltage control amplifier (VCA) 12. The digital control amplifier 11 performs digital processing on the input signal, while the voltage control amplifier 12 may perform analog processing on the input signal. As such, by connecting the digital control amplifier 11 and the voltage control amplifier 12 in series, the linearity of the output signal with respect to the input signal can be improved.

The level detector 20 may detect the level of the signal output from the amplifier 10.

The signal output from the level detector 20 may be fed back to the voltage control amplifier 12. The feedback of the detection signal to the voltage control amplifier 12 may enable analog control of the output of the automatic gain controller.

In this case, a loop filter 61 may be further included between the level detector 20 and the voltage control amplifier 12. The loop filter 61 may further stabilize the detection signal for controlling the voltage control amplifier 12.

A switch 62 may be further included between the level detector 20 and the voltage control amplifier 12. The switch 62 may be in an ON state in an operation mode of the RF signal and in an OFF state in an idle mode. As such, by turning off the switch in the idle mode of the RF signal, the voltage control amplifier 12 can be maintained in a high impedance state even in the idle mode of the RF signal.

The comparator 30 may compare the level of the signal output from the level detector 20 with a predetermined reference voltage level. The comparator 30 may include a first comparator 31, a second comparator 32, and a third comparator 33.

In the second comparator 32, an output signal of the level detector 20 may be input to a plus terminal, and a predetermined reference voltage V ref level may be input to a negative terminal. The output of the second comparator 32 may be connected to the counter 42.

If the detection signal input to the second comparator 32 is different from the reference voltage V ref level, the second comparator 32 sends an operation signal to the counter 42, and the counter 42 Prepare for up / down. On the contrary, when the input detection signal and the reference voltage (V ref ) level are the same, the second comparator 32 may not operate and the counter 42 may not operate at all.

The first comparator 31 and the third comparator 33 may distinguish whether the output signal of the level detector 20 is greater or smaller than the preset voltage level. That is, to the negative input terminal of the first comparator 31 and the third comparator 33, a value (V ref + ΔV, V ref -ΔV) to which a predetermined threshold level is added or subtracted from the reference voltage level is respectively input. Can be. The predetermined threshold level value may be large enough to turn on the counter 42.

Outputs of the first comparator 31 and the third comparator 33 may be connected to an OR gate 34 and may be connected to a pulse generator 41.

That is, when the detection signal level input to the first comparator 31 is greater than or equal to the threshold voltage level, the first comparator 31 may operate to generate a pulse in the pulse generator 41. .

In addition, when the detection signal level input to the third comparator 33 is less than or equal to the threshold level than the reference voltage level, the third comparator 33 is operated to generate a pulse in the pulse generator 41. Can be.

When the first comparator 31 is operated in this manner, the pulse generator 41 may generate a pulse and may count up the bias level at the counter 42. In addition, when the third comparator 33 is operated, a pulse may be generated by the pulse generator 41, and the counter 42 may be down counted with respect to the bias level.

The memory device 50 may store a bias level in one operation mode of the RF signal.

When the operation mode of the time-divided RF signal ends and the idle mode starts, the operation of the automatic gain controller AGC is stopped, but the bias level for the input signal in the operation mode may be stored in the memory.

Therefore, when the idle mode of the RF signal ends and the operation mode starts again, the loop of the automatic gain controller AGC may be started from the stored bias level. As such, storing the bias level in one mode of operation and using it at the beginning of the next mode of operation is more automatic than in the prior art, where a new loop of automatic gain controller is started each time the mode of operation is started without the stored bias level. The gain control loop time can be reduced.

3 is a graph for adjusting the bias level in the automatic gain controller according to the embodiment of the present invention. Each step of the loop in the automatic gain controller may move one step in the graph. That is, the bias level can be shifted.

According to the related art, the reference voltage level preset in FIG. 3 is V ref , and the output level of the signal input in the first operation mode is V 1 , and the signal input in the second operation mode that is continuous with the first operation mode. If the output level is V 2 , in the first operation mode, the automatic gain controller should move the bias level by (a), and then move the bias level by (b) in the second operation mode again after the idle mode. . In this manner, each time the operation mode signal is input again after the idle mode, the automatic gain control loop for shifting the bias level is started from the beginning, thereby increasing the loop time.

However, in the case where the bias level M is stored in the memory device in the first operation mode and the bias level is applied in the second operation mode as in the present embodiment, the output level of the second operation mode is V 3 . Will be. Therefore, a bias level as much as (c) may be achieved in accordance with the reference voltage level V ref . Thus, the time for the automatic gain control loop can be reduced as compared with the prior art.

4 is a block diagram showing a method of automatic gain control according to an embodiment of the present invention.

Referring to FIG. 4, the automatic gain control method according to the present embodiment includes amplifying an input RF signal (401), detecting an output level of the amplified signal (402), and detecting the detected output level. Comparing a predetermined reference voltage level (403), generating a gain control signal for shifting a bias level with respect to an input signal according to the comparison result (405), and storing (406) the bias level; It may include.

The RF signal may be a time-divided signal and a signal in which the operation mode and the idle mode are repeated. In the amplifying step, a predetermined gain value may be applied to the input signal. The gain value may be determined by comparing the output level of the amplifier with a preset reference voltage level.

In the step 403 of comparing the output level with a predetermined reference voltage level, if the output level is equal to the reference voltage level, the automatic gain control (AGC) loop is stopped (404).

When the output level is greater than the reference voltage level, the gain control signal generation step 405 may generate a gain control signal to move the bias level in a direction lower than the output level.

If the output level is less than the reference voltage level, the gain control signal generation step 405 may generate a gain control signal to move the bias level in a direction higher than the output level.

The shifted bias level value may be stored 406 in the memory device.

The bias level value stored in the memory may be used in the amplifying step 401.

The storing of the bias level in the memory is performed at the end of one operation mode of the RF signal, and in the providing of the bias level stored in the memory to the amplifier, the next operation mode of the one operation mode is It may proceed at the beginning.

As such, the present invention is not limited by the above-described embodiment and the accompanying drawings. That is, the shape of the amplifier and the comparator may be variously implemented. It is intended that the scope of the invention be defined by the appended claims, and that various forms of substitution, modification, and alteration are possible without departing from the spirit of the invention as set forth in the claims. Will be self-explanatory.

1 is a configuration circuit diagram of an automatic gain controller according to an embodiment of the present invention.

2 is a configuration circuit diagram of an automatic gain controller according to another embodiment of the present invention.

3 shows a graph for adjusting a bias level in an automatic gain controller according to an embodiment of the present invention.

4 is a block diagram of an automatic gain control method according to an embodiment of the present invention.

<Code Description of Main Parts of Drawing>

10: amplification unit 20: level detector

30: comparator 40: gain control signal generator

50: memory device

Claims (10)

An amplifier for receiving and amplifying an RF signal in which the operation mode and the idle mode are repeated, and controlling gain according to a gain control signal; A level detector for detecting an output level of the amplifier; A comparator for comparing the detected output level with a preset reference voltage level; A gain control signal generator for transmitting the gain control signal to the amplifier according to the output of the comparator; And A memory device for storing a gain control signal in each operation mode of the RF signal Including; And the memory device provides a gain control signal in the stored previous operation mode to the amplifier when one operation mode of the RF signal is started. The method of claim 1, The gain control signal is, Automatic gain controller, characterized in that the bias level according to the signal voltage. The method of claim 2, The amplification unit, A digital control amplifier (DCA) for controlling the digital gain for the input RF signal; And A voltage control amplifier (VCA) for controlling the output voltage by receiving the output of the digital control amplifier and the output signal of the level detector; Automatic gain controller comprising a. The method of claim 3, Is formed between the level detector and the voltage control amplifier (VCA), Switch that is turned on or off according to the operation mode or the idle mode of the RF signal Automatic gain controller, characterized in that it further comprises. The method of claim 3, A loop filter connected between the level detector and the voltage control amplifier (VCA) to stabilize the detected output level Automatic gain controller, characterized in that it further comprises. The method of claim 2, The comparator, A first comparator operating when the output level of the level detector is equal to or greater than a predetermined threshold voltage relative to the reference voltage level; A second comparator operating when the output level of the level detector is not equal to the reference voltage level; And A third comparator operating when the output level of the level detector is below a predetermined threshold voltage with respect to the reference voltage level; Automatic gain controller comprising a. The method of claim 6, The gain control signal generator, A pulse generator connected to the first comparator and the third comparator to generate a pulse when the first or third comparator is operated; An up-down counter coupled to the pulse generator and the second comparator, the up and down counters up and down a bias level when a pulse is generated at the pulse generator and the second comparator is operated; Automatic gain controller comprising a. Amplifying and receiving an operation mode of a gain control signal and a time division RF signal from an amplifier; Detecting an output level of the amplified signal; Comparing the detected output level with a predetermined reference voltage level; Generating the gain control signal according to the comparison result; Storing a gain control signal (bias level) in an operating mode of the RF signal; And Feeding back the stored gain control signal (bias level) to the amplifier. Automatic gain control method comprising a. The method of claim 8, The gain control signal is, Automatic gain control method characterized in that the bias level according to the signal voltage. The method of claim 8, The storing of the gain control signal may include: Proceeds at the end of one operation mode of the RF signal, The step of feeding back the stored gain control signal to the amplifier, The automatic gain control method characterized in that the progress of the next operation mode of the one operation mode starts.
KR1020070066746A 2007-07-03 2007-07-03 Auto gain controller and method of auto gain control KR20090003793A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101041853B1 (en) * 2010-10-28 2011-06-15 엘아이지넥스원 주식회사 Transceiver

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101041853B1 (en) * 2010-10-28 2011-06-15 엘아이지넥스원 주식회사 Transceiver

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