KR101008614B1 - Auto gain controller in receiver - Google Patents

Abstract

The present invention relates to automatic gain control in a receiver, and in particular, to combine the analog and digital automatic gain control device and the digital automatic gain control device in a cascade to increase the input dynamic range and to make fine adjustments. One automatic gain control device relates.

Automatic Gain Control, AGC

Description

Automatic gain controller in receiver

1 illustrates an automatic gain control apparatus in a receiver according to the prior art.

2 is a diagram illustrating an automatic gain control apparatus in a receiver according to a first embodiment of the present invention.

3 is a diagram illustrating an automatic gain control apparatus in a receiver according to a second embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

100: A / D conversion unit 120,130: I, Q output means

140150: LPF 160170: Format Converter

180,190: Squarer 200,210,220,250: Adder

The present invention relates to an automatic gain control in a receiver, and more particularly, in a receiver that combines an analog and digital automatic gain control device and a digital automatic gain control device with a cascad to increase the input dynamic range and make fine adjustment. Relates to an automatic gain control device.                         

In general, the reception path of a CDMA base station, which is a digital reception method, includes an upconverter for up-adjusting an amplifier, a transmission antenna, a frequency signal, and an FPGA (Field) for forming an I / Q signal transmission logic. programmable gate array) and a baseband signal processor for processing the baseband signal.

Here, the baseband signal processing unit converts the baseband signal I (inphase) / Q (quardrature) signal to an IF signal, and the I signal and Q signal level are various, such as temperature and characteristic tolerances of the components. Unbalance is caused by factors, and unbalance of two signal levels acts as a detrimental effect on RF reception characteristics.

Accordingly, in the digital receiver, an imbalance between the I signal and the Q signal level needs to be fed back to the automatic gain control (AGC) device with respect to the received Rx IF input signal, thereby voltage-controlled amplification to a constant value.

Hereinafter, an automatic gain control apparatus in a receiver according to the prior art will be described with reference to the accompanying drawings.

1 is a view for explaining an automatic gain control apparatus in a receiver according to the prior art.

The automatic gain control apparatus according to the prior art includes a variable gain amplifier (hereinafter, referred to as an AMP) 10 for variable-gain amplifying the received analog IF (intermediate frequency) signal IF_A. The analog-to-digital converter (hereinafter referred to as ADC) 11 for converting the variable-gain amplified analog intermediate frequency signal into a digital intermediate frequency signal, and the digital intermediate frequency signal converted by the ADC 11 Multipliers (12, 13) for down-conversion and IQ demultiplexing to output digital I and Q signals, and down-converted and IQ demultiplexed I and Q in multipliers (12, 13). The first and second LPFs 14 and 15 for passing only the baseband signal in the digital signal of the first and the first and second LPFs 14 and 15 for adjusting the output bits of the I and Q signals from the first and second LPFs 14 and 15, respectively. Output of the second format converters 16 and 17 and the first and second format converters 16 and 17 First and second squarers (18, 19) to square respectively, and the adder (20) for outputting the power value (P) by digitally summing the output signals from the first and second squarers (18, 19) And a subtractor 21 for summing the power value P output from the adder 20 and a specific value to obtain a difference in power, and an output bit for adjusting the output bit of the digital output signal from the subtractor 21. A third format converter 22, a digital-to-analog converter (hereinafter referred to as a DAC) 23 for converting the digital output signal of the third format converter 22 into an analog signal, and a DAC ( 23) is composed of an integrator 24 for integrating and outputting an analog signal, and the AMP 10 receiving the integrated analog signal from the integrator 24 adjusts the gain of the received analog intermediate frequency signal IF_A. Done.

In the automatic gain control apparatus of the receiver according to the related art, first, an analog IF (intermediate frequency) signal is amplified by the AMP 10 and then converted into a digital intermediate frequency signal through the ADC 11. .

It is down-converted and I-Q demultiplexed via multipliers 12 and 13 and then through the first and second LPFs 14 and 15 to become digital baseband signals.                         

This signal can be obtained by the adder 20 via the first and second multipliers 18 and 19 to obtain the power of this signal. Another adder 21 calculates a difference from this power from a specific value and converts it to an analog signal through a digital-to-analog converter 23 (hereinafter referred to as DAC). This analog signal is input through the integrator 24 and then input to a control port of the AMP 10 to adjust the gain of the analog intermediate frequency signal.

In the conventional art, the ADC 11 can be used to widen the dynamic range of the analog intermediate frequency signal. In the related art, an automatic gain control (AGC) device forms a negative feedback loop to form an analog. Output a digital baseband signal having a constant power for the intermediate frequency signal.

This automatic gain control (AGC) is called a mixed AGC because it is a combination of analog and digital. However, the mixed AGC requires analog tuning as a part of an unstable element called DAC 103 that converts a digital signal into an analog signal. However, if this analog tuning is wrong, the power of the digital baseband output signal will be out of the target value.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and the input dynamic range and fine adjustment are possible by serially combining analog automatic gain control and digital automatic gain control in an automatic gain control circuit among CDMA base station receivers. It is to provide an automatic gain control device in a receiver.

Other objects, features and advantages of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

According to one aspect of the present invention, an analog / digital converter for converting a received analog input signal into a digital frequency signal, I, Q output means for outputting the digital frequency signal as a digital I signal and a Q signal, respectively, A first and second squarers that square the digital signals of I and Q at the I and Q output means, and digitally sum the output signals at the first and second squarers and calculate a difference in power between a specific value. Means, a digital integrator for integrating the digital output signal from said computing means, and a multiplier for multiplying the output value from said digital integrator with said digital frequency signal.

Here, the digital integrator is composed of an adder and a memory.

Preferably, the digital frequency signal further comprises a mixed automatic gain control unit for adjusting the gain of the analog input signal through a signal through a negative feedback loop (negative feedback loop), the mixed automatic gain control unit, A variable gain amplifier for variable gain amplifying an analog intermediate frequency signal, a square unit for squaring the digital frequency signal, an operation unit for obtaining a difference between the output of the square unit and the power of a specific value, and an output signal of the operation unit A digital / analog converter for converting the signal, and an integrated part for integrating and outputting an analog signal from the digital / analog converter, and a variable gain for varying and amplifying the gain of the received analog input signal according to the output of the integral part. It further includes an amplifier.

Preferably, the mixed automatic gain control unit comprises: a variable gain amplifier for variable gain amplifying the received analog intermediate frequency signal, an absolute value extracting unit for obtaining an absolute value of the digital frequency signal, an output and specification of the absolute value extracting unit; A computing unit for obtaining a difference in power of a value, a digital / analog converter for converting the output signal of the computing unit into an analog signal, and an integrated unit for integrating and outputting the analog signal from the digital / analog converter.

Preferably, an adder is further included between the digital integrator and the multiplier so that the output value of the digital integrator is always positive.

According to another aspect of the present invention, an analog / digital converter for converting and outputting a received analog input signal into a digital frequency signal and a mixed automatic for feeding back the digital frequency signal to adjust the amplification gain of the input signal. And a digital automatic gain control means cascaded with the gain control part and cascaded with the mixed automatic gain control part to adjust the gain for the digital frequency signal.

Hereinafter, an automatic gain control apparatus in a receiver according to the present invention will be described with reference to the accompanying drawings.

2 is a view for explaining an automatic gain control apparatus according to a first embodiment of the present invention.

The automatic gain control device according to the first embodiment of the present invention includes an analog-to-digital converter (hereinafter, referred to as an ADC) 100 for converting a received analog intermediate frequency signal into a digital intermediate frequency signal, and an ADC. I, Q output means (120,130) and I, Q output means for down-conversion and IQ demultiplexing the digital intermediate frequency signal converted at (100) to output digital I and Q signals. First and second LPFs 140 and 150 which pass only the baseband signal in the downconverted and IQ demultiplexed I and Q digital signals at 120 and 130 and I from the first and second LPFs 140 and 150. The first and second format converters 160 and 170 for adjusting the output bits of the Q signal, the first and second squarers 180 and 190 for squaring the outputs of the first and second format converters 160 and 170, respectively, The power values P are output by digitally summing output signals at the first and second squarers 180 and 190. The work adder 200 and the other adder 210 which calculates the difference in power by summing a specific value and the power value P output from the adder 200 (here, the work adder 200 and the other adder 210 ) May be constituted by one computing means as needed), a digital integrator comprising an adder 220 and a memory 230 for integrating the digital output signal from the other adder 210, and desired automatic gain control. The adder 250 adds a value and an output value from the digital integrator, and a multiplier 110 multiplying the output value in the adder 250 and the digital intermediate frequency signal converted in the ADC 100, and in particular, the output signal of the adder 250. Can be configured to always be positive.

In the first exemplary embodiment of the present invention, the digital output signal from the adder 220 and the memory of the adder 210, which calculates the difference in power by summing the power value P output from the adder 200 and a specific value, are added to the adder 220 and the memory. By digitally integrating the digital integrator consisting of 230, a very fine adjustment is possible by digitally controlling analog instability.

3 is a diagram for describing an automatic gain control apparatus in a receiver according to a second embodiment of the present invention.

The automatic gain control device according to the second embodiment of the present invention is a cascade automatic gain control device in which a part of the prior art shown in FIG. 1 is mixed with the automatic gain control device according to the first embodiment of the present invention shown in FIG. 2. to be. In other words, the digital frequency signal further includes a mixed automatic gain control unit 400 that adjusts the gain of the analog input signal through a signal through a negative feedback loop.

The automatic gain control device according to the second embodiment of the present invention is a variable gain amplifier (hereinafter, referred to as an AMP) that variably amplifies a received analog IF (intermediate frequency) signal IF_A. 300, an analog-to-digital converter (hereinafter, referred to as an ADC) 310 for converting a variable-gain amplified analog intermediate frequency signal into a digital intermediate frequency signal, and a digital signal converted by the ADC 310; A square unit 320 for squaring the intermediate frequency signal, a calculator 330 for summing a specific value with the power value P output from the square unit 320, and a calculator 330. A third format converter 340 for adjusting an output bit of the digital output signal, and an analog-to-analog converter (hereinafter, referred to as a digital-to-analog converter) for converting the digital output signal of the third format converter 340 into an analog signal. DAC 350 and DAC 350 The mixed AGC 400, which is composed of an integrator 360 for integrating and outputting analog signals, receives an integrated analog signal from the integrator 360. And outputs by adjusting the gain of the analog intermediate frequency signal IF_A) and the digital intermediate frequency signal converted by the ADC 310 by down-conversion and IQ demultiplexing. I, Q output means (120,130) for outputting and Q signal, and the first and second to pass only the baseband signal in the digital signal of I and Q down-converted and IQ demultiplexed in the I, Q output means (120,130) LPFs 140 and 150, first and second format converters 160 and 170 for adjusting output bits of I and Q signals from the first and second LPFs 140 and 150, and first and second format converters. First and second squarers 180 and 190 that square outputs 160 and 170, respectively, and the first and second squarers An adder 200 for digitally summing output signals at 180 and 190 to output a power value P, and another adder for summing power values P and a specific value output from the adder 200 to obtain a difference in power. (Can also be a subtractor) 210 (where the adders 200 and 210 can be configured as one computing means as required), and an adder 220 integrating the digital output signal from the other adder 210; A digital integrator composed of a memory 230, an adder 250 that adds a desired automatic gain control value and an output value of the digital integrator, and a multiplier that multiplies the output value in the adder 250 and the digital intermediate frequency signal converted by the ADC 100. It consists of a digital AGC unit 500 composed of (110).

Here, the square unit 320 may be replaced with an absolute pack extracting unit (not shown) for obtaining an absolute value.

That is, the second embodiment of the present invention adds the digital output signal from the adder 220 and the memory (the other adder 210), which calculates the difference in power by summing the power value P output from the adder 200 and a specific value. In the digital integrator consisting of 230), by digitally controlling the analog instability by the digital integration, very fine adjustment is possible.

In addition, in the first embodiment of the present invention, even when the dynamic range of the received analog intermediate frequency signal is large, fine adjustment is possible in the digital AGC unit 500, so that the wide dynamic range and fine adjustment of the analog intermediate frequency can be simultaneously performed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

As described above, the automatic gain adjusting apparatus in the receiver of the present invention has the effect of enabling a wide dynamic range and fine adjustment of the analog intermediate frequency at the same time.

Claims (9)

A digital integrator for integrating a digital output signal corresponding to a difference between a power value of the digital signal corresponding to a baseband signal and a specific value; An adder for adding an output value output from the digital integrator and a preset target automatic gain control value; And And a multiplier for multiplying the output value from the adder and the digital intermediate frequency signal output from the analog / digital converter for converting the analog intermediate frequency signal into a digital intermediate frequency signal. . The method of claim 1, And the digital integrator comprises an adder and a memory using a digital output signal corresponding to a difference between a power value and a specific value of the digital signal corresponding to the baseband signal. delete The method of claim 1, And a mixed auto gain control unit for controlling the gain of the analog intermediate frequency signal through a negative feedback loop of the digital intermediate frequency signal. The method of claim 4, wherein The mixed automatic gain control unit may include: a digital / analog converter for converting a value corresponding to a difference between a power value and a specific value of the digital intermediate frequency signal into an analog value; An integrator that integrates and outputs the converted analog signal; A control unit adjusting a gain of the analog intermediate frequency signal by using the signal output from the integrator; And And an analog / digital converter for converting the analog intermediate frequency signal output through the control unit into the digital intermediate frequency signal. The method of claim 4, wherein And the mixed auto gain control unit is cascaded with the multiplier. delete delete delete

Images