KR20010076682A - RF module and method for compensating non-linear distortion and stabilizing and maximizing the output of RF band wireless communication transmission section using digital signal processing operation - Google Patents

Abstract

PURPOSE: A method and an RF(Radio Frequency) module for stabilizing and maximizing the output of a radio communication transmitting end of RF band and for correcting nonlinear distortion is provided to improve the characteristic of the output by stabilizing and maximizing the characteristic of a nonlinear component by using an adaptive principle. CONSTITUTION: An attenuator(8) attenuates the signal from an antenna(16), and transmits to a mixer(9). The mixer(9) multiplies the attenuated signal by a carrier frequency to obtain the signal of original size. The second low pass filter(10) filers the output signal from the mixer(9) to transmit to an A/D(Analog/Digital) converter(11). The A/D converter(11) converts the filtered signal, and transmits the feed back signal to a digital signal processor(12). The digital signal processor(12) receives the original signal and the feed back signal, analyzes a difference in frequency domain, and controls the filter coefficient to minimize the difference. The first D/A converter(13) converts an analog control signal from the digital signal processor(12) and transmits to the first low pass filter(3). Each the second and third D/A converters(14,15) converts an analog control signal from the digital signal processor(12) and transmits to the first low pass filter(3) respectively.

Description

RF module and method for compensating non-linear distortion and stabilizing and maximizing the output of RF band wireless communication transmission section using digital signal processing operation}

The present invention relates to an RF module to which the output stabilization, maximization and nonlinear distortion compensation techniques of an RF band wireless communication transmitter using digital signal processing are applied. In particular, a method of stabilizing and maximizing the output of a wireless communication transmitter and a digital signal processor are provided. RF band radio using digital signal processing operation for nonlinear distortion compensation of wireless communication transmitter to automatically compensate for nonlinear characteristics of parts of wireless communication transmitter such as power amplifier and filter. The present invention relates to an RF module that applies output stabilization, maximization, and nonlinear distortion equalization techniques of a communication transmitter.

1 shows a configuration diagram of a conventional wireless communication transmitter.

The existing wireless communication transmitter consists of a D / A converter, a low pass filter (LPF), a mixer, a band pass filter (BPF), several power amplifiers, and an antenna.

The operation of the wireless communication transmitter circuit will be described with reference to FIG. 1 as follows.

The digital signal modulated at the baseband modulation stage is converted into an analog signal through a D / A converter and provided to a low pass filter (LPF). The low pass filtered signal is loaded on a carrier frequency through a mixer. give.

When the data on the carrier frequency is passed back through the band pass filter (BPF) to the power amplifier, the power amplification stage having multiple power amplifiers amplifies the signal with sufficient power to be transmitted wirelessly, and then the signal is sufficiently amplified. It is sent out through. In this case, since a single power amplifier has a limited gain width in the power amplifier stage, several power amplifiers may be used to obtain a large output.

However, the problem of the conventional wireless communication transmitter is that the characteristics of the components used in the wireless communication transmitter such as the filter and the power amplifier are non-linear, so the performance of the wireless communication transmitter depends on the characteristics of the components, and the components having the linear characteristics are very Due to the high price, the price of the transmitter is increased, and the power amplifier has a problem that it is difficult to make an efficient amplifier by limiting the amplification degree by using only the band having the linear amplification characteristic for the actual amplification due to the nonlinear amplification characteristic. .

The present invention has been proposed to solve the above problems of the prior art, an object of the present invention is to stabilize the output using the adaptive principle of the characteristics of the non-linear components in the output stabilization and maximization method of the RF band wireless communication transmitter and Economical wireless communication with stable output characteristics without the use of expensive linear components by suggesting maximized wireless transmitter and using digital signal processing processor to be less affected by component characteristics in wireless transmitter design The present invention provides an RF module that applies output stabilization, maximization and nonlinear distortion compensation of RF band wireless communication transmitter using digital signal processing operation.

Another object of the present invention is to provide a method for maximizing output and nonlinear distortion compensation of a wireless communication transmitter, which is particularly suitable for implementing the apparatus.

1 is a block diagram of a conventional wireless communication transmitter.

Figure 2 is a block diagram of a wireless communication transmitter for stabilizing and maximizing the output of the RF band wireless communication transmitter according to the first embodiment of the present invention.

Figure 2 of Figure 3 (a) is an adjustable low pass filter, (b) is an adjustable band pass filter.

4 is a flow chart illustrating the operation of the digital signal processing processor in FIG.

5 is a configuration diagram of a wireless communication transmitter for stabilizing and maximizing output of an RF band wireless communication transmitter according to a second embodiment of the present invention.

6 is a flow chart illustrating the operation of the digital signal processing processor in FIG.

Explanation of symbols on the main parts of the drawings

1: Digital Filter Part 2: D / A Converter

3: first low pass filter (LPF) 4: mixer

5: first band pass filter (BPF) 6: power amplifier

7 second band pass filter 8 attenuator

9: frequency converter (mixer) 10: second low pass filter (LPF)

11: A / D Converter 12: DSP Processor

13: first D / A converter 14: second D / A converter

15: third D / A converter 16: antenna

In order to achieve the above object, the present invention provides a D / A converter (2), a first low pass filter (LPF) (3), a mixer (10) for converting an original signal digitally modulated at a baseband modulation stage into an analog modulated signal. 4) RF radio communication comprising a first band pass filter (BPF) 5, a power amplifier 6 that amplifies the power enough to be transmitted wirelessly, a second band pass filter 7, and an antenna 16 A transmission system comprising: an attenuator (8) for attenuating a signal radiated from an antenna by an amplified magnitude to provide an attenuated signal; A frequency converter (mixer) 9 for receiving the attenuated signal and multiplying the carrier frequency again; A second low pass filter (10) for receiving the output signal from the frequency converter (9) to provide a second low pass filtered signal; An A / D converter (11) for receiving the second low-pass filtered signal and performing A / D conversion to provide a feedback signal; Filter coefficients A, B, and C so that the difference between the original signal and the feedback signal is minimized by analyzing the difference in the frequency domain in order to receive the digitally modulated original signal and the feedback signal and prevent distortion caused by nonlinear characteristics. A DSP processor 12 for providing an analog control signal to the first low pass filter 3, the first band pass filter 5, and the second band pass filter 7, respectively; R and C characteristics of the first low pass filter 3 by receiving an analog control signal from the DSP processor 12 and performing D / A conversion to provide the first control signal to the first low pass filter 3. A first D / A converter 13 for adjusting the filter coefficient A by means of low pass filtering; The analog control signal is received from the DSP processor 12 and subjected to D / A conversion to provide the second control signal to the first bandpass filter 5 to adjust filter coefficient values B according to R and C characteristics. A second D / A converter 14 to allow only a frequency of a specific band to pass through; And receiving an analog control signal from the DSP processor 12 and performing D / A conversion to provide the third control signal to the second band pass filter 7 to obtain filter coefficient values C according to R and C characteristics. It is composed of a third D / A converter (15) for adjusting only the frequency of a specific band by adjusting the output stabilization, maximization and nonlinear distortion compensation of the RF band wireless communication transmitter using digital signal processing operation Provides an RF module.

In order to achieve the above object, the present invention provides the A, B, C filters of the first low pass filter 3, the first band pass filter 5, and the second band pass filter 7 in the DSP processor 12. Initializing a coefficient (S1); Checking the coincidence of the original signal and the feedback signal (S2) and if not matching, adjusting the A, B, C filter coefficients according to the control signal (S3), and repeatedly executing the original signal and the feedback signal to coincide; And transmitting the stable data of the RF band through the antenna by correcting the distortion caused by the nonlinear characteristic using the adjusted filter coefficients A, B, and C. The present invention provides a method for stabilizing, maximizing, and nonlinear distortion of an RF band wireless communication transmitter.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

RF (Radio Frequency) range to which the present invention is applied is 902 ~ 928MHz, 2.4 ~ 2.4835 GHz, 5.725 ~ 5.825 GHz ISM (Industrial, Scientific, and Medical) band and can be applied to other RF wireless communication band, wireless communication By applying digital signal processing (DSP) processors to power amplifiers and filters used for transmission, it is a method of obtaining stable output as well as more efficient output characteristics.

Here, the DSP processor includes a DSP for performing digital signal processing operations, an application specific IC (ASIC), a reduced instruction set computer (RISC) processor, and the like.

The feedback part converting the signal output from the wireless communication transmitter to the antenna 16 back to the original signal and handing it to the DSP processor 12 is added, and the signal extracted from the original signal and the signal radiated to the antenna 16 is added. The digital signal processing processor for comparing and analyzing the data, and correcting the same, and the filter coefficients obtained from the digital signal processing processor 12 may be applied.

2 is a diagram illustrating an RF wireless communication transmitter for stabilizing and maximizing output of an RF band wireless communication transmitter according to a first embodiment of the present invention, a D / A converter (2), a first low pass filter (LPF), and a mixer. (4), first band pass filter (BPF) (5), power amplifier (6), second band pass filter (BPF) (7), attenuator (8), frequency converter (mixer) (9), second Low pass filter 10, A / D converter 11, DSP processor 12, first D / A converter 13, second D / A converter 14, third D / A converter 15 And an antenna 16.

The D / A converter 2 converts the original signal digitally modulated at the baseband modulation stage into D / A conversion into an analog modulated signal and provides it to the first low pass filter 3.

The first low pass filter (LPF) 3 receives the analog modulated signal as shown in FIG. 3A and adjusts the filter coefficient A according to R and C characteristics by a first control signal applied from the outside. To provide a first low-pass filtered signal to the mixer 4.

The mixer 4 serves to load the first low-pass filtered modulated signal at a carrier frequency.

The first band pass filter (BPF) 5 is a second externally applied to remove unnecessary images when receiving the data carried on the carrier frequency as mixed in the mixer 4 as shown in Figure 3b The filter coefficients B according to R and C characteristics are adjusted by a control signal to pass only a frequency of a specific band to provide a first band filtered signal to the power amplifier 6.

The power amplifier 6 includes a plurality of power amplifiers, and amplifies the amplified signal with sufficient power to receive the first band-filtered signal and to transmit the wireless signal to the second band pass filter 7. To provide.

The second bandpass filter 7 receives the amplified modulated signal as shown in FIG. 3B to a third control signal externally applied to remove noise generated by non-linearity. By adjusting the filter coefficient (C) according to the characteristics of each component (R, C) to provide a second band filtered signal to the antenna 16 to pass only the frequency of a specific band.

The attenuator 8 receives the signal radiated from the antenna 16 and attenuates the signal by an amplified magnitude to provide the attenuated signal to the frequency converter (mixer) 9.

The frequency converter (mixer) 9 receives the attenuated signal and multiplies the carrier frequency to have a magnitude of the original signal.

The second low pass filter 10 receives the output signal from the frequency converter 9 and provides a second low pass filtered signal to the A / D converter 11.

The A / D converter 11 receives the second low-pass filtered signal and performs A / D conversion to provide a feedback signal to the DSP processor 12.

The DSP processor 12 receives the digitally modulated original signal and the feedback signal and analyzes the difference in the frequency domain to prevent distortion due to nonlinear characteristics so that the difference between the original signal and the feedback signal is minimized. The coefficients A, B and C are adjusted to provide analog control signals to the first low pass filter 3, the first band pass filter 5 and the second band pass filter 7, respectively.

The first D / A converter 13 receives an analog control signal from the DSP processor 12 and performs D / A conversion to provide the first control signal to the first low pass filter 3.

The second D / A converter 14 receives an analog control signal from the DSP processor 12 and performs D / A conversion to provide the second control signal to the first band pass filter 5.

The third D / A converter 15 receives an analog control signal from the DSP processor 12 and performs D / A conversion to provide the third control signal to the second band pass filter 7.

When the antenna 16 finally modulates the original signal to a carrier frequency and down converts the signal output to the antenna to have the same characteristics as that of the feedback signal, the antenna 16 overcomes the distortion caused by the nonlinear characteristics of the components. Transmits the modulated signal.

4 is a flowchart illustrating an operation of a digital signal processing processor in FIG. 2.

The DSP processor 12 initializes the A, B, C filter coefficients of the first low pass filter 3, the first band pass filter 5, and the second band pass filter 7 (step S1). If the match between the signal and the feedback signal is checked (step S2), and if it is not matched, the A, B, C filter coefficients are adjusted by the control signal (step S3), and the original signal and the feedback signal are repeatedly executed to match, and then adjusted. Data is transmitted through the antenna using the determined filter coefficients (step S4).

Computing the difference between the original signal d (n) and the fed back signal s (n) yields d (n) -s (n) = e (n). The DSP processor 12 is used to minimize the least mean square error value derived from this error signal e (n).

The voltage applied to the first low pass filter 3, that is, the filter coefficient A value is increased and decreased, and the voltage value at which e (n) is minimized is determined.

After the filter coefficient A value of the first low pass filter (LPF) 3 is determined, the voltage applied to the first band pass filter (BPF) 5, that is, the filter coefficient B value is increased and decreased, thereby minimizing e (n). Find and determine the voltage value.

After the filter coefficient B value of the first band pass filter 5 is determined, the voltage applied to the second band pass filter 7, that is, the filter coefficient C value is increased and decreased to find and determine a voltage value at which e (n) is minimized. .

Referring to FIG. 5, an RF wireless communication transmitter for stabilizing and maximizing output of an RF band wireless communication transmitter according to a second embodiment of the present invention includes a digital filter unit having a filter coefficient D at a baseband terminal in the circuit of FIG. 2. 1) was added.

The digital filter unit 1 receives the digital signal modulated from the baseband modulation stage, repeats the A, B, and C filter coefficient adjustments from the DSP processor 12, and obtains optimized coefficients. The filter coefficient D is adjusted and finally corrected to provide a digitally filtered signal to the D / A converter 2. The remaining operation has already been described in FIG. 2.

At this time, the DSP processor 12 modifies the filter coefficients by outputting coefficients in the form of digital signals to the A, B, and C filters, and the signal passing through the modified filter has a desired characteristic gradually. After repeating the adjustment of the coefficients of the B and C filters to obtain the optimized coefficients, the final correction is performed by adjusting the digital filter coefficient D for the less corrected portion.

6 is a flowchart illustrating an operation of a digital signal processing processor in FIG. 5.

The DSP processor 12 initializes the A, B, C filter coefficients of the first low pass filter 3, the first band pass filter 5, and the second band pass filter 7 (step S6). If the match between the signal and the feedback signal is checked (step S7), and if it is not matched, the A, B, C filter coefficients are adjusted by the control signal (step S8), and the coefficient optimization is checked (step S9). After repeated execution and optimization, the D filter coefficients of the digital filter unit are adjusted (step S10), and finally the signals outputted to the antenna 16 by down-converting (modulating the original signal to the carrier frequency) are fed back. When it has the same characteristic as, the distortion phenomenon caused by the nonlinear characteristic of the component is overcome and a stable modulated output signal is transmitted (step S11).

Therefore, RF coefficients can be avoided by avoiding distortion by overcoming the nonlinear characteristics of each filter without using expensive linear components due to real-time correction of the filter coefficients (A, B, C, D) by the DSP processor. The output of the communication transmitter can be stabilized and maximized.

As described above, the output stabilization, maximization and nonlinear distortion compensation method and RF module of the RF band wireless communication transmitter using the digital signal processing operation according to the present invention can overcome the nonlinear characteristics of the power amplifier used in the wireless communication transmitter. It overcomes the nonlinear characteristics of the low pass filter and the band pass filter to automatically correct the nonlinear distortion of the wireless communication transmitter, and can transmit the output signal of the more stable wireless communication transmitter due to the real time correction by the digital signal processor. In the design of the wireless communication transmitter, the selection of components having non-linear characteristics becomes wider, which has the effect of stabilizing and maximizing the output of the RF band wireless communication transmitter.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (4)

D / A converter (2), first low pass filter (LPF) (3), mixer (4), first band pass filter (BPF) for converting the original signal digitally modulated at the baseband modulation stage into an analog modulated signal (5), an RF wireless communication transmission system comprising a power amplifier (6), a second bandpass filter (7), and an antenna (16) that amplify the power enough to be transmitted wirelessly: An attenuator 8 for attenuating the signal radiated from the antenna by an amplified magnitude to provide an attenuated signal; A frequency converter (mixer) 9 for receiving the attenuated signal and multiplying the carrier frequency again; A second low pass filter (10) for receiving an output signal from the frequency converter (9) to provide a second low pass filtered signal; An A / D converter (11) for receiving the second low-pass filtered signal and performing A / D conversion to provide a feedback signal; Filter coefficients A, B, and C so that the difference between the original signal and the feedback signal is minimized by analyzing the difference in the frequency domain in order to receive the digitally modulated original signal and the feedback signal and prevent distortion caused by nonlinear characteristics. A DSP processor (12) for providing an analog control signal to the first low pass filter (3), the first band pass filter (5), and the second band pass filter (7), respectively; R and C characteristics of the first low pass filter 3 by receiving an analog control signal from the DSP processor 12 and performing D / A conversion to provide the first control signal to the first low pass filter 3. A first D / A converter 13 for adjusting the filter coefficient A by means of low pass filtering; The analog control signal is input from the DSP processor 12 and D / A converted to provide the second control signal to the first bandpass filter 5 to adjust the filter coefficient value B according to R and C characteristics. A second D / A converter 14 to allow only a frequency of a specific band to pass through; And The analog control signal is input from the DSP processor 12 and D / A converted to provide the third control signal to the second bandpass filter 7 to adjust the filter coefficient value C according to R and C characteristics. RF to which the output stabilization, maximization and nonlinear distortion compensation techniques of the RF band wireless communication transmitter using digital signal processing, characterized in that it consists of a third D / A converter 15 to pass only the frequency of a specific band module. In the DSP processor 12, initializing the A, B, C filter coefficients of the first low pass filter 3, the first band pass filter 5, and the second band pass filter 7 (S1); Checking the coincidence of the original signal and the feedback signal (S2) and if not matching, adjusting the A, B, C filter coefficients according to the control signal (S3), and repeatedly executing the original signal and the feedback signal to coincide; And By using the adjusted filter coefficients (A, B, C) to correct the distortion due to nonlinear characteristics, and transmitting the stable data of the RF band through the antenna (S4) Output stabilization, maximization and nonlinear distortion compensation method of RF band wireless communication transmitter. D / A converter (2), first low pass filter (LPF) (3), mixer (4), first band pass filter (BPF) for converting the original signal digitally modulated at the baseband modulation stage into an analog modulated signal (5), in a wireless communication transmission system having a power amplifier (6), a second bandpass filter (7), and an antenna (16) that amplify the power enough to be transmitted wirelessly: After receiving the digitally modulated original signal from the baseband modulation stage, the A, B, and C filter coefficients are repeated from the DSP processor 12 to obtain optimized coefficients. A digital filter (1) for finally correcting and providing a digitally filtered signal to the D / A converter (2); An attenuator 8 for receiving the signal radiated from the antenna and attenuating the signal by an amplified amount to provide the attenuated signal; A frequency converter (mixer) 9 for receiving the attenuated signal and multiplying the carrier frequency again; A second low pass filter (10) for receiving the output signal from the frequency converter (9) to provide a second low pass filtered signal; An A / D converter (11) for receiving the second low-pass filtered signal and performing A / D conversion to provide a feedback signal; Filter coefficients A, B, and C so that the difference between the original signal and the feedback signal is minimized by analyzing the difference in the frequency domain in order to receive the digitally modulated original signal and the feedback signal and prevent distortion caused by nonlinear characteristics. A DSP processor (12) for providing an analog control signal to the first low pass filter (3), the first band pass filter (5), and the second band pass filter (7), respectively; R and C characteristics of the first low pass filter 3 by receiving an analog control signal from the DSP processor 12 and performing D / A conversion to provide the first control signal to the first low pass filter 3. A first D / A converter 13 for adjusting the filter coefficient A by means of low pass filtering; The analog control signal is received from the DSP processor 12 and subjected to D / A conversion to provide the second control signal to the first bandpass filter 5 to adjust filter coefficient values B according to R and C characteristics. A second D / A converter 14 to allow only a frequency of a specific band to pass through; And The analog control signal is received from the DSP processor 12 and subjected to D / A conversion to provide the third control signal to the second bandpass filter 7 to adjust the filter coefficient value C according to R and C characteristics. RF to which the output stabilization, maximization and nonlinear distortion compensation techniques of the RF band wireless communication transmitter using digital signal processing, characterized in that it consists of a third D / A converter 15 to pass only the frequency of a specific band module. The DSP processor 12 initializes the A, B, C filter coefficients of the first low pass filter 3, the first band pass filter 5, and the second band pass filter 7 (S6), and then the original signal. Checking the match between the feedback signal and (S7) and adjusting the A, B, and C filter coefficients according to the control signal (S8) if they do not match; And If the coefficient optimization is checked (S9), if not optimized, it is repeatedly executed after the step S7, and if optimized, the D filter coefficient of the digital filter unit is adjusted (S10). Finally, the original signal is modulated to the carrier frequency and output to the antenna 16. When the down conversion has the same characteristics as the signal fed back to overcome the distortion caused by the non-linear characteristics of the component and sends a stable modulated output signal (S11) characterized in that the digital signal processing operation Output stabilization, maximization and nonlinear distortion compensation method of RF band wireless communication transmitter.