KR20140122702A - Bandpass sampling receiver - Google Patents

Abstract

A bandpass sampling receiver of the present invention comprises: an analog-to-digital converter for converting an analog wireless signal into a digital baseband signal; a complex baseband signal extracting unit for generating a first path signal and a second path signal from the digital baseband signal and extracting a complex baseband signal by using a relative sample delay difference between the first path signal and the second path signal. The first path signal is composed of a down-sampled signal after sample-delaying the digital baseband signal, and the second path signal is composed of a down-sampled signal without sample-delaying the digital baseband signal. Also, the complex baseband signal extracting unit comprises: a first delay line for sample-delaying the digital baseband signal converted by the analog-to-digital converter; a first down-sampler for down-sampling the delayed result of the first delay line to generate the first path signal; a second down-sampler for down-sampling the digital baseband signal converted by the analog-to-digital converter to generate the second path signal; a first digital filter for filtering the first path signal; a second digital filter for filtering the second path signal; and an adder for adding the filtered result of the first digital filter and the filtered result of the second digital filter to output the complex baseband signal.

Description

[0001] BANDPASS SAMPLING RECEIVER [0002]

The present invention relates to a wireless signal receiver that can be used in wireless communications, and more particularly to a wireless signal receiver using bandpass sampling techniques.

With the trend toward miniaturization of wireless communication systems, there is an increasing demand for next generation wireless communication receivers with flexibility, adaptability and cognitivity. In order to satisfy such a demand, a receiver design technique (hereinafter, referred to as " receiver design technique ") is proposed in which an analog-to-digital converter (ADC) is designed as close to an antenna as possible and a frequency conversion and demodulation function is performed using a digital signal processor Is required. As a next-generation wireless communication receiver satisfying these conditions, a band-pass sampling receiver is in the spotlight. Bandpass sampling receivers can provide good performance in terms of reconfigurability of the received signal and multi-band / multi-mode reception.

A typical band pass sampling receiver may receive an analog RF signal through an antenna and extract an analog signal of a predetermined band through an analog bandpass filter. The extracted predetermined band of analog signals can be amplified through a low noise amplifier (LNA) and then converted into a digital form of baseband signal through an analog-digital converter (ADC). Since the band-pass sampling receiver does not use analog devices such as a mixer and a local oscillator, it can provide flexible low-cost and compact wireless communication receivers. However, the conventional band-pass sampling receiver has a limitation in down-converting the received analog RF signal to the digital form of the baseband signal only when the carrier frequency is multiplied by an integral multiple of the sample rate in receiving a single RF signal have.

Therefore, when receiving a signal located in an arbitrary frequency band using a conventional band-pass sampling receiver, the sample rate should be determined such that aliasing does not occur in the base band after digital conversion. However, it is very complicated to determine the sample rate at which the aliasing does not occur, and there are many cases where there is no sample rate solution to prevent aliasing from occurring. Therefore, there is a limit to receiving an RF signal located in an arbitrary frequency band using a conventional band-pass sampling receiver.

Meanwhile, in recent years, there has been an increasing demand for accommodating at least two different communication standard signals through a single wireless receiver. In particular, a communication method such as a software-defiend radio (SDR) communication system requires a function capable of receiving an arbitrary frequency band signal. However, existing receivers must have independent receiver circuits or chips for each mode and for each frequency band or channel. Therefore, there is a problem that the circuit structure of the receiver is complicated and the unit price is expensive. Therefore, a new type of receiver capable of supporting multi-band, multi-mode using a single receiver circuit is required.

It is therefore an object of the present invention to provide a band-pass sampling receiver capable of flexibly applying a sample rate while reducing hardware complexity.

It is another object of the present invention to provide a bandpass sampling receiver that is receivable for all frequency bands and signal bandwidths.

It is another object of the present invention to provide a band-pass sampling receiver capable of effectively removing aliasing generated in a baseband while using a single analog-to-digital converter.

It is yet another object of the present invention to provide a bandpass sampling receiver capable of preventing relative delay time errors between signal paths.

A band pass sampling receiver according to an embodiment of the present invention includes an analog-to-digital converter for converting an analog radio signal to a digital baseband signal; A complex baseband signal extractor for generating a first path signal and a second path signal from the digital baseband signal and extracting a complex baseband signal using a relative sample delay difference between the first and second path signals; .

In an embodiment, the first path signal is a signal obtained by applying a sample delay and a downsampling operation to the digital baseband signal, and the second path signal is a signal obtained by applying a downsampling operation to the digital baseband signal.

The complex baseband signal extracting unit may include a first delay unit that samples the digital baseband signal converted by the analog-to-digital converter; A first down-sampler for down-sampling the delay result of the first delay to generate the first path signal; A second downsampler for down-sampling the digital baseband signal converted by the analog-to-digital converter to generate the second path signal; A first digital filter for filtering a first path signal to which the sample delay and downsampling operations are applied; A second digital filter for filtering the second path signal to which the downsampling operation is applied, and an adder for adding the filtered result of the first digital filter and the filtered result of the second digital filter to output the complex baseband signal .

In another embodiment, the first path signal is a signal obtained by applying a sample delay and a decimation operation to the digital baseband signal, and the second path signal is a signal to which a decimation operation is applied to the digital baseband signal.

Wherein the complex baseband signal extracting unit comprises: a first delay unit for sample-delaying the digital baseband signal converted by the analog-to-digital converter; A first decimator for pre-filtering and down-sampling the delay result of the first delay unit to generate the first path signal; A second down-sampler for pre-filtering and down-sampling the digital baseband signal converted by the analog-to-digital converter to generate the second path signal; A first digital filter for filtering a first path signal to which the sample delay and decimation operations are applied; A second digital filter for filtering a second path signal to which the decimation operation is applied; And an adder for adding the filtered result of the first digital filter and the filtered result of the second digital filter to output the complex baseband signal.

According to the present invention, one analog-to-digital converter and a complex baseband signal extractor including all digital circuits can be used to extract a baseband complex baseband signal from a received analog RF signal. Therefore, hardware complexity can be reduced, and the size and manufacturing cost of the receiver can be reduced.

In addition, according to the present invention as described above, aliasing generated in the baseband can be effectively removed. Thus, a single analog-to-digital converter can be used to provide more accurate reception for all frequency bands and signal bandwidths. And, despite the use of a single analog-to-digital converter, a flexible sample rate can be applied.

1 is a diagram illustrating an exemplary spectrum of an analog RF signal located in an arbitrary frequency band.
FIG. 2 and FIG. 3 are views schematically showing the overall configuration of a band-pass sampling receiver according to an embodiment of the present invention.
4 is a block diagram illustrating an example of a complex baseband signal extracting unit according to a first embodiment of the present invention.
5 is an exemplary diagram illustrating a spectrum of a first path signal output from a first downsampler;
6 is an exemplary diagram illustrating a spectrum of a second path signal output from a second downsampler;
FIG. 7 is a diagram illustrating a spectrum of a complex baseband signal output from the adder shown in FIG.
FIG. 8 is a diagram illustrating a spectrum of a complex baseband signal output from the digital up / down converter shown in FIG.
9 is a diagram illustrating an example of a detailed configuration of a complex baseband signal extracting unit according to a second embodiment of the present invention.
10 is a diagram illustrating an example of a detailed configuration of a complex baseband signal extracting unit according to a third embodiment of the present invention.
11 is a diagram illustrating a detailed configuration of a complex baseband signal extracting unit according to a fourth embodiment of the present invention.
12 is a diagram illustrating an example of a detailed configuration of a complex baseband signal extracting unit according to a fifth embodiment of the present invention.
FIG. 13 is a diagram illustrating a detailed configuration of a complex baseband signal extracting unit according to a sixth embodiment of the present invention.
FIG. 14 is a flowchart illustrating a method of extracting a complex baseband signal of a band-pass sampling receiver according to an exemplary embodiment of the present invention.
15 is a flowchart illustrating a method of reconstructing a digital filter for extracting a complex baseband signal in a bandpass sampling receiver according to an embodiment of the present invention.
16 and 17 are views schematically showing the overall configuration of a band-pass sampling receiver according to another embodiment of the present invention.
18 is a flowchart illustrating an example of a complex baseband signal extracting method according to another embodiment of the present invention.
19 is a flowchart illustrating an example of a complex baseband signal extracting method according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry out the technical idea of the present invention. The same elements will be referred to using the same reference numerals. Similar components will be referred to using similar reference numerals. The following embodiments can be modified in various forms, and the scope of the present invention is not limited to the embodiments described below.

1 is a diagram illustrating an exemplary spectrum of an analog RF signal located in an arbitrary frequency band.

Referring to FIG. 1, it can be assumed that an analog RF signal has a carrier frequency of f _c and a signal bandwidth of B, and the spectrum of the analog RF signal is composed of a positive frequency spectrum component and a negative frequency spectrum component. 1, R _{AR +} (f) represents the positive frequency spectrum component of the analog RF signal, and R _{AR ??} (f) represents the negative frequency spectrum component of the analog RF signal.

FIGS. 2 and 3 are views schematically showing the overall configuration of the band-pass sampling receivers 100_1 and 100_2 according to an embodiment of the present invention.

2, the bandpass sampling receiver 100_1 includes an antenna 10, a bandpass filter 20, a low noise amplifier (LNA) 30, an analog-to-digital converter (ADC) 50, A baseband signal extractor 60, a digital up / down converter 80, and a digital signal processor (DSP)

The antenna 10 functions to receive an analog RF signal ARF transmitted wirelessly. The band pass filter 20 may be composed of a wide band band pass filter for filtering a wide band signal. The band-pass filter 20 can be designed so that the pass band is limited to a predetermined bandwidth B, and removes out-of-band noise. In the exemplary embodiment, the passband and the passband B set in the bandpass filter 20 may have a fixed value and may be adjusted to other values. For this purpose, the bandpass filter 20 may be a tunable BPF.

The low noise amplifier 30 generates an analog RF signal AR ₁₂ whose filtering result ARB of the bandpass filter 20 is amplified by a predetermined gain.

The analog-to-digital converter 50 converts the analog RF signal AR ₁₂ provided from the low noise amplifier 30 into a digital baseband signal DR ₁₂ . For example, the analog-to-digital converter 50 converts the analog RF signal AR ₁₂ provided from the low noise amplifier 30 into a digital baseband signal DR ₁₂ having a sample rate of f _S. The spectrum of the digital baseband signal DR ₁₂ converted through the analog-to-digital converter 50 is composed of the sum of the spectral components transited from the positive frequency band and the spectrum components of the negative transition from the negative frequency band .

As shown in FIG. 2, a single analog-to-digital converter 50 may be used for the band-pass sampling receiver 100_1 of the present invention. The configuration of the complex baseband signal extracting unit 60 for extracting the complex baseband signal may be configured by a digital circuit. Therefore, the hardware complexity is reduced as compared with the conventional band-pass sampling receiver. Here, the detailed configuration of the complex baseband signal extracting unit 60 to be applied to the present invention is not limited to a specific form and can be variously modified and modified. For example, the detailed configuration of the complex baseband signal extracting unit 60 according to the present invention may be configured in various forms, such as the complex baseband signal extracting unit 60_160_6 according to the first to sixth embodiments described below .

The complex baseband signal extractor 60 extracts a first path signal (see DR _{A in} FIG. 4) and a sample delay (see FIG. 4) from the digital baseband signal DR ₁₂ converted by the analog- (See DR _{B in} Fig. 4). Then, the digital filter is designed based on the phase difference resulting from the relative sample delay difference between the first and second path signals DR _A and DR _B , so that a transition from the positive frequency band to the spectral component or from the negative frequency band The spectral components are extracted.

According to the configuration of the complex baseband signal extracting unit 60 of the present invention, even if the positive frequency spectrum component and the negative frequency spectrum component are aliased in the baseband, the aliasing effect is removed, . That is, even though a single analog-to-digital converter 50 is used, a complex baseband signal having a positive frequency spectrum component from the positive frequency band or a complex baseband signal having a complex frequency spectrum component having a negative frequency spectrum component transited from the negative frequency band The baseband signal can be perfectly extracted. Thus, as compared to conventional bandpass sampling receivers where the sample rate is limited to a specific sample rate, the sample rate can be selected more flexibly and reception is possible for all frequency bands and signal bandwidths.

The center frequency of the complex baseband signal extracted by the complex baseband signal extractor 60 is determined by the carrier frequency f _c and the sample rate f _s of the analog RF signal and may be 0 or 0 Maybe not. When the center frequency of the complex baseband signal extracted by the complex baseband signal extractor 60 is not 0, the center frequency of the complex baseband signal may be shifted to 0 through the digital up / down converter 80 . If the center frequency of the complex baseband signal extracted by the complex baseband signal extractor 60 is 0, the configuration of the digital up / down converter 80 for shifting the center frequency of the complex baseband signal to 0 is omitted (See Figs. 18 to 20). Baseband signal processing (e.g., demodulation operation, etc.) for a complex baseband signal with a center frequency of zero is performed through the digital signal processor 90.

Meanwhile, the complex baseband signal extracted by the complex baseband signal extractor 60 may be a complex baseband signal DR ₁ having a positive frequency spectrum component shifted from a positive frequency band, And may correspond to a complex baseband signal DR ₁ having a frequency spectrum component of a transition. For convenience of explanation, the complex baseband signal extractor 60 removes a negative frequency spectrum component shifted from the negative frequency band and generates a complex baseband signal having a positive frequency spectrum component shifted from the positive frequency band, The extraction of the band signal DR ₁ will be described by way of example. However, this is an example to which the present invention is applied. The configuration of the complex baseband signal extracted by the complex baseband signal extracting unit 60 is not limited to a specific form, but can be variously modified and modified.

3, the bandpass sampling receiver 100_2 of the present invention may further include a track and holder 40 in addition to the configuration of the bandpass sampling receiver 100_1 shown in FIG. 2 . The bandpass sampling receiver 100_2 shown in FIG. 3 is substantially the same as the bandpass sampling receiver 100_1 shown in FIG. 2 in the rest of the configuration except for the track and holder 40. Therefore, the same reference numerals are assigned to the same components, and redundant description of the same components will be omitted below.

Although not shown in FIG. 3, the track-and-holder 40 may be comprised of an analog switch and a sampling capacitor. When the switch is closed, the track & holder 40 is operated as a track mode for tracking the input signal. Then, when the switch is opened, the track & holder 40 operates as a hold mode. In the hold mode, the track & holder 40 keeps the last instantaneous value of the input to the sampling capacitor. According to the operation of the track and holder 40 in the track mode and the hold mode, the analog-to-digital conversion band to be processed in the analog-to-digital converter 50 can be increased.

According to the configuration of the band-pass sampling receivers 100_1 and 100_2 described in FIGS. 2 and 3, the band-pass sampling receivers 100_1 and 100_2 of the present invention use a single analog-to- And directly downconverts the analog RF signal to a digital baseband signal. The band-pass sampling receivers 100_1 and 100_2 of the present invention generate a frequency spectrum having a positive frequency spectrum and a negative frequency spectrum transited from the negative frequency band constituting the digital baseband signal DR ₁₂ , The aliasing can be removed through the complex baseband signal extractor 60 even if the components are aliased in the baseband and mutual interference occurs. Therefore, it is possible to accurately extract the complex baseband signal DR ₁ without having to redesign the receiver according to the frequency band. In addition, since most of the band-pass sampling receivers 100_1 and 100_2 of the present invention are constituted by digital circuits, the structure of the receiver is very simple and the price is very low. Therefore, the hardware complexity of the receiver can be reduced, and the size and manufacturing cost of the receiver can be reduced.

4 is a diagram illustrating an example of a detailed configuration of a complex baseband signal extracting unit 60_1 according to the first embodiment of the present invention.

4, the complex baseband signal extractor 60_1 includes a first delay 610, first and second down samplers 611 and 612, first and second digital filters 615 and 616 ), And an adder 619.

The first delay 610 delays the digital baseband signal DR ₁₂ output from the analog-to-digital converter 50 by D samples. Where the sample delay value D has an integer value that is greater than zero and less than the down sample rate (N). The D-sampled delayed signal through the first delay 610 is downsampled through the first down-sampler 611 such that the sample rate is 1 / N times. The first path signal DR _A , which is the output signal of the first downsampler 611, is provided to the first digital filter 615.

The digital baseband signal DR ₁₂ output from the analog-to-digital converter 50 is given as a second downsampler 612 input without sample delay to generate a second path signal DR _B. The digital baseband signal DR ₁₂ output from the analog-to-digital converter 50 is downsampled through the second downsampler 612 such that the sample rate is 1 / N times. The second path signal DR _B output from the second downsampler 612 is provided to the second digital filter 616. Here, the sample rate f ' _S of the signal output from the first and second downsamplers 611 and 612 is f _S / N. According to the configuration of the present invention, the first path signal DR _A and the second path signal DR _B output from the first and second down-samplers 611 and 612 have a D / N There is a relative sample delay difference.

)을 예시적으로 보여주는 도면이다. 또한, 도 6은 도 4에 도시된 제 2 다운 샘플러(612)로부터 출력된 제 2 경로 신호(DR_B)의 스펙트럼(

)을 예시적으로 보여주는 도면이다.FIG. 5 is a graph showing the spectrum of the first path signal DR _A output from the first downsampler 611 shown in FIG.

As shown in FIG. 6 also shows the spectrum of the second path signal DR _B output from the second downsampler 612 shown in FIG.

As shown in FIG.

5 and the spectrum shown in Figure 6, corresponds to the spectrum in the first Nyquist zone (1 ^st Nyquist zone) band. The signal characteristics of the first path signal DR _A and the second path signal DR _B are as follows.

The first path signal DR _A is a signal obtained by downsampling the output signal of the A / D converter 50 after D samples are delayed. On the other hand, the second path signal DR _B is a result signal obtained by down-sampling only the output signal of the A / D converter 50 without performing the sample delay. As a result, the first path signal DR _A may be a signal obtained by delaying the second path signal DR _B by D / f _s (= D / Nf _s '). Therefore, the spectrum of the first path signal DR _A due to the relative time delay becomes the same as the spectrum of the second path signal DR _B including the influence of the group delay.

으로 주어지고, 음의 주파수 대역으로부터 천이한 스펙트럼 성분에 대해서

으로 주어진다. The effect of the group delay due to the time delay of the first path signal DR _A is that the spectral components transited from the positive frequency band

And the spectral components that are transposed from the negative frequency band

.

Here, n is a frequency band position index of the signal and has values of 0, 1, 2, 3,..., And the carrier frequency f _c of the signal and the first and second down converters 611 and 612, (F ' _S = f _S / N) at the output of the comparator 505 as follows.

Here, round () means rounding.

The first and second digital filters 615 and 616 are controlled by using the relative phase difference (the effect of the relative group delay) due to the relative delay time difference between the first path signal DR _A and the second path signal DR _B , Even if aliasing occurs between the positive frequency spectrum component and the negative frequency spectrum component, aliasing can be removed and the desired complex baseband signal DR ₁ can be perfectly extracted.

According to the present invention, by using the first and second digital filters 615 and 616 and the adder 619, a positive frequency spectrum component shifted from the positive frequency band and a negative frequency spectrum component shifted from the negative frequency band A complex baseband signal having a positive frequency spectrum component or a complex baseband signal having a negative frequency spectrum component can be extracted from the added signal.

The design method of the first and second digital filters 615 and 616 according to the present invention is as follows.

)과 제 2 경로 신호(DR_B)의 스펙트럼 (

)은 각각 [수학식 2]와 [수학식 3]으로 표현될 수 있다.5 and 6, the spectrum of the first path signal DR _A within the first Nyquist zone band at the outputs of the first and second down samplers 611 and 612

) And the spectrum of the second path signal DR _B (

Can be expressed by Equations (2) and (3), respectively.

Here, R _?? (f) and R ₊ (f) correspond to a baseband replica spectrum in which the negative frequency and positive frequency spectrum components of the analog RF signal are frequency shifted, respectively.

The spectrum of the first path signal DR _A that has passed through the first digital filter 615 and the spectrum of the second path signal DR _B that has passed through the second digital filter 616 are expressed by Equation 4 and Equation Can be expressed by the following equation (5).

The filtering result of the first path signal DR _A that has passed through the first digital filter 615 and the filtering result of the second path signal DR _B that has passed through the second digital filter 616 are supplied to the adder 619 Lt; / RTI > In an alternative embodiment, the adder 619 may be replaced by a subtractor to be configured to subtract the filtering result of the second digital filter 616 from the filtering result of the first digital filter 615.

The spectrum of the output signal of the adder 619 shown in FIG. 4 can be expressed by Equation (6).

In order for the complex baseband signal extractor 60_1 to remove spectrum components transited from the negative frequency band and obtain only spectral components transited from the positive frequency band, the first and second digital filters 615, It should be designed to satisfy Equation (7).

In order for the first and second digital filters 615 and 616 to satisfy Equation (7), the simultaneous equations given by Equation (8) and Equation (9) must be satisfied.

Solving the simultaneous equations given by [Equation 8] and [Equation 9], H _A (f) corresponding to the frequency response of the first digital filter 615 can be expressed by Equation (10) H _B (f) corresponding to the frequency response of the digital filter 616 can be expressed by Equation (11).

의 동작 속도를 갖는 디지털 필터 형태로 구현 될 수 있다. 또한, [수학식 10]과 [수학식 11]에서 알 수 있듯이,

(여기서, m=정수)을 만족하여야 하며,

을 만족하도록 f_s, D, N을 변경할 수 있다.The obtained H _A (f) and H _B (f)

Lt; RTI ID = 0.0 > digital filter < / RTI > Further, as can be seen from the equations (10) and (11)

(Where m = integer)

A can change the f _s, D, N so as to satisfy.

Then, the coefficients of the digital filter can be recalculated according to the RF frequency band of the received signal, and the digital filter can be reconstructed using the calculated filter coefficients to receive the baseband signal located in any arbitrary frequency band . The reconstruction method of the digital filter according to the present invention will be described in detail below with reference to FIG.

이기 때문에, 제 2 디지털 필터(616)의 임펄스 응답 h_B(t)는, t=0일 경우에 [수학식 12]로 주어지는 상수 C의 값을 갖게 되고, t0인 경우에는 0의 값을 갖게 된다. 따라서, 제 2 디지털 필터(616)는 샘플 지연기와 상수 C 만큼의 이득을 제공하는 이득기(gain adjustment logic)로 대체될 수 있다(도 12 내지 도 15 참조). 여기서 샘플 지연기의 샘플 지연 동작은, 제 1 다운 샘플러(611)가 다운샘플링 결과를 출력하는 시간으로부터 제 1 디지털필터(615)가 필터링 결과 신호를 출력할 때까지 소요되는 시간 만큼을 보상한 것에 해당된다. 제 2 디지털 필터(616)가 샘플 지연기와 이득기로 대체되는 경우, 회로 구성은 더욱 간단해질 것이다. 간단해진 회로 구성으로 인해, 수신기의 사이즈와 제조 단가가 줄어들게 될 것이다.As can be seen from Equation (11), H _B (f) corresponding to the second digital filter 616 is a constant and not a function of frequency, and the operation speed of the second digital filter 616 is

The impulse response h _B (t) of the second digital filter 616 has a constant C value given by Equation (12) when t = 0 and a value of 0 when it is t0 do. Thus, the second digital filter 616 may be replaced by a gain delay logic and a gain delta that provides a constant C (see Figures 12-15). Here, the sample delay operation of the sample delay unit compensates for the time required from the time when the first down-sampler 611 outputs the down-sampling result to the time when the first digital filter 615 outputs the filtering result signal . If the second digital filter 616 is replaced by a sample delay and a gain, the circuit configuration will be further simplified. Due to the simpler circuit configuration, the size and manufacturing cost of the receiver will be reduced.

FIG. 7 is an exemplary diagram illustrating the frequency response S (f) of the complex baseband signal DR ₁ output from the adder 619 shown in FIG.

4 and 7, the filtering result S _A of the first path signal that has passed through the first digital filter 615 and the filtering result S ( _A ) of the second path signal that has passed through the second digital filter 616 _B ) is added through the adder 619, the spectral component R _- (f) that has been shifted from the negative frequency band is removed and only the spectral component R ₊ (f) It remains. Thus, it is possible to remove the aliasing and extract the desired complex baseband signal DR ₁ .

The center frequency of the complex baseband signal DR ₁ output through the adder 619 may not have a value of 0 as shown in FIG. For example, the center frequency of the complex baseband signal DR ₁ may be less than zero or greater than zero. In this case, the center frequency of the complex baseband signal DR ₁ may be up / down converted by the digital up / down converter 80 and adjusted to zero. The digital up / down conversion operation performed in the digital up / down converter 80 can be expressed by Equation (13).

Here, s (t) denotes the complex baseband signal DR ₁ output through the adder 619, and f _if denotes an intermediate frequency of the complex baseband signal DR ₁ output from the adder 619 , Which can be obtained by Equation (14).

According to the digital up / down conversion operation of the digital up / down converter 80 expressed by Equation (13), the center frequency of the complex baseband signal DR ₁ outputted through the adder 619 can be adjusted to zero have. The complex baseband signal DR ₁ 'output from the digital up / down converter 80 is input to the digital signal processor 90. The digital signal processor 90 performs baseband signal processing on the input complex baseband signal DR ₁ '. The baseband signal processing performed in the digital signal processor 90 may include a demodulation operation or the like.

If the center frequency of the complex baseband signal DR ₁ output through the adder 619 is zero (i.e., the center frequency of the analog RF signal is an integer multiple of the sample rate), the band- The configuration of the digital up / down converter 80 at the receiver may be omitted (see Figs. 16 and 17).

The configuration of the complex baseband signal extracting unit 60_1 of the present invention described above is not limited to a specific form and can be changed and modified in various forms. A modification of the complex baseband signal extracting unit 60_1 according to the present invention is as follows.

8 is an exemplary diagram illustrating a frequency response S '(f) of an up / down converted first complex baseband signal DR1 output from the digital up / down converter 80 shown in Fig. 3 . Referring to FIG. 8, the intermediate frequency of the first complex baseband signal DR1 output from the adder 619 may be converted up / down through the digital up / down converter 80.

The center frequency of the complex baseband signal DR ₁ output through the adder 619 may be less than zero or greater than zero. However, according to the digital up / down conversion operation performed in the digital up / down converter 80, the complex baseband signal DR ₁ can be adjusted to the first complex baseband signal DR1. According to the frequency response S '(f) of the first complex baseband signal DR1, it can be seen that the center frequency has been adjusted to zero. That is, the center frequency of the complex baseband signal DR ₁ may be up / down converted by the digital up / down converter 80 and adjusted to zero.

FIG. 9 is a diagram illustrating a detailed configuration of a complex baseband signal extracting unit 60_2 according to a second embodiment of the present invention.

Referring to FIG. 9, the first downsampler 611 of FIG. 4 may be replaced by a first decimator 1 613, and the second downsampler 612 of FIG. 4 may be replaced by a second decimator decimator 2) < / RTI > Each of the first and second decimators 613 and 614 may be comprised of a pre-digital filter and a downsampler, wherein the sample rate of the output signal is 1 / N (N is greater than 1 Integer) times. The pre-filtering and down-sampling operations of the first and second decimators 613 and 614 may correspond to the down-sampling operation of the first and second down-samplers 611 and 612.

The remaining components except for the first and second decimators 613 and 614 in the complex baseband signal extractor 60_2 shown in FIG. 9 are substantially the same as the complex baseband signal extractor 60_1 shown in FIG. 4 same. Therefore, the same reference numerals are assigned to the same components, and redundant description of the same components will be omitted below.

FIG. 10 and FIG. 11 illustrate detailed configurations of the complex baseband signal extracting units 60_3 and 60_4 according to the third and fourth embodiments of the present invention.

Referring to FIGS. 10 and 11, the second digital filter 616 of FIG. 4 may be replaced by a second delay 617 and gain adjustment logic 618 which provides a predetermined gain. The second delay 617 is configured to delay Y sample the second path signal DR _B. The sample delay operation of the second delay compensates for the time it takes from the time the first downsampler 611 outputs the downsampling result to the time the first digital filter 615 outputs the filtered result signal . In this case, the time taken for the first digital filter 615 to output the filtering result signal may actually correspond to the time required for the filtering operation of the first digital filter 615. Therefore, the sample delay value Y of the second delay can be determined according to the time required for the filtering operation of the first digital filter 615 of the complex baseband signal extractor 60_1.

만큼의 시간 지연이 발생하게 되므로, 샘플 지연 값은

이 되도록 구성될 수 있다. 여기서,

은 X 보다 작은 정수 중 가장 큰 수를 의미한다. 이득기(618)는 제 2 지연기(617)의 샘플 지연 결과(DR_B_D)에 상수 C 만큼의 이득을 인가한다. 이득기(618)의 출력 신호(MR_B_D)는 가산기(619)로 제공된다. 제 1 디지털 필터(615)의 필터링 결과(S_A)와 이득기(618)의 출력 신호(MR_B_D)가 가산기(619)를 통해 더해짐으로 인해, 복소 기저대역 신호 추출부(60_3)의 출력에서 음의 주파수 대역으로부터 천이한 스펙트럼 성분(R_-(f))이 제거되고, 양의 주파수 대역으로부터 천이한 스펙트럼 성분(R₊(f))을 갖는 복소 기저대역 신호(DR₁)만 남게 된다.For example, when the first digital filter 615 of the complex baseband signal extractor 60_1 is implemented as an FIR filter of length L, the FIR filtering operation

So that the sample delay value becomes < RTI ID = 0.0 >

. ≪ / RTI > here,

Means the largest number of integers less than X. The gain 618 applies a constant C gain to the sample delay result DR _{B - D} of the second delay 617. The output signal (MR _{B - D} ) of the gain 618 is provided to an adder 619. In the first output of the digital filter to filter the results of (615) (S _A) and yideukgi 618, the output signal (MR _B _D) is due to deohaejim through the adder 619, the complex baseband signal extraction section (60_3) of The spectral component R _- (f) shifted from the negative frequency band is removed and only the complex baseband signal DR ₁ having the spectral component R ₊ (f) transited from the positive frequency band is left.

The connection order of the second delay 617 and the gain 618 is not limited to a specific type, and the connection order can be interchanged as shown in Figs. 10 and 11. [

If the complex baseband signal extractors 60_3 and 60_4 include the second delay 617 and the gain 618 instead of the second digital filter 616, the circuit configuration will be further simplified. Due to the simpler circuit configuration, the size and manufacturing cost of the receiver will be reduced.

The remaining components of the complex baseband signal extracting units 60_3 and 60_4 shown in FIG. 10 and FIG. 11 except for the second delay 617 and the gain 618 are the complex baseband signal extracting unit 60_1). Therefore, the same reference numerals are assigned to the same components, and redundant description of the same components will be omitted below.

FIG. 12 and FIG. 13 illustrate detailed configurations of complex baseband signal extracting units 60_5 and 60_6 according to fifth and sixth embodiments of the present invention.

Referring to Figures 12 and 13, the first downsampler 611 of Figure 4 may be replaced by a first decimator 613 and the second downsampler 612 of Figure 4 may be replaced by a second decimator 614 ). ≪ / RTI > The first and second decimators 613 and 614 may be configured as a pre-digital filter and a down-sampler, respectively, and the sample rate of the output signal may be adjusted to be 1 / N times the input signal. The pre-filtering and down-sampling operations of the first and second decimators 613 and 614 may correspond to the down-sampling operation of the first and second down-samplers 611 and 612.

The second digital filter 616 of FIG. 4 may then be replaced by a second delay 617 and a gain 618 providing a gain of a constant C.

The connection order of the second delay 617 and the gain 618 is not limited to a specific form, and the connection order can be interchanged as shown in Figs. 12 and 13.

In the complex baseband signal extracting units 60_5 and 60_6 shown in Figs. 12 and 13, the first and second decimators 613 and 614, the second delayer 617, and the gain 618 The configuration is substantially the same as that of the complex baseband signal extractor 60_1 shown in Fig. Therefore, the same reference numerals are assigned to the same components, and redundant description of the same components will be omitted below.

The embodiment of the band-pass sampling receiver as described above is for the case where the complex baseband signal extractor 60, 60_160_6 uses the adder 619 to extract the complex baseband signal DR ₁ . As another embodiment, the adder 619 may be replaced with a subtracter in order that the complex baseband signal extractors 60 and 60_160_6 extract a plurality of baseband signals DR ₁ . According to another embodiment using a subtractor, the complex baseband signal extractors 60 and 60_160_6 may use a first digital filter 615 and a second digital filter 616 to extract the complex baseband signal DR ₁ , Can be designed to satisfy the following equation (15).

The detailed design method of the first digital filter 615 and the second digital filter 616 according to this embodiment is the same as that of the filter design method given by the equations (2) to (12) do.

As another embodiment, the complex baseband signal extractor 60 and 60_160_6 extracts a positive frequency spectrum component from the positive frequency band by the complex baseband signal extractor 60, The complex baseband signal DR ₁ having the frequency spectrum component of the complex baseband signal DR ₁ can be extracted. According to this embodiment, the first digital filter 615 and the second digital filter 616 extract the complex baseband signal DR ₁ from the complex baseband signal extractors 60 and 60 _ 1 _ ] Or [17].

Equation (16) corresponds to the case where the complex baseband signal extractor (60, 60_160_6) uses the adder (619) to extract the complex baseband signal, and Equation (17) It corresponds to the case of using a subtracter to extract.

The detailed design method of the first digital filter 615 and the second digital filter 616 according to this embodiment is the same as that of the filter design method given by the equations (2) to (12) do.

FIG. 14 is a flowchart illustrating a method of extracting a complex baseband signal of a band-pass sampling receiver according to an exemplary embodiment of the present invention. The complex baseband signal extracting method shown in FIG. 14 can be applied to all the bandpass sampling receivers 100, 100_1 and 100_2 including the complex baseband signal extractors 60 and 60_160_6 described above.

14, the band-pass sampling receiver 100, 100_1, 100_2 of the present invention receives the analog RF signal ARF through the antenna 10 (step S1000). The analog RF signal ARF received via the antenna 10 is converted into an analog RF signal ARF having a predetermined bandwidth B and a predetermined carrier frequency f _c through the bandpass filter 20 and the low noise amplifier 30, (AR ₁₂ ). The analog RF signal AR ₁₂ may be converted to a digital baseband signal DR ₁₂ through an analog-to-digital converter 50 (step S1100). The digital baseband signal DR ₁₂ may be composed of a sum of a spectral component shifted from a positive frequency band and a spectrum component shifted from a negative frequency band.

The complex baseband signal extractor 60 or 60_160_6 extracts a first path signal DR _A with a sample delay and a second path signal DR _A without a sample delay from the digital baseband signal DR ₁₂ converted by the analog- 2 path signal DR _B (step S1200).

The first path signal DR _A is a downsampled signal after the digital baseband signal DR ₁₂ is delayed by a D sample and the second path signal DR _B is a signal whose digital baseband signal DR ₁₂ is down It is a sampled signal. The first path signal DR _A and the second path signal DR _B are downsampled through the first and second down samplers 611 and 612 such that the sample rate is 1 / N times. The sample rate f ' _s of down-sampling results output from the first and second down-samplers 611 and 612 is f _s / N. In an exemplary embodiment, the first and second down samplers 611, 612 may be replaced by first and second decimators 613, 614. Each of the first and second decimators 613 and 614 may be comprised of a pre-digital filter and a downsampler, wherein the sample rate of the output signal is 1 / N (N is greater than 1 Integer) times. The pre-filtering and down-sampling operations of the first and second decimators 613 and 614 may correspond to the down-sampling operation of the first and second down-samplers 611 and 612.

The complex baseband signal extractor 60 and 60_160_6 extracts the relative phase difference resulting from the relative sample delay difference between the first path signal DR _A and the second path signal DR _B To extract the complex baseband signal DR ₁ (step S1300).

First complex extraction of the baseband signal (DR _1), the complex baseband signal pickups (61, 60_160_6) a first digital filter 615, a second digital filter 616 (or the second delay (617 provided in the And gain 618), and an adder 619 may be used. The first and second digital filters 615 and 616 may be implemented in the form of a digital FIR filter and the second digital filter 616 may be implemented with a second delay 617 and a gain 618 (See Figs. 10 to 13). The filtering result S _A of the first digital filter 615 and the filtering result S _{B of} the second digital filter 616 (the filtering result of the second digital filter 616 S _B) instead of the spectral components shifted from the negative frequency band at the output of the output of the yideukgi 618) due to the deohaejim through the adder 619, the complex baseband signal pickups (61, 60_160_6) (R _- (f ) Is removed, leaving only the complex baseband signal DR ₁ having the spectral component R ₊ (f) that has shifted from the positive frequency band.

The complex baseband signal DR ₁ extracted in step S1300 may be up / down converted by the digital up / down converter 80 so that the center frequency of the complex baseband signal DR ₁ may be shifted to zero (S1400 step). Then, the output signal of the digital up / down converter 80 is provided to the digital signal processor 90 to perform baseband signal processing (e.g., demodulation operation, etc.) (S1500).

According to the complex baseband signal extracting method of the band-pass sampling receiver of the present invention described above, even when the spectral components shifted from the positive frequency band and the spectrum components shifted from the negative frequency band are aliased in the baseband, And the complex baseband signal DR ₁ having a positive spectral component or a negative spectral component can be perfectly extracted. In other words, despite the use of a single analog-to-digital converter, the sample rate can be chosen more flexibly than for conventional band-pass sampling receivers where the sample rate is limited at a certain sample rate, and for all frequency bands and signal bandwidths Reception becomes possible.

In addition, only one analog-to-digital converter 50 may be used in the complex baseband signal extractor 60, 60_160_6 of the present invention, and a configuration for extracting the complex baseband signal may be all composed of a digital circuit. Therefore, the hardware complexity is reduced as compared with the conventional band-pass sampling receiver.

FIG. 15 is a flowchart illustrating a method of reconstructing digital filters 615 and 616 for extracting a complex baseband signal in a band-pass sampling receiver according to an embodiment of the present invention. The reconstruction method of the digital filters 615 and 616 shown in FIG. 15 can be applied to both of the complex baseband signal extractors 60 and 60_160_6 described above and the bandpass sampling receiver including the same.

The band-pass sampling receiver according to the present invention is not limited to signals in a specific frequency band, but can receive RF signals located in an arbitrary frequency band. The functions of the filters of the first and second digital filters 615 and 616 given by the equations (7) to (11) are determined according to the frequency band (or the carrier frequency) of the analog RF signal. Thus, each of the digital filters 615 and 616 can be flexibly reconfigured so that the bandpass sampling receiver according to the present invention can accommodate any frequency band signal.

The filter coefficients of the first and second digital filters 615 and 616 are determined by the sampling rate f _S of the analog-to-digital converter 50, the frequency band location index n of the analog RF signal AR ₁₂ , The sample delay value D of the first delay 610 and the down sampling rate N of the first down sampler 611 and the second down sampler 612 The digital filter coefficients of each of the first digital filter 615 and the second digital filter 616 are recalculated and the recalculated first digital filter 615 and the second digital filter 616 Each of the first digital filter 615 and the second digital filter 616 can be flexibly reconfigured based on the respective digital filter coefficients.

Referring to FIG. 15, the method for reconstructing the first and second digital filters 615 and 616 according to the present invention includes first, as a filtering parameter, a carrier frequency f _c , a sample rate f _S , The sample delay value D of the first down sampler 610 and the down sampling rate N of the first and second down samplers 611 and 612 can be set in step S2000.

Here, the carrier frequency (f _c) denotes the carrier frequency of the analog RF signal (AR _12). The sample rate f _S refers to the sample rate when the analog RF signal AR ₁₂ is converted to the digital baseband signal DR ₁₂ via the analog-to-digital converter 50.

The complex baseband signal extractor 60 extracts a complex frequency spectrum component from the positive baseband signal DR ₁₂ output from the analog-to-digital converter 50, And extracts a complex baseband signal DR ₂ having a negative frequency spectrum component.

The complex baseband signal extractor 60 extracts the complex baseband signal DR ₁ or DR ₂ from the digital baseband signal DR ₁₂ output from the analog- 1 path signal DR _A and a second path signal DR _B without a sample delay.

Specifically, the digital baseband signal DR ₁₂ output from the analog-to-digital converter 50 is delayed by D samples through the first delay unit 610 of the complex baseband signal extractor 60, ₁₂ _D). The delay signal DR ₁₂ _D generated from the first delay unit 610 is down-sampled through the first down-sampler 611 such that the sample rate is 1 / N times and is generated as the first path signal DR _A. The first path signal DR _A generated from the first down-sampler 611 is provided to the first digital filter 615. Where N may be an integer greater than one and the sample delay D may have an integer value that is greater than zero and less than the down sample rate (N).

The digital baseband signal DR _{12 that} has not passed through the first delay 610 is downsampled through the second downsampler 612 so that the sample rate is 1 / N times and is generated as the second path signal DR _B . The second path signal DR _{B is} provided to the second digital filter 616 and the second signal extractor 62. Here, the sample rate f ' _{S of} the first path signal DR _A and the second path signal DR _B is f _S / N. According to the configuration of the present invention, the relative sample delay of D / N between the first path signal DR _A and the second path signal DR _B output from the first and second down samplers 611 and 612, There is a difference (i.e., a relative time delay difference of D / (N f ' _S )).

Subsequently, an n value is calculated as a parameter to be applied to the first and second digital filters 615 and 616 (S2100).

Here, n is a frequency band position index of the analog RF signal AR ₁₂ and has values of 0, 1, 2, 3, .... The value of n may be calculated based on Equation (1) described above.

After the setting and calculation of the parameters is performed, the effect of the relative group delay between the parameters and the first path signal DR _A and the second path signal DR _B is used to determine the first and second digital filters 615, 616) coefficients are calculated (step S2200). The coefficients of the first and second digital filters 615 and 616 can be calculated using the filter function shown in Equation (10) and Equation (11) described above.

After the filter coefficients are calculated, the first and second digital filters 615 and 616 are reconstructed using the calculated filter coefficients (step S2300).

16 and 17 are views schematically showing the overall configuration of the band-pass sampling receivers 100_3 and 100_4 according to another embodiment of the present invention. 16 and 17 show the configuration when the center frequency of the complex baseband signal extracted by the complex baseband signal extractor 60 is zero.

The band-pass sampling receiver 100_3 shown in FIG. 16 is substantially the same as the band-pass sampling receiver 100_1 shown in FIG. 2 in the rest of the configuration except that the digital up / down converter 80 is not provided. The bandpass sampling receiver 100_4 shown in FIG. 17 is also substantially the same as the bandpass sampling receiver 100_2 shown in FIG. 3 except that the digital up / down converter 80 is not provided . The band-pass sampling receiver 100_3 shown in FIG. 16 is substantially the same as the band-pass sampling receiver 100_4 shown in FIG. 17 in the rest of the configuration except that it does not have a track-and-holder 40. FIG. 16 and 17, the detailed configuration of the complex baseband signal extracting unit 60 is similar to that of the complex baseband signal extracting unit 60 according to the first to sixth embodiments of the present invention shown in FIG. 4 and FIGS. 9 to 13, Band signal extracting unit 60_160_6. Therefore, the same reference numerals are assigned to the same components, and redundant description of the same components will be omitted below.

When the complex baseband signal extractor 60 generates a complex baseband signal having a center frequency of 0, the digital up / down converter (80 of FIGS. 2 and 3) for shifting the center frequency of the complex baseband signal to zero ) May not be provided in the band-pass sampling receivers 100_3 and 100_4. If the digital up / down converter 80 is not provided, the size and manufacturing cost of the band-pass sampling receivers 100_3 and 100_4 will be further reduced.

18 is a flowchart illustrating an example of a complex baseband signal extracting method according to another embodiment of the present invention. The complex baseband signal extracting method shown in FIG. 18 can be applied to all of the band-pass sampling receivers 100_3 and 100_4 according to another embodiment of the present invention including the complex baseband signal extractors 60 and 60_160_6 described above Can be applied.

The complex baseband signal extracting method shown in FIG. 18 is the same as that shown in FIG. 14 except for the fact that the extracted complex baseband signal is not subjected to up / down conversion (a configuration in which S1400 of FIG. 14 is omitted) Is substantially the same as the complex baseband signal extraction method. 2 and 3) for shifting the center frequency of the complex baseband signal to zero when the complex baseband signal extractor 60 generates a complex baseband signal having a center frequency of zero, 80) may not be provided in the band-pass sampling receivers 100_3, 100_4.

Therefore, the same reference numerals are assigned to the same components, and redundant description of the same components will be omitted below.

19 is a flowchart illustrating an example of a complex baseband signal extracting method according to another embodiment of the present invention. The complex baseband signal extracting method shown in FIG. 19 can be selectively applied to all the band-pass sampling receivers 100_1100_4 including the complex baseband signal extractor 60, 60_160_6 described in the present invention.

The complex baseband signal extracting method shown in FIG. 19 can selectively perform up / down conversion on the extracted complex baseband signal according to whether the center frequency of the extracted complex baseband signal is zero or not. The method of extracting a complex baseband signal shown in FIG. 19 includes the steps of determining whether the center frequency of the extracted complex baseband signal is 0 (step S1350), and calculating a complex baseband signal based on the discrimination result in step S1350 Baseband signal extracting method shown in Figs. 14 and 18 is substantially the same as the method of extracting complex baseband signals shown in Figs. 14 and 18 except for the operation (S1400, S1500) of selectively performing up / Therefore, the same reference numerals are assigned to the same components, and redundant description of the same components will be omitted below.

As described above, the band-pass sampling receiver 100_1100_4 of the present invention eliminates aliasing and outputs a desired complex baseband signal (even if the complex signals transited from the positive frequency band and the negative frequency band are aliased in the baseband) DR ₁ from the complex baseband signal extractor 60, 60_160_6.

According to the configuration of the complex baseband signal extracting unit 60, 60_160_6, even though a single analog-to-digital converter is used, extraction of a complex baseband signal is not affected by a specific sample rate, Or the complex signal transited from the negative frequency band can be perfectly extracted. Thus, compared to conventional bandpass sampling receivers, where the sample rate is limited to a particular type of sample rate, the sample rate can be selected more flexibly and reception is possible for all frequency bands and signal bandwidths. In addition, the hardware complexity is reduced as compared with the conventional band-pass sampling receiver, and the size and manufacturing cost of the receiver are reduced.

As described above, an embodiment of the present invention has been disclosed. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: Antenna
20: Bandpass filter (BPF)
30: Low Noise Amplifier (LNA)
40: track and holder
50: Analog-to-digital converter (ADC)
60, 60_160_6: complex baseband signal extracting unit
80: Digital up / down converter
90: Digital Signal Processor (DSP)
100_1100_4: Band-pass sampling receiver

Claims (13)

An analog-to-digital converter for converting an analog radio signal to a digital baseband signal; And
And a complex baseband signal extractor for generating a first path signal and a second path signal from the digital baseband signal and extracting a complex baseband signal using a relative sample delay difference between the first and second path signals Band-pass sampling receiver. The method according to claim 1,
Wherein the first path signal is a signal obtained by applying a sample delay and a down-sampling operation to the digital baseband signal, and the second path signal is a signal obtained by applying a down-sampling operation to the digital baseband signal. 3. The method of claim 2,
The complex baseband signal extracting unit extracts,
A first delay for sample delaying the digital baseband signal converted in the analog-to-digital converter;
A first down-sampler for down-sampling the delay result of the first delay to generate the first path signal;
A second downsampler for down-sampling the digital baseband signal converted by the analog-to-digital converter to generate the second path signal;
A first digital filter for filtering a first path signal to which the sample delay and downsampling operations are applied;
A second digital filter for filtering a second path signal to which the downsampling operation is applied; And
And an adder for adding the filtered result of the first digital filter and the filtered result of the second digital filter to output the complex baseband signal. The method of claim 3,
Wherein a relative time delay difference due to the relative sample delay difference between the first path signal and the second path signal is determined by a sampling rate of the analog-to-digital converter, a delay value of the first delay, Sampling rate of the up-sampler, and down-sampling rate of the down-sampler. The method of claim 3,
Wherein the digital filter coefficients of each of the first digital filter and the second digital filter are selected such that the carrier frequency of the analog radio signal, the frequency band position index of the analog radio signal, the sampling rate of the analog- And a down-sampling rate of the first and second down-samplers.
6. The method of claim 5,
At least one value among the sampling rate, the sample delay value (D) of the first delay and the down sampling rate (N)

Lt; / RTI >
Where n is the frequency band position index of the analog radio signal, and m is an integer. The method of claim 3,
Wherein the digital filter coefficients of each of the first digital filter and the second digital filter are selected such that the carrier frequency of the analog radio signal, the frequency band position index of the analog radio signal, the sampling rate of the analog- The first digital filter and the second digital filter are recalculated as at least one of the sample delay values of the first and second down samplers are changed, A bandpass sampling receiver, each of which is reconstructed. The method of claim 3,
The first digital filter and the second digital filter
Equation

, Equation

, Equation

, And Equation

Is determined so as to satisfy at least any one of the equations,
remind

The spectrum of the output signal of the adder,

The spectrum of the first digital filter output signal,

(F) is a spectrum of the output signal of the second digital filter, R _- (f) is a negative frequency spectrum of the digital baseband signal, R ₊ (f) is a spectrum of a positive frequency spectrum of the digital baseband signal Pass sampling receiver. The method of claim 3,
Wherein the operating speeds of the first digital filter and the second digital filter are determined by a sampling rate of the analog-to-digital converter or a downsampling rate of the first and second downsamplers. The method according to claim 1,
Wherein the first path signal is a signal to which a sample delay and a decimation operation are applied to the digital baseband signal and the second path signal is a signal to which a decimation operation is applied to the digital baseband signal. 11. The method of claim 10,
Wherein the complex baseband signal extractor comprises:
A first delay for sample delaying the digital baseband signal converted in the analog-to-digital converter;
A first decimator for pre-filtering and down-sampling the delay result of the first delay unit to generate the first path signal;
A second down-sampler for pre-filtering and down-sampling the digital baseband signal converted by the analog-to-digital converter to generate the second path signal;
A first digital filter for filtering a first path signal to which the sample delay and decimation operations are applied;
A second digital filter for filtering a second path signal to which the decimation operation is applied; And
And an adder for adding the filtered result of the first digital filter and the filtered result of the second digital filter to output the complex baseband signal. 12. The method of claim 11,
Wherein the second digital filter comprises a sample delay and a gain. 13. The method of claim 12,
Wherein the sample delay value of the sample delay is determined according to the time required for the filtering operation of the first digital filter.

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