KR101174546B1 - Pass Band Reconfigurable Digital Filter Device - Google Patents

Pass Band Reconfigurable Digital Filter Device Download PDF

Info

Publication number
KR101174546B1
KR101174546B1 KR1020100018219A KR20100018219A KR101174546B1 KR 101174546 B1 KR101174546 B1 KR 101174546B1 KR 1020100018219 A KR1020100018219 A KR 1020100018219A KR 20100018219 A KR20100018219 A KR 20100018219A KR 101174546 B1 KR101174546 B1 KR 101174546B1
Authority
KR
South Korea
Prior art keywords
image
output
unit
band
complementary
Prior art date
Application number
KR1020100018219A
Other languages
Korean (ko)
Other versions
KR20110098554A (en
Inventor
남상원
김경재
정성일
Original Assignee
한양대학교 산학협력단
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 한양대학교 산학협력단 filed Critical 한양대학교 산학협력단
Priority to KR1020100018219A priority Critical patent/KR101174546B1/en
Priority claimed from PCT/KR2011/001407 external-priority patent/WO2011105879A2/en
Publication of KR20110098554A publication Critical patent/KR20110098554A/en
Application granted granted Critical
Publication of KR101174546B1 publication Critical patent/KR101174546B1/en

Links

Images

Classifications

    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H17/00Networks using digital techniques
    • H03H17/02Frequency selective networks
    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H17/00Networks using digital techniques
    • H03H17/02Frequency selective networks
    • H03H17/0223Computation saving measures; Accelerating measures
    • H03H17/0227Measures concerning the coefficients
    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H17/00Networks using digital techniques
    • H03H17/02Frequency selective networks
    • H03H17/06Non-recursive filters
    • H03H17/0621Non-recursive filters with input-sampling frequency and output-delivery frequency which differ, e.g. extrapolation; Anti-aliasing
    • H03H17/0635Non-recursive filters with input-sampling frequency and output-delivery frequency which differ, e.g. extrapolation; Anti-aliasing characterized by the ratio between the input-sampling and output-delivery frequencies
    • H03H17/065Non-recursive filters with input-sampling frequency and output-delivery frequency which differ, e.g. extrapolation; Anti-aliasing characterized by the ratio between the input-sampling and output-delivery frequencies the ratio being integer
    • H03H17/0657Non-recursive filters with input-sampling frequency and output-delivery frequency which differ, e.g. extrapolation; Anti-aliasing characterized by the ratio between the input-sampling and output-delivery frequencies the ratio being integer where the output-delivery frequency is higher than the input sampling frequency, i.e. interpolation
    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H17/00Networks using digital techniques
    • H03H17/02Frequency selective networks
    • H03H17/06Non-recursive filters
    • H03H17/0621Non-recursive filters with input-sampling frequency and output-delivery frequency which differ, e.g. extrapolation; Anti-aliasing
    • H03H17/0635Non-recursive filters with input-sampling frequency and output-delivery frequency which differ, e.g. extrapolation; Anti-aliasing characterized by the ratio between the input-sampling and output-delivery frequencies
    • H03H17/065Non-recursive filters with input-sampling frequency and output-delivery frequency which differ, e.g. extrapolation; Anti-aliasing characterized by the ratio between the input-sampling and output-delivery frequencies the ratio being integer
    • H03H17/0664Non-recursive filters with input-sampling frequency and output-delivery frequency which differ, e.g. extrapolation; Anti-aliasing characterized by the ratio between the input-sampling and output-delivery frequencies the ratio being integer where the output-delivery frequency is lower than the input sampling frequency, i.e. decimation

Abstract

Disclosed is a digital filter device capable of reconstructing a pass band. The disclosed filter apparatus has a first output for forming a pass band corresponding to a plurality of multi images through interpolation based on a predetermined sampling constant and a pass corresponding to a plurality of complimentary images in a frequency region in which the multi image is not formed. An upsampling unit generating a second output forming a band; An image number adjustment output unit configured to adjust the number of the multi-image included in the first output of the upsampling unit and the complementary image included in the second output; By subtracting the output of the image number control output part whose number has been adjusted up to the L-th image and the output of the image number control part whose number has been adjusted up to the (L-1) th image, corresponding to each multi-image and multi-complementary image A second subtraction unit outputting a band pass signal; A register for storing a band pass signal of each of the multi-image and each of the multi-complementary images output from the second subtraction unit; And a summation unit for extracting and summing band pass signals of a multi image or a multi-complementary image corresponding to a user-specified pass band. According to the disclosed filter device, there is an advantage in that the pass band can be simply changed by simply changing a parameter.

Description

Pass Band Reconfigurable Digital Filter Device

The present invention relates to a digital filter, and more particularly, to a digital filter for passing a signal of a specific frequency band in a digital signal.

Digital filters have many advantages compared to analog filters because they can be integrated circuits and can be miniaturized, low cost, and high in reliability. In particular, as the communication speed, high speed, and the amount of communication increase, the field of application of the digital filter is increasing, and it is used in places such as the transmitting end and the receiving end of the baseband part of the mobile communication system.

Digital filters are generally divided into finite impulse response (FIR) filters and infinite impulse response (IIR) filters.

The finite impulse response filter uses the property that the impulse response will be of finite length when it is input to the filter because the finite impulse response filter does not use any feedback.

Finite impulse response filters that do not use feedback do not require a feedback loop to ensure stability. In particular, since the specification of the linear phase characteristic is satisfied, it is widely used for applications such as waveform transmission. However, when the finite impulse response filter tries to obtain the amplitude characteristic that is the same as that of the infinite impulse response filter, the order becomes larger, which causes more burden on hardware such as an adder and a multiplier.

When designing a finite impulse response filter, there are two design methods in the frequency domain and a design method in the time domain, and a window function method and a frequency sampling method are frequently used when designing in the frequency domain.

On the other hand, when designing in the time domain, the impulse response corresponds to the coefficients of the finite impulse response filter, which is simpler than the design in the frequency domain, and there are many known linear programming methods to approximate the transfer function. The optimal solution can be found.

In particular, the finite impulse response filter allows so that calculations whose finiteness of their outputs do not produce decimated outputs, or calculations with predictable values in interpolated outputs, are omitted, so called multirate. ) Is computationally efficient in applications, for example when interpolated or decimated to raise or lower the sampling rate of a signal.

The finite impulse response filter implemented in the form of hardware has a problem that it is very difficult to reconstruct the band pass characteristics when the number of taps and the filter coefficients are fixed and designed to have a specific pass band.

1 is a diagram illustrating an example of a filter for reconstructing a frequency by changing a conventional filter coefficient.

Referring to FIG. 1, a frequency reconstruction filter according to a conventional example includes a coefficient storage unit 100, a multiplexer 102, a multiplier 104, and an adder 106. The coefficient storage unit 100 of the conventional reconstruction filter stores coefficient information for a plurality of pass bands. By extracting the coefficient information according to the user's band selection and providing it to the multiplexer 102 so that the filter impulse response corresponding to the selected band can be generated, the generated filter impulse response is the input function (x [n]) The output signal y [n] is generated by filtering the input function.

Such a conventional method has a limitation in a band that can be reconstructed, and even if frequency reconstruction is performed, only the coefficients of the filter are changed, so that proper reconstruction is difficult to be achieved.

Various frequency reconstruction schemes have been proposed in addition to the above-described methods, but there are many restrictions in reconfiguring frequencies without changing hardware, and in particular, frequency reconfiguration is very complicated due to too many parameters to be changed.

The present invention provides a digital filter device capable of simply changing the pass band by changing a simple parameter.

In addition, the present invention provides a digital filter device capable of reconstructing a pass band to have various band pass characteristics without changing hardware.

In addition, the present invention provides a digital filter device that allows a user to freely select a pass band while implementing good skirt characteristics with a small number of taps.

Other aspects of the present invention will be readily apparent to those skilled in the art through the following examples.

According to an aspect of the present invention, a plurality of complimentary images are provided in a frequency domain in which the first output and pass-bands corresponding to the plurality of multi-images are formed through interpolation based on a predetermined sampling constant and the multi-images are not formed. An upsampling unit configured to generate a second output forming a passband corresponding to the upsampling unit; An image number adjustment output unit configured to adjust the number of the multi-image included in the first output of the upsampling unit and the complementary image included in the second output; By subtracting the output of the image number control output part whose number has been adjusted up to the L-th image and the output of the image number control part whose number has been adjusted up to the (L-1) th image, corresponding to each multi-image and multi-complementary image A second subtraction unit outputting a band pass signal; A register for storing a band pass signal of each of the multi-image and each of the multi-complementary images output from the second subtraction unit; There is provided a digital filter device capable of reconstructing a pass band including an adder for extracting and summing band pass signals of a multi image or a multi-complementary image corresponding to a designated pass band.

The upsampling unit includes a pass band including a first delay unit delaying an input signal based on the sampling constant to generate the first output and a filter unit filtering an output signal of the first delay unit to generate a first output. A digital filter device capable of reconstruction is provided.

The upsampling unit delays the output signal of the first delay unit based on the number of taps of the filter unit and the sampling constant to generate the second output, and the second delay unit from the output signal of the filter unit. The apparatus may further include a first subtraction unit for subtracting the output signal.

Each of the plurality of multi-image and complementary images has the same shape as the base-band multi-image.

The multi-image and multi-complementary image have a predetermined period, which corresponds to the bandwidth of the baseband multi-image.

The sampling constant (

Figure 112010013012079-pat00001
) May be set by the following equation.

Figure 112010013012079-pat00002

In the above equation

Figure 112010013012079-pat00003
Is the frequency of the passband
Figure 112010013012079-pat00004
Is the frequency of the stopband.

The image number control output unit scales by a sampling constant and applies the first sampling kernel including the multi-image number as a variable to the first output of the upsampling unit to generate an output of adjusting the number of the multi-images.

The first sampling kernel including the multi-image number as a variable may be set as in the following equation.

Figure 112010013012079-pat00005

In the above equation, L is the image number,

Figure 112010013012079-pat00006
Is the sampling constant.

The image number adjusting output unit is scaled by a sampling constant and adjusts the number of the multi-complementary images by applying a second sampling kernel including a multi-complementary image number as a variable to the second output of the up-sampling unit. Produces one output.

The second sampling kernel including the multi-complementary image number as a variable may be set as in the following equation.

Figure 112010013012079-pat00007

In the above equation, L is the multi-complementary image number

Figure 112010013012079-pat00008
Is the sampling constant.

The second delay unit in the z domain

Figure 112010013012079-pat00009
Correspondingly delays the output signal of the first delay unit.

The maximum value of the image number is set by a sampling constant, and the number from the adjusted output to the (L-1) th image until the Lth image is changed until the image number L becomes the maximum while changing the image number L. Repeated subtraction of the adjusted output.

According to another aspect of the present invention, a plurality of complimentary images in a frequency domain in which the first output and pass-band corresponding to the plurality of multi-images are formed through interpolation based on a predetermined sampling constant and the multi-image is not formed. An upsampling unit configured to generate a second output forming a passband corresponding to the upsampling unit; An image number adjustment output unit configured to adjust the number of the multi-image included in the first output of the upsampling unit and the complementary image included in the second output; By subtracting the output of the image number control output part whose number has been adjusted up to the L-th image and the output of the image number control part whose number has been adjusted up to the (L-1) th image, corresponding to each multi-image and multi-complementary image A second subtraction unit outputting a band pass signal; And a register for storing a band pass signal of each of the multi-image and each of the multi-complementary images output from the second subtraction unit, and outputting a band-pass signal of the multi-image or multi-complementary image corresponding to a specified pass band. Provided is a digital filter device capable of reconstructing a pass band including a.

According to another aspect of the present invention, a plurality of compliments in the first output to form a pass band corresponding to the plurality of multi-images through interpolation based on a predetermined sampling constant and in the frequency region where the multi-image is not formed An upsampling step (a) of generating a second output forming a passband corresponding to the image; (B) an image number adjustment output step of controlling and outputting the number of the multi-image included in the first output and the complementary image included in the second output; By subtracting the output of the step (b) in which the number is adjusted to the L-th image and the output of the step (b) in which the number is adjusted to the (L-1) th image, each multi-image and multi-complementary image is subtracted. A subtraction step (c) of outputting a corresponding band pass signal; Storing and storing band pass signals of each multi-image and each multi-complementary image output in step (c), and outputting a band pass signal of a multi-image or a multi-complementary image corresponding to a predetermined pass band. Provided is a digital filtering method capable of reconstructing a pass band including the step (d).

According to the embodiment of the present invention, there is an advantage in that the pass band can be simply changed by simply changing the parameter.

In addition, according to an embodiment of the present invention, it is possible to reconfigure the pass band to have various band pass characteristics without changing hardware, and the user can freely select the pass band while implementing a good skirt characteristic with a small number of taps. have.

1 is a diagram showing an example of a filter for reconstructing a frequency by changing a conventional filter coefficient.
2 is a block diagram showing a module configuration of a digital filter device capable of reconstructing a pass band according to an embodiment of the present invention.
3 is a diagram illustrating an internal module configuration of a general filter.
4 illustrates a conceptual module of a filter for performing upsampling by a delay unit and a filter unit.
FIG. 5 is a graph showing an output of an impulse response of only the filter unit when the impulse function is input and an impulse response when the first delay unit and the filter unit operate integrally. FIG.
6 shows an example of a multi-image generated by the first output of the present invention and a multi-complementary image generated by the second output of the present invention.
FIG. 7 illustrates an example in which an image number is assigned to a multi-image of a first output of an upsampling unit according to an embodiment of the present invention. FIG.
8 illustrates an example in which an image number is assigned to a multi-complementary image of a second output of an upsampling unit according to an embodiment of the present invention.
9 illustrates a signal storage structure of a register according to an embodiment of the present invention.
FIG. 10 illustrates an example in which a filter response in which filtering is performed for multiple bands is configured according to an embodiment of the present invention. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, the same or corresponding components will be given the same reference numerals and redundant description thereof will be omitted.

2 is a block diagram showing a module configuration of a digital filter device capable of reconstructing a pass band according to an embodiment of the present invention.

Referring to FIG. 2, a digital filter device capable of reconstructing a pass band according to an embodiment of the present invention includes a first delay unit 200, a filter unit 202, a second delay unit 204, and a first subtraction unit. An upsampling unit 220 including an 206, an image number control output unit 208, a second subtraction unit 210, a register 212, and an adder 214 may be included.

The upsampling unit 220 performs upsampling on the filter response of the filter unit 202. The filter unit 202 included in the upsampling unit 220 may be implemented as a general filter chip, and has a fixed number of taps and a filter response.

The skirt characteristic of the filter portion 202 is determined by the number of taps of the filter. The higher the number of tabs of the filter, the better the skirt characteristic of the filter. However, in order to secure a large number of taps, the cost of the filter chip increases, and thus, the skirt characteristics of the filter are in a trade-off relationship with the cost of the filter.

The upsampling unit 220 performs upsampling to have a better skirt characteristic than the number of taps of the filter unit 202. Such upsampling may be implemented by the first delay unit 200.

In addition, the filter response of the filter unit 202 is changed to have a plurality of pass bands as well as a base band pass band uniquely set in the filter unit 202 according to the upsampling in the upsampling unit 220.

The upsampling unit 220 outputs two signals, a first output and a second output. The upsampling unit 220 first describes the first output and then describes the second output. The first output is output through the first delay unit 200 and the filter unit 202.

The first delay unit 200 delays the input signal in correspondence with the sampling constant? Set for upsampling the input signal. Delaying the input signal corresponding to the sampling constant () in the first delay unit has the same effect as inserting 0 corresponding to the sampling constant in the middle of the input signal to perform interpolation.

Meanwhile, sampling constant

Figure 112010013012079-pat00010
In setting, we can find the optimal sampling constant to have the optimal calculation amount. Equation 1 below is an example for obtaining an optimal sampling constant.
Figure 112010013012079-pat00011
Is the frequency of the passband
Figure 112010013012079-pat00012
Is the frequency of the stopband. The integer closest to the sampling constant obtained at this time is
Figure 112010013012079-pat00013
Determining and applying it can give the greatest efficiency in overall operation.

Figure 112010013012079-pat00014

Of course sampling constant

Figure 112010013012079-pat00015
May be set to other values to have the desired skirt characteristics without following the optimal equation above.

The filter unit 202 performs filtering on the output signal of the first delay unit 200. The filter unit 102 includes a plurality of delayers and an adder like a general filter chip to perform a filtering operation on an input signal.

As described above, delaying an input signal corresponding to a sampling constant and performing filtering on the same may result in substantially the same result as performing interpolation, wherein the upsampled filter response h up [n] May be expressed as Equation 2 below.

Figure 112010013012079-pat00016

FIG. 3 is a diagram illustrating an internal module configuration of a general filter, and FIG. 4 is a diagram illustrating a conceptual module of a filter performing upsampling by a delay unit and a filter unit.

Referring to FIG. 3, a general filter includes a plurality of delay units z −1 and a plurality of filter coefficients h0, h1, h2,...

Meanwhile, sampling constant

Figure 112010013012079-pat00017
In the present invention, which performs upsampling by inserting a zero corresponding to, the filter response is substantially operated as shown in Equation 2 by delaying corresponding to.

When such an upsampling method is used, it is possible to ensure better skirt characteristics compared to the number of taps of the filter used in the filter portion. For example, even if the number of taps of the filter is fixed to N, according to the present invention,

Figure 112010013012079-pat00018
The same skirt characteristics as in the case where N or more tabs are used can be ensured.

FIG. 5 is a graph illustrating an output of an impulse response of only the filter unit when the impulse function is input and an impulse response when the first delay unit and the filter unit operate integrally.

In FIG. 5, the graph of (a) is an impulse response of the filter unit only, and the graph of (b) is an impulse response when the first delay unit 200 and the filter unit 202 of the present invention operate together. It is a graph.

As shown in Figure 5, when the upsampling according to the present invention it can be seen that the skirt characteristics of the filter is significantly improved compared to the case of using only the filter unit by a general filter chip. In this case, the skirt characteristic is a sampling constant

Figure 112010013012079-pat00019
Improved in proportion to

Meanwhile, referring to FIG. 5, when upsampling according to the present invention is performed, it can be seen that a passband is formed in a plurality of bands as well as a baseband, which is an additional result of upsampling. In this embodiment, each of a plurality of pass bands formed in the frequency domain by upsampling according to the present invention will be referred to as an "image". Such multi-images occur additionally when upsampling as in the present invention is performed.

In other words, when upsampling according to the present invention is performed, a plurality of multi-images are generated in addition to the baseband. After all, when the input is an impulse function, the first output improves the skirt characteristic of the filter part well, but forms a plurality of pass bands in not only the base band but also other bands.

The multiple images formed form the same shape as the baseband image. For example, if a baseband image has a bandwidth of W, a skirt property of C, and a size of A, a plurality of formed multi-images also have the same property of having a bandwidth of W, a skirt property of C, and a size of A.

In addition, a plurality of multi-images generated by upsampling based on the baseband image have a certain period, where the period is related to the bandwidth of the baseband image.

For example, when a baseband image has a bandwidth of 2W from -W to W, many multi-images generated by upsampling are repeatedly formed in the same form as the baseband image with a period of 2W. Will be.

Thus, when there is a baseband image with a bandwidth of 2W from -W to W, upsampling produces a second multi-image in the 3W to 5W band and forms a third multi-image in the 7W to 9W band. . In this case, the number of formed multi-images may vary according to a sampling constant. As such, a plurality of multi-images generated through upsampling may be used to reconstruct a passband to a passband desired by a user.

In the above, the principle of the first output in which a pass band corresponding to a plurality of multi-images is formed by upsampling has been described. Hereinafter, the second output will be described.

The multiple images formed by the first output are formed discretely with a predetermined period. If the passband desired by the user is a frequency domain in which the multi-image is not formed, the multi-image alone cannot cover all the passband desired by the user. Therefore, it is necessary to generate images even in a frequency region where no multi-image is formed, and the second output is an output in which a plurality of images are formed in the frequency region where the multi-image is not formed. In the present embodiment, a plurality of images formed in a frequency region in which the multi-image is not formed at the second output will be referred to as a multi-complementary image.

6 is a diagram showing an example of a multi-image generated by the first output of the present invention and a multi-complementary image generated by the second output of the present invention.

Referring to FIG. 6, the multi-image generated by the first output and the multi-complementary image generated by the second output are formed in opposite frequency regions.

Multi-complementary images also have the same shape as baseband images of multi-images. That is, it has the same bandwidth, skirt characteristics, and size as the baseband image of the multi-image.

In addition, the plurality of multi-complementary images also have a certain period, where the period corresponds to the bandwidth of each image.

The second output is output through the first delay unit 200, the filter unit 202, the second delay unit 204, and the first subtraction unit 206.

The second delay unit 204 is in the z domain

Figure 112010013012079-pat00020
Correspondingly delays the output signal of the first delay unit 200. Here, N means the number of taps of the filter unit 202. The output signal of the second delay unit 204 is input to the first subtraction unit 206, and the output signal of the filter unit 202 which is the first output is also input to the first subtraction unit 206.

The first subtraction unit 206 subtracts the output signal of the second delay unit 204 from the output signal of the filter unit 202. The output signal of the first subtraction unit 206 is a second output signal and the second output corresponds to a plurality of multi-complementary images as shown in FIG. 6 to form a pass band.

The first and second outputs output from the upsampling unit 220 are input to the image number adjustment output unit 208. The image number adjustment output unit 208 adjusts and outputs the number of the plurality of multi-images and the plurality of complimentary images included in the first and second outputs.

For example, when four multi-images are included in the first output, the image number adjustment output unit 208 provides an output in which the number of the multi-images is adjusted from one to four.

An image number may be assigned to each of the multi-images of the first output, and FIG. 7 is a diagram illustrating an example in which an image number is assigned to the multi-image of the first output of the upsampling unit according to an embodiment of the present invention. FIG. 1 is a diagram illustrating an example in which an image number is assigned to a multi-complementary image of a second output of an upsampling unit according to an embodiment of the present invention.

Referring to FIG. 7, image numbers L of 0, 1, 2, and 3 are assigned to each of the multi-images.

The image number adjustment output unit 208 provides the second subtraction unit 210 with an output in which the number of images is adjusted up to the L-th image and an output in which the number is adjusted up to the (L-1) th image. For example, the second subtraction unit 210 may provide the second subtraction unit 210 with an output provided with multiple images up to image number 2 (three multi images) and an output with multiple images up to image number 1 (two multi images). This output operation is repeated until L reaches its maximum value.

That is, when L = 1 is set, the output when L is 1 and 0 is provided primarily, and when L = 2, the output when L is 2 and 1 is provided as secondary, and L is at the maximum value. It is repeatedly provided until this is done.

The response for generating the multi-image up to the image number L in the image number adjustment output unit 208 may be set as in Equation 3 below.

Figure 112010013012079-pat00021

In Equation 3 above,

Figure 112010013012079-pat00022
Is the sampling kernel and h [k] is the first output. That is, the image number control output unit 208 is an impulse response of the first output and the image number control output unit.
Figure 112010013012079-pat00023
It is possible to generate a desired multi-image up to a desired image number L through a convolution operation with. As seen from Equation 3 above, the sampling kernel is a sampling constant.
Figure 112010013012079-pat00024
Is scaled by.

Various functions may be applied as the sampling kernel. However, when the Sinc function is applied, the sampling kernel may be expressed as Equation 4 below.

Figure 112010013012079-pat00025

In addition, various functions may be applied to the sampling kernel as well as the Sinc function as the sampling kernel, and an example thereof is given by Equation 5 below.

Figure 112010013012079-pat00026

Figure 112010013012079-pat00027

Figure 112010013012079-pat00028

In Equation 5 above, the first equation is a raised-cosine, where R is a roll-off constant and is a criterion for determining the bandwidth of the filter. In Equation 5 above, the second equation is Kaiser, and the third equation is Dolph-Chebychev. This adaptive window function has the advantage that the passband has a flat characteristic, so it does not affect the specification of the final filter passband designed by applying it.

In the above, the operation of outputting the image number adjustment output unit 208 by adjusting the number of the multi-images for the first output of the upsampling unit 220 has been described. The image number adjustment output unit 208 adjusts and outputs the number of multi-complementary images in the same manner with respect to the multi-complementary image of the second output.

That is, the image number adjustment output unit 208 outputs an image in which the number of images is adjusted up to the L-th multi-complementary image for the second output and an output in which the number is adjusted to the (L-1) -th multi-complementary image. Is provided to the second subtraction unit 210. For example, the second subtraction unit 210 may provide the second subtraction unit 210 with an output provided with multiple images up to image number 2 (three multi images) and an output with multiple images up to image number 1 (two multi images). This output operation is repeated until L reaches its maximum value.

The response for adjusting and outputting the number of multi-complementary images in the image number adjustment output unit 208 is shown in Equation 6 below.

Figure 112010013012079-pat00029
An example of is as shown in Equation 7 below.

Figure 112010013012079-pat00030

Figure 112010013012079-pat00031

In Equation 6 above,

Figure 112010013012079-pat00032
Denotes a filter response for generating a complementary image.

As confirmed from Equations 6 and 7 above, the variable applied to the sampling kernel is changed from (2L + 1) to 2L. That is, there is a slight difference between the sampling kernel applied to adjust the number of multi-images of the first output and the sampling kernel applied to adjust the number of multi-complementary images of the second output.

In summary, the image number adjusting output unit 208 repeatedly provides the outputs up to the L-th image and the outputs up to the (L-1) th image until L reaches the maximum value for the multi-image of the first output. In the same manner, the number of images is adjusted to provide a multi-complementary image of the second output.

The second subtraction unit 210 outputs a band pass signal corresponding to each of the individual multi-image and the individual multi-complementary image by using the signal output from the image number control output unit.

For example, in the multi-image of the first output, the band pass signal corresponding to the image number 2 is adjusted so that the multi-image is output only to the image number 1 so that the multi-image is output to the image number 2 only. The output can be obtained by subtracting the output from the second subtraction unit.

The second subtraction unit 210 outputs a band pass signal corresponding to each of the multi-image and the multi-complementary image through a subtraction operation in the manner described above.

The register 212 stores a band pass signal corresponding to each of the multi-image and the multi-complementary image output from the second subtractor.

9 illustrates a signal storage structure of a register according to an embodiment of the present invention.

Referring to FIG. 9, a band pass signal corresponding to each multi-image and each multi-complementary image is stored.

The adder 214 sums and outputs signals corresponding to a pass band set by a user among the signals stored in the register.

For example, when the user sets a band corresponding to a multi-image of L = 2 and a multi-complementary image of L = 1 as a pass band, the adder 214 corresponds to the multi-image number 2 in the register. The stored signal and the signal stored in the register corresponding to multi-complementary image number 1 are summed to provide the final output.

As such, a method of setting a pass band by designating an image number corresponding to a required band may be usefully applied when implementing a multi-band filter.

FIG. 10 is a diagram illustrating an example of configuring a filter response for filtering in multiple bands according to an embodiment of the present invention.

In FIG. 10, (a) is a first output of an upsampling unit composed of multiple images when the input function is an impulse function, and (b) is a second output of an upsampling unit composed of a multi-complementary image when the input function is an impulse function. .

At this time, when the user selects a band corresponding to the multi-image number 3 and the complimentary image number 1, the adder 212 is the output of the multi-image number 3 stored in the register and the multi-complementary image number 0 By multiplying the outputs, a multiband filter such as (c) can be implemented.

As described above, the present invention enables reconfiguration of various pass bands by designating a pass band desired by a user, that is, a multi image or a multi-complementary image number. That is, the user can reconfigure and use the filter used as the low pass filter as a band pass filter or a multi band band pass filter by changing the L value, and does not require a separate hardware change or complicated operation.

In addition, it will be understood by those skilled in the art that the bandwidth of each multi-image or complementary image can be adjusted by adjusting the sampling constant so that a free pass band reconstruction is possible.

 Although the above has been described with reference to embodiments of the present invention, those skilled in the art may variously modify the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. And can be changed.

Claims (14)

  1. Interpolating based on a predetermined sampling constant to form a pass band corresponding to a plurality of complimentary images in a frequency domain in which the first output forms a pass band corresponding to a plurality of multi images and a frequency region in which the multi image is not formed. An upsampling unit generating a second output;
    An image number adjustment output unit configured to adjust the number of the multi-image included in the first output of the upsampling unit and the complementary image included in the second output;
    By subtracting the output of the image number control output part whose number has been adjusted up to the L-th image and the output of the image number control part whose number has been adjusted up to the (L-1) th image, corresponding to each multi-image and multi-complementary image A second subtraction unit outputting a band pass signal;
    A register for storing a band pass signal of each of the multi-image and each of the multi-complementary images output from the second subtraction unit;
    And a summation unit for extracting and summing band pass signals of a multi image or a multi-complementary image corresponding to a designated pass band from the register.
  2. The method of claim 1,
    The upsampling unit includes a first delay unit for delaying an input signal based on the sampling constant to generate the first output, and a filter unit for filtering the output signal of the first delay unit to generate a first output. A digital filter device capable of reconstructing a pass band.
  3. The method of claim 2,
    The upsampling unit delays the output signal of the first delay unit based on the number of taps of the filter unit and the sampling constant to generate the second output, and the second delay unit from the output signal of the filter unit. And a first subtraction unit for subtracting an output signal.
  4. The method of claim 1,
    And the plurality of multi-images and the complementary images each have the same shape as a base-band multi-image.
  5. The method of claim 4, wherein
    The multi-image and the multi-complementary image has a predetermined period, the predetermined period corresponding to the bandwidth of the multi-image of the baseband, the digital band passband reconfigurable device.
  6. The method of claim 1,
    The sampling constant (
    Figure 112010013012079-pat00033
    ) Is a digital filter device capable of reconstructing a pass band, characterized in that set by the following equation.
    Figure 112010013012079-pat00034

    In the above equation
    Figure 112010013012079-pat00035
    Is the frequency of the passband
    Figure 112010013012079-pat00036
    Is the frequency of the stopband.
  7. The method of claim 1,
    The image number control output unit scales by a sampling constant and generates an output of adjusting the number of the multi-images by applying a first sampling kernel including a multi-image number as a variable to the first output of the upsampling unit. A digital filter device capable of reconstructing a pass band.
  8. The method of claim 7, wherein
    And a first sampling kernel including the multi-image number as a variable is set as in the following equation.
    Figure 112010013012079-pat00037

    In the above equation, L is the image number,
    Figure 112010013012079-pat00038
    Is the sampling constant.
  9. The method of claim 1,
    The image number adjusting output unit is scaled by a sampling constant and adjusts the number of the multi-complementary images by applying a second sampling kernel including a multi-complementary image number as a variable to the second output of the up-sampling unit. A reconfigurable digital filter device, characterized in that for generating one output.
  10. 10. The method of claim 9,
    And a second sampling kernel including the multi-complementary image number as a variable is set as in the following equation.
    Figure 112010013012079-pat00039

    In the above equation, L is the multi-complementary image number
    Figure 112010013012079-pat00040
    Is the sampling constant.
  11. The method of claim 3,
    The second delay unit in the z domain
    Figure 112010013012079-pat00041
    And reconstructing the output signal of the first delay unit in response to the delay.
  12. The method of claim 1,
    The maximum value of the image number is set by a sampling constant, and the number from the adjusted output to the (L-1) th image until the Lth image is changed until the image number L becomes the maximum while changing the image number L. A digital filter device capable of reconstructing a pass band, characterized by repeatedly performing a subtraction of the adjusted output.
  13. Interpolating based on a predetermined sampling constant to form a pass band corresponding to a plurality of complimentary images in a frequency domain in which the first output forms a pass band corresponding to a plurality of multi images and a frequency region in which the multi image is not formed. An upsampling unit generating a second output;
    An image number adjustment output unit configured to adjust the number of the multi-image included in the first output of the upsampling unit and the complementary image included in the second output;
    By subtracting the output of the image number control output part whose number has been adjusted up to the L-th image and the output of the image number control part whose number has been adjusted up to the (L-1) th image, corresponding to each multi-image and multi-complementary image A second subtraction unit outputting a band pass signal; And
    A register for storing a band pass signal of each of the multi-image and each of the multi-complementary images output from the second subtractor and outputting a band-pass signal of the multi-image or multi-complementary image corresponding to a specified pass-band Digital filter device capable of reconstructing the pass band comprising a.
  14. Interpolating based on a predetermined sampling constant to form a pass band corresponding to a plurality of complimentary images in a frequency domain in which the first output forms a pass band corresponding to a plurality of multi images and a frequency region in which the multi image is not formed. An upsampling step (a) of generating a second output;
    (B) an image number adjustment output step of controlling and outputting the number of the multi-image included in the first output and the complementary image included in the second output;
    By subtracting the output of the step (b) in which the number is adjusted to the L-th image and the output of the step (b) in which the number is adjusted to the (L-1) th image, each multi-image and multi-complementary image A subtraction step (c) of outputting a corresponding band pass signal;
    Storing and storing band pass signals of each multi-image and each multi-complementary image output in step (c), and outputting a band pass signal of a multi-image or a multi-complementary image corresponding to a predetermined pass band. And (d) performing a reconstruction of a pass band.
KR1020100018219A 2010-02-26 2010-02-26 Pass Band Reconfigurable Digital Filter Device KR101174546B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020100018219A KR101174546B1 (en) 2010-02-26 2010-02-26 Pass Band Reconfigurable Digital Filter Device

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
KR1020100018219A KR101174546B1 (en) 2010-02-26 2010-02-26 Pass Band Reconfigurable Digital Filter Device
PCT/KR2011/001407 WO2011105879A2 (en) 2010-02-26 2011-02-28 Frequency reconfigurable digital filter and equalizer using the same
US13/580,133 US9099989B2 (en) 2010-02-26 2011-02-28 Frequency reconfigurable digital filter and equalizer using the same
PCT/KR2011/001408 WO2011105880A2 (en) 2010-02-26 2011-02-28 Digital filter having improved attenuation characteristics
CN2011800111988A CN102812637A (en) 2010-02-26 2011-02-28 Frequency reconfigurable digital filter and equalizer using the same
EP11747769.5A EP2540000B1 (en) 2010-02-26 2011-02-28 Frequency reconfigurable digital filter and equalizer using the same
JP2012554949A JP5882917B2 (en) 2010-02-26 2011-02-28 Digital filter capable of frequency reconstruction, filtering method, equalizer using the same, and design method thereof
US13/581,292 US9225315B2 (en) 2010-02-26 2011-02-28 Digital filter having improved attenuation characteristics

Publications (2)

Publication Number Publication Date
KR20110098554A KR20110098554A (en) 2011-09-01
KR101174546B1 true KR101174546B1 (en) 2012-08-16

Family

ID=44952083

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020100018219A KR101174546B1 (en) 2010-02-26 2010-02-26 Pass Band Reconfigurable Digital Filter Device

Country Status (1)

Country Link
KR (1) KR101174546B1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102881688B (en) 2012-09-19 2015-04-15 北京京东方光电科技有限公司 Array substrate, display panel and array substrate manufacturing method
KR101920719B1 (en) 2012-11-19 2019-02-13 삼성전자주식회사 Logic device, digital filter including the same, and method to control the same

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008148260A (en) 2006-12-13 2008-06-26 Rohm Co Ltd Digital filter, filtering method and digital audio processing circuit using them, and electronic device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008148260A (en) 2006-12-13 2008-06-26 Rohm Co Ltd Digital filter, filtering method and digital audio processing circuit using them, and electronic device

Also Published As

Publication number Publication date
KR20110098554A (en) 2011-09-01

Similar Documents

Publication Publication Date Title
US20170134854A1 (en) Multi-rate filter system
EP3226415B1 (en) Low delay modulated filter bank
EP1297626B1 (en) Sample rate conversion method and apparatus
Brennan et al. A flexible filterbank structure for extensive signal manipulations in digital hearing aids
US20120185524A1 (en) Multi-Rate Implementation Without High-Pass Filter
JP2005006274A (en) Effective and flexibly oversampling type filter bank having substantially complete reconfiguration constraint
US7236110B2 (en) Sample rate converter for reducing the sampling frequency of a signal by a fractional number
Renfors et al. Analysis and design of efficient and flexible fast-convolution based multirate filter banks
EP2157695A2 (en) Sample rate converter with rational numerator or denominator
US6643675B2 (en) Filtering method and filter
CN1819457B (en) Sample rate converter
Milic Multirate Filtering for Digital Signal Processing: MATLAB Applications: MATLAB Applications
US7620673B2 (en) Complimentary discrete fourier transform processor
US7395290B2 (en) Digital filter and method thereof using frequency translations
Crochiere et al. Interpolation and decimation of digital signals—A tutorial review
JP4235557B2 (en) Multirate digital transceiver
US8488656B2 (en) Oversampled synthesizer systems and methods
KR102175019B1 (en) Cancellation pulse crest factor reduction
KR100799406B1 (en) Digital sampling rate converter for compensating signal droop in band
Chen et al. Non-maximally decimated analysis/synthesis filter banks: Applications in wideband digital filtering
JPH0846484A (en) Digital-digital-sampling rate converter
US20020156820A1 (en) Frequency converter
JP5638787B2 (en) Subband signal processing
Hentschel et al. The digital front-end: Bridge between RF and baseband processing
US7117235B2 (en) Digital decimation filter having finite impulse response (FIR) decimation stages

Legal Events

Date Code Title Description
A201 Request for examination
E701 Decision to grant or registration of patent right
GRNT Written decision to grant
FPAY Annual fee payment

Payment date: 20160705

Year of fee payment: 5

FPAY Annual fee payment

Payment date: 20180702

Year of fee payment: 7

FPAY Annual fee payment

Payment date: 20190624

Year of fee payment: 8