Non-Maximal Decimated Filter Bank (NMDFB) and
Its Application in Wideband Signal Processing
Dec 6, 2012
Xiaofei Chen
4
Non-Maximal Decimated Filter Bank, Contโd
๐ (๐ )= 1๐ท๐ฎ1ร๐
๐ ( ๐ )๐๐ ร๐ (๐ )โ๐ ร๐ท ( ๐ ) ๐ฟ ๐ทร1 ( ๐ )= 1๐ท๐ป๐
1ร๐ท ( ๐ ) ๐ฟ๐ทร 1 ( ๐ )
๐ป๐1ร๐ท (๐ )โ๐ฎ1ร๐
๐ (๐ )๐๐ร๐ ( ๐ )โ๐ ร๐ท (๐ )= [๐ ๐ ๐ (๐ )๐ป ๐ด
๐ (๐ ) ]๐ (๐ )= 1
๐ท๐ ๐
๐ (๐ )๐ (๐ )+ 1๐ท๐ป ๐ด
๐ (๐ ) ๐ฟ (๐ )
5
Non-Maximal Decimated Filter Bank, Contโd
๐ป (๐๐ ๐ท๐ )๐บ (๐ )=0 , โ๐=1 ,โฆ,๐ทโ1
โ๐=0
๐โ1
๐ป (๐๐๐๐ )๐บ (๐๐๐
๐ )=๐โ๐๐ท
Aliasing Cancellation Condition:
Perfect Reconstruction Condition:
8
Filtering with NMDFB
NMDFB filter:
๐ ๐ (๐ )=๐ ๐ ๐ (๐ ) ๐ (๐ )+๐ป ๐ด
๐ (๐ ) ๐ฟ (๐ )โ ๐ ๐ ๐ (๐ ) ๐ (๐ )
Time Domain filter:
๐ ๐ก (๐ )=๐ (๐ )๐โ๐๐ท ๐ (๐ )
9
Filtering with NMDFB, Contโd
Error between two filtering models:
Error Transfer Function:
โฐ (๐ )=๐ ๐ก (๐ )โ๐ ๐ (๐ )= [๐ ๐ ๐ (๐ )๐๐๐โ๐ (๐ ) ] ๐ (๐ )๐โ๐๐
10
Filtering with NMDFB, Contโd
Piecewise Constant Approximation:
Linear Interpolation
~h๐๐๐ (๐)= 1๐๐๐ผ๐๐ถ2( 1๐ ๐) , ๐๐๐ โ๐๐โค๐โค๐๐
~๐ป๐๐๐ (๐โ๐๐)={1โ|๐โ๐๐
2๐ /๐ |,๐โ[๐๐โ2๐๐,๐๐+ 2๐
๐]
0 , h๐๐ก ๐๐๐ค๐๐ ๐
11
Filtering with NMDFB, Contโd
Piecewise Constant Approximation Performance:
|๐ โฐ ,๐๐ ๐ (๐ )|โค |๏ฟฝฬ๏ฟฝ๐ ๐ (๐ )|
๐โ [๐๐โ๐๐,๐๐ยฑ
๐๐ ]Max
โ๐๐
=๐ตโฐ ,๐๐ ๐
|๐ โฐ ,๐๐ผ๐ (๐ )|โค |๏ฟฝฬ๏ฟฝ๐ผ๐ (๐ )|
๐โ [๐๐โ๐๐,๐๐ยฑ
๐๐ ]Max
โ๐๐
=๐ตโฐ ,๐๐ผ๐
|๐ โฐ ,๐ (๐ )|โคโ (๐ตโฐ ,๐๐ ๐ )2+(๐ตโฐ ,๐
๐ผ๐ )2โ๐ตโฐ ,๐
๐๐โค๐๐ก๐๐( ๐ตโฐ ,๐
โ (๐พ๐ ,๐ )2โ (๐ตโฐ ,๐ )2 ) , ๐๐๐ ๐พ๐ ,๐>๐ตโฐ ,๐
๐พ๐ ,๐โ |๐ (๐ )|๐โ[๐๐โ
๐๐,๐๐ ยฑ
๐๐ ]๐๐๐
12
Filtering with NMDFB, Contโd
Linear Interpolation Approximation Performance:
|๐ โฐ ,๐๐ ๐ (๐ )|โค |๏ฟฝฬ๏ฟฝ๐ ๐ (๐ )|๐โ [๐๐ ,๐๐+1]
Maxโ12 ( ๐๐ )
2
=๐ตโฐ ,๐๐ ๐
|๐ โฐ ,๐๐ผ๐ (๐ )|โค |๏ฟฝฬ๏ฟฝ๐ผ๐ (๐ )|๐โ [๐๐ ,๐๐+1]
Maxโ12 ( ๐๐ )
2
=๐ตโฐ ,๐๐ผ๐
|๐ โฐ ,๐ (๐ )|โคโ (๐ตโฐ ,๐๐ ๐ )2+(๐ตโฐ ,๐
๐ผ๐ )2โ๐ตโฐ ,๐
๐๐โค๐๐ก๐๐( ๐ตโฐ ,๐
โ (๐พ๐ ,๐ )2โ (๐ตโฐ ,๐ )2 ) , ๐๐๐ ๐พ๐ ,๐>๐ตโฐ ,๐
๐พ๐ ,๐โ |๐ (๐ )|๐โ [๐๐,๐๐+1 ]๐๐๐
13
NMDFB Design Example
M = 64, D = 32Rectangular
02
M
2
M
4
M
4
M
S ynthe s is F ilte rG (Z)
M o d u la ted Im a g eo f H (Z)
02
M
2
M
4
M
4
M
S ynthe s is F ilte rG (Z )
M o d u la ted Im a g eo f H (Z)
0 4
M
4
M
S ynthe s is F ilte rG (Z )
M o d u la ted Im a g eo f H (Z)
8
M
8
M
M = 64, D = 32Triangular
M = 64, D = 16Triangular
14
NMDFB Simulation
M = 64, D = 32 RectangularImpulse Response and Filter Spectra
690 700 710 720 730 740 750 760 770 7800
0.5
1
1.5
Analysis / Synthesis Impulse Response
Samples / n
Am
plit
ud
e
200 400 600 800 1000 1200-2
-1
0
1
2x 10
-5
X: 1121Y: -1.343e-005
Details of the Impulse Response Artifacts
Samples / n
Am
plit
ud
e
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3
-100
-80
-60
-40
-20
0
Frequency (fs = 64)
Log
Mag
(dB
)
Analysis Filter Spectra
H
0()
H1()
-4 -3 -2 -1 0 1 2 3 4
-100
-50
0
Frequency (fs = 64)
Log
Mag
(dB
)
Analysis Filter and Synthesis Filter Spectra
H
0()
G0()
H2()
H62
()
15
NMDFB Simulation, Contโd
M = 64, D = 16 TriangularImpulse Response and Filter Spectra
450 460 470 480 490 500 510 520 530 5400
0.5
1
1.5
Analysis / Synthesis Impulse Response
Samples / n
Am
plit
ud
e
0 200 400 600 800 1000-2
-1
0
1
2x 10
-5
X: 626Y: -4.975e-006
Details of the Impulse Response Artifacts
Samples / n
Am
plit
ud
e
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3
-100
-50
0
Frequency (fs = 64)
Log
Mag
(dB)
Analysis Filter Spectra
H
0()
H1()
-8 -6 -4 -2 0 2 4 6 8
-100
-50
0
Frequency (fs = 64)
Log
Mag
(dB)
Analysis Filter and Synthesis Filter Spectra
H
0()
G0()
H4()
H60
()
16
NMDFB Simulation, Contโd
M = 64, D = 16 TriangularImpulse Response and Filter Spectra
450 460 470 480 490 500 510 520 530 5400
0.5
1
1.5
Analysis / Synthesis Impulse Response
Samples / n
Am
plit
ud
e
0 200 400 600 800 1000-2
-1
0
1
2x 10
-5
X: 626Y: -4.975e-006
Details of the Impulse Response Artifacts
Samples / n
Am
plit
ud
e
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3
-100
-50
0
Frequency (fs = 64)
Log
Mag
(dB)
Analysis Filter Spectra
H
0()
H1()
-8 -6 -4 -2 0 2 4 6 8
-100
-50
0
Frequency (fs = 64)
Log
Mag
(dB)
Analysis Filter and Synthesis Filter Spectra
H
0()
G0()
H4()
H60
()
17
NMDFB Filtering Simulation 1
M = 64, D = 32 Rectangular / M = 256 Triangular Linear Phase Filtering
0 0.1 0.2 0.3 0.4 0.5
-100
-50
0
Normalized Frequency
Log
Mag
(dB
)
Magnitude Responses of Original Filter and Synthesized Filter
OriSyn
0 0.1 0.2 0.3 0.4 0.5
-100
-50
0
Normalized Frequency
Log
Mag
(dB
)
Magnitude Error between Original Filter and Synthesized Filter
Mag ErrErr Bound
0 0.1 0.2 0.3 0.4 0.5-1
0
1x 10
-4 Phase Error between Original Filter and Synthesized Filter
Normalized Frequency
Nor
mal
ized
Ang
le
Phase ErrErr Bound
0 0.1 0.2 0.3 0.4 0.5
-100
-50
0
Normalized Frequency
Log
Mag
(dB
)
Magnitude Responses of Original Filter and Synthesized Filter
OriSyn
0 0.1 0.2 0.3 0.4 0.5
-100
-50
Normalized Frequency
Log
Mag
(dB
)
Magnitude Error between Original Filter and Synthesized Filter
Mag ErrMinimax BoundSub-Opt Bound
0 0.1 0.2 0.3 0.4 0.5
-101
x 10-5 Phase Error between Original Filter and Synthesized Filter
Normalized Frequency
Nor
mal
ized
Ang
le
Phase ErrorMinimax BoundSub-Opt Bound
18
NMDFB Filtering Simulation 2
M = 64, D = 32 Rectangular / TriangularNon Linear Phase Filtering
-0.5 0 0.5
-20
0
20
Normalized Frequency
Log
Ma
g (
dB
) Magnitude Responses of Original Filter and Synthesized Filter
OriSyn
-0.5 0 0.5
-20
0
20
Normalized Frequency
Log
Ma
g (
dB
) Magnitude Error between Original Filter and Synthesized Filter
Mag ErrErr Bound
-0.5 0 0.5-0.5
0
0.5Phase Error between Original Filter and Synthesized Filter
Normalized Frequency
Norm
alize
d A
ng
le
Phase ErrErr Bound
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5
-20
0
20
Normalized Frequency
Log
Mag
(dB)
Magnitude Responses of Original Filter and Synthesized Filter
OriSyn
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5
-60
-40
-20
Normalized Frequency
Log
Mag
(dB)
Magnitude Error between Original Filter and Synthesized Filter
Mag ErrMinimax BoundSub-Opt Bound
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5
-0.01
0
0.01
Phase Error between Original Filter and Synthesized Filter
Normalized FrequencyNo
rmali
zed
Angl
e
Phase ErrorMinimax BoundSub-Opt Bound
19
NMDFB Filtering Simulation 2
M = 256, D = 64 TriangularNon Linear Phase Filtering
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5
-20
0
20
Normalized Frequency
Log
Mag
(dB
)
Magnitude Responses of Original Filter and Synthesized Filter
OriSyn
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5-70
-60
-50
-40
Normalized Frequency
Log
Mag
(dB
)
Magnitude Error between Original Filter and Synthesized Filter
Mag ErrMinimax BoundSub-Opt Bound
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5
-1
0
1
x 10-3 Phase Error between Original Filter and Synthesized Filter
Normalized Frequency
Nor
mal
ized
Ang
le
Phase ErrorMinimax BoundSub-Opt Bound
20
NMDFB Filtering: Fractional Delay
M = 64, D = 16 TriangularFractional Delay Filtering
-0.5 0 0.5-5
0
5x 10
-3
Normalized Frequency
dB
Mag Res, Dly = 0 SMP
-0.5 0 0.5-5
0
5x 10
-3
Normalized Frequency
dB
Mag Res, Dly = 0.5 SMP
-0.5 0 0.5-5
0
5x 10
-3
Normalized Frequency
dB
Mag Res, Dly = -0.5 SMP
-10 -5 0 5 10
0
0.5
1Impz Dly = 0
SMPs / n
Am
p
ReIm
-10 -5 0 5 10
0
0.5
1Impz Dly = 0.5
SMPs / n
Am
p
ReIm
-10 -5 0 5 10
0
0.5
1Impz Dly = -0.5
SMPs / n
Am
p
ReIm
21
NMDFB Filtering Workload
=
: Analysis Filter Bank Length: Synthesis Filter Bank LengthM : Number of PathsN: Number of Intermediate Processing Elements
22
NMDFB APPLICATIONS
1. Wideband Signal Processing: Effectively reducing the hardware processing rate via NMDFB.
2. Filtering: Linear phase, Non-linear phase, Fractional delay, Masking, Cascade Filtering.
3. Support block timing varying filtering. 4. Support wideband power allocation.
23
Communication Example
Time Domain Timing Recovery & Matched Filtering
NMDFB Domain Timing Recovery & Matched Filtering
256 Real Multiplies per Output
240 Real Multiplies per Output
24
Communication Example
NMDFB Timing Recovery Simulation (Submitted to ICASSP 2013)20 dB SNR / AWGN channel / 0.25 Ts Timing Error
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5-60
-40
-20
0
Normalized Freq
Mag /
dB
Spectrums: Time Domain MF, NMDFB MF
TD MF
NMDFB MF
-0.5 0 0.5-120
-100
-80
-60
-40
-20
X: 0.3125Y: -32.22
Normalized Freq
Mag /
dB
Mag Error
simulated err
err bound
-0.5 0 0.5-0.02
-0.01
0
0.01
0.02Phase Error
Normalized Freq
Radiu
s
simulated err
err bound
-2 -1 0 1 2-2
-1
0
1
2
Received Constellation = 0.25Ts
-2 -1 0 1 2-2
-1
0
1
2Timing Recovered Constellation
0 0.5 1 1.5 2
x 104
0
0.1
0.2
0.3
0.4PHASE ACCUMULATOR TIME PROFILE
Sample Index (n)
Tim
ing O
ffset
Phase Acc
Defined Timing Offset
0 0.5 1 1.5 2
x 104
-2
0
2
4
6x 10
-3 Timing Error
Sample Index (n)A
mplit
ude
10x Loop Filter Input
Loop Filter Output