KR 2388

KR Electronics, Inc.
KR 2388 Root Raised Cosine Filter
www.krfilters.com
General Description
Features
• Root raised cosine response
• Closely matches the ideal response
• Sin(x)/x available
• Equalized for linear phase
• Supplied in phase matched pairs
KR Electronics designs and manufactures filters that approximate the raised cosine response. These filters are available as
both the cosine response and the root cosine response. Symbol rates to 75 MHz have been designed. They are also available with and without sin(x)/x compensation. Various roll off
factors alpha (α) are also available. Typical values for α fall
in the 0.3 to 0.5 range.
KR’s filters closely match the mathematical ideal response to
the –12 dB frequency and are most often designed for linear phase to the –3 dB response. Phase matching in
pairs is also commonly specified. KR 2388 is a root raised cosine filter without sin(x)/x compensation,
Fs=2 MHz and α=0.35. The typical response of KR 2388 root raised cosine is shown in the plots below.
Typical Performance
Figure 1 shows the ideal response, while Figures 2-6 show actual measured data from a typical filter.
Ideal Response
Actual Filter Response
(5 dB/div) 0.1 to 1.5 MHz
(5 dB/div) 0.1 to 1.5 MHz
18 Jan 2001 09:47:08
CH1
MEM
LOG
5 dB/
18 Jan 2001 09:47:33
REF 0 dB
CH1
PRm
PRm
Cor
Cor
START
. 100
000
MHz
STOP
Figure 1
© 2001, KR Electronics, Inc.
1 . 500
000
MHz
S31
LOG
START
5 dB/
. 100
000
REF -.75 dB
MHz
STOP
1 . 500
000
MHz
Figure 2
Page 1
KR Electronics, Inc.
www.krfilters.com
KR 2388 Root Raised Cosine Filter
Typical Performance (cont.)
Deviation From Ideal Response
Overall Frequency Response
(1 dB/div) .1 to 1.5 MHz
(10 dB/div) .1 to 10 MHz
18 Jan 2001 09:49:58
CH1
S31
/M
LOG
1 dB/
REF -.75 dB
1 : - . 65550
dB
18 Jan 2001 09:41:16
1 . 245
000
MHz
CH1
PRm
PRm
Cor
Cor
S31
LOG
10 dB/
REF -40 dB
SCALE
10 dB/div
1
START
. 100
000
MHz
STOP
1 . 500
000
MHz
START
. 100
000
MHz
STOP
Figure 3
PRm
Del
Cor
S31
000
Deviation From Linear Phase
Phase Match Between Pairs
(2°/div) .1 to 1.5 MHz
(2°/div) .1 to 1.5 MHz
18 Jan 2001 09:52:40
CH1
10 . 000
PHA
2
/
MHz
Figure 4
18 Jan 2001 09:54:39
REF 0
CH1
S31 /M
PHA
2
/
REF 0
1 : 1 . 0526
. 870
000
MHz
PRm
SCALE
2
/div
Cor
SCALE
2
/div
1
START
. 100
000
MHz
STOP
Figure 5
© 2001, KR Electronics, Inc.
1 . 000
000
MHz
START
. 100
000
MHz
STOP
1 . 000
000
MHz
Figure 6
Page 2
KR Electronics, Inc.
www.krfilters.com
KR 2388 Root Raised Cosine Filter
Specifications
Parameter
Specification
Filter type
Root Raised Cosine
Rolloff factor (α)
0.35
Fs
2 MHz
Source and load impedance
50 Ω
Deviation from ideal
< ± 1 dB to the –12 dB frequency
Deviation from linear phase
<± 2.5° to the –3 dB frequency
Phase match in pairs
<± 2.5° to the –1 dB frequency
Physical Dimensions
KR Electronics, Inc.
91 Avenel Street
Avenel, NJ 07001
© 2001, KR Electronics, Inc.
Web
Email
Phone
Fax
www.krfilters.com
[email protected]
(732) 636-1900
(732) 636-1982
Page 3