Digital sampling rate converter for compensation for drop of in-band signal
Disclosed is a digital sampling rate converter for compensating for a drop of an in-band signal, the digital sampling rate converter including a CIC (Cascaded Integrator-Comb) decimator for performing a decimation operation at a first decimation ratio based on an overall decimation ratio, for an input signal; a sub-decimator for performing a decimation operation at a second decimation ratio for a signal output from the CIC decimator; and a compensation unit for performing at least two multiplication operations and two addition operations with respect to a signal output from the sub-decimator using a lowest operation clock frequency in an assigned band.
1. A digital sampling rate converter for compensating for a drop of an in-band signal, the digital sampling rate converter comprising:
a CIC (Cascaded Integrator-Comb) decimator for performing a decimation operation on an input signal at a first decimation ratio based on an overall decimation ratio;
a sub-decimator for performing a decimation operation at a second decimation ratio on a signal output from the CIC decimator; and
a compensation unit for performing at least two multiplication operations and two addition operations on a signal output from the sub-decimator in an assigned band,
wherein the compensation unit compensates for an attenuation of a frequency response characteristic having a sinc function form and an approximate linear phase characteristic.
2. The digital sampling rate converter of claim 1 , wherein compensation filter coefficients c 0 and c 1 of the compensation unit are determined by the following equation so as to satisfy the attenuated frequency response characteristic and the approximately linear phase characteristic
If
E
M
(
c
)
>
ɛ
,
minimize
c
E
M
(
C
)
,
and
if
not
,
minimize
c
E
G
(
C
)
,
where
,
E
M
(
c
)
=
max
e
M
(
c
)
-
min
e
M
(
c
)
,
E
G
(
c
)
=
max
e
G
(
c
)
-
min
e
G
(
c
)
,
E
M
(
c
,
ω
i
)
=
H
(
ω
i
)
H
ALC
(
c
,
ω
i
)
,
e
G
(
c
,
ω
i
)
=
-
ⅆ
<
{
H
(
ω
i
)
H
ALC
(
e
,
ω
i
)
}
ⅆ
ω
,
and
c
=
[
c
0
,
c
1
]
.
3. A digital sampling rate converter for compensating for a drop of an in-band signal, the digital sampling rate converter comprising:
a compensation unit for performing at least two multiplication operations and two addition operations on an input signal using an operation clock frequency;
an interpolator for interpolating at a first interpolation ratio based on an overall interpolation ratio on a signal output from the compensation unit; and
a CIC (Cascaded Integrator-Comb) interpolator for interpolating a signal output from the interpolator at a second decimation ratio.