Digital sampling rate converter for compensating for drop of in-band signal

• US 20050280564A1
• Filed: 09/27/2004
• Published: 12/22/2005
• Est. Priority Date: 06/22/2004
• Status: Active Grant

• Current Assignee: Hanwha Systems Co., Ltd.
• Original Assignee: Samsung Thales Company Limited (Hanwha Corporation)
• Inventors: Lee, Kyu-Ha
• Granted Patent: US 7,035,888 B2
• Time in Patent Office: Days
• US Class Current: 341/61
• CPC Class Codes: H03H 17/0671 Cascaded integrator-comb [CIC] filters

Abstract

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.

Claims

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 bands

wherein the compensation unit compensates for an attenuation of a frequency response characteristic having a sinc function form and an approximate linear phase characteristic.

3. The digital sampling rate converter of claim 1, wherein compensation filter coefficients c₀ and c₁ 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

$\mathrm{If}$

 

⁢

E M ⁡

( c ) >

ɛ

, minimize c ⁢

E M ⁡

( C ) , and $\mathrm{if}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{not},\begin{array}{c}\mathrm{minimize}\\ c\end{array}<br><br>E_G<br><br>\left(C\right),<br><br>\mathrm{where},<br><br>\begin{array}{c}{E}_M<br><br>\left(c\right)=\max <br><br><br><br>e_M<br><br>\left(c\right)<br><br>-\min <br><br><br><br>e_M<br><br>\left(c\right)<br><br>,\\ E_G<br><br>\left(c\right)=\max <br><br><br><br>e_G<br><br>\left(c\right)<br><br>-\min <br><br><br><br>e_G<br><br>\left(c\right)<br><br>,\\ E_M<br><br>\left(c,{\mathrm{\omega <br><br>}}_i\right)=<br><br>H<br><br>\left({\mathrm{\omega <br><br>}}_i\right)<br><br>H_{\mathrm{ALC}}<br><br>\left(c,{\mathrm{\omega <br><br>}}_i\right)<br><br>,\\ e_G<br><br>\left(c,{\mathrm{\omega <br><br>}}_i\right)=-\frac{d<br><br><<br><br>\left\{H<br><br>\left({\mathrm{\omega <br><br>}}_i\right)<br><br>H_{\mathrm{ALC}}<br><br>\left(e,{\mathrm{\omega <br><br>}}_i\right)\right\}}{d<br><br>\mathrm{\omega <br><br>}},\mathrm{and}\\ c=\left[c_0,c_1\right].\end{array}$

2. (canceled)

4. 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.