VSB receiver and method for processing receiving signal in the same

• US 20020071501A1
• Filed: 12/07/2001
• Published: 06/13/2002
• Est. Priority Date: 12/08/2000
• Status: Abandoned Application

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Gu, Young Mo, Hong, Sung Ryong
• Application Number:
  US10/005,081
• Publication Number:
  US 20020071501A1
• Time in Patent Office: Days
• US Class Current: 375/321
• CPC Class Codes: H03D 1/2245 using two quadrature channels H03D1/2209 takes precedence
• CPC Class Codes: H03D 1/24 for demodulation of signals wherein one sideband or the carrier has been wholly or partially suppressed receiver circuits H04B1/302

Abstract

A VSB receiver and a method for processing a receiving signal in the same are disclosed, which is not subject to frequency offset. The VSB receiver includes an intermediate frequency signal generator generating an intermediate frequency band signal from a received signal; a demodulator generating a complex base band signal consisting of an I channel signal and a Q channel signal using the intermediate frequency band signal and at least one local carrier wave signal; and a complex base band matched filter filtering at least one of the I channel signal and the Q channel signal. In the VSB receiver, since a complex signal responds to a required channel of the I channel and the Q channel, it is possible to prevent performance of the system from being deteriorated by frequency offset.

Claims

1. A VSB receiver comprising:

an intermediate frequency signal generator generating an intermediate frequency band signal from a received signal;

a demodulator generating a complex base band signal consisting of an I channel signal and a Q channel signal using the intermediate frequency band signal and at least one local carrier wave signal; and

a complex base band matched filter filtering at least one of the I channel signal and the Q channel signal.

2. The VSB receiver of claim 1, wherein the complex base band matched filter includes a first base band matched filter filtering a real domain of the I channel signal, a second base band matched filter filtering an imaginary domain of the I channel signal, a third base band matched filter filtering a real domain of the Q channel signal, a fourth base band matched filter filtering an imaginary domain of the Q channel signal, a first adder adding the filtered real domain signals of the I channel and the Q channel output from the first base band matched filter and the second base band matched filter to output the resultant value as a new I channel signal, and a second adder adding the filtered imaginary domain signals of the I channel and the Q channel output from the second base band matched filter and the fourth base band matched filter to output the resultant value as a new Q channel signal.

3. The VSB receiver of claim 1, wherein the complex base band matched filter is designed so that a frequency characteristic H(w) is identical to a frequency spectrum R(w) of the base band signal.

4. The VSB receiver of claim 1, wherein the complex base band matched filter includes a fifth base band matched filter filtering the I channel signal, a sixth base band matched filter filtering the Q channel signal, and a third adder adding the filtered I channel signal to the real domain and the filtered Q channel signal to the imaginary domain to output the added complex signal as a new I channel signal.

5. A VSB receiver comprising:

a first multiplier multiplying a receiving signal by an intermediate frequency signal to generate an intermediate frequency band signal;

a second multiplier multiplying the intermediate frequency band signal by a first local carrier wave signal to demodulate the intermediate frequency band signal to an I channel signal;

a third multiplier multiplying the intermediate frequency band signal by a second local carrier wave signal to demodulate the intermediate frequency band signal to a Q channel signal; and

a complex base band matched filter filtering at least one of the demodulated I channel signal and the demodulated Q channel to output a complex signal.

6. The VSB receiver of claim 5, wherein the complex base band matched filter is designed so that a frequency characteristic H(w) is identical to a frequency spectrum R(w) of the base band signal.

7. The VSB receiver of claim 5, wherein the complex base matched filter includes a first base band matched filter filtering a real domain of the I channel signal, a second base band matched filter filtering an imaginary domain of the I channel signal, a third base band matched filter filtering a real domain of the Q channel signal, a fourth base band matched filter filtering an imaginary domain of the Q channel signal, a first adder adding the filtered real domain signals of the I channel and the Q channel output from the first base band matched filter and the second base band matched filter to output the resultant value as a new I channel signal, and a second adder adding the filtered imaginary domain signals of the I channel and the Q channel output from the second base band matched filter and the fourth base band matched filter to output the resultant value as a new Q channel signal.

8. The VSB receiver of claim 5, wherein the complex base band matched filter includes a fifth base band matched filter filtering the I channel signal, a sixth base band matched filter filtering the Q channel signal, and a third adder adding the filtered I channel signal to the real domain and the filtered Q channel signal to the imaginary domain to output the added complex signal as a new I channel signal.

9. The VSB receiver of claim 5, wherein the intermediate frequency signal is 2cos(wc−

wi)t.

10. The VSB receiver of claim 5, wherein the first local carrier wave is 2coswit, and the second local carrier wave is 2sinwit.

11. A method for processing a signal in a VSB receiver having a tuner, the method comprising the steps of:

generating an intermediate frequency band signal by multiplying a received signal through the tuner by an intermediate frequency signal;

generating a complex base band signal consisting of an I channel signal and a Q channel signal by multiplying the intermediate frequency band signal by an I channel local carrier wave signal and a Q channel local carrier wave signal; and

complex matched filtering at least one of the I channel signal and the Q channel signal.

12. The method of claim 11, wherein the intermediate frequency signal is 2cos(wc−

wi)t.

13. The method of claim 11, wherein the first local carrier wave is 2coswit, and the second local carrier wave is 2sinwit.