# US 2014/0157331 A1 · Channel scanning method for digital video broadcasting satellite signal

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- Number: US 2014/0157331 A1
- Document ID: US20140157331A1
- Status: Published application
- Kind: A1
- Application number: 14/094,891
- Filed: 2013-12-03
- Published: 2014-06-05
- Earliest claimed: 2012-12-03
- Assignees: MStar Semiconductor, Inc.
- Applicants: MStar Semiconductor, Inc.
- Inventors: Chu-Hsin Chang; Kai-Wen Cheng; Yi-Ying Liao; Tung-Sheng Lin; Tai-Lai Tung
- Web page: https://patentgrep.com/patent/US20140157331A1

## CPC

- H04N 21/6193: {involving transmission via a satellite (arrangements for data linking, networking or transporting, or for controlling an end to end session in a satellite broadcast system H04B7/18526)}
- H04H 40/90: specially adapted for satellite broadcast receiving
- H04N 21/4382: {Demodulation or channel decoding, e.g. QPSK demodulation (analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002)}
- H04N 21/4383: {Accessing a communication channel}
- H04H 20/26: Arrangements for switching distribution systems
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04H: BROADCAST COMMUNICATION (multiplex communication H04J; pictorial communication aspects of broadcast systems H04N)

## Abstract

A channel scanning method for Digital Video Broadcasting—Satellite (DVB-S) signals is provided. The method includes: scanning a radio frequency (RF) signal according to a normal frequency step; when the Nth channel is detected, obtaining a difference between a low boundary of an Nth channel and a high boundary of an (N−1)th channel; and, when the difference is within a predetermined bandwidth range, scanning the RF signal between the high boundary of the (N−1)th channel and the low boundary of the Nth channel according to a narrow frequency step. The normal frequency step is greater than the narrow frequency step.

## Claims

### Claim 1

A channel scanning method for a Digital Video Broadcasting—Satellite (DVB-S) signal, comprising:
scanning a radio frequency (RF) signal according to a normal frequency step;
when an Nth channel is detected, obtaining a difference between a low boundary of the Nth channel and a high boundary of an (N−1)th channel; and
when the difference is within a predetermined bandwidth range, scanning the RF signal between the high boundary of the (N−1)th channel and the low boundary of the Nth channel according to a narrow frequency step;
wherein, the normal frequency step is greater than the narrow frequency step.

### Claim 2 (depends on 1)

The channel scanning method according to claim 1, wherein the step of scanning the RF signal according to the normal frequency step detects the RF signal within a first adjustment interval corresponding to a tuner center frequency.

### Claim 3 (depends on 2)

The channel scanning method according to claim 2, wherein the step of scanning the RF signal according to the normal frequency step further comprises:
when no channel signal is detected from the RF signal, relocating the tuner center frequency and the corresponding first adjustment interval by the normal frequency step, and again detecting the RF signal.

### Claim 4 (depends on 2)

The channel scanning method according to claim 2, further comprising:
when the difference falls out of the predetermined bandwidth range, recording the high boundary of the Nth channel, locking the Nth channel, relocating the tuner center frequency and the corresponding first adjustment interval by the normal frequency step, and iterating the step of scanning the RF signal according to the normal frequency step.

### Claim 5 (depends on 4)

The channel scanning method according to claim 4, wherein locking the Nth channel is locking a center frequency and a symbol rate of the Nth channel.

### Claim 6 (depends on 1)

The channel scanning method according to claim 1, wherein the step of scanning the RF signal according to the narrow frequency step detects the RF signal according to a tuner center frequency and a corresponding second adjustment interval.

### Claim 7 (depends on 6)

The channel scanning method according to claim 6, wherein the step of scanning the RF signal according to the narrow frequency step further comprises:
when no channel signal is detected from the RF signal, relocating the tuner center frequency and the corresponding second adjustment interval by the narrow frequency step, and again detecting the RF signal.

### Claim 8 (depends on 6)

The channel scanning method according to claim 6, wherein the step of scanning the RF signal according to the narrow frequency step further comprises:
when an Mth channel is detected from the RF signal, recording a high boundary of the Mth channel;
when the high boundary of the Mth channel is greater than or equal to the low boundary of the Nth channel, iterating the step of scanning the RF signal according to the normal frequency step; and
when the high boundary of the Mth channel is smaller than the low boundary of the Nth channel, relocating the tuner center frequency and the corresponding second adjustment interval by the narrow frequency step, and again detecting the RF signal.

### Claim 9 (depends on 8)

The channel scanning method according to claim 8, wherein locking the Mth channel is locking a center frequency and a symbol rate of the Mth channel.