# US 6,298,100 B1 · Phase error estimation method for a demodulator in an HDTV receiver

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- Number: US 6,298,100 B1
- Document ID: US6298100B1
- Status: Granted
- Kind: B1
- Application number: 09/427,315
- Filed: 1999-10-26
- Granted: 2001-10-02
- Earliest claimed: 1999-10-26
- Assignees: Thomson Licensing
- Inventors: Aaron Reel Bouillet
- Web page: https://patentgrep.com/patent/US6298100B1

## CPC

- H04L 27/066: {Carrier recovery circuits (H04L27/2271 takes precedence)}
- H04L 2027/003: {at baseband only}
- H04L 2027/0036: {using a recovered symbol clock}
- H04L 2027/0046: {Open loops}
- H04L 2027/0067: {Phase error detectors}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A receiver for processing a VSB modulated signal containing terrestrial broadcast high definition television information and a pilot component includes a carrier recovery network (22; FIG. 3) that produces a demodulated baseband signal. The carrier recovery network additionally responds to a locally generated control signal (Ph. Offset; 360) representing an unwanted phase offset of the pilot signal due to multipath distortion, for example. The control signal is used to compensate for the pilot phase offset before the demodulated signal is equalized. The control signal is produced by correlating received sync values with both a reference sync value (362) and a Hilbert transform of the reference sync value (363). The output of the carrier recovery network signal is phase compensated twice.

## Claims

### Claim 1

In a receiver for processing a received Vestigial Sideband (VSB) modulated signal containing a digital pilot carrier component and digital video data represented by a VSB symbol constellation, said data having a data frame format constituted by a succession of data frames comprising a field a sync component prefacing a plurality of data segments each having an associated segment sync, a method comprising the steps of:
generating a control signal representing a phase offset error of said pilot component; and
demodulating said received signal in response to the phase of said pilot component and to said control signal concurrently; wherein said generating step includes the step of:
generating the control signal as a function of a correlation between a value of a predetermined component of the received signal, and a reference value.

### Claim 2 (depends on 1)

A method according to claim 1, wherein
said predetermined component is a segment sync component of the received signal.

### Claim 3

In a receiver for processing a received Vestigial Sideband (VSB) modulated datastream containing a pilot carrier component and video data represented by a VSB symbol constellation, said data having a data frame format constituted by a succession of data frames comprising a field of sync component prefacing a plurality of data segments each having an associated segment sync, a method comprising the steps of:
generating a control signal representing a phase offset error of said pilot component; and
demodulating said received signal in response to said pilot component and to said control signal: wherein said generating step includes the step of:
generating the control signal as a function of a correlation between a value of a predetermined component of the received signal, and a reference value; wherein said correlation comprises the steps of
correlating a received sync value with a reference sync value; and
correlating said received sync value with a transformed reference sync value.

### Claim 4 (depends on 3)

A method according to claim 3, wherein
said transformed reference sync value is a Hilbert transformed value.

### Claim 5 (depends on 3)

A method according to claim 3, wherein
said sync is a segment sync component of the received signal.

### Claim 6 (depends on 3)

A method according to claim 3, wherein
said sync is a segment sync component of the received signal; and said generating step comprises the steps of
correlating a received segment sync value with a reference segment sync value; and
correlating said received segment sync value with a transformed reference segment sync value.

### Claim 7 (depends on 6)

A method according to claim 6, wherein
the transformed value is a Hilbert transformed value.