VSB receiver

A VSB receiver for receiving a terrestrial digital broadcasting signal obtained by subjecting video and audio data constructed in a format having a segment synchronizing signal at the head of each of segments and a field synchronizing signal at the head of each of fields to multi-valued VSB (octal or hexadecimal VSB) modulation and transmitted, characterized by comprising:

• segment synchronization detection means for detecting said segment synchronizing signal from the received signal which has been subjected to said multi-valued VSB modulation;
• and
• automatic gain control means whose loop gain is feedback-controlled through a gain detector, an amplifier, and a loop filter on the basis of said segment synchronizing signal detected by said segment synchronization detection means such that the level of said segment synchronizing signal is constant,
• said automatic gain control means switching the gain of said amplifier to a large value until said segment synchronizing signal is detected, while switching the gain of said amplifier to a small value after it is detected in accordance with the segment synchronization detecting signal indicating the presence or absence of the detection of said segment synchronizing signal.

A VSB receiver for receiving a terrestrial digital broadcasting signal obtained by subjecting video and audio data constructed in a format having a segment synchronizing signal at the head of each of segments and a field synchronizing signal at the head of each of fields to multi-valued VSB (octal or hexadecimal VSB) modulation and transmitted, characterized by comprising:

• segment synchronization detection means for detecting said segment synchronizing signal from the received signal which has been subjected to said multi-valued VSB modulation;
• automatic gain control means whose loop gain is feedback-controlled through a gain detector, an amplifier, and a loop filter on the basis of said segment synchronizing signal detected by said segment synchronization detection means such that the level of said segment synchronizing signal is constant;
• and
• clock regeneration means whose loop gain is feedback-controlled through a clock frequency detector, an amplifier, a loop filter, and a variable clock oscillator such that a clock frequency to be regenerated coincides with the clock frequency of the received signal on the basis of said segment synchronizing signal detected by said segment synchronization detection means,
• each of said automatic gain control means and said clock regeneration means switching said loop filter to a wide band until said segment synchronizing signal is detected, while switching said loop filter to a narrow band after it is detected in accordance with the segment synchronization detecting signal indicating the presence or absence of the detection of said segment synchronizing signal.

A VSB receiver for receiving a terrestrial digital broadcasting signal obtained by subjecting video and audio data constructed in a format having a segment synchronizing signal at the head of each of segments and a field synchronizing signal at the head of each of fields to multi-valued VSB (octal or hexadecimal VSB) modulation and transmitted, characterized by comprising:

• segment synchronization detection means for detecting said segment synchronizing signal from the received signal which has been subjected to said multi-valued VSB modulation;
• automatic gain control means whose loop gain is feedback-controlled through a gain detector, an amplifier, and a loop filter on the basis of said segment synchronizing signal detected by said segment synchronization detection means such that the level of said segment synchronizing signal is constant;
• and
• clock regeneration means whose loop gain is feedback-controlled through a clock frequency detector, an amplifier, a loop filter, and a variable clock oscillator such that a clock frequency to be regenerated coincides with the clock frequency of the received signal on the basis of said segment synchronizing signal detected by said segment synchronization detection means,
• each of said automatic gain control means and said clock regeneration means switching the gain of said amplifier to a large value until said segment synchronizing signal is detected, while switching the gain of said amplifier to a small value after it is detected in accordance with the segment synchronization detecting signal indicating the presence or absence of the detection of said segment synchronizing signal.

A VSB receiver for receiving a terrestrial digital broadcasting signal obtained by subjecting video and audio data constructed in a format having a segment synchronizing signal at the head of each of segments and a field synchronizing signal at the head of each of fields to multi-valued VSB (octal or hexadecimal VSB) modulation and transmitted, characterized by comprising:

• segment synchronization detection means for detecting said segment synchronizing signal from the received signal which has been subjected to said multi-valued VSB modulation;
• automatic gain control means whose loop gain is feedback-controlled through a gain detector, an amplifier, and a loop filter on the basis of said segment synchronizing signal detected by said segment synchronization detection means such that the level of said segment synchronizing signal is constant;
• and
• clock regeneration means whose loop gain is feedback-controlled through a clock frequency detector, an amplifier, a loop filter, and a variable clock oscillator such that a clock frequency to be regenerated coincides with the clock frequency of the received signal on the basis of said segment synchronizing signal detected by said segment synchronization detection means,
• said automatic gain control means switching said loop filter to a wide band until said segment synchronizing signal is detected, while switching said loop filter to a narrow band after it is detected in accordance with the segment synchronization detecting signal indicating the presence or absence of the detection of said segment synchronizing signal, and said clock regeneration means switching the gain of said amplifier to a large value until said segment synchronizing signal is detected, while switching the gain of said amplifier to a small value after it is detected in accordance with said segment synchronization detecting signal.

A VSB receiver for receiving a terrestrial digital broadcasting signal obtained by subjecting video and audio data constructed in a format having a segment synchronizing signal at the head of each of segments and a field synchronizing signal at the head of each of fields to multi-valued VSB (octal or hexadecimal VSB) modulation and transmitted, characterized by comprising:

• segment synchronization detection means for detecting said segment synchronizing signal from the received signal which has been subjected to said multi-valued VSB modulation;
• automatic gain control means whose loop gain is feedback-controlled through a gain detector, an amplifier, and a loop filter on the basis of said segment synchronizing signal detected by said segment synchronization detection means such that the level of said segment synchronizing signal is constant;
• and
• clock regeneration means whose loop gain is feedback-controlled through a clock frequency detector, an amplifier, a loop filter, and a variable clock oscillator such that a clock frequency to be regenerated coincides with the clock frequency of the received signal on the basis of said segment synchronizing signal detected by said segment synchronization detection means,
• said automatic gain control means switching the gain of said amplifier to a large value until said segment synchronizing signal is detected, while switching the gain of said amplifier to a small value after it is detected in accordance with the segment synchronization detecting signal indicating the presence or absence of the detection of said segment synchronizing signal, and said clock regeneration means switching said loop filter to a wide band until said segment synchronizing signal is detected, while switching said loop filter to a narrow band after it is detected in accordance with said segment synchronization detecting signal.

A VSB receiver for receiving a terrestrial digital broadcasting signal obtained by subjecting video and audio data constructed in a format having a segment synchronizing signal at the head of each of segments and a field synchronizing signal at the head of each of fields to multi-valued VSB (octal or hexadecimal VSB) modulation and transmitted, characterized by comprising:

• field synchronization detection means for detecting said field synchronizing signal from the received signal which has been subjected to said multi-valued VSB modulation;
• and
• automatic gain control means whose loop gain is feedback-controlled through a gain detector, an amplifier, and a loop filter on the basis of said field synchronizing signal detected by said field synchronization detection means such that the level of said field synchronizing signal is constant,
• said automatic gain control means switching said loop filter to a wide band until said field synchronizing signal is detected, while switching said loop filter to a narrow band after it is detected in accordance with the field synchronization detecting signal indicating the presence or absence of the detection of said field synchronizing signal.

A VSB receiver for receiving a terrestrial digital broadcasting signal obtained by subjecting video and audio data constructed in a format having a segment synchronizing signal at the head of each of segments and a field synchronizing signal at the head of each of fields to multi-valued VSB (octal or hexadecimal VSB) modulation and transmitted, characterized by comprising:

• field synchronization detection means for detecting said field synchronizing signal from the received signal which has been subjected to said multi-valued VSB modulation;
• and
• automatic gain control means whose loop gain is feedback-controlled through a gain detector, an amplifier, and a loop filter on the basis of said field synchronizing signal detected by said field synchronization detection means such that the level of said field synchronizing signal is constant,
• said automatic gain control means switching the gain of said amplifier to a large value until said field synchronizing signal is detected, while switching the gain of said amplifier to a small value after it is detected in accordance with the field synchronization detecting signal indicating the presence or absence of the detection of said field synchronizing signal.

A VSB receiver for receiving a terrestrial digital broadcasting signal obtained by subjecting video and audio data constructed in a format having a segment synchronizing signal at the head of each of segments and a field synchronizing signal at the head of each of fields to multi-valued VSB (octal or hexadecimal VSB) modulation and transmitted, characterized by comprising:

• field synchronization detection means for detecting said field synchronizing signal from the received signal which has been subjected to said multi-valued VSB modulation;
• automatic gain control means whose loop gain is feedback-controlled through a gain detector, an amplifier, and a loop filter on the basis of said field synchronizing signal detected by said field synchronization detection means such that the level of said field synchronizing signal is constant;
• and
• clock regeneration means whose loop gain is feedback-controlled through a clock frequency detector, an amplifier, a loop filter, and a variable clock oscillator such that a clock frequency to be regenerated coincides with the clock frequency of the received signal on the basis of said field synchronizing signal detected by said field synchronization detection means,
• each of said automatic gain control means and said clock regeneration means switching said loop filter to a wide band until said field synchronizing signal is detected, while switching said loop filter to a narrow band after it is detected in accordance with the field synchronization detecting signal indicating the presence or absence of the detection of said field synchronizing signal.

A VSB receiver for receiving a terrestrial digital broadcasting signal obtained by subjecting video and audio data constructed in a format having a segment synchronizing signal at the head of each of segments and a field synchronizing signal at the head of each of fields to multi-valued VSB (octal or hexadecimal VSB) modulation and transmitted, characterized by comprising:

• field synchronization detection means for detecting said field synchronizing signal from the received signal which has been subjected to said multi-valued VSB modulation;
• automatic gain control means whose loop gain is feedback-controlled through a gain detector, an amplifier, and a loop filter on the basis of said field synchronizing signal detected by said field synchronization detection means such that the level of said field synchronizing signal is constant;
• and
• clock regeneration means whose loop gain is feedback-controlled through a clock frequency detector, an amplifier, a loop filter, and a variable clock oscillator such that a clock frequency to be regenerated coincides with the clock frequency of the received signal on the basis of said field synchronizing signal detected by said field synchronization detection means,
• each of said automatic gain control means and said clock regeneration means switching the gain of said amplifier to a large value until said field synchronizing signal is detected, while switching the gain of said amplifier to a small value after it is detected in accordance with the field synchronization detecting signal indicating the presence or absence of the detection of said field synchronizing signal.

A VSB receiver for receiving a terrestrial digital broadcasting signal obtained by subjecting video and audio data constructed in a format having a segment synchronizing signal at the head of each of segments and a field synchronizing signal at the head of each of fields to multi-valued VSB (octal or hexadecimal VSB) modulation and transmitted, characterized by comprising:

• field synchronization detection means for detecting said field synchronizing signal from the received signal which has been subjected to said multi-valued VSB modulation;
• automatic gain control means whose loop gain is feedback-controlled through a gain detector, an amplifier, and a loop filter on the basis of said field synchronizing signal detected by said field synchronization detection means such that the level of said field synchronizing signal is constant;
• and
• clock regeneration means whose loop gain is feedback-controlled through a clock frequency detector, an amplifier, a loop filter, and a variable clock oscillator such that a clock frequency to be regenerated coincides with the clock frequency of the received signal on the basis of said field synchronizing signal detected by said field synchronization detection means,
• said automatic gain control means switching said loop filter to a wide band until said field synchronizing signal is detected, while switching said loop filter to a narrow band after it is detected in accordance with the field synchronization detecting signal indicating the presence or absence of the detection of said field synchronizing signal, and said clock regeneration means switching the gain of said amplifier to a large value until said field synchronizing signal is detected, while switching the gain of said amplifier to a small value after it is detected in accordance with said field synchronization detecting signal.

A VSB receiver for receiving a terrestrial digital broadcasting signal obtained by subjecting video and audio data constructed in a format having a segment synchronizing signal at the head of each of segments and a field synchronizing signal at the head of each of fields to multi-valued VSB (octal or hexadecimal VSB) modulation and transmitted, characterized by comprising:

• field synchronization detection means for detecting said field synchronizing signal from the received signal which has been subjected to said multi-valued VSB modulation;
• automatic gain control means whose loop gain is feedback-controlled through a gain detector, an amplifier, and a loop filter on the basis of said field synchronizing signal detected by said field synchronization detection means such that the level of said field synchronizing signal is constant;
• and
• clock regeneration means whose loop gain is feedback-controlled through a clock frequency detector, an amplifier, a loop filter, and a variable clock oscillator such that a clock frequency to be regenerated coincides with the clock frequency of the received signal on the basis of said field synchronizing signal detected by said field synchronization detection means,
• said automatic gain control means switching the gain of said amplifier to a large value until said field synchronizing signal is detected, while switching the gain of said amplifier to a small value after it is detected in accordance with the field synchronization detecting signal indicating the presence or absence of the detection of said field synchronizing signal, and said clock regeneration means switching said loop filter to a wide band until said field synchronizing signal is detected, while switching said loop filter to a narrow band after it is detected in accordance with said field synchronization detecting signal.