Method and circuit for acquisition

A synchronization acquiring circuit for receiving a baseband signal transferred as an intermediate frequency signal obtained by down-converting a received radio wave and for acquiring a radio frequency channel, comprising:

• first pattern detection means for receiving the baseband signal transferred by the intermediate frequency signal in a predetermined frequency range and detecting a predetermined frame synchronization pattern;
• second pattern detection means for receiving baseband signal transferred by the intermediate frequency signal in a frequency range higher than the frequency range of the intermediate frequency signal transferring the baseband signal from which said first pattern detection means can detect the frame synchronization pattern, and detecting the predetermined frame synchronization pattern;
• third pattern detection means for receiving the baseband signal transferred by the intermediate frequency signal in a frequency range lower than the frequency range of the intermediate frequency signal transferring the baseband signal from which said first pattern detection means can detect the frame synchronization pattern, and detecting the predetermined frame synchronization pattern;
• and
• carrier recovery means for establishing a frame synchronization and recovering a carrier to be used for removing a frequency error of the baseband signal when one of said first to third pattern detection means detects the frame synchronization pattern.

A synchronization acquiring circuit for receiving a baseband signal transferred as an intermediate frequency signal obtained by down-converting a received radio wave and for acquiring a radio frequency channel, comprising:

• signal conversion means for identifying a phase of a received baseband signal phase-modulated in a symbol unit and converting the baseband signal into a digital signal corresponding to the identified phase;
• a plurality of pattern detection means disposed in parallel for detecting a predetermined frame synchronization pattern transferred by the baseband signal, in accordance with the digital signal generated through conversion by said signal conversion means, each of said plurality of pattern detection means being related to a frequency of the intermediate frequency signal in a different frequency range;
• and
• frequency control means for changing the frequency of the baseband signal by using an off-set frequency corresponding to a frequency error contained in the baseband signal, when one of said plurality of pattern detection means detects the frame synchronization pattern, and for establishing a frame synchronization after said signal conversion means identifies the phase of the baseband signal.

A synchronization acquiring circuit for receiving a baseband signal transferred as an intermediate frequency signal obtained by down-converting a received radio wave and for acquiring a radio frequency channel, comprising:

• first pattern detection means for detecting a predetermined frame synchronization pattern transferred by the baseband signal, in accordance with the digital signal generated through conversion by said signal conversion means, if a center frequency of a range assigned to the radio frequency channel corresponds to a frequency of the intermediate frequency signal in a predetermined frequency range;
• second pattern detection means for detecting the predetermined frame synchronization pattern transferred by the baseband signal, in accordance with the digital signal generated through conversion by said signal conversion means, if the center frequency of the range assigned to the radio frequency channel corresponds to the frequency of the intermediate frequency signal in a frequency range higher than the frequency range of the intermediate frequency signal from which said first pattern detection means can detect the frame synchronization pattern;
• third pattern detection means for detecting the predetermined frame synchronization pattern transferred by the baseband signal, in accordance with the digital signal generated through conversion by said signal conversion means, if the center frequency of the range assigned to the radio frequency channel corresponds to the frequency of the intermediate frequency signal in a frequency range higher than the frequency range of the intermediate frequency signal from which said second pattern detection means can detect the frame synchronization pattern;
• fourth pattern detection means for detecting the predetermined frame synchronization pattern transferred by the baseband signal, in accordance with the digital signal generated through conversion by said signal conversion means, if the center frequency of the range assigned to the radio frequency channel corresponds to the frequency of the intermediate frequency signal in a frequency range lower than the frequency range of the intermediate frequency signal from which said first pattern detection means can detect the frame synchronization pattern;
• fifth pattern detection means for detecting the predetermined frame synchronization pattern transferred by the baseband signal, in accordance with the digital signal generated through conversion by said signal conversion means, if the center frequency of the range assigned to the radio frequency channel corresponds to the frequency of the intermediate frequency signal in a frequency range lower than the frequency range of the intermediate frequency signal from which said first to fourth detection means can detect the frame synchronization pattern;
• and
• frequency control means for transforming the frequency of the baseband signal by using an off-set frequency corresponding to a frequency error contained in the baseband signal, when one of said first to fifth pattern detection means detects the frame synchronization pattern, for making said signal conversion means identify a phase of the baseband signal, and for making said first pattern detection means detect the frame synchronization pattern to thereafter establish a frame synchronization.

A synchronization acquiring method of receiving a baseband signal transferred as an intermediate frequency signal obtained by down-converting a received radio wave and for acquiring a radio frequency channel, comprising:

• a first pattern detection step of receiving the baseband signal transferred by the intermediate frequency signal in a predetermined frequency range and detecting a predetermined frame synchronization pattern;
• a second pattern detection step of receiving, at the same time as said first pattern detection step, the baseband signal transferred by the intermediate frequency signal in a frequency range higher than the frequency range of the intermediate frequency signal transferring the baseband signal from which said first pattern detection step can detect the frame synchronization pattern, and detecting the predetermined frame synchronization pattern;
• a third detection step of receiving, at the same time as said first and second pattern detection steps, the baseband signal transferred by the intermediate frequency signal in a frequency range lower than the frequency range of the intermediate frequency signal transferring the baseband signal from which said first pattern detection step can detect the frame synchronization pattern, and detecting the predetermined frame synchronization pattern;
• and
• a carrier recovery step of establishing a frame synchronization and recovering a carrier to be used for removing a frequency error of the baseband signal when one of said first to third pattern detection steps detects the frame synchronization pattern.