Patent ID: 6526107
Filing Date: 2003-02-25
Classification: H04J,H04L

Abstract:
A synchronization acquiring circuit, comprising:synchronization detecting means for detecting a reception frame synchronization pattern from a demodulated baseband signal; C/N determining means for determining a C/N value of a transmission path from the demodulated baseband signal; correlation detection reference value calculating means for outputting as a correlation detection reference value; the number of bits in a reception frame synchronization pattern that coincides with the bits of the frame synchronization pattern on a transmitting side that allows synchronization to be detected and maintained based on the determined C/N value; coincided bit number calculating means for comparing the bits of the reception frame synchronization pattern detected by the synchronization detecting means with the bits of frame synchronization pattern on the transmitting side and for calculating the number of coincided bits; comparing means for outputting said frame synchronization pattern detection signal when the number of bits calculated by the coincided bit number calculating means is equal to or larger than a correlation detection reference value; first detecting means for detecting that the frame synchronization pattern detecting signal is output by the comparing means for every 1-frame period; and second detecting means for detecting that a signal, which is received by using a part of a predetermined modulated wave of modulated waves used in a transmission signal, has a quality equal to or higher than a predetermined quality depending on whether the probability that a distribution value of the signal point positioning of the signal received will be within a predetermined range is equal to or higher than a predetermined probability, wherein synchronization is regarded as established when the first detecting means detects a frame synchronization and the second detecting means detects that the reception signal has the quality equal to or higher than the predetermined quality.