Patent ID: 8311080
Filing Date: 2012-11-13
Classification: H04B

Abstract:
1. A synchronization decision circuit, comprising: a synchronization decision unit that receives an information signal from a demodulation unit that de-spreads a reception spread code of a received signal for a demodulation to produce the information signal, using a local spread code which is allocated to a local terminal in accordance with a code division multiple access, the synchronization decision unit measuring a level of the information signal to calculate an SIR (Signal to Interference Ratio) data and comparing the SIR data with a first threshold and a second threshold, corresponding respectively to an in sync state and an out-of sync state between the local spread code and the reception spread code, to decide if the local spread code and the reception spread code are in the in sync state or the out-of sync state, and to output a decision signal; and a threshold change setting unit that sets the first threshold and the second threshold to a same value when a level of the received signal is lower than a predetermined third threshold.