ROBUST SYMBOL TIMING RECOVERY CIRCUIT FOR TELEPHONE LINE MODEM

摘要

PURPOSE: A robust symbol timing recovery circuit for a telephone line modem is provided, which is insensitive to the instability of the clock between the transmitting end and the receiving end and interpolates the received signal without eliminating and repeating signal. CONSTITUTION: A robust symbol timing recovery circuit(1000) for a telephone line modem includes a timing estimator(300) and an interpolator(500). The interpolator(500) includes a plurality of shift registers, a control block and an interpolation block. The plurality of shift registers is connected to each other in serial to output the input samples with delaying by a period of the input sample in parallel. The control block selects 4 number of input samples place at a predetermined position among the plurality of input samples in response to the integer timing offset. And, the interpolation block outputs the output samples by interpolating the input samples selected from the control block in response to the prime number timing offset.