Non-coherent synchronous direct conversion receive transmit system for estimating frequency offset

A non-coherent synchronous direct conversion receiving device having a frequency offset compensation function is provided to digitally measure a frequency offset by using data information only without reference frequency information, and to calculate an error value of the frequency offset to control a reference frequency two times through an interface signal, so that AFC(Automatic Frequency offset Correction) can be stably operated. An RF(Radio Frequency) receiving module(200) filters and low noise-amplifies a signal received through an antenna, demodulates the signal into baseband I(In-phase)/Q(Quadrature) signals through a direction conversion method according to a reference clock, and filters the signals in low band. I/Q analog/digital converters(207,208) convert the I/Q signals into digital signals. A digital signal processing module(210) detects the digital signals, controls bandwidths of a variable receiving filter(212) according to the detected results, extracts frequency offset information from the digital signals to compensate a frequency offset according to a symbol transmission rate, and compensates a frequency error by using the detected results, then applies a voltage equivalent to a sum of each compensation value to the RF receiving module(200) to compensate the frequency offset.