Thispaper describes the design of a wideband acquisition technique for a Quadrature Phase Shift Keying (QPSK) demodulator. The demodulator is designed at a frequency of 70 MHz to cater data rates up to 6 Mbps. The most important requirement of the design process is to have wide acquisition range of ±125 KHz under narrow Phase Lock Loop (PLL) bandwidth and low input Signal to Noise Ratio (SNR). Hence, a technique based on windowing, Fast Fourier Transform (FFT) and interpolation for input signal frequency estimation is implemented. The efficacy of the technique is verified with extensive simulations in MATLAB. © 2016 IEEE.