The spectrometer is the most important back-end in single antenna radio astronomy observations. The state-of-the-art designs for this type of instruments propose to reduce the effects of spectral leakage by using the Polyphase Filter Bank (PFB) technique and to achieve wideband and high resolution by using digital, reconfigurable, and high-performance computing hardware, such as commercial-available FPGA and GPU. We herein describe the development of a prototype PFB spectrometer using an integrated hardware and software development environment from National Instruments (Nl), along with FlexRIO FPGA technology for acquisition and CUDA-enabled GPU card for intensive processing. The results show that the proposed design, configured as a 4-tap PFB with 222 channels and 200MHz instantaneous bandwidth, is 95 times faster than a CPU implementation. It can be concluded that the hardware and software design approach used to prototype the spectrometer in this paper must be further studied within radio astronomy applications.